smbios: sanitize type from external type before checking have_fields_bitmap
[qemu.git] / qemu-options.hx
blob1bb02363abd9c3045600e7fbfd74876b8cf6c374
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, hax, 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, hax, 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 provied 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, hax, 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 " split-wx=on|off (enable TCG split w^x mapping)\n"
186 " tb-size=n (TCG translation block cache size)\n"
187 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n"
188 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
189 SRST
190 ``-accel name[,prop=value[,...]]``
191 This is used to enable an accelerator. Depending on the target
192 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By
193 default, tcg is used. If there is more than one accelerator
194 specified, the next one is used if the previous one fails to
195 initialize.
197 ``igd-passthru=on|off``
198 When Xen is in use, this option controls whether Intel
199 integrated graphics devices can be passed through to the guest
200 (default=off)
202 ``kernel-irqchip=on|off|split``
203 Controls KVM in-kernel irqchip support. The default is full
204 acceleration of the interrupt controllers. On x86, split irqchip
205 reduces the kernel attack surface, at a performance cost for
206 non-MSI interrupts. Disabling the in-kernel irqchip completely
207 is not recommended except for debugging purposes.
209 ``kvm-shadow-mem=size``
210 Defines the size of the KVM shadow MMU.
212 ``split-wx=on|off``
213 Controls the use of split w^x mapping for the TCG code generation
214 buffer. Some operating systems require this to be enabled, and in
215 such a case this will default on. On other operating systems, this
216 will default off, but one may enable this for testing or debugging.
218 ``tb-size=n``
219 Controls the size (in MiB) of the TCG translation block cache.
221 ``thread=single|multi``
222 Controls number of TCG threads. When the TCG is multi-threaded
223 there will be one thread per vCPU therefore taking advantage of
224 additional host cores. The default is to enable multi-threading
225 where both the back-end and front-ends support it and no
226 incompatible TCG features have been enabled (e.g.
227 icount/replay).
229 ``dirty-ring-size=n``
230 When the KVM accelerator is used, it controls the size of the per-vCPU
231 dirty page ring buffer (number of entries for each vCPU). It should
232 be a value that is power of two, and it should be 1024 or bigger (but
233 still less than the maximum value that the kernel supports). 4096
234 could be a good initial value if you have no idea which is the best.
235 Set this value to 0 to disable the feature. By default, this feature
236 is disabled (dirty-ring-size=0). When enabled, KVM will instead
237 record dirty pages in a bitmap.
239 ERST
241 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
242 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n"
243 " set the number of initial CPUs to 'n' [default=1]\n"
244 " maxcpus= maximum number of total CPUs, including\n"
245 " offline CPUs for hotplug, etc\n"
246 " sockets= number of sockets on the machine board\n"
247 " dies= number of dies in one socket\n"
248 " clusters= number of clusters in one die\n"
249 " cores= number of cores in one cluster\n"
250 " threads= number of threads in one core\n"
251 "Note: Different machines may have different subsets of the CPU topology\n"
252 " parameters supported, so the actual meaning of the supported parameters\n"
253 " will vary accordingly. For example, for a machine type that supports a\n"
254 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n"
255 " sequentially mean as below:\n"
256 " sockets means the number of sockets on the machine board\n"
257 " cores means the number of cores in one socket\n"
258 " threads means the number of threads in one core\n"
259 " For a particular machine type board, an expected CPU topology hierarchy\n"
260 " can be defined through the supported sub-option. Unsupported parameters\n"
261 " can also be provided in addition to the sub-option, but their values\n"
262 " must be set as 1 in the purpose of correct parsing.\n",
263 QEMU_ARCH_ALL)
264 SRST
265 ``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]``
266 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on
267 the machine type board. On boards supporting CPU hotplug, the optional
268 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be
269 added at runtime. When both parameters are omitted, the maximum number
270 of CPUs will be calculated from the provided topology members and the
271 initial CPU count will match the maximum number. When only one of them
272 is given then the omitted one will be set to its counterpart's value.
273 Both parameters may be specified, but the maximum number of CPUs must
274 be equal to or greater than the initial CPU count. Product of the
275 CPU topology hierarchy must be equal to the maximum number of CPUs.
276 Both parameters are subject to an upper limit that is determined by
277 the specific machine type chosen.
279 To control reporting of CPU topology information, values of the topology
280 parameters can be specified. Machines may only support a subset of the
281 parameters and different machines may have different subsets supported
282 which vary depending on capacity of the corresponding CPU targets. So
283 for a particular machine type board, an expected topology hierarchy can
284 be defined through the supported sub-option. Unsupported parameters can
285 also be provided in addition to the sub-option, but their values must be
286 set as 1 in the purpose of correct parsing.
288 Either the initial CPU count, or at least one of the topology parameters
289 must be specified. The specified parameters must be greater than zero,
290 explicit configuration like "cpus=0" is not allowed. Values for any
291 omitted parameters will be computed from those which are given.
293 For example, the following sub-option defines a CPU topology hierarchy
294 (2 sockets totally on the machine, 2 cores per socket, 2 threads per
295 core) for a machine that only supports sockets/cores/threads.
296 Some members of the option can be omitted but their values will be
297 automatically computed:
301 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8
303 The following sub-option defines a CPU topology hierarchy (2 sockets
304 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads
305 per core) for PC machines which support sockets/dies/cores/threads.
306 Some members of the option can be omitted but their values will be
307 automatically computed:
311 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16
313 The following sub-option defines a CPU topology hierarchy (2 sockets
314 totally on the machine, 2 clusters per socket, 2 cores per cluster,
315 2 threads per core) for ARM virt machines which support sockets/clusters
316 /cores/threads. Some members of the option can be omitted but their values
317 will be automatically computed:
321 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16
323 Historically preference was given to the coarsest topology parameters
324 when computing missing values (ie sockets preferred over cores, which
325 were preferred over threads), however, this behaviour is considered
326 liable to change. Prior to 6.2 the preference was sockets over cores
327 over threads. Since 6.2 the preference is cores over sockets over threads.
329 For example, the following option defines a machine board with 2 sockets
330 of 1 core before 6.2 and 1 socket of 2 cores after 6.2:
334 -smp 2
335 ERST
337 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
338 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
339 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
340 "-numa dist,src=source,dst=destination,val=distance\n"
341 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n"
342 "-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"
343 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n",
344 QEMU_ARCH_ALL)
345 SRST
346 ``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
348 ``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
350 ``-numa dist,src=source,dst=destination,val=distance``
352 ``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]``
354 ``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]``
356 ``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]``
357 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA
358 distance from a source node to a destination node. Set the ACPI
359 Heterogeneous Memory Attributes for the given nodes.
361 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and
362 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a
363 contiguous range of CPU indexes (or a single VCPU if lastcpu is
364 omitted). A non-contiguous set of VCPUs can be represented by
365 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is
366 omitted on all nodes, VCPUs are automatically split between them.
368 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a
369 NUMA node:
373 -numa node,cpus=0-2,cpus=5
375 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option
376 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to
377 assign CPU objects to a node using topology layout properties of
378 CPU. The set of properties is machine specific, and depends on used
379 machine type/'\ ``smp``\ ' options. It could be queried with
380 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ '
381 property specifies node to which CPU object will be assigned, it's
382 required for node to be declared with '\ ``node``\ ' option before
383 it's used with '\ ``cpu``\ ' option.
385 For example:
389 -M pc \
390 -smp 1,sockets=2,maxcpus=2 \
391 -numa node,nodeid=0 -numa node,nodeid=1 \
392 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
394 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported
395 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from
396 a given memory backend device to a node. If '\ ``mem``\ ' and
397 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them.
400 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive.
401 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to
402 use it.
404 '\ ``initiator``\ ' is an additional option that points to an
405 initiator NUMA node that has best performance (the lowest latency or
406 largest bandwidth) to this NUMA node. Note that this option can be
407 set only when the machine property 'hmat' is set to 'on'.
409 Following example creates a machine with 2 NUMA nodes, node 0 has
410 CPU. node 1 has only memory, and its initiator is node 0. Note that
411 because node 0 has CPU, by default the initiator of node 0 is itself
412 and must be itself.
416 -machine hmat=on \
417 -m 2G,slots=2,maxmem=4G \
418 -object memory-backend-ram,size=1G,id=m0 \
419 -object memory-backend-ram,size=1G,id=m1 \
420 -numa node,nodeid=0,memdev=m0 \
421 -numa node,nodeid=1,memdev=m1,initiator=0 \
422 -smp 2,sockets=2,maxcpus=2 \
423 -numa cpu,node-id=0,socket-id=0 \
424 -numa cpu,node-id=0,socket-id=1
426 source and destination are NUMA node IDs. distance is the NUMA
427 distance from source to destination. The distance from a node to
428 itself is always 10. If any pair of nodes is given a distance, then
429 all pairs must be given distances. Although, when distances are only
430 given in one direction for each pair of nodes, then the distances in
431 the opposite directions are assumed to be the same. If, however, an
432 asymmetrical pair of distances is given for even one node pair, then
433 all node pairs must be provided distance values for both directions,
434 even when they are symmetrical. When a node is unreachable from
435 another node, set the pair's distance to 255.
437 Note that the -``numa`` option doesn't allocate any of the specified
438 resources, it just assigns existing resources to NUMA nodes. This
439 means that one still has to use the ``-m``, ``-smp`` options to
440 allocate RAM and VCPUs respectively.
442 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth
443 Information between initiator and target NUMA nodes in ACPI
444 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can
445 create memory requests, usually it has one or more processors.
446 Target NUMA node contains addressable memory.
448 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is
449 the memory hierarchy of the target NUMA node: if hierarchy is
450 'memory', the structure represents the memory performance; if
451 hierarchy is 'first-level\|second-level\|third-level', this
452 structure represents aggregated performance of memory side caches
453 for each domain. type of 'data-type' is type of data represented by
454 this structure instance: if 'hierarchy' is 'memory', 'data-type' is
455 'access\|read\|write' latency or 'access\|read\|write' bandwidth of
456 the target memory; if 'hierarchy' is
457 'first-level\|second-level\|third-level', 'data-type' is
458 'access\|read\|write' hit latency or 'access\|read\|write' hit
459 bandwidth of the target memory side cache.
461 lat is latency value in nanoseconds. bw is bandwidth value, the
462 possible value and units are NUM[M\|G\|T], mean that the bandwidth
463 value are NUM byte per second (or MB/s, GB/s or TB/s depending on
464 used suffix). Note that if latency or bandwidth value is 0, means
465 the corresponding latency or bandwidth information is not provided.
467 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory
468 belongs. size is the size of memory side cache in bytes. level is
469 the cache level described in this structure, note that the cache
470 level 0 should not be used with '\ ``hmat-cache``\ ' option.
471 associativity is the cache associativity, the possible value is
472 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy
473 is the write policy. line is the cache Line size in bytes.
475 For example, the following options describe 2 NUMA nodes. Node 0 has
476 2 cpus and a ram, node 1 has only a ram. The processors in node 0
477 access memory in node 0 with access-latency 5 nanoseconds,
478 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access
479 memory in NUMA node 1 with access-latency 10 nanoseconds,
480 access-bandwidth is 100 MB/s. And for memory side cache information,
481 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB,
482 policy is write-back, the cache Line size is 8 bytes:
486 -machine hmat=on \
487 -m 2G \
488 -object memory-backend-ram,size=1G,id=m0 \
489 -object memory-backend-ram,size=1G,id=m1 \
490 -smp 2,sockets=2,maxcpus=2 \
491 -numa node,nodeid=0,memdev=m0 \
492 -numa node,nodeid=1,memdev=m1,initiator=0 \
493 -numa cpu,node-id=0,socket-id=0 \
494 -numa cpu,node-id=0,socket-id=1 \
495 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \
496 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \
497 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \
498 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \
499 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \
500 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8
501 ERST
503 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
504 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
505 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
506 SRST
507 ``-add-fd fd=fd,set=set[,opaque=opaque]``
508 Add a file descriptor to an fd set. Valid options are:
510 ``fd=fd``
511 This option defines the file descriptor of which a duplicate is
512 added to fd set. The file descriptor cannot be stdin, stdout, or
513 stderr.
515 ``set=set``
516 This option defines the ID of the fd set to add the file
517 descriptor to.
519 ``opaque=opaque``
520 This option defines a free-form string that can be used to
521 describe fd.
523 You can open an image using pre-opened file descriptors from an fd
524 set:
526 .. parsed-literal::
528 |qemu_system| \\
529 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
530 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
531 -drive file=/dev/fdset/2,index=0,media=disk
532 ERST
534 DEF("set", HAS_ARG, QEMU_OPTION_set,
535 "-set group.id.arg=value\n"
536 " set <arg> parameter for item <id> of type <group>\n"
537 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
538 SRST
539 ``-set group.id.arg=value``
540 Set parameter arg for item id of type group
541 ERST
543 DEF("global", HAS_ARG, QEMU_OPTION_global,
544 "-global driver.property=value\n"
545 "-global driver=driver,property=property,value=value\n"
546 " set a global default for a driver property\n",
547 QEMU_ARCH_ALL)
548 SRST
549 ``-global driver.prop=value``
551 ``-global driver=driver,property=property,value=value``
552 Set default value of driver's property prop to value, e.g.:
554 .. parsed-literal::
556 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img
558 In particular, you can use this to set driver properties for devices
559 which are created automatically by the machine model. To create a
560 device which is not created automatically and set properties on it,
561 use -``device``.
563 -global driver.prop=value is shorthand for -global
564 driver=driver,property=prop,value=value. The longhand syntax works
565 even when driver contains a dot.
566 ERST
568 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
569 "-boot [order=drives][,once=drives][,menu=on|off]\n"
570 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
571 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
572 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
573 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
574 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
575 QEMU_ARCH_ALL)
576 SRST
577 ``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]``
578 Specify boot order drives as a string of drive letters. Valid drive
579 letters depend on the target architecture. The x86 PC uses: a, b
580 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p
581 (Etherboot from network adapter 1-4), hard disk boot is the default.
582 To apply a particular boot order only on the first startup, specify
583 it via ``once``. Note that the ``order`` or ``once`` parameter
584 should not be used together with the ``bootindex`` property of
585 devices, since the firmware implementations normally do not support
586 both at the same time.
588 Interactive boot menus/prompts can be enabled via ``menu=on`` as far
589 as firmware/BIOS supports them. The default is non-interactive boot.
591 A splash picture could be passed to bios, enabling user to show it
592 as logo, when option splash=sp\_name is given and menu=on, If
593 firmware/BIOS supports them. Currently Seabios for X86 system
594 support it. limitation: The splash file could be a jpeg file or a
595 BMP file in 24 BPP format(true color). The resolution should be
596 supported by the SVGA mode, so the recommended is 320x240, 640x480,
597 800x640.
599 A timeout could be passed to bios, guest will pause for rb\_timeout
600 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will
601 not reboot, qemu passes '-1' to bios by default. Currently Seabios
602 for X86 system support it.
604 Do strict boot via ``strict=on`` as far as firmware/BIOS supports
605 it. This only effects when boot priority is changed by bootindex
606 options. The default is non-strict boot.
608 .. parsed-literal::
610 # try to boot from network first, then from hard disk
611 |qemu_system_x86| -boot order=nc
612 # boot from CD-ROM first, switch back to default order after reboot
613 |qemu_system_x86| -boot once=d
614 # boot with a splash picture for 5 seconds.
615 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000
617 Note: The legacy format '-boot drives' is still supported but its
618 use is discouraged as it may be removed from future versions.
619 ERST
621 DEF("m", HAS_ARG, QEMU_OPTION_m,
622 "-m [size=]megs[,slots=n,maxmem=size]\n"
623 " configure guest RAM\n"
624 " size: initial amount of guest memory\n"
625 " slots: number of hotplug slots (default: none)\n"
626 " maxmem: maximum amount of guest memory (default: none)\n"
627 "NOTE: Some architectures might enforce a specific granularity\n",
628 QEMU_ARCH_ALL)
629 SRST
630 ``-m [size=]megs[,slots=n,maxmem=size]``
631 Sets guest startup RAM size to megs megabytes. Default is 128 MiB.
632 Optionally, a suffix of "M" or "G" can be used to signify a value in
633 megabytes or gigabytes respectively. Optional pair slots, maxmem
634 could be used to set amount of hotpluggable memory slots and maximum
635 amount of memory. Note that maxmem must be aligned to the page size.
637 For example, the following command-line sets the guest startup RAM
638 size to 1GB, creates 3 slots to hotplug additional memory and sets
639 the maximum memory the guest can reach to 4GB:
641 .. parsed-literal::
643 |qemu_system| -m 1G,slots=3,maxmem=4G
645 If slots and maxmem are not specified, memory hotplug won't be
646 enabled and the guest startup RAM will never increase.
647 ERST
649 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
650 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
651 SRST
652 ``-mem-path path``
653 Allocate guest RAM from a temporarily created file in path.
654 ERST
656 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
657 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
658 QEMU_ARCH_ALL)
659 SRST
660 ``-mem-prealloc``
661 Preallocate memory when using -mem-path.
662 ERST
664 DEF("k", HAS_ARG, QEMU_OPTION_k,
665 "-k language use keyboard layout (for example 'fr' for French)\n",
666 QEMU_ARCH_ALL)
667 SRST
668 ``-k language``
669 Use keyboard layout language (for example ``fr`` for French). This
670 option is only needed where it is not easy to get raw PC keycodes
671 (e.g. on Macs, with some X11 servers or with a VNC or curses
672 display). You don't normally need to use it on PC/Linux or
673 PC/Windows hosts.
675 The available layouts are:
679 ar de-ch es fo fr-ca hu ja mk no pt-br sv
680 da en-gb et fr fr-ch is lt nl pl ru th
681 de en-us fi fr-be hr it lv nl-be pt sl tr
683 The default is ``en-us``.
684 ERST
687 HXCOMM Deprecated by -audiodev
688 DEF("audio-help", 0, QEMU_OPTION_audio_help,
689 "-audio-help show -audiodev equivalent of the currently specified audio settings\n",
690 QEMU_ARCH_ALL)
691 SRST
692 ``-audio-help``
693 Will show the -audiodev equivalent of the currently specified
694 (deprecated) environment variables.
695 ERST
697 DEF("audio", HAS_ARG, QEMU_OPTION_audio,
698 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n"
699 " specifies the audio backend and device to use;\n"
700 " apart from 'model', options are the same as for -audiodev.\n"
701 " use '-audio model=help' to show possible devices.\n",
702 QEMU_ARCH_ALL)
703 SRST
704 ``-audio [driver=]driver,model=value[,prop[=value][,...]]``
705 This option is a shortcut for configuring both the guest audio
706 hardware and the host audio backend in one go.
707 The host backend options are the same as with the corresponding
708 ``-audiodev`` options below. The guest hardware model can be set with
709 ``model=modelname``. Use ``model=help`` to list the available device
710 types.
712 The following two example do exactly the same, to show how ``-audio``
713 can be used to shorten the command line length:
715 .. parsed-literal::
717 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa
718 |qemu_system| -audio pa,model=sb16
719 ERST
721 DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
722 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
723 " specifies the audio backend to use\n"
724 " id= identifier of the backend\n"
725 " timer-period= timer period in microseconds\n"
726 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n"
727 " in|out.fixed-settings= use fixed settings for host audio\n"
728 " in|out.frequency= frequency to use with fixed settings\n"
729 " in|out.channels= number of channels to use with fixed settings\n"
730 " in|out.format= sample format to use with fixed settings\n"
731 " valid values: s8, s16, s32, u8, u16, u32, f32\n"
732 " in|out.voices= number of voices to use\n"
733 " in|out.buffer-length= length of buffer in microseconds\n"
734 "-audiodev none,id=id,[,prop[=value][,...]]\n"
735 " dummy driver that discards all output\n"
736 #ifdef CONFIG_AUDIO_ALSA
737 "-audiodev alsa,id=id[,prop[=value][,...]]\n"
738 " in|out.dev= name of the audio device to use\n"
739 " in|out.period-length= length of period in microseconds\n"
740 " in|out.try-poll= attempt to use poll mode\n"
741 " threshold= threshold (in microseconds) when playback starts\n"
742 #endif
743 #ifdef CONFIG_AUDIO_COREAUDIO
744 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
745 " in|out.buffer-count= number of buffers\n"
746 #endif
747 #ifdef CONFIG_AUDIO_DSOUND
748 "-audiodev dsound,id=id[,prop[=value][,...]]\n"
749 " latency= add extra latency to playback in microseconds\n"
750 #endif
751 #ifdef CONFIG_AUDIO_OSS
752 "-audiodev oss,id=id[,prop[=value][,...]]\n"
753 " in|out.dev= path of the audio device to use\n"
754 " in|out.buffer-count= number of buffers\n"
755 " in|out.try-poll= attempt to use poll mode\n"
756 " try-mmap= try using memory mapped access\n"
757 " exclusive= open device in exclusive mode\n"
758 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
759 #endif
760 #ifdef CONFIG_AUDIO_PA
761 "-audiodev pa,id=id[,prop[=value][,...]]\n"
762 " server= PulseAudio server address\n"
763 " in|out.name= source/sink device name\n"
764 " in|out.latency= desired latency in microseconds\n"
765 #endif
766 #ifdef CONFIG_AUDIO_SDL
767 "-audiodev sdl,id=id[,prop[=value][,...]]\n"
768 " in|out.buffer-count= number of buffers\n"
769 #endif
770 #ifdef CONFIG_SPICE
771 "-audiodev spice,id=id[,prop[=value][,...]]\n"
772 #endif
773 #ifdef CONFIG_DBUS_DISPLAY
774 "-audiodev dbus,id=id[,prop[=value][,...]]\n"
775 #endif
776 "-audiodev wav,id=id[,prop[=value][,...]]\n"
777 " path= path of wav file to record\n",
778 QEMU_ARCH_ALL)
779 SRST
780 ``-audiodev [driver=]driver,id=id[,prop[=value][,...]]``
781 Adds a new audio backend driver identified by id. There are global
782 and driver specific properties. Some values can be set differently
783 for input and output, they're marked with ``in|out.``. You can set
784 the input's property with ``in.prop`` and the output's property with
785 ``out.prop``. For example:
789 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
790 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
792 NOTE: parameter validation is known to be incomplete, in many cases
793 specifying an invalid option causes QEMU to print an error message
794 and continue emulation without sound.
796 Valid global options are:
798 ``id=identifier``
799 Identifies the audio backend.
801 ``timer-period=period``
802 Sets the timer period used by the audio subsystem in
803 microseconds. Default is 10000 (10 ms).
