MAINTAINERS: Adjust file list for PPC pseries machine
[qemu/kevin.git] / qemu-options.hx
blobe26230bac5f0f2b8483a72c4fb5f29088bb63689
1 HXCOMM Use DEFHEADING() to define headings in both help text and rST.
2 HXCOMM Text between SRST and ERST is copied to the rST version and
3 HXCOMM discarded from C version.
4 HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to
5 HXCOMM construct option structures, enums and help message for specified
6 HXCOMM architectures.
7 HXCOMM HXCOMM can be used for comments, discarded from both rST and C.
9 DEFHEADING(Standard options:)
11 DEF("help", 0, QEMU_OPTION_h,
12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL)
13 SRST
14 ``-h``
15 Display help and exit
16 ERST
18 DEF("version", 0, QEMU_OPTION_version,
19 "-version display version information and exit\n", QEMU_ARCH_ALL)
20 SRST
21 ``-version``
22 Display version information and exit
23 ERST
25 DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
26 "-machine [type=]name[,prop[=value][,...]]\n"
27 " selects emulated machine ('-machine help' for list)\n"
28 " property accel=accel1[:accel2[:...]] selects accelerator\n"
29 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n"
30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n"
31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
32 " mem-merge=on|off controls memory merge support (default: on)\n"
33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
36 " nvdimm=on|off controls NVDIMM support (default=off)\n"
37 " memory-encryption=@var{} memory encryption object to use (default=none)\n"
38 " hmat=on|off controls ACPI HMAT support (default=off)\n"
39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n"
40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n",
41 QEMU_ARCH_ALL)
42 SRST
43 ``-machine [type=]name[,prop=value[,...]]``
44 Select the emulated machine by name. Use ``-machine help`` to list
45 available machines.
47 For architectures which aim to support live migration compatibility
48 across releases, each release will introduce a new versioned machine
49 type. For example, the 2.8.0 release introduced machine types
50 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures.
52 To allow live migration of guests from QEMU version 2.8.0, to QEMU
53 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8"
54 and "pc-q35-2.8" machines too. To allow users live migrating VMs to
55 skip multiple intermediate releases when upgrading, new releases of
56 QEMU will support machine types from many previous versions.
58 Supported machine properties are:
60 ``accel=accels1[:accels2[:...]]``
61 This is used to enable an accelerator. Depending on the target
62 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available.
63 By default, tcg is used. If there is more than one accelerator
64 specified, the next one is used if the previous one fails to
65 initialize.
67 ``vmport=on|off|auto``
68 Enables emulation of VMWare IO port, for vmmouse etc. auto says
69 to select the value based on accel. For accel=xen the default is
70 off otherwise the default is on.
72 ``dump-guest-core=on|off``
73 Include guest memory in a core dump. The default is on.
75 ``mem-merge=on|off``
76 Enables or disables memory merge support. This feature, when
77 supported by the host, de-duplicates identical memory pages
78 among VMs instances (enabled by default).
80 ``aes-key-wrap=on|off``
81 Enables or disables AES key wrapping support on s390-ccw hosts.
82 This feature controls whether AES wrapping keys will be created
83 to allow execution of AES cryptographic functions. The default
84 is on.
86 ``dea-key-wrap=on|off``
87 Enables or disables DEA key wrapping support on s390-ccw hosts.
88 This feature controls whether DEA wrapping keys will be created
89 to allow execution of DEA cryptographic functions. The default
90 is on.
92 ``nvdimm=on|off``
93 Enables or disables NVDIMM support. The default is off.
95 ``memory-encryption=``
96 Memory encryption object to use. The default is none.
98 ``hmat=on|off``
99 Enables or disables ACPI Heterogeneous Memory Attribute Table
100 (HMAT) support. The default is off.
102 ``memory-backend='id'``
103 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options.
104 Allows to use a memory backend as main RAM.
106 For example:
109 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on
110 -machine memory-backend=pc.ram
111 -m 512M
113 Migration compatibility note:
115 * as backend id one shall use value of 'default-ram-id', advertised by
116 machine type (available via ``query-machines`` QMP command), if migration
117 to/from old QEMU (<5.0) is expected.
118 * for machine types 4.0 and older, user shall
119 use ``x-use-canonical-path-for-ramblock-id=off`` backend option
120 if migration to/from old QEMU (<5.0) is expected.
122 For example:
125 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off
126 -machine memory-backend=pc.ram
127 -m 512M
129 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]``
130 Define a CXL Fixed Memory Window (CFMW).
132 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM.
134 They are regions of Host Physical Addresses (HPA) on a system which
135 may be interleaved across one or more CXL host bridges. The system
136 software will assign particular devices into these windows and
137 configure the downstream Host-managed Device Memory (HDM) decoders
138 in root ports, switch ports and devices appropriately to meet the
139 interleave requirements before enabling the memory devices.
141 ``targets.X=target`` provides the mapping to CXL host bridges
142 which may be identified by the id provided in the -device entry.
143 Multiple entries are needed to specify all the targets when
144 the fixed memory window represents interleaved memory. X is the
145 target index from 0.
147 ``size=size`` sets the size of the CFMW. This must be a multiple of
148 256MiB. The region will be aligned to 256MiB but the location is
149 platform and configuration dependent.
151 ``interleave-granularity=granularity`` sets the granularity of
152 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB
153 4096KiB, 8192KiB and 16384KiB granularities supported.
155 Example:
159 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k
160 ERST
162 DEF("M", HAS_ARG, QEMU_OPTION_M,
163 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n",
164 QEMU_ARCH_ALL)
166 SRST
167 ``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}``
168 Define an SGX EPC section.
169 ERST
171 DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
172 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
173 SRST
174 ``-cpu model``
175 Select CPU model (``-cpu help`` for list and additional feature
176 selection)
177 ERST
179 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
180 "-accel [accel=]accelerator[,prop[=value][,...]]\n"
181 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n"
182 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
183 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n"
184 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n"
185 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n"
186 " split-wx=on|off (enable TCG split w^x mapping)\n"
187 " tb-size=n (TCG translation block cache size)\n"
188 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n"
189 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n"
190 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n"
191 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
192 SRST
193 ``-accel name[,prop=value[,...]]``
194 This is used to enable an accelerator. Depending on the target
195 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By
196 default, tcg is used. If there is more than one accelerator
197 specified, the next one is used if the previous one fails to
198 initialize.
200 ``igd-passthru=on|off``
201 When Xen is in use, this option controls whether Intel
202 integrated graphics devices can be passed through to the guest
203 (default=off)
205 ``kernel-irqchip=on|off|split``
206 Controls KVM in-kernel irqchip support. The default is full
207 acceleration of the interrupt controllers. On x86, split irqchip
208 reduces the kernel attack surface, at a performance cost for
209 non-MSI interrupts. Disabling the in-kernel irqchip completely
210 is not recommended except for debugging purposes.
212 ``kvm-shadow-mem=size``
213 Defines the size of the KVM shadow MMU.
215 ``one-insn-per-tb=on|off``
216 Makes the TCG accelerator put only one guest instruction into
217 each translation block. This slows down emulation a lot, but
218 can be useful in some situations, such as when trying to analyse
219 the logs produced by the ``-d`` option.
221 ``split-wx=on|off``
222 Controls the use of split w^x mapping for the TCG code generation
223 buffer. Some operating systems require this to be enabled, and in
224 such a case this will default on. On other operating systems, this
225 will default off, but one may enable this for testing or debugging.
227 ``tb-size=n``
228 Controls the size (in MiB) of the TCG translation block cache.
230 ``thread=single|multi``
231 Controls number of TCG threads. When the TCG is multi-threaded
232 there will be one thread per vCPU therefore taking advantage of
233 additional host cores. The default is to enable multi-threading
234 where both the back-end and front-ends support it and no
235 incompatible TCG features have been enabled (e.g.
236 icount/replay).
238 ``dirty-ring-size=n``
239 When the KVM accelerator is used, it controls the size of the per-vCPU
240 dirty page ring buffer (number of entries for each vCPU). It should
241 be a value that is power of two, and it should be 1024 or bigger (but
242 still less than the maximum value that the kernel supports). 4096
243 could be a good initial value if you have no idea which is the best.
244 Set this value to 0 to disable the feature. By default, this feature
245 is disabled (dirty-ring-size=0). When enabled, KVM will instead
246 record dirty pages in a bitmap.
248 ``eager-split-size=n``
249 KVM implements dirty page logging at the PAGE_SIZE granularity and
250 enabling dirty-logging on a huge-page requires breaking it into
251 PAGE_SIZE pages in the first place. KVM on ARM does this splitting
252 lazily by default. There are performance benefits in doing huge-page
253 split eagerly, especially in situations where TLBI costs associated
254 with break-before-make sequences are considerable and also if guest
255 workloads are read intensive. The size here specifies how many pages
256 to break at a time and needs to be a valid block size which is
257 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE
258 respectively. Be wary of specifying a higher size as it will have an
259 impact on the memory. By default, this feature is disabled
260 (eager-split-size=0).
262 ``notify-vmexit=run|internal-error|disable,notify-window=n``
263 Enables or disables notify VM exit support on x86 host and specify
264 the corresponding notify window to trigger the VM exit if enabled.
265 ``run`` option enables the feature. It does nothing and continue
266 if the exit happens. ``internal-error`` option enables the feature.
267 It raises a internal error. ``disable`` option doesn't enable the feature.
268 This feature can mitigate the CPU stuck issue due to event windows don't
269 open up for a specified of time (i.e. notify-window).
270 Default: notify-vmexit=run,notify-window=0.
272 ERST
274 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
275 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n"
276 " [,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n"
277 " set the number of initial CPUs to 'n' [default=1]\n"
278 " maxcpus= maximum number of total CPUs, including\n"
279 " offline CPUs for hotplug, etc\n"
280 " drawers= number of drawers on the machine board\n"
281 " books= number of books in one drawer\n"
282 " sockets= number of sockets in one book\n"
283 " dies= number of dies in one socket\n"
284 " clusters= number of clusters in one die\n"
285 " cores= number of cores in one cluster\n"
286 " threads= number of threads in one core\n"
287 "Note: Different machines may have different subsets of the CPU topology\n"
288 " parameters supported, so the actual meaning of the supported parameters\n"
289 " will vary accordingly. For example, for a machine type that supports a\n"
290 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n"
291 " sequentially mean as below:\n"
292 " sockets means the number of sockets on the machine board\n"
293 " cores means the number of cores in one socket\n"
294 " threads means the number of threads in one core\n"
295 " For a particular machine type board, an expected CPU topology hierarchy\n"
296 " can be defined through the supported sub-option. Unsupported parameters\n"
297 " can also be provided in addition to the sub-option, but their values\n"
298 " must be set as 1 in the purpose of correct parsing.\n",
299 QEMU_ARCH_ALL)
300 SRST
301 ``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]``
302 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on
303 the machine type board. On boards supporting CPU hotplug, the optional
304 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be
305 added at runtime. When both parameters are omitted, the maximum number
306 of CPUs will be calculated from the provided topology members and the
307 initial CPU count will match the maximum number. When only one of them
308 is given then the omitted one will be set to its counterpart's value.
309 Both parameters may be specified, but the maximum number of CPUs must
310 be equal to or greater than the initial CPU count. Product of the
311 CPU topology hierarchy must be equal to the maximum number of CPUs.
312 Both parameters are subject to an upper limit that is determined by
313 the specific machine type chosen.
315 To control reporting of CPU topology information, values of the topology
316 parameters can be specified. Machines may only support a subset of the
317 parameters and different machines may have different subsets supported
318 which vary depending on capacity of the corresponding CPU targets. So
319 for a particular machine type board, an expected topology hierarchy can
320 be defined through the supported sub-option. Unsupported parameters can
321 also be provided in addition to the sub-option, but their values must be
322 set as 1 in the purpose of correct parsing.
324 Either the initial CPU count, or at least one of the topology parameters
325 must be specified. The specified parameters must be greater than zero,
326 explicit configuration like "cpus=0" is not allowed. Values for any
327 omitted parameters will be computed from those which are given.
329 For example, the following sub-option defines a CPU topology hierarchy
330 (2 sockets totally on the machine, 2 cores per socket, 2 threads per
331 core) for a machine that only supports sockets/cores/threads.
332 Some members of the option can be omitted but their values will be
333 automatically computed:
337 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8
339 The following sub-option defines a CPU topology hierarchy (2 sockets
340 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads
341 per core) for PC machines which support sockets/dies/cores/threads.
342 Some members of the option can be omitted but their values will be
343 automatically computed:
347 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16
349 The following sub-option defines a CPU topology hierarchy (2 sockets
350 totally on the machine, 2 clusters per socket, 2 cores per cluster,
351 2 threads per core) for ARM virt machines which support sockets/clusters
352 /cores/threads. Some members of the option can be omitted but their values
353 will be automatically computed:
357 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16
359 Historically preference was given to the coarsest topology parameters
360 when computing missing values (ie sockets preferred over cores, which
361 were preferred over threads), however, this behaviour is considered
362 liable to change. Prior to 6.2 the preference was sockets over cores
363 over threads. Since 6.2 the preference is cores over sockets over threads.
365 For example, the following option defines a machine board with 2 sockets
366 of 1 core before 6.2 and 1 socket of 2 cores after 6.2:
370 -smp 2
372 Note: The cluster topology will only be generated in ACPI and exposed
373 to guest if it's explicitly specified in -smp.
374 ERST
376 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
377 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
378 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
379 "-numa dist,src=source,dst=destination,val=distance\n"
380 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n"
381 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n"
382 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n",
383 QEMU_ARCH_ALL)
384 SRST
385 ``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
387 ``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
389 ``-numa dist,src=source,dst=destination,val=distance``
391 ``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]``
393 ``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]``
395 ``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]``
396 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA
397 distance from a source node to a destination node. Set the ACPI
398 Heterogeneous Memory Attributes for the given nodes.
400 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and
401 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a
402 contiguous range of CPU indexes (or a single VCPU if lastcpu is
403 omitted). A non-contiguous set of VCPUs can be represented by
404 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is
405 omitted on all nodes, VCPUs are automatically split between them.
407 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a
408 NUMA node:
412 -numa node,cpus=0-2,cpus=5
414 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option
415 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to
416 assign CPU objects to a node using topology layout properties of
417 CPU. The set of properties is machine specific, and depends on used
418 machine type/'\ ``smp``\ ' options. It could be queried with
419 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ '
420 property specifies node to which CPU object will be assigned, it's
421 required for node to be declared with '\ ``node``\ ' option before
422 it's used with '\ ``cpu``\ ' option.
424 For example:
428 -M pc \
429 -smp 1,sockets=2,maxcpus=2 \
430 -numa node,nodeid=0 -numa node,nodeid=1 \
431 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
433 '\ ``memdev``\ ' option assigns RAM from a given memory backend
434 device to a node. It is recommended to use '\ ``memdev``\ ' option
435 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ '
436 option provides better performance and more control over the
437 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of
438 '\ ``-memory-backend-ram``\ ' allows memory preallocation).
440 For compatibility reasons, legacy '\ ``mem``\ ' option is
441 supported in 5.0 and older machine types. Note that '\ ``mem``\ '
442 and '\ ``memdev``\ ' are mutually exclusive. If one node uses
443 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ '
444 option, and vice versa.
446 Users must specify memory for all NUMA nodes by '\ ``memdev``\ '
447 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support
448 for '\ ``-numa node``\ ' without memory specified was removed.
450 '\ ``initiator``\ ' is an additional option that points to an
451 initiator NUMA node that has best performance (the lowest latency or
452 largest bandwidth) to this NUMA node. Note that this option can be
453 set only when the machine property 'hmat' is set to 'on'.
455 Following example creates a machine with 2 NUMA nodes, node 0 has
456 CPU. node 1 has only memory, and its initiator is node 0. Note that
457 because node 0 has CPU, by default the initiator of node 0 is itself
458 and must be itself.
462 -machine hmat=on \
463 -m 2G,slots=2,maxmem=4G \
464 -object memory-backend-ram,size=1G,id=m0 \
465 -object memory-backend-ram,size=1G,id=m1 \
466 -numa node,nodeid=0,memdev=m0 \
467 -numa node,nodeid=1,memdev=m1,initiator=0 \
468 -smp 2,sockets=2,maxcpus=2 \
469 -numa cpu,node-id=0,socket-id=0 \
470 -numa cpu,node-id=0,socket-id=1
472 source and destination are NUMA node IDs. distance is the NUMA
473 distance from source to destination. The distance from a node to
474 itself is always 10. If any pair of nodes is given a distance, then
475 all pairs must be given distances. Although, when distances are only
476 given in one direction for each pair of nodes, then the distances in
477 the opposite directions are assumed to be the same. If, however, an
478 asymmetrical pair of distances is given for even one node pair, then
479 all node pairs must be provided distance values for both directions,
480 even when they are symmetrical. When a node is unreachable from
481 another node, set the pair's distance to 255.
483 Note that the -``numa`` option doesn't allocate any of the specified
484 resources, it just assigns existing resources to NUMA nodes. This
485 means that one still has to use the ``-m``, ``-smp`` options to
486 allocate RAM and VCPUs respectively.
488 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth
489 Information between initiator and target NUMA nodes in ACPI
490 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can
491 create memory requests, usually it has one or more processors.
492 Target NUMA node contains addressable memory.
494 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is
495 the memory hierarchy of the target NUMA node: if hierarchy is
496 'memory', the structure represents the memory performance; if
497 hierarchy is 'first-level\|second-level\|third-level', this
498 structure represents aggregated performance of memory side caches
499 for each domain. type of 'data-type' is type of data represented by
500 this structure instance: if 'hierarchy' is 'memory', 'data-type' is
501 'access\|read\|write' latency or 'access\|read\|write' bandwidth of
502 the target memory; if 'hierarchy' is
503 'first-level\|second-level\|third-level', 'data-type' is
504 'access\|read\|write' hit latency or 'access\|read\|write' hit
505 bandwidth of the target memory side cache.
507 lat is latency value in nanoseconds. bw is bandwidth value, the
508 possible value and units are NUM[M\|G\|T], mean that the bandwidth
509 value are NUM byte per second (or MB/s, GB/s or TB/s depending on
510 used suffix). Note that if latency or bandwidth value is 0, means
511 the corresponding latency or bandwidth information is not provided.
513 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory
514 belongs. size is the size of memory side cache in bytes. level is
515 the cache level described in this structure, note that the cache
516 level 0 should not be used with '\ ``hmat-cache``\ ' option.
517 associativity is the cache associativity, the possible value is
518 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy
519 is the write policy. line is the cache Line size in bytes.
521 For example, the following options describe 2 NUMA nodes. Node 0 has
522 2 cpus and a ram, node 1 has only a ram. The processors in node 0
523 access memory in node 0 with access-latency 5 nanoseconds,
524 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access
525 memory in NUMA node 1 with access-latency 10 nanoseconds,
526 access-bandwidth is 100 MB/s. And for memory side cache information,
527 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB,
528 policy is write-back, the cache Line size is 8 bytes:
532 -machine hmat=on \
533 -m 2G \
534 -object memory-backend-ram,size=1G,id=m0 \
535 -object memory-backend-ram,size=1G,id=m1 \
536 -smp 2,sockets=2,maxcpus=2 \
537 -numa node,nodeid=0,memdev=m0 \
538 -numa node,nodeid=1,memdev=m1,initiator=0 \
539 -numa cpu,node-id=0,socket-id=0 \
540 -numa cpu,node-id=0,socket-id=1 \
541 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \
542 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \
543 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \
544 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \
545 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \
546 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8
547 ERST
549 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
550 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
551 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
552 SRST
553 ``-add-fd fd=fd,set=set[,opaque=opaque]``
554 Add a file descriptor to an fd set. Valid options are:
556 ``fd=fd``
557 This option defines the file descriptor of which a duplicate is
558 added to fd set. The file descriptor cannot be stdin, stdout, or
559 stderr.
561 ``set=set``
562 This option defines the ID of the fd set to add the file
563 descriptor to.
565 ``opaque=opaque``
566 This option defines a free-form string that can be used to
567 describe fd.
569 You can open an image using pre-opened file descriptors from an fd
570 set:
572 .. parsed-literal::
574 |qemu_system| \\
575 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
576 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
577 -drive file=/dev/fdset/2,index=0,media=disk
578 ERST
580 DEF("set", HAS_ARG, QEMU_OPTION_set,
581 "-set group.id.arg=value\n"
582 " set <arg> parameter for item <id> of type <group>\n"
583 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
584 SRST
585 ``-set group.id.arg=value``
586 Set parameter arg for item id of type group
587 ERST
589 DEF("global", HAS_ARG, QEMU_OPTION_global,
590 "-global driver.property=value\n"
591 "-global driver=driver,property=property,value=value\n"
592 " set a global default for a driver property\n",
593 QEMU_ARCH_ALL)
594 SRST
595 ``-global driver.prop=value``
597 ``-global driver=driver,property=property,value=value``
598 Set default value of driver's property prop to value, e.g.:
600 .. parsed-literal::
602 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img
604 In particular, you can use this to set driver properties for devices
605 which are created automatically by the machine model. To create a
606 device which is not created automatically and set properties on it,
607 use -``device``.
609 -global driver.prop=value is shorthand for -global
610 driver=driver,property=prop,value=value. The longhand syntax works
611 even when driver contains a dot.
612 ERST
614 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
615 "-boot [order=drives][,once=drives][,menu=on|off]\n"
616 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
617 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
618 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
619 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
620 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
621 QEMU_ARCH_ALL)
622 SRST
623 ``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]``
624 Specify boot order drives as a string of drive letters. Valid drive
625 letters depend on the target architecture. The x86 PC uses: a, b
626 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p
627 (Etherboot from network adapter 1-4), hard disk boot is the default.
628 To apply a particular boot order only on the first startup, specify
629 it via ``once``. Note that the ``order`` or ``once`` parameter
630 should not be used together with the ``bootindex`` property of
631 devices, since the firmware implementations normally do not support
632 both at the same time.
634 Interactive boot menus/prompts can be enabled via ``menu=on`` as far
635 as firmware/BIOS supports them. The default is non-interactive boot.
637 A splash picture could be passed to bios, enabling user to show it
638 as logo, when option splash=sp\_name is given and menu=on, If
639 firmware/BIOS supports them. Currently Seabios for X86 system
640 support it. limitation: The splash file could be a jpeg file or a
641 BMP file in 24 BPP format(true color). The resolution should be
642 supported by the SVGA mode, so the recommended is 320x240, 640x480,
643 800x640.
645 A timeout could be passed to bios, guest will pause for rb\_timeout
646 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will
647 not reboot, qemu passes '-1' to bios by default. Currently Seabios
648 for X86 system support it.
650 Do strict boot via ``strict=on`` as far as firmware/BIOS supports
651 it. This only effects when boot priority is changed by bootindex
652 options. The default is non-strict boot.
654 .. parsed-literal::
656 # try to boot from network first, then from hard disk
657 |qemu_system_x86| -boot order=nc
658 # boot from CD-ROM first, switch back to default order after reboot
659 |qemu_system_x86| -boot once=d
660 # boot with a splash picture for 5 seconds.
661 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000
663 Note: The legacy format '-boot drives' is still supported but its
664 use is discouraged as it may be removed from future versions.
665 ERST
667 DEF("m", HAS_ARG, QEMU_OPTION_m,
668 "-m [size=]megs[,slots=n,maxmem=size]\n"
669 " configure guest RAM\n"
670 " size: initial amount of guest memory\n"
671 " slots: number of hotplug slots (default: none)\n"
672 " maxmem: maximum amount of guest memory (default: none)\n"
673 " Note: Some architectures might enforce a specific granularity\n",
674 QEMU_ARCH_ALL)
675 SRST
676 ``-m [size=]megs[,slots=n,maxmem=size]``
677 Sets guest startup RAM size to megs megabytes. Default is 128 MiB.
678 Optionally, a suffix of "M" or "G" can be used to signify a value in
679 megabytes or gigabytes respectively. Optional pair slots, maxmem
680 could be used to set amount of hotpluggable memory slots and maximum
681 amount of memory. Note that maxmem must be aligned to the page size.
683 For example, the following command-line sets the guest startup RAM
684 size to 1GB, creates 3 slots to hotplug additional memory and sets
685 the maximum memory the guest can reach to 4GB:
687 .. parsed-literal::
689 |qemu_system| -m 1G,slots=3,maxmem=4G
691 If slots and maxmem are not specified, memory hotplug won't be
692 enabled and the guest startup RAM will never increase.
