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
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)
18 DEF("version", 0, QEMU_OPTION_version,
19 "-version display version information and exit\n", QEMU_ARCH_ALL)
22 Display version information and exit
25 DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
26 "-machine [type=]name[,prop[=value][,...]]\n"
27 " selects emulated machine ('-machine help' for list)\n"
28 " property accel=accel1[:accel2[:...]] selects accelerator\n"
29 " supported accelerators are kvm, xen, hax, hvf, nvmm, whpx or tcg (default: tcg)\n"
30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n"
31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
32 " mem-merge=on|off controls memory merge support (default: on)\n"
33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
36 " nvdimm=on|off controls NVDIMM support (default=off)\n"
37 " memory-encryption=@var{} memory encryption object to use (default=none)\n"
38 " hmat=on|off controls ACPI HMAT support (default=off)\n"
39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n",
42 ``-machine [type=]name[,prop=value[,...]]``
43 Select the emulated machine by name. Use ``-machine help`` to list
46 For architectures which aim to support live migration compatibility
47 across releases, each release will introduce a new versioned machine
48 type. For example, the 2.8.0 release introduced machine types
49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures.
51 To allow live migration of guests from QEMU version 2.8.0, to QEMU
52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8"
53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to
54 skip multiple intermediate releases when upgrading, new releases of
55 QEMU will support machine types from many previous versions.
57 Supported machine properties are:
59 ``accel=accels1[:accels2[:...]]``
60 This is used to enable an accelerator. Depending on the target
61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available.
62 By default, tcg is used. If there is more than one accelerator
63 specified, the next one is used if the previous one fails to
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.
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
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
92 Enables or disables NVDIMM support. The default is off.
94 ``memory-encryption=``
95 Memory encryption object to use. The default is none.
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.
108 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on
109 -machine memory-backend=pc.ram
112 Migration compatibility note:
114 * as backend id one shall use value of 'default-ram-id', advertised by
115 machine type (available via ``query-machines`` QMP command), if migration
116 to/from old QEMU (<5.0) is expected.
117 * for machine types 4.0 and older, user shall
118 use ``x-use-canonical-path-for-ramblock-id=off`` backend option
119 if migration to/from old QEMU (<5.0) is expected.
124 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off
125 -machine memory-backend=pc.ram
129 DEF("M", HAS_ARG, QEMU_OPTION_M,
130 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n",
134 ``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}``
135 Define an SGX EPC section.
138 DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
139 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
142 Select CPU model (``-cpu help`` for list and additional feature
146 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
147 "-accel [accel=]accelerator[,prop[=value][,...]]\n"
148 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n"
149 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
150 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n"
151 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n"
152 " split-wx=on|off (enable TCG split w^x mapping)\n"
153 " tb-size=n (TCG translation block cache size)\n"
154 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n"
155 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
157 ``-accel name[,prop=value[,...]]``
158 This is used to enable an accelerator. Depending on the target
159 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By
160 default, tcg is used. If there is more than one accelerator
161 specified, the next one is used if the previous one fails to
164 ``igd-passthru=on|off``
165 When Xen is in use, this option controls whether Intel
166 integrated graphics devices can be passed through to the guest
169 ``kernel-irqchip=on|off|split``
170 Controls KVM in-kernel irqchip support. The default is full
171 acceleration of the interrupt controllers. On x86, split irqchip
172 reduces the kernel attack surface, at a performance cost for
173 non-MSI interrupts. Disabling the in-kernel irqchip completely
174 is not recommended except for debugging purposes.
176 ``kvm-shadow-mem=size``
177 Defines the size of the KVM shadow MMU.
180 Controls the use of split w^x mapping for the TCG code generation
181 buffer. Some operating systems require this to be enabled, and in
182 such a case this will default on. On other operating systems, this
183 will default off, but one may enable this for testing or debugging.
186 Controls the size (in MiB) of the TCG translation block cache.
188 ``thread=single|multi``
189 Controls number of TCG threads. When the TCG is multi-threaded
190 there will be one thread per vCPU therefore taking advantage of
191 additional host cores. The default is to enable multi-threading
192 where both the back-end and front-ends support it and no
193 incompatible TCG features have been enabled (e.g.
196 ``dirty-ring-size=n``
197 When the KVM accelerator is used, it controls the size of the per-vCPU
198 dirty page ring buffer (number of entries for each vCPU). It should
199 be a value that is power of two, and it should be 1024 or bigger (but
200 still less than the maximum value that the kernel supports). 4096
201 could be a good initial value if you have no idea which is the best.
202 Set this value to 0 to disable the feature. By default, this feature
203 is disabled (dirty-ring-size=0). When enabled, KVM will instead
204 record dirty pages in a bitmap.
208 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
209 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n"
210 " set the number of initial CPUs to 'n' [default=1]\n"
211 " maxcpus= maximum number of total CPUs, including\n"
212 " offline CPUs for hotplug, etc\n"
213 " sockets= number of sockets on the machine board\n"
214 " dies= number of dies in one socket\n"
215 " clusters= number of clusters in one die\n"
216 " cores= number of cores in one cluster\n"
217 " threads= number of threads in one core\n"
218 "Note: Different machines may have different subsets of the CPU topology\n"
219 " parameters supported, so the actual meaning of the supported parameters\n"
220 " will vary accordingly. For example, for a machine type that supports a\n"
221 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n"
222 " sequentially mean as below:\n"
223 " sockets means the number of sockets on the machine board\n"
224 " cores means the number of cores in one socket\n"
225 " threads means the number of threads in one core\n"
226 " For a particular machine type board, an expected CPU topology hierarchy\n"
227 " can be defined through the supported sub-option. Unsupported parameters\n"
228 " can also be provided in addition to the sub-option, but their values\n"
229 " must be set as 1 in the purpose of correct parsing.\n",
232 ``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]``
233 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on
234 the machine type board. On boards supporting CPU hotplug, the optional
235 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be
236 added at runtime. When both parameters are omitted, the maximum number
237 of CPUs will be calculated from the provided topology members and the
238 initial CPU count will match the maximum number. When only one of them
239 is given then the omitted one will be set to its counterpart's value.
240 Both parameters may be specified, but the maximum number of CPUs must
241 be equal to or greater than the initial CPU count. Product of the
242 CPU topology hierarchy must be equal to the maximum number of CPUs.
243 Both parameters are subject to an upper limit that is determined by
244 the specific machine type chosen.
246 To control reporting of CPU topology information, values of the topology
247 parameters can be specified. Machines may only support a subset of the
248 parameters and different machines may have different subsets supported
249 which vary depending on capacity of the corresponding CPU targets. So
250 for a particular machine type board, an expected topology hierarchy can
251 be defined through the supported sub-option. Unsupported parameters can
252 also be provided in addition to the sub-option, but their values must be
253 set as 1 in the purpose of correct parsing.
255 Either the initial CPU count, or at least one of the topology parameters
256 must be specified. The specified parameters must be greater than zero,
257 explicit configuration like "cpus=0" is not allowed. Values for any
258 omitted parameters will be computed from those which are given.
260 For example, the following sub-option defines a CPU topology hierarchy
261 (2 sockets totally on the machine, 2 cores per socket, 2 threads per
262 core) for a machine that only supports sockets/cores/threads.
263 Some members of the option can be omitted but their values will be
264 automatically computed:
268 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8
270 The following sub-option defines a CPU topology hierarchy (2 sockets
271 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads
272 per core) for PC machines which support sockets/dies/cores/threads.
273 Some members of the option can be omitted but their values will be
274 automatically computed:
278 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16
280 The following sub-option defines a CPU topology hierarchy (2 sockets
281 totally on the machine, 2 clusters per socket, 2 cores per cluster,
282 2 threads per core) for ARM virt machines which support sockets/clusters
283 /cores/threads. Some members of the option can be omitted but their values
284 will be automatically computed:
288 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16
290 Historically preference was given to the coarsest topology parameters
291 when computing missing values (ie sockets preferred over cores, which
292 were preferred over threads), however, this behaviour is considered
293 liable to change. Prior to 6.2 the preference was sockets over cores
294 over threads. Since 6.2 the preference is cores over sockets over threads.
296 For example, the following option defines a machine board with 2 sockets
297 of 1 core before 6.2 and 1 socket of 2 cores after 6.2:
304 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
305 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
306 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
307 "-numa dist,src=source,dst=destination,val=distance\n"
308 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n"
309 "-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"
310 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n",
313 ``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
315 ``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]``
317 ``-numa dist,src=source,dst=destination,val=distance``
319 ``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]``
321 ``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]``
323 ``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]``
324 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA
325 distance from a source node to a destination node. Set the ACPI
326 Heterogeneous Memory Attributes for the given nodes.
328 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and
329 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a
330 contiguous range of CPU indexes (or a single VCPU if lastcpu is
331 omitted). A non-contiguous set of VCPUs can be represented by
332 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is
333 omitted on all nodes, VCPUs are automatically split between them.