805 ``in|out.mixing-engine=on|off``
806 Use QEMU's mixing engine to mix all streams inside QEMU and
807 convert audio formats when not supported by the backend. When
808 off, fixed-settings must be off too. Note that disabling this
809 option means that the selected backend must support multiple
810 streams and the audio formats used by the virtual cards,
811 otherwise you'll get no sound. It's not recommended to disable
812 this option unless you want to use 5.1 or 7.1 audio, as mixing
813 engine only supports mono and stereo audio. Default is on.
815 ``in|out.fixed-settings=on|off``
816 Use fixed settings for host audio. When off, it will change
817 based on how the guest opens the sound card. In this case you
818 must not specify frequency, channels or format. Default is on.
820 ``in|out.frequency=frequency``
821 Specify the frequency to use when using fixed-settings. Default
822 is 44100Hz.
824 ``in|out.channels=channels``
825 Specify the number of channels to use when using fixed-settings.
826 Default is 2 (stereo).
828 ``in|out.format=format``
829 Specify the sample format to use when using fixed-settings.
830 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``,
831 ``u32``, ``f32``. Default is ``s16``.
833 ``in|out.voices=voices``
834 Specify the number of voices to use. Default is 1.
836 ``in|out.buffer-length=usecs``
837 Sets the size of the buffer in microseconds.
839 ``-audiodev none,id=id[,prop[=value][,...]]``
840 Creates a dummy backend that discards all outputs. This backend has
841 no backend specific properties.
843 ``-audiodev alsa,id=id[,prop[=value][,...]]``
844 Creates backend using the ALSA. This backend is only available on
845 Linux.
847 ALSA specific options are:
849 ``in|out.dev=device``
850 Specify the ALSA device to use for input and/or output. Default
851 is ``default``.
853 ``in|out.period-length=usecs``
854 Sets the period length in microseconds.
856 ``in|out.try-poll=on|off``
857 Attempt to use poll mode with the device. Default is on.
859 ``threshold=threshold``
860 Threshold (in microseconds) when playback starts. Default is 0.
862 ``-audiodev coreaudio,id=id[,prop[=value][,...]]``
863 Creates a backend using Apple's Core Audio. This backend is only
864 available on Mac OS and only supports playback.
866 Core Audio specific options are:
868 ``in|out.buffer-count=count``
869 Sets the count of the buffers.
871 ``-audiodev dsound,id=id[,prop[=value][,...]]``
872 Creates a backend using Microsoft's DirectSound. This backend is
873 only available on Windows and only supports playback.
875 DirectSound specific options are:
877 ``latency=usecs``
878 Add extra usecs microseconds latency to playback. Default is
879 10000 (10 ms).
881 ``-audiodev oss,id=id[,prop[=value][,...]]``
882 Creates a backend using OSS. This backend is available on most
883 Unix-like systems.
885 OSS specific options are:
887 ``in|out.dev=device``
888 Specify the file name of the OSS device to use. Default is
889 ``/dev/dsp``.
891 ``in|out.buffer-count=count``
892 Sets the count of the buffers.
894 ``in|out.try-poll=on|of``
895 Attempt to use poll mode with the device. Default is on.
897 ``try-mmap=on|off``
898 Try using memory mapped device access. Default is off.
900 ``exclusive=on|off``
901 Open the device in exclusive mode (vmix won't work in this
902 case). Default is off.
904 ``dsp-policy=policy``
905 Sets the timing policy (between 0 and 10, where smaller number
906 means smaller latency but higher CPU usage). Use -1 to use
907 buffer sizes specified by ``buffer`` and ``buffer-count``. This
908 option is ignored if you do not have OSS 4. Default is 5.
910 ``-audiodev pa,id=id[,prop[=value][,...]]``
911 Creates a backend using PulseAudio. This backend is available on
912 most systems.
914 PulseAudio specific options are:
916 ``server=server``
917 Sets the PulseAudio server to connect to.
919 ``in|out.name=sink``
920 Use the specified source/sink for recording/playback.
922 ``in|out.latency=usecs``
923 Desired latency in microseconds. The PulseAudio server will try
924 to honor this value but actual latencies may be lower or higher.
926 ``-audiodev sdl,id=id[,prop[=value][,...]]``
927 Creates a backend using SDL. This backend is available on most
928 systems, but you should use your platform's native backend if
929 possible.
931 SDL specific options are:
933 ``in|out.buffer-count=count``
934 Sets the count of the buffers.
936 ``-audiodev spice,id=id[,prop[=value][,...]]``
937 Creates a backend that sends audio through SPICE. This backend
938 requires ``-spice`` and automatically selected in that case, so
939 usually you can ignore this option. This backend has no backend
940 specific properties.
942 ``-audiodev wav,id=id[,prop[=value][,...]]``
943 Creates a backend that writes audio to a WAV file.
945 Backend specific options are:
947 ``path=path``
948 Write recorded audio into the specified file. Default is
949 ``qemu.wav``.
950 ERST
952 DEF("device", HAS_ARG, QEMU_OPTION_device,
953 "-device driver[,prop[=value][,...]]\n"
954 " add device (based on driver)\n"
955 " prop=value,... sets driver properties\n"
956 " use '-device help' to print all possible drivers\n"
957 " use '-device driver,help' to print all possible properties\n",
958 QEMU_ARCH_ALL)
959 SRST
960 ``-device driver[,prop[=value][,...]]``
961 Add device driver. prop=value sets driver properties. Valid
962 properties depend on the driver. To get help on possible drivers and
963 properties, use ``-device help`` and ``-device driver,help``.
965 Some drivers are:
967 ``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]``
968 Add an IPMI BMC. This is a simulation of a hardware management
969 interface processor that normally sits on a system. It provides a
970 watchdog and the ability to reset and power control the system. You
971 need to connect this to an IPMI interface to make it useful
973 The IPMI slave address to use for the BMC. The default is 0x20. This
974 address is the BMC's address on the I2C network of management
975 controllers. If you don't know what this means, it is safe to ignore
978 ``id=id``
979 The BMC id for interfaces to use this device.
981 ``slave_addr=val``
982 Define slave address to use for the BMC. The default is 0x20.
984 ``sdrfile=file``
985 file containing raw Sensor Data Records (SDR) data. The default
986 is none.
988 ``fruareasize=val``
989 size of a Field Replaceable Unit (FRU) area. The default is
990 1024.
992 ``frudatafile=file``
993 file containing raw Field Replaceable Unit (FRU) inventory data.
994 The default is none.
996 ``guid=uuid``
997 value for the GUID for the BMC, in standard UUID format. If this
998 is set, get "Get GUID" command to the BMC will return it.
999 Otherwise "Get GUID" will return an error.
1001 ``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]``
1002 Add a connection to an external IPMI BMC simulator. Instead of
1003 locally emulating the BMC like the above item, instead connect to an
1004 external entity that provides the IPMI services.
1006 A connection is made to an external BMC simulator. If you do this,
1007 it is strongly recommended that you use the "reconnect=" chardev
1008 option to reconnect to the simulator if the connection is lost. Note
1009 that if this is not used carefully, it can be a security issue, as
1010 the interface has the ability to send resets, NMIs, and power off
1011 the VM. It's best if QEMU makes a connection to an external
1012 simulator running on a secure port on localhost, so neither the
1013 simulator nor QEMU is exposed to any outside network.
1015 See the "lanserv/README.vm" file in the OpenIPMI library for more
1016 details on the external interface.
1018 ``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]``
1019 Add a KCS IPMI interafce on the ISA bus. This also adds a
1020 corresponding ACPI and SMBIOS entries, if appropriate.
1022 ``bmc=id``
1023 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern
1024 above.
1026 ``ioport=val``
1027 Define the I/O address of the interface. The default is 0xca0
1028 for KCS.
1030 ``irq=val``
1031 Define the interrupt to use. The default is 5. To disable
1032 interrupts, set this to 0.
1034 ``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]``
1035 Like the KCS interface, but defines a BT interface. The default port
1036 is 0xe4 and the default interrupt is 5.
1038 ``-device pci-ipmi-kcs,bmc=id``
1039 Add a KCS IPMI interafce on the PCI bus.
1041 ``bmc=id``
1042 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
1044 ``-device pci-ipmi-bt,bmc=id``
1045 Like the KCS interface, but defines a BT interface on the PCI bus.
1047 ``-device intel-iommu[,option=...]``
1048 This is only supported by ``-machine q35``, which will enable Intel VT-d
1049 emulation within the guest. It supports below options:
1051 ``intremap=on|off`` (default: auto)
1052 This enables interrupt remapping feature. It's required to enable
1053 complete x2apic. Currently it only supports kvm kernel-irqchip modes
1054 ``off`` or ``split``, while full kernel-irqchip is not yet supported.
1055 The default value is "auto", which will be decided by the mode of
1056 kernel-irqchip.
1058 ``caching-mode=on|off`` (default: off)
1059 This enables caching mode for the VT-d emulated device. When
1060 caching-mode is enabled, each guest DMA buffer mapping will generate an
1061 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in
1062 a synchronous way. It is required for ``-device vfio-pci`` to work
1063 with the VT-d device, because host assigned devices requires to setup
1064 the DMA mapping on the host before guest DMA starts.
1066 ``device-iotlb=on|off`` (default: off)
1067 This enables device-iotlb capability for the emulated VT-d device. So
1068 far virtio/vhost should be the only real user for this parameter,
1069 paired with ats=on configured for the device.
1071 ``aw-bits=39|48`` (default: 39)
1072 This decides the address width of IOVA address space. The address
1073 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for
1074 4-level IOMMU page tables.
1076 Please also refer to the wiki page for general scenarios of VT-d
1077 emulation in QEMU: https://wiki.qemu.org/Features/VT-d.
1079 ERST
1081 DEF("name", HAS_ARG, QEMU_OPTION_name,
1082 "-name string1[,process=string2][,debug-threads=on|off]\n"
1083 " set the name of the guest\n"
1084 " string1 sets the window title and string2 the process name\n"
1085 " When debug-threads is enabled, individual threads are given a separate name\n"
1086 " NOTE: The thread names are for debugging and not a stable API.\n",
1087 QEMU_ARCH_ALL)
1088 SRST
1089 ``-name name``
1090 Sets the name of the guest. This name will be displayed in the SDL
1091 window caption. The name will also be used for the VNC server. Also
1092 optionally set the top visible process name in Linux. Naming of
1093 individual threads can also be enabled on Linux to aid debugging.
1094 ERST
1096 DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
1097 "-uuid %08x-%04x-%04x-%04x-%012x\n"
1098 " specify machine UUID\n", QEMU_ARCH_ALL)
1099 SRST
1100 ``-uuid uuid``
1101 Set system UUID.
1102 ERST
1104 DEFHEADING()
1106 DEFHEADING(Block device options:)
1108 SRST
1109 The QEMU block device handling options have a long history and
1110 have gone through several iterations as the feature set and complexity
1111 of the block layer have grown. Many online guides to QEMU often
1112 reference older and deprecated options, which can lead to confusion.
1114 The recommended modern way to describe disks is to use a combination of
1115 ``-device`` to specify the hardware device and ``-blockdev`` to
1116 describe the backend. The device defines what the guest sees and the
1117 backend describes how QEMU handles the data.
1119 ERST
1121 DEF("fda", HAS_ARG, QEMU_OPTION_fda,
1122 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
1123 DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
1124 SRST
1125 ``-fda file``
1127 ``-fdb file``
1128 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in
1129 the System Emulation Users Guide).
1130 ERST
1132 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
1133 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
1134 DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
1135 DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
1136 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
1137 DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
1138 SRST
1139 ``-hda file``
1141 ``-hdb file``
1143 ``-hdc file``
1145 ``-hdd file``
1146 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images`
1147 chapter in the System Emulation Users Guide).
1148 ERST
1150 DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
1151 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
1152 QEMU_ARCH_ALL)
1153 SRST
1154 ``-cdrom file``
1155 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at
1156 the same time). You can use the host CD-ROM by using ``/dev/cdrom``
1157 as filename.
1158 ERST
1160 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
1161 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
1162 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
1163 " [,read-only=on|off][,auto-read-only=on|off]\n"
1164 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
1165 " [,driver specific parameters...]\n"
1166 " configure a block backend\n", QEMU_ARCH_ALL)
1167 SRST
1168 ``-blockdev option[,option[,option[,...]]]``
1169 Define a new block driver node. Some of the options apply to all
1170 block drivers, other options are only accepted for a specific block
1171 driver. See below for a list of generic options and options for the
1172 most common block drivers.
1174 Options that expect a reference to another node (e.g. ``file``) can
1175 be given in two ways. Either you specify the node name of an already
1176 existing node (file=node-name), or you define a new node inline,
1177 adding options for the referenced node after a dot
1178 (file.filename=path,file.aio=native).
1180 A block driver node created with ``-blockdev`` can be used for a
1181 guest device by specifying its node name for the ``drive`` property
1182 in a ``-device`` argument that defines a block device.
1184 ``Valid options for any block driver node:``
1185 ``driver``
1186 Specifies the block driver to use for the given node.
1188 ``node-name``
1189 This defines the name of the block driver node by which it
1190 will be referenced later. The name must be unique, i.e. it
1191 must not match the name of a different block driver node, or
1192 (if you use ``-drive`` as well) the ID of a drive.
1194 If no node name is specified, it is automatically generated.
1195 The generated node name is not intended to be predictable
1196 and changes between QEMU invocations. For the top level, an
1197 explicit node name must be specified.
1199 ``read-only``
1200 Open the node read-only. Guest write attempts will fail.
1202 Note that some block drivers support only read-only access,
1203 either generally or in certain configurations. In this case,
1204 the default value ``read-only=off`` does not work and the
1205 option must be specified explicitly.
1207 ``auto-read-only``
1208 If ``auto-read-only=on`` is set, QEMU may fall back to
1209 read-only usage even when ``read-only=off`` is requested, or
1210 even switch between modes as needed, e.g. depending on
1211 whether the image file is writable or whether a writing user
1212 is attached to the node.
1214 ``force-share``
1215 Override the image locking system of QEMU by forcing the
1216 node to utilize weaker shared access for permissions where
1217 it would normally request exclusive access. When there is
1218 the potential for multiple instances to have the same file
1219 open (whether this invocation of QEMU is the first or the
1220 second instance), both instances must permit shared access
1221 for the second instance to succeed at opening the file.
1223 Enabling ``force-share=on`` requires ``read-only=on``.
1225 ``cache.direct``
1226 The host page cache can be avoided with ``cache.direct=on``.
1227 This will attempt to do disk IO directly to the guest's
1228 memory. QEMU may still perform an internal copy of the data.
1230 ``cache.no-flush``
1231 In case you don't care about data integrity over host
1232 failures, you can use ``cache.no-flush=on``. This option
1233 tells QEMU that it never needs to write any data to the disk
1234 but can instead keep things in cache. If anything goes
1235 wrong, like your host losing power, the disk storage getting
1236 disconnected accidentally, etc. your image will most
1237 probably be rendered unusable.
1239 ``discard=discard``
1240 discard is one of "ignore" (or "off") or "unmap" (or "on")
1241 and controls whether ``discard`` (also known as ``trim`` or
1242 ``unmap``) requests are ignored or passed to the filesystem.
1243 Some machine types may not support discard requests.
1245 ``detect-zeroes=detect-zeroes``
1246 detect-zeroes is "off", "on" or "unmap" and enables the
1247 automatic conversion of plain zero writes by the OS to
1248 driver specific optimized zero write commands. You may even
1249 choose "unmap" if discard is set to "unmap" to allow a zero
1250 write to be converted to an ``unmap`` operation.
1252 ``Driver-specific options for file``
1253 This is the protocol-level block driver for accessing regular
1254 files.
1256 ``filename``
1257 The path to the image file in the local filesystem
1259 ``aio``
1260 Specifies the AIO backend (threads/native/io_uring,
1261 default: threads)
1263 ``locking``
1264 Specifies whether the image file is protected with Linux OFD
1265 / POSIX locks. The default is to use the Linux Open File
1266 Descriptor API if available, otherwise no lock is applied.
1267 (auto/on/off, default: auto)
1269 Example:
1273 -blockdev driver=file,node-name=disk,filename=disk.img
1275 ``Driver-specific options for raw``
1276 This is the image format block driver for raw images. It is
1277 usually stacked on top of a protocol level block driver such as
1278 ``file``.
1280 ``file``
1281 Reference to or definition of the data source block driver
1282 node (e.g. a ``file`` driver node)
1284 Example 1:
1288 -blockdev driver=file,node-name=disk_file,filename=disk.img
1289 -blockdev driver=raw,node-name=disk,file=disk_file
1291 Example 2:
1295 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1297 ``Driver-specific options for qcow2``
1298 This is the image format block driver for qcow2 images. It is
1299 usually stacked on top of a protocol level block driver such as
1300 ``file``.
1302 ``file``
1303 Reference to or definition of the data source block driver
1304 node (e.g. a ``file`` driver node)
1306 ``backing``
1307 Reference to or definition of the backing file block device
1308 (default is taken from the image file). It is allowed to
1309 pass ``null`` here in order to disable the default backing
1310 file.
1312 ``lazy-refcounts``
1313 Whether to enable the lazy refcounts feature (on/off;
1314 default is taken from the image file)
1316 ``cache-size``
1317 The maximum total size of the L2 table and refcount block
1318 caches in bytes (default: the sum of l2-cache-size and
1319 refcount-cache-size)
1321 ``l2-cache-size``
1322 The maximum size of the L2 table cache in bytes (default: if
1323 cache-size is not specified - 32M on Linux platforms, and 8M
1324 on non-Linux platforms; otherwise, as large as possible
1325 within the cache-size, while permitting the requested or the
1326 minimal refcount cache size)
1328 ``refcount-cache-size``
1329 The maximum size of the refcount block cache in bytes
1330 (default: 4 times the cluster size; or if cache-size is
1331 specified, the part of it which is not used for the L2
1332 cache)
1334 ``cache-clean-interval``
1335 Clean unused entries in the L2 and refcount caches. The
1336 interval is in seconds. The default value is 600 on
1337 supporting platforms, and 0 on other platforms. Setting it
1338 to 0 disables this feature.
1340 ``pass-discard-request``
1341 Whether discard requests to the qcow2 device should be
1342 forwarded to the data source (on/off; default: on if
1343 discard=unmap is specified, off otherwise)
1345 ``pass-discard-snapshot``
1346 Whether discard requests for the data source should be
1347 issued when a snapshot operation (e.g. deleting a snapshot)
1348 frees clusters in the qcow2 file (on/off; default: on)
1350 ``pass-discard-other``
1351 Whether discard requests for the data source should be
1352 issued on other occasions where a cluster gets freed
1353 (on/off; default: off)
1355 ``overlap-check``
1356 Which overlap checks to perform for writes to the image
1357 (none/constant/cached/all; default: cached). For details or
1358 finer granularity control refer to the QAPI documentation of
1359 ``blockdev-add``.
1361 Example 1:
1365 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1366 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1368 Example 2:
1372 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1374 ``Driver-specific options for other drivers``
1375 Please refer to the QAPI documentation of the ``blockdev-add``
1376 QMP command.
1377 ERST
1379 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1380 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1381 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1382 " [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1383 " [,werror=ignore|stop|report|enospc][,id=name]\n"
1384 " [,aio=threads|native|io_uring]\n"
1385 " [,readonly=on|off][,copy-on-read=on|off]\n"
1386 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1387 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1388 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1389 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1390 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1391 " [[,iops_size=is]]\n"
1392 " [[,group=g]]\n"
1393 " use 'file' as a drive image\n", QEMU_ARCH_ALL)
1394 SRST
1395 ``-drive option[,option[,option[,...]]]``
1396 Define a new drive. This includes creating a block driver node (the
1397 backend) as well as a guest device, and is mostly a shortcut for
1398 defining the corresponding ``-blockdev`` and ``-device`` options.
1400 ``-drive`` accepts all options that are accepted by ``-blockdev``.
1401 In addition, it knows the following options:
1403 ``file=file``
1404 This option defines which disk image (see the :ref:`disk images`
1405 chapter in the System Emulation Users Guide) to use with this drive.
1406 If the filename contains comma, you must double it (for instance,
1407 "file=my,,file" to use file "my,file").
1409 Special files such as iSCSI devices can be specified using
1410 protocol specific URLs. See the section for "Device URL Syntax"
1411 for more information.
1413 ``if=interface``
1414 This option defines on which type on interface the drive is
1415 connected. Available types are: ide, scsi, sd, mtd, floppy,
1416 pflash, virtio, none.
1418 ``bus=bus,unit=unit``
1419 These options define where is connected the drive by defining
1420 the bus number and the unit id.
1422 ``index=index``
1423 This option defines where the drive is connected by using an
1424 index in the list of available connectors of a given interface
1425 type.
1427 ``media=media``
1428 This option defines the type of the media: disk or cdrom.
1430 ``snapshot=snapshot``
1431 snapshot is "on" or "off" and controls snapshot mode for the
1432 given drive (see ``-snapshot``).
1434 ``cache=cache``
1435 cache is "none", "writeback", "unsafe", "directsync" or
1436 "writethrough" and controls how the host cache is used to access
1437 block data. This is a shortcut that sets the ``cache.direct``
1438 and ``cache.no-flush`` options (as in ``-blockdev``), and
1439 additionally ``cache.writeback``, which provides a default for
1440 the ``write-cache`` option of block guest devices (as in
1441 ``-device``). The modes correspond to the following settings:
1443 ============= =============== ============ ==============
1444 \ cache.writeback cache.direct cache.no-flush
1445 ============= =============== ============ ==============
1446 writeback on off off
1447 none on on off
1448 writethrough off off off
1449 directsync off on off
1450 unsafe on off on
1451 ============= =============== ============ ==============
1453 The default mode is ``cache=writeback``.
1455 ``aio=aio``
1456 aio is "threads", "native", or "io_uring" and selects between pthread
1457 based disk I/O, native Linux AIO, or Linux io_uring API.
1459 ``format=format``
1460 Specify which disk format will be used rather than detecting the
1461 format. Can be used to specify format=raw to avoid interpreting
1462 an untrusted format header.
1464 ``werror=action,rerror=action``
1465 Specify which action to take on write and read errors. Valid
1466 actions are: "ignore" (ignore the error and try to continue),
1467 "stop" (pause QEMU), "report" (report the error to the guest),
1468 "enospc" (pause QEMU only if the host disk is full; report the
1469 error to the guest otherwise). The default setting is
1470 ``werror=enospc`` and ``rerror=report``.
1472 ``copy-on-read=copy-on-read``
1473 copy-on-read is "on" or "off" and enables whether to copy read
1474 backing file sectors into the image file.
1476 ``bps=b,bps_rd=r,bps_wr=w``
1477 Specify bandwidth throttling limits in bytes per second, either
1478 for all request types or for reads or writes only. Small values
1479 can lead to timeouts or hangs inside the guest. A safe minimum
1480 for disks is 2 MB/s.
