Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20210315...
[qemu/ar7.git] / qemu-options.hx
blobfe83ea09b25e03e4d38b424b8082bb3d7c053bf4
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, 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, 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, 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, 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 ``ccid``
1747 Smartcard reader device
1749 ``keyboard``
1750 Standard USB keyboard. Will override the PS/2 keyboard (if present).
1752 ``mouse``
1753 Virtual Mouse. This will override the PS/2 mouse emulation when
1754 activated.
1756 ``tablet``
1757 Pointer device that uses absolute coordinates (like a
1758 touchscreen). This means QEMU is able to report the mouse
1759 position without having to grab the mouse. Also overrides the
1760 PS/2 mouse emulation when activated.
1762 ``wacom-tablet``
1763 Wacom PenPartner USB tablet.
1766 ERST
1768 DEFHEADING()
1770 DEFHEADING(Display options:)
1772 DEF("display", HAS_ARG, QEMU_OPTION_display,
1773 #if defined(CONFIG_SPICE)
1774 "-display spice-app[,gl=on|off]\n"
1775 #endif
1776 #if defined(CONFIG_SDL)
1777 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n"
1778 " [,window_close=on|off][,gl=on|core|es|off]\n"
1779 #endif
1780 #if defined(CONFIG_GTK)
1781 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1782 #endif
1783 #if defined(CONFIG_VNC)
1784 "-display vnc=<display>[,<optargs>]\n"
1785 #endif
1786 #if defined(CONFIG_CURSES)
1787 "-display curses[,charset=<encoding>]\n"
1788 #endif
1789 #if defined(CONFIG_OPENGL)
1790 "-display egl-headless[,rendernode=<file>]\n"
1791 #endif
1792 "-display none\n"
1793 " select display backend type\n"
1794 " The default display is equivalent to\n "
1795 #if defined(CONFIG_GTK)
1796 "\"-display gtk\"\n"
1797 #elif defined(CONFIG_SDL)
1798 "\"-display sdl\"\n"
1799 #elif defined(CONFIG_COCOA)
1800 "\"-display cocoa\"\n"
1801 #elif defined(CONFIG_VNC)
1802 "\"-vnc localhost:0,to=99,id=default\"\n"
1803 #else
1804 "\"-display none\"\n"
1805 #endif
1806 , QEMU_ARCH_ALL)
1807 SRST
1808 ``-display type``
1809 Select type of display to use. This option is a replacement for the
1810 old style -sdl/-curses/... options. Use ``-display help`` to list
1811 the available display types. Valid values for type are
1813 ``sdl``
1814 Display video output via SDL (usually in a separate graphics
1815 window; see the SDL documentation for other possibilities).
1817 ``curses``
1818 Display video output via curses. For graphics device models
1819 which support a text mode, QEMU can display this output using a
1820 curses/ncurses interface. Nothing is displayed when the graphics
1821 device is in graphical mode or if the graphics device does not
1822 support a text mode. Generally only the VGA device models
1823 support text mode. The font charset used by the guest can be
1824 specified with the ``charset`` option, for example
1825 ``charset=CP850`` for IBM CP850 encoding. The default is
1826 ``CP437``.
1828 ``none``
1829 Do not display video output. The guest will still see an
1830 emulated graphics card, but its output will not be displayed to
1831 the QEMU user. This option differs from the -nographic option in
1832 that it only affects what is done with video output; -nographic
1833 also changes the destination of the serial and parallel port
1834 data.
1836 ``gtk``
1837 Display video output in a GTK window. This interface provides
1838 drop-down menus and other UI elements to configure and control
1839 the VM during runtime.
1841 ``vnc``
1842 Start a VNC server on display <arg>
1844 ``egl-headless``
1845 Offload all OpenGL operations to a local DRI device. For any
1846 graphical display, this display needs to be paired with either
1847 VNC or SPICE displays.
1849 ``spice-app``
1850 Start QEMU as a Spice server and launch the default Spice client
1851 application. The Spice server will redirect the serial consoles
1852 and QEMU monitors. (Since 4.0)
1853 ERST
1855 DEF("nographic", 0, QEMU_OPTION_nographic,
1856 "-nographic disable graphical output and redirect serial I/Os to console\n",
1857 QEMU_ARCH_ALL)
1858 SRST
1859 ``-nographic``
1860 Normally, if QEMU is compiled with graphical window support, it
1861 displays output such as guest graphics, guest console, and the QEMU
1862 monitor in a window. With this option, you can totally disable
1863 graphical output so that QEMU is a simple command line application.
1864 The emulated serial port is redirected on the console and muxed with
1865 the monitor (unless redirected elsewhere explicitly). Therefore, you
1866 can still use QEMU to debug a Linux kernel with a serial console.
1867 Use C-a h for help on switching between the console and monitor.
1868 ERST
1870 DEF("curses", 0, QEMU_OPTION_curses,
1871 "-curses shorthand for -display curses\n",
1872 QEMU_ARCH_ALL)
1873 SRST
1874 ``-curses``
1875 Normally, if QEMU is compiled with graphical window support, it
1876 displays output such as guest graphics, guest console, and the QEMU
1877 monitor in a window. With this option, QEMU can display the VGA
1878 output when in text mode using a curses/ncurses interface. Nothing
1879 is displayed in graphical mode.
1880 ERST
1882 DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1883 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1884 QEMU_ARCH_ALL)
1885 SRST
1886 ``-alt-grab``
1887 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that
1888 this also affects the special keys (for fullscreen, monitor-mode
1889 switching, etc).
1890 ERST
1892 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1893 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1894 QEMU_ARCH_ALL)
1895 SRST
1896 ``-ctrl-grab``
1897 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this
1898 also affects the special keys (for fullscreen, monitor-mode
1899 switching, etc).
1900 ERST
1902 DEF("no-quit", 0, QEMU_OPTION_no_quit,
1903 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL)
1904 SRST
1905 ``-no-quit``
1906 Disable SDL window close capability.
1907 ERST
1909 DEF("sdl", 0, QEMU_OPTION_sdl,
1910 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL)
1911 SRST
1912 ``-sdl``
1913 Enable SDL.
1914 ERST
1916 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1917 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1918 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1919 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1920 " [,x509-dh-key-file=<file>][,addr=addr]\n"
1921 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n"
1922 " [,tls-ciphers=<list>]\n"
1923 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1924 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1925 " [,sasl=on|off][,password=<secret>][,disable-ticketing=on|off]\n"
1926 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1927 " [,jpeg-wan-compression=[auto|never|always]]\n"
1928 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
1929 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
1930 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
1931 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1932 " [,gl=[on|off]][,rendernode=<file>]\n"
1933 " enable spice\n"
1934 " at least one of {port, tls-port} is mandatory\n",
1935 QEMU_ARCH_ALL)
1936 SRST
1937 ``-spice option[,option[,...]]``
1938 Enable the spice remote desktop protocol. Valid options are
1940 ``port=<nr>``
1941 Set the TCP port spice is listening on for plaintext channels.
1943 ``addr=<addr>``
1944 Set the IP address spice is listening on. Default is any
1945 address.
1947 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off``
1948 Force using the specified IP version.
1950 ``password=<secret>``
1951 Set the password you need to authenticate.
1953 ``sasl=on|off``
1954 Require that the client use SASL to authenticate with the spice.
1955 The exact choice of authentication method used is controlled
1956 from the system / user's SASL configuration file for the 'qemu'
1957 service. This is typically found in /etc/sasl2/qemu.conf. If
1958 running QEMU as an unprivileged user, an environment variable
1959 SASL\_CONF\_PATH can be used to make it search alternate
1960 locations for the service config. While some SASL auth methods
1961 can also provide data encryption (eg GSSAPI), it is recommended
1962 that SASL always be combined with the 'tls' and 'x509' settings
1963 to enable use of SSL and server certificates. This ensures a
1964 data encryption preventing compromise of authentication
1965 credentials.
1967 ``disable-ticketing=on|off``
1968 Allow client connects without authentication.
1970 ``disable-copy-paste=on|off``
1971 Disable copy paste between the client and the guest.
1973 ``disable-agent-file-xfer=on|off``
1974 Disable spice-vdagent based file-xfer between the client and the
1975 guest.
1977 ``tls-port=<nr>``
1978 Set the TCP port spice is listening on for encrypted channels.
1980 ``x509-dir=<dir>``
1981 Set the x509 file directory. Expects same filenames as -vnc
1982 $display,x509=$dir
1984 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>``
1985 The x509 file names can also be configured individually.
1987 ``tls-ciphers=<list>``
1988 Specify which ciphers to use.
1990 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]``
1991 Force specific channel to be used with or without TLS
1992 encryption. The options can be specified multiple times to
1993 configure multiple channels. The special name "default" can be
1994 used to set the default mode. For channels which are not
1995 explicitly forced into one mode the spice client is allowed to
1996 pick tls/plaintext as he pleases.
1998 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]``
1999 Configure image compression (lossless). Default is auto\_glz.
2001 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]``
2002 Configure wan image compression (lossy for slow links). Default
2003 is auto.
2005 ``streaming-video=[off|all|filter]``
2006 Configure video stream detection. Default is off.
2008 ``agent-mouse=[on|off]``
2009 Enable/disable passing mouse events via vdagent. Default is on.
2011 ``playback-compression=[on|off]``
2012 Enable/disable audio stream compression (using celt 0.5.1).
2013 Default is on.
2015 ``seamless-migration=[on|off]``
2016 Enable/disable spice seamless migration. Default is off.
2018 ``gl=[on|off]``
2019 Enable/disable OpenGL context. Default is off.
2021 ``rendernode=<file>``
2022 DRM render node for OpenGL rendering. If not specified, it will
2023 pick the first available. (Since 2.9)
2024 ERST
2026 DEF("portrait", 0, QEMU_OPTION_portrait,
2027 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
2028 QEMU_ARCH_ALL)
2029 SRST
2030 ``-portrait``
2031 Rotate graphical output 90 deg left (only PXA LCD).
2032 ERST
2034 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
2035 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
2036 QEMU_ARCH_ALL)
2037 SRST
2038 ``-rotate deg``
2039 Rotate graphical output some deg left (only PXA LCD).
2040 ERST
2042 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
2043 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
2044 " select video card type\n", QEMU_ARCH_ALL)
2045 SRST
2046 ``-vga type``
2047 Select type of VGA card to emulate. Valid values for type are
2049 ``cirrus``
2050 Cirrus Logic GD5446 Video card. All Windows versions starting
2051 from Windows 95 should recognize and use this graphic card. For
2052 optimal performances, use 16 bit color depth in the guest and
2053 the host OS. (This card was the default before QEMU 2.2)
2055 ``std``
2056 Standard VGA card with Bochs VBE extensions. If your guest OS
2057 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if
2058 you want to use high resolution modes (>= 1280x1024x16) then you
2059 should use this option. (This card is the default since QEMU
2060 2.2)
2062 ``vmware``
2063 VMWare SVGA-II compatible adapter. Use it if you have
2064 sufficiently recent XFree86/XOrg server or Windows guest with a
2065 driver for this card.