335 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a
340 -numa node,cpus=0-2,cpus=5
342 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option
343 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to
344 assign CPU objects to a node using topology layout properties of
345 CPU. The set of properties is machine specific, and depends on used
346 machine type/'\ ``smp``\ ' options. It could be queried with
347 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ '
348 property specifies node to which CPU object will be assigned, it's
349 required for node to be declared with '\ ``node``\ ' option before
350 it's used with '\ ``cpu``\ ' option.
357 -smp 1,sockets=2,maxcpus=2 \
358 -numa node,nodeid=0 -numa node,nodeid=1 \
359 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
361 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported
362 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from
363 a given memory backend device to a node. If '\ ``mem``\ ' and
364 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them.
367 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive.
368 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to
371 '\ ``initiator``\ ' is an additional option that points to an
372 initiator NUMA node that has best performance (the lowest latency or
373 largest bandwidth) to this NUMA node. Note that this option can be
374 set only when the machine property 'hmat' is set to 'on'.
376 Following example creates a machine with 2 NUMA nodes, node 0 has
377 CPU. node 1 has only memory, and its initiator is node 0. Note that
378 because node 0 has CPU, by default the initiator of node 0 is itself
384 -m 2G,slots=2,maxmem=4G \
385 -object memory-backend-ram,size=1G,id=m0 \
386 -object memory-backend-ram,size=1G,id=m1 \
387 -numa node,nodeid=0,memdev=m0 \
388 -numa node,nodeid=1,memdev=m1,initiator=0 \
389 -smp 2,sockets=2,maxcpus=2 \
390 -numa cpu,node-id=0,socket-id=0 \
391 -numa cpu,node-id=0,socket-id=1
393 source and destination are NUMA node IDs. distance is the NUMA
394 distance from source to destination. The distance from a node to
395 itself is always 10. If any pair of nodes is given a distance, then
396 all pairs must be given distances. Although, when distances are only
397 given in one direction for each pair of nodes, then the distances in
398 the opposite directions are assumed to be the same. If, however, an
399 asymmetrical pair of distances is given for even one node pair, then
400 all node pairs must be provided distance values for both directions,
401 even when they are symmetrical. When a node is unreachable from
402 another node, set the pair's distance to 255.
404 Note that the -``numa`` option doesn't allocate any of the specified
405 resources, it just assigns existing resources to NUMA nodes. This
406 means that one still has to use the ``-m``, ``-smp`` options to
407 allocate RAM and VCPUs respectively.
409 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth
410 Information between initiator and target NUMA nodes in ACPI
411 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can
412 create memory requests, usually it has one or more processors.
413 Target NUMA node contains addressable memory.
415 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is
416 the memory hierarchy of the target NUMA node: if hierarchy is
417 'memory', the structure represents the memory performance; if
418 hierarchy is 'first-level\|second-level\|third-level', this
419 structure represents aggregated performance of memory side caches
420 for each domain. type of 'data-type' is type of data represented by
421 this structure instance: if 'hierarchy' is 'memory', 'data-type' is
422 'access\|read\|write' latency or 'access\|read\|write' bandwidth of
423 the target memory; if 'hierarchy' is
424 'first-level\|second-level\|third-level', 'data-type' is
425 'access\|read\|write' hit latency or 'access\|read\|write' hit
426 bandwidth of the target memory side cache.
428 lat is latency value in nanoseconds. bw is bandwidth value, the
429 possible value and units are NUM[M\|G\|T], mean that the bandwidth
430 value are NUM byte per second (or MB/s, GB/s or TB/s depending on
431 used suffix). Note that if latency or bandwidth value is 0, means
432 the corresponding latency or bandwidth information is not provided.
434 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory
435 belongs. size is the size of memory side cache in bytes. level is
436 the cache level described in this structure, note that the cache
437 level 0 should not be used with '\ ``hmat-cache``\ ' option.
438 associativity is the cache associativity, the possible value is
439 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy
440 is the write policy. line is the cache Line size in bytes.
442 For example, the following options describe 2 NUMA nodes. Node 0 has
443 2 cpus and a ram, node 1 has only a ram. The processors in node 0
444 access memory in node 0 with access-latency 5 nanoseconds,
445 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access
446 memory in NUMA node 1 with access-latency 10 nanoseconds,
447 access-bandwidth is 100 MB/s. And for memory side cache information,
448 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB,
449 policy is write-back, the cache Line size is 8 bytes:
455 -object memory-backend-ram,size=1G,id=m0 \
456 -object memory-backend-ram,size=1G,id=m1 \
457 -smp 2,sockets=2,maxcpus=2 \
458 -numa node,nodeid=0,memdev=m0 \
459 -numa node,nodeid=1,memdev=m1,initiator=0 \
460 -numa cpu,node-id=0,socket-id=0 \
461 -numa cpu,node-id=0,socket-id=1 \
462 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \
463 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \
464 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \
465 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \
466 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \
467 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8
470 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
471 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
472 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
474 ``-add-fd fd=fd,set=set[,opaque=opaque]``
475 Add a file descriptor to an fd set. Valid options are:
478 This option defines the file descriptor of which a duplicate is
479 added to fd set. The file descriptor cannot be stdin, stdout, or
483 This option defines the ID of the fd set to add the file
487 This option defines a free-form string that can be used to
490 You can open an image using pre-opened file descriptors from an fd
496 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
497 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
498 -drive file=/dev/fdset/2,index=0,media=disk
501 DEF("set", HAS_ARG, QEMU_OPTION_set,
502 "-set group.id.arg=value\n"
503 " set <arg> parameter for item <id> of type <group>\n"
504 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
506 ``-set group.id.arg=value``
507 Set parameter arg for item id of type group
510 DEF("global", HAS_ARG, QEMU_OPTION_global,
511 "-global driver.property=value\n"
512 "-global driver=driver,property=property,value=value\n"
513 " set a global default for a driver property\n",
516 ``-global driver.prop=value``
518 ``-global driver=driver,property=property,value=value``
519 Set default value of driver's property prop to value, e.g.:
523 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img
525 In particular, you can use this to set driver properties for devices
526 which are created automatically by the machine model. To create a
527 device which is not created automatically and set properties on it,
530 -global driver.prop=value is shorthand for -global
531 driver=driver,property=prop,value=value. The longhand syntax works
532 even when driver contains a dot.
535 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
536 "-boot [order=drives][,once=drives][,menu=on|off]\n"
537 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
538 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
539 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
540 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
541 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
544 ``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]``
545 Specify boot order drives as a string of drive letters. Valid drive
546 letters depend on the target architecture. The x86 PC uses: a, b
547 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p
548 (Etherboot from network adapter 1-4), hard disk boot is the default.
549 To apply a particular boot order only on the first startup, specify
550 it via ``once``. Note that the ``order`` or ``once`` parameter
551 should not be used together with the ``bootindex`` property of
552 devices, since the firmware implementations normally do not support
553 both at the same time.
555 Interactive boot menus/prompts can be enabled via ``menu=on`` as far
556 as firmware/BIOS supports them. The default is non-interactive boot.
558 A splash picture could be passed to bios, enabling user to show it
559 as logo, when option splash=sp\_name is given and menu=on, If
560 firmware/BIOS supports them. Currently Seabios for X86 system
561 support it. limitation: The splash file could be a jpeg file or a
562 BMP file in 24 BPP format(true color). The resolution should be
563 supported by the SVGA mode, so the recommended is 320x240, 640x480,
566 A timeout could be passed to bios, guest will pause for rb\_timeout
567 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will
568 not reboot, qemu passes '-1' to bios by default. Currently Seabios
569 for X86 system support it.
571 Do strict boot via ``strict=on`` as far as firmware/BIOS supports
572 it. This only effects when boot priority is changed by bootindex
573 options. The default is non-strict boot.
577 # try to boot from network first, then from hard disk
578 |qemu_system_x86| -boot order=nc
579 # boot from CD-ROM first, switch back to default order after reboot
580 |qemu_system_x86| -boot once=d
581 # boot with a splash picture for 5 seconds.
582 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000
584 Note: The legacy format '-boot drives' is still supported but its
585 use is discouraged as it may be removed from future versions.
588 DEF("m", HAS_ARG, QEMU_OPTION_m,
589 "-m [size=]megs[,slots=n,maxmem=size]\n"
590 " configure guest RAM\n"
591 " size: initial amount of guest memory\n"
592 " slots: number of hotplug slots (default: none)\n"
593 " maxmem: maximum amount of guest memory (default: none)\n"
594 "NOTE: Some architectures might enforce a specific granularity\n",
597 ``-m [size=]megs[,slots=n,maxmem=size]``
598 Sets guest startup RAM size to megs megabytes. Default is 128 MiB.
599 Optionally, a suffix of "M" or "G" can be used to signify a value in
600 megabytes or gigabytes respectively. Optional pair slots, maxmem
601 could be used to set amount of hotpluggable memory slots and maximum
602 amount of memory. Note that maxmem must be aligned to the page size.