693 ERST
695 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
696 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
697 SRST
698 ``-mem-path path``
699 Allocate guest RAM from a temporarily created file in path.
700 ERST
702 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
703 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
704 QEMU_ARCH_ALL)
705 SRST
706 ``-mem-prealloc``
707 Preallocate memory when using -mem-path.
708 ERST
710 DEF("k", HAS_ARG, QEMU_OPTION_k,
711 "-k language use keyboard layout (for example 'fr' for French)\n",
712 QEMU_ARCH_ALL)
713 SRST
714 ``-k language``
715 Use keyboard layout language (for example ``fr`` for French). This
716 option is only needed where it is not easy to get raw PC keycodes
717 (e.g. on Macs, with some X11 servers or with a VNC or curses
718 display). You don't normally need to use it on PC/Linux or
719 PC/Windows hosts.
721 The available layouts are:
725 ar de-ch es fo fr-ca hu ja mk no pt-br sv
726 da en-gb et fr fr-ch is lt nl pl ru th
727 de en-us fi fr-be hr it lv nl-be pt sl tr
729 The default is ``en-us``.
730 ERST
733 DEF("audio", HAS_ARG, QEMU_OPTION_audio,
734 "-audio [driver=]driver[,prop[=value][,...]]\n"
735 " specifies default audio backend when `audiodev` is not\n"
736 " used to create a machine or sound device;"
737 " options are the same as for -audiodev\n"
738 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n"
739 " specifies the audio backend and device to use;\n"
740 " apart from 'model', options are the same as for -audiodev.\n"
741 " use '-audio model=help' to show possible devices.\n",
742 QEMU_ARCH_ALL)
743 SRST
744 ``-audio [driver=]driver[,model=value][,prop[=value][,...]]``
745 If the ``model`` option is specified, ``-audio`` is a shortcut
746 for configuring both the guest audio hardware and the host audio
747 backend in one go. The guest hardware model can be set with
748 ``model=modelname``. Use ``model=help`` to list the available
749 device types.
751 The following two example do exactly the same, to show how ``-audio``
752 can be used to shorten the command line length:
754 .. parsed-literal::
756 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa
757 |qemu_system| -audio pa,model=sb16
759 If the ``model`` option is not specified, ``-audio`` is used to
760 configure a default audio backend that will be used whenever the
761 ``audiodev`` property is not set on a device or machine. In
762 particular, ``-audio none`` ensures that no audio is produced even
763 for machines that have embedded sound hardware.
765 In both cases, the driver option is the same as with the corresponding
766 ``-audiodev`` option below. Use ``driver=help`` to list the available
767 drivers.
769 ERST
771 DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
772 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
773 " specifies the audio backend to use\n"
774 " Use ``-audiodev help`` to list the available drivers\n"
775 " id= identifier of the backend\n"
776 " timer-period= timer period in microseconds\n"
777 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n"
778 " in|out.fixed-settings= use fixed settings for host audio\n"
779 " in|out.frequency= frequency to use with fixed settings\n"
780 " in|out.channels= number of channels to use with fixed settings\n"
781 " in|out.format= sample format to use with fixed settings\n"
782 " valid values: s8, s16, s32, u8, u16, u32, f32\n"
783 " in|out.voices= number of voices to use\n"
784 " in|out.buffer-length= length of buffer in microseconds\n"
785 "-audiodev none,id=id,[,prop[=value][,...]]\n"
786 " dummy driver that discards all output\n"
787 #ifdef CONFIG_AUDIO_ALSA
788 "-audiodev alsa,id=id[,prop[=value][,...]]\n"
789 " in|out.dev= name of the audio device to use\n"
790 " in|out.period-length= length of period in microseconds\n"
791 " in|out.try-poll= attempt to use poll mode\n"
792 " threshold= threshold (in microseconds) when playback starts\n"
793 #endif
794 #ifdef CONFIG_AUDIO_COREAUDIO
795 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
796 " in|out.buffer-count= number of buffers\n"
797 #endif
798 #ifdef CONFIG_AUDIO_DSOUND
799 "-audiodev dsound,id=id[,prop[=value][,...]]\n"
800 " latency= add extra latency to playback in microseconds\n"
801 #endif
802 #ifdef CONFIG_AUDIO_OSS
803 "-audiodev oss,id=id[,prop[=value][,...]]\n"
804 " in|out.dev= path of the audio device to use\n"
805 " in|out.buffer-count= number of buffers\n"
806 " in|out.try-poll= attempt to use poll mode\n"
807 " try-mmap= try using memory mapped access\n"
808 " exclusive= open device in exclusive mode\n"
809 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
810 #endif
811 #ifdef CONFIG_AUDIO_PA
812 "-audiodev pa,id=id[,prop[=value][,...]]\n"
813 " server= PulseAudio server address\n"
814 " in|out.name= source/sink device name\n"
815 " in|out.latency= desired latency in microseconds\n"
816 #endif
817 #ifdef CONFIG_AUDIO_PIPEWIRE
818 "-audiodev pipewire,id=id[,prop[=value][,...]]\n"
819 " in|out.name= source/sink device name\n"
820 " in|out.stream-name= name of pipewire stream\n"
821 " in|out.latency= desired latency in microseconds\n"
822 #endif
823 #ifdef CONFIG_AUDIO_SDL
824 "-audiodev sdl,id=id[,prop[=value][,...]]\n"
825 " in|out.buffer-count= number of buffers\n"
826 #endif
827 #ifdef CONFIG_AUDIO_SNDIO
828 "-audiodev sndio,id=id[,prop[=value][,...]]\n"
829 #endif
830 #ifdef CONFIG_SPICE
831 "-audiodev spice,id=id[,prop[=value][,...]]\n"
832 #endif
833 #ifdef CONFIG_DBUS_DISPLAY
834 "-audiodev dbus,id=id[,prop[=value][,...]]\n"
835 #endif
836 "-audiodev wav,id=id[,prop[=value][,...]]\n"
837 " path= path of wav file to record\n",
838 QEMU_ARCH_ALL)
839 SRST
840 ``-audiodev [driver=]driver,id=id[,prop[=value][,...]]``
841 Adds a new audio backend driver identified by id. There are global
842 and driver specific properties. Some values can be set differently
843 for input and output, they're marked with ``in|out.``. You can set
844 the input's property with ``in.prop`` and the output's property with
845 ``out.prop``. For example:
849 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
850 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
852 NOTE: parameter validation is known to be incomplete, in many cases
853 specifying an invalid option causes QEMU to print an error message
854 and continue emulation without sound.
856 Valid global options are:
858 ``id=identifier``
859 Identifies the audio backend.
861 ``timer-period=period``
862 Sets the timer period used by the audio subsystem in
863 microseconds. Default is 10000 (10 ms).
865 ``in|out.mixing-engine=on|off``
866 Use QEMU's mixing engine to mix all streams inside QEMU and
867 convert audio formats when not supported by the backend. When
868 off, fixed-settings must be off too. Note that disabling this
869 option means that the selected backend must support multiple
870 streams and the audio formats used by the virtual cards,
871 otherwise you'll get no sound. It's not recommended to disable
872 this option unless you want to use 5.1 or 7.1 audio, as mixing
873 engine only supports mono and stereo audio. Default is on.
875 ``in|out.fixed-settings=on|off``
876 Use fixed settings for host audio. When off, it will change
877 based on how the guest opens the sound card. In this case you
878 must not specify frequency, channels or format. Default is on.
880 ``in|out.frequency=frequency``
881 Specify the frequency to use when using fixed-settings. Default
882 is 44100Hz.
884 ``in|out.channels=channels``
885 Specify the number of channels to use when using fixed-settings.
886 Default is 2 (stereo).
888 ``in|out.format=format``
889 Specify the sample format to use when using fixed-settings.
890 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``,
891 ``u32``, ``f32``. Default is ``s16``.
893 ``in|out.voices=voices``
894 Specify the number of voices to use. Default is 1.
896 ``in|out.buffer-length=usecs``
897 Sets the size of the buffer in microseconds.
899 ``-audiodev none,id=id[,prop[=value][,...]]``
900 Creates a dummy backend that discards all outputs. This backend has
901 no backend specific properties.
903 ``-audiodev alsa,id=id[,prop[=value][,...]]``
904 Creates backend using the ALSA. This backend is only available on
905 Linux.
907 ALSA specific options are:
909 ``in|out.dev=device``
910 Specify the ALSA device to use for input and/or output. Default
911 is ``default``.
913 ``in|out.period-length=usecs``
914 Sets the period length in microseconds.
916 ``in|out.try-poll=on|off``
917 Attempt to use poll mode with the device. Default is on.
919 ``threshold=threshold``
920 Threshold (in microseconds) when playback starts. Default is 0.
922 ``-audiodev coreaudio,id=id[,prop[=value][,...]]``
923 Creates a backend using Apple's Core Audio. This backend is only
924 available on Mac OS and only supports playback.
926 Core Audio specific options are:
928 ``in|out.buffer-count=count``
929 Sets the count of the buffers.
931 ``-audiodev dsound,id=id[,prop[=value][,...]]``
932 Creates a backend using Microsoft's DirectSound. This backend is
933 only available on Windows and only supports playback.
935 DirectSound specific options are:
937 ``latency=usecs``
938 Add extra usecs microseconds latency to playback. Default is
939 10000 (10 ms).
941 ``-audiodev oss,id=id[,prop[=value][,...]]``
942 Creates a backend using OSS. This backend is available on most
943 Unix-like systems.
945 OSS specific options are:
947 ``in|out.dev=device``
948 Specify the file name of the OSS device to use. Default is
949 ``/dev/dsp``.
951 ``in|out.buffer-count=count``
952 Sets the count of the buffers.
954 ``in|out.try-poll=on|of``
955 Attempt to use poll mode with the device. Default is on.
957 ``try-mmap=on|off``
958 Try using memory mapped device access. Default is off.
960 ``exclusive=on|off``
961 Open the device in exclusive mode (vmix won't work in this
962 case). Default is off.
964 ``dsp-policy=policy``
965 Sets the timing policy (between 0 and 10, where smaller number
966 means smaller latency but higher CPU usage). Use -1 to use
967 buffer sizes specified by ``buffer`` and ``buffer-count``. This
968 option is ignored if you do not have OSS 4. Default is 5.
970 ``-audiodev pa,id=id[,prop[=value][,...]]``
971 Creates a backend using PulseAudio. This backend is available on
972 most systems.
974 PulseAudio specific options are:
976 ``server=server``
977 Sets the PulseAudio server to connect to.
979 ``in|out.name=sink``
980 Use the specified source/sink for recording/playback.
982 ``in|out.latency=usecs``
983 Desired latency in microseconds. The PulseAudio server will try
984 to honor this value but actual latencies may be lower or higher.
986 ``-audiodev pipewire,id=id[,prop[=value][,...]]``
987 Creates a backend using PipeWire. This backend is available on
988 most systems.
990 PipeWire specific options are:
992 ``in|out.latency=usecs``
993 Desired latency in microseconds.
995 ``in|out.name=sink``
996 Use the specified source/sink for recording/playback.
998 ``in|out.stream-name``
999 Specify the name of pipewire stream.
1001 ``-audiodev sdl,id=id[,prop[=value][,...]]``
1002 Creates a backend using SDL. This backend is available on most
1003 systems, but you should use your platform's native backend if
1004 possible.
1006 SDL specific options are:
1008 ``in|out.buffer-count=count``
1009 Sets the count of the buffers.
1011 ``-audiodev sndio,id=id[,prop[=value][,...]]``
1012 Creates a backend using SNDIO. This backend is available on
1013 OpenBSD and most other Unix-like systems.
1015 Sndio specific options are:
1017 ``in|out.dev=device``
1018 Specify the sndio device to use for input and/or output. Default
1019 is ``default``.
1021 ``in|out.latency=usecs``
1022 Sets the desired period length in microseconds.
1024 ``-audiodev spice,id=id[,prop[=value][,...]]``
1025 Creates a backend that sends audio through SPICE. This backend
1026 requires ``-spice`` and automatically selected in that case, so
1027 usually you can ignore this option. This backend has no backend
1028 specific properties.
1030 ``-audiodev wav,id=id[,prop[=value][,...]]``
1031 Creates a backend that writes audio to a WAV file.
1033 Backend specific options are:
1035 ``path=path``
1036 Write recorded audio into the specified file. Default is
1037 ``qemu.wav``.
1038 ERST
1040 DEF("device", HAS_ARG, QEMU_OPTION_device,
1041 "-device driver[,prop[=value][,...]]\n"
1042 " add device (based on driver)\n"
1043 " prop=value,... sets driver properties\n"
1044 " use '-device help' to print all possible drivers\n"
1045 " use '-device driver,help' to print all possible properties\n",
1046 QEMU_ARCH_ALL)
1047 SRST
1048 ``-device driver[,prop[=value][,...]]``
1049 Add device driver. prop=value sets driver properties. Valid
1050 properties depend on the driver. To get help on possible drivers and
1051 properties, use ``-device help`` and ``-device driver,help``.
1053 Some drivers are:
1055 ``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]``
1056 Add an IPMI BMC. This is a simulation of a hardware management
1057 interface processor that normally sits on a system. It provides a
1058 watchdog and the ability to reset and power control the system. You
1059 need to connect this to an IPMI interface to make it useful
1061 The IPMI slave address to use for the BMC. The default is 0x20. This
1062 address is the BMC's address on the I2C network of management
1063 controllers. If you don't know what this means, it is safe to ignore
1066 ``id=id``
1067 The BMC id for interfaces to use this device.
1069 ``slave_addr=val``
1070 Define slave address to use for the BMC. The default is 0x20.
1072 ``sdrfile=file``
1073 file containing raw Sensor Data Records (SDR) data. The default
1074 is none.
1076 ``fruareasize=val``
1077 size of a Field Replaceable Unit (FRU) area. The default is
1078 1024.
1080 ``frudatafile=file``
1081 file containing raw Field Replaceable Unit (FRU) inventory data.
1082 The default is none.
1084 ``guid=uuid``
1085 value for the GUID for the BMC, in standard UUID format. If this
1086 is set, get "Get GUID" command to the BMC will return it.
1087 Otherwise "Get GUID" will return an error.
1089 ``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]``
1090 Add a connection to an external IPMI BMC simulator. Instead of
1091 locally emulating the BMC like the above item, instead connect to an
1092 external entity that provides the IPMI services.
1094 A connection is made to an external BMC simulator. If you do this,
1095 it is strongly recommended that you use the "reconnect=" chardev
1096 option to reconnect to the simulator if the connection is lost. Note
1097 that if this is not used carefully, it can be a security issue, as
1098 the interface has the ability to send resets, NMIs, and power off
1099 the VM. It's best if QEMU makes a connection to an external
1100 simulator running on a secure port on localhost, so neither the
1101 simulator nor QEMU is exposed to any outside network.
1103 See the "lanserv/README.vm" file in the OpenIPMI library for more
1104 details on the external interface.
1106 ``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]``
1107 Add a KCS IPMI interface on the ISA bus. This also adds a
1108 corresponding ACPI and SMBIOS entries, if appropriate.
1110 ``bmc=id``
1111 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern
1112 above.
1114 ``ioport=val``
1115 Define the I/O address of the interface. The default is 0xca0
1116 for KCS.
1118 ``irq=val``
1119 Define the interrupt to use. The default is 5. To disable
1120 interrupts, set this to 0.
1122 ``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]``
1123 Like the KCS interface, but defines a BT interface. The default port
1124 is 0xe4 and the default interrupt is 5.
1126 ``-device pci-ipmi-kcs,bmc=id``
1127 Add a KCS IPMI interface on the PCI bus.
1129 ``bmc=id``
1130 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
1132 ``-device pci-ipmi-bt,bmc=id``
1133 Like the KCS interface, but defines a BT interface on the PCI bus.
1135 ``-device intel-iommu[,option=...]``
1136 This is only supported by ``-machine q35``, which will enable Intel VT-d
1137 emulation within the guest. It supports below options:
1139 ``intremap=on|off`` (default: auto)
1140 This enables interrupt remapping feature. It's required to enable
1141 complete x2apic. Currently it only supports kvm kernel-irqchip modes
1142 ``off`` or ``split``, while full kernel-irqchip is not yet supported.
1143 The default value is "auto", which will be decided by the mode of
1144 kernel-irqchip.
1146 ``caching-mode=on|off`` (default: off)
1147 This enables caching mode for the VT-d emulated device. When
1148 caching-mode is enabled, each guest DMA buffer mapping will generate an
1149 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in
1150 a synchronous way. It is required for ``-device vfio-pci`` to work
1151 with the VT-d device, because host assigned devices requires to setup
1152 the DMA mapping on the host before guest DMA starts.
1154 ``device-iotlb=on|off`` (default: off)
1155 This enables device-iotlb capability for the emulated VT-d device. So
1156 far virtio/vhost should be the only real user for this parameter,
1157 paired with ats=on configured for the device.
1159 ``aw-bits=39|48`` (default: 39)
1160 This decides the address width of IOVA address space. The address
1161 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for
1162 4-level IOMMU page tables.
1164 Please also refer to the wiki page for general scenarios of VT-d
1165 emulation in QEMU: https://wiki.qemu.org/Features/VT-d.
1167 ERST
1169 DEF("name", HAS_ARG, QEMU_OPTION_name,
1170 "-name string1[,process=string2][,debug-threads=on|off]\n"
1171 " set the name of the guest\n"
1172 " string1 sets the window title and string2 the process name\n"
1173 " When debug-threads is enabled, individual threads are given a separate name\n"
1174 " NOTE: The thread names are for debugging and not a stable API.\n",
1175 QEMU_ARCH_ALL)
1176 SRST
1177 ``-name name``
1178 Sets the name of the guest. This name will be displayed in the SDL
1179 window caption. The name will also be used for the VNC server. Also
1180 optionally set the top visible process name in Linux. Naming of
1181 individual threads can also be enabled on Linux to aid debugging.
1182 ERST
1184 DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
1185 "-uuid %08x-%04x-%04x-%04x-%012x\n"
1186 " specify machine UUID\n", QEMU_ARCH_ALL)
1187 SRST
1188 ``-uuid uuid``
1189 Set system UUID.
1190 ERST
1192 DEFHEADING()
1194 DEFHEADING(Block device options:)
1196 SRST
1197 The QEMU block device handling options have a long history and
1198 have gone through several iterations as the feature set and complexity
1199 of the block layer have grown. Many online guides to QEMU often
1200 reference older and deprecated options, which can lead to confusion.
1202 The most explicit way to describe disks is to use a combination of
1203 ``-device`` to specify the hardware device and ``-blockdev`` to
1204 describe the backend. The device defines what the guest sees and the
1205 backend describes how QEMU handles the data. It is the only guaranteed
1206 stable interface for describing block devices and as such is
1207 recommended for management tools and scripting.
1209 The ``-drive`` option combines the device and backend into a single
1210 command line option which is a more human friendly. There is however no
1211 interface stability guarantee although some older board models still
1212 need updating to work with the modern blockdev forms.
1214 Older options like ``-hda`` are essentially macros which expand into
1215 ``-drive`` options for various drive interfaces. The original forms
1216 bake in a lot of assumptions from the days when QEMU was emulating a
1217 legacy PC, they are not recommended for modern configurations.
1219 ERST
1221 DEF("fda", HAS_ARG, QEMU_OPTION_fda,
1222 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
1223 DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
1224 SRST
1225 ``-fda file``
1227 ``-fdb file``
1228 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in
1229 the System Emulation Users Guide).
1230 ERST
1232 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
1233 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL)
1234 DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
1235 DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
1236 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL)
1237 DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
1238 SRST
1239 ``-hda file``
1241 ``-hdb file``
1243 ``-hdc file``
1245 ``-hdd file``
1246 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the
1247 emulated machine (this is for example the IDE bus on most x86 machines,
1248 but it can also be SCSI, virtio or something else on other target
1249 architectures). See also the :ref:`disk images` chapter in the System
1250 Emulation Users Guide.
1251 ERST
1253 DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
1254 "-cdrom file use 'file' as CD-ROM image\n",
1255 QEMU_ARCH_ALL)
1256 SRST
1257 ``-cdrom file``
1258 Use file as CD-ROM image on the default bus of the emulated machine
1259 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom``
1260 at the same time there). On systems that support it, you can use the
1261 host CD-ROM by using ``/dev/cdrom`` as filename.
1262 ERST
1264 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
1265 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
1266 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
1267 " [,read-only=on|off][,auto-read-only=on|off]\n"
1268 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
1269 " [,driver specific parameters...]\n"
1270 " configure a block backend\n", QEMU_ARCH_ALL)
1271 SRST
1272 ``-blockdev option[,option[,option[,...]]]``
1273 Define a new block driver node. Some of the options apply to all
1274 block drivers, other options are only accepted for a specific block
1275 driver. See below for a list of generic options and options for the
1276 most common block drivers.
1278 Options that expect a reference to another node (e.g. ``file``) can
1279 be given in two ways. Either you specify the node name of an already
1280 existing node (file=node-name), or you define a new node inline,
1281 adding options for the referenced node after a dot
1282 (file.filename=path,file.aio=native).
1284 A block driver node created with ``-blockdev`` can be used for a
1285 guest device by specifying its node name for the ``drive`` property
1286 in a ``-device`` argument that defines a block device.
1288 ``Valid options for any block driver node:``
1289 ``driver``
1290 Specifies the block driver to use for the given node.
1292 ``node-name``
1293 This defines the name of the block driver node by which it
1294 will be referenced later. The name must be unique, i.e. it
1295 must not match the name of a different block driver node, or
1296 (if you use ``-drive`` as well) the ID of a drive.
1298 If no node name is specified, it is automatically generated.
1299 The generated node name is not intended to be predictable
1300 and changes between QEMU invocations. For the top level, an
1301 explicit node name must be specified.
1303 ``read-only``
1304 Open the node read-only. Guest write attempts will fail.
1306 Note that some block drivers support only read-only access,
1307 either generally or in certain configurations. In this case,
1308 the default value ``read-only=off`` does not work and the
1309 option must be specified explicitly.
1311 ``auto-read-only``
1312 If ``auto-read-only=on`` is set, QEMU may fall back to
1313 read-only usage even when ``read-only=off`` is requested, or
1314 even switch between modes as needed, e.g. depending on
1315 whether the image file is writable or whether a writing user
1316 is attached to the node.
1318 ``force-share``
1319 Override the image locking system of QEMU by forcing the
1320 node to utilize weaker shared access for permissions where
1321 it would normally request exclusive access. When there is
1322 the potential for multiple instances to have the same file
1323 open (whether this invocation of QEMU is the first or the
1324 second instance), both instances must permit shared access
1325 for the second instance to succeed at opening the file.
1327 Enabling ``force-share=on`` requires ``read-only=on``.
1329 ``cache.direct``
1330 The host page cache can be avoided with ``cache.direct=on``.
1331 This will attempt to do disk IO directly to the guest's
1332 memory. QEMU may still perform an internal copy of the data.
1334 ``cache.no-flush``
1335 In case you don't care about data integrity over host
1336 failures, you can use ``cache.no-flush=on``. This option
1337 tells QEMU that it never needs to write any data to the disk
1338 but can instead keep things in cache. If anything goes
1339 wrong, like your host losing power, the disk storage getting
1340 disconnected accidentally, etc. your image will most
1341 probably be rendered unusable.
1343 ``discard=discard``
1344 discard is one of "ignore" (or "off") or "unmap" (or "on")
1345 and controls whether ``discard`` (also known as ``trim`` or
1346 ``unmap``) requests are ignored or passed to the filesystem.
1347 Some machine types may not support discard requests.
1349 ``detect-zeroes=detect-zeroes``
1350 detect-zeroes is "off", "on" or "unmap" and enables the
1351 automatic conversion of plain zero writes by the OS to
1352 driver specific optimized zero write commands. You may even
1353 choose "unmap" if discard is set to "unmap" to allow a zero
1354 write to be converted to an ``unmap`` operation.
1356 ``Driver-specific options for file``
1357 This is the protocol-level block driver for accessing regular
1358 files.
1360 ``filename``
1361 The path to the image file in the local filesystem
1363 ``aio``
1364 Specifies the AIO backend (threads/native/io_uring,
1365 default: threads)
1367 ``locking``
1368 Specifies whether the image file is protected with Linux OFD
1369 / POSIX locks. The default is to use the Linux Open File
1370 Descriptor API if available, otherwise no lock is applied.
1371 (auto/on/off, default: auto)
1373 Example:
1377 -blockdev driver=file,node-name=disk,filename=disk.img
1379 ``Driver-specific options for raw``
1380 This is the image format block driver for raw images. It is
1381 usually stacked on top of a protocol level block driver such as
1382 ``file``.
1384 ``file``
1385 Reference to or definition of the data source block driver
1386 node (e.g. a ``file`` driver node)
1388 Example 1:
1392 -blockdev driver=file,node-name=disk_file,filename=disk.img
1393 -blockdev driver=raw,node-name=disk,file=disk_file
1395 Example 2:
1399 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1401 ``Driver-specific options for qcow2``
1402 This is the image format block driver for qcow2 images. It is
1403 usually stacked on top of a protocol level block driver such as
1404 ``file``.
1406 ``file``
1407 Reference to or definition of the data source block driver
1408 node (e.g. a ``file`` driver node)
1410 ``backing``
1411 Reference to or definition of the backing file block device
1412 (default is taken from the image file). It is allowed to
1413 pass ``null`` here in order to disable the default backing
1414 file.