1482 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm``
1483 Specify bursts in bytes per second, either for all request types
1484 or for reads or writes only. Bursts allow the guest I/O to spike
1485 above the limit temporarily.
1487 ``iops=i,iops_rd=r,iops_wr=w``
1488 Specify request rate limits in requests per second, either for
1489 all request types or for reads or writes only.
1491 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm``
1492 Specify bursts in requests per second, either for all request
1493 types or for reads or writes only. Bursts allow the guest I/O to
1494 spike above the limit temporarily.
1496 ``iops_size=is``
1497 Let every is bytes of a request count as a new request for iops
1498 throttling purposes. Use this option to prevent guests from
1499 circumventing iops limits by sending fewer but larger requests.
1501 ``group=g``
1502 Join a throttling quota group with given name g. All drives that
1503 are members of the same group are accounted for together. Use
1504 this option to prevent guests from circumventing throttling
1505 limits by using many small disks instead of a single larger
1506 disk.
1508 By default, the ``cache.writeback=on`` mode is used. It will report
1509 data writes as completed as soon as the data is present in the host
1510 page cache. This is safe as long as your guest OS makes sure to
1511 correctly flush disk caches where needed. If your guest OS does not
1512 handle volatile disk write caches correctly and your host crashes or
1513 loses power, then the guest may experience data corruption.
1515 For such guests, you should consider using ``cache.writeback=off``.
1516 This means that the host page cache will be used to read and write
1517 data, but write notification will be sent to the guest only after
1518 QEMU has made sure to flush each write to the disk. Be aware that
1519 this has a major impact on performance.
1521 When using the ``-snapshot`` option, unsafe caching is always used.
1523 Copy-on-read avoids accessing the same backing file sectors
1524 repeatedly and is useful when the backing file is over a slow
1525 network. By default copy-on-read is off.
1527 Instead of ``-cdrom`` you can use:
1529 .. parsed-literal::
1531 |qemu_system| -drive file=file,index=2,media=cdrom
1533 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use:
1535 .. parsed-literal::
1537 |qemu_system| -drive file=file,index=0,media=disk
1538 |qemu_system| -drive file=file,index=1,media=disk
1539 |qemu_system| -drive file=file,index=2,media=disk
1540 |qemu_system| -drive file=file,index=3,media=disk
1542 You can open an image using pre-opened file descriptors from an fd
1543 set:
1545 .. parsed-literal::
1547 |qemu_system| \\
1548 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
1549 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
1550 -drive file=/dev/fdset/2,index=0,media=disk
1552 You can connect a CDROM to the slave of ide0:
1554 .. parsed-literal::
1556 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom
1558 If you don't specify the "file=" argument, you define an empty
1559 drive:
1561 .. parsed-literal::
1563 |qemu_system_x86| -drive if=ide,index=1,media=cdrom
1565 Instead of ``-fda``, ``-fdb``, you can use:
1567 .. parsed-literal::
1569 |qemu_system_x86| -drive file=file,index=0,if=floppy
1570 |qemu_system_x86| -drive file=file,index=1,if=floppy
1572 By default, interface is "ide" and index is automatically
1573 incremented:
1575 .. parsed-literal::
1577 |qemu_system_x86| -drive file=a -drive file=b"
1579 is interpreted like:
1581 .. parsed-literal::
1583 |qemu_system_x86| -hda a -hdb b
1584 ERST
1586 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1587 "-mtdblock file use 'file' as on-board Flash memory image\n",
1588 QEMU_ARCH_ALL)
1589 SRST
1590 ``-mtdblock file``
1591 Use file as on-board Flash memory image.
1592 ERST
1594 DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1595 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1596 SRST
1597 ``-sd file``
1598 Use file as SecureDigital card image.
1599 ERST
1601 DEF("snapshot", 0, QEMU_OPTION_snapshot,
1602 "-snapshot write to temporary files instead of disk image files\n",
1603 QEMU_ARCH_ALL)
1604 SRST
1605 ``-snapshot``
1606 Write to temporary files instead of disk image files. In this case,
1607 the raw disk image you use is not written back. You can however
1608 force the write back by pressing C-a s (see the :ref:`disk images`
1609 chapter in the System Emulation Users Guide).
1610 ERST
1612 DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1613 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1614 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n"
1615 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1616 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1617 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1618 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1619 " [[,throttling.iops-size=is]]\n"
1620 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n"
1621 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n"
1622 "-fsdev synth,id=id\n",
1623 QEMU_ARCH_ALL)
1625 SRST
1626 ``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]``
1628 ``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]``
1630 ``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]``
1632 ``-fsdev synth,id=id[,readonly=on]``
1633 Define a new file system device. Valid options are:
1635 ``local``
1636 Accesses to the filesystem are done by QEMU.
1638 ``proxy``
1639 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1641 ``synth``
1642 Synthetic filesystem, only used by QTests.
1644 ``id=id``
1645 Specifies identifier for this device.
1647 ``path=path``
1648 Specifies the export path for the file system device. Files
1649 under this path will be available to the 9p client on the guest.
1651 ``security_model=security_model``
1652 Specifies the security model to be used for this export path.
1653 Supported security models are "passthrough", "mapped-xattr",
1654 "mapped-file" and "none". In "passthrough" security model, files
1655 are stored using the same credentials as they are created on the
1656 guest. This requires QEMU to run as root. In "mapped-xattr"
1657 security model, some of the file attributes like uid, gid, mode
1658 bits and link target are stored as file attributes. For
1659 "mapped-file" these attributes are stored in the hidden
1660 .virtfs\_metadata directory. Directories exported by this
1661 security model cannot interact with other unix tools. "none"
1662 security model is same as passthrough except the sever won't
1663 report failures if it fails to set file attributes like
1664 ownership. Security model is mandatory only for local fsdriver.
1665 Other fsdrivers (like proxy) don't take security model as a
1666 parameter.
1668 ``writeout=writeout``
1669 This is an optional argument. The only supported value is
1670 "immediate". This means that host page cache will be used to
1671 read and write data but write notification will be sent to the
1672 guest only when the data has been reported as written by the
1673 storage subsystem.
1675 ``readonly=on``
1676 Enables exporting 9p share as a readonly mount for guests. By
1677 default read-write access is given.
1679 ``socket=socket``
1680 Enables proxy filesystem driver to use passed socket file for
1681 communicating with virtfs-proxy-helper(1).
1683 ``sock_fd=sock_fd``
1684 Enables proxy filesystem driver to use passed socket descriptor
1685 for communicating with virtfs-proxy-helper(1). Usually a helper
1686 like libvirt will create socketpair and pass one of the fds as
1687 sock\_fd.
1689 ``fmode=fmode``
1690 Specifies the default mode for newly created files on the host.
1691 Works only with security models "mapped-xattr" and
1692 "mapped-file".
1694 ``dmode=dmode``
1695 Specifies the default mode for newly created directories on the
1696 host. Works only with security models "mapped-xattr" and
1697 "mapped-file".
1699 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w``
1700 Specify bandwidth throttling limits in bytes per second, either
1701 for all request types or for reads or writes only.
1703 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm``
1704 Specify bursts in bytes per second, either for all request types
1705 or for reads or writes only. Bursts allow the guest I/O to spike
1706 above the limit temporarily.
1708 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w``
1709 Specify request rate limits in requests per second, either for
1710 all request types or for reads or writes only.
1712 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm``
1713 Specify bursts in requests per second, either for all request
1714 types or for reads or writes only. Bursts allow the guest I/O to
1715 spike above the limit temporarily.
1717 ``throttling.iops-size=is``
1718 Let every is bytes of a request count as a new request for iops
1719 throttling purposes.
1721 -fsdev option is used along with -device driver "virtio-9p-...".
1723 ``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag``
1724 Options for virtio-9p-... driver are:
1726 ``type``
1727 Specifies the variant to be used. Supported values are "pci",
1728 "ccw" or "device", depending on the machine type.
1730 ``fsdev=id``
1731 Specifies the id value specified along with -fsdev option.
1733 ``mount_tag=mount_tag``
1734 Specifies the tag name to be used by the guest to mount this
1735 export point.
1736 ERST
1738 DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1739 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1740 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n"
1741 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n"
1742 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n"
1743 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n",
1744 QEMU_ARCH_ALL)
1746 SRST
1747 ``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]``
1749 ``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1751 ``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1753 ``-virtfs synth,mount_tag=mount_tag``
1754 Define a new virtual filesystem device and expose it to the guest using
1755 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain
1756 directory on host is made directly accessible by guest as a pass-through
1757 file system by using the 9P network protocol for communication between
1758 host and guests, if desired even accessible, shared by several guests
1759 simultaniously.
1761 Note that ``-virtfs`` is actually just a convenience shortcut for its
1762 generalized form ``-fsdev -device virtio-9p-pci``.
1764 The general form of pass-through file system options are:
1766 ``local``
1767 Accesses to the filesystem are done by QEMU.
1769 ``proxy``
1770 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1772 ``synth``
1773 Synthetic filesystem, only used by QTests.
1775 ``id=id``
1776 Specifies identifier for the filesystem device
1778 ``path=path``
1779 Specifies the export path for the file system device. Files
1780 under this path will be available to the 9p client on the guest.
1782 ``security_model=security_model``
1783 Specifies the security model to be used for this export path.
1784 Supported security models are "passthrough", "mapped-xattr",
1785 "mapped-file" and "none". In "passthrough" security model, files
1786 are stored using the same credentials as they are created on the
1787 guest. This requires QEMU to run as root. In "mapped-xattr"
1788 security model, some of the file attributes like uid, gid, mode
1789 bits and link target are stored as file attributes. For
1790 "mapped-file" these attributes are stored in the hidden
1791 .virtfs\_metadata directory. Directories exported by this
1792 security model cannot interact with other unix tools. "none"
1793 security model is same as passthrough except the sever won't
1794 report failures if it fails to set file attributes like
1795 ownership. Security model is mandatory only for local fsdriver.
1796 Other fsdrivers (like proxy) don't take security model as a
1797 parameter.
1799 ``writeout=writeout``
1800 This is an optional argument. The only supported value is
1801 "immediate". This means that host page cache will be used to
1802 read and write data but write notification will be sent to the
1803 guest only when the data has been reported as written by the
1804 storage subsystem.
1806 ``readonly=on``
1807 Enables exporting 9p share as a readonly mount for guests. By
1808 default read-write access is given.
1810 ``socket=socket``
1811 Enables proxy filesystem driver to use passed socket file for
1812 communicating with virtfs-proxy-helper(1). Usually a helper like
1813 libvirt will create socketpair and pass one of the fds as
1814 sock\_fd.
1816 ``sock_fd``
1817 Enables proxy filesystem driver to use passed 'sock\_fd' as the
1818 socket descriptor for interfacing with virtfs-proxy-helper(1).
1820 ``fmode=fmode``
1821 Specifies the default mode for newly created files on the host.
1822 Works only with security models "mapped-xattr" and
1823 "mapped-file".
1825 ``dmode=dmode``
1826 Specifies the default mode for newly created directories on the
1827 host. Works only with security models "mapped-xattr" and
1828 "mapped-file".
1830 ``mount_tag=mount_tag``
1831 Specifies the tag name to be used by the guest to mount this
1832 export point.
1834 ``multidevs=multidevs``
1835 Specifies how to deal with multiple devices being shared with a
1836 9p export. Supported behaviours are either "remap", "forbid" or
1837 "warn". The latter is the default behaviour on which virtfs 9p
1838 expects only one device to be shared with the same export, and
1839 if more than one device is shared and accessed via the same 9p
1840 export then only a warning message is logged (once) by qemu on
1841 host side. In order to avoid file ID collisions on guest you
1842 should either create a separate virtfs export for each device to
1843 be shared with guests (recommended way) or you might use "remap"
1844 instead which allows you to share multiple devices with only one
1845 export instead, which is achieved by remapping the original
1846 inode numbers from host to guest in a way that would prevent
1847 such collisions. Remapping inodes in such use cases is required
1848 because the original device IDs from host are never passed and
1849 exposed on guest. Instead all files of an export shared with
1850 virtfs always share the same device id on guest. So two files
1851 with identical inode numbers but from actually different devices
1852 on host would otherwise cause a file ID collision and hence
1853 potential misbehaviours on guest. "forbid" on the other hand
1854 assumes like "warn" that only one device is shared by the same
1855 export, however it will not only log a warning message but also
1856 deny access to additional devices on guest. Note though that
1857 "forbid" does currently not block all possible file access
1858 operations (e.g. readdir() would still return entries from other
1859 devices).
1860 ERST
1862 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1863 "-iscsi [user=user][,password=password]\n"
1864 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1865 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1866 " [,timeout=timeout]\n"
1867 " iSCSI session parameters\n", QEMU_ARCH_ALL)
1869 SRST
1870 ``-iscsi``
1871 Configure iSCSI session parameters.
1872 ERST
1874 DEFHEADING()
1876 DEFHEADING(USB convenience options:)
1878 DEF("usb", 0, QEMU_OPTION_usb,
1879 "-usb enable on-board USB host controller (if not enabled by default)\n",
1880 QEMU_ARCH_ALL)
1881 SRST
1882 ``-usb``
1883 Enable USB emulation on machine types with an on-board USB host
1884 controller (if not enabled by default). Note that on-board USB host
1885 controllers may not support USB 3.0. In this case
1886 ``-device qemu-xhci`` can be used instead on machines with PCI.
1887 ERST
1889 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1890 "-usbdevice name add the host or guest USB device 'name'\n",
1891 QEMU_ARCH_ALL)
1892 SRST
1893 ``-usbdevice devname``
1894 Add the USB device devname, and enable an on-board USB controller
1895 if possible and necessary (just like it can be done via
1896 ``-machine usb=on``). Note that this option is mainly intended for
1897 the user's convenience only. More fine-grained control can be
1898 achieved by selecting a USB host controller (if necessary) and the
1899 desired USB device via the ``-device`` option instead. For example,
1900 instead of using ``-usbdevice mouse`` it is possible to use
1901 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse
1902 to a USB 3.0 controller instead (at least on machines that support
1903 PCI and do not have an USB controller enabled by default yet).
1904 For more details, see the chapter about
1905 :ref:`Connecting USB devices` in the System Emulation Users Guide.
1906 Possible devices for devname are:
1908 ``braille``
1909 Braille device. This will use BrlAPI to display the braille
1910 output on a real or fake device (i.e. it also creates a
1911 corresponding ``braille`` chardev automatically beside the
1912 ``usb-braille`` USB device).
1914 ``keyboard``
1915 Standard USB keyboard. Will override the PS/2 keyboard (if present).
1917 ``mouse``
1918 Virtual Mouse. This will override the PS/2 mouse emulation when
1919 activated.
1921 ``tablet``
1922 Pointer device that uses absolute coordinates (like a
1923 touchscreen). This means QEMU is able to report the mouse
1924 position without having to grab the mouse. Also overrides the
1925 PS/2 mouse emulation when activated.
1927 ``wacom-tablet``
1928 Wacom PenPartner USB tablet.
1931 ERST
1933 DEFHEADING()
1935 DEFHEADING(Display options:)
1937 DEF("display", HAS_ARG, QEMU_OPTION_display,
1938 #if defined(CONFIG_SPICE)
1939 "-display spice-app[,gl=on|off]\n"
1940 #endif
1941 #if defined(CONFIG_SDL)
1942 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n"
1943 " [,window-close=on|off]\n"
1944 #endif
1945 #if defined(CONFIG_GTK)
1946 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n"
1947 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n"
1948 #endif
1949 #if defined(CONFIG_VNC)
1950 "-display vnc=<display>[,<optargs>]\n"
1951 #endif
1952 #if defined(CONFIG_CURSES)
1953 "-display curses[,charset=<encoding>]\n"
1954 #endif
1955 #if defined(CONFIG_COCOA)
1956 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n"
1957 #endif
1958 #if defined(CONFIG_OPENGL)
1959 "-display egl-headless[,rendernode=<file>]\n"
1960 #endif
1961 #if defined(CONFIG_DBUS_DISPLAY)
1962 "-display dbus[,addr=<dbusaddr>]\n"
1963 " [,gl=on|core|es|off][,rendernode=<file>]\n"
1964 #endif
1965 #if defined(CONFIG_COCOA)
1966 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n"
1967 #endif
1968 "-display none\n"
1969 " select display backend type\n"
1970 " The default display is equivalent to\n "
1971 #if defined(CONFIG_GTK)
1972 "\"-display gtk\"\n"
1973 #elif defined(CONFIG_SDL)
1974 "\"-display sdl\"\n"
1975 #elif defined(CONFIG_COCOA)
1976 "\"-display cocoa\"\n"
1977 #elif defined(CONFIG_VNC)
1978 "\"-vnc localhost:0,to=99,id=default\"\n"
1979 #else
1980 "\"-display none\"\n"
1981 #endif
1982 , QEMU_ARCH_ALL)
1983 SRST
1984 ``-display type``
1985 Select type of display to use. Use ``-display help`` to list the available
1986 display types. Valid values for type are
1988 ``spice-app[,gl=on|off]``
1989 Start QEMU as a Spice server and launch the default Spice client
1990 application. The Spice server will redirect the serial consoles
1991 and QEMU monitors. (Since 4.0)
1993 ``dbus``
1994 Export the display over D-Bus interfaces. (Since 7.0)
1996 The connection is registered with the "org.qemu" name (and queued when
1997 already owned).
1999 ``addr=<dbusaddr>`` : D-Bus bus address to connect to.
2001 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``.
2003 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface
2004 will share framebuffers with DMABUF file descriptors).
2006 ``sdl``
2007 Display video output via SDL (usually in a separate graphics
2008 window; see the SDL documentation for other possibilities).
2009 Valid parameters are:
2011 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling
2012 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be
2013 either ``lshift-lctrl-lalt`` or ``rctrl``.
2015 ``gl=on|off|core|es`` : Use OpenGL for displaying
2017 ``show-cursor=on|off`` : Force showing the mouse cursor
2019 ``window-close=on|off`` : Allow to quit qemu with window close button
2021 ``gtk``
2022 Display video output in a GTK window. This interface provides
2023 drop-down menus and other UI elements to configure and control
2024 the VM during runtime. Valid parameters are:
2026 ``full-screen=on|off`` : Start in fullscreen mode
2028 ``gl=on|off`` : Use OpenGL for displaying
2030 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover
2032 ``show-tabs=on|off`` : Display the tab bar for switching between the
2033 various graphical interfaces (e.g. VGA and
2034 virtual console character devices) by default.
2036 ``show-cursor=on|off`` : Force showing the mouse cursor
2038 ``window-close=on|off`` : Allow to quit qemu with window close button
2040 ``curses[,charset=<encoding>]``
2041 Display video output via curses. For graphics device models
2042 which support a text mode, QEMU can display this output using a
2043 curses/ncurses interface. Nothing is displayed when the graphics
2044 device is in graphical mode or if the graphics device does not
2045 support a text mode. Generally only the VGA device models
2046 support text mode. The font charset used by the guest can be
2047 specified with the ``charset`` option, for example
2048 ``charset=CP850`` for IBM CP850 encoding. The default is
2049 ``CP437``.
2051 ``cocoa``
2052 Display video output in a Cocoa window. Mac only. This interface
2053 provides drop-down menus and other UI elements to configure and
2054 control the VM during runtime. Valid parameters are:
2056 ``show-cursor=on|off`` : Force showing the mouse cursor
2058 ``left-command-key=on|off`` : Disable forwarding left command key to host
2060 ``egl-headless[,rendernode=<file>]``
2061 Offload all OpenGL operations to a local DRI device. For any
2062 graphical display, this display needs to be paired with either
2063 VNC or SPICE displays.
2065 ``vnc=<display>``
2066 Start a VNC server on display <display>
2068 ``none``
2069 Do not display video output. The guest will still see an
2070 emulated graphics card, but its output will not be displayed to
2071 the QEMU user. This option differs from the -nographic option in
2072 that it only affects what is done with video output; -nographic
2073 also changes the destination of the serial and parallel port
2074 data.
2075 ERST
2077 DEF("nographic", 0, QEMU_OPTION_nographic,
2078 "-nographic disable graphical output and redirect serial I/Os to console\n",
2079 QEMU_ARCH_ALL)
2080 SRST
2081 ``-nographic``
2082 Normally, if QEMU is compiled with graphical window support, it
2083 displays output such as guest graphics, guest console, and the QEMU
2084 monitor in a window. With this option, you can totally disable
2085 graphical output so that QEMU is a simple command line application.
2086 The emulated serial port is redirected on the console and muxed with
2087 the monitor (unless redirected elsewhere explicitly). Therefore, you
2088 can still use QEMU to debug a Linux kernel with a serial console.
2089 Use C-a h for help on switching between the console and monitor.
2090 ERST
2092 #ifdef CONFIG_SPICE
2093 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
2094 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
2095 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
2096 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
2097 " [,x509-dh-key-file=<file>][,addr=addr]\n"
2098 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n"
2099 " [,tls-ciphers=<list>]\n"
2100 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
2101 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
2102 " [,sasl=on|off][,disable-ticketing=on|off]\n"
2103 " [,password=<string>][,password-secret=<secret-id>]\n"
2104 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
2105 " [,jpeg-wan-compression=[auto|never|always]]\n"
2106 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
2107 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
2108 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
2109 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
2110 " [,gl=[on|off]][,rendernode=<file>]\n"
2111 " enable spice\n"
2112 " at least one of {port, tls-port} is mandatory\n",
2113 QEMU_ARCH_ALL)
2114 #endif
2115 SRST
2116 ``-spice option[,option[,...]]``
2117 Enable the spice remote desktop protocol. Valid options are
2119 ``port=<nr>``
2120 Set the TCP port spice is listening on for plaintext channels.
2122 ``addr=<addr>``
2123 Set the IP address spice is listening on. Default is any
2124 address.
2126 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off``
2127 Force using the specified IP version.
2129 ``password=<string>``
2130 Set the password you need to authenticate.
2132 This option is deprecated and insecure because it leaves the
2133 password visible in the process listing. Use ``password-secret``
2134 instead.
2136 ``password-secret=<secret-id>``
2137 Set the ID of the ``secret`` object containing the password
2138 you need to authenticate.
2140 ``sasl=on|off``
2141 Require that the client use SASL to authenticate with the spice.
2142 The exact choice of authentication method used is controlled
2143 from the system / user's SASL configuration file for the 'qemu'
2144 service. This is typically found in /etc/sasl2/qemu.conf. If
2145 running QEMU as an unprivileged user, an environment variable
2146 SASL\_CONF\_PATH can be used to make it search alternate
2147 locations for the service config. While some SASL auth methods
2148 can also provide data encryption (eg GSSAPI), it is recommended
2149 that SASL always be combined with the 'tls' and 'x509' settings
2150 to enable use of SSL and server certificates. This ensures a
2151 data encryption preventing compromise of authentication
2152 credentials.