604 For example, the following command-line sets the guest startup RAM
605 size to 1GB, creates 3 slots to hotplug additional memory and sets
606 the maximum memory the guest can reach to 4GB:
610 |qemu_system| -m 1G,slots=3,maxmem=4G
612 If slots and maxmem are not specified, memory hotplug won't be
613 enabled and the guest startup RAM will never increase.
616 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
617 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
620 Allocate guest RAM from a temporarily created file in path.
623 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
624 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
628 Preallocate memory when using -mem-path.
631 DEF("k", HAS_ARG, QEMU_OPTION_k,
632 "-k language use keyboard layout (for example 'fr' for French)\n",
636 Use keyboard layout language (for example ``fr`` for French). This
637 option is only needed where it is not easy to get raw PC keycodes
638 (e.g. on Macs, with some X11 servers or with a VNC or curses
639 display). You don't normally need to use it on PC/Linux or
642 The available layouts are:
646 ar de-ch es fo fr-ca hu ja mk no pt-br sv
647 da en-gb et fr fr-ch is lt nl pl ru th
648 de en-us fi fr-be hr it lv nl-be pt sl tr
650 The default is ``en-us``.
654 HXCOMM Deprecated by -audiodev
655 DEF("audio-help", 0, QEMU_OPTION_audio_help,
656 "-audio-help show -audiodev equivalent of the currently specified audio settings\n",
660 Will show the -audiodev equivalent of the currently specified
661 (deprecated) environment variables.
664 DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
665 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
666 " specifies the audio backend to use\n"
667 " id= identifier of the backend\n"
668 " timer-period= timer period in microseconds\n"
669 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n"
670 " in|out.fixed-settings= use fixed settings for host audio\n"
671 " in|out.frequency= frequency to use with fixed settings\n"
672 " in|out.channels= number of channels to use with fixed settings\n"
673 " in|out.format= sample format to use with fixed settings\n"
674 " valid values: s8, s16, s32, u8, u16, u32, f32\n"
675 " in|out.voices= number of voices to use\n"
676 " in|out.buffer-length= length of buffer in microseconds\n"
677 "-audiodev none,id=id,[,prop[=value][,...]]\n"
678 " dummy driver that discards all output\n"
679 #ifdef CONFIG_AUDIO_ALSA
680 "-audiodev alsa,id=id[,prop[=value][,...]]\n"
681 " in|out.dev= name of the audio device to use\n"
682 " in|out.period-length= length of period in microseconds\n"
683 " in|out.try-poll= attempt to use poll mode\n"
684 " threshold= threshold (in microseconds) when playback starts\n"
686 #ifdef CONFIG_AUDIO_COREAUDIO
687 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
688 " in|out.buffer-count= number of buffers\n"
690 #ifdef CONFIG_AUDIO_DSOUND
691 "-audiodev dsound,id=id[,prop[=value][,...]]\n"
692 " latency= add extra latency to playback in microseconds\n"
694 #ifdef CONFIG_AUDIO_OSS
695 "-audiodev oss,id=id[,prop[=value][,...]]\n"
696 " in|out.dev= path of the audio device to use\n"
697 " in|out.buffer-count= number of buffers\n"
698 " in|out.try-poll= attempt to use poll mode\n"
699 " try-mmap= try using memory mapped access\n"
700 " exclusive= open device in exclusive mode\n"
701 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
703 #ifdef CONFIG_AUDIO_PA
704 "-audiodev pa,id=id[,prop[=value][,...]]\n"
705 " server= PulseAudio server address\n"
706 " in|out.name= source/sink device name\n"
707 " in|out.latency= desired latency in microseconds\n"
709 #ifdef CONFIG_AUDIO_SDL
710 "-audiodev sdl,id=id[,prop[=value][,...]]\n"
711 " in|out.buffer-count= number of buffers\n"
714 "-audiodev spice,id=id[,prop[=value][,...]]\n"
716 #ifdef CONFIG_DBUS_DISPLAY
717 "-audiodev dbus,id=id[,prop[=value][,...]]\n"
719 "-audiodev wav,id=id[,prop[=value][,...]]\n"
720 " path= path of wav file to record\n",
723 ``-audiodev [driver=]driver,id=id[,prop[=value][,...]]``
724 Adds a new audio backend driver identified by id. There are global
725 and driver specific properties. Some values can be set differently
726 for input and output, they're marked with ``in|out.``. You can set
727 the input's property with ``in.prop`` and the output's property with
728 ``out.prop``. For example:
732 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
733 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
735 NOTE: parameter validation is known to be incomplete, in many cases
736 specifying an invalid option causes QEMU to print an error message
737 and continue emulation without sound.
739 Valid global options are:
742 Identifies the audio backend.
744 ``timer-period=period``
745 Sets the timer period used by the audio subsystem in
746 microseconds. Default is 10000 (10 ms).
748 ``in|out.mixing-engine=on|off``
749 Use QEMU's mixing engine to mix all streams inside QEMU and
750 convert audio formats when not supported by the backend. When
751 off, fixed-settings must be off too. Note that disabling this
752 option means that the selected backend must support multiple
753 streams and the audio formats used by the virtual cards,
754 otherwise you'll get no sound. It's not recommended to disable
755 this option unless you want to use 5.1 or 7.1 audio, as mixing
756 engine only supports mono and stereo audio. Default is on.
758 ``in|out.fixed-settings=on|off``
759 Use fixed settings for host audio. When off, it will change
760 based on how the guest opens the sound card. In this case you
761 must not specify frequency, channels or format. Default is on.
763 ``in|out.frequency=frequency``
764 Specify the frequency to use when using fixed-settings. Default
767 ``in|out.channels=channels``
768 Specify the number of channels to use when using fixed-settings.
769 Default is 2 (stereo).
771 ``in|out.format=format``
772 Specify the sample format to use when using fixed-settings.
773 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``,
774 ``u32``, ``f32``. Default is ``s16``.
776 ``in|out.voices=voices``
777 Specify the number of voices to use. Default is 1.
779 ``in|out.buffer-length=usecs``
780 Sets the size of the buffer in microseconds.
782 ``-audiodev none,id=id[,prop[=value][,...]]``
783 Creates a dummy backend that discards all outputs. This backend has
784 no backend specific properties.
786 ``-audiodev alsa,id=id[,prop[=value][,...]]``
787 Creates backend using the ALSA. This backend is only available on
790 ALSA specific options are:
792 ``in|out.dev=device``
793 Specify the ALSA device to use for input and/or output. Default
796 ``in|out.period-length=usecs``
797 Sets the period length in microseconds.
799 ``in|out.try-poll=on|off``
800 Attempt to use poll mode with the device. Default is on.
802 ``threshold=threshold``
803 Threshold (in microseconds) when playback starts. Default is 0.
805 ``-audiodev coreaudio,id=id[,prop[=value][,...]]``
806 Creates a backend using Apple's Core Audio. This backend is only
807 available on Mac OS and only supports playback.
809 Core Audio specific options are:
811 ``in|out.buffer-count=count``
812 Sets the count of the buffers.
814 ``-audiodev dsound,id=id[,prop[=value][,...]]``
815 Creates a backend using Microsoft's DirectSound. This backend is
816 only available on Windows and only supports playback.
818 DirectSound specific options are:
821 Add extra usecs microseconds latency to playback. Default is
824 ``-audiodev oss,id=id[,prop[=value][,...]]``
825 Creates a backend using OSS. This backend is available on most
828 OSS specific options are:
830 ``in|out.dev=device``
831 Specify the file name of the OSS device to use. Default is
834 ``in|out.buffer-count=count``
835 Sets the count of the buffers.
837 ``in|out.try-poll=on|of``
838 Attempt to use poll mode with the device. Default is on.
841 Try using memory mapped device access. Default is off.
844 Open the device in exclusive mode (vmix won't work in this
845 case). Default is off.
847 ``dsp-policy=policy``
848 Sets the timing policy (between 0 and 10, where smaller number
849 means smaller latency but higher CPU usage). Use -1 to use
850 buffer sizes specified by ``buffer`` and ``buffer-count``. This
851 option is ignored if you do not have OSS 4. Default is 5.
853 ``-audiodev pa,id=id[,prop[=value][,...]]``
854 Creates a backend using PulseAudio. This backend is available on
857 PulseAudio specific options are:
860 Sets the PulseAudio server to connect to.
863 Use the specified source/sink for recording/playback.
865 ``in|out.latency=usecs``
866 Desired latency in microseconds. The PulseAudio server will try
867 to honor this value but actual latencies may be lower or higher.