1416 ``lazy-refcounts``
1417 Whether to enable the lazy refcounts feature (on/off;
1418 default is taken from the image file)
1420 ``cache-size``
1421 The maximum total size of the L2 table and refcount block
1422 caches in bytes (default: the sum of l2-cache-size and
1423 refcount-cache-size)
1425 ``l2-cache-size``
1426 The maximum size of the L2 table cache in bytes (default: if
1427 cache-size is not specified - 32M on Linux platforms, and 8M
1428 on non-Linux platforms; otherwise, as large as possible
1429 within the cache-size, while permitting the requested or the
1430 minimal refcount cache size)
1432 ``refcount-cache-size``
1433 The maximum size of the refcount block cache in bytes
1434 (default: 4 times the cluster size; or if cache-size is
1435 specified, the part of it which is not used for the L2
1436 cache)
1438 ``cache-clean-interval``
1439 Clean unused entries in the L2 and refcount caches. The
1440 interval is in seconds. The default value is 600 on
1441 supporting platforms, and 0 on other platforms. Setting it
1442 to 0 disables this feature.
1444 ``pass-discard-request``
1445 Whether discard requests to the qcow2 device should be
1446 forwarded to the data source (on/off; default: on if
1447 discard=unmap is specified, off otherwise)
1449 ``pass-discard-snapshot``
1450 Whether discard requests for the data source should be
1451 issued when a snapshot operation (e.g. deleting a snapshot)
1452 frees clusters in the qcow2 file (on/off; default: on)
1454 ``pass-discard-other``
1455 Whether discard requests for the data source should be
1456 issued on other occasions where a cluster gets freed
1457 (on/off; default: off)
1459 ``discard-no-unref``
1460 When enabled, discards from the guest will not cause cluster
1461 allocations to be relinquished. This prevents qcow2 fragmentation
1462 that would be caused by such discards. Besides potential
1463 performance degradation, such fragmentation can lead to increased
1464 allocation of clusters past the end of the image file,
1465 resulting in image files whose file length can grow much larger
1466 than their guest disk size would suggest.
1467 If image file length is of concern (e.g. when storing qcow2
1468 images directly on block devices), you should consider enabling
1469 this option.
1471 ``overlap-check``
1472 Which overlap checks to perform for writes to the image
1473 (none/constant/cached/all; default: cached). For details or
1474 finer granularity control refer to the QAPI documentation of
1475 ``blockdev-add``.
1477 Example 1:
1481 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1482 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1484 Example 2:
1488 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1490 ``Driver-specific options for other drivers``
1491 Please refer to the QAPI documentation of the ``blockdev-add``
1492 QMP command.
1493 ERST
1495 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1496 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1497 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1498 " [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1499 " [,werror=ignore|stop|report|enospc][,id=name]\n"
1500 " [,aio=threads|native|io_uring]\n"
1501 " [,readonly=on|off][,copy-on-read=on|off]\n"
1502 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1503 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1504 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1505 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1506 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1507 " [[,iops_size=is]]\n"
1508 " [[,group=g]]\n"
1509 " use 'file' as a drive image\n", QEMU_ARCH_ALL)
1510 SRST
1511 ``-drive option[,option[,option[,...]]]``
1512 Define a new drive. This includes creating a block driver node (the
1513 backend) as well as a guest device, and is mostly a shortcut for
1514 defining the corresponding ``-blockdev`` and ``-device`` options.
1516 ``-drive`` accepts all options that are accepted by ``-blockdev``.
1517 In addition, it knows the following options:
1519 ``file=file``
1520 This option defines which disk image (see the :ref:`disk images`
1521 chapter in the System Emulation Users Guide) to use with this drive.
1522 If the filename contains comma, you must double it (for instance,
1523 "file=my,,file" to use file "my,file").
1525 Special files such as iSCSI devices can be specified using
1526 protocol specific URLs. See the section for "Device URL Syntax"
1527 for more information.
1529 ``if=interface``
1530 This option defines on which type on interface the drive is
1531 connected. Available types are: ide, scsi, sd, mtd, floppy,
1532 pflash, virtio, none.
1534 ``bus=bus,unit=unit``
1535 These options define where is connected the drive by defining
1536 the bus number and the unit id.
1538 ``index=index``
1539 This option defines where the drive is connected by using an
1540 index in the list of available connectors of a given interface
1541 type.
1543 ``media=media``
1544 This option defines the type of the media: disk or cdrom.
1546 ``snapshot=snapshot``
1547 snapshot is "on" or "off" and controls snapshot mode for the
1548 given drive (see ``-snapshot``).
1550 ``cache=cache``
1551 cache is "none", "writeback", "unsafe", "directsync" or
1552 "writethrough" and controls how the host cache is used to access
1553 block data. This is a shortcut that sets the ``cache.direct``
1554 and ``cache.no-flush`` options (as in ``-blockdev``), and
1555 additionally ``cache.writeback``, which provides a default for
1556 the ``write-cache`` option of block guest devices (as in
1557 ``-device``). The modes correspond to the following settings:
1559 ============= =============== ============ ==============
1560 \ cache.writeback cache.direct cache.no-flush
1561 ============= =============== ============ ==============
1562 writeback on off off
1563 none on on off
1564 writethrough off off off
1565 directsync off on off
1566 unsafe on off on
1567 ============= =============== ============ ==============
1569 The default mode is ``cache=writeback``.
1571 ``aio=aio``
1572 aio is "threads", "native", or "io_uring" and selects between pthread
1573 based disk I/O, native Linux AIO, or Linux io_uring API.
1575 ``format=format``
1576 Specify which disk format will be used rather than detecting the
1577 format. Can be used to specify format=raw to avoid interpreting
1578 an untrusted format header.
1580 ``werror=action,rerror=action``
1581 Specify which action to take on write and read errors. Valid
1582 actions are: "ignore" (ignore the error and try to continue),
1583 "stop" (pause QEMU), "report" (report the error to the guest),
1584 "enospc" (pause QEMU only if the host disk is full; report the
1585 error to the guest otherwise). The default setting is
1586 ``werror=enospc`` and ``rerror=report``.
1588 ``copy-on-read=copy-on-read``
1589 copy-on-read is "on" or "off" and enables whether to copy read
1590 backing file sectors into the image file.
1592 ``bps=b,bps_rd=r,bps_wr=w``
1593 Specify bandwidth throttling limits in bytes per second, either
1594 for all request types or for reads or writes only. Small values
1595 can lead to timeouts or hangs inside the guest. A safe minimum
1596 for disks is 2 MB/s.
1598 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm``
1599 Specify bursts in bytes per second, either for all request types
1600 or for reads or writes only. Bursts allow the guest I/O to spike
1601 above the limit temporarily.
1603 ``iops=i,iops_rd=r,iops_wr=w``
1604 Specify request rate limits in requests per second, either for
1605 all request types or for reads or writes only.
1607 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm``
1608 Specify bursts in requests per second, either for all request
1609 types or for reads or writes only. Bursts allow the guest I/O to
1610 spike above the limit temporarily.
1612 ``iops_size=is``
1613 Let every is bytes of a request count as a new request for iops
1614 throttling purposes. Use this option to prevent guests from
1615 circumventing iops limits by sending fewer but larger requests.
1617 ``group=g``
1618 Join a throttling quota group with given name g. All drives that
1619 are members of the same group are accounted for together. Use
1620 this option to prevent guests from circumventing throttling
1621 limits by using many small disks instead of a single larger
1622 disk.
1624 By default, the ``cache.writeback=on`` mode is used. It will report
1625 data writes as completed as soon as the data is present in the host
1626 page cache. This is safe as long as your guest OS makes sure to
1627 correctly flush disk caches where needed. If your guest OS does not
1628 handle volatile disk write caches correctly and your host crashes or
1629 loses power, then the guest may experience data corruption.
1631 For such guests, you should consider using ``cache.writeback=off``.
1632 This means that the host page cache will be used to read and write
1633 data, but write notification will be sent to the guest only after
1634 QEMU has made sure to flush each write to the disk. Be aware that
1635 this has a major impact on performance.
1637 When using the ``-snapshot`` option, unsafe caching is always used.
1639 Copy-on-read avoids accessing the same backing file sectors
1640 repeatedly and is useful when the backing file is over a slow
1641 network. By default copy-on-read is off.
1643 Instead of ``-cdrom`` you can use:
1645 .. parsed-literal::
1647 |qemu_system| -drive file=file,index=2,media=cdrom
1649 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use:
1651 .. parsed-literal::
1653 |qemu_system| -drive file=file,index=0,media=disk
1654 |qemu_system| -drive file=file,index=1,media=disk
1655 |qemu_system| -drive file=file,index=2,media=disk
1656 |qemu_system| -drive file=file,index=3,media=disk
1658 You can open an image using pre-opened file descriptors from an fd
1659 set:
1661 .. parsed-literal::
1663 |qemu_system| \\
1664 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
1665 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
1666 -drive file=/dev/fdset/2,index=0,media=disk
1668 You can connect a CDROM to the slave of ide0:
1670 .. parsed-literal::
1672 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom
1674 If you don't specify the "file=" argument, you define an empty
1675 drive:
1677 .. parsed-literal::
1679 |qemu_system_x86| -drive if=ide,index=1,media=cdrom
1681 Instead of ``-fda``, ``-fdb``, you can use:
1683 .. parsed-literal::
1685 |qemu_system_x86| -drive file=file,index=0,if=floppy
1686 |qemu_system_x86| -drive file=file,index=1,if=floppy
1688 By default, interface is "ide" and index is automatically
1689 incremented:
1691 .. parsed-literal::
1693 |qemu_system_x86| -drive file=a -drive file=b
1695 is interpreted like:
1697 .. parsed-literal::
1699 |qemu_system_x86| -hda a -hdb b
1700 ERST
1702 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1703 "-mtdblock file use 'file' as on-board Flash memory image\n",
1704 QEMU_ARCH_ALL)
1705 SRST
1706 ``-mtdblock file``
1707 Use file as on-board Flash memory image.
1708 ERST
1710 DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1711 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1712 SRST
1713 ``-sd file``
1714 Use file as SecureDigital card image.
1715 ERST
1717 DEF("snapshot", 0, QEMU_OPTION_snapshot,
1718 "-snapshot write to temporary files instead of disk image files\n",
1719 QEMU_ARCH_ALL)
1720 SRST
1721 ``-snapshot``
1722 Write to temporary files instead of disk image files. In this case,
1723 the raw disk image you use is not written back. You can however
1724 force the write back by pressing C-a s (see the :ref:`disk images`
1725 chapter in the System Emulation Users Guide).
1727 .. warning::
1728 snapshot is incompatible with ``-blockdev`` (instead use qemu-img
1729 to manually create snapshot images to attach to your blockdev).
1730 If you have mixed ``-blockdev`` and ``-drive`` declarations you
1731 can use the 'snapshot' property on your drive declarations
1732 instead of this global option.
1734 ERST
1736 DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1737 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1738 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n"
1739 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1740 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1741 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1742 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1743 " [[,throttling.iops-size=is]]\n"
1744 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n"
1745 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n"
1746 "-fsdev synth,id=id\n",
1747 QEMU_ARCH_ALL)
1749 SRST
1750 ``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]``
1752 ``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]``
1754 ``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]``
1756 ``-fsdev synth,id=id[,readonly=on]``
1757 Define a new file system device. Valid options are:
1759 ``local``
1760 Accesses to the filesystem are done by QEMU.
1762 ``proxy``
1763 Accesses to the filesystem are done by virtfs-proxy-helper(1). This
1764 option is deprecated (since QEMU 8.1) and will be removed in a future
1765 version of QEMU. Use ``local`` instead.
1767 ``synth``
1768 Synthetic filesystem, only used by QTests.
1770 ``id=id``
1771 Specifies identifier for this device.
1773 ``path=path``
1774 Specifies the export path for the file system device. Files
1775 under this path will be available to the 9p client on the guest.
1777 ``security_model=security_model``
1778 Specifies the security model to be used for this export path.
1779 Supported security models are "passthrough", "mapped-xattr",
1780 "mapped-file" and "none". In "passthrough" security model, files
1781 are stored using the same credentials as they are created on the
1782 guest. This requires QEMU to run as root. In "mapped-xattr"
1783 security model, some of the file attributes like uid, gid, mode
1784 bits and link target are stored as file attributes. For
1785 "mapped-file" these attributes are stored in the hidden
1786 .virtfs\_metadata directory. Directories exported by this
1787 security model cannot interact with other unix tools. "none"
1788 security model is same as passthrough except the sever won't
1789 report failures if it fails to set file attributes like
1790 ownership. Security model is mandatory only for local fsdriver.
1791 Other fsdrivers (like proxy) don't take security model as a
1792 parameter.
1794 ``writeout=writeout``
1795 This is an optional argument. The only supported value is
1796 "immediate". This means that host page cache will be used to
1797 read and write data but write notification will be sent to the
1798 guest only when the data has been reported as written by the
1799 storage subsystem.
1801 ``readonly=on``
1802 Enables exporting 9p share as a readonly mount for guests. By
1803 default read-write access is given.
1805 ``socket=socket``
1806 Enables proxy filesystem driver to use passed socket file for
1807 communicating with virtfs-proxy-helper(1).
1809 ``sock_fd=sock_fd``
1810 Enables proxy filesystem driver to use passed socket descriptor
1811 for communicating with virtfs-proxy-helper(1). Usually a helper
1812 like libvirt will create socketpair and pass one of the fds as
1813 sock\_fd.
1815 ``fmode=fmode``
1816 Specifies the default mode for newly created files on the host.
1817 Works only with security models "mapped-xattr" and
1818 "mapped-file".
1820 ``dmode=dmode``
1821 Specifies the default mode for newly created directories on the
1822 host. Works only with security models "mapped-xattr" and
1823 "mapped-file".
1825 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w``
1826 Specify bandwidth throttling limits in bytes per second, either
1827 for all request types or for reads or writes only.
1829 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm``
1830 Specify bursts in bytes per second, either for all request types
1831 or for reads or writes only. Bursts allow the guest I/O to spike
1832 above the limit temporarily.
1834 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w``
1835 Specify request rate limits in requests per second, either for
1836 all request types or for reads or writes only.
1838 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm``
1839 Specify bursts in requests per second, either for all request
1840 types or for reads or writes only. Bursts allow the guest I/O to
1841 spike above the limit temporarily.
1843 ``throttling.iops-size=is``
1844 Let every is bytes of a request count as a new request for iops
1845 throttling purposes.
1847 -fsdev option is used along with -device driver "virtio-9p-...".
1849 ``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag``
1850 Options for virtio-9p-... driver are:
1852 ``type``
1853 Specifies the variant to be used. Supported values are "pci",
1854 "ccw" or "device", depending on the machine type.
1856 ``fsdev=id``
1857 Specifies the id value specified along with -fsdev option.
1859 ``mount_tag=mount_tag``
1860 Specifies the tag name to be used by the guest to mount this
1861 export point.
1862 ERST
1864 DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1865 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1866 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n"
1867 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n"
1868 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n"
1869 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n",
1870 QEMU_ARCH_ALL)
1872 SRST
1873 ``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]``
1875 ``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1877 ``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1879 ``-virtfs synth,mount_tag=mount_tag``
1880 Define a new virtual filesystem device and expose it to the guest using
1881 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain
1882 directory on host is made directly accessible by guest as a pass-through
1883 file system by using the 9P network protocol for communication between
1884 host and guests, if desired even accessible, shared by several guests
1885 simultaneously.
1887 Note that ``-virtfs`` is actually just a convenience shortcut for its
1888 generalized form ``-fsdev -device virtio-9p-pci``.
1890 The general form of pass-through file system options are:
1892 ``local``
1893 Accesses to the filesystem are done by QEMU.
1895 ``proxy``
1896 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1897 This option is deprecated (since QEMU 8.1) and will be removed in a
1898 future version of QEMU. Use ``local`` instead.
1900 ``synth``
1901 Synthetic filesystem, only used by QTests.
1903 ``id=id``
1904 Specifies identifier for the filesystem device
1906 ``path=path``
1907 Specifies the export path for the file system device. Files
1908 under this path will be available to the 9p client on the guest.
1910 ``security_model=security_model``
1911 Specifies the security model to be used for this export path.
1912 Supported security models are "passthrough", "mapped-xattr",
1913 "mapped-file" and "none". In "passthrough" security model, files
1914 are stored using the same credentials as they are created on the
1915 guest. This requires QEMU to run as root. In "mapped-xattr"
1916 security model, some of the file attributes like uid, gid, mode
1917 bits and link target are stored as file attributes. For
1918 "mapped-file" these attributes are stored in the hidden
1919 .virtfs\_metadata directory. Directories exported by this
1920 security model cannot interact with other unix tools. "none"
1921 security model is same as passthrough except the sever won't
1922 report failures if it fails to set file attributes like
1923 ownership. Security model is mandatory only for local fsdriver.
1924 Other fsdrivers (like proxy) don't take security model as a
1925 parameter.
1927 ``writeout=writeout``
1928 This is an optional argument. The only supported value is
1929 "immediate". This means that host page cache will be used to
1930 read and write data but write notification will be sent to the
1931 guest only when the data has been reported as written by the
1932 storage subsystem.
1934 ``readonly=on``
1935 Enables exporting 9p share as a readonly mount for guests. By
1936 default read-write access is given.
1938 ``socket=socket``
1939 Enables proxy filesystem driver to use passed socket file for
1940 communicating with virtfs-proxy-helper(1). Usually a helper like
1941 libvirt will create socketpair and pass one of the fds as
1942 sock\_fd.
1944 ``sock_fd``
1945 Enables proxy filesystem driver to use passed 'sock\_fd' as the
1946 socket descriptor for interfacing with virtfs-proxy-helper(1).
1948 ``fmode=fmode``
1949 Specifies the default mode for newly created files on the host.
1950 Works only with security models "mapped-xattr" and
1951 "mapped-file".
1953 ``dmode=dmode``
1954 Specifies the default mode for newly created directories on the
1955 host. Works only with security models "mapped-xattr" and
1956 "mapped-file".
1958 ``mount_tag=mount_tag``
1959 Specifies the tag name to be used by the guest to mount this
1960 export point.
1962 ``multidevs=multidevs``
1963 Specifies how to deal with multiple devices being shared with a
1964 9p export. Supported behaviours are either "remap", "forbid" or
1965 "warn". The latter is the default behaviour on which virtfs 9p
1966 expects only one device to be shared with the same export, and
1967 if more than one device is shared and accessed via the same 9p
1968 export then only a warning message is logged (once) by qemu on
1969 host side. In order to avoid file ID collisions on guest you
1970 should either create a separate virtfs export for each device to
1971 be shared with guests (recommended way) or you might use "remap"
1972 instead which allows you to share multiple devices with only one
1973 export instead, which is achieved by remapping the original
1974 inode numbers from host to guest in a way that would prevent
1975 such collisions. Remapping inodes in such use cases is required
1976 because the original device IDs from host are never passed and
1977 exposed on guest. Instead all files of an export shared with
1978 virtfs always share the same device id on guest. So two files
1979 with identical inode numbers but from actually different devices
1980 on host would otherwise cause a file ID collision and hence
1981 potential misbehaviours on guest. "forbid" on the other hand
1982 assumes like "warn" that only one device is shared by the same
1983 export, however it will not only log a warning message but also
1984 deny access to additional devices on guest. Note though that
1985 "forbid" does currently not block all possible file access
1986 operations (e.g. readdir() would still return entries from other
1987 devices).
1988 ERST
1990 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1991 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n"
1992 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n"
1993 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1994 " [,timeout=timeout]\n"
1995 " iSCSI session parameters\n", QEMU_ARCH_ALL)
1997 SRST
1998 ``-iscsi``
1999 Configure iSCSI session parameters.
2000 ERST
2002 DEFHEADING()
2004 DEFHEADING(USB convenience options:)
2006 DEF("usb", 0, QEMU_OPTION_usb,
2007 "-usb enable on-board USB host controller (if not enabled by default)\n",
2008 QEMU_ARCH_ALL)
2009 SRST
2010 ``-usb``
2011 Enable USB emulation on machine types with an on-board USB host
2012 controller (if not enabled by default). Note that on-board USB host
2013 controllers may not support USB 3.0. In this case
2014 ``-device qemu-xhci`` can be used instead on machines with PCI.
2015 ERST
2017 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
2018 "-usbdevice name add the host or guest USB device 'name'\n",
2019 QEMU_ARCH_ALL)
2020 SRST
2021 ``-usbdevice devname``
2022 Add the USB device devname, and enable an on-board USB controller
2023 if possible and necessary (just like it can be done via
2024 ``-machine usb=on``). Note that this option is mainly intended for
2025 the user's convenience only. More fine-grained control can be
2026 achieved by selecting a USB host controller (if necessary) and the
2027 desired USB device via the ``-device`` option instead. For example,
2028 instead of using ``-usbdevice mouse`` it is possible to use
2029 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse
2030 to a USB 3.0 controller instead (at least on machines that support
2031 PCI and do not have an USB controller enabled by default yet).
2032 For more details, see the chapter about
2033 :ref:`Connecting USB devices` in the System Emulation Users Guide.
2034 Possible devices for devname are:
2036 ``braille``
2037 Braille device. This will use BrlAPI to display the braille
2038 output on a real or fake device (i.e. it also creates a
2039 corresponding ``braille`` chardev automatically beside the
2040 ``usb-braille`` USB device).
2042 ``keyboard``
2043 Standard USB keyboard. Will override the PS/2 keyboard (if present).
2045 ``mouse``
2046 Virtual Mouse. This will override the PS/2 mouse emulation when
2047 activated.
2049 ``tablet``
2050 Pointer device that uses absolute coordinates (like a
2051 touchscreen). This means QEMU is able to report the mouse
2052 position without having to grab the mouse. Also overrides the
2053 PS/2 mouse emulation when activated.
2055 ``wacom-tablet``
2056 Wacom PenPartner USB tablet.
2059 ERST
2061 DEFHEADING()
2063 DEFHEADING(Display options:)
2065 DEF("display", HAS_ARG, QEMU_OPTION_display,
2066 #if defined(CONFIG_SPICE)
2067 "-display spice-app[,gl=on|off]\n"
2068 #endif
2069 #if defined(CONFIG_SDL)
2070 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n"
2071 " [,window-close=on|off]\n"
2072 #endif
2073 #if defined(CONFIG_GTK)
2074 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n"
2075 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n"
2076 " [,show-menubar=on|off]\n"
2077 #endif
2078 #if defined(CONFIG_VNC)
2079 "-display vnc=<display>[,<optargs>]\n"
2080 #endif
2081 #if defined(CONFIG_CURSES)
2082 "-display curses[,charset=<encoding>]\n"
2083 #endif
2084 #if defined(CONFIG_COCOA)
2085 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n"
2086 #endif
2087 #if defined(CONFIG_OPENGL)
2088 "-display egl-headless[,rendernode=<file>]\n"
2089 #endif
2090 #if defined(CONFIG_DBUS_DISPLAY)
2091 "-display dbus[,addr=<dbusaddr>]\n"
2092 " [,gl=on|core|es|off][,rendernode=<file>]\n"
2093 #endif
2094 #if defined(CONFIG_COCOA)
2095 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n"
2096 #endif
2097 "-display none\n"
2098 " select display backend type\n"
2099 " The default display is equivalent to\n "
2100 #if defined(CONFIG_GTK)
2101 "\"-display gtk\"\n"
2102 #elif defined(CONFIG_SDL)
2103 "\"-display sdl\"\n"
2104 #elif defined(CONFIG_COCOA)
2105 "\"-display cocoa\"\n"
2106 #elif defined(CONFIG_VNC)
2107 "\"-vnc localhost:0,to=99,id=default\"\n"
2108 #else
2109 "\"-display none\"\n"
2110 #endif
2111 , QEMU_ARCH_ALL)
2112 SRST
2113 ``-display type``
2114 Select type of display to use. Use ``-display help`` to list the available
2115 display types. Valid values for type are
2117 ``spice-app[,gl=on|off]``
2118 Start QEMU as a Spice server and launch the default Spice client
2119 application. The Spice server will redirect the serial consoles
2120 and QEMU monitors. (Since 4.0)
2122 ``dbus``
2123 Export the display over D-Bus interfaces. (Since 7.0)
2125 The connection is registered with the "org.qemu" name (and queued when
2126 already owned).
2128 ``addr=<dbusaddr>`` : D-Bus bus address to connect to.
2130 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``.
2132 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface
2133 will share framebuffers with DMABUF file descriptors).
2135 ``sdl``
2136 Display video output via SDL (usually in a separate graphics
2137 window; see the SDL documentation for other possibilities).
2138 Valid parameters are:
2140 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling
2141 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be
2142 either ``lshift-lctrl-lalt`` or ``rctrl``.
