target/ppc: Remove DisasContext.exception
[qemu/rayw.git] / qemu-options.hx
blobe22fb94d99278795f4076b5ca29762d3b3f27bf6
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 QEMU_ARCH_ALL)
41 SRST
42 ``-machine [type=]name[,prop=value[,...]]``
43 Select the emulated machine by name. Use ``-machine help`` to list
44 available machines.
46 For architectures which aim to support live migration compatibility
47 across releases, each release will introduce a new versioned machine
48 type. For example, the 2.8.0 release introduced machine types
49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures.
51 To allow live migration of guests from QEMU version 2.8.0, to QEMU
52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8"
53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to
54 skip multiple intermediate releases when upgrading, new releases of
55 QEMU will support machine types from many previous versions.
57 Supported machine properties are:
59 ``accel=accels1[:accels2[:...]]``
60 This is used to enable an accelerator. Depending on the target
61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available.
62 By default, tcg is used. If there is more than one accelerator
63 specified, the next one is used if the previous one fails to
64 initialize.
66 ``vmport=on|off|auto``
67 Enables emulation of VMWare IO port, for vmmouse etc. auto says
68 to select the value based on accel. For accel=xen the default is
69 off otherwise the default is on.
71 ``dump-guest-core=on|off``
72 Include guest memory in a core dump. The default is on.
74 ``mem-merge=on|off``
75 Enables or disables memory merge support. This feature, when
76 supported by the host, de-duplicates identical memory pages
77 among VMs instances (enabled by default).
79 ``aes-key-wrap=on|off``
80 Enables or disables AES key wrapping support on s390-ccw hosts.
81 This feature controls whether AES wrapping keys will be created
82 to allow execution of AES cryptographic functions. The default
83 is on.
85 ``dea-key-wrap=on|off``
86 Enables or disables DEA key wrapping support on s390-ccw hosts.
87 This feature controls whether DEA wrapping keys will be created
88 to allow execution of DEA cryptographic functions. The default
89 is on.
91 ``nvdimm=on|off``
92 Enables or disables NVDIMM support. The default is off.
94 ``memory-encryption=``
95 Memory encryption object to use. The default is none.
97 ``hmat=on|off``
98 Enables or disables ACPI Heterogeneous Memory Attribute Table
99 (HMAT) support. The default is off.
101 ``memory-backend='id'``
102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options.
103 Allows to use a memory backend as main RAM.
105 For example:
107 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on
108 -machine memory-backend=pc.ram
109 -m 512M
111 Migration compatibility note:
112 a) as backend id one shall use value of 'default-ram-id', advertised by
113 machine type (available via ``query-machines`` QMP command), if migration
114 to/from old QEMU (<5.0) is expected.
115 b) for machine types 4.0 and older, user shall
116 use ``x-use-canonical-path-for-ramblock-id=off`` backend option
117 if migration to/from old QEMU (<5.0) is expected.
118 For example:
120 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off
121 -machine memory-backend=pc.ram
122 -m 512M
123 ERST
125 HXCOMM Deprecated by -machine
126 DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL)
128 DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
129 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
130 SRST
131 ``-cpu model``
132 Select CPU model (``-cpu help`` for list and additional feature
133 selection)
134 ERST
136 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
137 "-accel [accel=]accelerator[,prop[=value][,...]]\n"
138 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n"
139 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
140 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n"
141 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n"
142 " split-wx=on|off (enable TCG split w^x mapping)\n"
143 " tb-size=n (TCG translation block cache size)\n"
144 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
145 SRST
146 ``-accel name[,prop=value[,...]]``
147 This is used to enable an accelerator. Depending on the target
148 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By
149 default, tcg is used. If there is more than one accelerator
150 specified, the next one is used if the previous one fails to
151 initialize.
153 ``igd-passthru=on|off``
154 When Xen is in use, this option controls whether Intel
155 integrated graphics devices can be passed through to the guest
156 (default=off)
158 ``kernel-irqchip=on|off|split``
159 Controls KVM in-kernel irqchip support. The default is full
160 acceleration of the interrupt controllers. On x86, split irqchip
161 reduces the kernel attack surface, at a performance cost for
162 non-MSI interrupts. Disabling the in-kernel irqchip completely
163 is not recommended except for debugging purposes.
165 ``kvm-shadow-mem=size``
166 Defines the size of the KVM shadow MMU.
168 ``split-wx=on|off``
169 Controls the use of split w^x mapping for the TCG code generation
170 buffer. Some operating systems require this to be enabled, and in
171 such a case this will default on. On other operating systems, this
172 will default off, but one may enable this for testing or debugging.
174 ``tb-size=n``
175 Controls the size (in MiB) of the TCG translation block cache.
177 ``thread=single|multi``
178 Controls number of TCG threads. When the TCG is multi-threaded
179 there will be one thread per vCPU therefore taking advantage of
180 additional host cores. The default is to enable multi-threading
181 where both the back-end and front-ends support it and no
182 incompatible TCG features have been enabled (e.g.
183 icount/replay).
184 ERST
186 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
187 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
188 " set the number of CPUs to 'n' [default=1]\n"
189 " maxcpus= maximum number of total cpus, including\n"
190 " offline CPUs for hotplug, etc\n"
191 " cores= number of CPU cores on one socket (for PC, it's on one die)\n"
192 " threads= number of threads on one CPU core\n"
193 " dies= number of CPU dies on one socket (for PC only)\n"
194 " sockets= number of discrete sockets in the system\n",
195 QEMU_ARCH_ALL)
196 SRST
197 ``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]``
198 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs
199 are supported. On Sparc32 target, Linux limits the number of usable
200 CPUs to 4. For the PC target, the number of cores per die, the
201 number of threads per cores, the number of dies per packages and the
202 total number of sockets can be specified. Missing values will be
203 computed. If any on the three values is given, the total number of
204 CPUs n can be omitted. maxcpus specifies the maximum number of
205 hotpluggable CPUs.
206 ERST
208 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
209 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
210 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
211 "-numa dist,src=source,dst=destination,val=distance\n"
212 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n"
213 "-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"
214 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n",
215 QEMU_ARCH_ALL)
216 SRST
217 ``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
219 ``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
221 ``-numa dist,src=source,dst=destination,val=distance``
223 ``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]``
225 ``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]``
227 ``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]``
228 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA
229 distance from a source node to a destination node. Set the ACPI
230 Heterogeneous Memory Attributes for the given nodes.
232 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and
233 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a
234 contiguous range of CPU indexes (or a single VCPU if lastcpu is
235 omitted). A non-contiguous set of VCPUs can be represented by
236 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is
237 omitted on all nodes, VCPUs are automatically split between them.
239 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a
240 NUMA node:
244 -numa node,cpus=0-2,cpus=5
246 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option
247 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to
248 assign CPU objects to a node using topology layout properties of
249 CPU. The set of properties is machine specific, and depends on used
250 machine type/'\ ``smp``\ ' options. It could be queried with
251 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ '
252 property specifies node to which CPU object will be assigned, it's
253 required for node to be declared with '\ ``node``\ ' option before
254 it's used with '\ ``cpu``\ ' option.
256 For example:
260 -M pc \
261 -smp 1,sockets=2,maxcpus=2 \
262 -numa node,nodeid=0 -numa node,nodeid=1 \
263 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
265 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported
266 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from
267 a given memory backend device to a node. If '\ ``mem``\ ' and
268 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them.
271 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive.
272 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to
273 use it.
275 '\ ``initiator``\ ' is an additional option that points to an
276 initiator NUMA node that has best performance (the lowest latency or
277 largest bandwidth) to this NUMA node. Note that this option can be
278 set only when the machine property 'hmat' is set to 'on'.
280 Following example creates a machine with 2 NUMA nodes, node 0 has
281 CPU. node 1 has only memory, and its initiator is node 0. Note that
282 because node 0 has CPU, by default the initiator of node 0 is itself
283 and must be itself.
287 -machine hmat=on \
288 -m 2G,slots=2,maxmem=4G \
289 -object memory-backend-ram,size=1G,id=m0 \
290 -object memory-backend-ram,size=1G,id=m1 \
291 -numa node,nodeid=0,memdev=m0 \
292 -numa node,nodeid=1,memdev=m1,initiator=0 \
293 -smp 2,sockets=2,maxcpus=2 \
294 -numa cpu,node-id=0,socket-id=0 \
295 -numa cpu,node-id=0,socket-id=1
297 source and destination are NUMA node IDs. distance is the NUMA
298 distance from source to destination. The distance from a node to
299 itself is always 10. If any pair of nodes is given a distance, then
300 all pairs must be given distances. Although, when distances are only
301 given in one direction for each pair of nodes, then the distances in
302 the opposite directions are assumed to be the same. If, however, an
303 asymmetrical pair of distances is given for even one node pair, then
304 all node pairs must be provided distance values for both directions,
305 even when they are symmetrical. When a node is unreachable from
306 another node, set the pair's distance to 255.
308 Note that the -``numa`` option doesn't allocate any of the specified
309 resources, it just assigns existing resources to NUMA nodes. This
310 means that one still has to use the ``-m``, ``-smp`` options to
311 allocate RAM and VCPUs respectively.
313 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth
314 Information between initiator and target NUMA nodes in ACPI
315 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can
316 create memory requests, usually it has one or more processors.
317 Target NUMA node contains addressable memory.
319 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is
320 the memory hierarchy of the target NUMA node: if hierarchy is
321 'memory', the structure represents the memory performance; if
322 hierarchy is 'first-level\|second-level\|third-level', this
323 structure represents aggregated performance of memory side caches
324 for each domain. type of 'data-type' is type of data represented by
325 this structure instance: if 'hierarchy' is 'memory', 'data-type' is
326 'access\|read\|write' latency or 'access\|read\|write' bandwidth of
327 the target memory; if 'hierarchy' is
328 'first-level\|second-level\|third-level', 'data-type' is
329 'access\|read\|write' hit latency or 'access\|read\|write' hit
330 bandwidth of the target memory side cache.
332 lat is latency value in nanoseconds. bw is bandwidth value, the
333 possible value and units are NUM[M\|G\|T], mean that the bandwidth
334 value are NUM byte per second (or MB/s, GB/s or TB/s depending on
335 used suffix). Note that if latency or bandwidth value is 0, means
336 the corresponding latency or bandwidth information is not provided.
338 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory
339 belongs. size is the size of memory side cache in bytes. level is
340 the cache level described in this structure, note that the cache
341 level 0 should not be used with '\ ``hmat-cache``\ ' option.
342 associativity is the cache associativity, the possible value is
343 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy
344 is the write policy. line is the cache Line size in bytes.
346 For example, the following options describe 2 NUMA nodes. Node 0 has
347 2 cpus and a ram, node 1 has only a ram. The processors in node 0
348 access memory in node 0 with access-latency 5 nanoseconds,
349 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access
350 memory in NUMA node 1 with access-latency 10 nanoseconds,
351 access-bandwidth is 100 MB/s. And for memory side cache information,
352 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB,
353 policy is write-back, the cache Line size is 8 bytes:
357 -machine hmat=on \
358 -m 2G \
359 -object memory-backend-ram,size=1G,id=m0 \
360 -object memory-backend-ram,size=1G,id=m1 \
361 -smp 2 \
362 -numa node,nodeid=0,memdev=m0 \
363 -numa node,nodeid=1,memdev=m1,initiator=0 \
364 -numa cpu,node-id=0,socket-id=0 \
365 -numa cpu,node-id=0,socket-id=1 \
366 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \
367 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \
368 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \
369 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \
370 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \
371 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8
372 ERST
374 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
375 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
376 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
377 SRST
378 ``-add-fd fd=fd,set=set[,opaque=opaque]``
379 Add a file descriptor to an fd set. Valid options are:
381 ``fd=fd``
382 This option defines the file descriptor of which a duplicate is
383 added to fd set. The file descriptor cannot be stdin, stdout, or
384 stderr.
386 ``set=set``
387 This option defines the ID of the fd set to add the file
388 descriptor to.
390 ``opaque=opaque``
391 This option defines a free-form string that can be used to
392 describe fd.
394 You can open an image using pre-opened file descriptors from an fd
395 set:
397 .. parsed-literal::
399 |qemu_system| \\
400 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
401 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
402 -drive file=/dev/fdset/2,index=0,media=disk
403 ERST
405 DEF("set", HAS_ARG, QEMU_OPTION_set,
406 "-set group.id.arg=value\n"
407 " set <arg> parameter for item <id> of type <group>\n"
408 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
409 SRST
410 ``-set group.id.arg=value``
411 Set parameter arg for item id of type group
412 ERST
414 DEF("global", HAS_ARG, QEMU_OPTION_global,
415 "-global driver.property=value\n"
416 "-global driver=driver,property=property,value=value\n"
417 " set a global default for a driver property\n",
418 QEMU_ARCH_ALL)
419 SRST
420 ``-global driver.prop=value``
422 ``-global driver=driver,property=property,value=value``
423 Set default value of driver's property prop to value, e.g.:
425 .. parsed-literal::
427 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img
429 In particular, you can use this to set driver properties for devices
430 which are created automatically by the machine model. To create a
431 device which is not created automatically and set properties on it,
432 use -``device``.
434 -global driver.prop=value is shorthand for -global
435 driver=driver,property=prop,value=value. The longhand syntax works
436 even when driver contains a dot.
437 ERST
439 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
440 "-boot [order=drives][,once=drives][,menu=on|off]\n"
441 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
442 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
443 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
444 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
445 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
446 QEMU_ARCH_ALL)
447 SRST
448 ``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]``
449 Specify boot order drives as a string of drive letters. Valid drive
450 letters depend on the target architecture. The x86 PC uses: a, b
451 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p
452 (Etherboot from network adapter 1-4), hard disk boot is the default.
453 To apply a particular boot order only on the first startup, specify
454 it via ``once``. Note that the ``order`` or ``once`` parameter
455 should not be used together with the ``bootindex`` property of
456 devices, since the firmware implementations normally do not support
457 both at the same time.
459 Interactive boot menus/prompts can be enabled via ``menu=on`` as far
460 as firmware/BIOS supports them. The default is non-interactive boot.
462 A splash picture could be passed to bios, enabling user to show it
463 as logo, when option splash=sp\_name is given and menu=on, If
464 firmware/BIOS supports them. Currently Seabios for X86 system
465 support it. limitation: The splash file could be a jpeg file or a
466 BMP file in 24 BPP format(true color). The resolution should be
467 supported by the SVGA mode, so the recommended is 320x240, 640x480,
468 800x640.
470 A timeout could be passed to bios, guest will pause for rb\_timeout
471 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will
472 not reboot, qemu passes '-1' to bios by default. Currently Seabios
473 for X86 system support it.
475 Do strict boot via ``strict=on`` as far as firmware/BIOS supports
476 it. This only effects when boot priority is changed by bootindex
477 options. The default is non-strict boot.
479 .. parsed-literal::
481 # try to boot from network first, then from hard disk
482 |qemu_system_x86| -boot order=nc
483 # boot from CD-ROM first, switch back to default order after reboot
484 |qemu_system_x86| -boot once=d
485 # boot with a splash picture for 5 seconds.
486 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000
488 Note: The legacy format '-boot drives' is still supported but its
489 use is discouraged as it may be removed from future versions.
490 ERST
492 DEF("m", HAS_ARG, QEMU_OPTION_m,
493 "-m [size=]megs[,slots=n,maxmem=size]\n"
494 " configure guest RAM\n"
495 " size: initial amount of guest memory\n"
496 " slots: number of hotplug slots (default: none)\n"
497 " maxmem: maximum amount of guest memory (default: none)\n"
498 "NOTE: Some architectures might enforce a specific granularity\n",
499 QEMU_ARCH_ALL)
500 SRST
501 ``-m [size=]megs[,slots=n,maxmem=size]``
502 Sets guest startup RAM size to megs megabytes. Default is 128 MiB.
503 Optionally, a suffix of "M" or "G" can be used to signify a value in
504 megabytes or gigabytes respectively. Optional pair slots, maxmem
505 could be used to set amount of hotpluggable memory slots and maximum
506 amount of memory. Note that maxmem must be aligned to the page size.
508 For example, the following command-line sets the guest startup RAM
509 size to 1GB, creates 3 slots to hotplug additional memory and sets
510 the maximum memory the guest can reach to 4GB:
512 .. parsed-literal::
514 |qemu_system| -m 1G,slots=3,maxmem=4G
516 If slots and maxmem are not specified, memory hotplug won't be
517 enabled and the guest startup RAM will never increase.
518 ERST
520 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
521 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
522 SRST
523 ``-mem-path path``
524 Allocate guest RAM from a temporarily created file in path.
525 ERST
527 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
528 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
529 QEMU_ARCH_ALL)
530 SRST
531 ``-mem-prealloc``
532 Preallocate memory when using -mem-path.
533 ERST
535 DEF("k", HAS_ARG, QEMU_OPTION_k,
536 "-k language use keyboard layout (for example 'fr' for French)\n",
537 QEMU_ARCH_ALL)
538 SRST
539 ``-k language``
540 Use keyboard layout language (for example ``fr`` for French). This
541 option is only needed where it is not easy to get raw PC keycodes
542 (e.g. on Macs, with some X11 servers or with a VNC or curses
543 display). You don't normally need to use it on PC/Linux or
544 PC/Windows hosts.
546 The available layouts are:
550 ar de-ch es fo fr-ca hu ja mk no pt-br sv
551 da en-gb et fr fr-ch is lt nl pl ru th
552 de en-us fi fr-be hr it lv nl-be pt sl tr
554 The default is ``en-us``.
555 ERST
558 HXCOMM Deprecated by -audiodev
559 DEF("audio-help", 0, QEMU_OPTION_audio_help,
560 "-audio-help show -audiodev equivalent of the currently specified audio settings\n",
561 QEMU_ARCH_ALL)
562 SRST
563 ``-audio-help``
564 Will show the -audiodev equivalent of the currently specified
565 (deprecated) environment variables.
566 ERST
568 DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
569 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
570 " specifies the audio backend to use\n"
571 " id= identifier of the backend\n"
572 " timer-period= timer period in microseconds\n"
573 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n"
574 " in|out.fixed-settings= use fixed settings for host audio\n"
575 " in|out.frequency= frequency to use with fixed settings\n"
576 " in|out.channels= number of channels to use with fixed settings\n"
577 " in|out.format= sample format to use with fixed settings\n"
578 " valid values: s8, s16, s32, u8, u16, u32, f32\n"
579 " in|out.voices= number of voices to use\n"
580 " in|out.buffer-length= length of buffer in microseconds\n"
581 "-audiodev none,id=id,[,prop[=value][,...]]\n"
582 " dummy driver that discards all output\n"
583 #ifdef CONFIG_AUDIO_ALSA
584 "-audiodev alsa,id=id[,prop[=value][,...]]\n"
585 " in|out.dev= name of the audio device to use\n"
586 " in|out.period-length= length of period in microseconds\n"
587 " in|out.try-poll= attempt to use poll mode\n"
588 " threshold= threshold (in microseconds) when playback starts\n"
589 #endif
590 #ifdef CONFIG_AUDIO_COREAUDIO
591 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
592 " in|out.buffer-count= number of buffers\n"
593 #endif
594 #ifdef CONFIG_AUDIO_DSOUND
595 "-audiodev dsound,id=id[,prop[=value][,...]]\n"
596 " latency= add extra latency to playback in microseconds\n"
597 #endif
598 #ifdef CONFIG_AUDIO_OSS
599 "-audiodev oss,id=id[,prop[=value][,...]]\n"
600 " in|out.dev= path of the audio device to use\n"
601 " in|out.buffer-count= number of buffers\n"
602 " in|out.try-poll= attempt to use poll mode\n"
603 " try-mmap= try using memory mapped access\n"
604 " exclusive= open device in exclusive mode\n"
605 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
606 #endif
607 #ifdef CONFIG_AUDIO_PA
608 "-audiodev pa,id=id[,prop[=value][,...]]\n"
609 " server= PulseAudio server address\n"
610 " in|out.name= source/sink device name\n"
611 " in|out.latency= desired latency in microseconds\n"
612 #endif
613 #ifdef CONFIG_AUDIO_SDL
614 "-audiodev sdl,id=id[,prop[=value][,...]]\n"
615 " in|out.buffer-count= number of buffers\n"
616 #endif
617 #ifdef CONFIG_SPICE
618 "-audiodev spice,id=id[,prop[=value][,...]]\n"
619 #endif
620 "-audiodev wav,id=id[,prop[=value][,...]]\n"
621 " path= path of wav file to record\n",
622 QEMU_ARCH_ALL)
623 SRST
624 ``-audiodev [driver=]driver,id=id[,prop[=value][,...]]``
625 Adds a new audio backend driver identified by id. There are global
626 and driver specific properties. Some values can be set differently
627 for input and output, they're marked with ``in|out.``. You can set
628 the input's property with ``in.prop`` and the output's property with
629 ``out.prop``. For example:
633 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
634 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
636 NOTE: parameter validation is known to be incomplete, in many cases
637 specifying an invalid option causes QEMU to print an error message
638 and continue emulation without sound.
640 Valid global options are:
642 ``id=identifier``
643 Identifies the audio backend.
645 ``timer-period=period``
646 Sets the timer period used by the audio subsystem in
647 microseconds. Default is 10000 (10 ms).
649 ``in|out.mixing-engine=on|off``
650 Use QEMU's mixing engine to mix all streams inside QEMU and
651 convert audio formats when not supported by the backend. When
652 off, fixed-settings must be off too. Note that disabling this
653 option means that the selected backend must support multiple
654 streams and the audio formats used by the virtual cards,
655 otherwise you'll get no sound. It's not recommended to disable
656 this option unless you want to use 5.1 or 7.1 audio, as mixing
657 engine only supports mono and stereo audio. Default is on.