869 ``-audiodev sdl,id=id[,prop[=value][,...]]``
870 Creates a backend using SDL. This backend is available on most
871 systems, but you should use your platform's native backend if
874 SDL specific options are:
876 ``in|out.buffer-count=count``
877 Sets the count of the buffers.
879 ``-audiodev spice,id=id[,prop[=value][,...]]``
880 Creates a backend that sends audio through SPICE. This backend
881 requires ``-spice`` and automatically selected in that case, so
882 usually you can ignore this option. This backend has no backend
885 ``-audiodev wav,id=id[,prop[=value][,...]]``
886 Creates a backend that writes audio to a WAV file.
888 Backend specific options are:
891 Write recorded audio into the specified file. Default is
895 DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
896 "-soundhw c1,... enable audio support\n"
897 " and only specified sound cards (comma separated list)\n"
898 " use '-soundhw help' to get the list of supported cards\n"
899 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
901 ``-soundhw card1[,card2,...] or -soundhw all``
902 Enable audio and selected sound hardware. Use 'help' to print all
903 available sound hardware. For example:
907 |qemu_system_x86| -soundhw sb16,adlib disk.img
908 |qemu_system_x86| -soundhw es1370 disk.img
909 |qemu_system_x86| -soundhw ac97 disk.img
910 |qemu_system_x86| -soundhw hda disk.img
911 |qemu_system_x86| -soundhw all disk.img
912 |qemu_system_x86| -soundhw help
914 Note that Linux's i810\_audio OSS kernel (for AC97) module might
915 require manually specifying clocking.
919 modprobe i810_audio clocking=48000
922 DEF("device", HAS_ARG, QEMU_OPTION_device,
923 "-device driver[,prop[=value][,...]]\n"
924 " add device (based on driver)\n"
925 " prop=value,... sets driver properties\n"
926 " use '-device help' to print all possible drivers\n"
927 " use '-device driver,help' to print all possible properties\n",
930 ``-device driver[,prop[=value][,...]]``
931 Add device driver. prop=value sets driver properties. Valid
932 properties depend on the driver. To get help on possible drivers and
933 properties, use ``-device help`` and ``-device driver,help``.
937 ``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]``
938 Add an IPMI BMC. This is a simulation of a hardware management
939 interface processor that normally sits on a system. It provides a
940 watchdog and the ability to reset and power control the system. You
941 need to connect this to an IPMI interface to make it useful
943 The IPMI slave address to use for the BMC. The default is 0x20. This
944 address is the BMC's address on the I2C network of management
945 controllers. If you don't know what this means, it is safe to ignore
949 The BMC id for interfaces to use this device.
952 Define slave address to use for the BMC. The default is 0x20.
955 file containing raw Sensor Data Records (SDR) data. The default
959 size of a Field Replaceable Unit (FRU) area. The default is
963 file containing raw Field Replaceable Unit (FRU) inventory data.
967 value for the GUID for the BMC, in standard UUID format. If this
968 is set, get "Get GUID" command to the BMC will return it.
969 Otherwise "Get GUID" will return an error.
971 ``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]``
972 Add a connection to an external IPMI BMC simulator. Instead of
973 locally emulating the BMC like the above item, instead connect to an
974 external entity that provides the IPMI services.
976 A connection is made to an external BMC simulator. If you do this,
977 it is strongly recommended that you use the "reconnect=" chardev
978 option to reconnect to the simulator if the connection is lost. Note
979 that if this is not used carefully, it can be a security issue, as
980 the interface has the ability to send resets, NMIs, and power off
981 the VM. It's best if QEMU makes a connection to an external
982 simulator running on a secure port on localhost, so neither the
983 simulator nor QEMU is exposed to any outside network.
985 See the "lanserv/README.vm" file in the OpenIPMI library for more
986 details on the external interface.
988 ``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]``
989 Add a KCS IPMI interafce on the ISA bus. This also adds a
990 corresponding ACPI and SMBIOS entries, if appropriate.
993 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern
997 Define the I/O address of the interface. The default is 0xca0
1001 Define the interrupt to use. The default is 5. To disable
1002 interrupts, set this to 0.
1004 ``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]``
1005 Like the KCS interface, but defines a BT interface. The default port
1006 is 0xe4 and the default interrupt is 5.
1008 ``-device pci-ipmi-kcs,bmc=id``
1009 Add a KCS IPMI interafce on the PCI bus.
1012 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
1014 ``-device pci-ipmi-bt,bmc=id``
1015 Like the KCS interface, but defines a BT interface on the PCI bus.
1017 ``-device intel-iommu[,option=...]``
1018 This is only supported by ``-machine q35``, which will enable Intel VT-d
1019 emulation within the guest. It supports below options:
1021 ``intremap=on|off`` (default: auto)
1022 This enables interrupt remapping feature. It's required to enable
1023 complete x2apic. Currently it only supports kvm kernel-irqchip modes
1024 ``off`` or ``split``, while full kernel-irqchip is not yet supported.
1025 The default value is "auto", which will be decided by the mode of
1028 ``caching-mode=on|off`` (default: off)
1029 This enables caching mode for the VT-d emulated device. When
1030 caching-mode is enabled, each guest DMA buffer mapping will generate an
1031 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in
1032 a synchronous way. It is required for ``-device vfio-pci`` to work
1033 with the VT-d device, because host assigned devices requires to setup
1034 the DMA mapping on the host before guest DMA starts.
1036 ``device-iotlb=on|off`` (default: off)
1037 This enables device-iotlb capability for the emulated VT-d device. So
1038 far virtio/vhost should be the only real user for this parameter,
1039 paired with ats=on configured for the device.
1041 ``aw-bits=39|48`` (default: 39)
1042 This decides the address width of IOVA address space. The address
1043 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for
1044 4-level IOMMU page tables.
1046 Please also refer to the wiki page for general scenarios of VT-d
1047 emulation in QEMU: https://wiki.qemu.org/Features/VT-d.
1051 DEF("name", HAS_ARG, QEMU_OPTION_name,
1052 "-name string1[,process=string2][,debug-threads=on|off]\n"
1053 " set the name of the guest\n"
1054 " string1 sets the window title and string2 the process name\n"
1055 " When debug-threads is enabled, individual threads are given a separate name\n"
1056 " NOTE: The thread names are for debugging and not a stable API.\n",
1060 Sets the name of the guest. This name will be displayed in the SDL
1061 window caption. The name will also be used for the VNC server. Also
1062 optionally set the top visible process name in Linux. Naming of
1063 individual threads can also be enabled on Linux to aid debugging.
1066 DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
1067 "-uuid %08x-%04x-%04x-%04x-%012x\n"
1068 " specify machine UUID\n", QEMU_ARCH_ALL)
1076 DEFHEADING(Block device options:)
1078 DEF("fda", HAS_ARG, QEMU_OPTION_fda,
1079 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
1080 DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
1085 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in
1086 the System Emulation Users Guide).
1089 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
1090 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
1091 DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
1092 DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
1093 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
1094 DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
1103 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images`
1104 chapter in the System Emulation Users Guide).
1107 DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
1108 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
1112 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at
1113 the same time). You can use the host CD-ROM by using ``/dev/cdrom``
1117 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
1118 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
1119 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
1120 " [,read-only=on|off][,auto-read-only=on|off]\n"
1121 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
1122 " [,driver specific parameters...]\n"
1123 " configure a block backend\n", QEMU_ARCH_ALL)
1125 ``-blockdev option[,option[,option[,...]]]``
1126 Define a new block driver node. Some of the options apply to all
1127 block drivers, other options are only accepted for a specific block
1128 driver. See below for a list of generic options and options for the
1129 most common block drivers.
1131 Options that expect a reference to another node (e.g. ``file``) can
1132 be given in two ways. Either you specify the node name of an already
1133 existing node (file=node-name), or you define a new node inline,
1134 adding options for the referenced node after a dot
1135 (file.filename=path,file.aio=native).
1137 A block driver node created with ``-blockdev`` can be used for a
1138 guest device by specifying its node name for the ``drive`` property
1139 in a ``-device`` argument that defines a block device.
1141 ``Valid options for any block driver node:``
1143 Specifies the block driver to use for the given node.
1146 This defines the name of the block driver node by which it
1147 will be referenced later. The name must be unique, i.e. it
1148 must not match the name of a different block driver node, or
1149 (if you use ``-drive`` as well) the ID of a drive.
1151 If no node name is specified, it is automatically generated.
1152 The generated node name is not intended to be predictable
1153 and changes between QEMU invocations. For the top level, an
1154 explicit node name must be specified.