2144 ``gl=on|off|core|es`` : Use OpenGL for displaying
2146 ``show-cursor=on|off`` : Force showing the mouse cursor
2148 ``window-close=on|off`` : Allow to quit qemu with window close button
2150 ``gtk``
2151 Display video output in a GTK window. This interface provides
2152 drop-down menus and other UI elements to configure and control
2153 the VM during runtime. Valid parameters are:
2155 ``full-screen=on|off`` : Start in fullscreen mode
2157 ``gl=on|off`` : Use OpenGL for displaying
2159 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover
2161 ``show-tabs=on|off`` : Display the tab bar for switching between the
2162 various graphical interfaces (e.g. VGA and
2163 virtual console character devices) by default.
2165 ``show-cursor=on|off`` : Force showing the mouse cursor
2167 ``window-close=on|off`` : Allow to quit qemu with window close button
2169 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on"
2171 ``zoom-to-fit=on|off`` : Expand video output to the window size,
2172 defaults to "off"
2174 ``curses[,charset=<encoding>]``
2175 Display video output via curses. For graphics device models
2176 which support a text mode, QEMU can display this output using a
2177 curses/ncurses interface. Nothing is displayed when the graphics
2178 device is in graphical mode or if the graphics device does not
2179 support a text mode. Generally only the VGA device models
2180 support text mode. The font charset used by the guest can be
2181 specified with the ``charset`` option, for example
2182 ``charset=CP850`` for IBM CP850 encoding. The default is
2183 ``CP437``.
2185 ``cocoa``
2186 Display video output in a Cocoa window. Mac only. This interface
2187 provides drop-down menus and other UI elements to configure and
2188 control the VM during runtime. Valid parameters are:
2190 ``show-cursor=on|off`` : Force showing the mouse cursor
2192 ``left-command-key=on|off`` : Disable forwarding left command key to host
2194 ``egl-headless[,rendernode=<file>]``
2195 Offload all OpenGL operations to a local DRI device. For any
2196 graphical display, this display needs to be paired with either
2197 VNC or SPICE displays.
2199 ``vnc=<display>``
2200 Start a VNC server on display <display>
2202 ``none``
2203 Do not display video output. The guest will still see an
2204 emulated graphics card, but its output will not be displayed to
2205 the QEMU user. This option differs from the -nographic option in
2206 that it only affects what is done with video output; -nographic
2207 also changes the destination of the serial and parallel port
2208 data.
2209 ERST
2211 DEF("nographic", 0, QEMU_OPTION_nographic,
2212 "-nographic disable graphical output and redirect serial I/Os to console\n",
2213 QEMU_ARCH_ALL)
2214 SRST
2215 ``-nographic``
2216 Normally, if QEMU is compiled with graphical window support, it
2217 displays output such as guest graphics, guest console, and the QEMU
2218 monitor in a window. With this option, you can totally disable
2219 graphical output so that QEMU is a simple command line application.
2220 The emulated serial port is redirected on the console and muxed with
2221 the monitor (unless redirected elsewhere explicitly). Therefore, you
2222 can still use QEMU to debug a Linux kernel with a serial console.
2223 Use C-a h for help on switching between the console and monitor.
2224 ERST
2226 #ifdef CONFIG_SPICE
2227 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
2228 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
2229 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
2230 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
2231 " [,x509-dh-key-file=<file>][,addr=addr]\n"
2232 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n"
2233 " [,tls-ciphers=<list>]\n"
2234 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
2235 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
2236 " [,sasl=on|off][,disable-ticketing=on|off]\n"
2237 " [,password-secret=<secret-id>]\n"
2238 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
2239 " [,jpeg-wan-compression=[auto|never|always]]\n"
2240 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
2241 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
2242 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
2243 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
2244 " [,gl=[on|off]][,rendernode=<file>]\n"
2245 " enable spice\n"
2246 " at least one of {port, tls-port} is mandatory\n",
2247 QEMU_ARCH_ALL)
2248 #endif
2249 SRST
2250 ``-spice option[,option[,...]]``
2251 Enable the spice remote desktop protocol. Valid options are
2253 ``port=<nr>``
2254 Set the TCP port spice is listening on for plaintext channels.
2256 ``addr=<addr>``
2257 Set the IP address spice is listening on. Default is any
2258 address.
2260 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off``
2261 Force using the specified IP version.
2263 ``password-secret=<secret-id>``
2264 Set the ID of the ``secret`` object containing the password
2265 you need to authenticate.
2267 ``sasl=on|off``
2268 Require that the client use SASL to authenticate with the spice.
2269 The exact choice of authentication method used is controlled
2270 from the system / user's SASL configuration file for the 'qemu'
2271 service. This is typically found in /etc/sasl2/qemu.conf. If
2272 running QEMU as an unprivileged user, an environment variable
2273 SASL\_CONF\_PATH can be used to make it search alternate
2274 locations for the service config. While some SASL auth methods
2275 can also provide data encryption (eg GSSAPI), it is recommended
2276 that SASL always be combined with the 'tls' and 'x509' settings
2277 to enable use of SSL and server certificates. This ensures a
2278 data encryption preventing compromise of authentication
2279 credentials.
2281 ``disable-ticketing=on|off``
2282 Allow client connects without authentication.
2284 ``disable-copy-paste=on|off``
2285 Disable copy paste between the client and the guest.
2287 ``disable-agent-file-xfer=on|off``
2288 Disable spice-vdagent based file-xfer between the client and the
2289 guest.
2291 ``tls-port=<nr>``
2292 Set the TCP port spice is listening on for encrypted channels.
2294 ``x509-dir=<dir>``
2295 Set the x509 file directory. Expects same filenames as -vnc
2296 $display,x509=$dir
2298 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>``
2299 The x509 file names can also be configured individually.
2301 ``tls-ciphers=<list>``
2302 Specify which ciphers to use.
2304 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]``
2305 Force specific channel to be used with or without TLS
2306 encryption. The options can be specified multiple times to
2307 configure multiple channels. The special name "default" can be
2308 used to set the default mode. For channels which are not
2309 explicitly forced into one mode the spice client is allowed to
2310 pick tls/plaintext as he pleases.
2312 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]``
2313 Configure image compression (lossless). Default is auto\_glz.
2315 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]``
2316 Configure wan image compression (lossy for slow links). Default
2317 is auto.
2319 ``streaming-video=[off|all|filter]``
2320 Configure video stream detection. Default is off.
2322 ``agent-mouse=[on|off]``
2323 Enable/disable passing mouse events via vdagent. Default is on.
2325 ``playback-compression=[on|off]``
2326 Enable/disable audio stream compression (using celt 0.5.1).
2327 Default is on.
2329 ``seamless-migration=[on|off]``
2330 Enable/disable spice seamless migration. Default is off.
2332 ``gl=[on|off]``
2333 Enable/disable OpenGL context. Default is off.
2335 ``rendernode=<file>``
2336 DRM render node for OpenGL rendering. If not specified, it will
2337 pick the first available. (Since 2.9)
2338 ERST
2340 DEF("portrait", 0, QEMU_OPTION_portrait,
2341 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
2342 QEMU_ARCH_ALL)
2343 SRST
2344 ``-portrait``
2345 Rotate graphical output 90 deg left (only PXA LCD).
2346 ERST
2348 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
2349 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
2350 QEMU_ARCH_ALL)
2351 SRST
2352 ``-rotate deg``
2353 Rotate graphical output some deg left (only PXA LCD).
2354 ERST
2356 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
2357 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
2358 " select video card type\n", QEMU_ARCH_ALL)
2359 SRST
2360 ``-vga type``
2361 Select type of VGA card to emulate. Valid values for type are
2363 ``cirrus``
2364 Cirrus Logic GD5446 Video card. All Windows versions starting
2365 from Windows 95 should recognize and use this graphic card. For
2366 optimal performances, use 16 bit color depth in the guest and
2367 the host OS. (This card was the default before QEMU 2.2)
2369 ``std``
2370 Standard VGA card with Bochs VBE extensions. If your guest OS
2371 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if
2372 you want to use high resolution modes (>= 1280x1024x16) then you
2373 should use this option. (This card is the default since QEMU
2374 2.2)
2376 ``vmware``
2377 VMWare SVGA-II compatible adapter. Use it if you have
2378 sufficiently recent XFree86/XOrg server or Windows guest with a
2379 driver for this card.
2381 ``qxl``
2382 QXL paravirtual graphic card. It is VGA compatible (including
2383 VESA 2.0 VBE support). Works best with qxl guest drivers
2384 installed though. Recommended choice when using the spice
2385 protocol.
2387 ``tcx``
2388 (sun4m only) Sun TCX framebuffer. This is the default
2389 framebuffer for sun4m machines and offers both 8-bit and 24-bit
2390 colour depths at a fixed resolution of 1024x768.
2392 ``cg3``
2393 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit
2394 framebuffer for sun4m machines available in both 1024x768
2395 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people
2396 wishing to run older Solaris versions.
2398 ``virtio``
2399 Virtio VGA card.
2401 ``none``
2402 Disable VGA card.
2403 ERST
2405 DEF("full-screen", 0, QEMU_OPTION_full_screen,
2406 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
2407 SRST
2408 ``-full-screen``
2409 Start in full screen.
2410 ERST
2412 DEF("g", HAS_ARG, QEMU_OPTION_g ,
2413 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
2414 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
2415 SRST
2416 ``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]``
2417 Set the initial graphical resolution and depth (PPC, SPARC only).
2419 For PPC the default is 800x600x32.
2421 For SPARC with the TCX graphics device, the default is 1024x768x8
2422 with the option of 1024x768x24. For cgthree, the default is
2423 1024x768x8 with the option of 1152x900x8 for people who wish to use
2424 OBP.
2425 ERST
2427 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
2428 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
2429 SRST
2430 ``-vnc display[,option[,option[,...]]]``
2431 Normally, if QEMU is compiled with graphical window support, it
2432 displays output such as guest graphics, guest console, and the QEMU
2433 monitor in a window. With this option, you can have QEMU listen on
2434 VNC display display and redirect the VGA display over the VNC
2435 session. It is very useful to enable the usb tablet device when
2436 using this option (option ``-device usb-tablet``). When using the
2437 VNC display, you must use the ``-k`` parameter to set the keyboard
2438 layout if you are not using en-us. Valid syntax for the display is
2440 ``to=L``
2441 With this option, QEMU will try next available VNC displays,
2442 until the number L, if the origianlly defined "-vnc display" is
2443 not available, e.g. port 5900+display is already used by another
2444 application. By default, to=0.
2446 ``host:d``
2447 TCP connections will only be allowed from host on display d. By
2448 convention the TCP port is 5900+d. Optionally, host can be
2449 omitted in which case the server will accept connections from
2450 any host.
2452 ``unix:path``
2453 Connections will be allowed over UNIX domain sockets where path
2454 is the location of a unix socket to listen for connections on.
2456 ``none``
2457 VNC is initialized but not started. The monitor ``change``
2458 command can be used to later start the VNC server.
2460 Following the display value there may be one or more option flags
2461 separated by commas. Valid options are
2463 ``reverse=on|off``
2464 Connect to a listening VNC client via a "reverse" connection.
2465 The client is specified by the display. For reverse network
2466 connections (host:d,``reverse``), the d argument is a TCP port
2467 number, not a display number.
2469 ``websocket=on|off``
2470 Opens an additional TCP listening port dedicated to VNC
2471 Websocket connections. If a bare websocket option is given, the
2472 Websocket port is 5700+display. An alternative port can be
2473 specified with the syntax ``websocket``\ =port.
2475 If host is specified connections will only be allowed from this
2476 host. It is possible to control the websocket listen address
2477 independently, using the syntax ``websocket``\ =host:port.
2479 If no TLS credentials are provided, the websocket connection
2480 runs in unencrypted mode. If TLS credentials are provided, the
2481 websocket connection requires encrypted client connections.
2483 ``password=on|off``
2484 Require that password based authentication is used for client
2485 connections.
2487 The password must be set separately using the ``set_password``
2488 command in the :ref:`QEMU monitor`. The
2489 syntax to change your password is:
2490 ``set_password <protocol> <password>`` where <protocol> could be
2491 either "vnc" or "spice".
2493 If you would like to change <protocol> password expiration, you
2494 should use ``expire_password <protocol> <expiration-time>``
2495 where expiration time could be one of the following options:
2496 now, never, +seconds or UNIX time of expiration, e.g. +60 to
2497 make password expire in 60 seconds, or 1335196800 to make
2498 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for
2499 this date and time).
2501 You can also use keywords "now" or "never" for the expiration
2502 time to allow <protocol> password to expire immediately or never
2503 expire.
2505 ``password-secret=<secret-id>``
2506 Require that password based authentication is used for client
2507 connections, using the password provided by the ``secret``
2508 object identified by ``secret-id``.
2510 ``tls-creds=ID``
2511 Provides the ID of a set of TLS credentials to use to secure the
2512 VNC server. They will apply to both the normal VNC server socket
2513 and the websocket socket (if enabled). Setting TLS credentials
2514 will cause the VNC server socket to enable the VeNCrypt auth
2515 mechanism. The credentials should have been previously created
2516 using the ``-object tls-creds`` argument.
2518 ``tls-authz=ID``
2519 Provides the ID of the QAuthZ authorization object against which
2520 the client's x509 distinguished name will validated. This object
2521 is only resolved at time of use, so can be deleted and recreated
2522 on the fly while the VNC server is active. If missing, it will
2523 default to denying access.
2525 ``sasl=on|off``
2526 Require that the client use SASL to authenticate with the VNC
2527 server. The exact choice of authentication method used is
2528 controlled from the system / user's SASL configuration file for
2529 the 'qemu' service. This is typically found in
2530 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user,
2531 an environment variable SASL\_CONF\_PATH can be used to make it
2532 search alternate locations for the service config. While some
2533 SASL auth methods can also provide data encryption (eg GSSAPI),
2534 it is recommended that SASL always be combined with the 'tls'
2535 and 'x509' settings to enable use of SSL and server
2536 certificates. This ensures a data encryption preventing
2537 compromise of authentication credentials. See the
2538 :ref:`VNC security` section in the System Emulation Users Guide
2539 for details on using SASL authentication.
2541 ``sasl-authz=ID``
2542 Provides the ID of the QAuthZ authorization object against which
2543 the client's SASL username will validated. This object is only
2544 resolved at time of use, so can be deleted and recreated on the
2545 fly while the VNC server is active. If missing, it will default
2546 to denying access.
2548 ``acl=on|off``
2549 Legacy method for enabling authorization of clients against the
2550 x509 distinguished name and SASL username. It results in the
2551 creation of two ``authz-list`` objects with IDs of
2552 ``vnc.username`` and ``vnc.x509dname``. The rules for these
2553 objects must be configured with the HMP ACL commands.
2555 This option is deprecated and should no longer be used. The new
2556 ``sasl-authz`` and ``tls-authz`` options are a replacement.
2558 ``lossy=on|off``
2559 Enable lossy compression methods (gradient, JPEG, ...). If this
2560 option is set, VNC client may receive lossy framebuffer updates
2561 depending on its encoding settings. Enabling this option can
2562 save a lot of bandwidth at the expense of quality.
2564 ``non-adaptive=on|off``
2565 Disable adaptive encodings. Adaptive encodings are enabled by
2566 default. An adaptive encoding will try to detect frequently
2567 updated screen regions, and send updates in these regions using
2568 a lossy encoding (like JPEG). This can be really helpful to save
2569 bandwidth when playing videos. Disabling adaptive encodings
2570 restores the original static behavior of encodings like Tight.
2572 ``share=[allow-exclusive|force-shared|ignore]``
2573 Set display sharing policy. 'allow-exclusive' allows clients to
2574 ask for exclusive access. As suggested by the rfb spec this is
2575 implemented by dropping other connections. Connecting multiple
2576 clients in parallel requires all clients asking for a shared
2577 session (vncviewer: -shared switch). This is the default.
2578 'force-shared' disables exclusive client access. Useful for
2579 shared desktop sessions, where you don't want someone forgetting
2580 specify -shared disconnect everybody else. 'ignore' completely
2581 ignores the shared flag and allows everybody connect
2582 unconditionally. Doesn't conform to the rfb spec but is
2583 traditional QEMU behavior.
2585 ``key-delay-ms``
2586 Set keyboard delay, for key down and key up events, in
2587 milliseconds. Default is 10. Keyboards are low-bandwidth
2588 devices, so this slowdown can help the device and guest to keep
2589 up and not lose events in case events are arriving in bulk.
2590 Possible causes for the latter are flaky network connections, or
2591 scripts for automated testing.
2593 ``audiodev=audiodev``
2594 Use the specified audiodev when the VNC client requests audio
2595 transmission. When not using an -audiodev argument, this option
2596 must be omitted, otherwise is must be present and specify a
2597 valid audiodev.
2599 ``power-control=on|off``
2600 Permit the remote client to issue shutdown, reboot or reset power
2601 control requests.
2602 ERST
2604 ARCHHEADING(, QEMU_ARCH_I386)
2606 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2608 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2609 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2610 QEMU_ARCH_I386)
2611 SRST
2612 ``-win2k-hack``
2613 Use it when installing Windows 2000 to avoid a disk full bug. After
2614 Windows 2000 is installed, you no longer need this option (this
2615 option slows down the IDE transfers).
2616 ERST
2618 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2619 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2620 QEMU_ARCH_I386)
2621 SRST
2622 ``-no-fd-bootchk``
2623 Disable boot signature checking for floppy disks in BIOS. May be
2624 needed to boot from old floppy disks.
2625 ERST
2627 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2628 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2629 SRST
2630 ``-no-acpi``
2631 Disable ACPI (Advanced Configuration and Power Interface) support.
2632 Use it if your guest OS complains about ACPI problems (PC target
2633 machine only).
2634 ERST
2636 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2637 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2638 SRST
2639 ``-no-hpet``
2640 Disable HPET support. Deprecated, use '-machine hpet=off' instead.
2641 ERST
2643 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2644 "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]\n"
2645 " ACPI table description\n", QEMU_ARCH_I386)
2646 SRST
2647 ``-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n] [,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]``
2648 Add ACPI table with specified header fields and context from
2649 specified files. For file=, take whole ACPI table from the specified
2650 files, including all ACPI headers (possible overridden by other
2651 options). For data=, only data portion of the table is used, all
2652 header information is specified in the command line. If a SLIC table
2653 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id
2654 fields will override the same in the RSDT and the FADT (a.k.a.
2655 FACP), in order to ensure the field matches required by the
2656 Microsoft SLIC spec and the ACPI spec.
2657 ERST
2659 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2660 "-smbios file=binary\n"
2661 " load SMBIOS entry from binary file\n"
2662 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2663 " [,uefi=on|off]\n"
2664 " specify SMBIOS type 0 fields\n"
2665 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2666 " [,uuid=uuid][,sku=str][,family=str]\n"
2667 " specify SMBIOS type 1 fields\n"
2668 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2669 " [,asset=str][,location=str]\n"
2670 " specify SMBIOS type 2 fields\n"
2671 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2672 " [,sku=str]\n"
2673 " specify SMBIOS type 3 fields\n"
2674 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2675 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
2676 " [,processor-id=%d]\n"
2677 " specify SMBIOS type 4 fields\n"
2678 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n"
2679 " specify SMBIOS type 8 fields\n"
2680 "-smbios type=11[,value=str][,path=filename]\n"
2681 " specify SMBIOS type 11 fields\n"
2682 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2683 " [,asset=str][,part=str][,speed=%d]\n"
2684 " specify SMBIOS type 17 fields\n"
2685 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n"
2686 " specify SMBIOS type 41 fields\n",
2687 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH)
2688 SRST
2689 ``-smbios file=binary``
2690 Load SMBIOS entry from binary file.
2692 ``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]``
2693 Specify SMBIOS type 0 fields
2695 ``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]``
2696 Specify SMBIOS type 1 fields
2698 ``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]``
2699 Specify SMBIOS type 2 fields
2701 ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
2702 Specify SMBIOS type 3 fields
2704 ``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]``
2705 Specify SMBIOS type 4 fields
2707 ``-smbios type=11[,value=str][,path=filename]``
2708 Specify SMBIOS type 11 fields
2710 This argument can be repeated multiple times, and values are added in the order they are parsed.
2711 Applications intending to use OEM strings data are encouraged to use their application name as
2712 a prefix for the value string. This facilitates passing information for multiple applications
2713 concurrently.
2715 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax
2716 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes.
2718 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to
2719 the SMBIOS table in the order in which they appear.
2721 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535
2722 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the
2723 guest. Instead it should be used as a indicator to inform the guest where to locate the real
2724 data set, for example, by specifying the serial ID of a block device.
2726 An example passing three strings is
2728 .. parsed-literal::
2730 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\
2731 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\
2732 path=/some/file/with/oemstringsdata.txt
2734 In the guest OS this is visible with the ``dmidecode`` command
2736 .. parsed-literal::
2738 $ dmidecode -t 11
2739 Handle 0x0E00, DMI type 11, 5 bytes
2740 OEM Strings
2741 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/
2742 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os
2743 String 3: myapp:some extra data
2746 ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
2747 Specify SMBIOS type 17 fields
2749 ``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]``
2750 Specify SMBIOS type 41 fields
2752 This argument can be repeated multiple times. Its main use is to allow network interfaces be created
2753 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface
2754 position on the PCI bus.
2756 Here is an example of use:
2758 .. parsed-literal::
2760 -netdev user,id=internet \\
2761 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\
2762 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev
2764 In the guest OS, the device should then appear as ``eno1``:
2766 ..parsed-literal::