2154 ``disable-ticketing=on|off``
2155 Allow client connects without authentication.
2157 ``disable-copy-paste=on|off``
2158 Disable copy paste between the client and the guest.
2160 ``disable-agent-file-xfer=on|off``
2161 Disable spice-vdagent based file-xfer between the client and the
2162 guest.
2164 ``tls-port=<nr>``
2165 Set the TCP port spice is listening on for encrypted channels.
2167 ``x509-dir=<dir>``
2168 Set the x509 file directory. Expects same filenames as -vnc
2169 $display,x509=$dir
2171 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>``
2172 The x509 file names can also be configured individually.
2174 ``tls-ciphers=<list>``
2175 Specify which ciphers to use.
2177 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]``
2178 Force specific channel to be used with or without TLS
2179 encryption. The options can be specified multiple times to
2180 configure multiple channels. The special name "default" can be
2181 used to set the default mode. For channels which are not
2182 explicitly forced into one mode the spice client is allowed to
2183 pick tls/plaintext as he pleases.
2185 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]``
2186 Configure image compression (lossless). Default is auto\_glz.
2188 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]``
2189 Configure wan image compression (lossy for slow links). Default
2190 is auto.
2192 ``streaming-video=[off|all|filter]``
2193 Configure video stream detection. Default is off.
2195 ``agent-mouse=[on|off]``
2196 Enable/disable passing mouse events via vdagent. Default is on.
2198 ``playback-compression=[on|off]``
2199 Enable/disable audio stream compression (using celt 0.5.1).
2200 Default is on.
2202 ``seamless-migration=[on|off]``
2203 Enable/disable spice seamless migration. Default is off.
2205 ``gl=[on|off]``
2206 Enable/disable OpenGL context. Default is off.
2208 ``rendernode=<file>``
2209 DRM render node for OpenGL rendering. If not specified, it will
2210 pick the first available. (Since 2.9)
2211 ERST
2213 DEF("portrait", 0, QEMU_OPTION_portrait,
2214 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
2215 QEMU_ARCH_ALL)
2216 SRST
2217 ``-portrait``
2218 Rotate graphical output 90 deg left (only PXA LCD).
2219 ERST
2221 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
2222 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
2223 QEMU_ARCH_ALL)
2224 SRST
2225 ``-rotate deg``
2226 Rotate graphical output some deg left (only PXA LCD).
2227 ERST
2229 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
2230 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
2231 " select video card type\n", QEMU_ARCH_ALL)
2232 SRST
2233 ``-vga type``
2234 Select type of VGA card to emulate. Valid values for type are
2236 ``cirrus``
2237 Cirrus Logic GD5446 Video card. All Windows versions starting
2238 from Windows 95 should recognize and use this graphic card. For
2239 optimal performances, use 16 bit color depth in the guest and
2240 the host OS. (This card was the default before QEMU 2.2)
2242 ``std``
2243 Standard VGA card with Bochs VBE extensions. If your guest OS
2244 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if
2245 you want to use high resolution modes (>= 1280x1024x16) then you
2246 should use this option. (This card is the default since QEMU
2247 2.2)
2249 ``vmware``
2250 VMWare SVGA-II compatible adapter. Use it if you have
2251 sufficiently recent XFree86/XOrg server or Windows guest with a
2252 driver for this card.
2254 ``qxl``
2255 QXL paravirtual graphic card. It is VGA compatible (including
2256 VESA 2.0 VBE support). Works best with qxl guest drivers
2257 installed though. Recommended choice when using the spice
2258 protocol.
2260 ``tcx``
2261 (sun4m only) Sun TCX framebuffer. This is the default
2262 framebuffer for sun4m machines and offers both 8-bit and 24-bit
2263 colour depths at a fixed resolution of 1024x768.
2265 ``cg3``
2266 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit
2267 framebuffer for sun4m machines available in both 1024x768
2268 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people
2269 wishing to run older Solaris versions.
2271 ``virtio``
2272 Virtio VGA card.
2274 ``none``
2275 Disable VGA card.
2276 ERST
2278 DEF("full-screen", 0, QEMU_OPTION_full_screen,
2279 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
2280 SRST
2281 ``-full-screen``
2282 Start in full screen.
2283 ERST
2285 DEF("g", HAS_ARG, QEMU_OPTION_g ,
2286 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
2287 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
2288 SRST
2289 ``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]``
2290 Set the initial graphical resolution and depth (PPC, SPARC only).
2292 For PPC the default is 800x600x32.
2294 For SPARC with the TCX graphics device, the default is 1024x768x8
2295 with the option of 1024x768x24. For cgthree, the default is
2296 1024x768x8 with the option of 1152x900x8 for people who wish to use
2297 OBP.
2298 ERST
2300 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
2301 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
2302 SRST
2303 ``-vnc display[,option[,option[,...]]]``
2304 Normally, if QEMU is compiled with graphical window support, it
2305 displays output such as guest graphics, guest console, and the QEMU
2306 monitor in a window. With this option, you can have QEMU listen on
2307 VNC display display and redirect the VGA display over the VNC
2308 session. It is very useful to enable the usb tablet device when
2309 using this option (option ``-device usb-tablet``). When using the
2310 VNC display, you must use the ``-k`` parameter to set the keyboard
2311 layout if you are not using en-us. Valid syntax for the display is
2313 ``to=L``
2314 With this option, QEMU will try next available VNC displays,
2315 until the number L, if the origianlly defined "-vnc display" is
2316 not available, e.g. port 5900+display is already used by another
2317 application. By default, to=0.
2319 ``host:d``
2320 TCP connections will only be allowed from host on display d. By
2321 convention the TCP port is 5900+d. Optionally, host can be
2322 omitted in which case the server will accept connections from
2323 any host.
2325 ``unix:path``
2326 Connections will be allowed over UNIX domain sockets where path
2327 is the location of a unix socket to listen for connections on.
2329 ``none``
2330 VNC is initialized but not started. The monitor ``change``
2331 command can be used to later start the VNC server.
2333 Following the display value there may be one or more option flags
2334 separated by commas. Valid options are
2336 ``reverse=on|off``
2337 Connect to a listening VNC client via a "reverse" connection.
2338 The client is specified by the display. For reverse network
2339 connections (host:d,``reverse``), the d argument is a TCP port
2340 number, not a display number.
2342 ``websocket=on|off``
2343 Opens an additional TCP listening port dedicated to VNC
2344 Websocket connections. If a bare websocket option is given, the
2345 Websocket port is 5700+display. An alternative port can be
2346 specified with the syntax ``websocket``\ =port.
2348 If host is specified connections will only be allowed from this
2349 host. It is possible to control the websocket listen address
2350 independently, using the syntax ``websocket``\ =host:port.
2352 If no TLS credentials are provided, the websocket connection
2353 runs in unencrypted mode. If TLS credentials are provided, the
2354 websocket connection requires encrypted client connections.
2356 ``password=on|off``
2357 Require that password based authentication is used for client
2358 connections.
2360 The password must be set separately using the ``set_password``
2361 command in the :ref:`QEMU monitor`. The
2362 syntax to change your password is:
2363 ``set_password <protocol> <password>`` where <protocol> could be
2364 either "vnc" or "spice".
2366 If you would like to change <protocol> password expiration, you
2367 should use ``expire_password <protocol> <expiration-time>``
2368 where expiration time could be one of the following options:
2369 now, never, +seconds or UNIX time of expiration, e.g. +60 to
2370 make password expire in 60 seconds, or 1335196800 to make
2371 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for
2372 this date and time).
2374 You can also use keywords "now" or "never" for the expiration
2375 time to allow <protocol> password to expire immediately or never
2376 expire.
2378 ``password-secret=<secret-id>``
2379 Require that password based authentication is used for client
2380 connections, using the password provided by the ``secret``
2381 object identified by ``secret-id``.
2383 ``tls-creds=ID``
2384 Provides the ID of a set of TLS credentials to use to secure the
2385 VNC server. They will apply to both the normal VNC server socket
2386 and the websocket socket (if enabled). Setting TLS credentials
2387 will cause the VNC server socket to enable the VeNCrypt auth
2388 mechanism. The credentials should have been previously created
2389 using the ``-object tls-creds`` argument.
2391 ``tls-authz=ID``
2392 Provides the ID of the QAuthZ authorization object against which
2393 the client's x509 distinguished name will validated. This object
2394 is only resolved at time of use, so can be deleted and recreated
2395 on the fly while the VNC server is active. If missing, it will
2396 default to denying access.
2398 ``sasl=on|off``
2399 Require that the client use SASL to authenticate with the VNC
2400 server. The exact choice of authentication method used is
2401 controlled from the system / user's SASL configuration file for
2402 the 'qemu' service. This is typically found in
2403 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user,
2404 an environment variable SASL\_CONF\_PATH can be used to make it
2405 search alternate locations for the service config. While some
2406 SASL auth methods can also provide data encryption (eg GSSAPI),
2407 it is recommended that SASL always be combined with the 'tls'
2408 and 'x509' settings to enable use of SSL and server
2409 certificates. This ensures a data encryption preventing
2410 compromise of authentication credentials. See the
2411 :ref:`VNC security` section in the System Emulation Users Guide
2412 for details on using SASL authentication.
2414 ``sasl-authz=ID``
2415 Provides the ID of the QAuthZ authorization object against which
2416 the client's SASL username will validated. This object is only
2417 resolved at time of use, so can be deleted and recreated on the
2418 fly while the VNC server is active. If missing, it will default
2419 to denying access.
2421 ``acl=on|off``
2422 Legacy method for enabling authorization of clients against the
2423 x509 distinguished name and SASL username. It results in the
2424 creation of two ``authz-list`` objects with IDs of
2425 ``vnc.username`` and ``vnc.x509dname``. The rules for these
2426 objects must be configured with the HMP ACL commands.
2428 This option is deprecated and should no longer be used. The new
2429 ``sasl-authz`` and ``tls-authz`` options are a replacement.
2431 ``lossy=on|off``
2432 Enable lossy compression methods (gradient, JPEG, ...). If this
2433 option is set, VNC client may receive lossy framebuffer updates
2434 depending on its encoding settings. Enabling this option can
2435 save a lot of bandwidth at the expense of quality.
2437 ``non-adaptive=on|off``
2438 Disable adaptive encodings. Adaptive encodings are enabled by
2439 default. An adaptive encoding will try to detect frequently
2440 updated screen regions, and send updates in these regions using
2441 a lossy encoding (like JPEG). This can be really helpful to save
2442 bandwidth when playing videos. Disabling adaptive encodings
2443 restores the original static behavior of encodings like Tight.
2445 ``share=[allow-exclusive|force-shared|ignore]``
2446 Set display sharing policy. 'allow-exclusive' allows clients to
2447 ask for exclusive access. As suggested by the rfb spec this is
2448 implemented by dropping other connections. Connecting multiple
2449 clients in parallel requires all clients asking for a shared
2450 session (vncviewer: -shared switch). This is the default.
2451 'force-shared' disables exclusive client access. Useful for
2452 shared desktop sessions, where you don't want someone forgetting
2453 specify -shared disconnect everybody else. 'ignore' completely
2454 ignores the shared flag and allows everybody connect
2455 unconditionally. Doesn't conform to the rfb spec but is
2456 traditional QEMU behavior.
2458 ``key-delay-ms``
2459 Set keyboard delay, for key down and key up events, in
2460 milliseconds. Default is 10. Keyboards are low-bandwidth
2461 devices, so this slowdown can help the device and guest to keep
2462 up and not lose events in case events are arriving in bulk.
2463 Possible causes for the latter are flaky network connections, or
2464 scripts for automated testing.
2466 ``audiodev=audiodev``
2467 Use the specified audiodev when the VNC client requests audio
2468 transmission. When not using an -audiodev argument, this option
2469 must be omitted, otherwise is must be present and specify a
2470 valid audiodev.
2472 ``power-control=on|off``
2473 Permit the remote client to issue shutdown, reboot or reset power
2474 control requests.
2475 ERST
2477 ARCHHEADING(, QEMU_ARCH_I386)
2479 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2481 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2482 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2483 QEMU_ARCH_I386)
2484 SRST
2485 ``-win2k-hack``
2486 Use it when installing Windows 2000 to avoid a disk full bug. After
2487 Windows 2000 is installed, you no longer need this option (this
2488 option slows down the IDE transfers).
2489 ERST
2491 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2492 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2493 QEMU_ARCH_I386)
2494 SRST
2495 ``-no-fd-bootchk``
2496 Disable boot signature checking for floppy disks in BIOS. May be
2497 needed to boot from old floppy disks.
2498 ERST
2500 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2501 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2502 SRST
2503 ``-no-acpi``
2504 Disable ACPI (Advanced Configuration and Power Interface) support.
2505 Use it if your guest OS complains about ACPI problems (PC target
2506 machine only).
2507 ERST
2509 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2510 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2511 SRST
2512 ``-no-hpet``
2513 Disable HPET support.
2514 ERST
2516 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2517 "-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"
2518 " ACPI table description\n", QEMU_ARCH_I386)
2519 SRST
2520 ``-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]...]``
2521 Add ACPI table with specified header fields and context from
2522 specified files. For file=, take whole ACPI table from the specified
2523 files, including all ACPI headers (possible overridden by other
2524 options). For data=, only data portion of the table is used, all
2525 header information is specified in the command line. If a SLIC table
2526 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id
2527 fields will override the same in the RSDT and the FADT (a.k.a.
2528 FACP), in order to ensure the field matches required by the
2529 Microsoft SLIC spec and the ACPI spec.
2530 ERST
2532 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2533 "-smbios file=binary\n"
2534 " load SMBIOS entry from binary file\n"
2535 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2536 " [,uefi=on|off]\n"
2537 " specify SMBIOS type 0 fields\n"
2538 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2539 " [,uuid=uuid][,sku=str][,family=str]\n"
2540 " specify SMBIOS type 1 fields\n"
2541 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2542 " [,asset=str][,location=str]\n"
2543 " specify SMBIOS type 2 fields\n"
2544 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2545 " [,sku=str]\n"
2546 " specify SMBIOS type 3 fields\n"
2547 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2548 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
2549 " [,processor-id=%d]\n"
2550 " specify SMBIOS type 4 fields\n"
2551 "-smbios type=11[,value=str][,path=filename]\n"
2552 " specify SMBIOS type 11 fields\n"
2553 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2554 " [,asset=str][,part=str][,speed=%d]\n"
2555 " specify SMBIOS type 17 fields\n"
2556 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n"
2557 " specify SMBIOS type 41 fields\n",
2558 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2559 SRST
2560 ``-smbios file=binary``
2561 Load SMBIOS entry from binary file.
2563 ``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]``
2564 Specify SMBIOS type 0 fields
2566 ``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]``
2567 Specify SMBIOS type 1 fields
2569 ``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]``
2570 Specify SMBIOS type 2 fields
2572 ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
2573 Specify SMBIOS type 3 fields
2575 ``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]``
2576 Specify SMBIOS type 4 fields
2578 ``-smbios type=11[,value=str][,path=filename]``
2579 Specify SMBIOS type 11 fields
2581 This argument can be repeated multiple times, and values are added in the order they are parsed.
2582 Applications intending to use OEM strings data are encouraged to use their application name as
2583 a prefix for the value string. This facilitates passing information for multiple applications
2584 concurrently.
2586 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax
2587 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes.
2589 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to
2590 the SMBIOS table in the order in which they appear.
2592 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535
2593 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the
2594 guest. Instead it should be used as a indicator to inform the guest where to locate the real
2595 data set, for example, by specifying the serial ID of a block device.
2597 An example passing three strings is
2599 .. parsed-literal::
2601 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\
2602 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\
2603 path=/some/file/with/oemstringsdata.txt
2605 In the guest OS this is visible with the ``dmidecode`` command
2607 .. parsed-literal::
2609 $ dmidecode -t 11
2610 Handle 0x0E00, DMI type 11, 5 bytes
2611 OEM Strings
2612 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/
2613 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os
2614 String 3: myapp:some extra data
2617 ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
2618 Specify SMBIOS type 17 fields
2620 ``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]``
2621 Specify SMBIOS type 41 fields
2623 This argument can be repeated multiple times. Its main use is to allow network interfaces be created
2624 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface
2625 position on the PCI bus.
2627 Here is an example of use:
2629 .. parsed-literal::
2631 -netdev user,id=internet \\
2632 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\
2633 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev
2635 In the guest OS, the device should then appear as ``eno1``:
2637 ..parsed-literal::
2639 $ ip -brief l
2640 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
2641 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP>
2643 Currently, the PCI device has to be attached to the root bus.
2645 ERST
2647 DEFHEADING()
2649 DEFHEADING(Network options:)
2651 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2652 #ifdef CONFIG_SLIRP
2653 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n"
2654 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2655 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2656 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2657 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2658 #ifndef _WIN32
2659 "[,smb=dir[,smbserver=addr]]\n"
2660 #endif
2661 " configure a user mode network backend with ID 'str',\n"
2662 " its DHCP server and optional services\n"
2663 #endif
2664 #ifdef _WIN32
2665 "-netdev tap,id=str,ifname=name\n"
2666 " configure a host TAP network backend with ID 'str'\n"
2667 #else
2668 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2669 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2670 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2671 " [,poll-us=n]\n"
2672 " configure a host TAP network backend with ID 'str'\n"
2673 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2674 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2675 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2676 " to deconfigure it\n"
2677 " use '[down]script=no' to disable script execution\n"
2678 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2679 " configure it\n"
2680 " use 'fd=h' to connect to an already opened TAP interface\n"
2681 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2682 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2683 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2684 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2685 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2686 " use vhost=on to enable experimental in kernel accelerator\n"
2687 " (only has effect for virtio guests which use MSIX)\n"
2688 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2689 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2690 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2691 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2692 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n"
2693 " spent on busy polling for vhost net\n"
2694 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2695 " configure a host TAP network backend with ID 'str' that is\n"
2696 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2697 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2698 #endif
2699 #ifdef __linux__
2700 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2701 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n"
2702 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n"
2703 " [,rxcookie=rxcookie][,offset=offset]\n"
2704 " configure a network backend with ID 'str' connected to\n"
2705 " an Ethernet over L2TPv3 pseudowire.\n"
2706 " Linux kernel 3.3+ as well as most routers can talk\n"
2707 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2708 " VM to a router and even VM to Host. It is a nearly-universal\n"
2709 " standard (RFC3931). Note - this implementation uses static\n"
2710 " pre-configured tunnels (same as the Linux kernel).\n"
2711 " use 'src=' to specify source address\n"
2712 " use 'dst=' to specify destination address\n"
2713 " use 'udp=on' to specify udp encapsulation\n"
2714 " use 'srcport=' to specify source udp port\n"
2715 " use 'dstport=' to specify destination udp port\n"
2716 " use 'ipv6=on' to force v6\n"
2717 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2718 " well as a weak security measure\n"
2719 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2720 " use 'txcookie=0x012345678' to specify a txcookie\n"
2721 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2722 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2723 " use 'pincounter=on' to work around broken counter handling in peer\n"
2724 " use 'offset=X' to add an extra offset between header and data\n"
2725 #endif
2726 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2727 " configure a network backend to connect to another network\n"
2728 " using a socket connection\n"
2729 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2730 " configure a network backend to connect to a multicast maddr and port\n"
2731 " use 'localaddr=addr' to specify the host address to send packets from\n"
2732 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2733 " configure a network backend to connect to another network\n"
2734 " using an UDP tunnel\n"
2735 #ifdef CONFIG_VDE
2736 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2737 " configure a network backend to connect to port 'n' of a vde switch\n"
2738 " running on host and listening for incoming connections on 'socketpath'.\n"
2739 " Use group 'groupname' and mode 'octalmode' to change default\n"
2740 " ownership and permissions for communication port.\n"
2741 #endif
2742 #ifdef CONFIG_NETMAP
2743 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2744 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2745 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2746 " netmap device, defaults to '/dev/netmap')\n"
2747 #endif
2748 #ifdef CONFIG_POSIX
2749 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2750 " configure a vhost-user network, backed by a chardev 'dev'\n"
2751 #endif
2752 #ifdef __linux__
2753 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n"
2754 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n"
2755 #endif
2756 #ifdef CONFIG_VMNET
2757 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n"
2758 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n"
2759 " configure a vmnet network backend in host mode with ID 'str',\n"
2760 " isolate this interface from others with 'isolated',\n"
2761 " configure the address range and choose a subnet mask,\n"
2762 " specify network UUID 'uuid' to disable DHCP and interact with\n"
2763 " vmnet-host interfaces within this isolated network\n"
2764 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n"
2765 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n"
2766 " configure a vmnet network backend in shared mode with ID 'str',\n"
2767 " configure the address range and choose a subnet mask,\n"
2768 " set IPv6 ULA prefix (of length 64) to use for internal network,\n"
2769 " isolate this interface from others with 'isolated'\n"
2770 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n"
2771 " configure a vmnet network backend in bridged mode with ID 'str',\n"
2772 " use 'ifname=name' to select a physical network interface to be bridged,\n"
2773 " isolate this interface from others with 'isolated'\n"
2774 #endif
2775 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2776 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2777 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2778 "-nic [tap|bridge|"
2779 #ifdef CONFIG_SLIRP
2780 "user|"
2781 #endif
2782 #ifdef __linux__
2783 "l2tpv3|"
2784 #endif
2785 #ifdef CONFIG_VDE
2786 "vde|"
2787 #endif
2788 #ifdef CONFIG_NETMAP
2789 "netmap|"
2790 #endif
2791 #ifdef CONFIG_POSIX
2792 "vhost-user|"
2793 #endif
2794 #ifdef CONFIG_VMNET
2795 "vmnet-host|vmnet-shared|vmnet-bridged|"
2796 #endif
2797 "socket][,option][,...][mac=macaddr]\n"
2798 " initialize an on-board / default host NIC (using MAC address\n"
2799 " macaddr) and connect it to the given host network backend\n"
2800 "-nic none use it alone to have zero network devices (the default is to\n"
2801 " provided a 'user' network connection)\n",
2802 QEMU_ARCH_ALL)
2803 DEF("net", HAS_ARG, QEMU_OPTION_net,
2804 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2805 " configure or create an on-board (or machine default) NIC and\n"
2806 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2807 "-net ["
2808 #ifdef CONFIG_SLIRP
2809 "user|"
2810 #endif
2811 "tap|"
2812 "bridge|"
2813 #ifdef CONFIG_VDE
2814 "vde|"
2815 #endif
2816 #ifdef CONFIG_NETMAP
2817 "netmap|"
2818 #endif
2819 #ifdef CONFIG_VMNET
2820 "vmnet-host|vmnet-shared|vmnet-bridged|"
2821 #endif
2822 "socket][,option][,option][,...]\n"
2823 " old way to initialize a host network interface\n"
2824 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2825 SRST
2826 ``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
2827 This option is a shortcut for configuring both the on-board
2828 (default) guest NIC hardware and the host network backend in one go.