659 ``in|out.fixed-settings=on|off``
660 Use fixed settings for host audio. When off, it will change
661 based on how the guest opens the sound card. In this case you
662 must not specify frequency, channels or format. Default is on.
664 ``in|out.frequency=frequency``
665 Specify the frequency to use when using fixed-settings. Default
666 is 44100Hz.
668 ``in|out.channels=channels``
669 Specify the number of channels to use when using fixed-settings.
670 Default is 2 (stereo).
672 ``in|out.format=format``
673 Specify the sample format to use when using fixed-settings.
674 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``,
675 ``u32``, ``f32``. Default is ``s16``.
677 ``in|out.voices=voices``
678 Specify the number of voices to use. Default is 1.
680 ``in|out.buffer-length=usecs``
681 Sets the size of the buffer in microseconds.
683 ``-audiodev none,id=id[,prop[=value][,...]]``
684 Creates a dummy backend that discards all outputs. This backend has
685 no backend specific properties.
687 ``-audiodev alsa,id=id[,prop[=value][,...]]``
688 Creates backend using the ALSA. This backend is only available on
689 Linux.
691 ALSA specific options are:
693 ``in|out.dev=device``
694 Specify the ALSA device to use for input and/or output. Default
695 is ``default``.
697 ``in|out.period-length=usecs``
698 Sets the period length in microseconds.
700 ``in|out.try-poll=on|off``
701 Attempt to use poll mode with the device. Default is on.
703 ``threshold=threshold``
704 Threshold (in microseconds) when playback starts. Default is 0.
706 ``-audiodev coreaudio,id=id[,prop[=value][,...]]``
707 Creates a backend using Apple's Core Audio. This backend is only
708 available on Mac OS and only supports playback.
710 Core Audio specific options are:
712 ``in|out.buffer-count=count``
713 Sets the count of the buffers.
715 ``-audiodev dsound,id=id[,prop[=value][,...]]``
716 Creates a backend using Microsoft's DirectSound. This backend is
717 only available on Windows and only supports playback.
719 DirectSound specific options are:
721 ``latency=usecs``
722 Add extra usecs microseconds latency to playback. Default is
723 10000 (10 ms).
725 ``-audiodev oss,id=id[,prop[=value][,...]]``
726 Creates a backend using OSS. This backend is available on most
727 Unix-like systems.
729 OSS specific options are:
731 ``in|out.dev=device``
732 Specify the file name of the OSS device to use. Default is
733 ``/dev/dsp``.
735 ``in|out.buffer-count=count``
736 Sets the count of the buffers.
738 ``in|out.try-poll=on|of``
739 Attempt to use poll mode with the device. Default is on.
741 ``try-mmap=on|off``
742 Try using memory mapped device access. Default is off.
744 ``exclusive=on|off``
745 Open the device in exclusive mode (vmix won't work in this
746 case). Default is off.
748 ``dsp-policy=policy``
749 Sets the timing policy (between 0 and 10, where smaller number
750 means smaller latency but higher CPU usage). Use -1 to use
751 buffer sizes specified by ``buffer`` and ``buffer-count``. This
752 option is ignored if you do not have OSS 4. Default is 5.
754 ``-audiodev pa,id=id[,prop[=value][,...]]``
755 Creates a backend using PulseAudio. This backend is available on
756 most systems.
758 PulseAudio specific options are:
760 ``server=server``
761 Sets the PulseAudio server to connect to.
763 ``in|out.name=sink``
764 Use the specified source/sink for recording/playback.
766 ``in|out.latency=usecs``
767 Desired latency in microseconds. The PulseAudio server will try
768 to honor this value but actual latencies may be lower or higher.
770 ``-audiodev sdl,id=id[,prop[=value][,...]]``
771 Creates a backend using SDL. This backend is available on most
772 systems, but you should use your platform's native backend if
773 possible.
775 SDL specific options are:
777 ``in|out.buffer-count=count``
778 Sets the count of the buffers.
780 ``-audiodev spice,id=id[,prop[=value][,...]]``
781 Creates a backend that sends audio through SPICE. This backend
782 requires ``-spice`` and automatically selected in that case, so
783 usually you can ignore this option. This backend has no backend
784 specific properties.
786 ``-audiodev wav,id=id[,prop[=value][,...]]``
787 Creates a backend that writes audio to a WAV file.
789 Backend specific options are:
791 ``path=path``
792 Write recorded audio into the specified file. Default is
793 ``qemu.wav``.
794 ERST
796 DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
797 "-soundhw c1,... enable audio support\n"
798 " and only specified sound cards (comma separated list)\n"
799 " use '-soundhw help' to get the list of supported cards\n"
800 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
801 SRST
802 ``-soundhw card1[,card2,...] or -soundhw all``
803 Enable audio and selected sound hardware. Use 'help' to print all
804 available sound hardware. For example:
806 .. parsed-literal::
808 |qemu_system_x86| -soundhw sb16,adlib disk.img
809 |qemu_system_x86| -soundhw es1370 disk.img
810 |qemu_system_x86| -soundhw ac97 disk.img
811 |qemu_system_x86| -soundhw hda disk.img
812 |qemu_system_x86| -soundhw all disk.img
813 |qemu_system_x86| -soundhw help
815 Note that Linux's i810\_audio OSS kernel (for AC97) module might
816 require manually specifying clocking.
820 modprobe i810_audio clocking=48000
821 ERST
823 DEF("device", HAS_ARG, QEMU_OPTION_device,
824 "-device driver[,prop[=value][,...]]\n"
825 " add device (based on driver)\n"
826 " prop=value,... sets driver properties\n"
827 " use '-device help' to print all possible drivers\n"
828 " use '-device driver,help' to print all possible properties\n",
829 QEMU_ARCH_ALL)
830 SRST
831 ``-device driver[,prop[=value][,...]]``
832 Add device driver. prop=value sets driver properties. Valid
833 properties depend on the driver. To get help on possible drivers and
834 properties, use ``-device help`` and ``-device driver,help``.
836 Some drivers are:
838 ``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]``
839 Add an IPMI BMC. This is a simulation of a hardware management
840 interface processor that normally sits on a system. It provides a
841 watchdog and the ability to reset and power control the system. You
842 need to connect this to an IPMI interface to make it useful
844 The IPMI slave address to use for the BMC. The default is 0x20. This
845 address is the BMC's address on the I2C network of management
846 controllers. If you don't know what this means, it is safe to ignore
849 ``id=id``
850 The BMC id for interfaces to use this device.
852 ``slave_addr=val``
853 Define slave address to use for the BMC. The default is 0x20.
855 ``sdrfile=file``
856 file containing raw Sensor Data Records (SDR) data. The default
857 is none.
859 ``fruareasize=val``
860 size of a Field Replaceable Unit (FRU) area. The default is
861 1024.
863 ``frudatafile=file``
864 file containing raw Field Replaceable Unit (FRU) inventory data.
865 The default is none.
867 ``guid=uuid``
868 value for the GUID for the BMC, in standard UUID format. If this
869 is set, get "Get GUID" command to the BMC will return it.
870 Otherwise "Get GUID" will return an error.
872 ``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]``
873 Add a connection to an external IPMI BMC simulator. Instead of
874 locally emulating the BMC like the above item, instead connect to an
875 external entity that provides the IPMI services.
877 A connection is made to an external BMC simulator. If you do this,
878 it is strongly recommended that you use the "reconnect=" chardev
879 option to reconnect to the simulator if the connection is lost. Note
880 that if this is not used carefully, it can be a security issue, as
881 the interface has the ability to send resets, NMIs, and power off
882 the VM. It's best if QEMU makes a connection to an external
883 simulator running on a secure port on localhost, so neither the
884 simulator nor QEMU is exposed to any outside network.
886 See the "lanserv/README.vm" file in the OpenIPMI library for more
887 details on the external interface.
889 ``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]``
890 Add a KCS IPMI interafce on the ISA bus. This also adds a
891 corresponding ACPI and SMBIOS entries, if appropriate.
893 ``bmc=id``
894 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern
895 above.
897 ``ioport=val``
898 Define the I/O address of the interface. The default is 0xca0
899 for KCS.
901 ``irq=val``
902 Define the interrupt to use. The default is 5. To disable
903 interrupts, set this to 0.
905 ``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]``
906 Like the KCS interface, but defines a BT interface. The default port
907 is 0xe4 and the default interrupt is 5.
909 ``-device pci-ipmi-kcs,bmc=id``
910 Add a KCS IPMI interafce on the PCI bus.
912 ``bmc=id``
913 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
915 ``-device pci-ipmi-bt,bmc=id``
916 Like the KCS interface, but defines a BT interface on the PCI bus.
917 ERST
919 DEF("name", HAS_ARG, QEMU_OPTION_name,
920 "-name string1[,process=string2][,debug-threads=on|off]\n"
921 " set the name of the guest\n"
922 " string1 sets the window title and string2 the process name\n"
923 " When debug-threads is enabled, individual threads are given a separate name\n"
924 " NOTE: The thread names are for debugging and not a stable API.\n",
925 QEMU_ARCH_ALL)
926 SRST
927 ``-name name``
928 Sets the name of the guest. This name will be displayed in the SDL
929 window caption. The name will also be used for the VNC server. Also
930 optionally set the top visible process name in Linux. Naming of
931 individual threads can also be enabled on Linux to aid debugging.
932 ERST
934 DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
935 "-uuid %08x-%04x-%04x-%04x-%012x\n"
936 " specify machine UUID\n", QEMU_ARCH_ALL)
937 SRST
938 ``-uuid uuid``
939 Set system UUID.
940 ERST
942 DEFHEADING()
944 DEFHEADING(Block device options:)
946 DEF("fda", HAS_ARG, QEMU_OPTION_fda,
947 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
948 DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
949 SRST
950 ``-fda file``
952 ``-fdb file``
953 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in
954 the System Emulation Users Guide).
955 ERST
957 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
958 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
959 DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
960 DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
961 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
962 DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
963 SRST
964 ``-hda file``
966 ``-hdb file``
968 ``-hdc file``
970 ``-hdd file``
971 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images`
972 chapter in the System Emulation Users Guide).
973 ERST
975 DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
976 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
977 QEMU_ARCH_ALL)
978 SRST
979 ``-cdrom file``
980 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at
981 the same time). You can use the host CD-ROM by using ``/dev/cdrom``
982 as filename.
983 ERST
985 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
986 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
987 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
988 " [,read-only=on|off][,auto-read-only=on|off]\n"
989 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
990 " [,driver specific parameters...]\n"
991 " configure a block backend\n", QEMU_ARCH_ALL)
992 SRST
993 ``-blockdev option[,option[,option[,...]]]``
994 Define a new block driver node. Some of the options apply to all
995 block drivers, other options are only accepted for a specific block
996 driver. See below for a list of generic options and options for the
997 most common block drivers.
999 Options that expect a reference to another node (e.g. ``file``) can
1000 be given in two ways. Either you specify the node name of an already
1001 existing node (file=node-name), or you define a new node inline,
1002 adding options for the referenced node after a dot
1003 (file.filename=path,file.aio=native).
1005 A block driver node created with ``-blockdev`` can be used for a
1006 guest device by specifying its node name for the ``drive`` property
1007 in a ``-device`` argument that defines a block device.
1009 ``Valid options for any block driver node:``
1010 ``driver``
1011 Specifies the block driver to use for the given node.
1013 ``node-name``
1014 This defines the name of the block driver node by which it
1015 will be referenced later. The name must be unique, i.e. it
1016 must not match the name of a different block driver node, or
1017 (if you use ``-drive`` as well) the ID of a drive.
1019 If no node name is specified, it is automatically generated.
1020 The generated node name is not intended to be predictable
1021 and changes between QEMU invocations. For the top level, an
1022 explicit node name must be specified.
1024 ``read-only``
1025 Open the node read-only. Guest write attempts will fail.
1027 Note that some block drivers support only read-only access,
1028 either generally or in certain configurations. In this case,
1029 the default value ``read-only=off`` does not work and the
1030 option must be specified explicitly.
1032 ``auto-read-only``
1033 If ``auto-read-only=on`` is set, QEMU may fall back to
1034 read-only usage even when ``read-only=off`` is requested, or
1035 even switch between modes as needed, e.g. depending on
1036 whether the image file is writable or whether a writing user
1037 is attached to the node.
1039 ``force-share``
1040 Override the image locking system of QEMU by forcing the
1041 node to utilize weaker shared access for permissions where
1042 it would normally request exclusive access. When there is
1043 the potential for multiple instances to have the same file
1044 open (whether this invocation of QEMU is the first or the
1045 second instance), both instances must permit shared access
1046 for the second instance to succeed at opening the file.
1048 Enabling ``force-share=on`` requires ``read-only=on``.
1050 ``cache.direct``
1051 The host page cache can be avoided with ``cache.direct=on``.
1052 This will attempt to do disk IO directly to the guest's
1053 memory. QEMU may still perform an internal copy of the data.
1055 ``cache.no-flush``
1056 In case you don't care about data integrity over host
1057 failures, you can use ``cache.no-flush=on``. This option
1058 tells QEMU that it never needs to write any data to the disk
1059 but can instead keep things in cache. If anything goes
1060 wrong, like your host losing power, the disk storage getting
1061 disconnected accidentally, etc. your image will most
1062 probably be rendered unusable.
1064 ``discard=discard``
1065 discard is one of "ignore" (or "off") or "unmap" (or "on")
1066 and controls whether ``discard`` (also known as ``trim`` or
1067 ``unmap``) requests are ignored or passed to the filesystem.
1068 Some machine types may not support discard requests.
1070 ``detect-zeroes=detect-zeroes``
1071 detect-zeroes is "off", "on" or "unmap" and enables the
1072 automatic conversion of plain zero writes by the OS to
1073 driver specific optimized zero write commands. You may even
1074 choose "unmap" if discard is set to "unmap" to allow a zero
1075 write to be converted to an ``unmap`` operation.
1077 ``Driver-specific options for file``
1078 This is the protocol-level block driver for accessing regular
1079 files.
1081 ``filename``
1082 The path to the image file in the local filesystem
1084 ``aio``
1085 Specifies the AIO backend (threads/native/io_uring,
1086 default: threads)
1088 ``locking``
1089 Specifies whether the image file is protected with Linux OFD
1090 / POSIX locks. The default is to use the Linux Open File
1091 Descriptor API if available, otherwise no lock is applied.
1092 (auto/on/off, default: auto)
1094 Example:
1098 -blockdev driver=file,node-name=disk,filename=disk.img
1100 ``Driver-specific options for raw``
1101 This is the image format block driver for raw images. It is
1102 usually stacked on top of a protocol level block driver such as
1103 ``file``.
1105 ``file``
1106 Reference to or definition of the data source block driver
1107 node (e.g. a ``file`` driver node)
1109 Example 1:
1113 -blockdev driver=file,node-name=disk_file,filename=disk.img
1114 -blockdev driver=raw,node-name=disk,file=disk_file
1116 Example 2:
1120 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1122 ``Driver-specific options for qcow2``
1123 This is the image format block driver for qcow2 images. It is
1124 usually stacked on top of a protocol level block driver such as
1125 ``file``.
1127 ``file``
1128 Reference to or definition of the data source block driver
1129 node (e.g. a ``file`` driver node)
1131 ``backing``
1132 Reference to or definition of the backing file block device
1133 (default is taken from the image file). It is allowed to
1134 pass ``null`` here in order to disable the default backing
1135 file.
1137 ``lazy-refcounts``
1138 Whether to enable the lazy refcounts feature (on/off;
1139 default is taken from the image file)
1141 ``cache-size``
1142 The maximum total size of the L2 table and refcount block
1143 caches in bytes (default: the sum of l2-cache-size and
1144 refcount-cache-size)
1146 ``l2-cache-size``
1147 The maximum size of the L2 table cache in bytes (default: if
1148 cache-size is not specified - 32M on Linux platforms, and 8M
1149 on non-Linux platforms; otherwise, as large as possible
1150 within the cache-size, while permitting the requested or the
1151 minimal refcount cache size)
1153 ``refcount-cache-size``
1154 The maximum size of the refcount block cache in bytes
1155 (default: 4 times the cluster size; or if cache-size is
1156 specified, the part of it which is not used for the L2
1157 cache)
1159 ``cache-clean-interval``
1160 Clean unused entries in the L2 and refcount caches. The
1161 interval is in seconds. The default value is 600 on
1162 supporting platforms, and 0 on other platforms. Setting it
1163 to 0 disables this feature.
1165 ``pass-discard-request``
1166 Whether discard requests to the qcow2 device should be
1167 forwarded to the data source (on/off; default: on if
1168 discard=unmap is specified, off otherwise)
1170 ``pass-discard-snapshot``
1171 Whether discard requests for the data source should be
1172 issued when a snapshot operation (e.g. deleting a snapshot)
1173 frees clusters in the qcow2 file (on/off; default: on)
1175 ``pass-discard-other``
1176 Whether discard requests for the data source should be
1177 issued on other occasions where a cluster gets freed
1178 (on/off; default: off)
1180 ``overlap-check``
1181 Which overlap checks to perform for writes to the image
1182 (none/constant/cached/all; default: cached). For details or
1183 finer granularity control refer to the QAPI documentation of
1184 ``blockdev-add``.
1186 Example 1:
1190 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1191 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1193 Example 2:
1197 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1199 ``Driver-specific options for other drivers``
1200 Please refer to the QAPI documentation of the ``blockdev-add``
1201 QMP command.
1202 ERST
1204 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1205 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1206 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1207 " [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1208 " [,werror=ignore|stop|report|enospc][,id=name]\n"
1209 " [,aio=threads|native|io_uring]\n"
1210 " [,readonly=on|off][,copy-on-read=on|off]\n"
1211 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1212 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1213 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1214 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1215 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1216 " [[,iops_size=is]]\n"
1217 " [[,group=g]]\n"
1218 " use 'file' as a drive image\n", QEMU_ARCH_ALL)
1219 SRST
1220 ``-drive option[,option[,option[,...]]]``
1221 Define a new drive. This includes creating a block driver node (the
1222 backend) as well as a guest device, and is mostly a shortcut for
1223 defining the corresponding ``-blockdev`` and ``-device`` options.
1225 ``-drive`` accepts all options that are accepted by ``-blockdev``.
1226 In addition, it knows the following options:
1228 ``file=file``
1229 This option defines which disk image (see the :ref:`disk images`
1230 chapter in the System Emulation Users Guide) to use with this drive.
1231 If the filename contains comma, you must double it (for instance,
1232 "file=my,,file" to use file "my,file").
1234 Special files such as iSCSI devices can be specified using
1235 protocol specific URLs. See the section for "Device URL Syntax"
1236 for more information.
1238 ``if=interface``
1239 This option defines on which type on interface the drive is
1240 connected. Available types are: ide, scsi, sd, mtd, floppy,
1241 pflash, virtio, none.
1243 ``bus=bus,unit=unit``
1244 These options define where is connected the drive by defining
1245 the bus number and the unit id.
1247 ``index=index``
1248 This option defines where is connected the drive by using an
1249 index in the list of available connectors of a given interface
1250 type.
1252 ``media=media``
1253 This option defines the type of the media: disk or cdrom.
1255 ``snapshot=snapshot``
1256 snapshot is "on" or "off" and controls snapshot mode for the
1257 given drive (see ``-snapshot``).
1259 ``cache=cache``
1260 cache is "none", "writeback", "unsafe", "directsync" or
1261 "writethrough" and controls how the host cache is used to access
1262 block data. This is a shortcut that sets the ``cache.direct``
1263 and ``cache.no-flush`` options (as in ``-blockdev``), and
1264 additionally ``cache.writeback``, which provides a default for
1265 the ``write-cache`` option of block guest devices (as in
1266 ``-device``). The modes correspond to the following settings:
1268 ============= =============== ============ ==============
1269 \ cache.writeback cache.direct cache.no-flush
1270 ============= =============== ============ ==============
1271 writeback on off off
1272 none on on off
1273 writethrough off off off
1274 directsync off on off
1275 unsafe on off on
1276 ============= =============== ============ ==============
1278 The default mode is ``cache=writeback``.
1280 ``aio=aio``
1281 aio is "threads", "native", or "io_uring" and selects between pthread
1282 based disk I/O, native Linux AIO, or Linux io_uring API.
1284 ``format=format``
1285 Specify which disk format will be used rather than detecting the
1286 format. Can be used to specify format=raw to avoid interpreting
1287 an untrusted format header.
1289 ``werror=action,rerror=action``
1290 Specify which action to take on write and read errors. Valid
1291 actions are: "ignore" (ignore the error and try to continue),
1292 "stop" (pause QEMU), "report" (report the error to the guest),
1293 "enospc" (pause QEMU only if the host disk is full; report the
1294 error to the guest otherwise). The default setting is
1295 ``werror=enospc`` and ``rerror=report``.
1297 ``copy-on-read=copy-on-read``
1298 copy-on-read is "on" or "off" and enables whether to copy read
1299 backing file sectors into the image file.
1301 ``bps=b,bps_rd=r,bps_wr=w``
1302 Specify bandwidth throttling limits in bytes per second, either
1303 for all request types or for reads or writes only. Small values
1304 can lead to timeouts or hangs inside the guest. A safe minimum
1305 for disks is 2 MB/s.
1307 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm``
1308 Specify bursts in bytes per second, either for all request types
1309 or for reads or writes only. Bursts allow the guest I/O to spike
1310 above the limit temporarily.
1312 ``iops=i,iops_rd=r,iops_wr=w``
1313 Specify request rate limits in requests per second, either for
1314 all request types or for reads or writes only.
1316 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm``
1317 Specify bursts in requests per second, either for all request
1318 types or for reads or writes only. Bursts allow the guest I/O to
1319 spike above the limit temporarily.
1321 ``iops_size=is``
1322 Let every is bytes of a request count as a new request for iops
1323 throttling purposes. Use this option to prevent guests from
1324 circumventing iops limits by sending fewer but larger requests.