2768 $ ip -brief l
2769 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
2770 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP>
2772 Currently, the PCI device has to be attached to the root bus.
2774 ERST
2776 DEFHEADING()
2778 DEFHEADING(Network options:)
2780 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2781 #ifdef CONFIG_SLIRP
2782 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n"
2783 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2784 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2785 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2786 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2787 #ifndef _WIN32
2788 "[,smb=dir[,smbserver=addr]]\n"
2789 #endif
2790 " configure a user mode network backend with ID 'str',\n"
2791 " its DHCP server and optional services\n"
2792 #endif
2793 #ifdef _WIN32
2794 "-netdev tap,id=str,ifname=name\n"
2795 " configure a host TAP network backend with ID 'str'\n"
2796 #else
2797 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2798 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2799 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2800 " [,poll-us=n]\n"
2801 " configure a host TAP network backend with ID 'str'\n"
2802 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2803 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2804 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2805 " to deconfigure it\n"
2806 " use '[down]script=no' to disable script execution\n"
2807 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2808 " configure it\n"
2809 " use 'fd=h' to connect to an already opened TAP interface\n"
2810 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2811 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2812 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2813 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2814 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2815 " use vhost=on to enable experimental in kernel accelerator\n"
2816 " (only has effect for virtio guests which use MSIX)\n"
2817 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2818 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2819 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2820 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2821 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n"
2822 " spent on busy polling for vhost net\n"
2823 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2824 " configure a host TAP network backend with ID 'str' that is\n"
2825 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2826 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2827 #endif
2828 #ifdef __linux__
2829 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2830 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n"
2831 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n"
2832 " [,rxcookie=rxcookie][,offset=offset]\n"
2833 " configure a network backend with ID 'str' connected to\n"
2834 " an Ethernet over L2TPv3 pseudowire.\n"
2835 " Linux kernel 3.3+ as well as most routers can talk\n"
2836 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2837 " VM to a router and even VM to Host. It is a nearly-universal\n"
2838 " standard (RFC3931). Note - this implementation uses static\n"
2839 " pre-configured tunnels (same as the Linux kernel).\n"
2840 " use 'src=' to specify source address\n"
2841 " use 'dst=' to specify destination address\n"
2842 " use 'udp=on' to specify udp encapsulation\n"
2843 " use 'srcport=' to specify source udp port\n"
2844 " use 'dstport=' to specify destination udp port\n"
2845 " use 'ipv6=on' to force v6\n"
2846 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2847 " well as a weak security measure\n"
2848 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2849 " use 'txcookie=0x012345678' to specify a txcookie\n"
2850 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2851 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2852 " use 'pincounter=on' to work around broken counter handling in peer\n"
2853 " use 'offset=X' to add an extra offset between header and data\n"
2854 #endif
2855 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2856 " configure a network backend to connect to another network\n"
2857 " using a socket connection\n"
2858 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2859 " configure a network backend to connect to a multicast maddr and port\n"
2860 " use 'localaddr=addr' to specify the host address to send packets from\n"
2861 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2862 " configure a network backend to connect to another network\n"
2863 " using an UDP tunnel\n"
2864 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n"
2865 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n"
2866 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n"
2867 " configure a network backend to connect to another network\n"
2868 " using a socket connection in stream mode.\n"
2869 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n"
2870 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n"
2871 " configure a network backend to connect to a multicast maddr and port\n"
2872 " use ``local.host=addr`` to specify the host address to send packets from\n"
2873 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n"
2874 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n"
2875 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n"
2876 " configure a network backend to connect to another network\n"
2877 " using an UDP tunnel\n"
2878 #ifdef CONFIG_VDE
2879 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2880 " configure a network backend to connect to port 'n' of a vde switch\n"
2881 " running on host and listening for incoming connections on 'socketpath'.\n"
2882 " Use group 'groupname' and mode 'octalmode' to change default\n"
2883 " ownership and permissions for communication port.\n"
2884 #endif
2885 #ifdef CONFIG_NETMAP
2886 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2887 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2888 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2889 " netmap device, defaults to '/dev/netmap')\n"
2890 #endif
2891 #ifdef CONFIG_AF_XDP
2892 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n"
2893 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n"
2894 " attach to the existing network interface 'name' with AF_XDP socket\n"
2895 " use 'mode=MODE' to specify an XDP program attach mode\n"
2896 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n"
2897 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n"
2898 " with inhibit=on,\n"
2899 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n"
2900 " added to a socket map in XDP program. One socket per queue.\n"
2901 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n"
2902 " use 'start-queue=m' to specify the first queue that should be used\n"
2903 #endif
2904 #ifdef CONFIG_POSIX
2905 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2906 " configure a vhost-user network, backed by a chardev 'dev'\n"
2907 #endif
2908 #ifdef __linux__
2909 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n"
2910 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n"
2911 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n"
2912 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n"
2913 #endif
2914 #ifdef CONFIG_VMNET
2915 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n"
2916 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n"
2917 " configure a vmnet network backend in host mode with ID 'str',\n"
2918 " isolate this interface from others with 'isolated',\n"
2919 " configure the address range and choose a subnet mask,\n"
2920 " specify network UUID 'uuid' to disable DHCP and interact with\n"
2921 " vmnet-host interfaces within this isolated network\n"
2922 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n"
2923 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n"
2924 " configure a vmnet network backend in shared mode with ID 'str',\n"
2925 " configure the address range and choose a subnet mask,\n"
2926 " set IPv6 ULA prefix (of length 64) to use for internal network,\n"
2927 " isolate this interface from others with 'isolated'\n"
2928 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n"
2929 " configure a vmnet network backend in bridged mode with ID 'str',\n"
2930 " use 'ifname=name' to select a physical network interface to be bridged,\n"
2931 " isolate this interface from others with 'isolated'\n"
2932 #endif
2933 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2934 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2935 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2936 "-nic [tap|bridge|"
2937 #ifdef CONFIG_SLIRP
2938 "user|"
2939 #endif
2940 #ifdef __linux__
2941 "l2tpv3|"
2942 #endif
2943 #ifdef CONFIG_VDE
2944 "vde|"
2945 #endif
2946 #ifdef CONFIG_NETMAP
2947 "netmap|"
2948 #endif
2949 #ifdef CONFIG_AF_XDP
2950 "af-xdp|"
2951 #endif
2952 #ifdef CONFIG_POSIX
2953 "vhost-user|"
2954 #endif
2955 #ifdef CONFIG_VMNET
2956 "vmnet-host|vmnet-shared|vmnet-bridged|"
2957 #endif
2958 "socket][,option][,...][mac=macaddr]\n"
2959 " initialize an on-board / default host NIC (using MAC address\n"
2960 " macaddr) and connect it to the given host network backend\n"
2961 "-nic none use it alone to have zero network devices (the default is to\n"
2962 " provided a 'user' network connection)\n",
2963 QEMU_ARCH_ALL)
2964 DEF("net", HAS_ARG, QEMU_OPTION_net,
2965 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2966 " configure or create an on-board (or machine default) NIC and\n"
2967 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2968 "-net ["
2969 #ifdef CONFIG_SLIRP
2970 "user|"
2971 #endif
2972 "tap|"
2973 "bridge|"
2974 #ifdef CONFIG_VDE
2975 "vde|"
2976 #endif
2977 #ifdef CONFIG_NETMAP
2978 "netmap|"
2979 #endif
2980 #ifdef CONFIG_AF_XDP
2981 "af-xdp|"
2982 #endif
2983 #ifdef CONFIG_VMNET
2984 "vmnet-host|vmnet-shared|vmnet-bridged|"
2985 #endif
2986 "socket][,option][,option][,...]\n"
2987 " old way to initialize a host network interface\n"
2988 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2989 SRST
2990 ``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
2991 This option is a shortcut for configuring both the on-board
2992 (default) guest NIC hardware and the host network backend in one go.
2993 The host backend options are the same as with the corresponding
2994 ``-netdev`` options below. The guest NIC model can be set with
2995 ``model=modelname``. Use ``model=help`` to list the available device
2996 types. The hardware MAC address can be set with ``mac=macaddr``.
2998 The following two example do exactly the same, to show how ``-nic``
2999 can be used to shorten the command line length:
3001 .. parsed-literal::
3003 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
3004 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
3006 ``-nic none``
3007 Indicate that no network devices should be configured. It is used to
3008 override the default configuration (default NIC with "user" host
3009 network backend) which is activated if no other networking options
3010 are provided.
3012 ``-netdev user,id=id[,option][,option][,...]``
3013 Configure user mode host network backend which requires no
3014 administrator privilege to run. Valid options are:
3016 ``id=id``
3017 Assign symbolic name for use in monitor commands.
3019 ``ipv4=on|off and ipv6=on|off``
3020 Specify that either IPv4 or IPv6 must be enabled. If neither is
3021 specified both protocols are enabled.
3023 ``net=addr[/mask]``
3024 Set IP network address the guest will see. Optionally specify
3025 the netmask, either in the form a.b.c.d or as number of valid
3026 top-most bits. Default is 10.0.2.0/24.
3028 ``host=addr``
3029 Specify the guest-visible address of the host. Default is the
3030 2nd IP in the guest network, i.e. x.x.x.2.
3032 ``ipv6-net=addr[/int]``
3033 Set IPv6 network address the guest will see (default is
3034 fec0::/64). The network prefix is given in the usual hexadecimal
3035 IPv6 address notation. The prefix size is optional, and is given
3036 as the number of valid top-most bits (default is 64).
3038 ``ipv6-host=addr``
3039 Specify the guest-visible IPv6 address of the host. Default is
3040 the 2nd IPv6 in the guest network, i.e. xxxx::2.
3042 ``restrict=on|off``
3043 If this option is enabled, the guest will be isolated, i.e. it
3044 will not be able to contact the host and no guest IP packets
3045 will be routed over the host to the outside. This option does
3046 not affect any explicitly set forwarding rules.
3048 ``hostname=name``
3049 Specifies the client hostname reported by the built-in DHCP
3050 server.
3052 ``dhcpstart=addr``
3053 Specify the first of the 16 IPs the built-in DHCP server can
3054 assign. Default is the 15th to 31st IP in the guest network,
3055 i.e. x.x.x.15 to x.x.x.31.
3057 ``dns=addr``
3058 Specify the guest-visible address of the virtual nameserver. The
3059 address must be different from the host address. Default is the
3060 3rd IP in the guest network, i.e. x.x.x.3.
3062 ``ipv6-dns=addr``
3063 Specify the guest-visible address of the IPv6 virtual
3064 nameserver. The address must be different from the host address.
3065 Default is the 3rd IP in the guest network, i.e. xxxx::3.
3067 ``dnssearch=domain``
3068 Provides an entry for the domain-search list sent by the
3069 built-in DHCP server. More than one domain suffix can be
3070 transmitted by specifying this option multiple times. If
3071 supported, this will cause the guest to automatically try to
3072 append the given domain suffix(es) in case a domain name can not
3073 be resolved.
3075 Example:
3077 .. parsed-literal::
3079 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
3081 ``domainname=domain``
3082 Specifies the client domain name reported by the built-in DHCP
3083 server.
3085 ``tftp=dir``
3086 When using the user mode network stack, activate a built-in TFTP
3087 server. The files in dir will be exposed as the root of a TFTP
3088 server. The TFTP client on the guest must be configured in
3089 binary mode (use the command ``bin`` of the Unix TFTP client).
3091 ``tftp-server-name=name``
3092 In BOOTP reply, broadcast name as the "TFTP server name"
3093 (RFC2132 option 66). This can be used to advise the guest to
3094 load boot files or configurations from a different server than
3095 the host address.
3097 ``bootfile=file``
3098 When using the user mode network stack, broadcast file as the
3099 BOOTP filename. In conjunction with ``tftp``, this can be used
3100 to network boot a guest from a local directory.
3102 Example (using pxelinux):
3104 .. parsed-literal::
3106 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\
3107 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
3109 ``smb=dir[,smbserver=addr]``
3110 When using the user mode network stack, activate a built-in SMB
3111 server so that Windows OSes can access to the host files in
3112 ``dir`` transparently. The IP address of the SMB server can be
3113 set to addr. By default the 4th IP in the guest network is used,
3114 i.e. x.x.x.4.
3116 In the guest Windows OS, the line:
3120 10.0.2.4 smbserver
3122 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
3123 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
3124 NT/2000).
3126 Then ``dir`` can be accessed in ``\\smbserver\qemu``.
3128 Note that a SAMBA server must be installed on the host OS.
3130 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport``
3131 Redirect incoming TCP or UDP connections to the host port
3132 hostport to the guest IP address guestaddr on guest port
3133 guestport. If guestaddr is not specified, its value is x.x.x.15
3134 (default first address given by the built-in DHCP server). By
3135 specifying hostaddr, the rule can be bound to a specific host
3136 interface. If no connection type is set, TCP is used. This
3137 option can be given multiple times.
3139 For example, to redirect host X11 connection from screen 1 to
3140 guest screen 0, use the following:
3142 .. parsed-literal::
3144 # on the host
3145 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
3146 # this host xterm should open in the guest X11 server
3147 xterm -display :1
3149 To redirect telnet connections from host port 5555 to telnet
3150 port on the guest, use the following:
3152 .. parsed-literal::
3154 # on the host
3155 |qemu_system| -nic user,hostfwd=tcp::5555-:23
3156 telnet localhost 5555
3158 Then when you use on the host ``telnet localhost 5555``, you
3159 connect to the guest telnet server.
3161 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command``
3162 Forward guest TCP connections to the IP address server on port
3163 port to the character device dev or to a program executed by
3164 cmd:command which gets spawned for each connection. This option
3165 can be given multiple times.
3167 You can either use a chardev directly and have that one used
3168 throughout QEMU's lifetime, like in the following example:
3170 .. parsed-literal::
3172 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
3173 # the guest accesses it
3174 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
3176 Or you can execute a command on every TCP connection established
3177 by the guest, so that QEMU behaves similar to an inetd process
3178 for that virtual server:
3180 .. parsed-literal::
3182 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
3183 # and connect the TCP stream to its stdin/stdout
3184 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
3186 ``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]``
3187 Configure a host TAP network backend with ID id.
3189 Use the network script file to configure it and the network script
3190 dfile to deconfigure it. If name is not provided, the OS
3191 automatically provides one. The default network configure script is
3192 ``/etc/qemu-ifup`` and the default network deconfigure script is
3193 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to
3194 disable script execution.
3196 If running QEMU as an unprivileged user, use the network helper
3197 to configure the TAP interface and attach it to the bridge.
3198 The default network helper executable is
3199 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3200 ``br0``.
3202 ``fd``\ =h can be used to specify the handle of an already opened
3203 host TAP interface.
3205 Examples:
3207 .. parsed-literal::
3209 #launch a QEMU instance with the default network script
3210 |qemu_system| linux.img -nic tap
3212 .. parsed-literal::
3214 #launch a QEMU instance with two NICs, each one connected
3215 #to a TAP device
3216 |qemu_system| linux.img \\
3217 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\
3218 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
3220 .. parsed-literal::
3222 #launch a QEMU instance with the default network helper to
3223 #connect a TAP device to bridge br0
3224 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3225 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
3227 ``-netdev bridge,id=id[,br=bridge][,helper=helper]``
3228 Connect a host TAP network interface to a host bridge device.
3230 Use the network helper helper to configure the TAP interface and
3231 attach it to the bridge. The default network helper executable is
3232 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3233 ``br0``.
3235 Examples:
3237 .. parsed-literal::
3239 #launch a QEMU instance with the default network helper to
3240 #connect a TAP device to bridge br0
3241 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
3243 .. parsed-literal::
3245 #launch a QEMU instance with the default network helper to
3246 #connect a TAP device to bridge qemubr0
3247 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
3249 ``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]``
3250 This host network backend can be used to connect the guest's network
3251 to another QEMU virtual machine using a TCP socket connection. If
3252 ``listen`` is specified, QEMU waits for incoming connections on port
3253 (host is optional). ``connect`` is used to connect to another QEMU
3254 instance using the ``listen`` option. ``fd``\ =h specifies an
3255 already opened TCP socket.
3257 Example:
3259 .. parsed-literal::
3261 # launch a first QEMU instance
3262 |qemu_system| linux.img \\
3263 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3264 -netdev socket,id=n1,listen=:1234
3265 # connect the network of this instance to the network of the first instance
3266 |qemu_system| linux.img \\
3267 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3268 -netdev socket,id=n2,connect=127.0.0.1:1234
3270 ``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]``
3271 Configure a socket host network backend to share the guest's network
3272 traffic with another QEMU virtual machines using a UDP multicast
3273 socket, effectively making a bus for every QEMU with same multicast
3274 address maddr and port. NOTES:
3276 1. Several QEMU can be running on different hosts and share same bus
3277 (assuming correct multicast setup for these hosts).
3279 2. mcast support is compatible with User Mode Linux (argument
3280 ``ethN=mcast``), see http://user-mode-linux.sf.net.
3282 3. Use ``fd=h`` to specify an already opened UDP multicast socket.
3284 Example:
3286 .. parsed-literal::
3288 # launch one QEMU instance
3289 |qemu_system| linux.img \\
3290 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3291 -netdev socket,id=n1,mcast=230.0.0.1:1234
3292 # launch another QEMU instance on same "bus"
3293 |qemu_system| linux.img \\
3294 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3295 -netdev socket,id=n2,mcast=230.0.0.1:1234
3296 # launch yet another QEMU instance on same "bus"
3297 |qemu_system| linux.img \\
3298 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\
3299 -netdev socket,id=n3,mcast=230.0.0.1:1234
3301 Example (User Mode Linux compat.):
3303 .. parsed-literal::
3305 # launch QEMU instance (note mcast address selected is UML's default)
3306 |qemu_system| linux.img \\
3307 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3308 -netdev socket,id=n1,mcast=239.192.168.1:1102
3309 # launch UML
3310 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
3312 Example (send packets from host's 1.2.3.4):
3314 .. parsed-literal::
3316 |qemu_system| linux.img \\
3317 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3318 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
3320 ``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]``
3321 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
3322 is a popular protocol to transport Ethernet (and other Layer 2) data
3323 frames between two systems. It is present in routers, firewalls and
3324 the Linux kernel (from version 3.3 onwards).
3326 This transport allows a VM to communicate to another VM, router or
3327 firewall directly.
3329 ``src=srcaddr``
3330 source address (mandatory)
3332 ``dst=dstaddr``
3333 destination address (mandatory)
3335 ``udp``
3336 select udp encapsulation (default is ip).
3338 ``srcport=srcport``
3339 source udp port.
3341 ``dstport=dstport``
3342 destination udp port.
3344 ``ipv6``
3345 force v6, otherwise defaults to v4.
3347 ``rxcookie=rxcookie``; \ ``txcookie=txcookie``
3348 Cookies are a weak form of security in the l2tpv3 specification.
3349 Their function is mostly to prevent misconfiguration. By default
3350 they are 32 bit.
3352 ``cookie64``
3353 Set cookie size to 64 bit instead of the default 32
3355 ``counter=off``
3356 Force a 'cut-down' L2TPv3 with no counter as in
3357 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
3359 ``pincounter=on``
3360 Work around broken counter handling in peer. This may also help
3361 on networks which have packet reorder.
3363 ``offset=offset``
3364 Add an extra offset between header and data
3366 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to
3367 the bridge br-lan on the remote Linux host 1.2.3.4:
3369 .. parsed-literal::
3371 # Setup tunnel on linux host using raw ip as encapsulation
3372 # on 1.2.3.4
3373 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\
3374 encap udp udp_sport 16384 udp_dport 16384
3375 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\
3376 0xFFFFFFFF peer_session_id 0xFFFFFFFF
3377 ifconfig vmtunnel0 mtu 1500
3378 ifconfig vmtunnel0 up
3379 brctl addif br-lan vmtunnel0
3382 # on 4.3.2.1
3383 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
3385 |qemu_system| linux.img -device e1000,netdev=n1 \\
3386 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
3388 ``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]``
3389 Configure VDE backend to connect to PORT n of a vde switch running
3390 on host and listening for incoming connections on socketpath. Use
3391 GROUP groupname and MODE octalmode to change default ownership and
3392 permissions for communication port. This option is only available if
3393 QEMU has been compiled with vde support enabled.
3395 Example:
3397 .. parsed-literal::
3399 # launch vde switch
3400 vde_switch -F -sock /tmp/myswitch
3401 # launch QEMU instance
3402 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch
3404 ``-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off][,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]``
3405 Configure AF_XDP backend to connect to a network interface 'name'
3406 using AF_XDP socket. A specific program attach mode for a default
3407 XDP program can be forced with 'mode', defaults to best-effort,
3408 where the likely most performant mode will be in use. Number of queues
3409 'n' should generally match the number or queues in the interface,
3410 defaults to 1. Traffic arriving on non-configured device queues will
3411 not be delivered to the network backend.
3413 .. parsed-literal::
3415 # set number of queues to 4
3416 ethtool -L eth0 combined 4
3417 # launch QEMU instance
3418 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3419 -netdev af-xdp,id=n1,ifname=eth0,queues=4
3421 'start-queue' option can be specified if a particular range of queues
3422 [m, m + n] should be in use. For example, this is may be necessary in
3423 order to use certain NICs in native mode. Kernel allows the driver to
3424 create a separate set of XDP queues on top of regular ones, and only
3425 these queues can be used for AF_XDP sockets. NICs that work this way
3426 may also require an additional traffic redirection with ethtool to these
3427 special queues.
3429 .. parsed-literal::
3431 # set number of queues to 1
3432 ethtool -L eth0 combined 1
3433 # redirect all the traffic to the second queue (id: 1)
3434 # note: drivers may require non-empty key/mask pair.
3435 ethtool -N eth0 flow-type ether \\
3436 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1
3437 ethtool -N eth0 flow-type ether \\
3438 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1
3439 # launch QEMU instance
3440 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3441 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1
3443 XDP program can also be loaded externally. In this case 'inhibit' option
3444 should be set to 'on' and 'sock-fds' provided with file descriptors for
3445 already open but not bound XDP sockets already added to a socket map for
3446 corresponding queues. One socket per queue.
3448 .. parsed-literal::
3450 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3451 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17
3453 ``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
3454 Establish a vhost-user netdev, backed by a chardev id. The chardev
3455 should be a unix domain socket backed one. The vhost-user uses a
3456 specifically defined protocol to pass vhost ioctl replacement
3457 messages to an application on the other end of the socket. On
3458 non-MSIX guests, the feature can be forced with vhostforce. Use
3459 'queues=n' to specify the number of queues to be created for
3460 multiqueue vhost-user.
3462 Example:
3466 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
3467 -numa node,memdev=mem \
3468 -chardev socket,id=chr0,path=/path/to/socket \
3469 -netdev type=vhost-user,id=net0,chardev=chr0 \
3470 -device virtio-net-pci,netdev=net0
3472 ``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]``
3473 Establish a vhost-vdpa netdev.
3475 vDPA device is a device that uses a datapath which complies with
3476 the virtio specifications with a vendor specific control path.
3477 vDPA devices can be both physically located on the hardware or
3478 emulated by software.
3480 ``-netdev hubport,id=id,hubid=hubid[,netdev=nd]``
3481 Create a hub port on the emulated hub with ID hubid.
3483 The hubport netdev lets you connect a NIC to a QEMU emulated hub
3484 instead of a single netdev. Alternatively, you can also connect the
3485 hubport to another netdev with ID nd by using the ``netdev=nd``
3486 option.
3488 ``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]``
3489 Legacy option to configure or create an on-board (or machine
3490 default) Network Interface Card(NIC) and connect it either to the
3491 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd.
3492 If model is omitted, then the default NIC model associated with the
3493 machine type is used. Note that the default NIC model may change in
3494 future QEMU releases, so it is highly recommended to always specify
3495 a model. Optionally, the MAC address can be changed to mac, the
3496 device address set to addr (PCI cards only), and a name can be
3497 assigned for use in monitor commands. Optionally, for PCI cards, you
3498 can specify the number v of MSI-X vectors that the card should have;
3499 this option currently only affects virtio cards; set v = 0 to
3500 disable MSI-X. If no ``-net`` option is specified, a single NIC is
3501 created. QEMU can emulate several different models of network card.
3502 Use ``-net nic,model=help`` for a list of available devices for your
3503 target.
3505 ``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]``
3506 Configure a host network backend (with the options corresponding to
3507 the same ``-netdev`` option) and connect it to the emulated hub 0
3508 (the default hub). Use name to specify the name of the hub port.
3509 ERST
3511 DEFHEADING()
3513 DEFHEADING(Character device options:)
3515 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
3516 "-chardev help\n"
3517 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3518 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n"
3519 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
3520 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
3521 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
3522 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n"
3523 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
3524 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
3525 " [,logfile=PATH][,logappend=on|off]\n"
3526 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3527 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
3528 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3529 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
3530 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3531 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3532 #ifdef _WIN32
3533 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3534 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3535 #else
3536 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3537 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
3538 #endif
3539 #ifdef CONFIG_BRLAPI
3540 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3541 #endif
3542 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
3543 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
3544 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3545 #endif
3546 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
3547 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3548 #endif
3549 #if defined(CONFIG_SPICE)
3550 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3551 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3552 #endif
3553 , QEMU_ARCH_ALL
3556 SRST
3557 The general form of a character device option is:
3559 ``-chardev backend,id=id[,mux=on|off][,options]``
3560 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``,
3561 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``,
3562 ``pty``, ``stdio``, ``braille``, ``parallel``,
3563 ``spicevmc``, ``spiceport``. The specific backend will determine the
3564 applicable options.
3566 Use ``-chardev help`` to print all available chardev backend types.
3568 All devices must have an id, which can be any string up to 127
3569 characters long. It is used to uniquely identify this device in
3570 other command line directives.
3572 A character device may be used in multiplexing mode by multiple
3573 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is
3574 a "1:N" device, and here the "1" end is your specified chardev
3575 backend, and the "N" end is the various parts of QEMU that can talk
3576 to a chardev. If you create a chardev with ``id=myid`` and
3577 ``mux=on``, QEMU will create a multiplexer with your specified ID,
3578 and you can then configure multiple front ends to use that chardev
3579 ID for their input/output. Up to four different front ends can be
3580 connected to a single multiplexed chardev. (Without multiplexing
3581 enabled, a chardev can only be used by a single front end.) For
3582 instance you could use this to allow a single stdio chardev to be
3583 used by two serial ports and the QEMU monitor:
3587 -chardev stdio,mux=on,id=char0 \
3588 -mon chardev=char0,mode=readline \
3589 -serial chardev:char0 \
3590 -serial chardev:char0
3592 You can have more than one multiplexer in a system configuration;
3593 for instance you could have a TCP port multiplexed between UART 0
3594 and UART 1, and stdio multiplexed between the QEMU monitor and a
3595 parallel port:
3599 -chardev stdio,mux=on,id=char0 \
3600 -mon chardev=char0,mode=readline \
3601 -parallel chardev:char0 \
3602 -chardev tcp,...,mux=on,id=char1 \
3603 -serial chardev:char1 \
3604 -serial chardev:char1
3606 When you're using a multiplexed character device, some escape
3607 sequences are interpreted in the input. See the chapter about
3608 :ref:`keys in the character backend multiplexer` in the
3609 System Emulation Users Guide for more details.
3611 Note that some other command line options may implicitly create
3612 multiplexed character backends; for instance ``-serial mon:stdio``
3613 creates a multiplexed stdio backend connected to the serial port and
3614 the QEMU monitor, and ``-nographic`` also multiplexes the console
3615 and the monitor to stdio.
3617 There is currently no support for multiplexing in the other
3618 direction (where a single QEMU front end takes input and output from
3619 multiple chardevs).
3621 Every backend supports the ``logfile`` option, which supplies the
3622 path to a file to record all data transmitted via the backend. The
3623 ``logappend`` option controls whether the log file will be truncated
3624 or appended to when opened.
3626 The available backends are:
3628 ``-chardev null,id=id``
3629 A void device. This device will not emit any data, and will drop any
3630 data it receives. The null backend does not take any options.
3632 ``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]``
3633 Create a two-way stream socket, which can be either a TCP or a unix
3634 socket. A unix socket will be created if ``path`` is specified.
3635 Behaviour is undefined if TCP options are specified for a unix
3636 socket.
3638 ``server=on|off`` specifies that the socket shall be a listening socket.
3640 ``wait=on|off`` specifies that QEMU should not block waiting for a client
3641 to connect to a listening socket.