2067 ``qxl``
2068 QXL paravirtual graphic card. It is VGA compatible (including
2069 VESA 2.0 VBE support). Works best with qxl guest drivers
2070 installed though. Recommended choice when using the spice
2071 protocol.
2073 ``tcx``
2074 (sun4m only) Sun TCX framebuffer. This is the default
2075 framebuffer for sun4m machines and offers both 8-bit and 24-bit
2076 colour depths at a fixed resolution of 1024x768.
2078 ``cg3``
2079 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit
2080 framebuffer for sun4m machines available in both 1024x768
2081 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people
2082 wishing to run older Solaris versions.
2084 ``virtio``
2085 Virtio VGA card.
2087 ``none``
2088 Disable VGA card.
2089 ERST
2091 DEF("full-screen", 0, QEMU_OPTION_full_screen,
2092 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
2093 SRST
2094 ``-full-screen``
2095 Start in full screen.
2096 ERST
2098 DEF("g", HAS_ARG, QEMU_OPTION_g ,
2099 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
2100 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
2101 SRST
2102 ``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]``
2103 Set the initial graphical resolution and depth (PPC, SPARC only).
2105 For PPC the default is 800x600x32.
2107 For SPARC with the TCX graphics device, the default is 1024x768x8
2108 with the option of 1024x768x24. For cgthree, the default is
2109 1024x768x8 with the option of 1152x900x8 for people who wish to use
2110 OBP.
2111 ERST
2113 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
2114 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
2115 SRST
2116 ``-vnc display[,option[,option[,...]]]``
2117 Normally, if QEMU is compiled with graphical window support, it
2118 displays output such as guest graphics, guest console, and the QEMU
2119 monitor in a window. With this option, you can have QEMU listen on
2120 VNC display display and redirect the VGA display over the VNC
2121 session. It is very useful to enable the usb tablet device when
2122 using this option (option ``-device usb-tablet``). When using the
2123 VNC display, you must use the ``-k`` parameter to set the keyboard
2124 layout if you are not using en-us. Valid syntax for the display is
2126 ``to=L``
2127 With this option, QEMU will try next available VNC displays,
2128 until the number L, if the origianlly defined "-vnc display" is
2129 not available, e.g. port 5900+display is already used by another
2130 application. By default, to=0.
2132 ``host:d``
2133 TCP connections will only be allowed from host on display d. By
2134 convention the TCP port is 5900+d. Optionally, host can be
2135 omitted in which case the server will accept connections from
2136 any host.
2138 ``unix:path``
2139 Connections will be allowed over UNIX domain sockets where path
2140 is the location of a unix socket to listen for connections on.
2142 ``none``
2143 VNC is initialized but not started. The monitor ``change``
2144 command can be used to later start the VNC server.
2146 Following the display value there may be one or more option flags
2147 separated by commas. Valid options are
2149 ``reverse=on|off``
2150 Connect to a listening VNC client via a "reverse" connection.
2151 The client is specified by the display. For reverse network
2152 connections (host:d,``reverse``), the d argument is a TCP port
2153 number, not a display number.
2155 ``websocket=on|off``
2156 Opens an additional TCP listening port dedicated to VNC
2157 Websocket connections. If a bare websocket option is given, the
2158 Websocket port is 5700+display. An alternative port can be
2159 specified with the syntax ``websocket``\ =port.
2161 If host is specified connections will only be allowed from this
2162 host. It is possible to control the websocket listen address
2163 independently, using the syntax ``websocket``\ =host:port.
2165 If no TLS credentials are provided, the websocket connection
2166 runs in unencrypted mode. If TLS credentials are provided, the
2167 websocket connection requires encrypted client connections.
2169 ``password=on|off``
2170 Require that password based authentication is used for client
2171 connections.
2173 The password must be set separately using the ``set_password``
2174 command in the :ref:`QEMU monitor`. The
2175 syntax to change your password is:
2176 ``set_password <protocol> <password>`` where <protocol> could be
2177 either "vnc" or "spice".
2179 If you would like to change <protocol> password expiration, you
2180 should use ``expire_password <protocol> <expiration-time>``
2181 where expiration time could be one of the following options:
2182 now, never, +seconds or UNIX time of expiration, e.g. +60 to
2183 make password expire in 60 seconds, or 1335196800 to make
2184 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for
2185 this date and time).
2187 You can also use keywords "now" or "never" for the expiration
2188 time to allow <protocol> password to expire immediately or never
2189 expire.
2191 ``tls-creds=ID``
2192 Provides the ID of a set of TLS credentials to use to secure the
2193 VNC server. They will apply to both the normal VNC server socket
2194 and the websocket socket (if enabled). Setting TLS credentials
2195 will cause the VNC server socket to enable the VeNCrypt auth
2196 mechanism. The credentials should have been previously created
2197 using the ``-object tls-creds`` argument.
2199 ``tls-authz=ID``
2200 Provides the ID of the QAuthZ authorization object against which
2201 the client's x509 distinguished name will validated. This object
2202 is only resolved at time of use, so can be deleted and recreated
2203 on the fly while the VNC server is active. If missing, it will
2204 default to denying access.
2206 ``sasl=on|off``
2207 Require that the client use SASL to authenticate with the VNC
2208 server. The exact choice of authentication method used is
2209 controlled from the system / user's SASL configuration file for
2210 the 'qemu' service. This is typically found in
2211 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user,
2212 an environment variable SASL\_CONF\_PATH can be used to make it
2213 search alternate locations for the service config. While some
2214 SASL auth methods can also provide data encryption (eg GSSAPI),
2215 it is recommended that SASL always be combined with the 'tls'
2216 and 'x509' settings to enable use of SSL and server
2217 certificates. This ensures a data encryption preventing
2218 compromise of authentication credentials. See the
2219 :ref:`VNC security` section in the System Emulation Users Guide
2220 for details on using SASL authentication.
2222 ``sasl-authz=ID``
2223 Provides the ID of the QAuthZ authorization object against which
2224 the client's SASL username will validated. This object is only
2225 resolved at time of use, so can be deleted and recreated on the
2226 fly while the VNC server is active. If missing, it will default
2227 to denying access.
2229 ``acl=on|off``
2230 Legacy method for enabling authorization of clients against the
2231 x509 distinguished name and SASL username. It results in the
2232 creation of two ``authz-list`` objects with IDs of
2233 ``vnc.username`` and ``vnc.x509dname``. The rules for these
2234 objects must be configured with the HMP ACL commands.
2236 This option is deprecated and should no longer be used. The new
2237 ``sasl-authz`` and ``tls-authz`` options are a replacement.
2239 ``lossy=on|off``
2240 Enable lossy compression methods (gradient, JPEG, ...). If this
2241 option is set, VNC client may receive lossy framebuffer updates
2242 depending on its encoding settings. Enabling this option can
2243 save a lot of bandwidth at the expense of quality.
2245 ``non-adaptive=on|off``
2246 Disable adaptive encodings. Adaptive encodings are enabled by
2247 default. An adaptive encoding will try to detect frequently
2248 updated screen regions, and send updates in these regions using
2249 a lossy encoding (like JPEG). This can be really helpful to save
2250 bandwidth when playing videos. Disabling adaptive encodings
2251 restores the original static behavior of encodings like Tight.
2253 ``share=[allow-exclusive|force-shared|ignore]``
2254 Set display sharing policy. 'allow-exclusive' allows clients to
2255 ask for exclusive access. As suggested by the rfb spec this is
2256 implemented by dropping other connections. Connecting multiple
2257 clients in parallel requires all clients asking for a shared
2258 session (vncviewer: -shared switch). This is the default.
2259 'force-shared' disables exclusive client access. Useful for
2260 shared desktop sessions, where you don't want someone forgetting
2261 specify -shared disconnect everybody else. 'ignore' completely
2262 ignores the shared flag and allows everybody connect
2263 unconditionally. Doesn't conform to the rfb spec but is
2264 traditional QEMU behavior.
2266 ``key-delay-ms``
2267 Set keyboard delay, for key down and key up events, in
2268 milliseconds. Default is 10. Keyboards are low-bandwidth
2269 devices, so this slowdown can help the device and guest to keep
2270 up and not lose events in case events are arriving in bulk.
2271 Possible causes for the latter are flaky network connections, or
2272 scripts for automated testing.
2274 ``audiodev=audiodev``
2275 Use the specified audiodev when the VNC client requests audio
2276 transmission. When not using an -audiodev argument, this option
2277 must be omitted, otherwise is must be present and specify a
2278 valid audiodev.
2280 ``power-control=on|off``
2281 Permit the remote client to issue shutdown, reboot or reset power
2282 control requests.
2283 ERST
2285 ARCHHEADING(, QEMU_ARCH_I386)
2287 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2289 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2290 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2291 QEMU_ARCH_I386)
2292 SRST
2293 ``-win2k-hack``
2294 Use it when installing Windows 2000 to avoid a disk full bug. After
2295 Windows 2000 is installed, you no longer need this option (this
2296 option slows down the IDE transfers).
2297 ERST
2299 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2300 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2301 QEMU_ARCH_I386)
2302 SRST
2303 ``-no-fd-bootchk``
2304 Disable boot signature checking for floppy disks in BIOS. May be
2305 needed to boot from old floppy disks.
2306 ERST
2308 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2309 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2310 SRST
2311 ``-no-acpi``
2312 Disable ACPI (Advanced Configuration and Power Interface) support.
2313 Use it if your guest OS complains about ACPI problems (PC target
2314 machine only).
2315 ERST
2317 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2318 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2319 SRST
2320 ``-no-hpet``
2321 Disable HPET support.
2322 ERST
2324 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2325 "-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"
2326 " ACPI table description\n", QEMU_ARCH_I386)
2327 SRST
2328 ``-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]...]``
2329 Add ACPI table with specified header fields and context from
2330 specified files. For file=, take whole ACPI table from the specified
2331 files, including all ACPI headers (possible overridden by other
2332 options). For data=, only data portion of the table is used, all
2333 header information is specified in the command line. If a SLIC table
2334 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id
2335 fields will override the same in the RSDT and the FADT (a.k.a.