2829 The host backend options are the same as with the corresponding
2830 ``-netdev`` options below. The guest NIC model can be set with
2831 ``model=modelname``. Use ``model=help`` to list the available device
2832 types. The hardware MAC address can be set with ``mac=macaddr``.
2834 The following two example do exactly the same, to show how ``-nic``
2835 can be used to shorten the command line length:
2837 .. parsed-literal::
2839 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2840 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2842 ``-nic none``
2843 Indicate that no network devices should be configured. It is used to
2844 override the default configuration (default NIC with "user" host
2845 network backend) which is activated if no other networking options
2846 are provided.
2848 ``-netdev user,id=id[,option][,option][,...]``
2849 Configure user mode host network backend which requires no
2850 administrator privilege to run. Valid options are:
2852 ``id=id``
2853 Assign symbolic name for use in monitor commands.
2855 ``ipv4=on|off and ipv6=on|off``
2856 Specify that either IPv4 or IPv6 must be enabled. If neither is
2857 specified both protocols are enabled.
2859 ``net=addr[/mask]``
2860 Set IP network address the guest will see. Optionally specify
2861 the netmask, either in the form a.b.c.d or as number of valid
2862 top-most bits. Default is 10.0.2.0/24.
2864 ``host=addr``
2865 Specify the guest-visible address of the host. Default is the
2866 2nd IP in the guest network, i.e. x.x.x.2.
2868 ``ipv6-net=addr[/int]``
2869 Set IPv6 network address the guest will see (default is
2870 fec0::/64). The network prefix is given in the usual hexadecimal
2871 IPv6 address notation. The prefix size is optional, and is given
2872 as the number of valid top-most bits (default is 64).
2874 ``ipv6-host=addr``
2875 Specify the guest-visible IPv6 address of the host. Default is
2876 the 2nd IPv6 in the guest network, i.e. xxxx::2.
2878 ``restrict=on|off``
2879 If this option is enabled, the guest will be isolated, i.e. it
2880 will not be able to contact the host and no guest IP packets
2881 will be routed over the host to the outside. This option does
2882 not affect any explicitly set forwarding rules.
2884 ``hostname=name``
2885 Specifies the client hostname reported by the built-in DHCP
2886 server.
2888 ``dhcpstart=addr``
2889 Specify the first of the 16 IPs the built-in DHCP server can
2890 assign. Default is the 15th to 31st IP in the guest network,
2891 i.e. x.x.x.15 to x.x.x.31.
2893 ``dns=addr``
2894 Specify the guest-visible address of the virtual nameserver. The
2895 address must be different from the host address. Default is the
2896 3rd IP in the guest network, i.e. x.x.x.3.
2898 ``ipv6-dns=addr``
2899 Specify the guest-visible address of the IPv6 virtual
2900 nameserver. The address must be different from the host address.
2901 Default is the 3rd IP in the guest network, i.e. xxxx::3.
2903 ``dnssearch=domain``
2904 Provides an entry for the domain-search list sent by the
2905 built-in DHCP server. More than one domain suffix can be
2906 transmitted by specifying this option multiple times. If
2907 supported, this will cause the guest to automatically try to
2908 append the given domain suffix(es) in case a domain name can not
2909 be resolved.
2911 Example:
2913 .. parsed-literal::
2915 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2917 ``domainname=domain``
2918 Specifies the client domain name reported by the built-in DHCP
2919 server.
2921 ``tftp=dir``
2922 When using the user mode network stack, activate a built-in TFTP
2923 server. The files in dir will be exposed as the root of a TFTP
2924 server. The TFTP client on the guest must be configured in
2925 binary mode (use the command ``bin`` of the Unix TFTP client).
2927 ``tftp-server-name=name``
2928 In BOOTP reply, broadcast name as the "TFTP server name"
2929 (RFC2132 option 66). This can be used to advise the guest to
2930 load boot files or configurations from a different server than
2931 the host address.
2933 ``bootfile=file``
2934 When using the user mode network stack, broadcast file as the
2935 BOOTP filename. In conjunction with ``tftp``, this can be used
2936 to network boot a guest from a local directory.
2938 Example (using pxelinux):
2940 .. parsed-literal::
2942 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\
2943 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2945 ``smb=dir[,smbserver=addr]``
2946 When using the user mode network stack, activate a built-in SMB
2947 server so that Windows OSes can access to the host files in
2948 ``dir`` transparently. The IP address of the SMB server can be
2949 set to addr. By default the 4th IP in the guest network is used,
2950 i.e. x.x.x.4.
2952 In the guest Windows OS, the line:
2956 10.0.2.4 smbserver
2958 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
2959 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
2960 NT/2000).
2962 Then ``dir`` can be accessed in ``\\smbserver\qemu``.
2964 Note that a SAMBA server must be installed on the host OS.
2966 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport``
2967 Redirect incoming TCP or UDP connections to the host port
2968 hostport to the guest IP address guestaddr on guest port
2969 guestport. If guestaddr is not specified, its value is x.x.x.15
2970 (default first address given by the built-in DHCP server). By
2971 specifying hostaddr, the rule can be bound to a specific host
2972 interface. If no connection type is set, TCP is used. This
2973 option can be given multiple times.
2975 For example, to redirect host X11 connection from screen 1 to
2976 guest screen 0, use the following:
2978 .. parsed-literal::
2980 # on the host
2981 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2982 # this host xterm should open in the guest X11 server
2983 xterm -display :1
2985 To redirect telnet connections from host port 5555 to telnet
2986 port on the guest, use the following:
2988 .. parsed-literal::
2990 # on the host
2991 |qemu_system| -nic user,hostfwd=tcp::5555-:23
2992 telnet localhost 5555
2994 Then when you use on the host ``telnet localhost 5555``, you
2995 connect to the guest telnet server.
2997 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command``
2998 Forward guest TCP connections to the IP address server on port
2999 port to the character device dev or to a program executed by
3000 cmd:command which gets spawned for each connection. This option
3001 can be given multiple times.
3003 You can either use a chardev directly and have that one used
3004 throughout QEMU's lifetime, like in the following example:
3006 .. parsed-literal::
3008 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
3009 # the guest accesses it
3010 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
3012 Or you can execute a command on every TCP connection established
3013 by the guest, so that QEMU behaves similar to an inetd process
3014 for that virtual server:
3016 .. parsed-literal::
3018 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
3019 # and connect the TCP stream to its stdin/stdout
3020 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
3022 ``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]``
3023 Configure a host TAP network backend with ID id.
3025 Use the network script file to configure it and the network script
3026 dfile to deconfigure it. If name is not provided, the OS
3027 automatically provides one. The default network configure script is
3028 ``/etc/qemu-ifup`` and the default network deconfigure script is
3029 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to
3030 disable script execution.
3032 If running QEMU as an unprivileged user, use the network helper
3033 to configure the TAP interface and attach it to the bridge.
3034 The default network helper executable is
3035 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3036 ``br0``.
3038 ``fd``\ =h can be used to specify the handle of an already opened
3039 host TAP interface.
3041 Examples:
3043 .. parsed-literal::
3045 #launch a QEMU instance with the default network script
3046 |qemu_system| linux.img -nic tap
3048 .. parsed-literal::
3050 #launch a QEMU instance with two NICs, each one connected
3051 #to a TAP device
3052 |qemu_system| linux.img \\
3053 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\
3054 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
3056 .. parsed-literal::
3058 #launch a QEMU instance with the default network helper to
3059 #connect a TAP device to bridge br0
3060 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3061 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
3063 ``-netdev bridge,id=id[,br=bridge][,helper=helper]``
3064 Connect a host TAP network interface to a host bridge device.
3066 Use the network helper helper to configure the TAP interface and
3067 attach it to the bridge. The default network helper executable is
3068 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3069 ``br0``.
3071 Examples:
3073 .. parsed-literal::
3075 #launch a QEMU instance with the default network helper to
3076 #connect a TAP device to bridge br0
3077 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
3079 .. parsed-literal::
3081 #launch a QEMU instance with the default network helper to
3082 #connect a TAP device to bridge qemubr0
3083 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
3085 ``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]``
3086 This host network backend can be used to connect the guest's network
3087 to another QEMU virtual machine using a TCP socket connection. If
3088 ``listen`` is specified, QEMU waits for incoming connections on port
3089 (host is optional). ``connect`` is used to connect to another QEMU
3090 instance using the ``listen`` option. ``fd``\ =h specifies an
3091 already opened TCP socket.
3093 Example:
3095 .. parsed-literal::
3097 # launch a first QEMU instance
3098 |qemu_system| linux.img \\
3099 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3100 -netdev socket,id=n1,listen=:1234
3101 # connect the network of this instance to the network of the first instance
3102 |qemu_system| linux.img \\
3103 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3104 -netdev socket,id=n2,connect=127.0.0.1:1234
3106 ``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]``
3107 Configure a socket host network backend to share the guest's network
3108 traffic with another QEMU virtual machines using a UDP multicast
3109 socket, effectively making a bus for every QEMU with same multicast
3110 address maddr and port. NOTES:
3112 1. Several QEMU can be running on different hosts and share same bus
3113 (assuming correct multicast setup for these hosts).
3115 2. mcast support is compatible with User Mode Linux (argument
3116 ``ethN=mcast``), see http://user-mode-linux.sf.net.
3118 3. Use ``fd=h`` to specify an already opened UDP multicast socket.
3120 Example:
3122 .. parsed-literal::
3124 # launch one QEMU instance
3125 |qemu_system| linux.img \\
3126 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3127 -netdev socket,id=n1,mcast=230.0.0.1:1234
3128 # launch another QEMU instance on same "bus"
3129 |qemu_system| linux.img \\
3130 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3131 -netdev socket,id=n2,mcast=230.0.0.1:1234
3132 # launch yet another QEMU instance on same "bus"
3133 |qemu_system| linux.img \\
3134 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\
3135 -netdev socket,id=n3,mcast=230.0.0.1:1234
3137 Example (User Mode Linux compat.):
3139 .. parsed-literal::
3141 # launch QEMU instance (note mcast address selected is UML's default)
3142 |qemu_system| linux.img \\
3143 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3144 -netdev socket,id=n1,mcast=239.192.168.1:1102
3145 # launch UML
3146 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
3148 Example (send packets from host's 1.2.3.4):
3150 .. parsed-literal::
3152 |qemu_system| linux.img \\
3153 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3154 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
3156 ``-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]``
3157 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
3158 is a popular protocol to transport Ethernet (and other Layer 2) data
3159 frames between two systems. It is present in routers, firewalls and
3160 the Linux kernel (from version 3.3 onwards).
3162 This transport allows a VM to communicate to another VM, router or
3163 firewall directly.
3165 ``src=srcaddr``
3166 source address (mandatory)
3168 ``dst=dstaddr``
3169 destination address (mandatory)
3171 ``udp``
3172 select udp encapsulation (default is ip).
3174 ``srcport=srcport``
3175 source udp port.
3177 ``dstport=dstport``
3178 destination udp port.
3180 ``ipv6``
3181 force v6, otherwise defaults to v4.
3183 ``rxcookie=rxcookie``; \ ``txcookie=txcookie``
3184 Cookies are a weak form of security in the l2tpv3 specification.
3185 Their function is mostly to prevent misconfiguration. By default
3186 they are 32 bit.
3188 ``cookie64``
3189 Set cookie size to 64 bit instead of the default 32
3191 ``counter=off``
3192 Force a 'cut-down' L2TPv3 with no counter as in
3193 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
3195 ``pincounter=on``
3196 Work around broken counter handling in peer. This may also help
3197 on networks which have packet reorder.
3199 ``offset=offset``
3200 Add an extra offset between header and data
3202 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to
3203 the bridge br-lan on the remote Linux host 1.2.3.4:
3205 .. parsed-literal::
3207 # Setup tunnel on linux host using raw ip as encapsulation
3208 # on 1.2.3.4
3209 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\
3210 encap udp udp_sport 16384 udp_dport 16384
3211 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\
3212 0xFFFFFFFF peer_session_id 0xFFFFFFFF
3213 ifconfig vmtunnel0 mtu 1500
3214 ifconfig vmtunnel0 up
3215 brctl addif br-lan vmtunnel0
3218 # on 4.3.2.1
3219 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
3221 |qemu_system| linux.img -device e1000,netdev=n1 \\
3222 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
3224 ``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]``
3225 Configure VDE backend to connect to PORT n of a vde switch running
3226 on host and listening for incoming connections on socketpath. Use
3227 GROUP groupname and MODE octalmode to change default ownership and
3228 permissions for communication port. This option is only available if
3229 QEMU has been compiled with vde support enabled.
3231 Example:
3233 .. parsed-literal::
3235 # launch vde switch
3236 vde_switch -F -sock /tmp/myswitch
3237 # launch QEMU instance
3238 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch
3240 ``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
3241 Establish a vhost-user netdev, backed by a chardev id. The chardev
3242 should be a unix domain socket backed one. The vhost-user uses a
3243 specifically defined protocol to pass vhost ioctl replacement
3244 messages to an application on the other end of the socket. On
3245 non-MSIX guests, the feature can be forced with vhostforce. Use
3246 'queues=n' to specify the number of queues to be created for
3247 multiqueue vhost-user.
3249 Example:
3253 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
3254 -numa node,memdev=mem \
3255 -chardev socket,id=chr0,path=/path/to/socket \
3256 -netdev type=vhost-user,id=net0,chardev=chr0 \
3257 -device virtio-net-pci,netdev=net0
3259 ``-netdev vhost-vdpa,vhostdev=/path/to/dev``
3260 Establish a vhost-vdpa netdev.
3262 vDPA device is a device that uses a datapath which complies with
3263 the virtio specifications with a vendor specific control path.
3264 vDPA devices can be both physically located on the hardware or
3265 emulated by software.
3267 ``-netdev hubport,id=id,hubid=hubid[,netdev=nd]``
3268 Create a hub port on the emulated hub with ID hubid.
3270 The hubport netdev lets you connect a NIC to a QEMU emulated hub
3271 instead of a single netdev. Alternatively, you can also connect the
3272 hubport to another netdev with ID nd by using the ``netdev=nd``
3273 option.
3275 ``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]``
3276 Legacy option to configure or create an on-board (or machine
3277 default) Network Interface Card(NIC) and connect it either to the
3278 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd.
3279 If model is omitted, then the default NIC model associated with the
3280 machine type is used. Note that the default NIC model may change in
3281 future QEMU releases, so it is highly recommended to always specify
3282 a model. Optionally, the MAC address can be changed to mac, the
3283 device address set to addr (PCI cards only), and a name can be
3284 assigned for use in monitor commands. Optionally, for PCI cards, you
3285 can specify the number v of MSI-X vectors that the card should have;
3286 this option currently only affects virtio cards; set v = 0 to
3287 disable MSI-X. If no ``-net`` option is specified, a single NIC is
3288 created. QEMU can emulate several different models of network card.
3289 Use ``-net nic,model=help`` for a list of available devices for your
3290 target.
3292 ``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]``
3293 Configure a host network backend (with the options corresponding to
3294 the same ``-netdev`` option) and connect it to the emulated hub 0
3295 (the default hub). Use name to specify the name of the hub port.
3296 ERST
3298 DEFHEADING()
3300 DEFHEADING(Character device options:)
3302 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
3303 "-chardev help\n"
3304 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3305 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n"
3306 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
3307 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
3308 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
3309 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n"
3310 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
3311 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
3312 " [,logfile=PATH][,logappend=on|off]\n"
3313 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3314 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
3315 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3316 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
3317 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3318 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3319 #ifdef _WIN32
3320 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3321 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3322 #else
3323 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3324 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
3325 #endif
3326 #ifdef CONFIG_BRLAPI
3327 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3328 #endif
3329 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
3330 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
3331 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3332 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3333 #endif
3334 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
3335 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3336 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3337 #endif
3338 #if defined(CONFIG_SPICE)
3339 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3340 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3341 #endif
3342 , QEMU_ARCH_ALL
3345 SRST
3346 The general form of a character device option is:
3348 ``-chardev backend,id=id[,mux=on|off][,options]``
3349 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``,
3350 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``,
3351 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``,
3352 ``spicevmc``, ``spiceport``. The specific backend will determine the
3353 applicable options.
3355 Use ``-chardev help`` to print all available chardev backend types.
3357 All devices must have an id, which can be any string up to 127
3358 characters long. It is used to uniquely identify this device in
3359 other command line directives.
3361 A character device may be used in multiplexing mode by multiple
3362 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is
3363 a "1:N" device, and here the "1" end is your specified chardev
3364 backend, and the "N" end is the various parts of QEMU that can talk
3365 to a chardev. If you create a chardev with ``id=myid`` and
3366 ``mux=on``, QEMU will create a multiplexer with your specified ID,
3367 and you can then configure multiple front ends to use that chardev
3368 ID for their input/output. Up to four different front ends can be
3369 connected to a single multiplexed chardev. (Without multiplexing
3370 enabled, a chardev can only be used by a single front end.) For
3371 instance you could use this to allow a single stdio chardev to be
3372 used by two serial ports and the QEMU monitor:
3376 -chardev stdio,mux=on,id=char0 \
3377 -mon chardev=char0,mode=readline \
3378 -serial chardev:char0 \
3379 -serial chardev:char0
3381 You can have more than one multiplexer in a system configuration;
3382 for instance you could have a TCP port multiplexed between UART 0
3383 and UART 1, and stdio multiplexed between the QEMU monitor and a
3384 parallel port:
3388 -chardev stdio,mux=on,id=char0 \
3389 -mon chardev=char0,mode=readline \
3390 -parallel chardev:char0 \
3391 -chardev tcp,...,mux=on,id=char1 \
3392 -serial chardev:char1 \
3393 -serial chardev:char1
3395 When you're using a multiplexed character device, some escape
3396 sequences are interpreted in the input. See the chapter about
3397 :ref:`keys in the character backend multiplexer` in the
3398 System Emulation Users Guide for more details.
3400 Note that some other command line options may implicitly create
3401 multiplexed character backends; for instance ``-serial mon:stdio``
3402 creates a multiplexed stdio backend connected to the serial port and
3403 the QEMU monitor, and ``-nographic`` also multiplexes the console
3404 and the monitor to stdio.
3406 There is currently no support for multiplexing in the other
3407 direction (where a single QEMU front end takes input and output from
3408 multiple chardevs).
3410 Every backend supports the ``logfile`` option, which supplies the
3411 path to a file to record all data transmitted via the backend. The
3412 ``logappend`` option controls whether the log file will be truncated
3413 or appended to when opened.
3415 The available backends are:
3417 ``-chardev null,id=id``
3418 A void device. This device will not emit any data, and will drop any
3419 data it receives. The null backend does not take any options.
3421 ``-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]``
3422 Create a two-way stream socket, which can be either a TCP or a unix
3423 socket. A unix socket will be created if ``path`` is specified.
3424 Behaviour is undefined if TCP options are specified for a unix
3425 socket.
3427 ``server=on|off`` specifies that the socket shall be a listening socket.
3429 ``wait=on|off`` specifies that QEMU should not block waiting for a client
3430 to connect to a listening socket.
3432 ``telnet=on|off`` specifies that traffic on the socket should interpret
3433 telnet escape sequences.
3435 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for
3436 communication.
3438 ``reconnect`` sets the timeout for reconnecting on non-server
3439 sockets when the remote end goes away. qemu will delay this many
3440 seconds and then attempt to reconnect. Zero disables reconnecting,
3441 and is the default.
3443 ``tls-creds`` requests enablement of the TLS protocol for
3444 encryption, and specifies the id of the TLS credentials to use for
3445 the handshake. The credentials must be previously created with the
3446 ``-object tls-creds`` argument.
3448 ``tls-auth`` provides the ID of the QAuthZ authorization object
3449 against which the client's x509 distinguished name will be
3450 validated. This object is only resolved at time of use, so can be
3451 deleted and recreated on the fly while the chardev server is active.
3452 If missing, it will default to denying access.
3454 TCP and unix socket options are given below:
3456 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]``
3457 ``host`` for a listening socket specifies the local address to
3458 be bound. For a connecting socket species the remote host to
3459 connect to. ``host`` is optional for listening sockets. If not
3460 specified it defaults to ``0.0.0.0``.
3462 ``port`` for a listening socket specifies the local port to be
3463 bound. For a connecting socket specifies the port on the remote
3464 host to connect to. ``port`` can be given as either a port
3465 number or a service name. ``port`` is required.
3467 ``to`` is only relevant to listening sockets. If it is
3468 specified, and ``port`` cannot be bound, QEMU will attempt to
3469 bind to subsequent ports up to and including ``to`` until it
3470 succeeds. ``to`` must be specified as a port number.
3472 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4
3473 or IPv6 must be used. If neither is specified the socket may
3474 use either protocol.
3476 ``nodelay=on|off`` disables the Nagle algorithm.
3478 ``unix options: path=path[,abstract=on|off][,tight=on|off]``
3479 ``path`` specifies the local path of the unix socket. ``path``
3480 is required.
3481 ``abstract=on|off`` specifies the use of the abstract socket namespace,
3482 rather than the filesystem. Optional, defaults to false.
3483 ``tight=on|off`` sets the socket length of abstract sockets to their minimum,
3484 rather than the full sun_path length. Optional, defaults to true.
3486 ``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]``
3487 Sends all traffic from the guest to a remote host over UDP.
3489 ``host`` specifies the remote host to connect to. If not specified
3490 it defaults to ``localhost``.
3492 ``port`` specifies the port on the remote host to connect to.
3493 ``port`` is required.
3495 ``localaddr`` specifies the local address to bind to. If not
3496 specified it defaults to ``0.0.0.0``.
3498 ``localport`` specifies the local port to bind to. If not specified
3499 any available local port will be used.
3501 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used.
3502 If neither is specified the device may use either protocol.
3504 ``-chardev msmouse,id=id``
3505 Forward QEMU's emulated msmouse events to the guest. ``msmouse``
3506 does not take any options.
3508 ``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]``
3509 Connect to a QEMU text console. ``vc`` may optionally be given a
3510 specific size.
3512 ``width`` and ``height`` specify the width and height respectively
3513 of the console, in pixels.
3515 ``cols`` and ``rows`` specify that the console be sized to fit a
3516 text console with the given dimensions.
3518 ``-chardev ringbuf,id=id[,size=size]``
3519 Create a ring buffer with fixed size ``size``. size must be a power
3520 of two and defaults to ``64K``.
3522 ``-chardev file,id=id,path=path``
3523 Log all traffic received from the guest to a file.
3525 ``path`` specifies the path of the file to be opened. This file will
3526 be created if it does not already exist, and overwritten if it does.