1326 ``group=g``
1327 Join a throttling quota group with given name g. All drives that
1328 are members of the same group are accounted for together. Use
1329 this option to prevent guests from circumventing throttling
1330 limits by using many small disks instead of a single larger
1331 disk.
1333 By default, the ``cache.writeback=on`` mode is used. It will report
1334 data writes as completed as soon as the data is present in the host
1335 page cache. This is safe as long as your guest OS makes sure to
1336 correctly flush disk caches where needed. If your guest OS does not
1337 handle volatile disk write caches correctly and your host crashes or
1338 loses power, then the guest may experience data corruption.
1340 For such guests, you should consider using ``cache.writeback=off``.
1341 This means that the host page cache will be used to read and write
1342 data, but write notification will be sent to the guest only after
1343 QEMU has made sure to flush each write to the disk. Be aware that
1344 this has a major impact on performance.
1346 When using the ``-snapshot`` option, unsafe caching is always used.
1348 Copy-on-read avoids accessing the same backing file sectors
1349 repeatedly and is useful when the backing file is over a slow
1350 network. By default copy-on-read is off.
1352 Instead of ``-cdrom`` you can use:
1354 .. parsed-literal::
1356 |qemu_system| -drive file=file,index=2,media=cdrom
1358 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use:
1360 .. parsed-literal::
1362 |qemu_system| -drive file=file,index=0,media=disk
1363 |qemu_system| -drive file=file,index=1,media=disk
1364 |qemu_system| -drive file=file,index=2,media=disk
1365 |qemu_system| -drive file=file,index=3,media=disk
1367 You can open an image using pre-opened file descriptors from an fd
1368 set:
1370 .. parsed-literal::
1372 |qemu_system| \\
1373 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
1374 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
1375 -drive file=/dev/fdset/2,index=0,media=disk
1377 You can connect a CDROM to the slave of ide0:
1379 .. parsed-literal::
1381 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom
1383 If you don't specify the "file=" argument, you define an empty
1384 drive:
1386 .. parsed-literal::
1388 |qemu_system_x86| -drive if=ide,index=1,media=cdrom
1390 Instead of ``-fda``, ``-fdb``, you can use:
1392 .. parsed-literal::
1394 |qemu_system_x86| -drive file=file,index=0,if=floppy
1395 |qemu_system_x86| -drive file=file,index=1,if=floppy
1397 By default, interface is "ide" and index is automatically
1398 incremented:
1400 .. parsed-literal::
1402 |qemu_system_x86| -drive file=a -drive file=b"
1404 is interpreted like:
1406 .. parsed-literal::
1408 |qemu_system_x86| -hda a -hdb b
1409 ERST
1411 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1412 "-mtdblock file use 'file' as on-board Flash memory image\n",
1413 QEMU_ARCH_ALL)
1414 SRST
1415 ``-mtdblock file``
1416 Use file as on-board Flash memory image.
1417 ERST
1419 DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1420 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1421 SRST
1422 ``-sd file``
1423 Use file as SecureDigital card image.
1424 ERST
1426 DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
1427 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
1428 SRST
1429 ``-pflash file``
1430 Use file as a parallel flash image.
1431 ERST
1433 DEF("snapshot", 0, QEMU_OPTION_snapshot,
1434 "-snapshot write to temporary files instead of disk image files\n",
1435 QEMU_ARCH_ALL)
1436 SRST
1437 ``-snapshot``
1438 Write to temporary files instead of disk image files. In this case,
1439 the raw disk image you use is not written back. You can however
1440 force the write back by pressing C-a s (see the :ref:`disk images`
1441 chapter in the System Emulation Users Guide).
1442 ERST
1444 DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1445 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1446 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n"
1447 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1448 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1449 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1450 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1451 " [[,throttling.iops-size=is]]\n"
1452 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n"
1453 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n"
1454 "-fsdev synth,id=id\n",
1455 QEMU_ARCH_ALL)
1457 SRST
1458 ``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]``
1460 ``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]``
1462 ``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]``
1464 ``-fsdev synth,id=id[,readonly=on]``
1465 Define a new file system device. Valid options are:
1467 ``local``
1468 Accesses to the filesystem are done by QEMU.
1470 ``proxy``
1471 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1473 ``synth``
1474 Synthetic filesystem, only used by QTests.
1476 ``id=id``
1477 Specifies identifier for this device.
1479 ``path=path``
1480 Specifies the export path for the file system device. Files
1481 under this path will be available to the 9p client on the guest.
1483 ``security_model=security_model``
1484 Specifies the security model to be used for this export path.
1485 Supported security models are "passthrough", "mapped-xattr",
1486 "mapped-file" and "none". In "passthrough" security model, files
1487 are stored using the same credentials as they are created on the
1488 guest. This requires QEMU to run as root. In "mapped-xattr"
1489 security model, some of the file attributes like uid, gid, mode
1490 bits and link target are stored as file attributes. For
1491 "mapped-file" these attributes are stored in the hidden
1492 .virtfs\_metadata directory. Directories exported by this
1493 security model cannot interact with other unix tools. "none"
1494 security model is same as passthrough except the sever won't
1495 report failures if it fails to set file attributes like
1496 ownership. Security model is mandatory only for local fsdriver.
1497 Other fsdrivers (like proxy) don't take security model as a
1498 parameter.
1500 ``writeout=writeout``
1501 This is an optional argument. The only supported value is
1502 "immediate". This means that host page cache will be used to
1503 read and write data but write notification will be sent to the
1504 guest only when the data has been reported as written by the
1505 storage subsystem.
1507 ``readonly=on``
1508 Enables exporting 9p share as a readonly mount for guests. By
1509 default read-write access is given.
1511 ``socket=socket``
1512 Enables proxy filesystem driver to use passed socket file for
1513 communicating with virtfs-proxy-helper(1).
1515 ``sock_fd=sock_fd``
1516 Enables proxy filesystem driver to use passed socket descriptor
1517 for communicating with virtfs-proxy-helper(1). Usually a helper
1518 like libvirt will create socketpair and pass one of the fds as
1519 sock\_fd.
1521 ``fmode=fmode``
1522 Specifies the default mode for newly created files on the host.
1523 Works only with security models "mapped-xattr" and
1524 "mapped-file".
1526 ``dmode=dmode``
1527 Specifies the default mode for newly created directories on the
1528 host. Works only with security models "mapped-xattr" and
1529 "mapped-file".
1531 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w``
1532 Specify bandwidth throttling limits in bytes per second, either
1533 for all request types or for reads or writes only.
1535 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm``
1536 Specify bursts in bytes per second, either for all request types
1537 or for reads or writes only. Bursts allow the guest I/O to spike
1538 above the limit temporarily.
1540 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w``
1541 Specify request rate limits in requests per second, either for
1542 all request types or for reads or writes only.
1544 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm``
1545 Specify bursts in requests per second, either for all request
1546 types or for reads or writes only. Bursts allow the guest I/O to
1547 spike above the limit temporarily.
1549 ``throttling.iops-size=is``
1550 Let every is bytes of a request count as a new request for iops
1551 throttling purposes.
1553 -fsdev option is used along with -device driver "virtio-9p-...".
1555 ``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag``
1556 Options for virtio-9p-... driver are:
1558 ``type``
1559 Specifies the variant to be used. Supported values are "pci",
1560 "ccw" or "device", depending on the machine type.
1562 ``fsdev=id``
1563 Specifies the id value specified along with -fsdev option.
1565 ``mount_tag=mount_tag``
1566 Specifies the tag name to be used by the guest to mount this
1567 export point.
1568 ERST
1570 DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1571 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1572 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n"
1573 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n"
1574 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n"
1575 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n",
1576 QEMU_ARCH_ALL)
1578 SRST
1579 ``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]``
1581 ``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1583 ``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1585 ``-virtfs synth,mount_tag=mount_tag``
1586 Define a new virtual filesystem device and expose it to the guest using
1587 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain
1588 directory on host is made directly accessible by guest as a pass-through
1589 file system by using the 9P network protocol for communication between
1590 host and guests, if desired even accessible, shared by several guests
1591 simultaniously.
1593 Note that ``-virtfs`` is actually just a convenience shortcut for its
1594 generalized form ``-fsdev -device virtio-9p-pci``.
1596 The general form of pass-through file system options are:
1598 ``local``
1599 Accesses to the filesystem are done by QEMU.
1601 ``proxy``
1602 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1604 ``synth``
1605 Synthetic filesystem, only used by QTests.
1607 ``id=id``
1608 Specifies identifier for the filesystem device
1610 ``path=path``
1611 Specifies the export path for the file system device. Files
1612 under this path will be available to the 9p client on the guest.
1614 ``security_model=security_model``
1615 Specifies the security model to be used for this export path.
1616 Supported security models are "passthrough", "mapped-xattr",
1617 "mapped-file" and "none". In "passthrough" security model, files
1618 are stored using the same credentials as they are created on the
1619 guest. This requires QEMU to run as root. In "mapped-xattr"
1620 security model, some of the file attributes like uid, gid, mode
1621 bits and link target are stored as file attributes. For
1622 "mapped-file" these attributes are stored in the hidden
1623 .virtfs\_metadata directory. Directories exported by this
1624 security model cannot interact with other unix tools. "none"
1625 security model is same as passthrough except the sever won't
1626 report failures if it fails to set file attributes like
1627 ownership. Security model is mandatory only for local fsdriver.
1628 Other fsdrivers (like proxy) don't take security model as a
1629 parameter.
1631 ``writeout=writeout``
1632 This is an optional argument. The only supported value is
1633 "immediate". This means that host page cache will be used to
1634 read and write data but write notification will be sent to the
1635 guest only when the data has been reported as written by the
1636 storage subsystem.
1638 ``readonly=on``
1639 Enables exporting 9p share as a readonly mount for guests. By
1640 default read-write access is given.
1642 ``socket=socket``
1643 Enables proxy filesystem driver to use passed socket file for
1644 communicating with virtfs-proxy-helper(1). Usually a helper like
1645 libvirt will create socketpair and pass one of the fds as
1646 sock\_fd.
1648 ``sock_fd``
1649 Enables proxy filesystem driver to use passed 'sock\_fd' as the
1650 socket descriptor for interfacing with virtfs-proxy-helper(1).
1652 ``fmode=fmode``
1653 Specifies the default mode for newly created files on the host.
1654 Works only with security models "mapped-xattr" and
1655 "mapped-file".
1657 ``dmode=dmode``
1658 Specifies the default mode for newly created directories on the
1659 host. Works only with security models "mapped-xattr" and
1660 "mapped-file".
1662 ``mount_tag=mount_tag``
1663 Specifies the tag name to be used by the guest to mount this
1664 export point.
1666 ``multidevs=multidevs``
1667 Specifies how to deal with multiple devices being shared with a
1668 9p export. Supported behaviours are either "remap", "forbid" or
1669 "warn". The latter is the default behaviour on which virtfs 9p
1670 expects only one device to be shared with the same export, and
1671 if more than one device is shared and accessed via the same 9p
1672 export then only a warning message is logged (once) by qemu on
1673 host side. In order to avoid file ID collisions on guest you
1674 should either create a separate virtfs export for each device to
1675 be shared with guests (recommended way) or you might use "remap"
1676 instead which allows you to share multiple devices with only one
1677 export instead, which is achieved by remapping the original
1678 inode numbers from host to guest in a way that would prevent
1679 such collisions. Remapping inodes in such use cases is required
1680 because the original device IDs from host are never passed and
1681 exposed on guest. Instead all files of an export shared with
1682 virtfs always share the same device id on guest. So two files
1683 with identical inode numbers but from actually different devices
1684 on host would otherwise cause a file ID collision and hence
1685 potential misbehaviours on guest. "forbid" on the other hand
1686 assumes like "warn" that only one device is shared by the same
1687 export, however it will not only log a warning message but also
1688 deny access to additional devices on guest. Note though that
1689 "forbid" does currently not block all possible file access
1690 operations (e.g. readdir() would still return entries from other
1691 devices).
1692 ERST
1694 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1695 "-iscsi [user=user][,password=password]\n"
1696 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1697 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1698 " [,timeout=timeout]\n"
1699 " iSCSI session parameters\n", QEMU_ARCH_ALL)
1701 SRST
1702 ``-iscsi``
1703 Configure iSCSI session parameters.
1704 ERST
1706 DEFHEADING()
1708 DEFHEADING(USB convenience options:)
1710 DEF("usb", 0, QEMU_OPTION_usb,
1711 "-usb enable on-board USB host controller (if not enabled by default)\n",
1712 QEMU_ARCH_ALL)
1713 SRST
1714 ``-usb``
1715 Enable USB emulation on machine types with an on-board USB host
1716 controller (if not enabled by default). Note that on-board USB host
1717 controllers may not support USB 3.0. In this case
1718 ``-device qemu-xhci`` can be used instead on machines with PCI.
1719 ERST
1721 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1722 "-usbdevice name add the host or guest USB device 'name'\n",
1723 QEMU_ARCH_ALL)
1724 SRST
1725 ``-usbdevice devname``
1726 Add the USB device devname, and enable an on-board USB controller
1727 if possible and necessary (just like it can be done via
1728 ``-machine usb=on``). Note that this option is mainly intended for
1729 the user's convenience only. More fine-grained control can be
1730 achieved by selecting a USB host controller (if necessary) and the
1731 desired USB device via the ``-device`` option instead. For example,
1732 instead of using ``-usbdevice mouse`` it is possible to use
1733 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse
1734 to a USB 3.0 controller instead (at least on machines that support
1735 PCI and do not have an USB controller enabled by default yet).
1736 For more details, see the chapter about
1737 :ref:`Connecting USB devices` in the System Emulation Users Guide.
1738 Possible devices for devname are:
1740 ``braille``
1741 Braille device. This will use BrlAPI to display the braille
1742 output on a real or fake device (i.e. it also creates a
1743 corresponding ``braille`` chardev automatically beside the
1744 ``usb-braille`` USB device).
1746 ``keyboard``
1747 Standard USB keyboard. Will override the PS/2 keyboard (if present).
1749 ``mouse``
1750 Virtual Mouse. This will override the PS/2 mouse emulation when
1751 activated.
1753 ``tablet``
1754 Pointer device that uses absolute coordinates (like a
1755 touchscreen). This means QEMU is able to report the mouse
1756 position without having to grab the mouse. Also overrides the
1757 PS/2 mouse emulation when activated.
1759 ``wacom-tablet``
1760 Wacom PenPartner USB tablet.
1763 ERST
1765 DEFHEADING()
1767 DEFHEADING(Display options:)
1769 DEF("display", HAS_ARG, QEMU_OPTION_display,
1770 #if defined(CONFIG_SPICE)
1771 "-display spice-app[,gl=on|off]\n"
1772 #endif
1773 #if defined(CONFIG_SDL)
1774 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n"
1775 " [,window_close=on|off][,gl=on|core|es|off]\n"
1776 #endif
1777 #if defined(CONFIG_GTK)
1778 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1779 #endif
1780 #if defined(CONFIG_VNC)
1781 "-display vnc=<display>[,<optargs>]\n"
1782 #endif
1783 #if defined(CONFIG_CURSES)
1784 "-display curses[,charset=<encoding>]\n"
1785 #endif
1786 #if defined(CONFIG_OPENGL)
1787 "-display egl-headless[,rendernode=<file>]\n"
1788 #endif
1789 "-display none\n"
1790 " select display backend type\n"
1791 " The default display is equivalent to\n "
1792 #if defined(CONFIG_GTK)
1793 "\"-display gtk\"\n"
1794 #elif defined(CONFIG_SDL)
1795 "\"-display sdl\"\n"
1796 #elif defined(CONFIG_COCOA)
1797 "\"-display cocoa\"\n"
1798 #elif defined(CONFIG_VNC)
1799 "\"-vnc localhost:0,to=99,id=default\"\n"
1800 #else
1801 "\"-display none\"\n"
1802 #endif
1803 , QEMU_ARCH_ALL)
1804 SRST
1805 ``-display type``
1806 Select type of display to use. This option is a replacement for the
1807 old style -sdl/-curses/... options. Use ``-display help`` to list
1808 the available display types. Valid values for type are
1810 ``sdl``
1811 Display video output via SDL (usually in a separate graphics
1812 window; see the SDL documentation for other possibilities).
1814 ``curses``
1815 Display video output via curses. For graphics device models
1816 which support a text mode, QEMU can display this output using a
1817 curses/ncurses interface. Nothing is displayed when the graphics
1818 device is in graphical mode or if the graphics device does not
1819 support a text mode. Generally only the VGA device models
1820 support text mode. The font charset used by the guest can be
1821 specified with the ``charset`` option, for example
1822 ``charset=CP850`` for IBM CP850 encoding. The default is
1823 ``CP437``.
1825 ``none``
1826 Do not display video output. The guest will still see an
1827 emulated graphics card, but its output will not be displayed to
1828 the QEMU user. This option differs from the -nographic option in
1829 that it only affects what is done with video output; -nographic
1830 also changes the destination of the serial and parallel port
1831 data.
1833 ``gtk``
1834 Display video output in a GTK window. This interface provides
1835 drop-down menus and other UI elements to configure and control
1836 the VM during runtime.
1838 ``vnc``
1839 Start a VNC server on display <arg>
1841 ``egl-headless``
1842 Offload all OpenGL operations to a local DRI device. For any
1843 graphical display, this display needs to be paired with either
1844 VNC or SPICE displays.
1846 ``spice-app``
1847 Start QEMU as a Spice server and launch the default Spice client
1848 application. The Spice server will redirect the serial consoles
1849 and QEMU monitors. (Since 4.0)
1850 ERST
1852 DEF("nographic", 0, QEMU_OPTION_nographic,
1853 "-nographic disable graphical output and redirect serial I/Os to console\n",
1854 QEMU_ARCH_ALL)
1855 SRST
1856 ``-nographic``
1857 Normally, if QEMU is compiled with graphical window support, it
1858 displays output such as guest graphics, guest console, and the QEMU
1859 monitor in a window. With this option, you can totally disable
1860 graphical output so that QEMU is a simple command line application.
1861 The emulated serial port is redirected on the console and muxed with
1862 the monitor (unless redirected elsewhere explicitly). Therefore, you
1863 can still use QEMU to debug a Linux kernel with a serial console.
1864 Use C-a h for help on switching between the console and monitor.
1865 ERST
1867 DEF("curses", 0, QEMU_OPTION_curses,
1868 "-curses shorthand for -display curses\n",
1869 QEMU_ARCH_ALL)
1870 SRST
1871 ``-curses``
1872 Normally, if QEMU is compiled with graphical window support, it
1873 displays output such as guest graphics, guest console, and the QEMU
1874 monitor in a window. With this option, QEMU can display the VGA
1875 output when in text mode using a curses/ncurses interface. Nothing
1876 is displayed in graphical mode.
1877 ERST
1879 DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1880 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1881 QEMU_ARCH_ALL)
1882 SRST
1883 ``-alt-grab``
1884 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that
1885 this also affects the special keys (for fullscreen, monitor-mode
1886 switching, etc).
1887 ERST
1889 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1890 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1891 QEMU_ARCH_ALL)
1892 SRST
1893 ``-ctrl-grab``
1894 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this
1895 also affects the special keys (for fullscreen, monitor-mode
1896 switching, etc).
1897 ERST
1899 DEF("no-quit", 0, QEMU_OPTION_no_quit,
1900 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL)
1901 SRST
1902 ``-no-quit``
1903 Disable SDL window close capability.
1904 ERST
1906 DEF("sdl", 0, QEMU_OPTION_sdl,
1907 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL)
1908 SRST
1909 ``-sdl``
1910 Enable SDL.
1911 ERST
1913 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1914 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1915 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1916 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1917 " [,x509-dh-key-file=<file>][,addr=addr]\n"
1918 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n"
1919 " [,tls-ciphers=<list>]\n"
1920 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1921 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1922 " [,sasl=on|off][,disable-ticketing=on|off]\n"
1923 " [,password=<string>][,password-secret=<secret-id>]\n"
1924 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1925 " [,jpeg-wan-compression=[auto|never|always]]\n"
1926 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
1927 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
1928 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
1929 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1930 " [,gl=[on|off]][,rendernode=<file>]\n"
1931 " enable spice\n"
1932 " at least one of {port, tls-port} is mandatory\n",
1933 QEMU_ARCH_ALL)
1934 SRST
1935 ``-spice option[,option[,...]]``
1936 Enable the spice remote desktop protocol. Valid options are
1938 ``port=<nr>``
1939 Set the TCP port spice is listening on for plaintext channels.
1941 ``addr=<addr>``
1942 Set the IP address spice is listening on. Default is any
1943 address.
1945 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off``
1946 Force using the specified IP version.
1948 ``password=<string>``
1949 Set the password you need to authenticate.
1951 This option is deprecated and insecure because it leaves the
1952 password visible in the process listing. Use ``password-secret``
1953 instead.
1955 ``password-secret=<secret-id>``
1956 Set the ID of the ``secret`` object containing the password
1957 you need to authenticate.
1959 ``sasl=on|off``
1960 Require that the client use SASL to authenticate with the spice.
1961 The exact choice of authentication method used is controlled
1962 from the system / user's SASL configuration file for the 'qemu'
1963 service. This is typically found in /etc/sasl2/qemu.conf. If
1964 running QEMU as an unprivileged user, an environment variable
1965 SASL\_CONF\_PATH can be used to make it search alternate
1966 locations for the service config. While some SASL auth methods
1967 can also provide data encryption (eg GSSAPI), it is recommended
1968 that SASL always be combined with the 'tls' and 'x509' settings
1969 to enable use of SSL and server certificates. This ensures a
1970 data encryption preventing compromise of authentication
1971 credentials.
1973 ``disable-ticketing=on|off``
1974 Allow client connects without authentication.
1976 ``disable-copy-paste=on|off``
1977 Disable copy paste between the client and the guest.
1979 ``disable-agent-file-xfer=on|off``
1980 Disable spice-vdagent based file-xfer between the client and the
1981 guest.