2336 FACP), in order to ensure the field matches required by the
2337 Microsoft SLIC spec and the ACPI spec.
2338 ERST
2340 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2341 "-smbios file=binary\n"
2342 " load SMBIOS entry from binary file\n"
2343 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2344 " [,uefi=on|off]\n"
2345 " specify SMBIOS type 0 fields\n"
2346 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2347 " [,uuid=uuid][,sku=str][,family=str]\n"
2348 " specify SMBIOS type 1 fields\n"
2349 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2350 " [,asset=str][,location=str]\n"
2351 " specify SMBIOS type 2 fields\n"
2352 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2353 " [,sku=str]\n"
2354 " specify SMBIOS type 3 fields\n"
2355 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2356 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
2357 " specify SMBIOS type 4 fields\n"
2358 "-smbios type=11[,value=str][,path=filename]\n"
2359 " specify SMBIOS type 11 fields\n"
2360 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2361 " [,asset=str][,part=str][,speed=%d]\n"
2362 " specify SMBIOS type 17 fields\n",
2363 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2364 SRST
2365 ``-smbios file=binary``
2366 Load SMBIOS entry from binary file.
2368 ``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]``
2369 Specify SMBIOS type 0 fields
2371 ``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]``
2372 Specify SMBIOS type 1 fields
2374 ``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]``
2375 Specify SMBIOS type 2 fields
2377 ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
2378 Specify SMBIOS type 3 fields
2380 ``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]``
2381 Specify SMBIOS type 4 fields
2383 ``-smbios type=11[,value=str][,path=filename]``
2384 Specify SMBIOS type 11 fields
2386 This argument can be repeated multiple times, and values are added in the order they are parsed.
2387 Applications intending to use OEM strings data are encouraged to use their application name as
2388 a prefix for the value string. This facilitates passing information for multiple applications
2389 concurrently.
2391 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax
2392 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes.
2394 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to
2395 the SMBIOS table in the order in which they appear.
2397 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535
2398 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the
2399 guest. Instead it should be used as a indicator to inform the guest where to locate the real
2400 data set, for example, by specifying the serial ID of a block device.
2402 An example passing three strings is
2404 .. parsed-literal::
2406 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\
2407 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\
2408 path=/some/file/with/oemstringsdata.txt
2410 In the guest OS this is visible with the ``dmidecode`` command
2412 .. parsed-literal::
2414 $ dmidecode -t 11
2415 Handle 0x0E00, DMI type 11, 5 bytes
2416 OEM Strings
2417 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/
2418 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os
2419 String 3: myapp:some extra data
2422 ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
2423 Specify SMBIOS type 17 fields
2424 ERST
2426 DEFHEADING()
2428 DEFHEADING(Network options:)
2430 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2431 #ifdef CONFIG_SLIRP
2432 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n"
2433 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2434 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2435 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2436 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2437 #ifndef _WIN32
2438 "[,smb=dir[,smbserver=addr]]\n"
2439 #endif
2440 " configure a user mode network backend with ID 'str',\n"
2441 " its DHCP server and optional services\n"
2442 #endif
2443 #ifdef _WIN32
2444 "-netdev tap,id=str,ifname=name\n"
2445 " configure a host TAP network backend with ID 'str'\n"
2446 #else
2447 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2448 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2449 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2450 " [,poll-us=n]\n"
2451 " configure a host TAP network backend with ID 'str'\n"
2452 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2453 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2454 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2455 " to deconfigure it\n"
2456 " use '[down]script=no' to disable script execution\n"
2457 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2458 " configure it\n"
2459 " use 'fd=h' to connect to an already opened TAP interface\n"
2460 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2461 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2462 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2463 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2464 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2465 " use vhost=on to enable experimental in kernel accelerator\n"
2466 " (only has effect for virtio guests which use MSIX)\n"
2467 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2468 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2469 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2470 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2471 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n"
2472 " spent on busy polling for vhost net\n"
2473 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2474 " configure a host TAP network backend with ID 'str' that is\n"
2475 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2476 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2477 #endif
2478 #ifdef __linux__
2479 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2480 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n"
2481 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n"
2482 " [,rxcookie=rxcookie][,offset=offset]\n"
2483 " configure a network backend with ID 'str' connected to\n"
2484 " an Ethernet over L2TPv3 pseudowire.\n"
2485 " Linux kernel 3.3+ as well as most routers can talk\n"
2486 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2487 " VM to a router and even VM to Host. It is a nearly-universal\n"
2488 " standard (RFC3931). Note - this implementation uses static\n"
2489 " pre-configured tunnels (same as the Linux kernel).\n"
2490 " use 'src=' to specify source address\n"
2491 " use 'dst=' to specify destination address\n"
2492 " use 'udp=on' to specify udp encapsulation\n"
2493 " use 'srcport=' to specify source udp port\n"
2494 " use 'dstport=' to specify destination udp port\n"
2495 " use 'ipv6=on' to force v6\n"
2496 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2497 " well as a weak security measure\n"
2498 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2499 " use 'txcookie=0x012345678' to specify a txcookie\n"
2500 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2501 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2502 " use 'pincounter=on' to work around broken counter handling in peer\n"
2503 " use 'offset=X' to add an extra offset between header and data\n"
2504 #endif
2505 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2506 " configure a network backend to connect to another network\n"
2507 " using a socket connection\n"
2508 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2509 " configure a network backend to connect to a multicast maddr and port\n"
2510 " use 'localaddr=addr' to specify the host address to send packets from\n"
2511 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2512 " configure a network backend to connect to another network\n"
2513 " using an UDP tunnel\n"
2514 #ifdef CONFIG_VDE
2515 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2516 " configure a network backend to connect to port 'n' of a vde switch\n"
2517 " running on host and listening for incoming connections on 'socketpath'.\n"
2518 " Use group 'groupname' and mode 'octalmode' to change default\n"
2519 " ownership and permissions for communication port.\n"
2520 #endif
2521 #ifdef CONFIG_NETMAP
2522 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2523 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2524 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2525 " netmap device, defaults to '/dev/netmap')\n"
2526 #endif
2527 #ifdef CONFIG_POSIX
2528 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2529 " configure a vhost-user network, backed by a chardev 'dev'\n"
2530 #endif
2531 #ifdef __linux__
2532 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n"
2533 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n"
2534 #endif
2535 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2536 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2537 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2538 "-nic [tap|bridge|"
2539 #ifdef CONFIG_SLIRP
2540 "user|"
2541 #endif
2542 #ifdef __linux__
2543 "l2tpv3|"
2544 #endif
2545 #ifdef CONFIG_VDE
2546 "vde|"
2547 #endif
2548 #ifdef CONFIG_NETMAP
2549 "netmap|"
2550 #endif
2551 #ifdef CONFIG_POSIX
2552 "vhost-user|"
2553 #endif
2554 "socket][,option][,...][mac=macaddr]\n"
2555 " initialize an on-board / default host NIC (using MAC address\n"
2556 " macaddr) and connect it to the given host network backend\n"
2557 "-nic none use it alone to have zero network devices (the default is to\n"
2558 " provided a 'user' network connection)\n",
2559 QEMU_ARCH_ALL)
2560 DEF("net", HAS_ARG, QEMU_OPTION_net,
2561 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2562 " configure or create an on-board (or machine default) NIC and\n"
2563 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2564 "-net ["
2565 #ifdef CONFIG_SLIRP
2566 "user|"
2567 #endif
2568 "tap|"
2569 "bridge|"
2570 #ifdef CONFIG_VDE
2571 "vde|"
2572 #endif
2573 #ifdef CONFIG_NETMAP
2574 "netmap|"
2575 #endif
2576 "socket][,option][,option][,...]\n"
2577 " old way to initialize a host network interface\n"
2578 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2579 SRST
2580 ``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
2581 This option is a shortcut for configuring both the on-board
2582 (default) guest NIC hardware and the host network backend in one go.
2583 The host backend options are the same as with the corresponding
2584 ``-netdev`` options below. The guest NIC model can be set with
2585 ``model=modelname``. Use ``model=help`` to list the available device
2586 types. The hardware MAC address can be set with ``mac=macaddr``.
2588 The following two example do exactly the same, to show how ``-nic``
2589 can be used to shorten the command line length:
2591 .. parsed-literal::
2593 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2594 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2596 ``-nic none``
2597 Indicate that no network devices should be configured. It is used to
2598 override the default configuration (default NIC with "user" host
2599 network backend) which is activated if no other networking options
2600 are provided.
2602 ``-netdev user,id=id[,option][,option][,...]``
2603 Configure user mode host network backend which requires no
2604 administrator privilege to run. Valid options are:
2606 ``id=id``
2607 Assign symbolic name for use in monitor commands.
2609 ``ipv4=on|off and ipv6=on|off``
2610 Specify that either IPv4 or IPv6 must be enabled. If neither is
2611 specified both protocols are enabled.
2613 ``net=addr[/mask]``
2614 Set IP network address the guest will see. Optionally specify
2615 the netmask, either in the form a.b.c.d or as number of valid
2616 top-most bits. Default is 10.0.2.0/24.
2618 ``host=addr``
2619 Specify the guest-visible address of the host. Default is the
2620 2nd IP in the guest network, i.e. x.x.x.2.
2622 ``ipv6-net=addr[/int]``
2623 Set IPv6 network address the guest will see (default is
2624 fec0::/64). The network prefix is given in the usual hexadecimal
2625 IPv6 address notation. The prefix size is optional, and is given
2626 as the number of valid top-most bits (default is 64).
2628 ``ipv6-host=addr``
2629 Specify the guest-visible IPv6 address of the host. Default is
2630 the 2nd IPv6 in the guest network, i.e. xxxx::2.
2632 ``restrict=on|off``
2633 If this option is enabled, the guest will be isolated, i.e. it
2634 will not be able to contact the host and no guest IP packets
2635 will be routed over the host to the outside. This option does
2636 not affect any explicitly set forwarding rules.
2638 ``hostname=name``
2639 Specifies the client hostname reported by the built-in DHCP
2640 server.
2642 ``dhcpstart=addr``
2643 Specify the first of the 16 IPs the built-in DHCP server can
2644 assign. Default is the 15th to 31st IP in the guest network,
2645 i.e. x.x.x.15 to x.x.x.31.