3527 ``path`` is required.
3529 ``-chardev pipe,id=id,path=path``
3530 Create a two-way connection to the guest. The behaviour differs
3531 slightly between Windows hosts and other hosts:
3533 On Windows, a single duplex pipe will be created at
3534 ``\\.pipe\path``.
3536 On other hosts, 2 pipes will be created called ``path.in`` and
3537 ``path.out``. Data written to ``path.in`` will be received by the
3538 guest. Data written by the guest can be read from ``path.out``. QEMU
3539 will not create these fifos, and requires them to be present.
3541 ``path`` forms part of the pipe path as described above. ``path`` is
3542 required.
3544 ``-chardev console,id=id``
3545 Send traffic from the guest to QEMU's standard output. ``console``
3546 does not take any options.
3548 ``console`` is only available on Windows hosts.
3550 ``-chardev serial,id=id,path=path``
3551 Send traffic from the guest to a serial device on the host.
3553 On Unix hosts serial will actually accept any tty device, not only
3554 serial lines.
3556 ``path`` specifies the name of the serial device to open.
3558 ``-chardev pty,id=id``
3559 Create a new pseudo-terminal on the host and connect to it. ``pty``
3560 does not take any options.
3562 ``pty`` is not available on Windows hosts.
3564 ``-chardev stdio,id=id[,signal=on|off]``
3565 Connect to standard input and standard output of the QEMU process.
3567 ``signal`` controls if signals are enabled on the terminal, that
3568 includes exiting QEMU with the key sequence Control-c. This option
3569 is enabled by default, use ``signal=off`` to disable it.
3571 ``-chardev braille,id=id``
3572 Connect to a local BrlAPI server. ``braille`` does not take any
3573 options.
3575 ``-chardev tty,id=id,path=path``
3576 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD
3577 and DragonFlyBSD hosts. It is an alias for ``serial``.
3579 ``path`` specifies the path to the tty. ``path`` is required.
3581 ``-chardev parallel,id=id,path=path``
3583 ``-chardev parport,id=id,path=path``
3584 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD
3585 hosts.
3587 Connect to a local parallel port.
3589 ``path`` specifies the path to the parallel port device. ``path`` is
3590 required.
3592 ``-chardev spicevmc,id=id,debug=debug,name=name``
3593 ``spicevmc`` is only available when spice support is built in.
3595 ``debug`` debug level for spicevmc
3597 ``name`` name of spice channel to connect to
3599 Connect to a spice virtual machine channel, such as vdiport.
3601 ``-chardev spiceport,id=id,debug=debug,name=name``
3602 ``spiceport`` is only available when spice support is built in.
3604 ``debug`` debug level for spicevmc
3606 ``name`` name of spice port to connect to
3608 Connect to a spice port, allowing a Spice client to handle the
3609 traffic identified by a name (preferably a fqdn).
3610 ERST
3612 DEFHEADING()
3614 #ifdef CONFIG_TPM
3615 DEFHEADING(TPM device options:)
3617 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3618 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3619 " use path to provide path to a character device; default is /dev/tpm0\n"
3620 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3621 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3622 "-tpmdev emulator,id=id,chardev=dev\n"
3623 " configure the TPM device using chardev backend\n",
3624 QEMU_ARCH_ALL)
3625 SRST
3626 The general form of a TPM device option is:
3628 ``-tpmdev backend,id=id[,options]``
3629 The specific backend type will determine the applicable options. The
3630 ``-tpmdev`` option creates the TPM backend and requires a
3631 ``-device`` option that specifies the TPM frontend interface model.
3633 Use ``-tpmdev help`` to print all available TPM backend types.
3635 The available backends are:
3637 ``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path``
3638 (Linux-host only) Enable access to the host's TPM using the
3639 passthrough driver.
3641 ``path`` specifies the path to the host's TPM device, i.e., on a
3642 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by
3643 default ``/dev/tpm0`` is used.
3645 ``cancel-path`` specifies the path to the host TPM device's sysfs
3646 entry allowing for cancellation of an ongoing TPM command.
3647 ``cancel-path`` is optional and by default QEMU will search for the
3648 sysfs entry to use.
3650 Some notes about using the host's TPM with the passthrough driver:
3652 The TPM device accessed by the passthrough driver must not be used
3653 by any other application on the host.
3655 Since the host's firmware (BIOS/UEFI) has already initialized the
3656 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize
3657 the TPM again and may therefore not show a TPM-specific menu that
3658 would otherwise allow the user to configure the TPM, e.g., allow the
3659 user to enable/disable or activate/deactivate the TPM. Further, if
3660 TPM ownership is released from within a VM then the host's TPM will
3661 get disabled and deactivated. To enable and activate the TPM again
3662 afterwards, the host has to be rebooted and the user is required to
3663 enter the firmware's menu to enable and activate the TPM. If the TPM
3664 is left disabled and/or deactivated most TPM commands will fail.
3666 To create a passthrough TPM use the following two options:
3670 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3672 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by
3673 ``tpmdev=tpm0`` in the device option.
3675 ``-tpmdev emulator,id=id,chardev=dev``
3676 (Linux-host only) Enable access to a TPM emulator using Unix domain
3677 socket based chardev backend.
3679 ``chardev`` specifies the unique ID of a character device backend
3680 that provides connection to the software TPM server.
3682 To create a TPM emulator backend device with chardev socket backend:
3686 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3687 ERST
3689 DEFHEADING()
3691 #endif
3693 DEFHEADING(Boot Image or Kernel specific:)
3694 SRST
3695 There are broadly 4 ways you can boot a system with QEMU.
3697 - specify a firmware and let it control finding a kernel
3698 - specify a firmware and pass a hint to the kernel to boot
3699 - direct kernel image boot
3700 - manually load files into the guest's address space
3702 The third method is useful for quickly testing kernels but as there is
3703 no firmware to pass configuration information to the kernel the
3704 hardware must either be probeable, the kernel built for the exact
3705 configuration or passed some configuration data (e.g. a DTB blob)
3706 which tells the kernel what drivers it needs. This exact details are
3707 often hardware specific.
3709 The final method is the most generic way of loading images into the
3710 guest address space and used mostly for ``bare metal`` type
3711 development where the reset vectors of the processor are taken into
3712 account.
3714 ERST
3716 SRST
3718 For x86 machines and some other architectures ``-bios`` will generally
3719 do the right thing with whatever it is given. For other machines the
3720 more strict ``-pflash`` option needs an image that is sized for the
3721 flash device for the given machine type.
3723 Please see the :ref:`system-targets-ref` section of the manual for
3724 more detailed documentation.
3726 ERST
3728 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3729 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3730 SRST
3731 ``-bios file``
3732 Set the filename for the BIOS.
3733 ERST
3735 DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
3736 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
3737 SRST
3738 ``-pflash file``
3739 Use file as a parallel flash image.
3740 ERST
3742 SRST
3744 The kernel options were designed to work with Linux kernels although
3745 other things (like hypervisors) can be packaged up as a kernel
3746 executable image. The exact format of a executable image is usually
3747 architecture specific.
3749 The way in which the kernel is started (what address it is loaded at,
3750 what if any information is passed to it via CPU registers, the state
3751 of the hardware when it is started, and so on) is also architecture
3752 specific. Typically it follows the specification laid down by the
3753 Linux kernel for how kernels for that architecture must be started.
3755 ERST
3757 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3758 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3759 SRST
3760 ``-kernel bzImage``
3761 Use bzImage as kernel image. The kernel can be either a Linux kernel
3762 or in multiboot format.
3763 ERST
3765 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3766 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3767 SRST
3768 ``-append cmdline``
3769 Use cmdline as kernel command line
3770 ERST
3772 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3773 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3774 SRST
3775 ``-initrd file``
3776 Use file as initial ram disk.
3778 ``-initrd "file1 arg=foo,file2"``
3779 This syntax is only available with multiboot.
3781 Use file1 and file2 as modules and pass arg=foo as parameter to the
3782 first module.
3783 ERST
3785 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3786 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3787 SRST
3788 ``-dtb file``
3789 Use file as a device tree binary (dtb) image and pass it to the
3790 kernel on boot.
3791 ERST
3793 SRST
3795 Finally you can also manually load images directly into the address
3796 space of the guest. This is most useful for developers who already
3797 know the layout of their guest and take care to ensure something sane
3798 will happen when the reset vector executes.
3800 The generic loader can be invoked by using the loader device:
3802 ``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]``
3804 there is also the guest loader which operates in a similar way but
3805 tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where
3806 the guest image is:
3808 ``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]``
3810 ERST
3812 DEFHEADING()
3814 DEFHEADING(Debug/Expert options:)
3816 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
3817 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
3818 " Policy for handling deprecated management interfaces\n"
3819 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n"
3820 " Policy for handling unstable management interfaces\n",
3821 QEMU_ARCH_ALL)
3822 SRST
3823 ``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]``
3824 Set policy for handling deprecated management interfaces (experimental):
3826 ``deprecated-input=accept`` (default)
3827 Accept deprecated commands and arguments
3828 ``deprecated-input=reject``
3829 Reject deprecated commands and arguments
3830 ``deprecated-input=crash``
3831 Crash on deprecated commands and arguments
3832 ``deprecated-output=accept`` (default)
3833 Emit deprecated command results and events
3834 ``deprecated-output=hide``
3835 Suppress deprecated command results and events
3837 Limitation: covers only syntactic aspects of QMP.
3839 ``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]``
3840 Set policy for handling unstable management interfaces (experimental):
3842 ``unstable-input=accept`` (default)
3843 Accept unstable commands and arguments
3844 ``unstable-input=reject``
3845 Reject unstable commands and arguments
3846 ``unstable-input=crash``
3847 Crash on unstable commands and arguments
3848 ``unstable-output=accept`` (default)
3849 Emit unstable command results and events
3850 ``unstable-output=hide``
3851 Suppress unstable command results and events
3853 Limitation: covers only syntactic aspects of QMP.
3854 ERST
3856 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3857 "-fw_cfg [name=]<name>,file=<file>\n"
3858 " add named fw_cfg entry with contents from file\n"
3859 "-fw_cfg [name=]<name>,string=<str>\n"
3860 " add named fw_cfg entry with contents from string\n",
3861 QEMU_ARCH_ALL)
3862 SRST
3863 ``-fw_cfg [name=]name,file=file``
3864 Add named fw\_cfg entry with contents from file file.
3866 ``-fw_cfg [name=]name,string=str``
3867 Add named fw\_cfg entry with contents from string str.
3869 The terminating NUL character of the contents of str will not be
3870 included as part of the fw\_cfg item data. To insert contents with
3871 embedded NUL characters, you have to use the file parameter.
3873 The fw\_cfg entries are passed by QEMU through to the guest.
3875 Example:
3879 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3881 creates an fw\_cfg entry named opt/com.mycompany/blob with contents
3882 from ./my\_blob.bin.
3883 ERST
3885 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3886 "-serial dev redirect the serial port to char device 'dev'\n",
3887 QEMU_ARCH_ALL)
3888 SRST
3889 ``-serial dev``
3890 Redirect the virtual serial port to host character device dev. The
3891 default device is ``vc`` in graphical mode and ``stdio`` in non
3892 graphical mode.
3894 This option can be used several times to simulate up to 4 serial
3895 ports.
3897 Use ``-serial none`` to disable all serial ports.
3899 Available character devices are:
3901 ``vc[:WxH]``
3902 Virtual console. Optionally, a width and height can be given in
3903 pixel with
3907 vc:800x600
3909 It is also possible to specify width or height in characters:
3913 vc:80Cx24C
3915 ``pty``
3916 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3918 ``none``
3919 No device is allocated.
3921 ``null``
3922 void device
3924 ``chardev:id``
3925 Use a named character device defined with the ``-chardev``
3926 option.
3928 ``/dev/XXX``
3929 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial
3930 port parameters are set according to the emulated ones.
3932 ``/dev/parportN``
3933 [Linux only, parallel port only] Use host parallel port N.
3934 Currently SPP and EPP parallel port features can be used.
3936 ``file:filename``
3937 Write output to filename. No character can be read.
3939 ``stdio``
3940 [Unix only] standard input/output
3942 ``pipe:filename``
3943 name pipe filename
3945 ``COMn``
3946 [Windows only] Use host serial port n
3948 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]``
3949 This implements UDP Net Console. When remote\_host or src\_ip
3950 are not specified they default to ``0.0.0.0``. When not using a
3951 specified src\_port a random port is automatically chosen.
3953 If you just want a simple readonly console you can use
3954 ``netcat`` or ``nc``, by starting QEMU with:
3955 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time
3956 QEMU writes something to that port it will appear in the
3957 netconsole session.
3959 If you plan to send characters back via netconsole or you want
3960 to stop and start QEMU a lot of times, you should have QEMU use
3961 the same source port each time by using something like ``-serial
3962 udp::4555@:4556`` to QEMU. Another approach is to use a patched
3963 version of netcat which can listen to a TCP port and send and
3964 receive characters via udp. If you have a patched version of
3965 netcat which activates telnet remote echo and single char
3966 transfer, then you can use the following options to set up a
3967 netcat redirector to allow telnet on port 5555 to access the
3968 QEMU port.
3970 ``QEMU Options:``
3971 -serial udp::4555@:4556
3973 ``netcat options:``
3974 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3976 ``telnet options:``
3977 localhost 5555
3979 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]``
3980 The TCP Net Console has two modes of operation. It can send the
3981 serial I/O to a location or wait for a connection from a
3982 location. By default the TCP Net Console is sent to host at the
3983 port. If you use the ``server=on`` option QEMU will wait for a client
3984 socket application to connect to the port before continuing,
3985 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off``
3986 option disables the Nagle buffering algorithm. The ``reconnect=on``
3987 option only applies if ``server=no`` is set, if the connection goes
3988 down it will attempt to reconnect at the given interval. If host
3989 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a
3990 time is accepted. You can use ``telnet=on`` to connect to the
3991 corresponding character device.
3993 ``Example to send tcp console to 192.168.0.2 port 4444``
3994 -serial tcp:192.168.0.2:4444
3996 ``Example to listen and wait on port 4444 for connection``
3997 -serial tcp::4444,server=on
3999 ``Example to not wait and listen on ip 192.168.0.100 port 4444``
4000 -serial tcp:192.168.0.100:4444,server=on,wait=off
4002 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]``
4003 The telnet protocol is used instead of raw tcp sockets. The
4004 options work the same as if you had specified ``-serial tcp``.
4005 The difference is that the port acts like a telnet server or
4006 client using telnet option negotiation. This will also allow you
4007 to send the MAGIC\_SYSRQ sequence if you use a telnet that
4008 supports sending the break sequence. Typically in unix telnet
4009 you do it with Control-] and then type "send break" followed by
4010 pressing the enter key.
4012 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]``
4013 The WebSocket protocol is used instead of raw tcp socket. The
4014 port acts as a WebSocket server. Client mode is not supported.
4016 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]``
4017 A unix domain socket is used instead of a tcp socket. The option
4018 works the same as if you had specified ``-serial tcp`` except
4019 the unix domain socket path is used for connections.
4021 ``mon:dev_string``
4022 This is a special option to allow the monitor to be multiplexed
4023 onto another serial port. The monitor is accessed with key
4024 sequence of Control-a and then pressing c. dev\_string should be
4025 any one of the serial devices specified above. An example to
4026 multiplex the monitor onto a telnet server listening on port
4027 4444 would be:
4029 ``-serial mon:telnet::4444,server=on,wait=off``
4031 When the monitor is multiplexed to stdio in this way, Ctrl+C
4032 will not terminate QEMU any more but will be passed to the guest
4033 instead.
4035 ``braille``
4036 Braille device. This will use BrlAPI to display the braille
4037 output on a real or fake device.
4039 ``msmouse``
4040 Three button serial mouse. Configure the guest to use Microsoft
4041 protocol.
4042 ERST
4044 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
4045 "-parallel dev redirect the parallel port to char device 'dev'\n",
4046 QEMU_ARCH_ALL)
4047 SRST
4048 ``-parallel dev``
4049 Redirect the virtual parallel port to host device dev (same devices
4050 as the serial port). On Linux hosts, ``/dev/parportN`` can be used
4051 to use hardware devices connected on the corresponding host parallel
4052 port.
4054 This option can be used several times to simulate up to 3 parallel
4055 ports.
4057 Use ``-parallel none`` to disable all parallel ports.
4058 ERST
4060 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
4061 "-monitor dev redirect the monitor to char device 'dev'\n",
4062 QEMU_ARCH_ALL)
4063 SRST
4064 ``-monitor dev``
4065 Redirect the monitor to host device dev (same devices as the serial
4066 port). The default device is ``vc`` in graphical mode and ``stdio``
4067 in non graphical mode. Use ``-monitor none`` to disable the default
4068 monitor.
4069 ERST
4070 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
4071 "-qmp dev like -monitor but opens in 'control' mode\n",
4072 QEMU_ARCH_ALL)
4073 SRST
4074 ``-qmp dev``
4075 Like -monitor but opens in 'control' mode.
4076 ERST
4077 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
4078 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
4079 QEMU_ARCH_ALL)
4080 SRST
4081 ``-qmp-pretty dev``
4082 Like -qmp but uses pretty JSON formatting.
4083 ERST
4085 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
4086 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
4087 SRST
4088 ``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
4089 Setup monitor on chardev name. ``mode=control`` configures
4090 a QMP monitor (a JSON RPC-style protocol) and it is not the
4091 same as HMP, the human monitor that has a "(qemu)" prompt.
4092 ``pretty`` is only valid when ``mode=control``,
4093 turning on JSON pretty printing to ease
4094 human reading and debugging.
4095 ERST
4097 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
4098 "-debugcon dev redirect the debug console to char device 'dev'\n",
4099 QEMU_ARCH_ALL)
4100 SRST
4101 ``-debugcon dev``
4102 Redirect the debug console to host device dev (same devices as the
4103 serial port). The debug console is an I/O port which is typically
4104 port 0xe9; writing to that I/O port sends output to this device. The
4105 default device is ``vc`` in graphical mode and ``stdio`` in non
4106 graphical mode.
4107 ERST
4109 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
4110 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
4111 SRST
4112 ``-pidfile file``
4113 Store the QEMU process PID in file. It is useful if you launch QEMU
4114 from a script.
4115 ERST
4117 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
4118 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL)
4119 SRST
4120 ``-singlestep``
4121 Run the emulation in single step mode.
4122 ERST
4124 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
4125 "--preconfig pause QEMU before machine is initialized (experimental)\n",
4126 QEMU_ARCH_ALL)
4127 SRST
4128 ``--preconfig``
4129 Pause QEMU for interactive configuration before the machine is
4130 created, which allows querying and configuring properties that will
4131 affect machine initialization. Use QMP command 'x-exit-preconfig' to
4132 exit the preconfig state and move to the next state (i.e. run guest
4133 if -S isn't used or pause the second time if -S is used). This
4134 option is experimental.
4135 ERST
4137 DEF("S", 0, QEMU_OPTION_S, \
4138 "-S freeze CPU at startup (use 'c' to start execution)\n",
4139 QEMU_ARCH_ALL)
4140 SRST
4141 ``-S``
4142 Do not start CPU at startup (you must type 'c' in the monitor).
4143 ERST
4145 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
4146 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
4147 " run qemu with overcommit hints\n"
4148 " mem-lock=on|off controls memory lock support (default: off)\n"
4149 " cpu-pm=on|off controls cpu power management (default: off)\n",
4150 QEMU_ARCH_ALL)
4151 SRST
4152 ``-overcommit mem-lock=on|off``
4154 ``-overcommit cpu-pm=on|off``
4155 Run qemu with hints about host resource overcommit. The default is
4156 to assume that host overcommits all resources.
4158 Locking qemu and guest memory can be enabled via ``mem-lock=on``
4159 (disabled by default). This works when host memory is not
4160 overcommitted and reduces the worst-case latency for guest.
4162 Guest ability to manage power state of host cpus (increasing latency
4163 for other processes on the same host cpu, but decreasing latency for
4164 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This
4165 works best when host CPU is not overcommitted. When used, host
4166 estimates of CPU cycle and power utilization will be incorrect, not
4167 taking into account guest idle time.
4168 ERST
4170 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
4171 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n"
4172 " the guest without waiting for gdb to connect; use -S too\n"
4173 " if you want it to not start execution.)\n",
4174 QEMU_ARCH_ALL)
4175 SRST
4176 ``-gdb dev``
4177 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter
4178 in the System Emulation Users Guide). Note that this option does not pause QEMU
4179 execution -- if you want QEMU to not start the guest until you
4180 connect with gdb and issue a ``continue`` command, you will need to
4181 also pass the ``-S`` option to QEMU.
4183 The most usual configuration is to listen on a local TCP socket::
4185 -gdb tcp::3117
4187 but you can specify other backends; UDP, pseudo TTY, or even stdio
4188 are all reasonable use cases. For example, a stdio connection
4189 allows you to start QEMU from within gdb and establish the
4190 connection via a pipe:
4192 .. parsed-literal::
4194 (gdb) target remote | exec |qemu_system| -gdb stdio ...
4195 ERST
4197 DEF("s", 0, QEMU_OPTION_s, \
4198 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
4199 QEMU_ARCH_ALL)
4200 SRST
4201 ``-s``
4202 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
4203 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide).
4204 ERST
4206 DEF("d", HAS_ARG, QEMU_OPTION_d, \
4207 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
4208 QEMU_ARCH_ALL)
4209 SRST
4210 ``-d item1[,...]``
4211 Enable logging of specified items. Use '-d help' for a list of log
4212 items.
4213 ERST
4215 DEF("D", HAS_ARG, QEMU_OPTION_D, \
4216 "-D logfile output log to logfile (default stderr)\n",
4217 QEMU_ARCH_ALL)
4218 SRST
4219 ``-D logfile``
4220 Output log in logfile instead of to stderr
4221 ERST
4223 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
4224 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
4225 QEMU_ARCH_ALL)
4226 SRST
4227 ``-dfilter range1[,...]``
4228 Filter debug output to that relevant to a range of target addresses.
4229 The filter spec can be either start+size, start-size or start..end
4230 where start end and size are the addresses and sizes required. For
4231 example:
4235 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
4237 Will dump output for any code in the 0x1000 sized block starting at
4238 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and
4239 another 0x1000 sized block starting at 0xffffffc00005f000.
4240 ERST
4242 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
4243 "-seed number seed the pseudo-random number generator\n",
4244 QEMU_ARCH_ALL)
4245 SRST
4246 ``-seed number``
4247 Force the guest to use a deterministic pseudo-random number
4248 generator, seeded with number. This does not affect crypto routines
4249 within the host.