1157 Open the node read-only. Guest write attempts will fail.
1159 Note that some block drivers support only read-only access,
1160 either generally or in certain configurations. In this case,
1161 the default value ``read-only=off`` does not work and the
1162 option must be specified explicitly.
1165 If ``auto-read-only=on`` is set, QEMU may fall back to
1166 read-only usage even when ``read-only=off`` is requested, or
1167 even switch between modes as needed, e.g. depending on
1168 whether the image file is writable or whether a writing user
1169 is attached to the node.
1172 Override the image locking system of QEMU by forcing the
1173 node to utilize weaker shared access for permissions where
1174 it would normally request exclusive access. When there is
1175 the potential for multiple instances to have the same file
1176 open (whether this invocation of QEMU is the first or the
1177 second instance), both instances must permit shared access
1178 for the second instance to succeed at opening the file.
1180 Enabling ``force-share=on`` requires ``read-only=on``.
1183 The host page cache can be avoided with ``cache.direct=on``.
1184 This will attempt to do disk IO directly to the guest's
1185 memory. QEMU may still perform an internal copy of the data.
1188 In case you don't care about data integrity over host
1189 failures, you can use ``cache.no-flush=on``. This option
1190 tells QEMU that it never needs to write any data to the disk
1191 but can instead keep things in cache. If anything goes
1192 wrong, like your host losing power, the disk storage getting
1193 disconnected accidentally, etc. your image will most
1194 probably be rendered unusable.
1197 discard is one of "ignore" (or "off") or "unmap" (or "on")
1198 and controls whether ``discard`` (also known as ``trim`` or
1199 ``unmap``) requests are ignored or passed to the filesystem.
1200 Some machine types may not support discard requests.
1202 ``detect-zeroes=detect-zeroes``
1203 detect-zeroes is "off", "on" or "unmap" and enables the
1204 automatic conversion of plain zero writes by the OS to
1205 driver specific optimized zero write commands. You may even
1206 choose "unmap" if discard is set to "unmap" to allow a zero
1207 write to be converted to an ``unmap`` operation.
1209 ``Driver-specific options for file``
1210 This is the protocol-level block driver for accessing regular
1214 The path to the image file in the local filesystem
1217 Specifies the AIO backend (threads/native/io_uring,
1221 Specifies whether the image file is protected with Linux OFD
1222 / POSIX locks. The default is to use the Linux Open File
1223 Descriptor API if available, otherwise no lock is applied.
1224 (auto/on/off, default: auto)
1230 -blockdev driver=file,node-name=disk,filename=disk.img
1232 ``Driver-specific options for raw``
1233 This is the image format block driver for raw images. It is
1234 usually stacked on top of a protocol level block driver such as
1238 Reference to or definition of the data source block driver
1239 node (e.g. a ``file`` driver node)
1245 -blockdev driver=file,node-name=disk_file,filename=disk.img
1246 -blockdev driver=raw,node-name=disk,file=disk_file
1252 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1254 ``Driver-specific options for qcow2``
1255 This is the image format block driver for qcow2 images. It is
1256 usually stacked on top of a protocol level block driver such as
1260 Reference to or definition of the data source block driver
1261 node (e.g. a ``file`` driver node)
1264 Reference to or definition of the backing file block device
1265 (default is taken from the image file). It is allowed to
1266 pass ``null`` here in order to disable the default backing
1270 Whether to enable the lazy refcounts feature (on/off;
1271 default is taken from the image file)
1274 The maximum total size of the L2 table and refcount block
1275 caches in bytes (default: the sum of l2-cache-size and
1276 refcount-cache-size)
1279 The maximum size of the L2 table cache in bytes (default: if
1280 cache-size is not specified - 32M on Linux platforms, and 8M
1281 on non-Linux platforms; otherwise, as large as possible
1282 within the cache-size, while permitting the requested or the
1283 minimal refcount cache size)
1285 ``refcount-cache-size``
1286 The maximum size of the refcount block cache in bytes
1287 (default: 4 times the cluster size; or if cache-size is
1288 specified, the part of it which is not used for the L2
1291 ``cache-clean-interval``
1292 Clean unused entries in the L2 and refcount caches. The
1293 interval is in seconds. The default value is 600 on
1294 supporting platforms, and 0 on other platforms. Setting it
1295 to 0 disables this feature.
1297 ``pass-discard-request``
1298 Whether discard requests to the qcow2 device should be
1299 forwarded to the data source (on/off; default: on if
1300 discard=unmap is specified, off otherwise)
1302 ``pass-discard-snapshot``
1303 Whether discard requests for the data source should be
1304 issued when a snapshot operation (e.g. deleting a snapshot)
1305 frees clusters in the qcow2 file (on/off; default: on)
1307 ``pass-discard-other``
1308 Whether discard requests for the data source should be
1309 issued on other occasions where a cluster gets freed
1310 (on/off; default: off)
1313 Which overlap checks to perform for writes to the image
1314 (none/constant/cached/all; default: cached). For details or
1315 finer granularity control refer to the QAPI documentation of
1322 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1323 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1329 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1331 ``Driver-specific options for other drivers``
1332 Please refer to the QAPI documentation of the ``blockdev-add``
1336 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1337 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1338 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1339 " [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1340 " [,werror=ignore|stop|report|enospc][,id=name]\n"
1341 " [,aio=threads|native|io_uring]\n"
1342 " [,readonly=on|off][,copy-on-read=on|off]\n"
1343 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1344 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1345 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1346 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1347 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1348 " [[,iops_size=is]]\n"
1350 " use 'file' as a drive image\n", QEMU_ARCH_ALL)
1352 ``-drive option[,option[,option[,...]]]``
1353 Define a new drive. This includes creating a block driver node (the
1354 backend) as well as a guest device, and is mostly a shortcut for
1355 defining the corresponding ``-blockdev`` and ``-device`` options.
1357 ``-drive`` accepts all options that are accepted by ``-blockdev``.
1358 In addition, it knows the following options:
1361 This option defines which disk image (see the :ref:`disk images`
1362 chapter in the System Emulation Users Guide) to use with this drive.
1363 If the filename contains comma, you must double it (for instance,
1364 "file=my,,file" to use file "my,file").
1366 Special files such as iSCSI devices can be specified using
1367 protocol specific URLs. See the section for "Device URL Syntax"
1368 for more information.
1371 This option defines on which type on interface the drive is
1372 connected. Available types are: ide, scsi, sd, mtd, floppy,
1373 pflash, virtio, none.
1375 ``bus=bus,unit=unit``
1376 These options define where is connected the drive by defining
1377 the bus number and the unit id.
1380 This option defines where the drive is connected by using an
1381 index in the list of available connectors of a given interface
1385 This option defines the type of the media: disk or cdrom.
1387 ``snapshot=snapshot``
1388 snapshot is "on" or "off" and controls snapshot mode for the
1389 given drive (see ``-snapshot``).
1392 cache is "none", "writeback", "unsafe", "directsync" or
1393 "writethrough" and controls how the host cache is used to access
1394 block data. This is a shortcut that sets the ``cache.direct``
1395 and ``cache.no-flush`` options (as in ``-blockdev``), and
1396 additionally ``cache.writeback``, which provides a default for
1397 the ``write-cache`` option of block guest devices (as in
1398 ``-device``). The modes correspond to the following settings:
1400 ============= =============== ============ ==============
1401 \ cache.writeback cache.direct cache.no-flush
1402 ============= =============== ============ ==============
1403 writeback on off off
1405 writethrough off off off
1406 directsync off on off
1408 ============= =============== ============ ==============
1410 The default mode is ``cache=writeback``.
1413 aio is "threads", "native", or "io_uring" and selects between pthread
1414 based disk I/O, native Linux AIO, or Linux io_uring API.
1417 Specify which disk format will be used rather than detecting the
1418 format. Can be used to specify format=raw to avoid interpreting
1419 an untrusted format header.
1421 ``werror=action,rerror=action``
1422 Specify which action to take on write and read errors. Valid
1423 actions are: "ignore" (ignore the error and try to continue),
1424 "stop" (pause QEMU), "report" (report the error to the guest),
1425 "enospc" (pause QEMU only if the host disk is full; report the
1426 error to the guest otherwise). The default setting is
1427 ``werror=enospc`` and ``rerror=report``.
1429 ``copy-on-read=copy-on-read``
1430 copy-on-read is "on" or "off" and enables whether to copy read
1431 backing file sectors into the image file.
1433 ``bps=b,bps_rd=r,bps_wr=w``
1434 Specify bandwidth throttling limits in bytes per second, either
1435 for all request types or for reads or writes only. Small values
1436 can lead to timeouts or hangs inside the guest. A safe minimum
1437 for disks is 2 MB/s.
1439 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm``
1440 Specify bursts in bytes per second, either for all request types
1441 or for reads or writes only. Bursts allow the guest I/O to spike
1442 above the limit temporarily.