3643 ``telnet=on|off`` specifies that traffic on the socket should interpret
3644 telnet escape sequences.
3646 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for
3647 communication.
3649 ``reconnect`` sets the timeout for reconnecting on non-server
3650 sockets when the remote end goes away. qemu will delay this many
3651 seconds and then attempt to reconnect. Zero disables reconnecting,
3652 and is the default.
3654 ``tls-creds`` requests enablement of the TLS protocol for
3655 encryption, and specifies the id of the TLS credentials to use for
3656 the handshake. The credentials must be previously created with the
3657 ``-object tls-creds`` argument.
3659 ``tls-auth`` provides the ID of the QAuthZ authorization object
3660 against which the client's x509 distinguished name will be
3661 validated. This object is only resolved at time of use, so can be
3662 deleted and recreated on the fly while the chardev server is active.
3663 If missing, it will default to denying access.
3665 TCP and unix socket options are given below:
3667 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]``
3668 ``host`` for a listening socket specifies the local address to
3669 be bound. For a connecting socket species the remote host to
3670 connect to. ``host`` is optional for listening sockets. If not
3671 specified it defaults to ``0.0.0.0``.
3673 ``port`` for a listening socket specifies the local port to be
3674 bound. For a connecting socket specifies the port on the remote
3675 host to connect to. ``port`` can be given as either a port
3676 number or a service name. ``port`` is required.
3678 ``to`` is only relevant to listening sockets. If it is
3679 specified, and ``port`` cannot be bound, QEMU will attempt to
3680 bind to subsequent ports up to and including ``to`` until it
3681 succeeds. ``to`` must be specified as a port number.
3683 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4
3684 or IPv6 must be used. If neither is specified the socket may
3685 use either protocol.
3687 ``nodelay=on|off`` disables the Nagle algorithm.
3689 ``unix options: path=path[,abstract=on|off][,tight=on|off]``
3690 ``path`` specifies the local path of the unix socket. ``path``
3691 is required.
3692 ``abstract=on|off`` specifies the use of the abstract socket namespace,
3693 rather than the filesystem. Optional, defaults to false.
3694 ``tight=on|off`` sets the socket length of abstract sockets to their minimum,
3695 rather than the full sun_path length. Optional, defaults to true.
3697 ``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]``
3698 Sends all traffic from the guest to a remote host over UDP.
3700 ``host`` specifies the remote host to connect to. If not specified
3701 it defaults to ``localhost``.
3703 ``port`` specifies the port on the remote host to connect to.
3704 ``port`` is required.
3706 ``localaddr`` specifies the local address to bind to. If not
3707 specified it defaults to ``0.0.0.0``.
3709 ``localport`` specifies the local port to bind to. If not specified
3710 any available local port will be used.
3712 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used.
3713 If neither is specified the device may use either protocol.
3715 ``-chardev msmouse,id=id``
3716 Forward QEMU's emulated msmouse events to the guest. ``msmouse``
3717 does not take any options.
3719 ``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]``
3720 Connect to a QEMU text console. ``vc`` may optionally be given a
3721 specific size.
3723 ``width`` and ``height`` specify the width and height respectively
3724 of the console, in pixels.
3726 ``cols`` and ``rows`` specify that the console be sized to fit a
3727 text console with the given dimensions.
3729 ``-chardev ringbuf,id=id[,size=size]``
3730 Create a ring buffer with fixed size ``size``. size must be a power
3731 of two and defaults to ``64K``.
3733 ``-chardev file,id=id,path=path[,input-path=input-path]``
3734 Log all traffic received from the guest to a file.
3736 ``path`` specifies the path of the file to be opened. This file will
3737 be created if it does not already exist, and overwritten if it does.
3738 ``path`` is required.
3740 If ``input-path`` is specified, this is the path of a second file
3741 which will be used for input. If ``input-path`` is not specified,
3742 no input will be available from the chardev.
3744 Note that ``input-path`` is not supported on Windows hosts.
3746 ``-chardev pipe,id=id,path=path``
3747 Create a two-way connection to the guest. The behaviour differs
3748 slightly between Windows hosts and other hosts:
3750 On Windows, a single duplex pipe will be created at
3751 ``\\.pipe\path``.
3753 On other hosts, 2 pipes will be created called ``path.in`` and
3754 ``path.out``. Data written to ``path.in`` will be received by the
3755 guest. Data written by the guest can be read from ``path.out``. QEMU
3756 will not create these fifos, and requires them to be present.
3758 ``path`` forms part of the pipe path as described above. ``path`` is
3759 required.
3761 ``-chardev console,id=id``
3762 Send traffic from the guest to QEMU's standard output. ``console``
3763 does not take any options.
3765 ``console`` is only available on Windows hosts.
3767 ``-chardev serial,id=id,path=path``
3768 Send traffic from the guest to a serial device on the host.
3770 On Unix hosts serial will actually accept any tty device, not only
3771 serial lines.
3773 ``path`` specifies the name of the serial device to open.
3775 ``-chardev pty,id=id``
3776 Create a new pseudo-terminal on the host and connect to it. ``pty``
3777 does not take any options.
3779 ``pty`` is not available on Windows hosts.
3781 ``-chardev stdio,id=id[,signal=on|off]``
3782 Connect to standard input and standard output of the QEMU process.
3784 ``signal`` controls if signals are enabled on the terminal, that
3785 includes exiting QEMU with the key sequence Control-c. This option
3786 is enabled by default, use ``signal=off`` to disable it.
3788 ``-chardev braille,id=id``
3789 Connect to a local BrlAPI server. ``braille`` does not take any
3790 options.
3792 ``-chardev parallel,id=id,path=path``
3794 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD
3795 hosts.
3797 Connect to a local parallel port.
3799 ``path`` specifies the path to the parallel port device. ``path`` is
3800 required.
3802 ``-chardev spicevmc,id=id,debug=debug,name=name``
3803 ``spicevmc`` is only available when spice support is built in.
3805 ``debug`` debug level for spicevmc
3807 ``name`` name of spice channel to connect to
3809 Connect to a spice virtual machine channel, such as vdiport.
3811 ``-chardev spiceport,id=id,debug=debug,name=name``
3812 ``spiceport`` is only available when spice support is built in.
3814 ``debug`` debug level for spicevmc
3816 ``name`` name of spice port to connect to
3818 Connect to a spice port, allowing a Spice client to handle the
3819 traffic identified by a name (preferably a fqdn).
3820 ERST
3822 DEFHEADING()
3824 #ifdef CONFIG_TPM
3825 DEFHEADING(TPM device options:)
3827 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3828 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3829 " use path to provide path to a character device; default is /dev/tpm0\n"
3830 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3831 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3832 "-tpmdev emulator,id=id,chardev=dev\n"
3833 " configure the TPM device using chardev backend\n",
3834 QEMU_ARCH_ALL)
3835 SRST
3836 The general form of a TPM device option is:
3838 ``-tpmdev backend,id=id[,options]``
3839 The specific backend type will determine the applicable options. The
3840 ``-tpmdev`` option creates the TPM backend and requires a
3841 ``-device`` option that specifies the TPM frontend interface model.
3843 Use ``-tpmdev help`` to print all available TPM backend types.
3845 The available backends are:
3847 ``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path``
3848 (Linux-host only) Enable access to the host's TPM using the
3849 passthrough driver.
3851 ``path`` specifies the path to the host's TPM device, i.e., on a
3852 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by
3853 default ``/dev/tpm0`` is used.
3855 ``cancel-path`` specifies the path to the host TPM device's sysfs
3856 entry allowing for cancellation of an ongoing TPM command.
3857 ``cancel-path`` is optional and by default QEMU will search for the
3858 sysfs entry to use.
3860 Some notes about using the host's TPM with the passthrough driver:
3862 The TPM device accessed by the passthrough driver must not be used
3863 by any other application on the host.
3865 Since the host's firmware (BIOS/UEFI) has already initialized the
3866 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize
3867 the TPM again and may therefore not show a TPM-specific menu that
3868 would otherwise allow the user to configure the TPM, e.g., allow the
3869 user to enable/disable or activate/deactivate the TPM. Further, if
3870 TPM ownership is released from within a VM then the host's TPM will
3871 get disabled and deactivated. To enable and activate the TPM again
3872 afterwards, the host has to be rebooted and the user is required to
3873 enter the firmware's menu to enable and activate the TPM. If the TPM
3874 is left disabled and/or deactivated most TPM commands will fail.
3876 To create a passthrough TPM use the following two options:
3880 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3882 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by
3883 ``tpmdev=tpm0`` in the device option.
3885 ``-tpmdev emulator,id=id,chardev=dev``
3886 (Linux-host only) Enable access to a TPM emulator using Unix domain
3887 socket based chardev backend.
3889 ``chardev`` specifies the unique ID of a character device backend
3890 that provides connection to the software TPM server.
3892 To create a TPM emulator backend device with chardev socket backend:
3896 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3897 ERST
3899 DEFHEADING()
3901 #endif
3903 DEFHEADING(Boot Image or Kernel specific:)
3904 SRST
3905 There are broadly 4 ways you can boot a system with QEMU.
3907 - specify a firmware and let it control finding a kernel
3908 - specify a firmware and pass a hint to the kernel to boot
3909 - direct kernel image boot
3910 - manually load files into the guest's address space
3912 The third method is useful for quickly testing kernels but as there is
3913 no firmware to pass configuration information to the kernel the
3914 hardware must either be probeable, the kernel built for the exact
3915 configuration or passed some configuration data (e.g. a DTB blob)
3916 which tells the kernel what drivers it needs. This exact details are
3917 often hardware specific.
3919 The final method is the most generic way of loading images into the
3920 guest address space and used mostly for ``bare metal`` type
3921 development where the reset vectors of the processor are taken into
3922 account.
3924 ERST
3926 SRST
3928 For x86 machines and some other architectures ``-bios`` will generally
3929 do the right thing with whatever it is given. For other machines the
3930 more strict ``-pflash`` option needs an image that is sized for the
3931 flash device for the given machine type.
3933 Please see the :ref:`system-targets-ref` section of the manual for
3934 more detailed documentation.
3936 ERST
3938 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3939 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3940 SRST
3941 ``-bios file``
3942 Set the filename for the BIOS.
3943 ERST
3945 DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
3946 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
3947 SRST
3948 ``-pflash file``
3949 Use file as a parallel flash image.
3950 ERST
3952 SRST
3954 The kernel options were designed to work with Linux kernels although
3955 other things (like hypervisors) can be packaged up as a kernel
3956 executable image. The exact format of a executable image is usually
3957 architecture specific.
3959 The way in which the kernel is started (what address it is loaded at,
3960 what if any information is passed to it via CPU registers, the state
3961 of the hardware when it is started, and so on) is also architecture
3962 specific. Typically it follows the specification laid down by the
3963 Linux kernel for how kernels for that architecture must be started.
3965 ERST
3967 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3968 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3969 SRST
3970 ``-kernel bzImage``
3971 Use bzImage as kernel image. The kernel can be either a Linux kernel
3972 or in multiboot format.
3973 ERST
3975 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3976 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3977 SRST
3978 ``-append cmdline``
3979 Use cmdline as kernel command line
3980 ERST
3982 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3983 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3984 SRST
3985 ``-initrd file``
3986 Use file as initial ram disk.
3988 ``-initrd "file1 arg=foo,file2"``
3989 This syntax is only available with multiboot.
3991 Use file1 and file2 as modules and pass arg=foo as parameter to the
3992 first module.
3993 ERST
3995 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3996 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3997 SRST
3998 ``-dtb file``
3999 Use file as a device tree binary (dtb) image and pass it to the
4000 kernel on boot.
4001 ERST
4003 SRST
4005 Finally you can also manually load images directly into the address
4006 space of the guest. This is most useful for developers who already
4007 know the layout of their guest and take care to ensure something sane
4008 will happen when the reset vector executes.
4010 The generic loader can be invoked by using the loader device:
4012 ``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]``
4014 there is also the guest loader which operates in a similar way but
4015 tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where
4016 the guest image is:
4018 ``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]``
4020 ERST
4022 DEFHEADING()
4024 DEFHEADING(Debug/Expert options:)
4026 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
4027 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
4028 " Policy for handling deprecated management interfaces\n"
4029 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n"
4030 " Policy for handling unstable management interfaces\n",
4031 QEMU_ARCH_ALL)
4032 SRST
4033 ``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]``
4034 Set policy for handling deprecated management interfaces (experimental):
4036 ``deprecated-input=accept`` (default)
4037 Accept deprecated commands and arguments
4038 ``deprecated-input=reject``
4039 Reject deprecated commands and arguments
4040 ``deprecated-input=crash``
4041 Crash on deprecated commands and arguments
4042 ``deprecated-output=accept`` (default)
4043 Emit deprecated command results and events
4044 ``deprecated-output=hide``
4045 Suppress deprecated command results and events
4047 Limitation: covers only syntactic aspects of QMP.
4049 ``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]``
4050 Set policy for handling unstable management interfaces (experimental):
4052 ``unstable-input=accept`` (default)
4053 Accept unstable commands and arguments
4054 ``unstable-input=reject``
4055 Reject unstable commands and arguments
4056 ``unstable-input=crash``
4057 Crash on unstable commands and arguments
4058 ``unstable-output=accept`` (default)
4059 Emit unstable command results and events
4060 ``unstable-output=hide``
4061 Suppress unstable command results and events
4063 Limitation: covers only syntactic aspects of QMP.
4064 ERST
4066 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
4067 "-fw_cfg [name=]<name>,file=<file>\n"
4068 " add named fw_cfg entry with contents from file\n"
4069 "-fw_cfg [name=]<name>,string=<str>\n"
4070 " add named fw_cfg entry with contents from string\n",
4071 QEMU_ARCH_ALL)
4072 SRST
4073 ``-fw_cfg [name=]name,file=file``
4074 Add named fw\_cfg entry with contents from file file.
4076 ``-fw_cfg [name=]name,string=str``
4077 Add named fw\_cfg entry with contents from string str.
4079 The terminating NUL character of the contents of str will not be
4080 included as part of the fw\_cfg item data. To insert contents with
4081 embedded NUL characters, you have to use the file parameter.
4083 The fw\_cfg entries are passed by QEMU through to the guest.
4085 Example:
4089 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
4091 creates an fw\_cfg entry named opt/com.mycompany/blob with contents
4092 from ./my\_blob.bin.
4093 ERST
4095 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
4096 "-serial dev redirect the serial port to char device 'dev'\n",
4097 QEMU_ARCH_ALL)
4098 SRST
4099 ``-serial dev``
4100 Redirect the virtual serial port to host character device dev. The
4101 default device is ``vc`` in graphical mode and ``stdio`` in non
4102 graphical mode.
4104 This option can be used several times to simulate up to 4 serial
4105 ports.
4107 Use ``-serial none`` to disable all serial ports.
4109 Available character devices are:
4111 ``vc[:WxH]``
4112 Virtual console. Optionally, a width and height can be given in
4113 pixel with
4117 vc:800x600
4119 It is also possible to specify width or height in characters:
4123 vc:80Cx24C
4125 ``pty``
4126 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
4128 ``none``
4129 No device is allocated.
4131 ``null``
4132 void device
4134 ``chardev:id``
4135 Use a named character device defined with the ``-chardev``
4136 option.
4138 ``/dev/XXX``
4139 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial
4140 port parameters are set according to the emulated ones.
4142 ``/dev/parportN``
4143 [Linux only, parallel port only] Use host parallel port N.
4144 Currently SPP and EPP parallel port features can be used.
4146 ``file:filename``
4147 Write output to filename. No character can be read.
4149 ``stdio``
4150 [Unix only] standard input/output
4152 ``pipe:filename``
4153 name pipe filename
4155 ``COMn``
4156 [Windows only] Use host serial port n
4158 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]``
4159 This implements UDP Net Console. When remote\_host or src\_ip
4160 are not specified they default to ``0.0.0.0``. When not using a
4161 specified src\_port a random port is automatically chosen.
4163 If you just want a simple readonly console you can use
4164 ``netcat`` or ``nc``, by starting QEMU with:
4165 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time
4166 QEMU writes something to that port it will appear in the
4167 netconsole session.
4169 If you plan to send characters back via netconsole or you want
4170 to stop and start QEMU a lot of times, you should have QEMU use
4171 the same source port each time by using something like ``-serial
4172 udp::4555@:4556`` to QEMU. Another approach is to use a patched
4173 version of netcat which can listen to a TCP port and send and
4174 receive characters via udp. If you have a patched version of
4175 netcat which activates telnet remote echo and single char
4176 transfer, then you can use the following options to set up a
4177 netcat redirector to allow telnet on port 5555 to access the
4178 QEMU port.
4180 ``QEMU Options:``
4181 -serial udp::4555@:4556
4183 ``netcat options:``
4184 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
4186 ``telnet options:``
4187 localhost 5555
4189 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]``
4190 The TCP Net Console has two modes of operation. It can send the
4191 serial I/O to a location or wait for a connection from a
4192 location. By default the TCP Net Console is sent to host at the
4193 port. If you use the ``server=on`` option QEMU will wait for a client
4194 socket application to connect to the port before continuing,
4195 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off``
4196 option disables the Nagle buffering algorithm. The ``reconnect=on``
4197 option only applies if ``server=no`` is set, if the connection goes
4198 down it will attempt to reconnect at the given interval. If host
4199 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a
4200 time is accepted. You can use ``telnet=on`` to connect to the
4201 corresponding character device.
4203 ``Example to send tcp console to 192.168.0.2 port 4444``
4204 -serial tcp:192.168.0.2:4444
4206 ``Example to listen and wait on port 4444 for connection``
4207 -serial tcp::4444,server=on
4209 ``Example to not wait and listen on ip 192.168.0.100 port 4444``
4210 -serial tcp:192.168.0.100:4444,server=on,wait=off
4212 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]``
4213 The telnet protocol is used instead of raw tcp sockets. The
4214 options work the same as if you had specified ``-serial tcp``.
4215 The difference is that the port acts like a telnet server or
4216 client using telnet option negotiation. This will also allow you
4217 to send the MAGIC\_SYSRQ sequence if you use a telnet that
4218 supports sending the break sequence. Typically in unix telnet
4219 you do it with Control-] and then type "send break" followed by
4220 pressing the enter key.
4222 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]``
4223 The WebSocket protocol is used instead of raw tcp socket. The
4224 port acts as a WebSocket server. Client mode is not supported.
4226 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]``
4227 A unix domain socket is used instead of a tcp socket. The option
4228 works the same as if you had specified ``-serial tcp`` except
4229 the unix domain socket path is used for connections.
4231 ``mon:dev_string``
4232 This is a special option to allow the monitor to be multiplexed
4233 onto another serial port. The monitor is accessed with key
4234 sequence of Control-a and then pressing c. dev\_string should be
4235 any one of the serial devices specified above. An example to
4236 multiplex the monitor onto a telnet server listening on port
4237 4444 would be:
4239 ``-serial mon:telnet::4444,server=on,wait=off``
4241 When the monitor is multiplexed to stdio in this way, Ctrl+C
4242 will not terminate QEMU any more but will be passed to the guest
4243 instead.
4245 ``braille``
4246 Braille device. This will use BrlAPI to display the braille
4247 output on a real or fake device.
4249 ``msmouse``
4250 Three button serial mouse. Configure the guest to use Microsoft
4251 protocol.
4252 ERST
4254 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
4255 "-parallel dev redirect the parallel port to char device 'dev'\n",
4256 QEMU_ARCH_ALL)
4257 SRST
4258 ``-parallel dev``
4259 Redirect the virtual parallel port to host device dev (same devices
4260 as the serial port). On Linux hosts, ``/dev/parportN`` can be used
4261 to use hardware devices connected on the corresponding host parallel
4262 port.
4264 This option can be used several times to simulate up to 3 parallel
4265 ports.
4267 Use ``-parallel none`` to disable all parallel ports.
4268 ERST
4270 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
4271 "-monitor dev redirect the monitor to char device 'dev'\n",
4272 QEMU_ARCH_ALL)
4273 SRST
4274 ``-monitor dev``
4275 Redirect the monitor to host device dev (same devices as the serial
4276 port). The default device is ``vc`` in graphical mode and ``stdio``
4277 in non graphical mode. Use ``-monitor none`` to disable the default
4278 monitor.
4279 ERST
4280 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
4281 "-qmp dev like -monitor but opens in 'control' mode\n",
4282 QEMU_ARCH_ALL)
4283 SRST
4284 ``-qmp dev``
4285 Like ``-monitor`` but opens in 'control' mode. For example, to make
4286 QMP available on localhost port 4444::
4288 -qmp tcp:localhost:4444,server=on,wait=off
4290 Not all options are configurable via this syntax; for maximum
4291 flexibility use the ``-mon`` option and an accompanying ``-chardev``.
4293 ERST
4294 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
4295 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
4296 QEMU_ARCH_ALL)
4297 SRST
4298 ``-qmp-pretty dev``
4299 Like ``-qmp`` but uses pretty JSON formatting.
4300 ERST
4302 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
4303 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
4304 SRST
4305 ``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
4306 Set up a monitor connected to the chardev ``name``.
4307 QEMU supports two monitors: the Human Monitor Protocol
4308 (HMP; for human interaction), and the QEMU Monitor Protocol
4309 (QMP; a JSON RPC-style protocol).
4310 The default is HMP; ``mode=control`` selects QMP instead.
4311 ``pretty`` is only valid when ``mode=control``,
4312 turning on JSON pretty printing to ease
4313 human reading and debugging.
4315 For example::
4317 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \
4318 -mon chardev=mon1,mode=control,pretty=on
4320 enables the QMP monitor on localhost port 4444 with pretty-printing.
4321 ERST
4323 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
4324 "-debugcon dev redirect the debug console to char device 'dev'\n",
4325 QEMU_ARCH_ALL)
4326 SRST
4327 ``-debugcon dev``
4328 Redirect the debug console to host device dev (same devices as the
4329 serial port). The debug console is an I/O port which is typically
4330 port 0xe9; writing to that I/O port sends output to this device. The
4331 default device is ``vc`` in graphical mode and ``stdio`` in non
4332 graphical mode.
4333 ERST
4335 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
4336 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
4337 SRST
4338 ``-pidfile file``
4339 Store the QEMU process PID in file. It is useful if you launch QEMU
4340 from a script.
4341 ERST
4343 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
4344 "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL)
4345 SRST
4346 ``-singlestep``
4347 This is a deprecated synonym for the TCG accelerator property
4348 ``one-insn-per-tb``.
4349 ERST
4351 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
4352 "--preconfig pause QEMU before machine is initialized (experimental)\n",
4353 QEMU_ARCH_ALL)
4354 SRST
4355 ``--preconfig``
4356 Pause QEMU for interactive configuration before the machine is
4357 created, which allows querying and configuring properties that will
4358 affect machine initialization. Use QMP command 'x-exit-preconfig' to
4359 exit the preconfig state and move to the next state (i.e. run guest
4360 if -S isn't used or pause the second time if -S is used). This
4361 option is experimental.
4362 ERST
4364 DEF("S", 0, QEMU_OPTION_S, \
4365 "-S freeze CPU at startup (use 'c' to start execution)\n",
4366 QEMU_ARCH_ALL)
4367 SRST
4368 ``-S``
4369 Do not start CPU at startup (you must type 'c' in the monitor).
4370 ERST
4372 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
4373 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
4374 " run qemu with overcommit hints\n"
4375 " mem-lock=on|off controls memory lock support (default: off)\n"
4376 " cpu-pm=on|off controls cpu power management (default: off)\n",
4377 QEMU_ARCH_ALL)
4378 SRST
4379 ``-overcommit mem-lock=on|off``
4381 ``-overcommit cpu-pm=on|off``
4382 Run qemu with hints about host resource overcommit. The default is
4383 to assume that host overcommits all resources.
4385 Locking qemu and guest memory can be enabled via ``mem-lock=on``
4386 (disabled by default). This works when host memory is not
4387 overcommitted and reduces the worst-case latency for guest.
4389 Guest ability to manage power state of host cpus (increasing latency
4390 for other processes on the same host cpu, but decreasing latency for
4391 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This
4392 works best when host CPU is not overcommitted. When used, host
4393 estimates of CPU cycle and power utilization will be incorrect, not
4394 taking into account guest idle time.
4395 ERST
4397 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
4398 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n"
4399 " the guest without waiting for gdb to connect; use -S too\n"
4400 " if you want it to not start execution.)\n",
4401 QEMU_ARCH_ALL)
4402 SRST
4403 ``-gdb dev``
4404 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter
4405 in the System Emulation Users Guide). Note that this option does not pause QEMU
4406 execution -- if you want QEMU to not start the guest until you
4407 connect with gdb and issue a ``continue`` command, you will need to
4408 also pass the ``-S`` option to QEMU.
4410 The most usual configuration is to listen on a local TCP socket::
4412 -gdb tcp::3117
4414 but you can specify other backends; UDP, pseudo TTY, or even stdio
4415 are all reasonable use cases. For example, a stdio connection
4416 allows you to start QEMU from within gdb and establish the
4417 connection via a pipe:
4419 .. parsed-literal::
4421 (gdb) target remote | exec |qemu_system| -gdb stdio ...