4250 ERST
4252 DEF("L", HAS_ARG, QEMU_OPTION_L, \
4253 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
4254 QEMU_ARCH_ALL)
4255 SRST
4256 ``-L path``
4257 Set the directory for the BIOS, VGA BIOS and keymaps.
4259 To list all the data directories, use ``-L help``.
4260 ERST
4262 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
4263 "-enable-kvm enable KVM full virtualization support\n",
4264 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC |
4265 QEMU_ARCH_RISCV | QEMU_ARCH_S390X)
4266 SRST
4267 ``-enable-kvm``
4268 Enable KVM full virtualization support. This option is only
4269 available if KVM support is enabled when compiling.
4270 ERST
4272 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
4273 "-xen-domid id specify xen guest domain id\n",
4274 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4275 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
4276 "-xen-attach attach to existing xen domain\n"
4277 " libxl will use this when starting QEMU\n",
4278 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4279 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
4280 "-xen-domid-restrict restrict set of available xen operations\n"
4281 " to specified domain id. (Does not affect\n"
4282 " xenpv machine type).\n",
4283 QEMU_ARCH_ARM | QEMU_ARCH_I386)
4284 SRST
4285 ``-xen-domid id``
4286 Specify xen guest domain id (XEN only).
4288 ``-xen-attach``
4289 Attach to existing xen domain. libxl will use this when starting
4290 QEMU (XEN only). Restrict set of available xen operations to
4291 specified domain id (XEN only).
4292 ERST
4294 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
4295 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
4296 SRST
4297 ``-no-reboot``
4298 Exit instead of rebooting.
4299 ERST
4301 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
4302 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
4303 SRST
4304 ``-no-shutdown``
4305 Don't exit QEMU on guest shutdown, but instead only stop the
4306 emulation. This allows for instance switching to monitor to commit
4307 changes to the disk image.
4308 ERST
4310 DEF("action", HAS_ARG, QEMU_OPTION_action,
4311 "-action reboot=reset|shutdown\n"
4312 " action when guest reboots [default=reset]\n"
4313 "-action shutdown=poweroff|pause\n"
4314 " action when guest shuts down [default=poweroff]\n"
4315 "-action panic=pause|shutdown|exit-failure|none\n"
4316 " action when guest panics [default=shutdown]\n"
4317 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
4318 " action when watchdog fires [default=reset]\n",
4319 QEMU_ARCH_ALL)
4320 SRST
4321 ``-action event=action``
4322 The action parameter serves to modify QEMU's default behavior when
4323 certain guest events occur. It provides a generic method for specifying the
4324 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown``
4325 parameters.
4327 Examples:
4329 ``-action panic=none``
4330 ``-action reboot=shutdown,shutdown=pause``
4331 ``-watchdog i6300esb -action watchdog=pause``
4333 ERST
4335 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
4336 "-loadvm [tag|id]\n" \
4337 " start right away with a saved state (loadvm in monitor)\n",
4338 QEMU_ARCH_ALL)
4339 SRST
4340 ``-loadvm file``
4341 Start right away with a saved state (``loadvm`` in monitor)
4342 ERST
4344 #ifndef _WIN32
4345 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
4346 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
4347 #endif
4348 SRST
4349 ``-daemonize``
4350 Daemonize the QEMU process after initialization. QEMU will not
4351 detach from standard IO until it is ready to receive connections on
4352 any of its devices. This option is a useful way for external
4353 programs to launch QEMU without having to cope with initialization
4354 race conditions.
4355 ERST
4357 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
4358 "-option-rom rom load a file, rom, into the option ROM space\n",
4359 QEMU_ARCH_ALL)
4360 SRST
4361 ``-option-rom file``
4362 Load the contents of file as an option ROM. This option is useful to
4363 load things like EtherBoot.
4364 ERST
4366 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
4367 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
4368 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
4369 QEMU_ARCH_ALL)
4371 SRST
4372 ``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]``
4373 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at
4374 the current UTC or local time, respectively. ``localtime`` is
4375 required for correct date in MS-DOS or Windows. To start at a
4376 specific point in time, provide datetime in the format
4377 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC.
4379 By default the RTC is driven by the host system time. This allows
4380 using of the RTC as accurate reference clock inside the guest,
4381 specifically if the host time is smoothly following an accurate
4382 external reference clock, e.g. via NTP. If you want to isolate the
4383 guest time from the host, you can set ``clock`` to ``rt`` instead,
4384 which provides a host monotonic clock if host support it. To even
4385 prevent the RTC from progressing during suspension, you can set
4386 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is
4387 recommended especially in icount mode in order to preserve
4388 determinism; however, note that in icount mode the speed of the
4389 virtual clock is variable and can in general differ from the host
4390 clock.
4392 Enable ``driftfix`` (i386 targets only) if you experience time drift
4393 problems, specifically with Windows' ACPI HAL. This option will try
4394 to figure out how many timer interrupts were not processed by the
4395 Windows guest and will re-inject them.
4396 ERST
4398 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
4399 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \
4400 " enable virtual instruction counter with 2^N clock ticks per\n" \
4401 " instruction, enable aligning the host and virtual clocks\n" \
4402 " or disable real time cpu sleeping, and optionally enable\n" \
4403 " record-and-replay mode\n", QEMU_ARCH_ALL)
4404 SRST
4405 ``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]``
4406 Enable virtual instruction counter. The virtual cpu will execute one
4407 instruction every 2^N ns of virtual time. If ``auto`` is specified
4408 then the virtual cpu speed will be automatically adjusted to keep
4409 virtual time within a few seconds of real time.
4411 Note that while this option can give deterministic behavior, it does
4412 not provide cycle accurate emulation. Modern CPUs contain
4413 superscalar out of order cores with complex cache hierarchies. The
4414 number of instructions executed often has little or no correlation
4415 with actual performance.
4417 When the virtual cpu is sleeping, the virtual time will advance at
4418 default speed unless ``sleep=on`` is specified. With
4419 ``sleep=on``, the virtual time will jump to the next timer
4420 deadline instantly whenever the virtual cpu goes to sleep mode and
4421 will not advance if no timer is enabled. This behavior gives
4422 deterministic execution times from the guest point of view.
4423 The default if icount is enabled is ``sleep=off``.
4424 ``sleep=on`` cannot be used together with either ``shift=auto``
4425 or ``align=on``.
4427 ``align=on`` will activate the delay algorithm which will try to
4428 synchronise the host clock and the virtual clock. The goal is to
4429 have a guest running at the real frequency imposed by the shift
4430 option. Whenever the guest clock is behind the host clock and if
4431 ``align=on`` is specified then we print a message to the user to
4432 inform about the delay. Currently this option does not work when
4433 ``shift`` is ``auto``. Note: The sync algorithm will work for those
4434 shift values for which the guest clock runs ahead of the host clock.
4435 Typically this happens when the shift value is high (how high
4436 depends on the host machine). The default if icount is enabled
4437 is ``align=off``.
4439 When the ``rr`` option is specified deterministic record/replay is
4440 enabled. The ``rrfile=`` option must also be provided to
4441 specify the path to the replay log. In record mode data is written
4442 to this file, and in replay mode it is read back.
4443 If the ``rrsnapshot`` option is given then it specifies a VM snapshot
4444 name. In record mode, a new VM snapshot with the given name is created
4445 at the start of execution recording. In replay mode this option
4446 specifies the snapshot name used to load the initial VM state.
4447 ERST
4449 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
4450 "-watchdog model\n" \
4451 " enable virtual hardware watchdog [default=none]\n",
4452 QEMU_ARCH_ALL)
4453 SRST
4454 ``-watchdog model``
4455 Create a virtual hardware watchdog device. Once enabled (by a guest
4456 action), the watchdog must be periodically polled by an agent inside
4457 the guest or else the guest will be restarted. Choose a model for
4458 which your guest has drivers.
4460 The model is the model of hardware watchdog to emulate. Use
4461 ``-watchdog help`` to list available hardware models. Only one
4462 watchdog can be enabled for a guest.
4464 The following models may be available:
4466 ``ib700``
4467 iBASE 700 is a very simple ISA watchdog with a single timer.
4469 ``i6300esb``
4470 Intel 6300ESB I/O controller hub is a much more featureful
4471 PCI-based dual-timer watchdog.
4473 ``diag288``
4474 A virtual watchdog for s390x backed by the diagnose 288
4475 hypercall (currently KVM only).
4476 ERST
4478 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
4479 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
4480 " action when watchdog fires [default=reset]\n",
4481 QEMU_ARCH_ALL)
4482 SRST
4483 ``-watchdog-action action``
4484 The action controls what QEMU will do when the watchdog timer
4485 expires. The default is ``reset`` (forcefully reset the guest).
4486 Other possible actions are: ``shutdown`` (attempt to gracefully
4487 shutdown the guest), ``poweroff`` (forcefully poweroff the guest),
4488 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the
4489 guest), ``debug`` (print a debug message and continue), or ``none``
4490 (do nothing).
4492 Note that the ``shutdown`` action requires that the guest responds
4493 to ACPI signals, which it may not be able to do in the sort of
4494 situations where the watchdog would have expired, and thus
4495 ``-watchdog-action shutdown`` is not recommended for production use.
4497 Examples:
4499 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700``
4501 ERST
4503 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
4504 "-echr chr set terminal escape character instead of ctrl-a\n",
4505 QEMU_ARCH_ALL)
4506 SRST
4507 ``-echr numeric_ascii_value``
4508 Change the escape character used for switching to the monitor when
4509 using monitor and serial sharing. The default is ``0x01`` when using
4510 the ``-nographic`` option. ``0x01`` is equal to pressing
4511 ``Control-a``. You can select a different character from the ascii
4512 control keys where 1 through 26 map to Control-a through Control-z.
4513 For instance you could use the either of the following to change the
4514 escape character to Control-t.
4516 ``-echr 0x14``; \ ``-echr 20``
4518 ERST
4520 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4521 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
4522 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \
4523 "-incoming unix:socketpath\n" \
4524 " prepare for incoming migration, listen on\n" \
4525 " specified protocol and socket address\n" \
4526 "-incoming fd:fd\n" \
4527 "-incoming exec:cmdline\n" \
4528 " accept incoming migration on given file descriptor\n" \
4529 " or from given external command\n" \
4530 "-incoming defer\n" \
4531 " wait for the URI to be specified via migrate_incoming\n",
4532 QEMU_ARCH_ALL)
4533 SRST
4534 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
4536 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
4537 Prepare for incoming migration, listen on a given tcp port.
4539 ``-incoming unix:socketpath``
4540 Prepare for incoming migration, listen on a given unix socket.
4542 ``-incoming fd:fd``
4543 Accept incoming migration from a given filedescriptor.
4545 ``-incoming exec:cmdline``
4546 Accept incoming migration as an output from specified external
4547 command.
4549 ``-incoming defer``
4550 Wait for the URI to be specified via migrate\_incoming. The monitor
4551 can be used to change settings (such as migration parameters) prior
4552 to issuing the migrate\_incoming to allow the migration to begin.
4553 ERST
4555 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4556 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4557 SRST
4558 ``-only-migratable``
4559 Only allow migratable devices. Devices will not be allowed to enter
4560 an unmigratable state.
4561 ERST
4563 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4564 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4565 SRST
4566 ``-nodefaults``
4567 Don't create default devices. Normally, QEMU sets the default
4568 devices like serial port, parallel port, virtual console, monitor
4569 device, VGA adapter, floppy and CD-ROM drive and others. The
4570 ``-nodefaults`` option will disable all those default devices.
4571 ERST
4573 #ifndef _WIN32
4574 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4575 "-chroot dir chroot to dir just before starting the VM\n",
4576 QEMU_ARCH_ALL)
4577 #endif
4578 SRST
4579 ``-chroot dir``
4580 Immediately before starting guest execution, chroot to the specified
4581 directory. Especially useful in combination with -runas.
4582 ERST
4584 #ifndef _WIN32
4585 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4586 "-runas user change to user id user just before starting the VM\n" \
4587 " user can be numeric uid:gid instead\n",
4588 QEMU_ARCH_ALL)
4589 #endif
4590 SRST
4591 ``-runas user``
4592 Immediately before starting guest execution, drop root privileges,
4593 switching to the specified user.
4594 ERST
4596 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4597 "-prom-env variable=value\n"
4598 " set OpenBIOS nvram variables\n",
4599 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4600 SRST
4601 ``-prom-env variable=value``
4602 Set OpenBIOS nvram variable to given value (PPC, SPARC only).
4606 qemu-system-sparc -prom-env 'auto-boot?=false' \
4607 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
4611 qemu-system-ppc -prom-env 'auto-boot?=false' \
4612 -prom-env 'boot-device=hd:2,\yaboot' \
4613 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
4614 ERST
4615 DEF("semihosting", 0, QEMU_OPTION_semihosting,
4616 "-semihosting semihosting mode\n",
4617 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4618 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4619 SRST
4620 ``-semihosting``
4621 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only).
4623 Note that this allows guest direct access to the host filesystem, so
4624 should only be used with a trusted guest OS.
4626 See the -semihosting-config option documentation for further
4627 information about the facilities this enables.
4628 ERST
4629 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4630 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \
4631 " semihosting configuration\n",
4632 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4633 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4634 SRST
4635 ``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]``
4636 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V
4637 only).
4639 Note that this allows guest direct access to the host filesystem, so
4640 should only be used with a trusted guest OS.
4642 On Arm this implements the standard semihosting API, version 2.0.
4644 On M68K this implements the "ColdFire GDB" interface used by
4645 libgloss.
4647 Xtensa semihosting provides basic file IO calls, such as
4648 open/read/write/seek/select. Tensilica baremetal libc for ISS and
4649 linux platform "sim" use this interface.
4651 On RISC-V this implements the standard semihosting API, version 0.2.
4653 ``target=native|gdb|auto``
4654 Defines where the semihosting calls will be addressed, to QEMU
4655 (``native``) or to GDB (``gdb``). The default is ``auto``, which
4656 means ``gdb`` during debug sessions and ``native`` otherwise.
4658 ``chardev=str1``
4659 Send the output to a chardev backend output for native or auto
4660 output when not in gdb
4662 ``userspace=on|off``
4663 Allows code running in guest userspace to access the semihosting
4664 interface. The default is that only privileged guest code can
4665 make semihosting calls. Note that setting ``userspace=on`` should
4666 only be used if all guest code is trusted (for example, in
4667 bare-metal test case code).
4669 ``arg=str1,arg=str2,...``
4670 Allows the user to pass input arguments, and can be used
4671 multiple times to build up a list. The old-style
4672 ``-kernel``/``-append`` method of passing a command line is
4673 still supported for backward compatibility. If both the
4674 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are
4675 specified, the former is passed to semihosting as it always
4676 takes precedence.
4677 ERST
4678 DEF("old-param", 0, QEMU_OPTION_old_param,
4679 "-old-param old param mode\n", QEMU_ARCH_ARM)
4680 SRST
4681 ``-old-param``
4682 Old param mode (ARM only).
4683 ERST
4685 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4686 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4687 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4688 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4689 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4690 " by the kernel, but typically no longer used by modern\n" \
4691 " C library implementations.\n" \
4692 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \
4693 " to elevate privileges using set*uid|gid system calls.\n" \
4694 " The value 'children' will deny set*uid|gid system calls for\n" \
4695 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4696 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4697 " blocking *fork and execve\n" \
4698 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4699 QEMU_ARCH_ALL)
4700 SRST
4701 ``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]``
4702 Enable Seccomp mode 2 system call filter. 'on' will enable syscall
4703 filtering and 'off' will disable it. The default is 'off'.
4705 ``obsolete=string``
4706 Enable Obsolete system calls
4708 ``elevateprivileges=string``
4709 Disable set\*uid\|gid system calls
4711 ``spawn=string``
4712 Disable \*fork and execve
4714 ``resourcecontrol=string``
4715 Disable process affinity and schedular priority
4716 ERST
4718 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4719 "-readconfig <file>\n"
4720 " read config file\n", QEMU_ARCH_ALL)
4721 SRST
4722 ``-readconfig file``
4723 Read device configuration from file. This approach is useful when
4724 you want to spawn QEMU process with many command line options but
4725 you don't want to exceed the command line character limit.
4726 ERST
4728 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4729 "-no-user-config\n"
4730 " do not load default user-provided config files at startup\n",
4731 QEMU_ARCH_ALL)
4732 SRST
4733 ``-no-user-config``
4734 The ``-no-user-config`` option makes QEMU not load any of the
4735 user-provided config files on sysconfdir.
4736 ERST
4738 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4739 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4740 " specify tracing options\n",
4741 QEMU_ARCH_ALL)
4742 SRST
4743 ``-trace [[enable=]pattern][,events=file][,file=file]``
4744 .. include:: ../qemu-option-trace.rst.inc
4746 ERST
4747 DEF("plugin", HAS_ARG, QEMU_OPTION_plugin,
4748 "-plugin [file=]<file>[,<argname>=<argvalue>]\n"
4749 " load a plugin\n",
4750 QEMU_ARCH_ALL)
4751 SRST
4752 ``-plugin file=file[,argname=argvalue]``
4753 Load a plugin.
4755 ``file=file``
4756 Load the given plugin from a shared library file.
4758 ``argname=argvalue``
4759 Argument passed to the plugin. (Can be given multiple times.)
4760 ERST
4762 HXCOMM Internal use
4763 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4764 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4766 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4767 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
4768 " control error message format\n"
4769 " timestamp=on enables timestamps (default: off)\n"
4770 " guest-name=on enables guest name prefix but only if\n"
4771 " -name guest option is set (default: off)\n",
4772 QEMU_ARCH_ALL)
4773 SRST
4774 ``-msg [timestamp[=on|off]][,guest-name[=on|off]]``
4775 Control error message format.
4777 ``timestamp=on|off``
4778 Prefix messages with a timestamp. Default is off.
4780 ``guest-name=on|off``
4781 Prefix messages with guest name but only if -name guest option is set
4782 otherwise the option is ignored. Default is off.
4783 ERST
4785 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4786 "-dump-vmstate <file>\n"
4787 " Output vmstate information in JSON format to file.\n"
4788 " Use the scripts/vmstate-static-checker.py file to\n"
4789 " check for possible regressions in migration code\n"
4790 " by comparing two such vmstate dumps.\n",
4791 QEMU_ARCH_ALL)
4792 SRST
4793 ``-dump-vmstate file``
4794 Dump json-encoded vmstate information for current machine type to
4795 file in file
4796 ERST
4798 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4799 "-enable-sync-profile\n"
4800 " enable synchronization profiling\n",
4801 QEMU_ARCH_ALL)
4802 SRST
4803 ``-enable-sync-profile``
4804 Enable synchronization profiling.
4805 ERST
4807 DEFHEADING()
4809 DEFHEADING(Generic object creation:)
4811 DEF("object", HAS_ARG, QEMU_OPTION_object,
4812 "-object TYPENAME[,PROP1=VALUE1,...]\n"
4813 " create a new object of type TYPENAME setting properties\n"
4814 " in the order they are specified. Note that the 'id'\n"
4815 " property must be set. These objects are placed in the\n"
4816 " '/objects' path.\n",
4817 QEMU_ARCH_ALL)
4818 SRST
4819 ``-object typename[,prop1=value1,...]``
4820 Create a new object of type typename setting properties in the order
4821 they are specified. Note that the 'id' property must be set. These
4822 objects are placed in the '/objects' path.
4824 ``-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,readonly=on|off``
4825 Creates a memory file backend object, which can be used to back
4826 the guest RAM with huge pages.
4828 The ``id`` parameter is a unique ID that will be used to
4829 reference this memory region in other parameters, e.g. ``-numa``,
4830 ``-device nvdimm``, etc.
4832 The ``size`` option provides the size of the memory region, and
4833 accepts common suffixes, e.g. ``500M``.
4835 The ``mem-path`` provides the path to either a shared memory or
4836 huge page filesystem mount.
4838 The ``share`` boolean option determines whether the memory
4839 region is marked as private to QEMU, or shared. The latter
4840 allows a co-operating external process to access the QEMU memory
4841 region.
4843 The ``share`` is also required for pvrdma devices due to
4844 limitations in the RDMA API provided by Linux.
4846 Setting share=on might affect the ability to configure NUMA
4847 bindings for the memory backend under some circumstances, see
4848 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel
4849 source tree for additional details.
4851 Setting the ``discard-data`` boolean option to on indicates that
4852 file contents can be destroyed when QEMU exits, to avoid
4853 unnecessarily flushing data to the backing file. Note that
4854 ``discard-data`` is only an optimization, and QEMU might not
4855 discard file contents if it aborts unexpectedly or is terminated
4856 using SIGKILL.
4858 The ``merge`` boolean option enables memory merge, also known as
4859 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider
4860 the pages for memory deduplication.
4862 Setting the ``dump`` boolean option to off excludes the memory
4863 from core dumps. This feature is also known as MADV\_DONTDUMP.
4865 The ``prealloc`` boolean option enables memory preallocation.
4867 The ``host-nodes`` option binds the memory range to a list of
4868 NUMA host nodes.
4870 The ``policy`` option sets the NUMA policy to one of the
4871 following values:
4873 ``default``
4874 default host policy
4876 ``preferred``
4877 prefer the given host node list for allocation
4879 ``bind``
4880 restrict memory allocation to the given host node list
4882 ``interleave``
4883 interleave memory allocations across the given host node
4884 list
4886 The ``align`` option specifies the base address alignment when
4887 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg
4888 ``2M``. Some backend store specified by ``mem-path`` requires an
4889 alignment different than the default one used by QEMU, eg the
4890 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4891 such cases, users can specify the required alignment via this
4892 option.
4894 The ``pmem`` option specifies whether the backing file specified
4895 by ``mem-path`` is in host persistent memory that can be
4896 accessed using the SNIA NVM programming model (e.g. Intel
4897 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary
4898 operations to guarantee the persistence of its own writes to
4899 ``mem-path`` (e.g. in vNVDIMM label emulation and live
4900 migration). Also, we will map the backend-file with MAP\_SYNC
4901 flag, which ensures the file metadata is in sync for
4902 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC
4903 requires support from both the host kernel (since Linux kernel
4904 4.15) and the filesystem of ``mem-path`` mounted with DAX
4905 option.
4907 The ``readonly`` option specifies whether the backing file is opened
4908 read-only or read-write (default).
4910 ``-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``
4911 Creates a memory backend object, which can be used to back the
4912 guest RAM. Memory backend objects offer more control than the
4913 ``-m`` option that is traditionally used to define guest RAM.
4914 Please refer to ``memory-backend-file`` for a description of the
4915 options.
4917 ``-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``
4918 Creates an anonymous memory file backend object, which allows
4919 QEMU to share the memory with an external process (e.g. when
4920 using vhost-user). The memory is allocated with memfd and
4921 optional sealing. (Linux only)
4923 The ``seal`` option creates a sealed-file, that will block
4924 further resizing the memory ('on' by default).