1983 ``tls-port=<nr>``
1984 Set the TCP port spice is listening on for encrypted channels.
1986 ``x509-dir=<dir>``
1987 Set the x509 file directory. Expects same filenames as -vnc
1988 $display,x509=$dir
1990 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>``
1991 The x509 file names can also be configured individually.
1993 ``tls-ciphers=<list>``
1994 Specify which ciphers to use.
1996 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]``
1997 Force specific channel to be used with or without TLS
1998 encryption. The options can be specified multiple times to
1999 configure multiple channels. The special name "default" can be
2000 used to set the default mode. For channels which are not
2001 explicitly forced into one mode the spice client is allowed to
2002 pick tls/plaintext as he pleases.
2004 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]``
2005 Configure image compression (lossless). Default is auto\_glz.
2007 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]``
2008 Configure wan image compression (lossy for slow links). Default
2009 is auto.
2011 ``streaming-video=[off|all|filter]``
2012 Configure video stream detection. Default is off.
2014 ``agent-mouse=[on|off]``
2015 Enable/disable passing mouse events via vdagent. Default is on.
2017 ``playback-compression=[on|off]``
2018 Enable/disable audio stream compression (using celt 0.5.1).
2019 Default is on.
2021 ``seamless-migration=[on|off]``
2022 Enable/disable spice seamless migration. Default is off.
2024 ``gl=[on|off]``
2025 Enable/disable OpenGL context. Default is off.
2027 ``rendernode=<file>``
2028 DRM render node for OpenGL rendering. If not specified, it will
2029 pick the first available. (Since 2.9)
2030 ERST
2032 DEF("portrait", 0, QEMU_OPTION_portrait,
2033 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
2034 QEMU_ARCH_ALL)
2035 SRST
2036 ``-portrait``
2037 Rotate graphical output 90 deg left (only PXA LCD).
2038 ERST
2040 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
2041 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
2042 QEMU_ARCH_ALL)
2043 SRST
2044 ``-rotate deg``
2045 Rotate graphical output some deg left (only PXA LCD).
2046 ERST
2048 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
2049 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
2050 " select video card type\n", QEMU_ARCH_ALL)
2051 SRST
2052 ``-vga type``
2053 Select type of VGA card to emulate. Valid values for type are
2055 ``cirrus``
2056 Cirrus Logic GD5446 Video card. All Windows versions starting
2057 from Windows 95 should recognize and use this graphic card. For
2058 optimal performances, use 16 bit color depth in the guest and
2059 the host OS. (This card was the default before QEMU 2.2)
2061 ``std``
2062 Standard VGA card with Bochs VBE extensions. If your guest OS
2063 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if
2064 you want to use high resolution modes (>= 1280x1024x16) then you
2065 should use this option. (This card is the default since QEMU
2066 2.2)
2068 ``vmware``
2069 VMWare SVGA-II compatible adapter. Use it if you have
2070 sufficiently recent XFree86/XOrg server or Windows guest with a
2071 driver for this card.
2073 ``qxl``
2074 QXL paravirtual graphic card. It is VGA compatible (including
2075 VESA 2.0 VBE support). Works best with qxl guest drivers
2076 installed though. Recommended choice when using the spice
2077 protocol.
2079 ``tcx``
2080 (sun4m only) Sun TCX framebuffer. This is the default
2081 framebuffer for sun4m machines and offers both 8-bit and 24-bit
2082 colour depths at a fixed resolution of 1024x768.
2084 ``cg3``
2085 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit
2086 framebuffer for sun4m machines available in both 1024x768
2087 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people
2088 wishing to run older Solaris versions.
2090 ``virtio``
2091 Virtio VGA card.
2093 ``none``
2094 Disable VGA card.
2095 ERST
2097 DEF("full-screen", 0, QEMU_OPTION_full_screen,
2098 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
2099 SRST
2100 ``-full-screen``
2101 Start in full screen.
2102 ERST
2104 DEF("g", HAS_ARG, QEMU_OPTION_g ,
2105 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
2106 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
2107 SRST
2108 ``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]``
2109 Set the initial graphical resolution and depth (PPC, SPARC only).
2111 For PPC the default is 800x600x32.
2113 For SPARC with the TCX graphics device, the default is 1024x768x8
2114 with the option of 1024x768x24. For cgthree, the default is
2115 1024x768x8 with the option of 1152x900x8 for people who wish to use
2116 OBP.
2117 ERST
2119 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
2120 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
2121 SRST
2122 ``-vnc display[,option[,option[,...]]]``
2123 Normally, if QEMU is compiled with graphical window support, it
2124 displays output such as guest graphics, guest console, and the QEMU
2125 monitor in a window. With this option, you can have QEMU listen on
2126 VNC display display and redirect the VGA display over the VNC
2127 session. It is very useful to enable the usb tablet device when
2128 using this option (option ``-device usb-tablet``). When using the
2129 VNC display, you must use the ``-k`` parameter to set the keyboard
2130 layout if you are not using en-us. Valid syntax for the display is
2132 ``to=L``
2133 With this option, QEMU will try next available VNC displays,
2134 until the number L, if the origianlly defined "-vnc display" is
2135 not available, e.g. port 5900+display is already used by another
2136 application. By default, to=0.
2138 ``host:d``
2139 TCP connections will only be allowed from host on display d. By
2140 convention the TCP port is 5900+d. Optionally, host can be
2141 omitted in which case the server will accept connections from
2142 any host.
2144 ``unix:path``
2145 Connections will be allowed over UNIX domain sockets where path
2146 is the location of a unix socket to listen for connections on.
2148 ``none``
2149 VNC is initialized but not started. The monitor ``change``
2150 command can be used to later start the VNC server.
2152 Following the display value there may be one or more option flags
2153 separated by commas. Valid options are
2155 ``reverse=on|off``
2156 Connect to a listening VNC client via a "reverse" connection.
2157 The client is specified by the display. For reverse network
2158 connections (host:d,``reverse``), the d argument is a TCP port
2159 number, not a display number.
2161 ``websocket=on|off``
2162 Opens an additional TCP listening port dedicated to VNC
2163 Websocket connections. If a bare websocket option is given, the
2164 Websocket port is 5700+display. An alternative port can be
2165 specified with the syntax ``websocket``\ =port.
2167 If host is specified connections will only be allowed from this
2168 host. It is possible to control the websocket listen address
2169 independently, using the syntax ``websocket``\ =host:port.
2171 If no TLS credentials are provided, the websocket connection
2172 runs in unencrypted mode. If TLS credentials are provided, the
2173 websocket connection requires encrypted client connections.
2175 ``password=on|off``
2176 Require that password based authentication is used for client
2177 connections.
2179 The password must be set separately using the ``set_password``
2180 command in the :ref:`QEMU monitor`. The
2181 syntax to change your password is:
2182 ``set_password <protocol> <password>`` where <protocol> could be
2183 either "vnc" or "spice".
2185 If you would like to change <protocol> password expiration, you
2186 should use ``expire_password <protocol> <expiration-time>``
2187 where expiration time could be one of the following options:
2188 now, never, +seconds or UNIX time of expiration, e.g. +60 to
2189 make password expire in 60 seconds, or 1335196800 to make
2190 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for
2191 this date and time).
2193 You can also use keywords "now" or "never" for the expiration
2194 time to allow <protocol> password to expire immediately or never
2195 expire.
2197 ``password-secret=<secret-id>``
2198 Require that password based authentication is used for client
2199 connections, using the password provided by the ``secret``
2200 object identified by ``secret-id``.
2202 ``tls-creds=ID``
2203 Provides the ID of a set of TLS credentials to use to secure the
2204 VNC server. They will apply to both the normal VNC server socket
2205 and the websocket socket (if enabled). Setting TLS credentials
2206 will cause the VNC server socket to enable the VeNCrypt auth
2207 mechanism. The credentials should have been previously created
2208 using the ``-object tls-creds`` argument.
2210 ``tls-authz=ID``
2211 Provides the ID of the QAuthZ authorization object against which
2212 the client's x509 distinguished name will validated. This object
2213 is only resolved at time of use, so can be deleted and recreated
2214 on the fly while the VNC server is active. If missing, it will
2215 default to denying access.
2217 ``sasl=on|off``
2218 Require that the client use SASL to authenticate with the VNC
2219 server. The exact choice of authentication method used is
2220 controlled from the system / user's SASL configuration file for
2221 the 'qemu' service. This is typically found in
2222 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user,
2223 an environment variable SASL\_CONF\_PATH can be used to make it
2224 search alternate locations for the service config. While some
2225 SASL auth methods can also provide data encryption (eg GSSAPI),
2226 it is recommended that SASL always be combined with the 'tls'
2227 and 'x509' settings to enable use of SSL and server
2228 certificates. This ensures a data encryption preventing
2229 compromise of authentication credentials. See the
2230 :ref:`VNC security` section in the System Emulation Users Guide
2231 for details on using SASL authentication.
2233 ``sasl-authz=ID``
2234 Provides the ID of the QAuthZ authorization object against which
2235 the client's SASL username will validated. This object is only
2236 resolved at time of use, so can be deleted and recreated on the
2237 fly while the VNC server is active. If missing, it will default
2238 to denying access.
2240 ``acl=on|off``
2241 Legacy method for enabling authorization of clients against the
2242 x509 distinguished name and SASL username. It results in the
2243 creation of two ``authz-list`` objects with IDs of
2244 ``vnc.username`` and ``vnc.x509dname``. The rules for these
2245 objects must be configured with the HMP ACL commands.
2247 This option is deprecated and should no longer be used. The new
2248 ``sasl-authz`` and ``tls-authz`` options are a replacement.
2250 ``lossy=on|off``
2251 Enable lossy compression methods (gradient, JPEG, ...). If this
2252 option is set, VNC client may receive lossy framebuffer updates
2253 depending on its encoding settings. Enabling this option can
2254 save a lot of bandwidth at the expense of quality.
2256 ``non-adaptive=on|off``
2257 Disable adaptive encodings. Adaptive encodings are enabled by
2258 default. An adaptive encoding will try to detect frequently
2259 updated screen regions, and send updates in these regions using
2260 a lossy encoding (like JPEG). This can be really helpful to save
2261 bandwidth when playing videos. Disabling adaptive encodings
2262 restores the original static behavior of encodings like Tight.
2264 ``share=[allow-exclusive|force-shared|ignore]``
2265 Set display sharing policy. 'allow-exclusive' allows clients to
2266 ask for exclusive access. As suggested by the rfb spec this is
2267 implemented by dropping other connections. Connecting multiple
2268 clients in parallel requires all clients asking for a shared
2269 session (vncviewer: -shared switch). This is the default.
2270 'force-shared' disables exclusive client access. Useful for
2271 shared desktop sessions, where you don't want someone forgetting
2272 specify -shared disconnect everybody else. 'ignore' completely
2273 ignores the shared flag and allows everybody connect
2274 unconditionally. Doesn't conform to the rfb spec but is
2275 traditional QEMU behavior.
2277 ``key-delay-ms``
2278 Set keyboard delay, for key down and key up events, in
2279 milliseconds. Default is 10. Keyboards are low-bandwidth
2280 devices, so this slowdown can help the device and guest to keep
2281 up and not lose events in case events are arriving in bulk.
2282 Possible causes for the latter are flaky network connections, or
2283 scripts for automated testing.
2285 ``audiodev=audiodev``
2286 Use the specified audiodev when the VNC client requests audio
2287 transmission. When not using an -audiodev argument, this option
2288 must be omitted, otherwise is must be present and specify a
2289 valid audiodev.
2291 ``power-control=on|off``
2292 Permit the remote client to issue shutdown, reboot or reset power
2293 control requests.
2294 ERST
2296 ARCHHEADING(, QEMU_ARCH_I386)
2298 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2300 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2301 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2302 QEMU_ARCH_I386)
2303 SRST
2304 ``-win2k-hack``
2305 Use it when installing Windows 2000 to avoid a disk full bug. After
2306 Windows 2000 is installed, you no longer need this option (this
2307 option slows down the IDE transfers).
2308 ERST
2310 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2311 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2312 QEMU_ARCH_I386)
2313 SRST
2314 ``-no-fd-bootchk``
2315 Disable boot signature checking for floppy disks in BIOS. May be
2316 needed to boot from old floppy disks.
2317 ERST
2319 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2320 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2321 SRST
2322 ``-no-acpi``
2323 Disable ACPI (Advanced Configuration and Power Interface) support.
2324 Use it if your guest OS complains about ACPI problems (PC target
2325 machine only).
2326 ERST
2328 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2329 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2330 SRST
2331 ``-no-hpet``
2332 Disable HPET support.
2333 ERST
2335 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2336 "-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"
2337 " ACPI table description\n", QEMU_ARCH_I386)
2338 SRST
2339 ``-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]...]``
2340 Add ACPI table with specified header fields and context from
2341 specified files. For file=, take whole ACPI table from the specified
2342 files, including all ACPI headers (possible overridden by other
2343 options). For data=, only data portion of the table is used, all
2344 header information is specified in the command line. If a SLIC table
2345 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id
2346 fields will override the same in the RSDT and the FADT (a.k.a.
2347 FACP), in order to ensure the field matches required by the
2348 Microsoft SLIC spec and the ACPI spec.
2349 ERST
2351 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2352 "-smbios file=binary\n"
2353 " load SMBIOS entry from binary file\n"
2354 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2355 " [,uefi=on|off]\n"
2356 " specify SMBIOS type 0 fields\n"
2357 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2358 " [,uuid=uuid][,sku=str][,family=str]\n"
2359 " specify SMBIOS type 1 fields\n"
2360 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2361 " [,asset=str][,location=str]\n"
2362 " specify SMBIOS type 2 fields\n"
2363 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2364 " [,sku=str]\n"
2365 " specify SMBIOS type 3 fields\n"
2366 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2367 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
2368 " specify SMBIOS type 4 fields\n"
2369 "-smbios type=11[,value=str][,path=filename]\n"
2370 " specify SMBIOS type 11 fields\n"
2371 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2372 " [,asset=str][,part=str][,speed=%d]\n"
2373 " specify SMBIOS type 17 fields\n"
2374 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n"
2375 " specify SMBIOS type 41 fields\n",
2376 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2377 SRST
2378 ``-smbios file=binary``
2379 Load SMBIOS entry from binary file.
2381 ``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]``
2382 Specify SMBIOS type 0 fields
2384 ``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]``
2385 Specify SMBIOS type 1 fields
2387 ``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]``
2388 Specify SMBIOS type 2 fields
2390 ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
2391 Specify SMBIOS type 3 fields
2393 ``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]``
2394 Specify SMBIOS type 4 fields
2396 ``-smbios type=11[,value=str][,path=filename]``
2397 Specify SMBIOS type 11 fields
2399 This argument can be repeated multiple times, and values are added in the order they are parsed.
2400 Applications intending to use OEM strings data are encouraged to use their application name as
2401 a prefix for the value string. This facilitates passing information for multiple applications
2402 concurrently.
2404 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax
2405 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes.
2407 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to
2408 the SMBIOS table in the order in which they appear.
2410 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535
2411 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the
2412 guest. Instead it should be used as a indicator to inform the guest where to locate the real
2413 data set, for example, by specifying the serial ID of a block device.
2415 An example passing three strings is
2417 .. parsed-literal::
2419 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\
2420 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\
2421 path=/some/file/with/oemstringsdata.txt
2423 In the guest OS this is visible with the ``dmidecode`` command
2425 .. parsed-literal::
2427 $ dmidecode -t 11
2428 Handle 0x0E00, DMI type 11, 5 bytes
2429 OEM Strings
2430 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/
2431 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os
2432 String 3: myapp:some extra data
2435 ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
2436 Specify SMBIOS type 17 fields
2438 ``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]``
2439 Specify SMBIOS type 41 fields
2441 This argument can be repeated multiple times. Its main use is to allow network interfaces be created
2442 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface
2443 position on the PCI bus.
2445 Here is an example of use:
2447 .. parsed-literal::
2449 -netdev user,id=internet \\
2450 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\
2451 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev
2453 In the guest OS, the device should then appear as ``eno1``:
2455 ..parsed-literal::
2457 $ ip -brief l
2458 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
2459 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP>
2461 Currently, the PCI device has to be attached to the root bus.
2463 ERST
2465 DEFHEADING()
2467 DEFHEADING(Network options:)
2469 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2470 #ifdef CONFIG_SLIRP
2471 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n"
2472 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2473 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2474 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2475 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2476 #ifndef _WIN32
2477 "[,smb=dir[,smbserver=addr]]\n"
2478 #endif
2479 " configure a user mode network backend with ID 'str',\n"
2480 " its DHCP server and optional services\n"
2481 #endif
2482 #ifdef _WIN32
2483 "-netdev tap,id=str,ifname=name\n"
2484 " configure a host TAP network backend with ID 'str'\n"
2485 #else
2486 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2487 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2488 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2489 " [,poll-us=n]\n"
2490 " configure a host TAP network backend with ID 'str'\n"
2491 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2492 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2493 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2494 " to deconfigure it\n"
2495 " use '[down]script=no' to disable script execution\n"
2496 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2497 " configure it\n"
2498 " use 'fd=h' to connect to an already opened TAP interface\n"
2499 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2500 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2501 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2502 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2503 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2504 " use vhost=on to enable experimental in kernel accelerator\n"
2505 " (only has effect for virtio guests which use MSIX)\n"
2506 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2507 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2508 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2509 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2510 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n"
2511 " spent on busy polling for vhost net\n"
2512 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2513 " configure a host TAP network backend with ID 'str' that is\n"
2514 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2515 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2516 #endif
2517 #ifdef __linux__
2518 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2519 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n"
2520 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n"
2521 " [,rxcookie=rxcookie][,offset=offset]\n"
2522 " configure a network backend with ID 'str' connected to\n"
2523 " an Ethernet over L2TPv3 pseudowire.\n"
2524 " Linux kernel 3.3+ as well as most routers can talk\n"
2525 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2526 " VM to a router and even VM to Host. It is a nearly-universal\n"
2527 " standard (RFC3931). Note - this implementation uses static\n"
2528 " pre-configured tunnels (same as the Linux kernel).\n"
2529 " use 'src=' to specify source address\n"
2530 " use 'dst=' to specify destination address\n"
2531 " use 'udp=on' to specify udp encapsulation\n"
2532 " use 'srcport=' to specify source udp port\n"
2533 " use 'dstport=' to specify destination udp port\n"
2534 " use 'ipv6=on' to force v6\n"
2535 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2536 " well as a weak security measure\n"
2537 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2538 " use 'txcookie=0x012345678' to specify a txcookie\n"
2539 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2540 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2541 " use 'pincounter=on' to work around broken counter handling in peer\n"
2542 " use 'offset=X' to add an extra offset between header and data\n"
2543 #endif
2544 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2545 " configure a network backend to connect to another network\n"
2546 " using a socket connection\n"
2547 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2548 " configure a network backend to connect to a multicast maddr and port\n"
2549 " use 'localaddr=addr' to specify the host address to send packets from\n"
2550 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2551 " configure a network backend to connect to another network\n"
2552 " using an UDP tunnel\n"
2553 #ifdef CONFIG_VDE
2554 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2555 " configure a network backend to connect to port 'n' of a vde switch\n"
2556 " running on host and listening for incoming connections on 'socketpath'.\n"
2557 " Use group 'groupname' and mode 'octalmode' to change default\n"
2558 " ownership and permissions for communication port.\n"
2559 #endif
2560 #ifdef CONFIG_NETMAP
2561 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2562 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2563 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2564 " netmap device, defaults to '/dev/netmap')\n"
2565 #endif
2566 #ifdef CONFIG_POSIX
2567 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2568 " configure a vhost-user network, backed by a chardev 'dev'\n"
2569 #endif
2570 #ifdef __linux__
2571 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n"
2572 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n"
2573 #endif
2574 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2575 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2576 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2577 "-nic [tap|bridge|"
2578 #ifdef CONFIG_SLIRP
2579 "user|"
2580 #endif
2581 #ifdef __linux__
2582 "l2tpv3|"
2583 #endif
2584 #ifdef CONFIG_VDE
2585 "vde|"
2586 #endif
2587 #ifdef CONFIG_NETMAP
2588 "netmap|"
2589 #endif
2590 #ifdef CONFIG_POSIX
2591 "vhost-user|"
2592 #endif
2593 "socket][,option][,...][mac=macaddr]\n"
2594 " initialize an on-board / default host NIC (using MAC address\n"
2595 " macaddr) and connect it to the given host network backend\n"
2596 "-nic none use it alone to have zero network devices (the default is to\n"
2597 " provided a 'user' network connection)\n",
2598 QEMU_ARCH_ALL)
2599 DEF("net", HAS_ARG, QEMU_OPTION_net,
2600 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2601 " configure or create an on-board (or machine default) NIC and\n"
2602 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2603 "-net ["
2604 #ifdef CONFIG_SLIRP
2605 "user|"
2606 #endif
2607 "tap|"
2608 "bridge|"
2609 #ifdef CONFIG_VDE
2610 "vde|"
2611 #endif
2612 #ifdef CONFIG_NETMAP
2613 "netmap|"
2614 #endif
2615 "socket][,option][,option][,...]\n"
2616 " old way to initialize a host network interface\n"
2617 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2618 SRST
2619 ``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
2620 This option is a shortcut for configuring both the on-board
2621 (default) guest NIC hardware and the host network backend in one go.
2622 The host backend options are the same as with the corresponding
2623 ``-netdev`` options below. The guest NIC model can be set with
2624 ``model=modelname``. Use ``model=help`` to list the available device
2625 types. The hardware MAC address can be set with ``mac=macaddr``.