4422 ERST
4424 DEF("s", 0, QEMU_OPTION_s, \
4425 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
4426 QEMU_ARCH_ALL)
4427 SRST
4428 ``-s``
4429 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
4430 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide).
4431 ERST
4433 DEF("d", HAS_ARG, QEMU_OPTION_d, \
4434 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
4435 QEMU_ARCH_ALL)
4436 SRST
4437 ``-d item1[,...]``
4438 Enable logging of specified items. Use '-d help' for a list of log
4439 items.
4440 ERST
4442 DEF("D", HAS_ARG, QEMU_OPTION_D, \
4443 "-D logfile output log to logfile (default stderr)\n",
4444 QEMU_ARCH_ALL)
4445 SRST
4446 ``-D logfile``
4447 Output log in logfile instead of to stderr
4448 ERST
4450 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
4451 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
4452 QEMU_ARCH_ALL)
4453 SRST
4454 ``-dfilter range1[,...]``
4455 Filter debug output to that relevant to a range of target addresses.
4456 The filter spec can be either start+size, start-size or start..end
4457 where start end and size are the addresses and sizes required. For
4458 example:
4462 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
4464 Will dump output for any code in the 0x1000 sized block starting at
4465 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and
4466 another 0x1000 sized block starting at 0xffffffc00005f000.
4467 ERST
4469 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
4470 "-seed number seed the pseudo-random number generator\n",
4471 QEMU_ARCH_ALL)
4472 SRST
4473 ``-seed number``
4474 Force the guest to use a deterministic pseudo-random number
4475 generator, seeded with number. This does not affect crypto routines
4476 within the host.
4477 ERST
4479 DEF("L", HAS_ARG, QEMU_OPTION_L, \
4480 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
4481 QEMU_ARCH_ALL)
4482 SRST
4483 ``-L path``
4484 Set the directory for the BIOS, VGA BIOS and keymaps.
4486 To list all the data directories, use ``-L help``.
4487 ERST
4489 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
4490 "-enable-kvm enable KVM full virtualization support\n",
4491 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC |
4492 QEMU_ARCH_RISCV | QEMU_ARCH_S390X)
4493 SRST
4494 ``-enable-kvm``
4495 Enable KVM full virtualization support. This option is only
4496 available if KVM support is enabled when compiling.
4497 ERST
4499 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
4500 "-xen-domid id specify xen guest domain id\n",
4501 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4502 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
4503 "-xen-attach attach to existing xen domain\n"
4504 " libxl will use this when starting QEMU\n",
4505 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4506 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
4507 "-xen-domid-restrict restrict set of available xen operations\n"
4508 " to specified domain id. (Does not affect\n"
4509 " xenpv machine type).\n",
4510 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4511 SRST
4512 ``-xen-domid id``
4513 Specify xen guest domain id (XEN only).
4515 ``-xen-attach``
4516 Attach to existing xen domain. libxl will use this when starting
4517 QEMU (XEN only). Restrict set of available xen operations to
4518 specified domain id (XEN only).
4519 ERST
4521 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
4522 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
4523 SRST
4524 ``-no-reboot``
4525 Exit instead of rebooting.
4526 ERST
4528 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
4529 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
4530 SRST
4531 ``-no-shutdown``
4532 Don't exit QEMU on guest shutdown, but instead only stop the
4533 emulation. This allows for instance switching to monitor to commit
4534 changes to the disk image.
4535 ERST
4537 DEF("action", HAS_ARG, QEMU_OPTION_action,
4538 "-action reboot=reset|shutdown\n"
4539 " action when guest reboots [default=reset]\n"
4540 "-action shutdown=poweroff|pause\n"
4541 " action when guest shuts down [default=poweroff]\n"
4542 "-action panic=pause|shutdown|exit-failure|none\n"
4543 " action when guest panics [default=shutdown]\n"
4544 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
4545 " action when watchdog fires [default=reset]\n",
4546 QEMU_ARCH_ALL)
4547 SRST
4548 ``-action event=action``
4549 The action parameter serves to modify QEMU's default behavior when
4550 certain guest events occur. It provides a generic method for specifying the
4551 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown``
4552 parameters.
4554 Examples:
4556 ``-action panic=none``
4557 ``-action reboot=shutdown,shutdown=pause``
4558 ``-device i6300esb -action watchdog=pause``
4560 ERST
4562 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
4563 "-loadvm [tag|id]\n" \
4564 " start right away with a saved state (loadvm in monitor)\n",
4565 QEMU_ARCH_ALL)
4566 SRST
4567 ``-loadvm file``
4568 Start right away with a saved state (``loadvm`` in monitor)
4569 ERST
4571 #ifndef _WIN32
4572 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
4573 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
4574 #endif
4575 SRST
4576 ``-daemonize``
4577 Daemonize the QEMU process after initialization. QEMU will not
4578 detach from standard IO until it is ready to receive connections on
4579 any of its devices. This option is a useful way for external
4580 programs to launch QEMU without having to cope with initialization
4581 race conditions.
4582 ERST
4584 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
4585 "-option-rom rom load a file, rom, into the option ROM space\n",
4586 QEMU_ARCH_ALL)
4587 SRST
4588 ``-option-rom file``
4589 Load the contents of file as an option ROM. This option is useful to
4590 load things like EtherBoot.
4591 ERST
4593 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
4594 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
4595 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
4596 QEMU_ARCH_ALL)
4598 SRST
4599 ``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]``
4600 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at
4601 the current UTC or local time, respectively. ``localtime`` is
4602 required for correct date in MS-DOS or Windows. To start at a
4603 specific point in time, provide datetime in the format
4604 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC.
4606 By default the RTC is driven by the host system time. This allows
4607 using of the RTC as accurate reference clock inside the guest,
4608 specifically if the host time is smoothly following an accurate
4609 external reference clock, e.g. via NTP. If you want to isolate the
4610 guest time from the host, you can set ``clock`` to ``rt`` instead,
4611 which provides a host monotonic clock if host support it. To even
4612 prevent the RTC from progressing during suspension, you can set
4613 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is
4614 recommended especially in icount mode in order to preserve
4615 determinism; however, note that in icount mode the speed of the
4616 virtual clock is variable and can in general differ from the host
4617 clock.
4619 Enable ``driftfix`` (i386 targets only) if you experience time drift
4620 problems, specifically with Windows' ACPI HAL. This option will try
4621 to figure out how many timer interrupts were not processed by the
4622 Windows guest and will re-inject them.
4623 ERST
4625 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
4626 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \
4627 " enable virtual instruction counter with 2^N clock ticks per\n" \
4628 " instruction, enable aligning the host and virtual clocks\n" \
4629 " or disable real time cpu sleeping, and optionally enable\n" \
4630 " record-and-replay mode\n", QEMU_ARCH_ALL)
4631 SRST
4632 ``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]``
4633 Enable virtual instruction counter. The virtual cpu will execute one
4634 instruction every 2^N ns of virtual time. If ``auto`` is specified
4635 then the virtual cpu speed will be automatically adjusted to keep
4636 virtual time within a few seconds of real time.
4638 Note that while this option can give deterministic behavior, it does
4639 not provide cycle accurate emulation. Modern CPUs contain
4640 superscalar out of order cores with complex cache hierarchies. The
4641 number of instructions executed often has little or no correlation
4642 with actual performance.
4644 When the virtual cpu is sleeping, the virtual time will advance at
4645 default speed unless ``sleep=on`` is specified. With
4646 ``sleep=on``, the virtual time will jump to the next timer
4647 deadline instantly whenever the virtual cpu goes to sleep mode and
4648 will not advance if no timer is enabled. This behavior gives
4649 deterministic execution times from the guest point of view.
4650 The default if icount is enabled is ``sleep=off``.
4651 ``sleep=on`` cannot be used together with either ``shift=auto``
4652 or ``align=on``.
4654 ``align=on`` will activate the delay algorithm which will try to
4655 synchronise the host clock and the virtual clock. The goal is to
4656 have a guest running at the real frequency imposed by the shift
4657 option. Whenever the guest clock is behind the host clock and if
4658 ``align=on`` is specified then we print a message to the user to
4659 inform about the delay. Currently this option does not work when
4660 ``shift`` is ``auto``. Note: The sync algorithm will work for those
4661 shift values for which the guest clock runs ahead of the host clock.
4662 Typically this happens when the shift value is high (how high
4663 depends on the host machine). The default if icount is enabled
4664 is ``align=off``.
4666 When the ``rr`` option is specified deterministic record/replay is
4667 enabled. The ``rrfile=`` option must also be provided to
4668 specify the path to the replay log. In record mode data is written
4669 to this file, and in replay mode it is read back.
4670 If the ``rrsnapshot`` option is given then it specifies a VM snapshot
4671 name. In record mode, a new VM snapshot with the given name is created
4672 at the start of execution recording. In replay mode this option
4673 specifies the snapshot name used to load the initial VM state.
4674 ERST
4676 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
4677 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
4678 " action when watchdog fires [default=reset]\n",
4679 QEMU_ARCH_ALL)
4680 SRST
4681 ``-watchdog-action action``
4682 The action controls what QEMU will do when the watchdog timer
4683 expires. The default is ``reset`` (forcefully reset the guest).
4684 Other possible actions are: ``shutdown`` (attempt to gracefully
4685 shutdown the guest), ``poweroff`` (forcefully poweroff the guest),
4686 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the
4687 guest), ``debug`` (print a debug message and continue), or ``none``
4688 (do nothing).
4690 Note that the ``shutdown`` action requires that the guest responds
4691 to ACPI signals, which it may not be able to do in the sort of
4692 situations where the watchdog would have expired, and thus
4693 ``-watchdog-action shutdown`` is not recommended for production use.
4695 Examples:
4697 ``-device i6300esb -watchdog-action pause``
4699 ERST
4701 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
4702 "-echr chr set terminal escape character instead of ctrl-a\n",
4703 QEMU_ARCH_ALL)
4704 SRST
4705 ``-echr numeric_ascii_value``
4706 Change the escape character used for switching to the monitor when
4707 using monitor and serial sharing. The default is ``0x01`` when using
4708 the ``-nographic`` option. ``0x01`` is equal to pressing
4709 ``Control-a``. You can select a different character from the ascii
4710 control keys where 1 through 26 map to Control-a through Control-z.
4711 For instance you could use the either of the following to change the
4712 escape character to Control-t.
4714 ``-echr 0x14``; \ ``-echr 20``
4716 ERST
4718 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4719 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
4720 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \
4721 "-incoming unix:socketpath\n" \
4722 " prepare for incoming migration, listen on\n" \
4723 " specified protocol and socket address\n" \
4724 "-incoming fd:fd\n" \
4725 "-incoming file:filename[,offset=offset]\n" \
4726 "-incoming exec:cmdline\n" \
4727 " accept incoming migration on given file descriptor\n" \
4728 " or from given external command\n" \
4729 "-incoming defer\n" \
4730 " wait for the URI to be specified via migrate_incoming\n",
4731 QEMU_ARCH_ALL)
4732 SRST
4733 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
4735 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
4736 Prepare for incoming migration, listen on a given tcp port.
4738 ``-incoming unix:socketpath``
4739 Prepare for incoming migration, listen on a given unix socket.
4741 ``-incoming fd:fd``
4742 Accept incoming migration from a given file descriptor.
4744 ``-incoming file:filename[,offset=offset]``
4745 Accept incoming migration from a given file starting at offset.
4746 offset allows the common size suffixes, or a 0x prefix, but not both.
4748 ``-incoming exec:cmdline``
4749 Accept incoming migration as an output from specified external
4750 command.
4752 ``-incoming defer``
4753 Wait for the URI to be specified via migrate\_incoming. The monitor
4754 can be used to change settings (such as migration parameters) prior
4755 to issuing the migrate\_incoming to allow the migration to begin.
4756 ERST
4758 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4759 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4760 SRST
4761 ``-only-migratable``
4762 Only allow migratable devices. Devices will not be allowed to enter
4763 an unmigratable state.
4764 ERST
4766 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4767 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4768 SRST
4769 ``-nodefaults``
4770 Don't create default devices. Normally, QEMU sets the default
4771 devices like serial port, parallel port, virtual console, monitor
4772 device, VGA adapter, floppy and CD-ROM drive and others. The
4773 ``-nodefaults`` option will disable all those default devices.
4774 ERST
4776 #ifndef _WIN32
4777 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4778 "-chroot dir chroot to dir just before starting the VM (deprecated)\n",
4779 QEMU_ARCH_ALL)
4780 #endif
4781 SRST
4782 ``-chroot dir``
4783 Deprecated, use '-run-with chroot=...' instead.
4784 Immediately before starting guest execution, chroot to the specified
4785 directory. Especially useful in combination with -runas.
4786 ERST
4788 #ifndef _WIN32
4789 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4790 "-runas user change to user id user just before starting the VM\n" \
4791 " user can be numeric uid:gid instead\n",
4792 QEMU_ARCH_ALL)
4793 #endif
4794 SRST
4795 ``-runas user``
4796 Immediately before starting guest execution, drop root privileges,
4797 switching to the specified user.
4798 ERST
4800 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4801 "-prom-env variable=value\n"
4802 " set OpenBIOS nvram variables\n",
4803 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4804 SRST
4805 ``-prom-env variable=value``
4806 Set OpenBIOS nvram variable to given value (PPC, SPARC only).
4810 qemu-system-sparc -prom-env 'auto-boot?=false' \
4811 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
4815 qemu-system-ppc -prom-env 'auto-boot?=false' \
4816 -prom-env 'boot-device=hd:2,\yaboot' \
4817 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
4818 ERST
4819 DEF("semihosting", 0, QEMU_OPTION_semihosting,
4820 "-semihosting semihosting mode\n",
4821 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4822 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4823 SRST
4824 ``-semihosting``
4825 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only).
4827 .. warning::
4828 Note that this allows guest direct access to the host filesystem, so
4829 should only be used with a trusted guest OS.
4831 See the -semihosting-config option documentation for further
4832 information about the facilities this enables.
4833 ERST
4834 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4835 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \
4836 " semihosting configuration\n",
4837 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4838 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4839 SRST
4840 ``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]``
4841 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V
4842 only).
4844 .. warning::
4845 Note that this allows guest direct access to the host filesystem, so
4846 should only be used with a trusted guest OS.
4848 ``target=native|gdb|auto``
4849 Defines where the semihosting calls will be addressed, to QEMU
4850 (``native``) or to GDB (``gdb``). The default is ``auto``, which
4851 means ``gdb`` during debug sessions and ``native`` otherwise.
4853 ``chardev=str1``
4854 Send the output to a chardev backend output for native or auto
4855 output when not in gdb
4857 ``userspace=on|off``
4858 Allows code running in guest userspace to access the semihosting
4859 interface. The default is that only privileged guest code can
4860 make semihosting calls. Note that setting ``userspace=on`` should
4861 only be used if all guest code is trusted (for example, in
4862 bare-metal test case code).
4864 ``arg=str1,arg=str2,...``
4865 Allows the user to pass input arguments, and can be used
4866 multiple times to build up a list. The old-style
4867 ``-kernel``/``-append`` method of passing a command line is
4868 still supported for backward compatibility. If both the
4869 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are
4870 specified, the former is passed to semihosting as it always
4871 takes precedence.
4872 ERST
4873 DEF("old-param", 0, QEMU_OPTION_old_param,
4874 "-old-param old param mode\n", QEMU_ARCH_ARM)
4875 SRST
4876 ``-old-param``
4877 Old param mode (ARM only).
4878 ERST
4880 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4881 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4882 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4883 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4884 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4885 " by the kernel, but typically no longer used by modern\n" \
4886 " C library implementations.\n" \
4887 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \
4888 " to elevate privileges using set*uid|gid system calls.\n" \
4889 " The value 'children' will deny set*uid|gid system calls for\n" \
4890 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4891 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4892 " blocking *fork and execve\n" \
4893 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4894 QEMU_ARCH_ALL)
4895 SRST
4896 ``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]``
4897 Enable Seccomp mode 2 system call filter. 'on' will enable syscall
4898 filtering and 'off' will disable it. The default is 'off'.
4900 ``obsolete=string``
4901 Enable Obsolete system calls
4903 ``elevateprivileges=string``
4904 Disable set\*uid\|gid system calls
4906 ``spawn=string``
4907 Disable \*fork and execve
4909 ``resourcecontrol=string``
4910 Disable process affinity and schedular priority
4911 ERST
4913 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4914 "-readconfig <file>\n"
4915 " read config file\n", QEMU_ARCH_ALL)
4916 SRST
4917 ``-readconfig file``
4918 Read device configuration from file. This approach is useful when
4919 you want to spawn QEMU process with many command line options but
4920 you don't want to exceed the command line character limit.
4921 ERST
4923 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4924 "-no-user-config\n"
4925 " do not load default user-provided config files at startup\n",
4926 QEMU_ARCH_ALL)
4927 SRST
4928 ``-no-user-config``
4929 The ``-no-user-config`` option makes QEMU not load any of the
4930 user-provided config files on sysconfdir.
4931 ERST
4933 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4934 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4935 " specify tracing options\n",
4936 QEMU_ARCH_ALL)
4937 SRST
4938 ``-trace [[enable=]pattern][,events=file][,file=file]``
4939 .. include:: ../qemu-option-trace.rst.inc
4941 ERST
4942 DEF("plugin", HAS_ARG, QEMU_OPTION_plugin,
4943 "-plugin [file=]<file>[,<argname>=<argvalue>]\n"
4944 " load a plugin\n",
4945 QEMU_ARCH_ALL)
4946 SRST
4947 ``-plugin file=file[,argname=argvalue]``
4948 Load a plugin.
4950 ``file=file``
4951 Load the given plugin from a shared library file.
4953 ``argname=argvalue``
4954 Argument passed to the plugin. (Can be given multiple times.)
4955 ERST
4957 HXCOMM Internal use
4958 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4959 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4961 #ifdef __linux__
4962 DEF("async-teardown", 0, QEMU_OPTION_asyncteardown,
4963 "-async-teardown enable asynchronous teardown\n",
4964 QEMU_ARCH_ALL)
4965 SRST
4966 ``-async-teardown``
4967 This option is deprecated and should no longer be used. The new option
4968 ``-run-with async-teardown=on`` is a replacement.
4969 ERST
4970 #endif
4971 #ifdef CONFIG_POSIX
4972 DEF("run-with", HAS_ARG, QEMU_OPTION_run_with,
4973 "-run-with [async-teardown=on|off][,chroot=dir]\n"
4974 " Set miscellaneous QEMU process lifecycle options:\n"
4975 " async-teardown=on enables asynchronous teardown (Linux only)\n"
4976 " chroot=dir chroot to dir just before starting the VM\n",
4977 QEMU_ARCH_ALL)
4978 SRST
4979 ``-run-with [async-teardown=on|off][,chroot=dir]``
4980 Set QEMU process lifecycle options.
4982 ``async-teardown=on`` enables asynchronous teardown. A new process called
4983 "cleanup/<QEMU_PID>" will be created at startup sharing the address
4984 space with the main QEMU process, using clone. It will wait for the
4985 main QEMU process to terminate completely, and then exit. This allows
4986 QEMU to terminate very quickly even if the guest was huge, leaving the
4987 teardown of the address space to the cleanup process. Since the cleanup
4988 process shares the same cgroups as the main QEMU process, accounting is
4989 performed correctly. This only works if the cleanup process is not
4990 forcefully killed with SIGKILL before the main QEMU process has
4991 terminated completely.
4993 ``chroot=dir`` can be used for doing a chroot to the specified directory
4994 immediately before starting the guest execution. This is especially useful
4995 in combination with -runas.
4996 ERST
4997 #endif
4999 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
5000 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
5001 " control error message format\n"
5002 " timestamp=on enables timestamps (default: off)\n"
5003 " guest-name=on enables guest name prefix but only if\n"
5004 " -name guest option is set (default: off)\n",
5005 QEMU_ARCH_ALL)
5006 SRST
5007 ``-msg [timestamp[=on|off]][,guest-name[=on|off]]``
5008 Control error message format.
5010 ``timestamp=on|off``
5011 Prefix messages with a timestamp. Default is off.
5013 ``guest-name=on|off``
5014 Prefix messages with guest name but only if -name guest option is set
5015 otherwise the option is ignored. Default is off.
5016 ERST
5018 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
5019 "-dump-vmstate <file>\n"
5020 " Output vmstate information in JSON format to file.\n"
5021 " Use the scripts/vmstate-static-checker.py file to\n"
5022 " check for possible regressions in migration code\n"
5023 " by comparing two such vmstate dumps.\n",
5024 QEMU_ARCH_ALL)
5025 SRST
5026 ``-dump-vmstate file``
5027 Dump json-encoded vmstate information for current machine type to
5028 file in file
5029 ERST
5031 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
5032 "-enable-sync-profile\n"
5033 " enable synchronization profiling\n",
5034 QEMU_ARCH_ALL)
5035 SRST
5036 ``-enable-sync-profile``
5037 Enable synchronization profiling.
5038 ERST
5040 #if defined(CONFIG_TCG) && defined(CONFIG_LINUX)
5041 DEF("perfmap", 0, QEMU_OPTION_perfmap,
5042 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n",
5043 QEMU_ARCH_ALL)
5044 SRST
5045 ``-perfmap``
5046 Generate a map file for Linux perf tools that will allow basic profiling
5047 information to be broken down into basic blocks.
5048 ERST
5050 DEF("jitdump", 0, QEMU_OPTION_jitdump,
5051 "-jitdump generate a jit-${pid}.dump file for perf\n",
5052 QEMU_ARCH_ALL)
5053 SRST
5054 ``-jitdump``
5055 Generate a dump file for Linux perf tools that maps basic blocks to symbol
5056 names, line numbers and JITted code.
5057 ERST
5058 #endif
5060 DEFHEADING()
5062 DEFHEADING(Generic object creation:)
5064 DEF("object", HAS_ARG, QEMU_OPTION_object,
5065 "-object TYPENAME[,PROP1=VALUE1,...]\n"
5066 " create a new object of type TYPENAME setting properties\n"
5067 " in the order they are specified. Note that the 'id'\n"
5068 " property must be set. These objects are placed in the\n"
5069 " '/objects' path.\n",
5070 QEMU_ARCH_ALL)
5071 SRST
5072 ``-object typename[,prop1=value1,...]``
5073 Create a new object of type typename setting properties in the order
5074 they are specified. Note that the 'id' property must be set. These
5075 objects are placed in the '/objects' path.
5077 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,offset=offset,readonly=on|off,rom=on|off|auto``
5078 Creates a memory file backend object, which can be used to back
5079 the guest RAM with huge pages.
5081 The ``id`` parameter is a unique ID that will be used to
5082 reference this memory region in other parameters, e.g. ``-numa``,
5083 ``-device nvdimm``, etc.
5085 The ``size`` option provides the size of the memory region, and
5086 accepts common suffixes, e.g. ``500M``.
5088 The ``mem-path`` provides the path to either a shared memory or
5089 huge page filesystem mount.
5091 The ``share`` boolean option determines whether the memory
5092 region is marked as private to QEMU, or shared. The latter
5093 allows a co-operating external process to access the QEMU memory
5094 region.
5096 The ``share`` is also required for pvrdma devices due to
5097 limitations in the RDMA API provided by Linux.
5099 Setting share=on might affect the ability to configure NUMA
5100 bindings for the memory backend under some circumstances, see
5101 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel
5102 source tree for additional details.
5104 Setting the ``discard-data`` boolean option to on indicates that
5105 file contents can be destroyed when QEMU exits, to avoid
5106 unnecessarily flushing data to the backing file. Note that
5107 ``discard-data`` is only an optimization, and QEMU might not
5108 discard file contents if it aborts unexpectedly or is terminated
5109 using SIGKILL.
5111 The ``merge`` boolean option enables memory merge, also known as
5112 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider
5113 the pages for memory deduplication.
5115 Setting the ``dump`` boolean option to off excludes the memory
5116 from core dumps. This feature is also known as MADV\_DONTDUMP.
5118 The ``prealloc`` boolean option enables memory preallocation.
5120 The ``host-nodes`` option binds the memory range to a list of
5121 NUMA host nodes.
5123 The ``policy`` option sets the NUMA policy to one of the
5124 following values:
5126 ``default``
5127 default host policy
5129 ``preferred``
5130 prefer the given host node list for allocation
5132 ``bind``
5133 restrict memory allocation to the given host node list
5135 ``interleave``
5136 interleave memory allocations across the given host node
5137 list
5139 The ``align`` option specifies the base address alignment when
5140 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg
5141 ``2M``. Some backend store specified by ``mem-path`` requires an
5142 alignment different than the default one used by QEMU, eg the
5143 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
5144 such cases, users can specify the required alignment via this
5145 option.