2647 ``dns=addr``
2648 Specify the guest-visible address of the virtual nameserver. The
2649 address must be different from the host address. Default is the
2650 3rd IP in the guest network, i.e. x.x.x.3.
2652 ``ipv6-dns=addr``
2653 Specify the guest-visible address of the IPv6 virtual
2654 nameserver. The address must be different from the host address.
2655 Default is the 3rd IP in the guest network, i.e. xxxx::3.
2657 ``dnssearch=domain``
2658 Provides an entry for the domain-search list sent by the
2659 built-in DHCP server. More than one domain suffix can be
2660 transmitted by specifying this option multiple times. If
2661 supported, this will cause the guest to automatically try to
2662 append the given domain suffix(es) in case a domain name can not
2663 be resolved.
2665 Example:
2667 .. parsed-literal::
2669 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2671 ``domainname=domain``
2672 Specifies the client domain name reported by the built-in DHCP
2673 server.
2675 ``tftp=dir``
2676 When using the user mode network stack, activate a built-in TFTP
2677 server. The files in dir will be exposed as the root of a TFTP
2678 server. The TFTP client on the guest must be configured in
2679 binary mode (use the command ``bin`` of the Unix TFTP client).
2681 ``tftp-server-name=name``
2682 In BOOTP reply, broadcast name as the "TFTP server name"
2683 (RFC2132 option 66). This can be used to advise the guest to
2684 load boot files or configurations from a different server than
2685 the host address.
2687 ``bootfile=file``
2688 When using the user mode network stack, broadcast file as the
2689 BOOTP filename. In conjunction with ``tftp``, this can be used
2690 to network boot a guest from a local directory.
2692 Example (using pxelinux):
2694 .. parsed-literal::
2696 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\
2697 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2699 ``smb=dir[,smbserver=addr]``
2700 When using the user mode network stack, activate a built-in SMB
2701 server so that Windows OSes can access to the host files in
2702 ``dir`` transparently. The IP address of the SMB server can be
2703 set to addr. By default the 4th IP in the guest network is used,
2704 i.e. x.x.x.4.
2706 In the guest Windows OS, the line:
2710 10.0.2.4 smbserver
2712 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
2713 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
2714 NT/2000).
2716 Then ``dir`` can be accessed in ``\\smbserver\qemu``.
2718 Note that a SAMBA server must be installed on the host OS.
2720 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport``
2721 Redirect incoming TCP or UDP connections to the host port
2722 hostport to the guest IP address guestaddr on guest port
2723 guestport. If guestaddr is not specified, its value is x.x.x.15
2724 (default first address given by the built-in DHCP server). By
2725 specifying hostaddr, the rule can be bound to a specific host
2726 interface. If no connection type is set, TCP is used. This
2727 option can be given multiple times.
2729 For example, to redirect host X11 connection from screen 1 to
2730 guest screen 0, use the following:
2732 .. parsed-literal::
2734 # on the host
2735 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2736 # this host xterm should open in the guest X11 server
2737 xterm -display :1
2739 To redirect telnet connections from host port 5555 to telnet
2740 port on the guest, use the following:
2742 .. parsed-literal::
2744 # on the host
2745 |qemu_system| -nic user,hostfwd=tcp::5555-:23
2746 telnet localhost 5555
2748 Then when you use on the host ``telnet localhost 5555``, you
2749 connect to the guest telnet server.
2751 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command``
2752 Forward guest TCP connections to the IP address server on port
2753 port to the character device dev or to a program executed by
2754 cmd:command which gets spawned for each connection. This option
2755 can be given multiple times.
2757 You can either use a chardev directly and have that one used
2758 throughout QEMU's lifetime, like in the following example:
2760 .. parsed-literal::
2762 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2763 # the guest accesses it
2764 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2766 Or you can execute a command on every TCP connection established
2767 by the guest, so that QEMU behaves similar to an inetd process
2768 for that virtual server:
2770 .. parsed-literal::
2772 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2773 # and connect the TCP stream to its stdin/stdout
2774 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2776 ``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]``
2777 Configure a host TAP network backend with ID id.
2779 Use the network script file to configure it and the network script
2780 dfile to deconfigure it. If name is not provided, the OS
2781 automatically provides one. The default network configure script is
2782 ``/etc/qemu-ifup`` and the default network deconfigure script is
2783 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to
2784 disable script execution.
2786 If running QEMU as an unprivileged user, use the network helper
2787 to configure the TAP interface and attach it to the bridge.
2788 The default network helper executable is
2789 ``/path/to/qemu-bridge-helper`` and the default bridge device is
2790 ``br0``.
2792 ``fd``\ =h can be used to specify the handle of an already opened
2793 host TAP interface.
2795 Examples:
2797 .. parsed-literal::
2799 #launch a QEMU instance with the default network script
2800 |qemu_system| linux.img -nic tap
2802 .. parsed-literal::
2804 #launch a QEMU instance with two NICs, each one connected
2805 #to a TAP device
2806 |qemu_system| linux.img \\
2807 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\
2808 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2810 .. parsed-literal::
2812 #launch a QEMU instance with the default network helper to
2813 #connect a TAP device to bridge br0
2814 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
2815 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2817 ``-netdev bridge,id=id[,br=bridge][,helper=helper]``
2818 Connect a host TAP network interface to a host bridge device.
2820 Use the network helper helper to configure the TAP interface and
2821 attach it to the bridge. The default network helper executable is
2822 ``/path/to/qemu-bridge-helper`` and the default bridge device is
2823 ``br0``.
2825 Examples:
2827 .. parsed-literal::
2829 #launch a QEMU instance with the default network helper to
2830 #connect a TAP device to bridge br0
2831 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2833 .. parsed-literal::
2835 #launch a QEMU instance with the default network helper to
2836 #connect a TAP device to bridge qemubr0
2837 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2839 ``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]``
2840 This host network backend can be used to connect the guest's network
2841 to another QEMU virtual machine using a TCP socket connection. If
2842 ``listen`` is specified, QEMU waits for incoming connections on port
2843 (host is optional). ``connect`` is used to connect to another QEMU
2844 instance using the ``listen`` option. ``fd``\ =h specifies an
2845 already opened TCP socket.
2847 Example:
2849 .. parsed-literal::
2851 # launch a first QEMU instance
2852 |qemu_system| linux.img \\
2853 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2854 -netdev socket,id=n1,listen=:1234
2855 # connect the network of this instance to the network of the first instance
2856 |qemu_system| linux.img \\
2857 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
2858 -netdev socket,id=n2,connect=127.0.0.1:1234
2860 ``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]``
2861 Configure a socket host network backend to share the guest's network
2862 traffic with another QEMU virtual machines using a UDP multicast
2863 socket, effectively making a bus for every QEMU with same multicast
2864 address maddr and port. NOTES:
2866 1. Several QEMU can be running on different hosts and share same bus
2867 (assuming correct multicast setup for these hosts).
2869 2. mcast support is compatible with User Mode Linux (argument
2870 ``ethN=mcast``), see http://user-mode-linux.sf.net.
2872 3. Use ``fd=h`` to specify an already opened UDP multicast socket.
2874 Example:
2876 .. parsed-literal::
2878 # launch one QEMU instance
2879 |qemu_system| linux.img \\
2880 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2881 -netdev socket,id=n1,mcast=230.0.0.1:1234
2882 # launch another QEMU instance on same "bus"
2883 |qemu_system| linux.img \\
2884 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
2885 -netdev socket,id=n2,mcast=230.0.0.1:1234
2886 # launch yet another QEMU instance on same "bus"
2887 |qemu_system| linux.img \\
2888 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\
2889 -netdev socket,id=n3,mcast=230.0.0.1:1234
2891 Example (User Mode Linux compat.):
2893 .. parsed-literal::
2895 # launch QEMU instance (note mcast address selected is UML's default)
2896 |qemu_system| linux.img \\
2897 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2898 -netdev socket,id=n1,mcast=239.192.168.1:1102
2899 # launch UML
2900 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2902 Example (send packets from host's 1.2.3.4):
2904 .. parsed-literal::
2906 |qemu_system| linux.img \\
2907 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
2908 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2910 ``-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]``
2911 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
2912 is a popular protocol to transport Ethernet (and other Layer 2) data
2913 frames between two systems. It is present in routers, firewalls and
2914 the Linux kernel (from version 3.3 onwards).
2916 This transport allows a VM to communicate to another VM, router or
2917 firewall directly.
2919 ``src=srcaddr``
2920 source address (mandatory)
2922 ``dst=dstaddr``
2923 destination address (mandatory)
2925 ``udp``
2926 select udp encapsulation (default is ip).
2928 ``srcport=srcport``
2929 source udp port.
2931 ``dstport=dstport``
2932 destination udp port.
2934 ``ipv6``
2935 force v6, otherwise defaults to v4.
2937 ``rxcookie=rxcookie``; \ ``txcookie=txcookie``
2938 Cookies are a weak form of security in the l2tpv3 specification.
2939 Their function is mostly to prevent misconfiguration. By default
2940 they are 32 bit.
2942 ``cookie64``
2943 Set cookie size to 64 bit instead of the default 32
2945 ``counter=off``
2946 Force a 'cut-down' L2TPv3 with no counter as in
2947 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2949 ``pincounter=on``
2950 Work around broken counter handling in peer. This may also help
2951 on networks which have packet reorder.
2953 ``offset=offset``
2954 Add an extra offset between header and data
2956 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to
2957 the bridge br-lan on the remote Linux host 1.2.3.4:
2959 .. parsed-literal::
2961 # Setup tunnel on linux host using raw ip as encapsulation
2962 # on 1.2.3.4
2963 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\
2964 encap udp udp_sport 16384 udp_dport 16384
2965 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\
2966 0xFFFFFFFF peer_session_id 0xFFFFFFFF
2967 ifconfig vmtunnel0 mtu 1500
2968 ifconfig vmtunnel0 up
2969 brctl addif br-lan vmtunnel0
2972 # on 4.3.2.1
2973 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2975 |qemu_system| linux.img -device e1000,netdev=n1 \\
2976 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2978 ``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]``
2979 Configure VDE backend to connect to PORT n of a vde switch running
2980 on host and listening for incoming connections on socketpath. Use
2981 GROUP groupname and MODE octalmode to change default ownership and
2982 permissions for communication port. This option is only available if
2983 QEMU has been compiled with vde support enabled.
2985 Example:
2987 .. parsed-literal::
2989 # launch vde switch
2990 vde_switch -F -sock /tmp/myswitch
2991 # launch QEMU instance
2992 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch
2994 ``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
2995 Establish a vhost-user netdev, backed by a chardev id. The chardev
2996 should be a unix domain socket backed one. The vhost-user uses a
2997 specifically defined protocol to pass vhost ioctl replacement
2998 messages to an application on the other end of the socket. On
2999 non-MSIX guests, the feature can be forced with vhostforce. Use
3000 'queues=n' to specify the number of queues to be created for
3001 multiqueue vhost-user.