2627 The following two example do exactly the same, to show how ``-nic``
2628 can be used to shorten the command line length:
2630 .. parsed-literal::
2632 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2633 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2635 ``-nic none``
2636 Indicate that no network devices should be configured. It is used to
2637 override the default configuration (default NIC with "user" host
2638 network backend) which is activated if no other networking options
2639 are provided.
2641 ``-netdev user,id=id[,option][,option][,...]``
2642 Configure user mode host network backend which requires no
2643 administrator privilege to run. Valid options are:
2645 ``id=id``
2646 Assign symbolic name for use in monitor commands.
2648 ``ipv4=on|off and ipv6=on|off``
2649 Specify that either IPv4 or IPv6 must be enabled. If neither is
2650 specified both protocols are enabled.
2652 ``net=addr[/mask]``
2653 Set IP network address the guest will see. Optionally specify
2654 the netmask, either in the form a.b.c.d or as number of valid
2655 top-most bits. Default is 10.0.2.0/24.
2657 ``host=addr``
2658 Specify the guest-visible address of the host. Default is the
2659 2nd IP in the guest network, i.e. x.x.x.2.
2661 ``ipv6-net=addr[/int]``
2662 Set IPv6 network address the guest will see (default is
2663 fec0::/64). The network prefix is given in the usual hexadecimal
2664 IPv6 address notation. The prefix size is optional, and is given
2665 as the number of valid top-most bits (default is 64).
2667 ``ipv6-host=addr``
2668 Specify the guest-visible IPv6 address of the host. Default is
2669 the 2nd IPv6 in the guest network, i.e. xxxx::2.
2671 ``restrict=on|off``
2672 If this option is enabled, the guest will be isolated, i.e. it
2673 will not be able to contact the host and no guest IP packets
2674 will be routed over the host to the outside. This option does
2675 not affect any explicitly set forwarding rules.
2677 ``hostname=name``
2678 Specifies the client hostname reported by the built-in DHCP
2679 server.
2681 ``dhcpstart=addr``
2682 Specify the first of the 16 IPs the built-in DHCP server can
2683 assign. Default is the 15th to 31st IP in the guest network,
2684 i.e. x.x.x.15 to x.x.x.31.
2686 ``dns=addr``
2687 Specify the guest-visible address of the virtual nameserver. The
2688 address must be different from the host address. Default is the
2689 3rd IP in the guest network, i.e. x.x.x.3.
2691 ``ipv6-dns=addr``
2692 Specify the guest-visible address of the IPv6 virtual
2693 nameserver. The address must be different from the host address.
2694 Default is the 3rd IP in the guest network, i.e. xxxx::3.
2696 ``dnssearch=domain``
2697 Provides an entry for the domain-search list sent by the
2698 built-in DHCP server. More than one domain suffix can be
2699 transmitted by specifying this option multiple times. If
2700 supported, this will cause the guest to automatically try to
2701 append the given domain suffix(es) in case a domain name can not
2702 be resolved.
2704 Example:
2706 .. parsed-literal::
2708 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2710 ``domainname=domain``
2711 Specifies the client domain name reported by the built-in DHCP
2712 server.
2714 ``tftp=dir``
2715 When using the user mode network stack, activate a built-in TFTP
2716 server. The files in dir will be exposed as the root of a TFTP
2717 server. The TFTP client on the guest must be configured in
2718 binary mode (use the command ``bin`` of the Unix TFTP client).
2720 ``tftp-server-name=name``
2721 In BOOTP reply, broadcast name as the "TFTP server name"
2722 (RFC2132 option 66). This can be used to advise the guest to
2723 load boot files or configurations from a different server than
2724 the host address.
2726 ``bootfile=file``
2727 When using the user mode network stack, broadcast file as the
2728 BOOTP filename. In conjunction with ``tftp``, this can be used
2729 to network boot a guest from a local directory.
2731 Example (using pxelinux):
2733 .. parsed-literal::
2735 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\
2736 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2738 ``smb=dir[,smbserver=addr]``
2739 When using the user mode network stack, activate a built-in SMB
2740 server so that Windows OSes can access to the host files in
2741 ``dir`` transparently. The IP address of the SMB server can be
2742 set to addr. By default the 4th IP in the guest network is used,
2743 i.e. x.x.x.4.
2745 In the guest Windows OS, the line:
2749 10.0.2.4 smbserver
2751 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
2752 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
2753 NT/2000).
2755 Then ``dir`` can be accessed in ``\\smbserver\qemu``.
2757 Note that a SAMBA server must be installed on the host OS.
2759 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport``
2760 Redirect incoming TCP or UDP connections to the host port
2761 hostport to the guest IP address guestaddr on guest port
2762 guestport. If guestaddr is not specified, its value is x.x.x.15
2763 (default first address given by the built-in DHCP server). By
2764 specifying hostaddr, the rule can be bound to a specific host
2765 interface. If no connection type is set, TCP is used. This
2766 option can be given multiple times.
2768 For example, to redirect host X11 connection from screen 1 to
2769 guest screen 0, use the following:
2771 .. parsed-literal::
2773 # on the host
2774 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2775 # this host xterm should open in the guest X11 server
2776 xterm -display :1
2778 To redirect telnet connections from host port 5555 to telnet
2779 port on the guest, use the following:
2781 .. parsed-literal::
2783 # on the host
2784 |qemu_system| -nic user,hostfwd=tcp::5555-:23
2785 telnet localhost 5555
2787 Then when you use on the host ``telnet localhost 5555``, you
2788 connect to the guest telnet server.
2790 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command``
2791 Forward guest TCP connections to the IP address server on port
2792 port to the character device dev or to a program executed by
2793 cmd:command which gets spawned for each connection. This option
2794 can be given multiple times.
2796 You can either use a chardev directly and have that one used
2797 throughout QEMU's lifetime, like in the following example:
2799 .. parsed-literal::
2801 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2802 # the guest accesses it
2803 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2805 Or you can execute a command on every TCP connection established
2806 by the guest, so that QEMU behaves similar to an inetd process
2807 for that virtual server:
2809 .. parsed-literal::
2811 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2812 # and connect the TCP stream to its stdin/stdout
2813 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2815 ``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]``
2816 Configure a host TAP network backend with ID id.
2818 Use the network script file to configure it and the network script
2819 dfile to deconfigure it. If name is not provided, the OS
2820 automatically provides one. The default network configure script is
2821 ``/etc/qemu-ifup`` and the default network deconfigure script is
2822 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to
2823 disable script execution.
2825 If running QEMU as an unprivileged user, use the network helper
2826 to configure the TAP interface and attach it to the bridge.
2827 The default network helper executable is
2828 ``/path/to/qemu-bridge-helper`` and the default bridge device is
2829 ``br0``.
2831 ``fd``\ =h can be used to specify the handle of an already opened
2832 host TAP interface.
2834 Examples:
2836 .. parsed-literal::
2838 #launch a QEMU instance with the default network script
2839 |qemu_system| linux.img -nic tap
2841 .. parsed-literal::
2843 #launch a QEMU instance with two NICs, each one connected
2844 #to a TAP device
2845 |qemu_system| linux.img \\
2846 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\
2847 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2849 .. parsed-literal::
2851 #launch a QEMU instance with the default network helper to
2852 #connect a TAP device to bridge br0
2853 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
2854 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2856 ``-netdev bridge,id=id[,br=bridge][,helper=helper]``
2857 Connect a host TAP network interface to a host bridge device.
2859 Use the network helper helper to configure the TAP interface and
2860 attach it to the bridge. The default network helper executable is
2861 ``/path/to/qemu-bridge-helper`` and the default bridge device is
2862 ``br0``.
2864 Examples:
2866 .. parsed-literal::
2868 #launch a QEMU instance with the default network helper to
2869 #connect a TAP device to bridge br0
2870 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2872 .. parsed-literal::
2874 #launch a QEMU instance with the default network helper to
2875 #connect a TAP device to bridge qemubr0
2876 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2878 ``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]``
2879 This host network backend can be used to connect the guest's network
2880 to another QEMU virtual machine using a TCP socket connection. If
2881 ``listen`` is specified, QEMU waits for incoming connections on port
2882 (host is optional). ``connect`` is used to connect to another QEMU
2883 instance using the ``listen`` option. ``fd``\ =h specifies an
2884 already opened TCP socket.
2886 Example:
2888 .. parsed-literal::
2890 # launch a first QEMU instance
2891 |qemu_system| linux.img \\
2892 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2893 -netdev socket,id=n1,listen=:1234
2894 # connect the network of this instance to the network of the first instance
2895 |qemu_system| linux.img \\
2896 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
2897 -netdev socket,id=n2,connect=127.0.0.1:1234
2899 ``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]``
2900 Configure a socket host network backend to share the guest's network
2901 traffic with another QEMU virtual machines using a UDP multicast
2902 socket, effectively making a bus for every QEMU with same multicast
2903 address maddr and port. NOTES:
2905 1. Several QEMU can be running on different hosts and share same bus
2906 (assuming correct multicast setup for these hosts).
2908 2. mcast support is compatible with User Mode Linux (argument
2909 ``ethN=mcast``), see http://user-mode-linux.sf.net.
2911 3. Use ``fd=h`` to specify an already opened UDP multicast socket.
2913 Example:
2915 .. parsed-literal::
2917 # launch one QEMU instance
2918 |qemu_system| linux.img \\
2919 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2920 -netdev socket,id=n1,mcast=230.0.0.1:1234
2921 # launch another QEMU instance on same "bus"
2922 |qemu_system| linux.img \\
2923 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
2924 -netdev socket,id=n2,mcast=230.0.0.1:1234
2925 # launch yet another QEMU instance on same "bus"
2926 |qemu_system| linux.img \\
2927 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\
2928 -netdev socket,id=n3,mcast=230.0.0.1:1234
2930 Example (User Mode Linux compat.):
2932 .. parsed-literal::
2934 # launch QEMU instance (note mcast address selected is UML's default)
2935 |qemu_system| linux.img \\
2936 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2937 -netdev socket,id=n1,mcast=239.192.168.1:1102
2938 # launch UML
2939 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2941 Example (send packets from host's 1.2.3.4):
2943 .. parsed-literal::
2945 |qemu_system| linux.img \\
2946 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2947 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2949 ``-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]``
2950 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
2951 is a popular protocol to transport Ethernet (and other Layer 2) data
2952 frames between two systems. It is present in routers, firewalls and
2953 the Linux kernel (from version 3.3 onwards).
2955 This transport allows a VM to communicate to another VM, router or
2956 firewall directly.
2958 ``src=srcaddr``
2959 source address (mandatory)
2961 ``dst=dstaddr``
2962 destination address (mandatory)
2964 ``udp``
2965 select udp encapsulation (default is ip).
2967 ``srcport=srcport``
2968 source udp port.
2970 ``dstport=dstport``
2971 destination udp port.
2973 ``ipv6``
2974 force v6, otherwise defaults to v4.
2976 ``rxcookie=rxcookie``; \ ``txcookie=txcookie``
2977 Cookies are a weak form of security in the l2tpv3 specification.
2978 Their function is mostly to prevent misconfiguration. By default
2979 they are 32 bit.
2981 ``cookie64``
2982 Set cookie size to 64 bit instead of the default 32
2984 ``counter=off``
2985 Force a 'cut-down' L2TPv3 with no counter as in
2986 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2988 ``pincounter=on``
2989 Work around broken counter handling in peer. This may also help
2990 on networks which have packet reorder.
2992 ``offset=offset``
2993 Add an extra offset between header and data
2995 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to
2996 the bridge br-lan on the remote Linux host 1.2.3.4:
2998 .. parsed-literal::
3000 # Setup tunnel on linux host using raw ip as encapsulation
3001 # on 1.2.3.4
3002 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\
3003 encap udp udp_sport 16384 udp_dport 16384
3004 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\
3005 0xFFFFFFFF peer_session_id 0xFFFFFFFF
3006 ifconfig vmtunnel0 mtu 1500
3007 ifconfig vmtunnel0 up
3008 brctl addif br-lan vmtunnel0
3011 # on 4.3.2.1
3012 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
3014 |qemu_system| linux.img -device e1000,netdev=n1 \\
3015 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
3017 ``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]``
3018 Configure VDE backend to connect to PORT n of a vde switch running
3019 on host and listening for incoming connections on socketpath. Use
3020 GROUP groupname and MODE octalmode to change default ownership and
3021 permissions for communication port. This option is only available if
3022 QEMU has been compiled with vde support enabled.
3024 Example:
3026 .. parsed-literal::
3028 # launch vde switch
3029 vde_switch -F -sock /tmp/myswitch
3030 # launch QEMU instance
3031 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch
3033 ``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
3034 Establish a vhost-user netdev, backed by a chardev id. The chardev
3035 should be a unix domain socket backed one. The vhost-user uses a
3036 specifically defined protocol to pass vhost ioctl replacement
3037 messages to an application on the other end of the socket. On
3038 non-MSIX guests, the feature can be forced with vhostforce. Use
3039 'queues=n' to specify the number of queues to be created for
3040 multiqueue vhost-user.
3042 Example:
3046 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
3047 -numa node,memdev=mem \
3048 -chardev socket,id=chr0,path=/path/to/socket \
3049 -netdev type=vhost-user,id=net0,chardev=chr0 \
3050 -device virtio-net-pci,netdev=net0
3052 ``-netdev vhost-vdpa,vhostdev=/path/to/dev``
3053 Establish a vhost-vdpa netdev.
3055 vDPA device is a device that uses a datapath which complies with
3056 the virtio specifications with a vendor specific control path.
3057 vDPA devices can be both physically located on the hardware or
3058 emulated by software.
3060 ``-netdev hubport,id=id,hubid=hubid[,netdev=nd]``
3061 Create a hub port on the emulated hub with ID hubid.
3063 The hubport netdev lets you connect a NIC to a QEMU emulated hub
3064 instead of a single netdev. Alternatively, you can also connect the
3065 hubport to another netdev with ID nd by using the ``netdev=nd``
3066 option.
3068 ``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]``
3069 Legacy option to configure or create an on-board (or machine
3070 default) Network Interface Card(NIC) and connect it either to the
3071 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd.
3072 If model is omitted, then the default NIC model associated with the
3073 machine type is used. Note that the default NIC model may change in
3074 future QEMU releases, so it is highly recommended to always specify
3075 a model. Optionally, the MAC address can be changed to mac, the
3076 device address set to addr (PCI cards only), and a name can be
3077 assigned for use in monitor commands. Optionally, for PCI cards, you
3078 can specify the number v of MSI-X vectors that the card should have;
3079 this option currently only affects virtio cards; set v = 0 to
3080 disable MSI-X. If no ``-net`` option is specified, a single NIC is
3081 created. QEMU can emulate several different models of network card.
3082 Use ``-net nic,model=help`` for a list of available devices for your
3083 target.
3085 ``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]``
3086 Configure a host network backend (with the options corresponding to
3087 the same ``-netdev`` option) and connect it to the emulated hub 0
3088 (the default hub). Use name to specify the name of the hub port.
3089 ERST
3091 DEFHEADING()
3093 DEFHEADING(Character device options:)
3095 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
3096 "-chardev help\n"
3097 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3098 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n"
3099 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
3100 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
3101 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
3102 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n"
3103 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
3104 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
3105 " [,logfile=PATH][,logappend=on|off]\n"
3106 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3107 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
3108 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3109 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
3110 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3111 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3112 #ifdef _WIN32
3113 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3114 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3115 #else
3116 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3117 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
3118 #endif
3119 #ifdef CONFIG_BRLAPI
3120 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3121 #endif
3122 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
3123 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
3124 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3125 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3126 #endif
3127 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
3128 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3129 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3130 #endif
3131 #if defined(CONFIG_SPICE)
3132 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3133 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3134 #endif
3135 , QEMU_ARCH_ALL
3138 SRST
3139 The general form of a character device option is:
3141 ``-chardev backend,id=id[,mux=on|off][,options]``
3142 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``,
3143 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``,
3144 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``,
3145 ``spicevmc``, ``spiceport``. The specific backend will determine the
3146 applicable options.
3148 Use ``-chardev help`` to print all available chardev backend types.
3150 All devices must have an id, which can be any string up to 127
3151 characters long. It is used to uniquely identify this device in
3152 other command line directives.
3154 A character device may be used in multiplexing mode by multiple
3155 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is
3156 a "1:N" device, and here the "1" end is your specified chardev
3157 backend, and the "N" end is the various parts of QEMU that can talk
3158 to a chardev. If you create a chardev with ``id=myid`` and
3159 ``mux=on``, QEMU will create a multiplexer with your specified ID,
3160 and you can then configure multiple front ends to use that chardev
3161 ID for their input/output. Up to four different front ends can be
3162 connected to a single multiplexed chardev. (Without multiplexing
3163 enabled, a chardev can only be used by a single front end.) For
3164 instance you could use this to allow a single stdio chardev to be
3165 used by two serial ports and the QEMU monitor:
3169 -chardev stdio,mux=on,id=char0 \
3170 -mon chardev=char0,mode=readline \
3171 -serial chardev:char0 \
3172 -serial chardev:char0
3174 You can have more than one multiplexer in a system configuration;
3175 for instance you could have a TCP port multiplexed between UART 0
3176 and UART 1, and stdio multiplexed between the QEMU monitor and a
3177 parallel port:
3181 -chardev stdio,mux=on,id=char0 \
3182 -mon chardev=char0,mode=readline \
3183 -parallel chardev:char0 \
3184 -chardev tcp,...,mux=on,id=char1 \
3185 -serial chardev:char1 \
3186 -serial chardev:char1
3188 When you're using a multiplexed character device, some escape
3189 sequences are interpreted in the input. See the chapter about
3190 :ref:`keys in the character backend multiplexer` in the
3191 System Emulation Users Guide for more details.
3193 Note that some other command line options may implicitly create
3194 multiplexed character backends; for instance ``-serial mon:stdio``
3195 creates a multiplexed stdio backend connected to the serial port and
3196 the QEMU monitor, and ``-nographic`` also multiplexes the console
3197 and the monitor to stdio.
3199 There is currently no support for multiplexing in the other
3200 direction (where a single QEMU front end takes input and output from
3201 multiple chardevs).
3203 Every backend supports the ``logfile`` option, which supplies the
3204 path to a file to record all data transmitted via the backend. The
3205 ``logappend`` option controls whether the log file will be truncated
3206 or appended to when opened.
3208 The available backends are:
3210 ``-chardev null,id=id``
3211 A void device. This device will not emit any data, and will drop any
3212 data it receives. The null backend does not take any options.
3214 ``-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]``
3215 Create a two-way stream socket, which can be either a TCP or a unix
3216 socket. A unix socket will be created if ``path`` is specified.
3217 Behaviour is undefined if TCP options are specified for a unix
3218 socket.
3220 ``server=on|off`` specifies that the socket shall be a listening socket.
3222 ``wait=on|off`` specifies that QEMU should not block waiting for a client
3223 to connect to a listening socket.
3225 ``telnet=on|off`` specifies that traffic on the socket should interpret
3226 telnet escape sequences.
3228 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for
3229 communication.
3231 ``reconnect`` sets the timeout for reconnecting on non-server
3232 sockets when the remote end goes away. qemu will delay this many
3233 seconds and then attempt to reconnect. Zero disables reconnecting,
3234 and is the default.
3236 ``tls-creds`` requests enablement of the TLS protocol for
3237 encryption, and specifies the id of the TLS credentials to use for
3238 the handshake. The credentials must be previously created with the
3239 ``-object tls-creds`` argument.
3241 ``tls-auth`` provides the ID of the QAuthZ authorization object
3242 against which the client's x509 distinguished name will be
3243 validated. This object is only resolved at time of use, so can be
3244 deleted and recreated on the fly while the chardev server is active.
3245 If missing, it will default to denying access.
3247 TCP and unix socket options are given below:
3249 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]``
3250 ``host`` for a listening socket specifies the local address to
3251 be bound. For a connecting socket species the remote host to
3252 connect to. ``host`` is optional for listening sockets. If not
3253 specified it defaults to ``0.0.0.0``.
3255 ``port`` for a listening socket specifies the local port to be
3256 bound. For a connecting socket specifies the port on the remote
3257 host to connect to. ``port`` can be given as either a port
3258 number or a service name. ``port`` is required.
3260 ``to`` is only relevant to listening sockets. If it is
3261 specified, and ``port`` cannot be bound, QEMU will attempt to
3262 bind to subsequent ports up to and including ``to`` until it
3263 succeeds. ``to`` must be specified as a port number.
3265 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4
3266 or IPv6 must be used. If neither is specified the socket may
3267 use either protocol.
3269 ``nodelay=on|off`` disables the Nagle algorithm.
3271 ``unix options: path=path[,abstract=on|off][,tight=on|off]``
3272 ``path`` specifies the local path of the unix socket. ``path``
3273 is required.
3274 ``abstract=on|off`` specifies the use of the abstract socket namespace,
3275 rather than the filesystem. Optional, defaults to false.
3276 ``tight=on|off`` sets the socket length of abstract sockets to their minimum,
3277 rather than the full sun_path length. Optional, defaults to true.
3279 ``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]``
3280 Sends all traffic from the guest to a remote host over UDP.
3282 ``host`` specifies the remote host to connect to. If not specified
3283 it defaults to ``localhost``.
3285 ``port`` specifies the port on the remote host to connect to.
3286 ``port`` is required.
3288 ``localaddr`` specifies the local address to bind to. If not
3289 specified it defaults to ``0.0.0.0``.
3291 ``localport`` specifies the local port to bind to. If not specified
3292 any available local port will be used.
3294 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used.
3295 If neither is specified the device may use either protocol.
3297 ``-chardev msmouse,id=id``
3298 Forward QEMU's emulated msmouse events to the guest. ``msmouse``
3299 does not take any options.
3301 ``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]``
3302 Connect to a QEMU text console. ``vc`` may optionally be given a
3303 specific size.
3305 ``width`` and ``height`` specify the width and height respectively
3306 of the console, in pixels.