5147 The ``offset`` option specifies the offset into the target file
5148 that the region starts at. You can use this parameter to back
5149 multiple regions with a single file.
5151 The ``pmem`` option specifies whether the backing file specified
5152 by ``mem-path`` is in host persistent memory that can be
5153 accessed using the SNIA NVM programming model (e.g. Intel
5154 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary
5155 operations to guarantee the persistence of its own writes to
5156 ``mem-path`` (e.g. in vNVDIMM label emulation and live
5157 migration). Also, we will map the backend-file with MAP\_SYNC
5158 flag, which ensures the file metadata is in sync for
5159 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC
5160 requires support from both the host kernel (since Linux kernel
5161 4.15) and the filesystem of ``mem-path`` mounted with DAX
5162 option.
5164 The ``readonly`` option specifies whether the backing file is opened
5165 read-only or read-write (default).
5167 The ``rom`` option specifies whether to create Read Only Memory
5168 (ROM) that cannot be modified by the VM. Any write attempts to such
5169 ROM will be denied. Most use cases want proper RAM instead of ROM.
5170 However, selected use cases, like R/O NVDIMMs, can benefit from
5171 ROM. If set to ``on``, create ROM; if set to ``off``, create
5172 writable RAM; if set to ``auto`` (default), the value of the
5173 ``readonly`` option is used. This option is primarily helpful when
5174 we want to have writable RAM in configurations that would
5175 traditionally create ROM before the ``rom`` option was introduced:
5176 VM templating, where we want to open a file readonly
5177 (``readonly=on``) and mark the memory to be private for QEMU
5178 (``share=off``). For this use case, we need writable RAM instead
5179 of ROM, and want to also set ``rom=off``.
5181 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave``
5182 Creates a memory backend object, which can be used to back the
5183 guest RAM. Memory backend objects offer more control than the
5184 ``-m`` option that is traditionally used to define guest RAM.
5185 Please refer to ``memory-backend-file`` for a description of the
5186 options.
5188 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size``
5189 Creates an anonymous memory file backend object, which allows
5190 QEMU to share the memory with an external process (e.g. when
5191 using vhost-user). The memory is allocated with memfd and
5192 optional sealing. (Linux only)
5194 The ``seal`` option creates a sealed-file, that will block
5195 further resizing the memory ('on' by default).
5197 The ``hugetlb`` option specify the file to be created resides in
5198 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction
5199 with the ``hugetlb`` option, the ``hugetlbsize`` option specify
5200 the hugetlb page size on systems that support multiple hugetlb
5201 page sizes (it must be a power of 2 value supported by the
5202 system).
5204 In some versions of Linux, the ``hugetlb`` option is
5205 incompatible with the ``seal`` option (requires at least Linux
5206 4.16).
5208 Please refer to ``memory-backend-file`` for a description of the
5209 other options.
5211 The ``share`` boolean option is on by default with memfd.
5213 ``-object rng-builtin,id=id``
5214 Creates a random number generator backend which obtains entropy
5215 from QEMU builtin functions. The ``id`` parameter is a unique ID
5216 that will be used to reference this entropy backend from the
5217 ``virtio-rng`` device. By default, the ``virtio-rng`` device
5218 uses this RNG backend.
5220 ``-object rng-random,id=id,filename=/dev/random``
5221 Creates a random number generator backend which obtains entropy
5222 from a device on the host. The ``id`` parameter is a unique ID
5223 that will be used to reference this entropy backend from the
5224 ``virtio-rng`` device. The ``filename`` parameter specifies
5225 which file to obtain entropy from and if omitted defaults to
5226 ``/dev/urandom``.
5228 ``-object rng-egd,id=id,chardev=chardevid``
5229 Creates a random number generator backend which obtains entropy
5230 from an external daemon running on the host. The ``id``
5231 parameter is a unique ID that will be used to reference this
5232 entropy backend from the ``virtio-rng`` device. The ``chardev``
5233 parameter is the unique ID of a character device backend that
5234 provides the connection to the RNG daemon.
5236 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off``
5237 Creates a TLS anonymous credentials object, which can be used to
5238 provide TLS support on network backends. The ``id`` parameter is
5239 a unique ID which network backends will use to access the
5240 credentials. The ``endpoint`` is either ``server`` or ``client``
5241 depending on whether the QEMU network backend that uses the
5242 credentials will be acting as a client or as a server. If
5243 ``verify-peer`` is enabled (the default) then once the handshake
5244 is completed, the peer credentials will be verified, though this
5245 is a no-op for anonymous credentials.
5247 The dir parameter tells QEMU where to find the credential files.
5248 For server endpoints, this directory may contain a file
5249 dh-params.pem providing diffie-hellman parameters to use for the
5250 TLS server. If the file is missing, QEMU will generate a set of
5251 DH parameters at startup. This is a computationally expensive
5252 operation that consumes random pool entropy, so it is
5253 recommended that a persistent set of parameters be generated
5254 upfront and saved.
5256 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]``
5257 Creates a TLS Pre-Shared Keys (PSK) credentials object, which
5258 can be used to provide TLS support on network backends. The
5259 ``id`` parameter is a unique ID which network backends will use
5260 to access the credentials. The ``endpoint`` is either ``server``
5261 or ``client`` depending on whether the QEMU network backend that
5262 uses the credentials will be acting as a client or as a server.
5263 For clients only, ``username`` is the username which will be
5264 sent to the server. If omitted it defaults to "qemu".
5266 The dir parameter tells QEMU where to find the keys file. It is
5267 called "dir/keys.psk" and contains "username:key" pairs. This
5268 file can most easily be created using the GnuTLS ``psktool``
5269 program.
5271 For server endpoints, dir may also contain a file dh-params.pem
5272 providing diffie-hellman parameters to use for the TLS server.
5273 If the file is missing, QEMU will generate a set of DH
5274 parameters at startup. This is a computationally expensive
5275 operation that consumes random pool entropy, so it is
5276 recommended that a persistent set of parameters be generated up
5277 front and saved.
5279 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id``
5280 Creates a TLS anonymous credentials object, which can be used to
5281 provide TLS support on network backends. The ``id`` parameter is
5282 a unique ID which network backends will use to access the
5283 credentials. The ``endpoint`` is either ``server`` or ``client``
5284 depending on whether the QEMU network backend that uses the
5285 credentials will be acting as a client or as a server. If
5286 ``verify-peer`` is enabled (the default) then once the handshake
5287 is completed, the peer credentials will be verified. With x509
5288 certificates, this implies that the clients must be provided
5289 with valid client certificates too.
5291 The dir parameter tells QEMU where to find the credential files.
5292 For server endpoints, this directory may contain a file
5293 dh-params.pem providing diffie-hellman parameters to use for the
5294 TLS server. If the file is missing, QEMU will generate a set of
5295 DH parameters at startup. This is a computationally expensive
5296 operation that consumes random pool entropy, so it is
5297 recommended that a persistent set of parameters be generated
5298 upfront and saved.
5300 For x509 certificate credentials the directory will contain
5301 further files providing the x509 certificates. The certificates
5302 must be stored in PEM format, in filenames ca-cert.pem,
5303 ca-crl.pem (optional), server-cert.pem (only servers),
5304 server-key.pem (only servers), client-cert.pem (only clients),
5305 and client-key.pem (only clients).
5307 For the server-key.pem and client-key.pem files which contain
5308 sensitive private keys, it is possible to use an encrypted
5309 version by providing the passwordid parameter. This provides the
5310 ID of a previously created ``secret`` object containing the
5311 password for decryption.
5313 The priority parameter allows to override the global default
5314 priority used by gnutls. This can be useful if the system
5315 administrator needs to use a weaker set of crypto priorities for
5316 QEMU without potentially forcing the weakness onto all
5317 applications. Or conversely if one wants wants a stronger
5318 default for QEMU than for all other applications, they can do
5319 this through this parameter. Its format is a gnutls priority
5320 string as described at
5321 https://gnutls.org/manual/html_node/Priority-Strings.html.
5323 ``-object tls-cipher-suites,id=id,priority=priority``
5324 Creates a TLS cipher suites object, which can be used to control
5325 the TLS cipher/protocol algorithms that applications are permitted
5326 to use.
5328 The ``id`` parameter is a unique ID which frontends will use to
5329 access the ordered list of permitted TLS cipher suites from the
5330 host.
5332 The ``priority`` parameter allows to override the global default
5333 priority used by gnutls. This can be useful if the system
5334 administrator needs to use a weaker set of crypto priorities for
5335 QEMU without potentially forcing the weakness onto all
5336 applications. Or conversely if one wants wants a stronger
5337 default for QEMU than for all other applications, they can do
5338 this through this parameter. Its format is a gnutls priority
5339 string as described at
5340 https://gnutls.org/manual/html_node/Priority-Strings.html.
5342 An example of use of this object is to control UEFI HTTPS Boot.
5343 The tls-cipher-suites object exposes the ordered list of permitted
5344 TLS cipher suites from the host side to the guest firmware, via
5345 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER
5346 objects. The firmware uses the IANA_TLS_CIPHER array for configuring
5347 guest-side TLS.
5349 In the following example, the priority at which the host-side policy
5350 is retrieved is given by the ``priority`` property.
5351 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to
5352 refer to /etc/crypto-policies/back-ends/gnutls.config.
5354 .. parsed-literal::
5356 # |qemu_system| \\
5357 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\
5358 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
5360 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
5361 Interval t can't be 0, this filter batches the packet delivery:
5362 all packets arriving in a given interval on netdev netdevid are
5363 delayed until the end of the interval. Interval is in
5364 microseconds. ``status`` is optional that indicate whether the
5365 netfilter is on (enabled) or off (disabled), the default status
5366 for netfilter will be 'on'.
5368 queue all\|rx\|tx is an option that can be applied to any
5369 netfilter.
5371 ``all``: the filter is attached both to the receive and the
5372 transmit queue of the netdev (default).
5374 ``rx``: the filter is attached to the receive queue of the
5375 netdev, where it will receive packets sent to the netdev.
5377 ``tx``: the filter is attached to the transmit queue of the
5378 netdev, where it will receive packets sent by the netdev.
5380 position head\|tail\|id=<id> is an option to specify where the
5381 filter should be inserted in the filter list. It can be applied
5382 to any netfilter.
5384 ``head``: the filter is inserted at the head of the filter list,
5385 before any existing filters.
5387 ``tail``: the filter is inserted at the tail of the filter list,
5388 behind any existing filters (default).
5390 ``id=<id>``: the filter is inserted before or behind the filter
5391 specified by <id>, see the insert option below.
5393 insert behind\|before is an option to specify where to insert
5394 the new filter relative to the one specified with
5395 position=id=<id>. It can be applied to any netfilter.
5397 ``before``: insert before the specified filter.
5399 ``behind``: insert behind the specified filter (default).
5401 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5402 filter-mirror on netdev netdevid,mirror net packet to
5403 chardevchardevid, if it has the vnet\_hdr\_support flag,
5404 filter-mirror will mirror packet with vnet\_hdr\_len.
5406 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5407 filter-redirector on netdev netdevid,redirect filter's net
5408 packet to chardev chardevid,and redirect indev's packet to
5409 filter.if it has the vnet\_hdr\_support flag, filter-redirector
5410 will redirect packet with vnet\_hdr\_len. Create a
5411 filter-redirector we need to differ outdev id from indev id, id
5412 can not be the same. we can just use indev or outdev, but at
5413 least one of indev or outdev need to be specified.
5415 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5416 Filter-rewriter is a part of COLO project.It will rewrite tcp
5417 packet to secondary from primary to keep secondary tcp
5418 connection,and rewrite tcp packet to primary from secondary make
5419 tcp packet can be handled by client.if it has the
5420 vnet\_hdr\_support flag, we can parse packet with vnet header.
5422 usage: colo secondary: -object
5423 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object
5424 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object
5425 filter-rewriter,id=rew0,netdev=hn0,queue=all
5427 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]``
5428 Dump the network traffic on netdev dev to the file specified by
5429 filename. At most len bytes (64k by default) per packet are
5430 stored. The file format is libpcap, so it can be analyzed with
5431 tools such as tcpdump or Wireshark.
5433 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]``
5434 Colo-compare gets packet from primary\_in chardevid and
5435 secondary\_in, then compare whether the payload of primary packet
5436 and secondary packet are the same. If same, it will output
5437 primary packet to out\_dev, else it will notify COLO-framework to do
5438 checkpoint and send primary packet to out\_dev. In order to
5439 improve efficiency, we need to put the task of comparison in
5440 another iothread. If it has the vnet\_hdr\_support flag,
5441 colo compare will send/recv packet with vnet\_hdr\_len.
5442 The compare\_timeout=@var{ms} determines the maximum time of the
5443 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms}
5444 is to set the period of scanning expired primary node network packets.
5445 The max\_queue\_size=@var{size} is to set the max compare queue
5446 size depend on user environment.
5447 If user want to use Xen COLO, need to add the notify\_dev to
5448 notify Xen colo-frame to do checkpoint.
5450 COLO-compare must be used with the help of filter-mirror,
5451 filter-redirector and filter-rewriter.
5455 KVM COLO
5457 primary:
5458 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5459 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5460 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5461 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5462 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5463 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5464 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5465 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5466 -object iothread,id=iothread1
5467 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5468 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5469 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5470 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
5472 secondary:
5473 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5474 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5475 -chardev socket,id=red0,host=3.3.3.3,port=9003
5476 -chardev socket,id=red1,host=3.3.3.3,port=9004
5477 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5478 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5481 Xen COLO
5483 primary:
5484 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5485 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5486 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5487 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5488 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5489 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5490 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5491 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5492 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off
5493 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5494 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5495 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5496 -object iothread,id=iothread1
5497 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
5499 secondary:
5500 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5501 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5502 -chardev socket,id=red0,host=3.3.3.3,port=9003
5503 -chardev socket,id=red1,host=3.3.3.3,port=9004
5504 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5505 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5507 If you want to know the detail of above command line, you can
5508 read the colo-compare git log.
5510 ``-object cryptodev-backend-builtin,id=id[,queues=queues]``
5511 Creates a cryptodev backend which executes crypto operations from
5512 the QEMU cipher APIs. The id parameter is a unique ID that will
5513 be used to reference this cryptodev backend from the
5514 ``virtio-crypto`` device. The queues parameter is optional,
5515 which specify the queue number of cryptodev backend, the default
5516 of queues is 1.
5518 .. parsed-literal::
5520 # |qemu_system| \\
5521 [...] \\
5522 -object cryptodev-backend-builtin,id=cryptodev0 \\
5523 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5524 [...]
5526 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]``
5527 Creates a vhost-user cryptodev backend, backed by a chardev
5528 chardevid. The id parameter is a unique ID that will be used to
5529 reference this cryptodev backend from the ``virtio-crypto``
5530 device. The chardev should be a unix domain socket backed one.
5531 The vhost-user uses a specifically defined protocol to pass
5532 vhost ioctl replacement messages to an application on the other
5533 end of the socket. The queues parameter is optional, which
5534 specify the queue number of cryptodev backend for multiqueue
5535 vhost-user, the default of queues is 1.
5537 .. parsed-literal::
5539 # |qemu_system| \\
5540 [...] \\
5541 -chardev socket,id=chardev0,path=/path/to/socket \\
5542 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\
5543 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5544 [...]
5546 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]``
5548 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]``
5549 Defines a secret to store a password, encryption key, or some
5550 other sensitive data. The sensitive data can either be passed
5551 directly via the data parameter, or indirectly via the file
5552 parameter. Using the data parameter is insecure unless the
5553 sensitive data is encrypted.
5555 The sensitive data can be provided in raw format (the default),
5556 or base64. When encoded as JSON, the raw format only supports
5557 valid UTF-8 characters, so base64 is recommended for sending
5558 binary data. QEMU will convert from which ever format is
5559 provided to the format it needs internally. eg, an RBD password
5560 can be provided in raw format, even though it will be base64
5561 encoded when passed onto the RBD sever.
5563 For added protection, it is possible to encrypt the data
5564 associated with a secret using the AES-256-CBC cipher. Use of
5565 encryption is indicated by providing the keyid and iv
5566 parameters. The keyid parameter provides the ID of a previously
5567 defined secret that contains the AES-256 decryption key. This
5568 key should be 32-bytes long and be base64 encoded. The iv
5569 parameter provides the random initialization vector used for
5570 encryption of this particular secret and should be a base64
5571 encrypted string of the 16-byte IV.
5573 The simplest (insecure) usage is to provide the secret inline
5575 .. parsed-literal::
5577 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw
5579 The simplest secure usage is to provide the secret via a file
5581 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object
5582 secret,id=sec0,file=mypasswd.txt,format=raw
5584 For greater security, AES-256-CBC should be used. To illustrate
5585 usage, consider the openssl command line tool which can encrypt
5586 the data. Note that when encrypting, the plaintext must be
5587 padded to the cipher block size (32 bytes) using the standard
5588 PKCS#5/6 compatible padding algorithm.
5590 First a master key needs to be created in base64 encoding:
5594 # openssl rand -base64 32 > key.b64
5595 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
5597 Each secret to be encrypted needs to have a random
5598 initialization vector generated. These do not need to be kept
5599 secret
5603 # openssl rand -base64 16 > iv.b64
5604 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
5606 The secret to be defined can now be encrypted, in this case
5607 we're telling openssl to base64 encode the result, but it could
5608 be left as raw bytes if desired.
5612 # SECRET=$(printf "letmein" |
5613 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
5615 When launching QEMU, create a master secret pointing to
5616 ``key.b64`` and specify that to be used to decrypt the user
5617 password. Pass the contents of ``iv.b64`` to the second secret
5619 .. parsed-literal::
5621 # |qemu_system| \\
5622 -object secret,id=secmaster0,format=base64,file=key.b64 \\
5623 -object secret,id=sec0,keyid=secmaster0,format=base64,\\
5624 data=$SECRET,iv=$(<iv.b64)
5626 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file,kernel-hashes=on|off]``
5627 Create a Secure Encrypted Virtualization (SEV) guest object,
5628 which can be used to provide the guest memory encryption support
5629 on AMD processors.
5631 When memory encryption is enabled, one of the physical address
5632 bit (aka the C-bit) is utilized to mark if a memory page is
5633 protected. The ``cbitpos`` is used to provide the C-bit
5634 position. The C-bit position is Host family dependent hence user
5635 must provide this value. On EPYC, the value should be 47.
5637 When memory encryption is enabled, we loose certain bits in
5638 physical address space. The ``reduced-phys-bits`` is used to
5639 provide the number of bits we loose in physical address space.
5640 Similar to C-bit, the value is Host family dependent. On EPYC,
5641 a guest will lose a maximum of 1 bit, so the value should be 1.
5643 The ``sev-device`` provides the device file to use for
5644 communicating with the SEV firmware running inside AMD Secure
5645 Processor. The default device is '/dev/sev'. If hardware
5646 supports memory encryption then /dev/sev devices are created by
5647 CCP driver.
5649 The ``policy`` provides the guest policy to be enforced by the
5650 SEV firmware and restrict what configuration and operational
5651 commands can be performed on this guest by the hypervisor. The
5652 policy should be provided by the guest owner and is bound to the
5653 guest and cannot be changed throughout the lifetime of the
5654 guest. The default is 0.
5656 If guest ``policy`` allows sharing the key with another SEV
5657 guest then ``handle`` can be use to provide handle of the guest
5658 from which to share the key.
5660 The ``dh-cert-file`` and ``session-file`` provides the guest
5661 owner's Public Diffie-Hillman key defined in SEV spec. The PDH
5662 and session parameters are used for establishing a cryptographic
5663 session with the guest owner to negotiate keys used for
5664 attestation. The file must be encoded in base64.
5666 The ``kernel-hashes`` adds the hashes of given kernel/initrd/
5667 cmdline to a designated guest firmware page for measured Linux
5668 boot with -kernel. The default is off. (Since 6.2)
5670 e.g to launch a SEV guest
5672 .. parsed-literal::
5674 # |qemu_system_x86| \\
5675 ...... \\
5676 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\
5677 -machine ...,memory-encryption=sev0 \\
5678 .....
5680 ``-object authz-simple,id=id,identity=string``
5681 Create an authorization object that will control access to
5682 network services.
5684 The ``identity`` parameter is identifies the user and its format
5685 depends on the network service that authorization object is
5686 associated with. For authorizing based on TLS x509 certificates,
5687 the identity must be the x509 distinguished name. Note that care
5688 must be taken to escape any commas in the distinguished name.
5690 An example authorization object to validate a x509 distinguished
5691 name would look like:
5693 .. parsed-literal::
5695 # |qemu_system| \\
5696 ... \\
5697 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\
5700 Note the use of quotes due to the x509 distinguished name
5701 containing whitespace, and escaping of ','.
5703 ``-object authz-listfile,id=id,filename=path,refresh=on|off``
5704 Create an authorization object that will control access to
5705 network services.
5707 The ``filename`` parameter is the fully qualified path to a file
5708 containing the access control list rules in JSON format.
5710 An example set of rules that match against SASL usernames might
5711 look like:
5716 "rules": [
5717 { "match": "fred", "policy": "allow", "format": "exact" },
5718 { "match": "bob", "policy": "allow", "format": "exact" },
5719 { "match": "danb", "policy": "deny", "format": "glob" },
5720 { "match": "dan*", "policy": "allow", "format": "exact" },
5722 "policy": "deny"
5725 When checking access the object will iterate over all the rules
5726 and the first rule to match will have its ``policy`` value
5727 returned as the result. If no rules match, then the default
5728 ``policy`` value is returned.
5730 The rules can either be an exact string match, or they can use
5731 the simple UNIX glob pattern matching to allow wildcards to be
5732 used.
5734 If ``refresh`` is set to true the file will be monitored and
5735 automatically reloaded whenever its content changes.
5737 As with the ``authz-simple`` object, the format of the identity
5738 strings being matched depends on the network service, but is
5739 usually a TLS x509 distinguished name, or a SASL username.
5741 An example authorization object to validate a SASL username
5742 would look like:
5744 .. parsed-literal::
5746 # |qemu_system| \\
5747 ... \\
5748 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\
5751 ``-object authz-pam,id=id,service=string``
5752 Create an authorization object that will control access to
5753 network services.
5755 The ``service`` parameter provides the name of a PAM service to
5756 use for authorization. It requires that a file
5757 ``/etc/pam.d/service`` exist to provide the configuration for
5758 the ``account`` subsystem.
5760 An example authorization object to validate a TLS x509
5761 distinguished name would look like:
5763 .. parsed-literal::
5765 # |qemu_system| \\
5766 ... \\
5767 -object authz-pam,id=auth0,service=qemu-vnc \\
5770 There would then be a corresponding config file for PAM at
5771 ``/etc/pam.d/qemu-vnc`` that contains:
5775 account requisite pam_listfile.so item=user sense=allow \
5776 file=/etc/qemu/vnc.allow
5778 Finally the ``/etc/qemu/vnc.allow`` file would contain the list
5779 of x509 distinguished names that are permitted access
5783 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
5785 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch``
5786 Creates a dedicated event loop thread that devices can be
5787 assigned to. This is known as an IOThread. By default device
5788 emulation happens in vCPU threads or the main event loop thread.
5789 This can become a scalability bottleneck. IOThreads allow device
5790 emulation and I/O to run on other host CPUs.
5792 The ``id`` parameter is a unique ID that will be used to
5793 reference this IOThread from ``-device ...,iothread=id``.
5794 Multiple devices can be assigned to an IOThread. Note that not
5795 all devices support an ``iothread`` parameter.
5797 The ``query-iothreads`` QMP command lists IOThreads and reports
5798 their thread IDs so that the user can configure host CPU
5799 pinning/affinity.
5801 IOThreads use an adaptive polling algorithm to reduce event loop
5802 latency. Instead of entering a blocking system call to monitor
5803 file descriptors and then pay the cost of being woken up when an
5804 event occurs, the polling algorithm spins waiting for events for
5805 a short time. The algorithm's default parameters are suitable
5806 for many cases but can be adjusted based on knowledge of the
5807 workload and/or host device latency.
5809 The ``poll-max-ns`` parameter is the maximum number of
5810 nanoseconds to busy wait for events. Polling can be disabled by
5811 setting this value to 0.
5813 The ``poll-grow`` parameter is the multiplier used to increase
5814 the polling time when the algorithm detects it is missing events
5815 due to not polling long enough.
5817 The ``poll-shrink`` parameter is the divisor used to decrease
5818 the polling time when the algorithm detects it is spending too
5819 long polling without encountering events.
5821 The ``aio-max-batch`` parameter is the maximum number of requests
5822 in a batch for the AIO engine, 0 means that the engine will use
5823 its default.
5825 The IOThread parameters can be modified at run-time using the
5826 ``qom-set`` command (where ``iothread1`` is the IOThread's
5827 ``id``):
5831 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
5832 ERST
5835 HXCOMM This is the last statement. Insert new options before this line!
5837 #undef DEF
5838 #undef DEFHEADING
5839 #undef ARCHHEADING