1444 ``iops=i,iops_rd=r,iops_wr=w``
1445 Specify request rate limits in requests per second, either for
1446 all request types or for reads or writes only.
1448 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm``
1449 Specify bursts in requests per second, either for all request
1450 types or for reads or writes only. Bursts allow the guest I/O to
1451 spike above the limit temporarily.
1454 Let every is bytes of a request count as a new request for iops
1455 throttling purposes. Use this option to prevent guests from
1456 circumventing iops limits by sending fewer but larger requests.
1459 Join a throttling quota group with given name g. All drives that
1460 are members of the same group are accounted for together. Use
1461 this option to prevent guests from circumventing throttling
1462 limits by using many small disks instead of a single larger
1465 By default, the ``cache.writeback=on`` mode is used. It will report
1466 data writes as completed as soon as the data is present in the host
1467 page cache. This is safe as long as your guest OS makes sure to
1468 correctly flush disk caches where needed. If your guest OS does not
1469 handle volatile disk write caches correctly and your host crashes or
1470 loses power, then the guest may experience data corruption.
1472 For such guests, you should consider using ``cache.writeback=off``.
1473 This means that the host page cache will be used to read and write
1474 data, but write notification will be sent to the guest only after
1475 QEMU has made sure to flush each write to the disk. Be aware that
1476 this has a major impact on performance.
1478 When using the ``-snapshot`` option, unsafe caching is always used.
1480 Copy-on-read avoids accessing the same backing file sectors
1481 repeatedly and is useful when the backing file is over a slow
1482 network. By default copy-on-read is off.
1484 Instead of ``-cdrom`` you can use:
1488 |qemu_system| -drive file=file,index=2,media=cdrom
1490 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use:
1494 |qemu_system| -drive file=file,index=0,media=disk
1495 |qemu_system| -drive file=file,index=1,media=disk
1496 |qemu_system| -drive file=file,index=2,media=disk
1497 |qemu_system| -drive file=file,index=3,media=disk
1499 You can open an image using pre-opened file descriptors from an fd
1505 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\
1506 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\
1507 -drive file=/dev/fdset/2,index=0,media=disk
1509 You can connect a CDROM to the slave of ide0:
1513 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom
1515 If you don't specify the "file=" argument, you define an empty
1520 |qemu_system_x86| -drive if=ide,index=1,media=cdrom
1522 Instead of ``-fda``, ``-fdb``, you can use:
1526 |qemu_system_x86| -drive file=file,index=0,if=floppy
1527 |qemu_system_x86| -drive file=file,index=1,if=floppy
1529 By default, interface is "ide" and index is automatically
1534 |qemu_system_x86| -drive file=a -drive file=b"
1536 is interpreted like:
1540 |qemu_system_x86| -hda a -hdb b
1543 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1544 "-mtdblock file use 'file' as on-board Flash memory image\n",
1548 Use file as on-board Flash memory image.
1551 DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1552 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1555 Use file as SecureDigital card image.
1558 DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
1559 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
1562 Use file as a parallel flash image.
1565 DEF("snapshot", 0, QEMU_OPTION_snapshot,
1566 "-snapshot write to temporary files instead of disk image files\n",
1570 Write to temporary files instead of disk image files. In this case,
1571 the raw disk image you use is not written back. You can however
1572 force the write back by pressing C-a s (see the :ref:`disk images`
1573 chapter in the System Emulation Users Guide).
1576 DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1577 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1578 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n"
1579 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1580 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1581 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1582 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1583 " [[,throttling.iops-size=is]]\n"
1584 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n"
1585 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n"
1586 "-fsdev synth,id=id\n",
1590 ``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]``
1592 ``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]``
1594 ``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]``
1596 ``-fsdev synth,id=id[,readonly=on]``
1597 Define a new file system device. Valid options are:
1600 Accesses to the filesystem are done by QEMU.
1603 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1606 Synthetic filesystem, only used by QTests.
1609 Specifies identifier for this device.
1612 Specifies the export path for the file system device. Files
1613 under this path will be available to the 9p client on the guest.
1615 ``security_model=security_model``
1616 Specifies the security model to be used for this export path.
1617 Supported security models are "passthrough", "mapped-xattr",
1618 "mapped-file" and "none". In "passthrough" security model, files
1619 are stored using the same credentials as they are created on the
1620 guest. This requires QEMU to run as root. In "mapped-xattr"
1621 security model, some of the file attributes like uid, gid, mode
1622 bits and link target are stored as file attributes. For
1623 "mapped-file" these attributes are stored in the hidden
1624 .virtfs\_metadata directory. Directories exported by this
1625 security model cannot interact with other unix tools. "none"
1626 security model is same as passthrough except the sever won't
1627 report failures if it fails to set file attributes like
1628 ownership. Security model is mandatory only for local fsdriver.
1629 Other fsdrivers (like proxy) don't take security model as a
1632 ``writeout=writeout``
1633 This is an optional argument. The only supported value is
1634 "immediate". This means that host page cache will be used to
1635 read and write data but write notification will be sent to the
1636 guest only when the data has been reported as written by the
1640 Enables exporting 9p share as a readonly mount for guests. By
1641 default read-write access is given.
1644 Enables proxy filesystem driver to use passed socket file for
1645 communicating with virtfs-proxy-helper(1).
1648 Enables proxy filesystem driver to use passed socket descriptor
1649 for communicating with virtfs-proxy-helper(1). Usually a helper
1650 like libvirt will create socketpair and pass one of the fds as
1654 Specifies the default mode for newly created files on the host.
1655 Works only with security models "mapped-xattr" and
1659 Specifies the default mode for newly created directories on the
1660 host. Works only with security models "mapped-xattr" and
1663 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w``
1664 Specify bandwidth throttling limits in bytes per second, either
1665 for all request types or for reads or writes only.
1667 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm``
1668 Specify bursts in bytes per second, either for all request types
1669 or for reads or writes only. Bursts allow the guest I/O to spike
1670 above the limit temporarily.
1672 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w``
1673 Specify request rate limits in requests per second, either for
1674 all request types or for reads or writes only.
1676 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm``
1677 Specify bursts in requests per second, either for all request
1678 types or for reads or writes only. Bursts allow the guest I/O to
1679 spike above the limit temporarily.
1681 ``throttling.iops-size=is``
1682 Let every is bytes of a request count as a new request for iops
1683 throttling purposes.
1685 -fsdev option is used along with -device driver "virtio-9p-...".
1687 ``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag``
1688 Options for virtio-9p-... driver are:
1691 Specifies the variant to be used. Supported values are "pci",
1692 "ccw" or "device", depending on the machine type.
1695 Specifies the id value specified along with -fsdev option.
1697 ``mount_tag=mount_tag``
1698 Specifies the tag name to be used by the guest to mount this
1702 DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1703 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1704 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n"
1705 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n"
1706 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n"
1707 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n",
1711 ``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]``
1713 ``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1715 ``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]``
1717 ``-virtfs synth,mount_tag=mount_tag``
1718 Define a new virtual filesystem device and expose it to the guest using
1719 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain
1720 directory on host is made directly accessible by guest as a pass-through
1721 file system by using the 9P network protocol for communication between
1722 host and guests, if desired even accessible, shared by several guests
1725 Note that ``-virtfs`` is actually just a convenience shortcut for its
1726 generalized form ``-fsdev -device virtio-9p-pci``.
1728 The general form of pass-through file system options are:
1731 Accesses to the filesystem are done by QEMU.
1734 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1737 Synthetic filesystem, only used by QTests.
1740 Specifies identifier for the filesystem device
1743 Specifies the export path for the file system device. Files
1744 under this path will be available to the 9p client on the guest.
1746 ``security_model=security_model``
1747 Specifies the security model to be used for this export path.
1748 Supported security models are "passthrough", "mapped-xattr",
1749 "mapped-file" and "none". In "passthrough" security model, files
1750 are stored using the same credentials as they are created on the
1751 guest. This requires QEMU to run as root. In "mapped-xattr"
1752 security model, some of the file attributes like uid, gid, mode
1753 bits and link target are stored as file attributes. For
1754 "mapped-file" these attributes are stored in the hidden
1755 .virtfs\_metadata directory. Directories exported by this
1756 security model cannot interact with other unix tools. "none"
1757 security model is same as passthrough except the sever won't
1758 report failures if it fails to set file attributes like
1759 ownership. Security model is mandatory only for local fsdriver.
1760 Other fsdrivers (like proxy) don't take security model as a
1763 ``writeout=writeout``
1764 This is an optional argument. The only supported value is
1765 "immediate". This means that host page cache will be used to
1766 read and write data but write notification will be sent to the
1767 guest only when the data has been reported as written by the
1771 Enables exporting 9p share as a readonly mount for guests. By
1772 default read-write access is given.