4926 The ``hugetlb`` option specify the file to be created resides in
4927 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction
4928 with the ``hugetlb`` option, the ``hugetlbsize`` option specify
4929 the hugetlb page size on systems that support multiple hugetlb
4930 page sizes (it must be a power of 2 value supported by the
4931 system).
4933 In some versions of Linux, the ``hugetlb`` option is
4934 incompatible with the ``seal`` option (requires at least Linux
4935 4.16).
4937 Please refer to ``memory-backend-file`` for a description of the
4938 other options.
4940 The ``share`` boolean option is on by default with memfd.
4942 ``-object rng-builtin,id=id``
4943 Creates a random number generator backend which obtains entropy
4944 from QEMU builtin functions. The ``id`` parameter is a unique ID
4945 that will be used to reference this entropy backend from the
4946 ``virtio-rng`` device. By default, the ``virtio-rng`` device
4947 uses this RNG backend.
4949 ``-object rng-random,id=id,filename=/dev/random``
4950 Creates a random number generator backend which obtains entropy
4951 from a device on the host. The ``id`` parameter is a unique ID
4952 that will be used to reference this entropy backend from the
4953 ``virtio-rng`` device. The ``filename`` parameter specifies
4954 which file to obtain entropy from and if omitted defaults to
4955 ``/dev/urandom``.
4957 ``-object rng-egd,id=id,chardev=chardevid``
4958 Creates a random number generator backend which obtains entropy
4959 from an external daemon running on the host. The ``id``
4960 parameter is a unique ID that will be used to reference this
4961 entropy backend from the ``virtio-rng`` device. The ``chardev``
4962 parameter is the unique ID of a character device backend that
4963 provides the connection to the RNG daemon.
4965 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off``
4966 Creates a TLS anonymous credentials object, which can be used to
4967 provide TLS support on network backends. The ``id`` parameter is
4968 a unique ID which network backends will use to access the
4969 credentials. The ``endpoint`` is either ``server`` or ``client``
4970 depending on whether the QEMU network backend that uses the
4971 credentials will be acting as a client or as a server. If
4972 ``verify-peer`` is enabled (the default) then once the handshake
4973 is completed, the peer credentials will be verified, though this
4974 is a no-op for anonymous credentials.
4976 The dir parameter tells QEMU where to find the credential files.
4977 For server endpoints, this directory may contain a file
4978 dh-params.pem providing diffie-hellman parameters to use for the
4979 TLS server. If the file is missing, QEMU will generate a set of
4980 DH parameters at startup. This is a computationally expensive
4981 operation that consumes random pool entropy, so it is
4982 recommended that a persistent set of parameters be generated
4983 upfront and saved.
4985 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]``
4986 Creates a TLS Pre-Shared Keys (PSK) credentials object, which
4987 can be used to provide TLS support on network backends. The
4988 ``id`` parameter is a unique ID which network backends will use
4989 to access the credentials. The ``endpoint`` is either ``server``
4990 or ``client`` depending on whether the QEMU network backend that
4991 uses the credentials will be acting as a client or as a server.
4992 For clients only, ``username`` is the username which will be
4993 sent to the server. If omitted it defaults to "qemu".
4995 The dir parameter tells QEMU where to find the keys file. It is
4996 called "dir/keys.psk" and contains "username:key" pairs. This
4997 file can most easily be created using the GnuTLS ``psktool``
4998 program.
5000 For server endpoints, dir may also contain a file dh-params.pem
5001 providing diffie-hellman parameters to use for the TLS server.
5002 If the file is missing, QEMU will generate a set of DH
5003 parameters at startup. This is a computationally expensive
5004 operation that consumes random pool entropy, so it is
5005 recommended that a persistent set of parameters be generated up
5006 front and saved.
5008 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id``
5009 Creates a TLS anonymous credentials object, which can be used to
5010 provide TLS support on network backends. The ``id`` parameter is
5011 a unique ID which network backends will use to access the
5012 credentials. The ``endpoint`` is either ``server`` or ``client``
5013 depending on whether the QEMU network backend that uses the
5014 credentials will be acting as a client or as a server. If
5015 ``verify-peer`` is enabled (the default) then once the handshake
5016 is completed, the peer credentials will be verified. With x509
5017 certificates, this implies that the clients must be provided
5018 with valid client certificates too.
5020 The dir parameter tells QEMU where to find the credential files.
5021 For server endpoints, this directory may contain a file
5022 dh-params.pem providing diffie-hellman parameters to use for the
5023 TLS server. If the file is missing, QEMU will generate a set of
5024 DH parameters at startup. This is a computationally expensive
5025 operation that consumes random pool entropy, so it is
5026 recommended that a persistent set of parameters be generated
5027 upfront and saved.
5029 For x509 certificate credentials the directory will contain
5030 further files providing the x509 certificates. The certificates
5031 must be stored in PEM format, in filenames ca-cert.pem,
5032 ca-crl.pem (optional), server-cert.pem (only servers),
5033 server-key.pem (only servers), client-cert.pem (only clients),
5034 and client-key.pem (only clients).
5036 For the server-key.pem and client-key.pem files which contain
5037 sensitive private keys, it is possible to use an encrypted
5038 version by providing the passwordid parameter. This provides the
5039 ID of a previously created ``secret`` object containing the
5040 password for decryption.
5042 The priority parameter allows to override the global default
5043 priority used by gnutls. This can be useful if the system
5044 administrator needs to use a weaker set of crypto priorities for
5045 QEMU without potentially forcing the weakness onto all
5046 applications. Or conversely if one wants wants a stronger
5047 default for QEMU than for all other applications, they can do
5048 this through this parameter. Its format is a gnutls priority
5049 string as described at
5050 https://gnutls.org/manual/html_node/Priority-Strings.html.
5052 ``-object tls-cipher-suites,id=id,priority=priority``
5053 Creates a TLS cipher suites object, which can be used to control
5054 the TLS cipher/protocol algorithms that applications are permitted
5055 to use.
5057 The ``id`` parameter is a unique ID which frontends will use to
5058 access the ordered list of permitted TLS cipher suites from the
5059 host.
5061 The ``priority`` parameter allows to override the global default
5062 priority used by gnutls. This can be useful if the system
5063 administrator needs to use a weaker set of crypto priorities for
5064 QEMU without potentially forcing the weakness onto all
5065 applications. Or conversely if one wants wants a stronger
5066 default for QEMU than for all other applications, they can do
5067 this through this parameter. Its format is a gnutls priority
5068 string as described at
5069 https://gnutls.org/manual/html_node/Priority-Strings.html.
5071 An example of use of this object is to control UEFI HTTPS Boot.
5072 The tls-cipher-suites object exposes the ordered list of permitted
5073 TLS cipher suites from the host side to the guest firmware, via
5074 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER
5075 objects. The firmware uses the IANA_TLS_CIPHER array for configuring
5076 guest-side TLS.
5078 In the following example, the priority at which the host-side policy
5079 is retrieved is given by the ``priority`` property.
5080 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to
5081 refer to /etc/crypto-policies/back-ends/gnutls.config.
5083 .. parsed-literal::
5085 # |qemu_system| \\
5086 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\
5087 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
5089 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
5090 Interval t can't be 0, this filter batches the packet delivery:
5091 all packets arriving in a given interval on netdev netdevid are
5092 delayed until the end of the interval. Interval is in
5093 microseconds. ``status`` is optional that indicate whether the
5094 netfilter is on (enabled) or off (disabled), the default status
5095 for netfilter will be 'on'.
5097 queue all\|rx\|tx is an option that can be applied to any
5098 netfilter.
5100 ``all``: the filter is attached both to the receive and the
5101 transmit queue of the netdev (default).
5103 ``rx``: the filter is attached to the receive queue of the
5104 netdev, where it will receive packets sent to the netdev.
5106 ``tx``: the filter is attached to the transmit queue of the
5107 netdev, where it will receive packets sent by the netdev.
5109 position head\|tail\|id=<id> is an option to specify where the
5110 filter should be inserted in the filter list. It can be applied
5111 to any netfilter.
5113 ``head``: the filter is inserted at the head of the filter list,
5114 before any existing filters.
5116 ``tail``: the filter is inserted at the tail of the filter list,
5117 behind any existing filters (default).
5119 ``id=<id>``: the filter is inserted before or behind the filter
5120 specified by <id>, see the insert option below.
5122 insert behind\|before is an option to specify where to insert
5123 the new filter relative to the one specified with
5124 position=id=<id>. It can be applied to any netfilter.
5126 ``before``: insert before the specified filter.
5128 ``behind``: insert behind the specified filter (default).
5130 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5131 filter-mirror on netdev netdevid,mirror net packet to
5132 chardevchardevid, if it has the vnet\_hdr\_support flag,
5133 filter-mirror will mirror packet with vnet\_hdr\_len.
5135 ``-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]``
5136 filter-redirector on netdev netdevid,redirect filter's net
5137 packet to chardev chardevid,and redirect indev's packet to
5138 filter.if it has the vnet\_hdr\_support flag, filter-redirector
5139 will redirect packet with vnet\_hdr\_len. Create a
5140 filter-redirector we need to differ outdev id from indev id, id
5141 can not be the same. we can just use indev or outdev, but at
5142 least one of indev or outdev need to be specified.
5144 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5145 Filter-rewriter is a part of COLO project.It will rewrite tcp
5146 packet to secondary from primary to keep secondary tcp
5147 connection,and rewrite tcp packet to primary from secondary make
5148 tcp packet can be handled by client.if it has the
5149 vnet\_hdr\_support flag, we can parse packet with vnet header.
5151 usage: colo secondary: -object
5152 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object
5153 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object
5154 filter-rewriter,id=rew0,netdev=hn0,queue=all
5156 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]``
5157 Dump the network traffic on netdev dev to the file specified by
5158 filename. At most len bytes (64k by default) per packet are
5159 stored. The file format is libpcap, so it can be analyzed with
5160 tools such as tcpdump or Wireshark.
5162 ``-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}]``
5163 Colo-compare gets packet from primary\_in chardevid and
5164 secondary\_in, then compare whether the payload of primary packet
5165 and secondary packet are the same. If same, it will output
5166 primary packet to out\_dev, else it will notify COLO-framework to do
5167 checkpoint and send primary packet to out\_dev. In order to
5168 improve efficiency, we need to put the task of comparison in
5169 another iothread. If it has the vnet\_hdr\_support flag,
5170 colo compare will send/recv packet with vnet\_hdr\_len.
5171 The compare\_timeout=@var{ms} determines the maximum time of the
5172 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms}
5173 is to set the period of scanning expired primary node network packets.
5174 The max\_queue\_size=@var{size} is to set the max compare queue
5175 size depend on user environment.
5176 If user want to use Xen COLO, need to add the notify\_dev to
5177 notify Xen colo-frame to do checkpoint.
5179 COLO-compare must be used with the help of filter-mirror,
5180 filter-redirector and filter-rewriter.
5184 KVM COLO
5186 primary:
5187 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5188 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5189 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5190 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5191 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5192 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5193 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5194 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5195 -object iothread,id=iothread1
5196 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5197 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5198 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5199 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
5201 secondary:
5202 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5203 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5204 -chardev socket,id=red0,host=3.3.3.3,port=9003
5205 -chardev socket,id=red1,host=3.3.3.3,port=9004
5206 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5207 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5210 Xen COLO
5212 primary:
5213 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5214 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5215 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5216 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5217 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5218 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5219 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5220 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5221 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off
5222 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5223 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5224 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5225 -object iothread,id=iothread1
5226 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
5228 secondary:
5229 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5230 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5231 -chardev socket,id=red0,host=3.3.3.3,port=9003
5232 -chardev socket,id=red1,host=3.3.3.3,port=9004
5233 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5234 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5236 If you want to know the detail of above command line, you can
5237 read the colo-compare git log.
5239 ``-object cryptodev-backend-builtin,id=id[,queues=queues]``
5240 Creates a cryptodev backend which executes crypto opreation from
5241 the QEMU cipher APIS. The id parameter is a unique ID that will
5242 be used to reference this cryptodev backend from the
5243 ``virtio-crypto`` device. The queues parameter is optional,
5244 which specify the queue number of cryptodev backend, the default
5245 of queues is 1.
5247 .. parsed-literal::
5249 # |qemu_system| \\
5250 [...] \\
5251 -object cryptodev-backend-builtin,id=cryptodev0 \\
5252 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5253 [...]
5255 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]``
5256 Creates a vhost-user cryptodev backend, backed by a chardev
5257 chardevid. The id parameter is a unique ID that will be used to
5258 reference this cryptodev backend from the ``virtio-crypto``
5259 device. The chardev should be a unix domain socket backed one.
5260 The vhost-user uses a specifically defined protocol to pass
5261 vhost ioctl replacement messages to an application on the other
5262 end of the socket. The queues parameter is optional, which
5263 specify the queue number of cryptodev backend for multiqueue
5264 vhost-user, the default of queues is 1.
5266 .. parsed-literal::
5268 # |qemu_system| \\
5269 [...] \\
5270 -chardev socket,id=chardev0,path=/path/to/socket \\
5271 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\
5272 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5273 [...]
5275 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]``
5277 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]``
5278 Defines a secret to store a password, encryption key, or some
5279 other sensitive data. The sensitive data can either be passed
5280 directly via the data parameter, or indirectly via the file
5281 parameter. Using the data parameter is insecure unless the
5282 sensitive data is encrypted.
5284 The sensitive data can be provided in raw format (the default),
5285 or base64. When encoded as JSON, the raw format only supports
5286 valid UTF-8 characters, so base64 is recommended for sending
5287 binary data. QEMU will convert from which ever format is
5288 provided to the format it needs internally. eg, an RBD password
5289 can be provided in raw format, even though it will be base64
5290 encoded when passed onto the RBD sever.
5292 For added protection, it is possible to encrypt the data
5293 associated with a secret using the AES-256-CBC cipher. Use of
5294 encryption is indicated by providing the keyid and iv
5295 parameters. The keyid parameter provides the ID of a previously
5296 defined secret that contains the AES-256 decryption key. This
5297 key should be 32-bytes long and be base64 encoded. The iv
5298 parameter provides the random initialization vector used for
5299 encryption of this particular secret and should be a base64
5300 encrypted string of the 16-byte IV.
5302 The simplest (insecure) usage is to provide the secret inline
5304 .. parsed-literal::
5306 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw
5308 The simplest secure usage is to provide the secret via a file
5310 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object
5311 secret,id=sec0,file=mypasswd.txt,format=raw
5313 For greater security, AES-256-CBC should be used. To illustrate
5314 usage, consider the openssl command line tool which can encrypt
5315 the data. Note that when encrypting, the plaintext must be
5316 padded to the cipher block size (32 bytes) using the standard
5317 PKCS#5/6 compatible padding algorithm.
5319 First a master key needs to be created in base64 encoding:
5323 # openssl rand -base64 32 > key.b64
5324 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
5326 Each secret to be encrypted needs to have a random
5327 initialization vector generated. These do not need to be kept
5328 secret
5332 # openssl rand -base64 16 > iv.b64
5333 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
5335 The secret to be defined can now be encrypted, in this case
5336 we're telling openssl to base64 encode the result, but it could
5337 be left as raw bytes if desired.
5341 # SECRET=$(printf "letmein" |
5342 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
5344 When launching QEMU, create a master secret pointing to
5345 ``key.b64`` and specify that to be used to decrypt the user
5346 password. Pass the contents of ``iv.b64`` to the second secret
5348 .. parsed-literal::
5350 # |qemu_system| \\
5351 -object secret,id=secmaster0,format=base64,file=key.b64 \\
5352 -object secret,id=sec0,keyid=secmaster0,format=base64,\\
5353 data=$SECRET,iv=$(<iv.b64)
5355 ``-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]``
5356 Create a Secure Encrypted Virtualization (SEV) guest object,
5357 which can be used to provide the guest memory encryption support
5358 on AMD processors.
5360 When memory encryption is enabled, one of the physical address
5361 bit (aka the C-bit) is utilized to mark if a memory page is
5362 protected. The ``cbitpos`` is used to provide the C-bit
5363 position. The C-bit position is Host family dependent hence user
5364 must provide this value. On EPYC, the value should be 47.
5366 When memory encryption is enabled, we loose certain bits in
5367 physical address space. The ``reduced-phys-bits`` is used to
5368 provide the number of bits we loose in physical address space.
5369 Similar to C-bit, the value is Host family dependent. On EPYC,
5370 the value should be 5.
5372 The ``sev-device`` provides the device file to use for
5373 communicating with the SEV firmware running inside AMD Secure
5374 Processor. The default device is '/dev/sev'. If hardware
5375 supports memory encryption then /dev/sev devices are created by
5376 CCP driver.
5378 The ``policy`` provides the guest policy to be enforced by the
5379 SEV firmware and restrict what configuration and operational
5380 commands can be performed on this guest by the hypervisor. The
5381 policy should be provided by the guest owner and is bound to the
5382 guest and cannot be changed throughout the lifetime of the
5383 guest. The default is 0.
5385 If guest ``policy`` allows sharing the key with another SEV
5386 guest then ``handle`` can be use to provide handle of the guest
5387 from which to share the key.
5389 The ``dh-cert-file`` and ``session-file`` provides the guest
5390 owner's Public Diffie-Hillman key defined in SEV spec. The PDH
5391 and session parameters are used for establishing a cryptographic
5392 session with the guest owner to negotiate keys used for
5393 attestation. The file must be encoded in base64.
5395 The ``kernel-hashes`` adds the hashes of given kernel/initrd/
5396 cmdline to a designated guest firmware page for measured Linux
5397 boot with -kernel. The default is off. (Since 6.2)
5399 e.g to launch a SEV guest
5401 .. parsed-literal::
5403 # |qemu_system_x86| \\
5404 ...... \\
5405 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\
5406 -machine ...,memory-encryption=sev0 \\
5407 .....
5409 ``-object authz-simple,id=id,identity=string``
5410 Create an authorization object that will control access to
5411 network services.
5413 The ``identity`` parameter is identifies the user and its format
5414 depends on the network service that authorization object is
5415 associated with. For authorizing based on TLS x509 certificates,
5416 the identity must be the x509 distinguished name. Note that care
5417 must be taken to escape any commas in the distinguished name.
5419 An example authorization object to validate a x509 distinguished
5420 name would look like:
5422 .. parsed-literal::
5424 # |qemu_system| \\
5425 ... \\
5426 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\
5429 Note the use of quotes due to the x509 distinguished name
5430 containing whitespace, and escaping of ','.
5432 ``-object authz-listfile,id=id,filename=path,refresh=on|off``
5433 Create an authorization object that will control access to
5434 network services.
5436 The ``filename`` parameter is the fully qualified path to a file
5437 containing the access control list rules in JSON format.
5439 An example set of rules that match against SASL usernames might
5440 look like:
5445 "rules": [
5446 { "match": "fred", "policy": "allow", "format": "exact" },
5447 { "match": "bob", "policy": "allow", "format": "exact" },
5448 { "match": "danb", "policy": "deny", "format": "glob" },
5449 { "match": "dan*", "policy": "allow", "format": "exact" },
5451 "policy": "deny"
5454 When checking access the object will iterate over all the rules
5455 and the first rule to match will have its ``policy`` value
5456 returned as the result. If no rules match, then the default
5457 ``policy`` value is returned.
5459 The rules can either be an exact string match, or they can use
5460 the simple UNIX glob pattern matching to allow wildcards to be
5461 used.
5463 If ``refresh`` is set to true the file will be monitored and
5464 automatically reloaded whenever its content changes.
5466 As with the ``authz-simple`` object, the format of the identity
5467 strings being matched depends on the network service, but is
5468 usually a TLS x509 distinguished name, or a SASL username.
5470 An example authorization object to validate a SASL username
5471 would look like:
5473 .. parsed-literal::
5475 # |qemu_system| \\
5476 ... \\
5477 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\
5480 ``-object authz-pam,id=id,service=string``
5481 Create an authorization object that will control access to
5482 network services.
5484 The ``service`` parameter provides the name of a PAM service to
5485 use for authorization. It requires that a file
5486 ``/etc/pam.d/service`` exist to provide the configuration for
5487 the ``account`` subsystem.
5489 An example authorization object to validate a TLS x509
5490 distinguished name would look like:
5492 .. parsed-literal::
5494 # |qemu_system| \\
5495 ... \\
5496 -object authz-pam,id=auth0,service=qemu-vnc \\
5499 There would then be a corresponding config file for PAM at
5500 ``/etc/pam.d/qemu-vnc`` that contains:
5504 account requisite pam_listfile.so item=user sense=allow \
5505 file=/etc/qemu/vnc.allow
5507 Finally the ``/etc/qemu/vnc.allow`` file would contain the list
5508 of x509 distingished names that are permitted access
5512 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
5514 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch``
5515 Creates a dedicated event loop thread that devices can be
5516 assigned to. This is known as an IOThread. By default device
5517 emulation happens in vCPU threads or the main event loop thread.
5518 This can become a scalability bottleneck. IOThreads allow device
5519 emulation and I/O to run on other host CPUs.
5521 The ``id`` parameter is a unique ID that will be used to
5522 reference this IOThread from ``-device ...,iothread=id``.
5523 Multiple devices can be assigned to an IOThread. Note that not
5524 all devices support an ``iothread`` parameter.
5526 The ``query-iothreads`` QMP command lists IOThreads and reports
5527 their thread IDs so that the user can configure host CPU
5528 pinning/affinity.
5530 IOThreads use an adaptive polling algorithm to reduce event loop
5531 latency. Instead of entering a blocking system call to monitor
5532 file descriptors and then pay the cost of being woken up when an
5533 event occurs, the polling algorithm spins waiting for events for
5534 a short time. The algorithm's default parameters are suitable
5535 for many cases but can be adjusted based on knowledge of the
5536 workload and/or host device latency.
5538 The ``poll-max-ns`` parameter is the maximum number of
5539 nanoseconds to busy wait for events. Polling can be disabled by
5540 setting this value to 0.
5542 The ``poll-grow`` parameter is the multiplier used to increase
5543 the polling time when the algorithm detects it is missing events
5544 due to not polling long enough.
5546 The ``poll-shrink`` parameter is the divisor used to decrease
5547 the polling time when the algorithm detects it is spending too
5548 long polling without encountering events.
5550 The ``aio-max-batch`` parameter is the maximum number of requests
5551 in a batch for the AIO engine, 0 means that the engine will use
5552 its default.
5554 The IOThread parameters can be modified at run-time using the
5555 ``qom-set`` command (where ``iothread1`` is the IOThread's
5556 ``id``):
5560 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
5561 ERST
5564 HXCOMM This is the last statement. Insert new options before this line!
5566 #undef DEF
5567 #undef DEFHEADING
5568 #undef ARCHHEADING