3308 ``cols`` and ``rows`` specify that the console be sized to fit a
3309 text console with the given dimensions.
3311 ``-chardev ringbuf,id=id[,size=size]``
3312 Create a ring buffer with fixed size ``size``. size must be a power
3313 of two and defaults to ``64K``.
3315 ``-chardev file,id=id,path=path``
3316 Log all traffic received from the guest to a file.
3318 ``path`` specifies the path of the file to be opened. This file will
3319 be created if it does not already exist, and overwritten if it does.
3320 ``path`` is required.
3322 ``-chardev pipe,id=id,path=path``
3323 Create a two-way connection to the guest. The behaviour differs
3324 slightly between Windows hosts and other hosts:
3326 On Windows, a single duplex pipe will be created at
3327 ``\\.pipe\path``.
3329 On other hosts, 2 pipes will be created called ``path.in`` and
3330 ``path.out``. Data written to ``path.in`` will be received by the
3331 guest. Data written by the guest can be read from ``path.out``. QEMU
3332 will not create these fifos, and requires them to be present.
3334 ``path`` forms part of the pipe path as described above. ``path`` is
3335 required.
3337 ``-chardev console,id=id``
3338 Send traffic from the guest to QEMU's standard output. ``console``
3339 does not take any options.
3341 ``console`` is only available on Windows hosts.
3343 ``-chardev serial,id=id,path=path``
3344 Send traffic from the guest to a serial device on the host.
3346 On Unix hosts serial will actually accept any tty device, not only
3347 serial lines.
3349 ``path`` specifies the name of the serial device to open.
3351 ``-chardev pty,id=id``
3352 Create a new pseudo-terminal on the host and connect to it. ``pty``
3353 does not take any options.
3355 ``pty`` is not available on Windows hosts.
3357 ``-chardev stdio,id=id[,signal=on|off]``
3358 Connect to standard input and standard output of the QEMU process.
3360 ``signal`` controls if signals are enabled on the terminal, that
3361 includes exiting QEMU with the key sequence Control-c. This option
3362 is enabled by default, use ``signal=off`` to disable it.
3364 ``-chardev braille,id=id``
3365 Connect to a local BrlAPI server. ``braille`` does not take any
3366 options.
3368 ``-chardev tty,id=id,path=path``
3369 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD
3370 and DragonFlyBSD hosts. It is an alias for ``serial``.
3372 ``path`` specifies the path to the tty. ``path`` is required.
3374 ``-chardev parallel,id=id,path=path``
3376 ``-chardev parport,id=id,path=path``
3377 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD
3378 hosts.
3380 Connect to a local parallel port.
3382 ``path`` specifies the path to the parallel port device. ``path`` is
3383 required.
3385 ``-chardev spicevmc,id=id,debug=debug,name=name``
3386 ``spicevmc`` is only available when spice support is built in.
3388 ``debug`` debug level for spicevmc
3390 ``name`` name of spice channel to connect to
3392 Connect to a spice virtual machine channel, such as vdiport.
3394 ``-chardev spiceport,id=id,debug=debug,name=name``
3395 ``spiceport`` is only available when spice support is built in.
3397 ``debug`` debug level for spicevmc
3399 ``name`` name of spice port to connect to
3401 Connect to a spice port, allowing a Spice client to handle the
3402 traffic identified by a name (preferably a fqdn).
3403 ERST
3405 DEFHEADING()
3407 #ifdef CONFIG_TPM
3408 DEFHEADING(TPM device options:)
3410 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3411 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3412 " use path to provide path to a character device; default is /dev/tpm0\n"
3413 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3414 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3415 "-tpmdev emulator,id=id,chardev=dev\n"
3416 " configure the TPM device using chardev backend\n",
3417 QEMU_ARCH_ALL)
3418 SRST
3419 The general form of a TPM device option is:
3421 ``-tpmdev backend,id=id[,options]``
3422 The specific backend type will determine the applicable options. The
3423 ``-tpmdev`` option creates the TPM backend and requires a
3424 ``-device`` option that specifies the TPM frontend interface model.
3426 Use ``-tpmdev help`` to print all available TPM backend types.
3428 The available backends are:
3430 ``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path``
3431 (Linux-host only) Enable access to the host's TPM using the
3432 passthrough driver.
3434 ``path`` specifies the path to the host's TPM device, i.e., on a
3435 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by
3436 default ``/dev/tpm0`` is used.
3438 ``cancel-path`` specifies the path to the host TPM device's sysfs
3439 entry allowing for cancellation of an ongoing TPM command.
3440 ``cancel-path`` is optional and by default QEMU will search for the
3441 sysfs entry to use.
3443 Some notes about using the host's TPM with the passthrough driver:
3445 The TPM device accessed by the passthrough driver must not be used
3446 by any other application on the host.
3448 Since the host's firmware (BIOS/UEFI) has already initialized the
3449 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize
3450 the TPM again and may therefore not show a TPM-specific menu that
3451 would otherwise allow the user to configure the TPM, e.g., allow the
3452 user to enable/disable or activate/deactivate the TPM. Further, if
3453 TPM ownership is released from within a VM then the host's TPM will
3454 get disabled and deactivated. To enable and activate the TPM again
3455 afterwards, the host has to be rebooted and the user is required to
3456 enter the firmware's menu to enable and activate the TPM. If the TPM
3457 is left disabled and/or deactivated most TPM commands will fail.
3459 To create a passthrough TPM use the following two options:
3463 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3465 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by
3466 ``tpmdev=tpm0`` in the device option.
3468 ``-tpmdev emulator,id=id,chardev=dev``
3469 (Linux-host only) Enable access to a TPM emulator using Unix domain
3470 socket based chardev backend.
3472 ``chardev`` specifies the unique ID of a character device backend
3473 that provides connection to the software TPM server.
3475 To create a TPM emulator backend device with chardev socket backend:
3479 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3480 ERST
3482 DEFHEADING()
3484 #endif
3486 DEFHEADING(Linux/Multiboot boot specific:)
3487 SRST
3488 When using these options, you can use a given Linux or Multiboot kernel
3489 without installing it in the disk image. It can be useful for easier
3490 testing of various kernels.
3493 ERST
3495 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3496 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3497 SRST
3498 ``-kernel bzImage``
3499 Use bzImage as kernel image. The kernel can be either a Linux kernel
3500 or in multiboot format.
3501 ERST
3503 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3504 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3505 SRST
3506 ``-append cmdline``
3507 Use cmdline as kernel command line
3508 ERST
3510 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3511 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3512 SRST
3513 ``-initrd file``
3514 Use file as initial ram disk.
3516 ``-initrd "file1 arg=foo,file2"``
3517 This syntax is only available with multiboot.
3519 Use file1 and file2 as modules and pass arg=foo as parameter to the
3520 first module.
3521 ERST
3523 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3524 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3525 SRST
3526 ``-dtb file``
3527 Use file as a device tree binary (dtb) image and pass it to the
3528 kernel on boot.
3529 ERST
3531 DEFHEADING()
3533 DEFHEADING(Debug/Expert options:)
3535 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
3536 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
3537 " Policy for handling deprecated management interfaces\n",
3538 QEMU_ARCH_ALL)
3539 SRST
3540 ``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]``
3541 Set policy for handling deprecated management interfaces (experimental):
3543 ``deprecated-input=accept`` (default)
3544 Accept deprecated commands and arguments
3545 ``deprecated-input=reject``
3546 Reject deprecated commands and arguments
3547 ``deprecated-input=crash``
3548 Crash on deprecated commands and arguments
3549 ``deprecated-output=accept`` (default)
3550 Emit deprecated command results and events
3551 ``deprecated-output=hide``
3552 Suppress deprecated command results and events
3554 Limitation: covers only syntactic aspects of QMP.
3555 ERST
3557 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3558 "-fw_cfg [name=]<name>,file=<file>\n"
3559 " add named fw_cfg entry with contents from file\n"
3560 "-fw_cfg [name=]<name>,string=<str>\n"
3561 " add named fw_cfg entry with contents from string\n",
3562 QEMU_ARCH_ALL)
3563 SRST
3564 ``-fw_cfg [name=]name,file=file``
3565 Add named fw\_cfg entry with contents from file file.
3567 ``-fw_cfg [name=]name,string=str``
3568 Add named fw\_cfg entry with contents from string str.
3570 The terminating NUL character of the contents of str will not be
3571 included as part of the fw\_cfg item data. To insert contents with
3572 embedded NUL characters, you have to use the file parameter.
3574 The fw\_cfg entries are passed by QEMU through to the guest.
3576 Example:
3580 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3582 creates an fw\_cfg entry named opt/com.mycompany/blob with contents
3583 from ./my\_blob.bin.
3584 ERST
3586 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3587 "-serial dev redirect the serial port to char device 'dev'\n",
3588 QEMU_ARCH_ALL)
3589 SRST
3590 ``-serial dev``
3591 Redirect the virtual serial port to host character device dev. The
3592 default device is ``vc`` in graphical mode and ``stdio`` in non
3593 graphical mode.
3595 This option can be used several times to simulate up to 4 serial
3596 ports.
3598 Use ``-serial none`` to disable all serial ports.
3600 Available character devices are:
3602 ``vc[:WxH]``
3603 Virtual console. Optionally, a width and height can be given in
3604 pixel with
3608 vc:800x600
3610 It is also possible to specify width or height in characters:
3614 vc:80Cx24C
3616 ``pty``
3617 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3619 ``none``
3620 No device is allocated.
3622 ``null``
3623 void device
3625 ``chardev:id``
3626 Use a named character device defined with the ``-chardev``
3627 option.
3629 ``/dev/XXX``
3630 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial
3631 port parameters are set according to the emulated ones.
3633 ``/dev/parportN``
3634 [Linux only, parallel port only] Use host parallel port N.
3635 Currently SPP and EPP parallel port features can be used.
3637 ``file:filename``
3638 Write output to filename. No character can be read.
3640 ``stdio``
3641 [Unix only] standard input/output
3643 ``pipe:filename``
3644 name pipe filename
3646 ``COMn``
3647 [Windows only] Use host serial port n
3649 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]``
3650 This implements UDP Net Console. When remote\_host or src\_ip
3651 are not specified they default to ``0.0.0.0``. When not using a
3652 specified src\_port a random port is automatically chosen.
3654 If you just want a simple readonly console you can use
3655 ``netcat`` or ``nc``, by starting QEMU with:
3656 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time
3657 QEMU writes something to that port it will appear in the
3658 netconsole session.
3660 If you plan to send characters back via netconsole or you want
3661 to stop and start QEMU a lot of times, you should have QEMU use
3662 the same source port each time by using something like ``-serial
3663 udp::4555@:4556`` to QEMU. Another approach is to use a patched
3664 version of netcat which can listen to a TCP port and send and
3665 receive characters via udp. If you have a patched version of
3666 netcat which activates telnet remote echo and single char
3667 transfer, then you can use the following options to set up a
3668 netcat redirector to allow telnet on port 5555 to access the
3669 QEMU port.
3671 ``QEMU Options:``
3672 -serial udp::4555@:4556
3674 ``netcat options:``
3675 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3677 ``telnet options:``
3678 localhost 5555
3680 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]``
3681 The TCP Net Console has two modes of operation. It can send the
3682 serial I/O to a location or wait for a connection from a
3683 location. By default the TCP Net Console is sent to host at the
3684 port. If you use the ``server=on`` option QEMU will wait for a client
3685 socket application to connect to the port before continuing,
3686 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off``
3687 option disables the Nagle buffering algorithm. The ``reconnect=on``
3688 option only applies if ``server=no`` is set, if the connection goes
3689 down it will attempt to reconnect at the given interval. If host
3690 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a
3691 time is accepted. You can use ``telnet=on`` to connect to the
3692 corresponding character device.
3694 ``Example to send tcp console to 192.168.0.2 port 4444``
3695 -serial tcp:192.168.0.2:4444
3697 ``Example to listen and wait on port 4444 for connection``
3698 -serial tcp::4444,server=on
3700 ``Example to not wait and listen on ip 192.168.0.100 port 4444``
3701 -serial tcp:192.168.0.100:4444,server=on,wait=off
3703 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]``
3704 The telnet protocol is used instead of raw tcp sockets. The
3705 options work the same as if you had specified ``-serial tcp``.
3706 The difference is that the port acts like a telnet server or
3707 client using telnet option negotiation. This will also allow you
3708 to send the MAGIC\_SYSRQ sequence if you use a telnet that
3709 supports sending the break sequence. Typically in unix telnet
3710 you do it with Control-] and then type "send break" followed by
3711 pressing the enter key.
3713 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]``
3714 The WebSocket protocol is used instead of raw tcp socket. The
3715 port acts as a WebSocket server. Client mode is not supported.
3717 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]``
3718 A unix domain socket is used instead of a tcp socket. The option
3719 works the same as if you had specified ``-serial tcp`` except
3720 the unix domain socket path is used for connections.
3722 ``mon:dev_string``
3723 This is a special option to allow the monitor to be multiplexed
3724 onto another serial port. The monitor is accessed with key
3725 sequence of Control-a and then pressing c. dev\_string should be
3726 any one of the serial devices specified above. An example to
3727 multiplex the monitor onto a telnet server listening on port
3728 4444 would be:
3730 ``-serial mon:telnet::4444,server=on,wait=off``
3732 When the monitor is multiplexed to stdio in this way, Ctrl+C
3733 will not terminate QEMU any more but will be passed to the guest
3734 instead.
3736 ``braille``
3737 Braille device. This will use BrlAPI to display the braille
3738 output on a real or fake device.
3740 ``msmouse``
3741 Three button serial mouse. Configure the guest to use Microsoft
3742 protocol.
3743 ERST
3745 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3746 "-parallel dev redirect the parallel port to char device 'dev'\n",
3747 QEMU_ARCH_ALL)
3748 SRST
3749 ``-parallel dev``
3750 Redirect the virtual parallel port to host device dev (same devices
3751 as the serial port). On Linux hosts, ``/dev/parportN`` can be used
3752 to use hardware devices connected on the corresponding host parallel
3753 port.
3755 This option can be used several times to simulate up to 3 parallel
3756 ports.
3758 Use ``-parallel none`` to disable all parallel ports.
3759 ERST
3761 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3762 "-monitor dev redirect the monitor to char device 'dev'\n",
3763 QEMU_ARCH_ALL)
3764 SRST
3765 ``-monitor dev``
3766 Redirect the monitor to host device dev (same devices as the serial
3767 port). The default device is ``vc`` in graphical mode and ``stdio``
3768 in non graphical mode. Use ``-monitor none`` to disable the default
3769 monitor.
3770 ERST
3771 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3772 "-qmp dev like -monitor but opens in 'control' mode\n",
3773 QEMU_ARCH_ALL)
3774 SRST
3775 ``-qmp dev``
3776 Like -monitor but opens in 'control' mode.
3777 ERST
3778 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3779 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3780 QEMU_ARCH_ALL)
3781 SRST
3782 ``-qmp-pretty dev``
3783 Like -qmp but uses pretty JSON formatting.
3784 ERST
3786 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3787 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3788 SRST
3789 ``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
3790 Setup monitor on chardev name. ``pretty`` is only valid when
3791 ``mode=control``, turning on JSON pretty printing to ease
3792 human reading and debugging.
3793 ERST
3795 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3796 "-debugcon dev redirect the debug console to char device 'dev'\n",
3797 QEMU_ARCH_ALL)
3798 SRST
3799 ``-debugcon dev``
3800 Redirect the debug console to host device dev (same devices as the
3801 serial port). The debug console is an I/O port which is typically
3802 port 0xe9; writing to that I/O port sends output to this device. The
3803 default device is ``vc`` in graphical mode and ``stdio`` in non
3804 graphical mode.
3805 ERST
3807 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3808 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
3809 SRST
3810 ``-pidfile file``
3811 Store the QEMU process PID in file. It is useful if you launch QEMU
3812 from a script.
3813 ERST
3815 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3816 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL)
3817 SRST
3818 ``-singlestep``
3819 Run the emulation in single step mode.
3820 ERST
3822 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3823 "--preconfig pause QEMU before machine is initialized (experimental)\n",
3824 QEMU_ARCH_ALL)
3825 SRST
3826 ``--preconfig``
3827 Pause QEMU for interactive configuration before the machine is
3828 created, which allows querying and configuring properties that will
3829 affect machine initialization. Use QMP command 'x-exit-preconfig' to
3830 exit the preconfig state and move to the next state (i.e. run guest
3831 if -S isn't used or pause the second time if -S is used). This
3832 option is experimental.
3833 ERST
3835 DEF("S", 0, QEMU_OPTION_S, \
3836 "-S freeze CPU at startup (use 'c' to start execution)\n",
3837 QEMU_ARCH_ALL)
3838 SRST
3839 ``-S``
3840 Do not start CPU at startup (you must type 'c' in the monitor).
3841 ERST
3843 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3844 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3845 " run qemu with overcommit hints\n"
3846 " mem-lock=on|off controls memory lock support (default: off)\n"
3847 " cpu-pm=on|off controls cpu power management (default: off)\n",
3848 QEMU_ARCH_ALL)
3849 SRST
3850 ``-overcommit mem-lock=on|off``
3852 ``-overcommit cpu-pm=on|off``
3853 Run qemu with hints about host resource overcommit. The default is
3854 to assume that host overcommits all resources.
3856 Locking qemu and guest memory can be enabled via ``mem-lock=on``
3857 (disabled by default). This works when host memory is not
3858 overcommitted and reduces the worst-case latency for guest.
3860 Guest ability to manage power state of host cpus (increasing latency
3861 for other processes on the same host cpu, but decreasing latency for
3862 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This
3863 works best when host CPU is not overcommitted. When used, host
3864 estimates of CPU cycle and power utilization will be incorrect, not
3865 taking into account guest idle time.
3866 ERST
3868 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3869 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n"
3870 " the guest without waiting for gdb to connect; use -S too\n"
3871 " if you want it to not start execution.)\n",
3872 QEMU_ARCH_ALL)
3873 SRST
3874 ``-gdb dev``
3875 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter
3876 in the System Emulation Users Guide). Note that this option does not pause QEMU
3877 execution -- if you want QEMU to not start the guest until you
3878 connect with gdb and issue a ``continue`` command, you will need to
3879 also pass the ``-S`` option to QEMU.
3881 The most usual configuration is to listen on a local TCP socket::
3883 -gdb tcp::3117
3885 but you can specify other backends; UDP, pseudo TTY, or even stdio
3886 are all reasonable use cases. For example, a stdio connection
3887 allows you to start QEMU from within gdb and establish the
3888 connection via a pipe:
3890 .. parsed-literal::
3892 (gdb) target remote | exec |qemu_system| -gdb stdio ...
3893 ERST
3895 DEF("s", 0, QEMU_OPTION_s, \
3896 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3897 QEMU_ARCH_ALL)
3898 SRST
3899 ``-s``
3900 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3901 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide).
3902 ERST
3904 DEF("d", HAS_ARG, QEMU_OPTION_d, \
3905 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
3906 QEMU_ARCH_ALL)
3907 SRST
3908 ``-d item1[,...]``
3909 Enable logging of specified items. Use '-d help' for a list of log
3910 items.
3911 ERST
3913 DEF("D", HAS_ARG, QEMU_OPTION_D, \
3914 "-D logfile output log to logfile (default stderr)\n",
3915 QEMU_ARCH_ALL)
3916 SRST
3917 ``-D logfile``
3918 Output log in logfile instead of to stderr
3919 ERST
3921 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3922 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3923 QEMU_ARCH_ALL)
3924 SRST
3925 ``-dfilter range1[,...]``
3926 Filter debug output to that relevant to a range of target addresses.
3927 The filter spec can be either start+size, start-size or start..end
3928 where start end and size are the addresses and sizes required. For
3929 example:
3933 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3935 Will dump output for any code in the 0x1000 sized block starting at
3936 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and
3937 another 0x1000 sized block starting at 0xffffffc00005f000.
3938 ERST
3940 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
3941 "-seed number seed the pseudo-random number generator\n",
3942 QEMU_ARCH_ALL)
3943 SRST
3944 ``-seed number``
3945 Force the guest to use a deterministic pseudo-random number
3946 generator, seeded with number. This does not affect crypto routines
3947 within the host.
3948 ERST
3950 DEF("L", HAS_ARG, QEMU_OPTION_L, \
3951 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
3952 QEMU_ARCH_ALL)
3953 SRST
3954 ``-L path``
3955 Set the directory for the BIOS, VGA BIOS and keymaps.
3957 To list all the data directories, use ``-L help``.
3958 ERST
3960 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3961 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3962 SRST
3963 ``-bios file``
3964 Set the filename for the BIOS.
3965 ERST
3967 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3968 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3969 SRST
3970 ``-enable-kvm``
3971 Enable KVM full virtualization support. This option is only
3972 available if KVM support is enabled when compiling.
3973 ERST
3975 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3976 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL)
3977 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3978 "-xen-attach attach to existing xen domain\n"
3979 " libxl will use this when starting QEMU\n",
3980 QEMU_ARCH_ALL)
3981 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3982 "-xen-domid-restrict restrict set of available xen operations\n"
3983 " to specified domain id. (Does not affect\n"
3984 " xenpv machine type).\n",
3985 QEMU_ARCH_ALL)
3986 SRST
3987 ``-xen-domid id``
3988 Specify xen guest domain id (XEN only).
3990 ``-xen-attach``
3991 Attach to existing xen domain. libxl will use this when starting
3992 QEMU (XEN only). Restrict set of available xen operations to
3993 specified domain id (XEN only).
3994 ERST
3996 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3997 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
3998 SRST
3999 ``-no-reboot``
4000 Exit instead of rebooting.
4001 ERST
4003 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
4004 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
4005 SRST
4006 ``-no-shutdown``
4007 Don't exit QEMU on guest shutdown, but instead only stop the
4008 emulation. This allows for instance switching to monitor to commit
4009 changes to the disk image.