3003 Example:
3007 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
3008 -numa node,memdev=mem \
3009 -chardev socket,id=chr0,path=/path/to/socket \
3010 -netdev type=vhost-user,id=net0,chardev=chr0 \
3011 -device virtio-net-pci,netdev=net0
3013 ``-netdev vhost-vdpa,vhostdev=/path/to/dev``
3014 Establish a vhost-vdpa netdev.
3016 vDPA device is a device that uses a datapath which complies with
3017 the virtio specifications with a vendor specific control path.
3018 vDPA devices can be both physically located on the hardware or
3019 emulated by software.
3021 ``-netdev hubport,id=id,hubid=hubid[,netdev=nd]``
3022 Create a hub port on the emulated hub with ID hubid.
3024 The hubport netdev lets you connect a NIC to a QEMU emulated hub
3025 instead of a single netdev. Alternatively, you can also connect the
3026 hubport to another netdev with ID nd by using the ``netdev=nd``
3027 option.
3029 ``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]``
3030 Legacy option to configure or create an on-board (or machine
3031 default) Network Interface Card(NIC) and connect it either to the
3032 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd.
3033 If model is omitted, then the default NIC model associated with the
3034 machine type is used. Note that the default NIC model may change in
3035 future QEMU releases, so it is highly recommended to always specify
3036 a model. Optionally, the MAC address can be changed to mac, the
3037 device address set to addr (PCI cards only), and a name can be
3038 assigned for use in monitor commands. Optionally, for PCI cards, you
3039 can specify the number v of MSI-X vectors that the card should have;
3040 this option currently only affects virtio cards; set v = 0 to
3041 disable MSI-X. If no ``-net`` option is specified, a single NIC is
3042 created. QEMU can emulate several different models of network card.
3043 Use ``-net nic,model=help`` for a list of available devices for your
3044 target.
3046 ``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]``
3047 Configure a host network backend (with the options corresponding to
3048 the same ``-netdev`` option) and connect it to the emulated hub 0
3049 (the default hub). Use name to specify the name of the hub port.
3050 ERST
3052 DEFHEADING()
3054 DEFHEADING(Character device options:)
3056 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
3057 "-chardev help\n"
3058 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3059 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n"
3060 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
3061 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
3062 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
3063 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n"
3064 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
3065 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
3066 " [,logfile=PATH][,logappend=on|off]\n"
3067 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3068 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
3069 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3070 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
3071 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3072 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3073 #ifdef _WIN32
3074 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3075 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3076 #else
3077 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3078 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
3079 #endif
3080 #ifdef CONFIG_BRLAPI
3081 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3082 #endif
3083 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
3084 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
3085 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3086 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3087 #endif
3088 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
3089 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3090 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3091 #endif
3092 #if defined(CONFIG_SPICE)
3093 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3094 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3095 #endif
3096 , QEMU_ARCH_ALL
3099 SRST
3100 The general form of a character device option is:
3102 ``-chardev backend,id=id[,mux=on|off][,options]``
3103 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``,
3104 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``,
3105 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``,
3106 ``spicevmc``, ``spiceport``. The specific backend will determine the
3107 applicable options.
3109 Use ``-chardev help`` to print all available chardev backend types.
3111 All devices must have an id, which can be any string up to 127
3112 characters long. It is used to uniquely identify this device in
3113 other command line directives.
3115 A character device may be used in multiplexing mode by multiple
3116 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is
3117 a "1:N" device, and here the "1" end is your specified chardev
3118 backend, and the "N" end is the various parts of QEMU that can talk
3119 to a chardev. If you create a chardev with ``id=myid`` and
3120 ``mux=on``, QEMU will create a multiplexer with your specified ID,
3121 and you can then configure multiple front ends to use that chardev
3122 ID for their input/output. Up to four different front ends can be
3123 connected to a single multiplexed chardev. (Without multiplexing
3124 enabled, a chardev can only be used by a single front end.) For
3125 instance you could use this to allow a single stdio chardev to be
3126 used by two serial ports and the QEMU monitor:
3130 -chardev stdio,mux=on,id=char0 \
3131 -mon chardev=char0,mode=readline \
3132 -serial chardev:char0 \
3133 -serial chardev:char0
3135 You can have more than one multiplexer in a system configuration;
3136 for instance you could have a TCP port multiplexed between UART 0
3137 and UART 1, and stdio multiplexed between the QEMU monitor and a
3138 parallel port:
3142 -chardev stdio,mux=on,id=char0 \
3143 -mon chardev=char0,mode=readline \
3144 -parallel chardev:char0 \
3145 -chardev tcp,...,mux=on,id=char1 \
3146 -serial chardev:char1 \
3147 -serial chardev:char1
3149 When you're using a multiplexed character device, some escape
3150 sequences are interpreted in the input. See the chapter about
3151 :ref:`keys in the character backend multiplexer` in the
3152 System Emulation Users Guide for more details.
3154 Note that some other command line options may implicitly create
3155 multiplexed character backends; for instance ``-serial mon:stdio``
3156 creates a multiplexed stdio backend connected to the serial port and
3157 the QEMU monitor, and ``-nographic`` also multiplexes the console
3158 and the monitor to stdio.
3160 There is currently no support for multiplexing in the other
3161 direction (where a single QEMU front end takes input and output from
3162 multiple chardevs).
3164 Every backend supports the ``logfile`` option, which supplies the
3165 path to a file to record all data transmitted via the backend. The
3166 ``logappend`` option controls whether the log file will be truncated
3167 or appended to when opened.
3169 The available backends are:
3171 ``-chardev null,id=id``
3172 A void device. This device will not emit any data, and will drop any
3173 data it receives. The null backend does not take any options.
3175 ``-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]``
3176 Create a two-way stream socket, which can be either a TCP or a unix
3177 socket. A unix socket will be created if ``path`` is specified.
3178 Behaviour is undefined if TCP options are specified for a unix
3179 socket.
3181 ``server=on|off`` specifies that the socket shall be a listening socket.
3183 ``wait=on|off`` specifies that QEMU should not block waiting for a client
3184 to connect to a listening socket.
3186 ``telnet=on|off`` specifies that traffic on the socket should interpret
3187 telnet escape sequences.
3189 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for
3190 communication.
3192 ``reconnect`` sets the timeout for reconnecting on non-server
3193 sockets when the remote end goes away. qemu will delay this many
3194 seconds and then attempt to reconnect. Zero disables reconnecting,
3195 and is the default.
3197 ``tls-creds`` requests enablement of the TLS protocol for
3198 encryption, and specifies the id of the TLS credentials to use for
3199 the handshake. The credentials must be previously created with the
3200 ``-object tls-creds`` argument.
3202 ``tls-auth`` provides the ID of the QAuthZ authorization object
3203 against which the client's x509 distinguished name will be
3204 validated. This object is only resolved at time of use, so can be
3205 deleted and recreated on the fly while the chardev server is active.
3206 If missing, it will default to denying access.
3208 TCP and unix socket options are given below:
3210 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]``
3211 ``host`` for a listening socket specifies the local address to
3212 be bound. For a connecting socket species the remote host to
3213 connect to. ``host`` is optional for listening sockets. If not
3214 specified it defaults to ``0.0.0.0``.
3216 ``port`` for a listening socket specifies the local port to be
3217 bound. For a connecting socket specifies the port on the remote
3218 host to connect to. ``port`` can be given as either a port
3219 number or a service name. ``port`` is required.
3221 ``to`` is only relevant to listening sockets. If it is
3222 specified, and ``port`` cannot be bound, QEMU will attempt to
3223 bind to subsequent ports up to and including ``to`` until it
3224 succeeds. ``to`` must be specified as a port number.
3226 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4
3227 or IPv6 must be used. If neither is specified the socket may
3228 use either protocol.
3230 ``nodelay=on|off`` disables the Nagle algorithm.
3232 ``unix options: path=path[,abstract=on|off][,tight=on|off]``
3233 ``path`` specifies the local path of the unix socket. ``path``
3234 is required.
3235 ``abstract=on|off`` specifies the use of the abstract socket namespace,
3236 rather than the filesystem. Optional, defaults to false.
3237 ``tight=on|off`` sets the socket length of abstract sockets to their minimum,
3238 rather than the full sun_path length. Optional, defaults to true.
3240 ``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]``
3241 Sends all traffic from the guest to a remote host over UDP.
3243 ``host`` specifies the remote host to connect to. If not specified
3244 it defaults to ``localhost``.
3246 ``port`` specifies the port on the remote host to connect to.
3247 ``port`` is required.
3249 ``localaddr`` specifies the local address to bind to. If not
3250 specified it defaults to ``0.0.0.0``.
3252 ``localport`` specifies the local port to bind to. If not specified
3253 any available local port will be used.
3255 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used.
3256 If neither is specified the device may use either protocol.
3258 ``-chardev msmouse,id=id``
3259 Forward QEMU's emulated msmouse events to the guest. ``msmouse``
3260 does not take any options.
3262 ``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]``
3263 Connect to a QEMU text console. ``vc`` may optionally be given a
3264 specific size.
3266 ``width`` and ``height`` specify the width and height respectively
3267 of the console, in pixels.
3269 ``cols`` and ``rows`` specify that the console be sized to fit a
3270 text console with the given dimensions.
3272 ``-chardev ringbuf,id=id[,size=size]``
3273 Create a ring buffer with fixed size ``size``. size must be a power
3274 of two and defaults to ``64K``.
3276 ``-chardev file,id=id,path=path``
3277 Log all traffic received from the guest to a file.
3279 ``path`` specifies the path of the file to be opened. This file will
3280 be created if it does not already exist, and overwritten if it does.
3281 ``path`` is required.
3283 ``-chardev pipe,id=id,path=path``
3284 Create a two-way connection to the guest. The behaviour differs
3285 slightly between Windows hosts and other hosts:
3287 On Windows, a single duplex pipe will be created at
3288 ``\\.pipe\path``.