1775 Enables proxy filesystem driver to use passed socket file for
1776 communicating with virtfs-proxy-helper(1). Usually a helper like
1777 libvirt will create socketpair and pass one of the fds as
1781 Enables proxy filesystem driver to use passed 'sock\_fd' as the
1782 socket descriptor for interfacing with virtfs-proxy-helper(1).
1785 Specifies the default mode for newly created files on the host.
1786 Works only with security models "mapped-xattr" and
1790 Specifies the default mode for newly created directories on the
1791 host. Works only with security models "mapped-xattr" and
1794 ``mount_tag=mount_tag``
1795 Specifies the tag name to be used by the guest to mount this
1798 ``multidevs=multidevs``
1799 Specifies how to deal with multiple devices being shared with a
1800 9p export. Supported behaviours are either "remap", "forbid" or
1801 "warn". The latter is the default behaviour on which virtfs 9p
1802 expects only one device to be shared with the same export, and
1803 if more than one device is shared and accessed via the same 9p
1804 export then only a warning message is logged (once) by qemu on
1805 host side. In order to avoid file ID collisions on guest you
1806 should either create a separate virtfs export for each device to
1807 be shared with guests (recommended way) or you might use "remap"
1808 instead which allows you to share multiple devices with only one
1809 export instead, which is achieved by remapping the original
1810 inode numbers from host to guest in a way that would prevent
1811 such collisions. Remapping inodes in such use cases is required
1812 because the original device IDs from host are never passed and
1813 exposed on guest. Instead all files of an export shared with
1814 virtfs always share the same device id on guest. So two files
1815 with identical inode numbers but from actually different devices
1816 on host would otherwise cause a file ID collision and hence
1817 potential misbehaviours on guest. "forbid" on the other hand
1818 assumes like "warn" that only one device is shared by the same
1819 export, however it will not only log a warning message but also
1820 deny access to additional devices on guest. Note though that
1821 "forbid" does currently not block all possible file access
1822 operations (e.g. readdir() would still return entries from other
1826 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1827 "-iscsi [user=user][,password=password]\n"
1828 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1829 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1830 " [,timeout=timeout]\n"
1831 " iSCSI session parameters\n", QEMU_ARCH_ALL)
1835 Configure iSCSI session parameters.
1840 DEFHEADING(USB convenience options:)
1842 DEF("usb", 0, QEMU_OPTION_usb,
1843 "-usb enable on-board USB host controller (if not enabled by default)\n",
1847 Enable USB emulation on machine types with an on-board USB host
1848 controller (if not enabled by default). Note that on-board USB host
1849 controllers may not support USB 3.0. In this case
1850 ``-device qemu-xhci`` can be used instead on machines with PCI.
1853 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1854 "-usbdevice name add the host or guest USB device 'name'\n",
1857 ``-usbdevice devname``
1858 Add the USB device devname, and enable an on-board USB controller
1859 if possible and necessary (just like it can be done via
1860 ``-machine usb=on``). Note that this option is mainly intended for
1861 the user's convenience only. More fine-grained control can be
1862 achieved by selecting a USB host controller (if necessary) and the
1863 desired USB device via the ``-device`` option instead. For example,
1864 instead of using ``-usbdevice mouse`` it is possible to use
1865 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse
1866 to a USB 3.0 controller instead (at least on machines that support
1867 PCI and do not have an USB controller enabled by default yet).
1868 For more details, see the chapter about
1869 :ref:`Connecting USB devices` in the System Emulation Users Guide.
1870 Possible devices for devname are:
1873 Braille device. This will use BrlAPI to display the braille
1874 output on a real or fake device (i.e. it also creates a
1875 corresponding ``braille`` chardev automatically beside the
1876 ``usb-braille`` USB device).
1879 Standard USB keyboard. Will override the PS/2 keyboard (if present).
1882 Virtual Mouse. This will override the PS/2 mouse emulation when
1886 Pointer device that uses absolute coordinates (like a
1887 touchscreen). This means QEMU is able to report the mouse
1888 position without having to grab the mouse. Also overrides the
1889 PS/2 mouse emulation when activated.
1892 Wacom PenPartner USB tablet.
1899 DEFHEADING(Display options:)
1901 DEF("display", HAS_ARG, QEMU_OPTION_display,
1902 #if defined(CONFIG_SPICE)
1903 "-display spice-app[,gl=on|off]\n"
1905 #if defined(CONFIG_SDL)
1906 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n"
1907 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n"
1909 #if defined(CONFIG_GTK)
1910 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n"
1911 " [,show-cursor=on|off][,window-close=on|off]\n"
1913 #if defined(CONFIG_VNC)
1914 "-display vnc=<display>[,<optargs>]\n"
1916 #if defined(CONFIG_CURSES)
1917 "-display curses[,charset=<encoding>]\n"
1919 #if defined(CONFIG_COCOA)
1920 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n"
1922 #if defined(CONFIG_OPENGL)
1923 "-display egl-headless[,rendernode=<file>]\n"
1925 #if defined(CONFIG_DBUS_DISPLAY)
1926 "-display dbus[,addr=<dbusaddr>]\n"
1927 " [,gl=on|core|es|off][,rendernode=<file>]\n"
1929 #if defined(CONFIG_COCOA)
1930 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n"
1933 " select display backend type\n"
1934 " The default display is equivalent to\n "
1935 #if defined(CONFIG_GTK)
1936 "\"-display gtk\"\n"
1937 #elif defined(CONFIG_SDL)
1938 "\"-display sdl\"\n"
1939 #elif defined(CONFIG_COCOA)
1940 "\"-display cocoa\"\n"
1941 #elif defined(CONFIG_VNC)
1942 "\"-vnc localhost:0,to=99,id=default\"\n"
1944 "\"-display none\"\n"
1949 Select type of display to use. This option is a replacement for the
1950 old style -sdl/-curses/... options. Use ``-display help`` to list
1951 the available display types. Valid values for type are
1953 ``spice-app[,gl=on|off]``
1954 Start QEMU as a Spice server and launch the default Spice client
1955 application. The Spice server will redirect the serial consoles
1956 and QEMU monitors. (Since 4.0)
1959 Export the display over D-Bus interfaces. (Since 7.0)
1961 The connection is registered with the "org.qemu" name (and queued when
1964 ``addr=<dbusaddr>`` : D-Bus bus address to connect to.
1966 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``.
1968 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface
1969 will share framebuffers with DMABUF file descriptors).
1972 Display video output via SDL (usually in a separate graphics
1973 window; see the SDL documentation for other possibilities).
1974 Valid parameters are:
1976 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling
1977 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be
1978 either ``lshift-lctrl-lalt`` or ``rctrl``.
1980 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing.
1981 This parameter is deprecated - use ``grab-mod`` instead.
1983 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing.
1984 This parameter is deprecated - use ``grab-mod`` instead.
1986 ``gl=on|off|core|es`` : Use OpenGL for displaying
1988 ``show-cursor=on|off`` : Force showing the mouse cursor
1990 ``window-close=on|off`` : Allow to quit qemu with window close button
1993 Display video output in a GTK window. This interface provides
1994 drop-down menus and other UI elements to configure and control
1995 the VM during runtime. Valid parameters are:
1997 ``full-screen=on|off`` : Start in fullscreen mode
1999 ``gl=on|off`` : Use OpenGL for displaying
2001 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover
2003 ``show-cursor=on|off`` : Force showing the mouse cursor
2005 ``window-close=on|off`` : Allow to quit qemu with window close button
2007 ``curses[,charset=<encoding>]``
2008 Display video output via curses. For graphics device models
2009 which support a text mode, QEMU can display this output using a
2010 curses/ncurses interface. Nothing is displayed when the graphics
2011 device is in graphical mode or if the graphics device does not
2012 support a text mode. Generally only the VGA device models
2013 support text mode. The font charset used by the guest can be
2014 specified with the ``charset`` option, for example
2015 ``charset=CP850`` for IBM CP850 encoding. The default is
2019 Display video output in a Cocoa window. Mac only. This interface
2020 provides drop-down menus and other UI elements to configure and
2021 control the VM during runtime. Valid parameters are:
2023 ``show-cursor=on|off`` : Force showing the mouse cursor
2025 ``left-command-key=on|off`` : Disable forwarding left command key to host
2027 ``egl-headless[,rendernode=<file>]``
2028 Offload all OpenGL operations to a local DRI device. For any
2029 graphical display, this display needs to be paired with either
2030 VNC or SPICE displays.
2033 Start a VNC server on display <display>
2036 Do not display video output. The guest will still see an
2037 emulated graphics card, but its output will not be displayed to
2038 the QEMU user. This option differs from the -nographic option in
2039 that it only affects what is done with video output; -nographic
2040 also changes the destination of the serial and parallel port
2044 DEF("nographic", 0, QEMU_OPTION_nographic,
2045 "-nographic disable graphical output and redirect serial I/Os to console\n",
2049 Normally, if QEMU is compiled with graphical window support, it
2050 displays output such as guest graphics, guest console, and the QEMU
2051 monitor in a window. With this option, you can totally disable
2052 graphical output so that QEMU is a simple command line application.