4010 ERST
4012 DEF("action", HAS_ARG, QEMU_OPTION_action,
4013 "-action reboot=reset|shutdown\n"
4014 " action when guest reboots [default=reset]\n"
4015 "-action shutdown=poweroff|pause\n"
4016 " action when guest shuts down [default=poweroff]\n"
4017 "-action panic=pause|shutdown|none\n"
4018 " action when guest panics [default=shutdown]\n"
4019 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
4020 " action when watchdog fires [default=reset]\n",
4021 QEMU_ARCH_ALL)
4022 SRST
4023 ``-action event=action``
4024 The action parameter serves to modify QEMU's default behavior when
4025 certain guest events occur. It provides a generic method for specifying the
4026 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown``
4027 parameters.
4029 Examples:
4031 ``-action panic=none``
4032 ``-action reboot=shutdown,shutdown=pause``
4033 ``-watchdog i6300esb -action watchdog=pause``
4035 ERST
4037 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
4038 "-loadvm [tag|id]\n" \
4039 " start right away with a saved state (loadvm in monitor)\n",
4040 QEMU_ARCH_ALL)
4041 SRST
4042 ``-loadvm file``
4043 Start right away with a saved state (``loadvm`` in monitor)
4044 ERST
4046 #ifndef _WIN32
4047 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
4048 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
4049 #endif
4050 SRST
4051 ``-daemonize``
4052 Daemonize the QEMU process after initialization. QEMU will not
4053 detach from standard IO until it is ready to receive connections on
4054 any of its devices. This option is a useful way for external
4055 programs to launch QEMU without having to cope with initialization
4056 race conditions.
4057 ERST
4059 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
4060 "-option-rom rom load a file, rom, into the option ROM space\n",
4061 QEMU_ARCH_ALL)
4062 SRST
4063 ``-option-rom file``
4064 Load the contents of file as an option ROM. This option is useful to
4065 load things like EtherBoot.
4066 ERST
4068 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
4069 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
4070 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
4071 QEMU_ARCH_ALL)
4073 SRST
4074 ``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]``
4075 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at
4076 the current UTC or local time, respectively. ``localtime`` is
4077 required for correct date in MS-DOS or Windows. To start at a
4078 specific point in time, provide datetime in the format
4079 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC.
4081 By default the RTC is driven by the host system time. This allows
4082 using of the RTC as accurate reference clock inside the guest,
4083 specifically if the host time is smoothly following an accurate
4084 external reference clock, e.g. via NTP. If you want to isolate the
4085 guest time from the host, you can set ``clock`` to ``rt`` instead,
4086 which provides a host monotonic clock if host support it. To even
4087 prevent the RTC from progressing during suspension, you can set
4088 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is
4089 recommended especially in icount mode in order to preserve
4090 determinism; however, note that in icount mode the speed of the
4091 virtual clock is variable and can in general differ from the host
4092 clock.
4094 Enable ``driftfix`` (i386 targets only) if you experience time drift
4095 problems, specifically with Windows' ACPI HAL. This option will try
4096 to figure out how many timer interrupts were not processed by the
4097 Windows guest and will re-inject them.
4098 ERST
4100 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
4101 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \
4102 " enable virtual instruction counter with 2^N clock ticks per\n" \
4103 " instruction, enable aligning the host and virtual clocks\n" \
4104 " or disable real time cpu sleeping, and optionally enable\n" \
4105 " record-and-replay mode\n", QEMU_ARCH_ALL)
4106 SRST
4107 ``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]``
4108 Enable virtual instruction counter. The virtual cpu will execute one
4109 instruction every 2^N ns of virtual time. If ``auto`` is specified
4110 then the virtual cpu speed will be automatically adjusted to keep
4111 virtual time within a few seconds of real time.
4113 Note that while this option can give deterministic behavior, it does
4114 not provide cycle accurate emulation. Modern CPUs contain
4115 superscalar out of order cores with complex cache hierarchies. The
4116 number of instructions executed often has little or no correlation
4117 with actual performance.
4119 When the virtual cpu is sleeping, the virtual time will advance at
4120 default speed unless ``sleep=on`` is specified. With
4121 ``sleep=on``, the virtual time will jump to the next timer
4122 deadline instantly whenever the virtual cpu goes to sleep mode and
4123 will not advance if no timer is enabled. This behavior gives
4124 deterministic execution times from the guest point of view.
4125 The default if icount is enabled is ``sleep=off``.
4126 ``sleep=on`` cannot be used together with either ``shift=auto``
4127 or ``align=on``.
4129 ``align=on`` will activate the delay algorithm which will try to
4130 synchronise the host clock and the virtual clock. The goal is to
4131 have a guest running at the real frequency imposed by the shift
4132 option. Whenever the guest clock is behind the host clock and if
4133 ``align=on`` is specified then we print a message to the user to
4134 inform about the delay. Currently this option does not work when
4135 ``shift`` is ``auto``. Note: The sync algorithm will work for those
4136 shift values for which the guest clock runs ahead of the host clock.
4137 Typically this happens when the shift value is high (how high
4138 depends on the host machine). The default if icount is enabled
4139 is ``align=off``.
4141 When the ``rr`` option is specified deterministic record/replay is
4142 enabled. The ``rrfile=`` option must also be provided to
4143 specify the path to the replay log. In record mode data is written
4144 to this file, and in replay mode it is read back.
4145 If the ``rrsnapshot`` option is given then it specifies a VM snapshot
4146 name. In record mode, a new VM snapshot with the given name is created
4147 at the start of execution recording. In replay mode this option
4148 specifies the snapshot name used to load the initial VM state.
4149 ERST
4151 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
4152 "-watchdog model\n" \
4153 " enable virtual hardware watchdog [default=none]\n",
4154 QEMU_ARCH_ALL)
4155 SRST
4156 ``-watchdog model``
4157 Create a virtual hardware watchdog device. Once enabled (by a guest
4158 action), the watchdog must be periodically polled by an agent inside
4159 the guest or else the guest will be restarted. Choose a model for
4160 which your guest has drivers.
4162 The model is the model of hardware watchdog to emulate. Use
4163 ``-watchdog help`` to list available hardware models. Only one
4164 watchdog can be enabled for a guest.
4166 The following models may be available:
4168 ``ib700``
4169 iBASE 700 is a very simple ISA watchdog with a single timer.
4171 ``i6300esb``
4172 Intel 6300ESB I/O controller hub is a much more featureful
4173 PCI-based dual-timer watchdog.
4175 ``diag288``
4176 A virtual watchdog for s390x backed by the diagnose 288
4177 hypercall (currently KVM only).
4178 ERST
4180 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
4181 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
4182 " action when watchdog fires [default=reset]\n",
4183 QEMU_ARCH_ALL)
4184 SRST
4185 ``-watchdog-action action``
4186 The action controls what QEMU will do when the watchdog timer
4187 expires. The default is ``reset`` (forcefully reset the guest).
4188 Other possible actions are: ``shutdown`` (attempt to gracefully
4189 shutdown the guest), ``poweroff`` (forcefully poweroff the guest),
4190 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the
4191 guest), ``debug`` (print a debug message and continue), or ``none``
4192 (do nothing).
4194 Note that the ``shutdown`` action requires that the guest responds
4195 to ACPI signals, which it may not be able to do in the sort of
4196 situations where the watchdog would have expired, and thus
4197 ``-watchdog-action shutdown`` is not recommended for production use.
4199 Examples:
4201 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700``
4203 ERST
4205 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
4206 "-echr chr set terminal escape character instead of ctrl-a\n",
4207 QEMU_ARCH_ALL)
4208 SRST
4209 ``-echr numeric_ascii_value``
4210 Change the escape character used for switching to the monitor when
4211 using monitor and serial sharing. The default is ``0x01`` when using
4212 the ``-nographic`` option. ``0x01`` is equal to pressing
4213 ``Control-a``. You can select a different character from the ascii
4214 control keys where 1 through 26 map to Control-a through Control-z.
4215 For instance you could use the either of the following to change the
4216 escape character to Control-t.
4218 ``-echr 0x14``; \ ``-echr 20``
4220 ERST
4222 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4223 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
4224 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \
4225 "-incoming unix:socketpath\n" \
4226 " prepare for incoming migration, listen on\n" \
4227 " specified protocol and socket address\n" \
4228 "-incoming fd:fd\n" \
4229 "-incoming exec:cmdline\n" \
4230 " accept incoming migration on given file descriptor\n" \
4231 " or from given external command\n" \
4232 "-incoming defer\n" \
4233 " wait for the URI to be specified via migrate_incoming\n",
4234 QEMU_ARCH_ALL)
4235 SRST
4236 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
4238 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
4239 Prepare for incoming migration, listen on a given tcp port.
4241 ``-incoming unix:socketpath``
4242 Prepare for incoming migration, listen on a given unix socket.
4244 ``-incoming fd:fd``
4245 Accept incoming migration from a given filedescriptor.
4247 ``-incoming exec:cmdline``
4248 Accept incoming migration as an output from specified external
4249 command.
4251 ``-incoming defer``
4252 Wait for the URI to be specified via migrate\_incoming. The monitor
4253 can be used to change settings (such as migration parameters) prior
4254 to issuing the migrate\_incoming to allow the migration to begin.
4255 ERST
4257 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4258 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4259 SRST
4260 ``-only-migratable``
4261 Only allow migratable devices. Devices will not be allowed to enter
4262 an unmigratable state.
4263 ERST
4265 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4266 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4267 SRST
4268 ``-nodefaults``
4269 Don't create default devices. Normally, QEMU sets the default
4270 devices like serial port, parallel port, virtual console, monitor
4271 device, VGA adapter, floppy and CD-ROM drive and others. The
4272 ``-nodefaults`` option will disable all those default devices.
4273 ERST
4275 #ifndef _WIN32
4276 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4277 "-chroot dir chroot to dir just before starting the VM\n",
4278 QEMU_ARCH_ALL)
4279 #endif
4280 SRST
4281 ``-chroot dir``
4282 Immediately before starting guest execution, chroot to the specified
4283 directory. Especially useful in combination with -runas.
4284 ERST
4286 #ifndef _WIN32
4287 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4288 "-runas user change to user id user just before starting the VM\n" \
4289 " user can be numeric uid:gid instead\n",
4290 QEMU_ARCH_ALL)
4291 #endif
4292 SRST
4293 ``-runas user``
4294 Immediately before starting guest execution, drop root privileges,
4295 switching to the specified user.
4296 ERST
4298 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4299 "-prom-env variable=value\n"
4300 " set OpenBIOS nvram variables\n",
4301 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4302 SRST
4303 ``-prom-env variable=value``
4304 Set OpenBIOS nvram variable to given value (PPC, SPARC only).
4308 qemu-system-sparc -prom-env 'auto-boot?=false' \
4309 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
4313 qemu-system-ppc -prom-env 'auto-boot?=false' \
4314 -prom-env 'boot-device=hd:2,\yaboot' \
4315 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
4316 ERST
4317 DEF("semihosting", 0, QEMU_OPTION_semihosting,
4318 "-semihosting semihosting mode\n",
4319 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4320 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4321 SRST
4322 ``-semihosting``
4323 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only).
4325 Note that this allows guest direct access to the host filesystem, so
4326 should only be used with a trusted guest OS.
4328 See the -semihosting-config option documentation for further
4329 information about the facilities this enables.
4330 ERST
4331 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4332 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
4333 " semihosting configuration\n",
4334 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4335 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4336 SRST
4337 ``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]``
4338 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V
4339 only).
4341 Note that this allows guest direct access to the host filesystem, so
4342 should only be used with a trusted guest OS.
4344 On Arm this implements the standard semihosting API, version 2.0.
4346 On M68K this implements the "ColdFire GDB" interface used by
4347 libgloss.
4349 Xtensa semihosting provides basic file IO calls, such as
4350 open/read/write/seek/select. Tensilica baremetal libc for ISS and
4351 linux platform "sim" use this interface.
4353 On RISC-V this implements the standard semihosting API, version 0.2.
4355 ``target=native|gdb|auto``
4356 Defines where the semihosting calls will be addressed, to QEMU
4357 (``native``) or to GDB (``gdb``). The default is ``auto``, which
4358 means ``gdb`` during debug sessions and ``native`` otherwise.
4360 ``chardev=str1``
4361 Send the output to a chardev backend output for native or auto
4362 output when not in gdb
4364 ``arg=str1,arg=str2,...``
4365 Allows the user to pass input arguments, and can be used
4366 multiple times to build up a list. The old-style
4367 ``-kernel``/``-append`` method of passing a command line is
4368 still supported for backward compatibility. If both the
4369 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are
4370 specified, the former is passed to semihosting as it always
4371 takes precedence.
4372 ERST
4373 DEF("old-param", 0, QEMU_OPTION_old_param,
4374 "-old-param old param mode\n", QEMU_ARCH_ARM)
4375 SRST
4376 ``-old-param``
4377 Old param mode (ARM only).
4378 ERST
4380 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4381 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4382 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4383 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4384 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4385 " by the kernel, but typically no longer used by modern\n" \
4386 " C library implementations.\n" \
4387 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \
4388 " to elevate privileges using set*uid|gid system calls.\n" \
4389 " The value 'children' will deny set*uid|gid system calls for\n" \
4390 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4391 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4392 " blocking *fork and execve\n" \
4393 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4394 QEMU_ARCH_ALL)
4395 SRST
4396 ``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]``
4397 Enable Seccomp mode 2 system call filter. 'on' will enable syscall
4398 filtering and 'off' will disable it. The default is 'off'.
4400 ``obsolete=string``
4401 Enable Obsolete system calls
4403 ``elevateprivileges=string``
4404 Disable set\*uid\|gid system calls
4406 ``spawn=string``
4407 Disable \*fork and execve
4409 ``resourcecontrol=string``
4410 Disable process affinity and schedular priority
4411 ERST
4413 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4414 "-readconfig <file>\n", QEMU_ARCH_ALL)
4415 SRST
4416 ``-readconfig file``
4417 Read device configuration from file. This approach is useful when
4418 you want to spawn QEMU process with many command line options but
4419 you don't want to exceed the command line character limit.
4420 ERST
4421 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
4422 "-writeconfig <file>\n"
4423 " read/write config file (deprecated)\n", QEMU_ARCH_ALL)
4424 SRST
4425 ERST
4427 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4428 "-no-user-config\n"
4429 " do not load default user-provided config files at startup\n",
4430 QEMU_ARCH_ALL)
4431 SRST
4432 ``-no-user-config``
4433 The ``-no-user-config`` option makes QEMU not load any of the
4434 user-provided config files on sysconfdir.
4435 ERST
4437 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4438 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4439 " specify tracing options\n",
4440 QEMU_ARCH_ALL)
4441 SRST
4442 ``-trace [[enable=]pattern][,events=file][,file=file]``
4443 .. include:: ../qemu-option-trace.rst.inc
4445 ERST
4446 DEF("plugin", HAS_ARG, QEMU_OPTION_plugin,
4447 "-plugin [file=]<file>[,arg=<string>]\n"
4448 " load a plugin\n",
4449 QEMU_ARCH_ALL)
4450 SRST
4451 ``-plugin file=file[,arg=string]``
4452 Load a plugin.
4454 ``file=file``
4455 Load the given plugin from a shared library file.
4457 ``arg=string``
4458 Argument string passed to the plugin. (Can be given multiple
4459 times.)
4460 ERST
4462 HXCOMM Internal use
4463 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4464 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4466 #ifdef __linux__
4467 DEF("enable-fips", 0, QEMU_OPTION_enablefips,
4468 "-enable-fips enable FIPS 140-2 compliance\n",
4469 QEMU_ARCH_ALL)
4470 #endif
4471 SRST
4472 ``-enable-fips``
4473 Enable FIPS 140-2 compliance mode.
4474 ERST
4476 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4477 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
4478 " control error message format\n"
4479 " timestamp=on enables timestamps (default: off)\n"
4480 " guest-name=on enables guest name prefix but only if\n"
4481 " -name guest option is set (default: off)\n",
4482 QEMU_ARCH_ALL)
4483 SRST
4484 ``-msg [timestamp[=on|off]][,guest-name[=on|off]]``
4485 Control error message format.
4487 ``timestamp=on|off``
4488 Prefix messages with a timestamp. Default is off.
4490 ``guest-name=on|off``
4491 Prefix messages with guest name but only if -name guest option is set
4492 otherwise the option is ignored. Default is off.
4493 ERST
4495 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4496 "-dump-vmstate <file>\n"
4497 " Output vmstate information in JSON format to file.\n"
4498 " Use the scripts/vmstate-static-checker.py file to\n"
4499 " check for possible regressions in migration code\n"
4500 " by comparing two such vmstate dumps.\n",
4501 QEMU_ARCH_ALL)
4502 SRST
4503 ``-dump-vmstate file``
4504 Dump json-encoded vmstate information for current machine type to
4505 file in file
4506 ERST
4508 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4509 "-enable-sync-profile\n"
4510 " enable synchronization profiling\n",
4511 QEMU_ARCH_ALL)
4512 SRST
4513 ``-enable-sync-profile``
4514 Enable synchronization profiling.
4515 ERST
4517 DEFHEADING()
4519 DEFHEADING(Generic object creation:)
4521 DEF("object", HAS_ARG, QEMU_OPTION_object,
4522 "-object TYPENAME[,PROP1=VALUE1,...]\n"
4523 " create a new object of type TYPENAME setting properties\n"
4524 " in the order they are specified. Note that the 'id'\n"
4525 " property must be set. These objects are placed in the\n"
4526 " '/objects' path.\n",
4527 QEMU_ARCH_ALL)
4528 SRST
4529 ``-object typename[,prop1=value1,...]``
4530 Create a new object of type typename setting properties in the order
4531 they are specified. Note that the 'id' property must be set. These
4532 objects are placed in the '/objects' path.
4534 ``-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``
4535 Creates a memory file backend object, which can be used to back
4536 the guest RAM with huge pages.
4538 The ``id`` parameter is a unique ID that will be used to
4539 reference this memory region in other parameters, e.g. ``-numa``,
4540 ``-device nvdimm``, etc.
4542 The ``size`` option provides the size of the memory region, and
4543 accepts common suffixes, e.g. ``500M``.
4545 The ``mem-path`` provides the path to either a shared memory or
4546 huge page filesystem mount.
4548 The ``share`` boolean option determines whether the memory
4549 region is marked as private to QEMU, or shared. The latter
4550 allows a co-operating external process to access the QEMU memory
4551 region.
4553 The ``share`` is also required for pvrdma devices due to
4554 limitations in the RDMA API provided by Linux.
4556 Setting share=on might affect the ability to configure NUMA
4557 bindings for the memory backend under some circumstances, see
4558 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel
4559 source tree for additional details.
4561 Setting the ``discard-data`` boolean option to on indicates that
4562 file contents can be destroyed when QEMU exits, to avoid
4563 unnecessarily flushing data to the backing file. Note that
4564 ``discard-data`` is only an optimization, and QEMU might not
4565 discard file contents if it aborts unexpectedly or is terminated
4566 using SIGKILL.
4568 The ``merge`` boolean option enables memory merge, also known as
4569 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider
4570 the pages for memory deduplication.
4572 Setting the ``dump`` boolean option to off excludes the memory
4573 from core dumps. This feature is also known as MADV\_DONTDUMP.
4575 The ``prealloc`` boolean option enables memory preallocation.
4577 The ``host-nodes`` option binds the memory range to a list of
4578 NUMA host nodes.
4580 The ``policy`` option sets the NUMA policy to one of the
4581 following values:
4583 ``default``
4584 default host policy
4586 ``preferred``
4587 prefer the given host node list for allocation
4589 ``bind``
4590 restrict memory allocation to the given host node list
4592 ``interleave``
4593 interleave memory allocations across the given host node
4594 list
4596 The ``align`` option specifies the base address alignment when
4597 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg
4598 ``2M``. Some backend store specified by ``mem-path`` requires an
4599 alignment different than the default one used by QEMU, eg the
4600 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4601 such cases, users can specify the required alignment via this
4602 option.
4604 The ``pmem`` option specifies whether the backing file specified
4605 by ``mem-path`` is in host persistent memory that can be
4606 accessed using the SNIA NVM programming model (e.g. Intel
4607 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary
4608 operations to guarantee the persistence of its own writes to
4609 ``mem-path`` (e.g. in vNVDIMM label emulation and live
4610 migration). Also, we will map the backend-file with MAP\_SYNC
4611 flag, which ensures the file metadata is in sync for
4612 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC
4613 requires support from both the host kernel (since Linux kernel
4614 4.15) and the filesystem of ``mem-path`` mounted with DAX
4615 option.
4617 The ``readonly`` option specifies whether the backing file is opened
4618 read-only or read-write (default).
4620 ``-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``
4621 Creates a memory backend object, which can be used to back the
4622 guest RAM. Memory backend objects offer more control than the
4623 ``-m`` option that is traditionally used to define guest RAM.
4624 Please refer to ``memory-backend-file`` for a description of the
4625 options.
4627 ``-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``
4628 Creates an anonymous memory file backend object, which allows
4629 QEMU to share the memory with an external process (e.g. when
4630 using vhost-user). The memory is allocated with memfd and
4631 optional sealing. (Linux only)
4633 The ``seal`` option creates a sealed-file, that will block
4634 further resizing the memory ('on' by default).
4636 The ``hugetlb`` option specify the file to be created resides in
4637 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction
4638 with the ``hugetlb`` option, the ``hugetlbsize`` option specify
4639 the hugetlb page size on systems that support multiple hugetlb
4640 page sizes (it must be a power of 2 value supported by the
4641 system).
4643 In some versions of Linux, the ``hugetlb`` option is
4644 incompatible with the ``seal`` option (requires at least Linux
4645 4.16).
4647 Please refer to ``memory-backend-file`` for a description of the
4648 other options.