3290 On other hosts, 2 pipes will be created called ``path.in`` and
3291 ``path.out``. Data written to ``path.in`` will be received by the
3292 guest. Data written by the guest can be read from ``path.out``. QEMU
3293 will not create these fifos, and requires them to be present.
3295 ``path`` forms part of the pipe path as described above. ``path`` is
3296 required.
3298 ``-chardev console,id=id``
3299 Send traffic from the guest to QEMU's standard output. ``console``
3300 does not take any options.
3302 ``console`` is only available on Windows hosts.
3304 ``-chardev serial,id=id,path=path``
3305 Send traffic from the guest to a serial device on the host.
3307 On Unix hosts serial will actually accept any tty device, not only
3308 serial lines.
3310 ``path`` specifies the name of the serial device to open.
3312 ``-chardev pty,id=id``
3313 Create a new pseudo-terminal on the host and connect to it. ``pty``
3314 does not take any options.
3316 ``pty`` is not available on Windows hosts.
3318 ``-chardev stdio,id=id[,signal=on|off]``
3319 Connect to standard input and standard output of the QEMU process.
3321 ``signal`` controls if signals are enabled on the terminal, that
3322 includes exiting QEMU with the key sequence Control-c. This option
3323 is enabled by default, use ``signal=off`` to disable it.
3325 ``-chardev braille,id=id``
3326 Connect to a local BrlAPI server. ``braille`` does not take any
3327 options.
3329 ``-chardev tty,id=id,path=path``
3330 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD
3331 and DragonFlyBSD hosts. It is an alias for ``serial``.
3333 ``path`` specifies the path to the tty. ``path`` is required.
3335 ``-chardev parallel,id=id,path=path``
3337 ``-chardev parport,id=id,path=path``
3338 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD
3339 hosts.
3341 Connect to a local parallel port.
3343 ``path`` specifies the path to the parallel port device. ``path`` is
3344 required.
3346 ``-chardev spicevmc,id=id,debug=debug,name=name``
3347 ``spicevmc`` is only available when spice support is built in.
3349 ``debug`` debug level for spicevmc
3351 ``name`` name of spice channel to connect to
3353 Connect to a spice virtual machine channel, such as vdiport.
3355 ``-chardev spiceport,id=id,debug=debug,name=name``
3356 ``spiceport`` is only available when spice support is built in.
3358 ``debug`` debug level for spicevmc
3360 ``name`` name of spice port to connect to
3362 Connect to a spice port, allowing a Spice client to handle the
3363 traffic identified by a name (preferably a fqdn).
3364 ERST
3366 DEFHEADING()
3368 #ifdef CONFIG_TPM
3369 DEFHEADING(TPM device options:)
3371 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3372 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3373 " use path to provide path to a character device; default is /dev/tpm0\n"
3374 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3375 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3376 "-tpmdev emulator,id=id,chardev=dev\n"
3377 " configure the TPM device using chardev backend\n",
3378 QEMU_ARCH_ALL)
3379 SRST
3380 The general form of a TPM device option is:
3382 ``-tpmdev backend,id=id[,options]``
3383 The specific backend type will determine the applicable options. The
3384 ``-tpmdev`` option creates the TPM backend and requires a
3385 ``-device`` option that specifies the TPM frontend interface model.
3387 Use ``-tpmdev help`` to print all available TPM backend types.
3389 The available backends are:
3391 ``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path``
3392 (Linux-host only) Enable access to the host's TPM using the
3393 passthrough driver.
3395 ``path`` specifies the path to the host's TPM device, i.e., on a
3396 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by
3397 default ``/dev/tpm0`` is used.
3399 ``cancel-path`` specifies the path to the host TPM device's sysfs
3400 entry allowing for cancellation of an ongoing TPM command.
3401 ``cancel-path`` is optional and by default QEMU will search for the
3402 sysfs entry to use.
3404 Some notes about using the host's TPM with the passthrough driver:
3406 The TPM device accessed by the passthrough driver must not be used
3407 by any other application on the host.
3409 Since the host's firmware (BIOS/UEFI) has already initialized the
3410 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize
3411 the TPM again and may therefore not show a TPM-specific menu that
3412 would otherwise allow the user to configure the TPM, e.g., allow the
3413 user to enable/disable or activate/deactivate the TPM. Further, if
3414 TPM ownership is released from within a VM then the host's TPM will
3415 get disabled and deactivated. To enable and activate the TPM again
3416 afterwards, the host has to be rebooted and the user is required to
3417 enter the firmware's menu to enable and activate the TPM. If the TPM
3418 is left disabled and/or deactivated most TPM commands will fail.
3420 To create a passthrough TPM use the following two options:
3424 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3426 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by
3427 ``tpmdev=tpm0`` in the device option.
3429 ``-tpmdev emulator,id=id,chardev=dev``
3430 (Linux-host only) Enable access to a TPM emulator using Unix domain
3431 socket based chardev backend.
3433 ``chardev`` specifies the unique ID of a character device backend
3434 that provides connection to the software TPM server.
3436 To create a TPM emulator backend device with chardev socket backend:
3440 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3441 ERST
3443 DEFHEADING()
3445 #endif
3447 DEFHEADING(Linux/Multiboot boot specific:)
3448 SRST
3449 When using these options, you can use a given Linux or Multiboot kernel
3450 without installing it in the disk image. It can be useful for easier
3451 testing of various kernels.
3454 ERST
3456 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3457 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3458 SRST
3459 ``-kernel bzImage``
3460 Use bzImage as kernel image. The kernel can be either a Linux kernel
3461 or in multiboot format.
3462 ERST
3464 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3465 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3466 SRST
3467 ``-append cmdline``
3468 Use cmdline as kernel command line
3469 ERST
3471 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3472 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3473 SRST
3474 ``-initrd file``
3475 Use file as initial ram disk.
3477 ``-initrd "file1 arg=foo,file2"``
3478 This syntax is only available with multiboot.
3480 Use file1 and file2 as modules and pass arg=foo as parameter to the
3481 first module.
3482 ERST
3484 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3485 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3486 SRST
3487 ``-dtb file``
3488 Use file as a device tree binary (dtb) image and pass it to the
3489 kernel on boot.
3490 ERST
3492 DEFHEADING()
3494 DEFHEADING(Debug/Expert options:)
3496 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3497 "-fw_cfg [name=]<name>,file=<file>\n"
3498 " add named fw_cfg entry with contents from file\n"
3499 "-fw_cfg [name=]<name>,string=<str>\n"
3500 " add named fw_cfg entry with contents from string\n",
3501 QEMU_ARCH_ALL)
3502 SRST
3503 ``-fw_cfg [name=]name,file=file``
3504 Add named fw\_cfg entry with contents from file file.
3506 ``-fw_cfg [name=]name,string=str``
3507 Add named fw\_cfg entry with contents from string str.
3509 The terminating NUL character of the contents of str will not be
3510 included as part of the fw\_cfg item data. To insert contents with
3511 embedded NUL characters, you have to use the file parameter.
3513 The fw\_cfg entries are passed by QEMU through to the guest.
3515 Example:
3519 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3521 creates an fw\_cfg entry named opt/com.mycompany/blob with contents
3522 from ./my\_blob.bin.
3523 ERST
3525 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3526 "-serial dev redirect the serial port to char device 'dev'\n",
3527 QEMU_ARCH_ALL)
3528 SRST
3529 ``-serial dev``
3530 Redirect the virtual serial port to host character device dev. The
3531 default device is ``vc`` in graphical mode and ``stdio`` in non
3532 graphical mode.
3534 This option can be used several times to simulate up to 4 serial
3535 ports.
3537 Use ``-serial none`` to disable all serial ports.
3539 Available character devices are:
3541 ``vc[:WxH]``
3542 Virtual console. Optionally, a width and height can be given in
3543 pixel with
3547 vc:800x600
3549 It is also possible to specify width or height in characters:
3553 vc:80Cx24C
3555 ``pty``
3556 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3558 ``none``
3559 No device is allocated.
3561 ``null``
3562 void device
3564 ``chardev:id``
3565 Use a named character device defined with the ``-chardev``
3566 option.
3568 ``/dev/XXX``
3569 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial
3570 port parameters are set according to the emulated ones.
3572 ``/dev/parportN``
3573 [Linux only, parallel port only] Use host parallel port N.
3574 Currently SPP and EPP parallel port features can be used.
3576 ``file:filename``
3577 Write output to filename. No character can be read.
3579 ``stdio``
3580 [Unix only] standard input/output
3582 ``pipe:filename``
3583 name pipe filename
3585 ``COMn``
3586 [Windows only] Use host serial port n
3588 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]``
3589 This implements UDP Net Console. When remote\_host or src\_ip
3590 are not specified they default to ``0.0.0.0``. When not using a
3591 specified src\_port a random port is automatically chosen.
3593 If you just want a simple readonly console you can use
3594 ``netcat`` or ``nc``, by starting QEMU with:
3595 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time
3596 QEMU writes something to that port it will appear in the
3597 netconsole session.
3599 If you plan to send characters back via netconsole or you want
3600 to stop and start QEMU a lot of times, you should have QEMU use
3601 the same source port each time by using something like ``-serial
3602 udp::4555@:4556`` to QEMU. Another approach is to use a patched
3603 version of netcat which can listen to a TCP port and send and
3604 receive characters via udp. If you have a patched version of
3605 netcat which activates telnet remote echo and single char
3606 transfer, then you can use the following options to set up a
3607 netcat redirector to allow telnet on port 5555 to access the
3608 QEMU port.
3610 ``QEMU Options:``
3611 -serial udp::4555@:4556
3613 ``netcat options:``
3614 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3616 ``telnet options:``
3617 localhost 5555
3619 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]``
3620 The TCP Net Console has two modes of operation. It can send the
3621 serial I/O to a location or wait for a connection from a
3622 location. By default the TCP Net Console is sent to host at the
3623 port. If you use the ``server=on`` option QEMU will wait for a client
3624 socket application to connect to the port before continuing,
3625 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off``
3626 option disables the Nagle buffering algorithm. The ``reconnect=on``
3627 option only applies if ``server=no`` is set, if the connection goes
3628 down it will attempt to reconnect at the given interval. If host
3629 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a
3630 time is accepted. You can use ``telnet=on`` to connect to the
3631 corresponding character device.
3633 ``Example to send tcp console to 192.168.0.2 port 4444``
3634 -serial tcp:192.168.0.2:4444
3636 ``Example to listen and wait on port 4444 for connection``
3637 -serial tcp::4444,server=on
3639 ``Example to not wait and listen on ip 192.168.0.100 port 4444``
3640 -serial tcp:192.168.0.100:4444,server=on,wait=off
3642 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]``
3643 The telnet protocol is used instead of raw tcp sockets. The
3644 options work the same as if you had specified ``-serial tcp``.
3645 The difference is that the port acts like a telnet server or
3646 client using telnet option negotiation. This will also allow you
3647 to send the MAGIC\_SYSRQ sequence if you use a telnet that
3648 supports sending the break sequence. Typically in unix telnet
3649 you do it with Control-] and then type "send break" followed by
3650 pressing the enter key.
3652 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]``
3653 The WebSocket protocol is used instead of raw tcp socket. The
3654 port acts as a WebSocket server. Client mode is not supported.
3656 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]``
3657 A unix domain socket is used instead of a tcp socket. The option
3658 works the same as if you had specified ``-serial tcp`` except
3659 the unix domain socket path is used for connections.
3661 ``mon:dev_string``
3662 This is a special option to allow the monitor to be multiplexed
3663 onto another serial port. The monitor is accessed with key
3664 sequence of Control-a and then pressing c. dev\_string should be
3665 any one of the serial devices specified above. An example to
3666 multiplex the monitor onto a telnet server listening on port
3667 4444 would be:
3669 ``-serial mon:telnet::4444,server=on,wait=off``
3671 When the monitor is multiplexed to stdio in this way, Ctrl+C
3672 will not terminate QEMU any more but will be passed to the guest
3673 instead.
3675 ``braille``
3676 Braille device. This will use BrlAPI to display the braille
3677 output on a real or fake device.
3679 ``msmouse``
3680 Three button serial mouse. Configure the guest to use Microsoft
3681 protocol.
3682 ERST
3684 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3685 "-parallel dev redirect the parallel port to char device 'dev'\n",
3686 QEMU_ARCH_ALL)
3687 SRST
3688 ``-parallel dev``
3689 Redirect the virtual parallel port to host device dev (same devices
3690 as the serial port). On Linux hosts, ``/dev/parportN`` can be used
3691 to use hardware devices connected on the corresponding host parallel
3692 port.
3694 This option can be used several times to simulate up to 3 parallel
3695 ports.
3697 Use ``-parallel none`` to disable all parallel ports.
3698 ERST
3700 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3701 "-monitor dev redirect the monitor to char device 'dev'\n",
3702 QEMU_ARCH_ALL)
3703 SRST
3704 ``-monitor dev``
3705 Redirect the monitor to host device dev (same devices as the serial
3706 port). The default device is ``vc`` in graphical mode and ``stdio``
3707 in non graphical mode. Use ``-monitor none`` to disable the default
3708 monitor.
3709 ERST
3710 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3711 "-qmp dev like -monitor but opens in 'control' mode\n",
3712 QEMU_ARCH_ALL)
3713 SRST
3714 ``-qmp dev``
3715 Like -monitor but opens in 'control' mode.
3716 ERST
3717 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3718 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3719 QEMU_ARCH_ALL)
3720 SRST
3721 ``-qmp-pretty dev``
3722 Like -qmp but uses pretty JSON formatting.
3723 ERST
3725 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3726 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3727 SRST
3728 ``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
3729 Setup monitor on chardev name. ``pretty`` turns on JSON pretty
3730 printing easing human reading and debugging.
3731 ERST
3733 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3734 "-debugcon dev redirect the debug console to char device 'dev'\n",
3735 QEMU_ARCH_ALL)
3736 SRST
3737 ``-debugcon dev``
3738 Redirect the debug console to host device dev (same devices as the
3739 serial port). The debug console is an I/O port which is typically
3740 port 0xe9; writing to that I/O port sends output to this device. The
3741 default device is ``vc`` in graphical mode and ``stdio`` in non
3742 graphical mode.
3743 ERST
3745 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3746 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
3747 SRST
3748 ``-pidfile file``
3749 Store the QEMU process PID in file. It is useful if you launch QEMU
3750 from a script.
3751 ERST
3753 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3754 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL)
3755 SRST
3756 ``-singlestep``
3757 Run the emulation in single step mode.
3758 ERST
3760 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3761 "--preconfig pause QEMU before machine is initialized (experimental)\n",
3762 QEMU_ARCH_ALL)
3763 SRST
3764 ``--preconfig``
3765 Pause QEMU for interactive configuration before the machine is
3766 created, which allows querying and configuring properties that will
3767 affect machine initialization. Use QMP command 'x-exit-preconfig' to
3768 exit the preconfig state and move to the next state (i.e. run guest
3769 if -S isn't used or pause the second time if -S is used). This
3770 option is experimental.
3771 ERST
3773 DEF("S", 0, QEMU_OPTION_S, \
3774 "-S freeze CPU at startup (use 'c' to start execution)\n",
3775 QEMU_ARCH_ALL)
3776 SRST
3777 ``-S``
3778 Do not start CPU at startup (you must type 'c' in the monitor).
3779 ERST
3781 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3782 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3783 " run qemu with overcommit hints\n"
3784 " mem-lock=on|off controls memory lock support (default: off)\n"
3785 " cpu-pm=on|off controls cpu power management (default: off)\n",
3786 QEMU_ARCH_ALL)
3787 SRST
3788 ``-overcommit mem-lock=on|off``
3790 ``-overcommit cpu-pm=on|off``
3791 Run qemu with hints about host resource overcommit. The default is
3792 to assume that host overcommits all resources.
3794 Locking qemu and guest memory can be enabled via ``mem-lock=on``
3795 (disabled by default). This works when host memory is not
3796 overcommitted and reduces the worst-case latency for guest.
3798 Guest ability to manage power state of host cpus (increasing latency
3799 for other processes on the same host cpu, but decreasing latency for
3800 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This
3801 works best when host CPU is not overcommitted. When used, host
3802 estimates of CPU cycle and power utilization will be incorrect, not
3803 taking into account guest idle time.
3804 ERST
3806 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3807 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n"
3808 " the guest without waiting for gdb to connect; use -S too\n"
3809 " if you want it to not start execution.)\n",
3810 QEMU_ARCH_ALL)
3811 SRST
3812 ``-gdb dev``
3813 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter
3814 in the System Emulation Users Guide). Note that this option does not pause QEMU
3815 execution -- if you want QEMU to not start the guest until you
3816 connect with gdb and issue a ``continue`` command, you will need to
3817 also pass the ``-S`` option to QEMU.
3819 The most usual configuration is to listen on a local TCP socket::
3821 -gdb tcp::3117
3823 but you can specify other backends; UDP, pseudo TTY, or even stdio
3824 are all reasonable use cases. For example, a stdio connection
3825 allows you to start QEMU from within gdb and establish the
3826 connection via a pipe:
3828 .. parsed-literal::
3830 (gdb) target remote | exec |qemu_system| -gdb stdio ...
3831 ERST
3833 DEF("s", 0, QEMU_OPTION_s, \
3834 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3835 QEMU_ARCH_ALL)
3836 SRST
3837 ``-s``
3838 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3839 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide).
3840 ERST
3842 DEF("d", HAS_ARG, QEMU_OPTION_d, \
3843 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
3844 QEMU_ARCH_ALL)
3845 SRST
3846 ``-d item1[,...]``
3847 Enable logging of specified items. Use '-d help' for a list of log
3848 items.
3849 ERST
3851 DEF("D", HAS_ARG, QEMU_OPTION_D, \
3852 "-D logfile output log to logfile (default stderr)\n",
3853 QEMU_ARCH_ALL)
3854 SRST
3855 ``-D logfile``
3856 Output log in logfile instead of to stderr
3857 ERST
3859 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3860 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3861 QEMU_ARCH_ALL)
3862 SRST
3863 ``-dfilter range1[,...]``
3864 Filter debug output to that relevant to a range of target addresses.
3865 The filter spec can be either start+size, start-size or start..end
3866 where start end and size are the addresses and sizes required. For
3867 example:
3871 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3873 Will dump output for any code in the 0x1000 sized block starting at
3874 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and
3875 another 0x1000 sized block starting at 0xffffffc00005f000.
3876 ERST
3878 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
3879 "-seed number seed the pseudo-random number generator\n",
3880 QEMU_ARCH_ALL)
3881 SRST
3882 ``-seed number``
3883 Force the guest to use a deterministic pseudo-random number
3884 generator, seeded with number. This does not affect crypto routines
3885 within the host.
3886 ERST
3888 DEF("L", HAS_ARG, QEMU_OPTION_L, \
3889 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
3890 QEMU_ARCH_ALL)
3891 SRST
3892 ``-L path``
3893 Set the directory for the BIOS, VGA BIOS and keymaps.
3895 To list all the data directories, use ``-L help``.
3896 ERST
3898 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3899 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3900 SRST
3901 ``-bios file``
3902 Set the filename for the BIOS.
3903 ERST
3905 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3906 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3907 SRST
3908 ``-enable-kvm``
3909 Enable KVM full virtualization support. This option is only
3910 available if KVM support is enabled when compiling.
3911 ERST
3913 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3914 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL)
3915 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3916 "-xen-attach attach to existing xen domain\n"
3917 " libxl will use this when starting QEMU\n",
3918 QEMU_ARCH_ALL)
3919 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3920 "-xen-domid-restrict restrict set of available xen operations\n"
3921 " to specified domain id. (Does not affect\n"
3922 " xenpv machine type).\n",
3923 QEMU_ARCH_ALL)
3924 SRST
3925 ``-xen-domid id``
3926 Specify xen guest domain id (XEN only).
3928 ``-xen-attach``
3929 Attach to existing xen domain. libxl will use this when starting
3930 QEMU (XEN only). Restrict set of available xen operations to
3931 specified domain id (XEN only).
3932 ERST
3934 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3935 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
3936 SRST
3937 ``-no-reboot``
3938 Exit instead of rebooting.
3939 ERST
3941 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3942 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
3943 SRST
3944 ``-no-shutdown``
3945 Don't exit QEMU on guest shutdown, but instead only stop the
3946 emulation. This allows for instance switching to monitor to commit
3947 changes to the disk image.