4650 The ``share`` boolean option is on by default with memfd.
4652 ``-object rng-builtin,id=id``
4653 Creates a random number generator backend which obtains entropy
4654 from QEMU builtin functions. The ``id`` parameter is a unique ID
4655 that will be used to reference this entropy backend from the
4656 ``virtio-rng`` device. By default, the ``virtio-rng`` device
4657 uses this RNG backend.
4659 ``-object rng-random,id=id,filename=/dev/random``
4660 Creates a random number generator backend which obtains entropy
4661 from a device on the host. The ``id`` parameter is a unique ID
4662 that will be used to reference this entropy backend from the
4663 ``virtio-rng`` device. The ``filename`` parameter specifies
4664 which file to obtain entropy from and if omitted defaults to
4665 ``/dev/urandom``.
4667 ``-object rng-egd,id=id,chardev=chardevid``
4668 Creates a random number generator backend which obtains entropy
4669 from an external daemon running on the host. The ``id``
4670 parameter is a unique ID that will be used to reference this
4671 entropy backend from the ``virtio-rng`` device. The ``chardev``
4672 parameter is the unique ID of a character device backend that
4673 provides the connection to the RNG daemon.
4675 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off``
4676 Creates a TLS anonymous credentials object, which can be used to
4677 provide TLS support on network backends. The ``id`` parameter is
4678 a unique ID which network backends will use to access the
4679 credentials. The ``endpoint`` is either ``server`` or ``client``
4680 depending on whether the QEMU network backend that uses the
4681 credentials will be acting as a client or as a server. If
4682 ``verify-peer`` is enabled (the default) then once the handshake
4683 is completed, the peer credentials will be verified, though this
4684 is a no-op for anonymous credentials.
4686 The dir parameter tells QEMU where to find the credential files.
4687 For server endpoints, this directory may contain a file
4688 dh-params.pem providing diffie-hellman parameters to use for the
4689 TLS server. If the file is missing, QEMU will generate a set of
4690 DH parameters at startup. This is a computationally expensive
4691 operation that consumes random pool entropy, so it is
4692 recommended that a persistent set of parameters be generated
4693 upfront and saved.
4695 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]``
4696 Creates a TLS Pre-Shared Keys (PSK) credentials object, which
4697 can be used to provide TLS support on network backends. The
4698 ``id`` parameter is a unique ID which network backends will use
4699 to access the credentials. The ``endpoint`` is either ``server``
4700 or ``client`` depending on whether the QEMU network backend that
4701 uses the credentials will be acting as a client or as a server.
4702 For clients only, ``username`` is the username which will be
4703 sent to the server. If omitted it defaults to "qemu".
4705 The dir parameter tells QEMU where to find the keys file. It is
4706 called "dir/keys.psk" and contains "username:key" pairs. This
4707 file can most easily be created using the GnuTLS ``psktool``
4708 program.
4710 For server endpoints, dir may also contain a file dh-params.pem
4711 providing diffie-hellman parameters to use for the TLS server.
4712 If the file is missing, QEMU will generate a set of DH
4713 parameters at startup. This is a computationally expensive
4714 operation that consumes random pool entropy, so it is
4715 recommended that a persistent set of parameters be generated up
4716 front and saved.
4718 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id``
4719 Creates a TLS anonymous credentials object, which can be used to
4720 provide TLS support on network backends. The ``id`` parameter is
4721 a unique ID which network backends will use to access the
4722 credentials. The ``endpoint`` is either ``server`` or ``client``
4723 depending on whether the QEMU network backend that uses the
4724 credentials will be acting as a client or as a server. If
4725 ``verify-peer`` is enabled (the default) then once the handshake
4726 is completed, the peer credentials will be verified. With x509
4727 certificates, this implies that the clients must be provided
4728 with valid client certificates too.
4730 The dir parameter tells QEMU where to find the credential files.
4731 For server endpoints, this directory may contain a file
4732 dh-params.pem providing diffie-hellman parameters to use for the
4733 TLS server. If the file is missing, QEMU will generate a set of
4734 DH parameters at startup. This is a computationally expensive
4735 operation that consumes random pool entropy, so it is
4736 recommended that a persistent set of parameters be generated
4737 upfront and saved.
4739 For x509 certificate credentials the directory will contain
4740 further files providing the x509 certificates. The certificates
4741 must be stored in PEM format, in filenames ca-cert.pem,
4742 ca-crl.pem (optional), server-cert.pem (only servers),
4743 server-key.pem (only servers), client-cert.pem (only clients),
4744 and client-key.pem (only clients).
4746 For the server-key.pem and client-key.pem files which contain
4747 sensitive private keys, it is possible to use an encrypted
4748 version by providing the passwordid parameter. This provides the
4749 ID of a previously created ``secret`` object containing the
4750 password for decryption.
4752 The priority parameter allows to override the global default
4753 priority used by gnutls. This can be useful if the system
4754 administrator needs to use a weaker set of crypto priorities for
4755 QEMU without potentially forcing the weakness onto all
4756 applications. Or conversely if one wants wants a stronger
4757 default for QEMU than for all other applications, they can do
4758 this through this parameter. Its format is a gnutls priority
4759 string as described at
4760 https://gnutls.org/manual/html_node/Priority-Strings.html.
4762 ``-object tls-cipher-suites,id=id,priority=priority``
4763 Creates a TLS cipher suites object, which can be used to control
4764 the TLS cipher/protocol algorithms that applications are permitted
4765 to use.
4767 The ``id`` parameter is a unique ID which frontends will use to
4768 access the ordered list of permitted TLS cipher suites from the
4769 host.
4771 The ``priority`` parameter allows to override the global default
4772 priority used by gnutls. This can be useful if the system
4773 administrator needs to use a weaker set of crypto priorities for
4774 QEMU without potentially forcing the weakness onto all
4775 applications. Or conversely if one wants wants a stronger
4776 default for QEMU than for all other applications, they can do
4777 this through this parameter. Its format is a gnutls priority
4778 string as described at
4779 https://gnutls.org/manual/html_node/Priority-Strings.html.
4781 An example of use of this object is to control UEFI HTTPS Boot.
4782 The tls-cipher-suites object exposes the ordered list of permitted
4783 TLS cipher suites from the host side to the guest firmware, via
4784 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER
4785 objects. The firmware uses the IANA_TLS_CIPHER array for configuring
4786 guest-side TLS.
4788 In the following example, the priority at which the host-side policy
4789 is retrieved is given by the ``priority`` property.
4790 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to
4791 refer to /etc/crypto-policies/back-ends/gnutls.config.
4793 .. parsed-literal::
4795 # |qemu_system| \\
4796 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\
4797 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
4799 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
4800 Interval t can't be 0, this filter batches the packet delivery:
4801 all packets arriving in a given interval on netdev netdevid are
4802 delayed until the end of the interval. Interval is in
4803 microseconds. ``status`` is optional that indicate whether the
4804 netfilter is on (enabled) or off (disabled), the default status
4805 for netfilter will be 'on'.
4807 queue all\|rx\|tx is an option that can be applied to any
4808 netfilter.
4810 ``all``: the filter is attached both to the receive and the
4811 transmit queue of the netdev (default).
4813 ``rx``: the filter is attached to the receive queue of the
4814 netdev, where it will receive packets sent to the netdev.
4816 ``tx``: the filter is attached to the transmit queue of the
4817 netdev, where it will receive packets sent by the netdev.
4819 position head\|tail\|id=<id> is an option to specify where the
4820 filter should be inserted in the filter list. It can be applied
4821 to any netfilter.
4823 ``head``: the filter is inserted at the head of the filter list,
4824 before any existing filters.
4826 ``tail``: the filter is inserted at the tail of the filter list,
4827 behind any existing filters (default).
4829 ``id=<id>``: the filter is inserted before or behind the filter
4830 specified by <id>, see the insert option below.
4832 insert behind\|before is an option to specify where to insert
4833 the new filter relative to the one specified with
4834 position=id=<id>. It can be applied to any netfilter.
4836 ``before``: insert before the specified filter.
4838 ``behind``: insert behind the specified filter (default).
4840 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
4841 filter-mirror on netdev netdevid,mirror net packet to
4842 chardevchardevid, if it has the vnet\_hdr\_support flag,
4843 filter-mirror will mirror packet with vnet\_hdr\_len.
4845 ``-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]``
4846 filter-redirector on netdev netdevid,redirect filter's net
4847 packet to chardev chardevid,and redirect indev's packet to
4848 filter.if it has the vnet\_hdr\_support flag, filter-redirector
4849 will redirect packet with vnet\_hdr\_len. Create a
4850 filter-redirector we need to differ outdev id from indev id, id
4851 can not be the same. we can just use indev or outdev, but at
4852 least one of indev or outdev need to be specified.
4854 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
4855 Filter-rewriter is a part of COLO project.It will rewrite tcp
4856 packet to secondary from primary to keep secondary tcp
4857 connection,and rewrite tcp packet to primary from secondary make
4858 tcp packet can be handled by client.if it has the
4859 vnet\_hdr\_support flag, we can parse packet with vnet header.
4861 usage: colo secondary: -object
4862 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object
4863 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object
4864 filter-rewriter,id=rew0,netdev=hn0,queue=all
4866 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]``
4867 Dump the network traffic on netdev dev to the file specified by
4868 filename. At most len bytes (64k by default) per packet are
4869 stored. The file format is libpcap, so it can be analyzed with
4870 tools such as tcpdump or Wireshark.
4872 ``-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}]``
4873 Colo-compare gets packet from primary\_in chardevid and
4874 secondary\_in, then compare whether the payload of primary packet
4875 and secondary packet are the same. If same, it will output
4876 primary packet to out\_dev, else it will notify COLO-framework to do
4877 checkpoint and send primary packet to out\_dev. In order to
4878 improve efficiency, we need to put the task of comparison in
4879 another iothread. If it has the vnet\_hdr\_support flag,
4880 colo compare will send/recv packet with vnet\_hdr\_len.
4881 The compare\_timeout=@var{ms} determines the maximum time of the
4882 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms}
4883 is to set the period of scanning expired primary node network packets.
4884 The max\_queue\_size=@var{size} is to set the max compare queue
4885 size depend on user environment.
4886 If user want to use Xen COLO, need to add the notify\_dev to
4887 notify Xen colo-frame to do checkpoint.
4889 COLO-compare must be used with the help of filter-mirror,
4890 filter-redirector and filter-rewriter.
4894 KVM COLO
4896 primary:
4897 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4898 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4899 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
4900 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
4901 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
4902 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4903 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
4904 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4905 -object iothread,id=iothread1
4906 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4907 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4908 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4909 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
4911 secondary:
4912 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4913 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4914 -chardev socket,id=red0,host=3.3.3.3,port=9003
4915 -chardev socket,id=red1,host=3.3.3.3,port=9004
4916 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4917 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4920 Xen COLO
4922 primary:
4923 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4924 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4925 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
4926 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
4927 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
4928 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4929 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
4930 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4931 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off
4932 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4933 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4934 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4935 -object iothread,id=iothread1
4936 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
4938 secondary:
4939 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4940 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4941 -chardev socket,id=red0,host=3.3.3.3,port=9003
4942 -chardev socket,id=red1,host=3.3.3.3,port=9004
4943 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4944 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4946 If you want to know the detail of above command line, you can
4947 read the colo-compare git log.
4949 ``-object cryptodev-backend-builtin,id=id[,queues=queues]``
4950 Creates a cryptodev backend which executes crypto opreation from
4951 the QEMU cipher APIS. The id parameter is a unique ID that will
4952 be used to reference this cryptodev backend from the
4953 ``virtio-crypto`` device. The queues parameter is optional,
4954 which specify the queue number of cryptodev backend, the default
4955 of queues is 1.
4957 .. parsed-literal::
4959 # |qemu_system| \\
4960 [...] \\
4961 -object cryptodev-backend-builtin,id=cryptodev0 \\
4962 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
4963 [...]
4965 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]``
4966 Creates a vhost-user cryptodev backend, backed by a chardev
4967 chardevid. The id parameter is a unique ID that will be used to
4968 reference this cryptodev backend from the ``virtio-crypto``
4969 device. The chardev should be a unix domain socket backed one.
4970 The vhost-user uses a specifically defined protocol to pass
4971 vhost ioctl replacement messages to an application on the other
4972 end of the socket. The queues parameter is optional, which
4973 specify the queue number of cryptodev backend for multiqueue
4974 vhost-user, the default of queues is 1.
4976 .. parsed-literal::
4978 # |qemu_system| \\
4979 [...] \\
4980 -chardev socket,id=chardev0,path=/path/to/socket \\
4981 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\
4982 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
4983 [...]
4985 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]``
4987 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]``
4988 Defines a secret to store a password, encryption key, or some
4989 other sensitive data. The sensitive data can either be passed
4990 directly via the data parameter, or indirectly via the file
4991 parameter. Using the data parameter is insecure unless the
4992 sensitive data is encrypted.
4994 The sensitive data can be provided in raw format (the default),
4995 or base64. When encoded as JSON, the raw format only supports
4996 valid UTF-8 characters, so base64 is recommended for sending
4997 binary data. QEMU will convert from which ever format is
4998 provided to the format it needs internally. eg, an RBD password
4999 can be provided in raw format, even though it will be base64
5000 encoded when passed onto the RBD sever.
5002 For added protection, it is possible to encrypt the data
5003 associated with a secret using the AES-256-CBC cipher. Use of
5004 encryption is indicated by providing the keyid and iv
5005 parameters. The keyid parameter provides the ID of a previously
5006 defined secret that contains the AES-256 decryption key. This
5007 key should be 32-bytes long and be base64 encoded. The iv
5008 parameter provides the random initialization vector used for
5009 encryption of this particular secret and should be a base64
5010 encrypted string of the 16-byte IV.
5012 The simplest (insecure) usage is to provide the secret inline
5014 .. parsed-literal::
5016 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw
5018 The simplest secure usage is to provide the secret via a file
5020 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object
5021 secret,id=sec0,file=mypasswd.txt,format=raw
5023 For greater security, AES-256-CBC should be used. To illustrate
5024 usage, consider the openssl command line tool which can encrypt
5025 the data. Note that when encrypting, the plaintext must be
5026 padded to the cipher block size (32 bytes) using the standard
5027 PKCS#5/6 compatible padding algorithm.
5029 First a master key needs to be created in base64 encoding:
5033 # openssl rand -base64 32 > key.b64
5034 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
5036 Each secret to be encrypted needs to have a random
5037 initialization vector generated. These do not need to be kept
5038 secret
5042 # openssl rand -base64 16 > iv.b64
5043 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
5045 The secret to be defined can now be encrypted, in this case
5046 we're telling openssl to base64 encode the result, but it could
5047 be left as raw bytes if desired.
5051 # SECRET=$(printf "letmein" |
5052 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
5054 When launching QEMU, create a master secret pointing to
5055 ``key.b64`` and specify that to be used to decrypt the user
5056 password. Pass the contents of ``iv.b64`` to the second secret
5058 .. parsed-literal::
5060 # |qemu_system| \\
5061 -object secret,id=secmaster0,format=base64,file=key.b64 \\
5062 -object secret,id=sec0,keyid=secmaster0,format=base64,\\
5063 data=$SECRET,iv=$(<iv.b64)
5065 ``-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]``
5066 Create a Secure Encrypted Virtualization (SEV) guest object,
5067 which can be used to provide the guest memory encryption support
5068 on AMD processors.
5070 When memory encryption is enabled, one of the physical address
5071 bit (aka the C-bit) is utilized to mark if a memory page is
5072 protected. The ``cbitpos`` is used to provide the C-bit
5073 position. The C-bit position is Host family dependent hence user
5074 must provide this value. On EPYC, the value should be 47.
5076 When memory encryption is enabled, we loose certain bits in
5077 physical address space. The ``reduced-phys-bits`` is used to
5078 provide the number of bits we loose in physical address space.
5079 Similar to C-bit, the value is Host family dependent. On EPYC,
5080 the value should be 5.
5082 The ``sev-device`` provides the device file to use for
5083 communicating with the SEV firmware running inside AMD Secure
5084 Processor. The default device is '/dev/sev'. If hardware
5085 supports memory encryption then /dev/sev devices are created by
5086 CCP driver.
5088 The ``policy`` provides the guest policy to be enforced by the
5089 SEV firmware and restrict what configuration and operational
5090 commands can be performed on this guest by the hypervisor. The
5091 policy should be provided by the guest owner and is bound to the
5092 guest and cannot be changed throughout the lifetime of the
5093 guest. The default is 0.
5095 If guest ``policy`` allows sharing the key with another SEV
5096 guest then ``handle`` can be use to provide handle of the guest
5097 from which to share the key.
5099 The ``dh-cert-file`` and ``session-file`` provides the guest
5100 owner's Public Diffie-Hillman key defined in SEV spec. The PDH
5101 and session parameters are used for establishing a cryptographic
5102 session with the guest owner to negotiate keys used for
5103 attestation. The file must be encoded in base64.
5105 e.g to launch a SEV guest
5107 .. parsed-literal::
5109 # |qemu_system_x86| \\
5110 ...... \\
5111 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\
5112 -machine ...,memory-encryption=sev0 \\
5113 .....
5115 ``-object authz-simple,id=id,identity=string``
5116 Create an authorization object that will control access to
5117 network services.
5119 The ``identity`` parameter is identifies the user and its format
5120 depends on the network service that authorization object is
5121 associated with. For authorizing based on TLS x509 certificates,
5122 the identity must be the x509 distinguished name. Note that care
5123 must be taken to escape any commas in the distinguished name.
5125 An example authorization object to validate a x509 distinguished
5126 name would look like:
5128 .. parsed-literal::
5130 # |qemu_system| \\
5131 ... \\
5132 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\
5135 Note the use of quotes due to the x509 distinguished name
5136 containing whitespace, and escaping of ','.
5138 ``-object authz-listfile,id=id,filename=path,refresh=on|off``
5139 Create an authorization object that will control access to
5140 network services.
5142 The ``filename`` parameter is the fully qualified path to a file
5143 containing the access control list rules in JSON format.
5145 An example set of rules that match against SASL usernames might
5146 look like:
5151 "rules": [
5152 { "match": "fred", "policy": "allow", "format": "exact" },
5153 { "match": "bob", "policy": "allow", "format": "exact" },
5154 { "match": "danb", "policy": "deny", "format": "glob" },
5155 { "match": "dan*", "policy": "allow", "format": "exact" },
5157 "policy": "deny"
5160 When checking access the object will iterate over all the rules
5161 and the first rule to match will have its ``policy`` value
5162 returned as the result. If no rules match, then the default
5163 ``policy`` value is returned.
5165 The rules can either be an exact string match, or they can use
5166 the simple UNIX glob pattern matching to allow wildcards to be
5167 used.
5169 If ``refresh`` is set to true the file will be monitored and
5170 automatically reloaded whenever its content changes.
5172 As with the ``authz-simple`` object, the format of the identity
5173 strings being matched depends on the network service, but is
5174 usually a TLS x509 distinguished name, or a SASL username.
5176 An example authorization object to validate a SASL username
5177 would look like:
5179 .. parsed-literal::
5181 # |qemu_system| \\
5182 ... \\
5183 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\
5186 ``-object authz-pam,id=id,service=string``
5187 Create an authorization object that will control access to
5188 network services.
5190 The ``service`` parameter provides the name of a PAM service to
5191 use for authorization. It requires that a file
5192 ``/etc/pam.d/service`` exist to provide the configuration for
5193 the ``account`` subsystem.
5195 An example authorization object to validate a TLS x509
5196 distinguished name would look like:
5198 .. parsed-literal::
5200 # |qemu_system| \\
5201 ... \\
5202 -object authz-pam,id=auth0,service=qemu-vnc \\
5205 There would then be a corresponding config file for PAM at
5206 ``/etc/pam.d/qemu-vnc`` that contains:
5210 account requisite pam_listfile.so item=user sense=allow \
5211 file=/etc/qemu/vnc.allow
5213 Finally the ``/etc/qemu/vnc.allow`` file would contain the list
5214 of x509 distingished names that are permitted access
5218 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
5220 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink``
5221 Creates a dedicated event loop thread that devices can be
5222 assigned to. This is known as an IOThread. By default device
5223 emulation happens in vCPU threads or the main event loop thread.
5224 This can become a scalability bottleneck. IOThreads allow device
5225 emulation and I/O to run on other host CPUs.
5227 The ``id`` parameter is a unique ID that will be used to
5228 reference this IOThread from ``-device ...,iothread=id``.
5229 Multiple devices can be assigned to an IOThread. Note that not
5230 all devices support an ``iothread`` parameter.
5232 The ``query-iothreads`` QMP command lists IOThreads and reports
5233 their thread IDs so that the user can configure host CPU
5234 pinning/affinity.
5236 IOThreads use an adaptive polling algorithm to reduce event loop
5237 latency. Instead of entering a blocking system call to monitor
5238 file descriptors and then pay the cost of being woken up when an
5239 event occurs, the polling algorithm spins waiting for events for
5240 a short time. The algorithm's default parameters are suitable
5241 for many cases but can be adjusted based on knowledge of the
5242 workload and/or host device latency.
5244 The ``poll-max-ns`` parameter is the maximum number of
5245 nanoseconds to busy wait for events. Polling can be disabled by
5246 setting this value to 0.
5248 The ``poll-grow`` parameter is the multiplier used to increase
5249 the polling time when the algorithm detects it is missing events
5250 due to not polling long enough.
5252 The ``poll-shrink`` parameter is the divisor used to decrease
5253 the polling time when the algorithm detects it is spending too
5254 long polling without encountering events.
5256 The polling parameters can be modified at run-time using the
5257 ``qom-set`` command (where ``iothread1`` is the IOThread's
5258 ``id``):
5262 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
5263 ERST
5266 HXCOMM This is the last statement. Insert new options before this line!