3948 ERST
3950 DEF("action", HAS_ARG, QEMU_OPTION_action,
3951 "-action reboot=reset|shutdown\n"
3952 " action when guest reboots [default=reset]\n"
3953 "-action shutdown=poweroff|pause\n"
3954 " action when guest shuts down [default=poweroff]\n"
3955 "-action panic=pause|shutdown|none\n"
3956 " action when guest panics [default=shutdown]\n"
3957 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
3958 " action when watchdog fires [default=reset]\n",
3959 QEMU_ARCH_ALL)
3960 SRST
3961 ``-action event=action``
3962 The action parameter serves to modify QEMU's default behavior when
3963 certain guest events occur. It provides a generic method for specifying the
3964 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown``
3965 parameters.
3967 Examples:
3969 ``-action panic=none``
3970 ``-action reboot=shutdown,shutdown=pause``
3971 ``-watchdog i6300esb -action watchdog=pause``
3973 ERST
3975 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
3976 "-loadvm [tag|id]\n" \
3977 " start right away with a saved state (loadvm in monitor)\n",
3978 QEMU_ARCH_ALL)
3979 SRST
3980 ``-loadvm file``
3981 Start right away with a saved state (``loadvm`` in monitor)
3982 ERST
3984 #ifndef _WIN32
3985 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
3986 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
3987 #endif
3988 SRST
3989 ``-daemonize``
3990 Daemonize the QEMU process after initialization. QEMU will not
3991 detach from standard IO until it is ready to receive connections on
3992 any of its devices. This option is a useful way for external
3993 programs to launch QEMU without having to cope with initialization
3994 race conditions.
3995 ERST
3997 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
3998 "-option-rom rom load a file, rom, into the option ROM space\n",
3999 QEMU_ARCH_ALL)
4000 SRST
4001 ``-option-rom file``
4002 Load the contents of file as an option ROM. This option is useful to
4003 load things like EtherBoot.
4004 ERST
4006 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
4007 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
4008 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
4009 QEMU_ARCH_ALL)
4011 SRST
4012 ``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]``
4013 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at
4014 the current UTC or local time, respectively. ``localtime`` is
4015 required for correct date in MS-DOS or Windows. To start at a
4016 specific point in time, provide datetime in the format
4017 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC.
4019 By default the RTC is driven by the host system time. This allows
4020 using of the RTC as accurate reference clock inside the guest,
4021 specifically if the host time is smoothly following an accurate
4022 external reference clock, e.g. via NTP. If you want to isolate the
4023 guest time from the host, you can set ``clock`` to ``rt`` instead,
4024 which provides a host monotonic clock if host support it. To even
4025 prevent the RTC from progressing during suspension, you can set
4026 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is
4027 recommended especially in icount mode in order to preserve
4028 determinism; however, note that in icount mode the speed of the
4029 virtual clock is variable and can in general differ from the host
4030 clock.
4032 Enable ``driftfix`` (i386 targets only) if you experience time drift
4033 problems, specifically with Windows' ACPI HAL. This option will try
4034 to figure out how many timer interrupts were not processed by the
4035 Windows guest and will re-inject them.
4036 ERST
4038 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
4039 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \
4040 " enable virtual instruction counter with 2^N clock ticks per\n" \
4041 " instruction, enable aligning the host and virtual clocks\n" \
4042 " or disable real time cpu sleeping, and optionally enable\n" \
4043 " record-and-replay mode\n", QEMU_ARCH_ALL)
4044 SRST
4045 ``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]``
4046 Enable virtual instruction counter. The virtual cpu will execute one
4047 instruction every 2^N ns of virtual time. If ``auto`` is specified
4048 then the virtual cpu speed will be automatically adjusted to keep
4049 virtual time within a few seconds of real time.
4051 Note that while this option can give deterministic behavior, it does
4052 not provide cycle accurate emulation. Modern CPUs contain
4053 superscalar out of order cores with complex cache hierarchies. The
4054 number of instructions executed often has little or no correlation
4055 with actual performance.
4057 When the virtual cpu is sleeping, the virtual time will advance at
4058 default speed unless ``sleep=on`` is specified. With
4059 ``sleep=on``, the virtual time will jump to the next timer
4060 deadline instantly whenever the virtual cpu goes to sleep mode and
4061 will not advance if no timer is enabled. This behavior gives
4062 deterministic execution times from the guest point of view.
4063 The default if icount is enabled is ``sleep=off``.
4064 ``sleep=on`` cannot be used together with either ``shift=auto``
4065 or ``align=on``.
4067 ``align=on`` will activate the delay algorithm which will try to
4068 synchronise the host clock and the virtual clock. The goal is to
4069 have a guest running at the real frequency imposed by the shift
4070 option. Whenever the guest clock is behind the host clock and if
4071 ``align=on`` is specified then we print a message to the user to
4072 inform about the delay. Currently this option does not work when
4073 ``shift`` is ``auto``. Note: The sync algorithm will work for those
4074 shift values for which the guest clock runs ahead of the host clock.
4075 Typically this happens when the shift value is high (how high
4076 depends on the host machine). The default if icount is enabled
4077 is ``align=off``.
4079 When the ``rr`` option is specified deterministic record/replay is
4080 enabled. The ``rrfile=`` option must also be provided to
4081 specify the path to the replay log. In record mode data is written
4082 to this file, and in replay mode it is read back.
4083 If the ``rrsnapshot`` option is given then it specifies a VM snapshot
4084 name. In record mode, a new VM snapshot with the given name is created
4085 at the start of execution recording. In replay mode this option
4086 specifies the snapshot name used to load the initial VM state.
4087 ERST
4089 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
4090 "-watchdog model\n" \
4091 " enable virtual hardware watchdog [default=none]\n",
4092 QEMU_ARCH_ALL)
4093 SRST
4094 ``-watchdog model``
4095 Create a virtual hardware watchdog device. Once enabled (by a guest
4096 action), the watchdog must be periodically polled by an agent inside
4097 the guest or else the guest will be restarted. Choose a model for
4098 which your guest has drivers.
4100 The model is the model of hardware watchdog to emulate. Use
4101 ``-watchdog help`` to list available hardware models. Only one
4102 watchdog can be enabled for a guest.
4104 The following models may be available:
4106 ``ib700``
4107 iBASE 700 is a very simple ISA watchdog with a single timer.
4109 ``i6300esb``
4110 Intel 6300ESB I/O controller hub is a much more featureful
4111 PCI-based dual-timer watchdog.
4113 ``diag288``
4114 A virtual watchdog for s390x backed by the diagnose 288
4115 hypercall (currently KVM only).
4116 ERST
4118 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
4119 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
4120 " action when watchdog fires [default=reset]\n",
4121 QEMU_ARCH_ALL)
4122 SRST
4123 ``-watchdog-action action``
4124 The action controls what QEMU will do when the watchdog timer
4125 expires. The default is ``reset`` (forcefully reset the guest).
4126 Other possible actions are: ``shutdown`` (attempt to gracefully
4127 shutdown the guest), ``poweroff`` (forcefully poweroff the guest),
4128 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the
4129 guest), ``debug`` (print a debug message and continue), or ``none``
4130 (do nothing).
4132 Note that the ``shutdown`` action requires that the guest responds
4133 to ACPI signals, which it may not be able to do in the sort of
4134 situations where the watchdog would have expired, and thus
4135 ``-watchdog-action shutdown`` is not recommended for production use.
4137 Examples:
4139 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700``
4141 ERST
4143 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
4144 "-echr chr set terminal escape character instead of ctrl-a\n",
4145 QEMU_ARCH_ALL)
4146 SRST
4147 ``-echr numeric_ascii_value``
4148 Change the escape character used for switching to the monitor when
4149 using monitor and serial sharing. The default is ``0x01`` when using
4150 the ``-nographic`` option. ``0x01`` is equal to pressing
4151 ``Control-a``. You can select a different character from the ascii
4152 control keys where 1 through 26 map to Control-a through Control-z.
4153 For instance you could use the either of the following to change the
4154 escape character to Control-t.
4156 ``-echr 0x14``; \ ``-echr 20``
4158 ERST
4160 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4161 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
4162 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \
4163 "-incoming unix:socketpath\n" \
4164 " prepare for incoming migration, listen on\n" \
4165 " specified protocol and socket address\n" \
4166 "-incoming fd:fd\n" \
4167 "-incoming exec:cmdline\n" \
4168 " accept incoming migration on given file descriptor\n" \
4169 " or from given external command\n" \
4170 "-incoming defer\n" \
4171 " wait for the URI to be specified via migrate_incoming\n",
4172 QEMU_ARCH_ALL)
4173 SRST
4174 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
4176 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
4177 Prepare for incoming migration, listen on a given tcp port.
4179 ``-incoming unix:socketpath``
4180 Prepare for incoming migration, listen on a given unix socket.
4182 ``-incoming fd:fd``
4183 Accept incoming migration from a given filedescriptor.
4185 ``-incoming exec:cmdline``
4186 Accept incoming migration as an output from specified external
4187 command.
4189 ``-incoming defer``
4190 Wait for the URI to be specified via migrate\_incoming. The monitor
4191 can be used to change settings (such as migration parameters) prior
4192 to issuing the migrate\_incoming to allow the migration to begin.
4193 ERST
4195 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4196 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4197 SRST
4198 ``-only-migratable``
4199 Only allow migratable devices. Devices will not be allowed to enter
4200 an unmigratable state.
4201 ERST
4203 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4204 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4205 SRST
4206 ``-nodefaults``
4207 Don't create default devices. Normally, QEMU sets the default
4208 devices like serial port, parallel port, virtual console, monitor
4209 device, VGA adapter, floppy and CD-ROM drive and others. The
4210 ``-nodefaults`` option will disable all those default devices.
4211 ERST
4213 #ifndef _WIN32
4214 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4215 "-chroot dir chroot to dir just before starting the VM\n",
4216 QEMU_ARCH_ALL)
4217 #endif
4218 SRST
4219 ``-chroot dir``
4220 Immediately before starting guest execution, chroot to the specified
4221 directory. Especially useful in combination with -runas.
4222 ERST
4224 #ifndef _WIN32
4225 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4226 "-runas user change to user id user just before starting the VM\n" \
4227 " user can be numeric uid:gid instead\n",
4228 QEMU_ARCH_ALL)
4229 #endif
4230 SRST
4231 ``-runas user``
4232 Immediately before starting guest execution, drop root privileges,
4233 switching to the specified user.
4234 ERST
4236 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4237 "-prom-env variable=value\n"
4238 " set OpenBIOS nvram variables\n",
4239 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4240 SRST
4241 ``-prom-env variable=value``
4242 Set OpenBIOS nvram variable to given value (PPC, SPARC only).
4246 qemu-system-sparc -prom-env 'auto-boot?=false' \
4247 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'