2053 The emulated serial port is redirected on the console and muxed with
2054 the monitor (unless redirected elsewhere explicitly). Therefore, you
2055 can still use QEMU to debug a Linux kernel with a serial console.
2056 Use C-a h for help on switching between the console and monitor.
2059 DEF("curses", 0, QEMU_OPTION_curses,
2060 "-curses shorthand for -display curses\n",
2064 Normally, if QEMU is compiled with graphical window support, it
2065 displays output such as guest graphics, guest console, and the QEMU
2066 monitor in a window. With this option, QEMU can display the VGA
2067 output when in text mode using a curses/ncurses interface. Nothing
2068 is displayed in graphical mode.
2071 DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
2072 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
2076 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that
2077 this also affects the special keys (for fullscreen, monitor-mode
2078 switching, etc). This option is deprecated - please use
2079 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead.
2082 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
2083 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
2087 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this
2088 also affects the special keys (for fullscreen, monitor-mode
2089 switching, etc). This option is deprecated - please use
2090 ``-display sdl,grab-mod=rctrl`` instead.
2093 DEF("sdl", 0, QEMU_OPTION_sdl,
2094 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL)
2100 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
2101 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
2102 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
2103 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
2104 " [,x509-dh-key-file=<file>][,addr=addr]\n"
2105 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n"
2106 " [,tls-ciphers=<list>]\n"
2107 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
2108 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
2109 " [,sasl=on|off][,disable-ticketing=on|off]\n"
2110 " [,password=<string>][,password-secret=<secret-id>]\n"
2111 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
2112 " [,jpeg-wan-compression=[auto|never|always]]\n"
2113 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
2114 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
2115 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
2116 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
2117 " [,gl=[on|off]][,rendernode=<file>]\n"
2119 " at least one of {port, tls-port} is mandatory\n",
2122 ``-spice option[,option[,...]]``
2123 Enable the spice remote desktop protocol. Valid options are
2126 Set the TCP port spice is listening on for plaintext channels.
2129 Set the IP address spice is listening on. Default is any
2132 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off``
2133 Force using the specified IP version.
2135 ``password=<string>``
2136 Set the password you need to authenticate.
2138 This option is deprecated and insecure because it leaves the
2139 password visible in the process listing. Use ``password-secret``
2142 ``password-secret=<secret-id>``
2143 Set the ID of the ``secret`` object containing the password
2144 you need to authenticate.
2147 Require that the client use SASL to authenticate with the spice.
2148 The exact choice of authentication method used is controlled
2149 from the system / user's SASL configuration file for the 'qemu'
2150 service. This is typically found in /etc/sasl2/qemu.conf. If
2151 running QEMU as an unprivileged user, an environment variable
2152 SASL\_CONF\_PATH can be used to make it search alternate
2153 locations for the service config. While some SASL auth methods
2154 can also provide data encryption (eg GSSAPI), it is recommended
2155 that SASL always be combined with the 'tls' and 'x509' settings
2156 to enable use of SSL and server certificates. This ensures a
2157 data encryption preventing compromise of authentication
2160 ``disable-ticketing=on|off``
2161 Allow client connects without authentication.
2163 ``disable-copy-paste=on|off``
2164 Disable copy paste between the client and the guest.
2166 ``disable-agent-file-xfer=on|off``
2167 Disable spice-vdagent based file-xfer between the client and the
2171 Set the TCP port spice is listening on for encrypted channels.
2174 Set the x509 file directory. Expects same filenames as -vnc
2177 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>``
2178 The x509 file names can also be configured individually.
2180 ``tls-ciphers=<list>``
2181 Specify which ciphers to use.
2183 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]``
2184 Force specific channel to be used with or without TLS
2185 encryption. The options can be specified multiple times to
2186 configure multiple channels. The special name "default" can be
2187 used to set the default mode. For channels which are not
2188 explicitly forced into one mode the spice client is allowed to
2189 pick tls/plaintext as he pleases.
2191 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]``
2192 Configure image compression (lossless). Default is auto\_glz.
2194 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]``
2195 Configure wan image compression (lossy for slow links). Default
2198 ``streaming-video=[off|all|filter]``
2199 Configure video stream detection. Default is off.
2201 ``agent-mouse=[on|off]``
2202 Enable/disable passing mouse events via vdagent. Default is on.
2204 ``playback-compression=[on|off]``
2205 Enable/disable audio stream compression (using celt 0.5.1).
2208 ``seamless-migration=[on|off]``
2209 Enable/disable spice seamless migration. Default is off.
2212 Enable/disable OpenGL context. Default is off.
2214 ``rendernode=<file>``
2215 DRM render node for OpenGL rendering. If not specified, it will
2216 pick the first available. (Since 2.9)
2219 DEF("portrait", 0, QEMU_OPTION_portrait,
2220 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
2224 Rotate graphical output 90 deg left (only PXA LCD).
2227 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
2228 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
2232 Rotate graphical output some deg left (only PXA LCD).
2235 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
2236 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
2237 " select video card type\n", QEMU_ARCH_ALL)
2240 Select type of VGA card to emulate. Valid values for type are
2243 Cirrus Logic GD5446 Video card. All Windows versions starting
2244 from Windows 95 should recognize and use this graphic card. For
2245 optimal performances, use 16 bit color depth in the guest and
2246 the host OS. (This card was the default before QEMU 2.2)
2249 Standard VGA card with Bochs VBE extensions. If your guest OS
2250 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if
2251 you want to use high resolution modes (>= 1280x1024x16) then you
2252 should use this option. (This card is the default since QEMU
2256 VMWare SVGA-II compatible adapter. Use it if you have
2257 sufficiently recent XFree86/XOrg server or Windows guest with a
2258 driver for this card.
2261 QXL paravirtual graphic card. It is VGA compatible (including
2262 VESA 2.0 VBE support). Works best with qxl guest drivers
2263 installed though. Recommended choice when using the spice
2267 (sun4m only) Sun TCX framebuffer. This is the default
2268 framebuffer for sun4m machines and offers both 8-bit and 24-bit
2269 colour depths at a fixed resolution of 1024x768.
2272 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit
2273 framebuffer for sun4m machines available in both 1024x768
2274 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people
2275 wishing to run older Solaris versions.
2284 DEF("full-screen", 0, QEMU_OPTION_full_screen,
2285 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
2288 Start in full screen.
2291 DEF("g", HAS_ARG, QEMU_OPTION_g ,
2292 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
2293 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
2295 ``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]``
2296 Set the initial graphical resolution and depth (PPC, SPARC only).
2298 For PPC the default is 800x600x32.
2300 For SPARC with the TCX graphics device, the default is 1024x768x8
2301 with the option of 1024x768x24. For cgthree, the default is
2302 1024x768x8 with the option of 1152x900x8 for people who wish to use
2306 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
2307 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
2309 ``-vnc display[,option[,option[,...]]]``
2310 Normally, if QEMU is compiled with graphical window support, it
2311 displays output such as guest graphics, guest console, and the QEMU
2312 monitor in a window. With this option, you can have QEMU listen on
2313 VNC display display and redirect the VGA display over the VNC
2314 session. It is very useful to enable the usb tablet device when
2315 using this option (option ``-device usb-tablet``). When using the
2316 VNC display, you must use the ``-k`` parameter to set the keyboard
2317 layout if you are not using en-us. Valid syntax for the display is
2320 With this option, QEMU will try next available VNC displays,
2321 until the number L, if the origianlly defined "-vnc display" is
2322 not available, e.g. port 5900+display is already used by another
2323 application. By default, to=0.
2326 TCP connections will only be allowed from host on display d. By
2327 convention the TCP port is 5900+d. Optionally, host can be
2328 omitted in which case the server will accept connections from
2332 Connections will be allowed over UNIX domain sockets where path
2333 is the location of a unix socket to listen for connections on.
2336 VNC is initialized but not started. The monitor ``change``
2337 command can be used to later start the VNC server.
2339 Following the display value there may be one or more option flags
2340 separated by commas. Valid options are
2343 Connect to a listening VNC client via a "reverse" connection.
2344 The client is specified by the display. For reverse network
2345 connections (host:d,``reverse``), the d argument is a TCP port
2346 number, not a display number.
2348 ``websocket=on|off``
2349 Opens an additional TCP listening port dedicated to VNC
2350 Websocket connections. If a bare websocket option is given, the
2351 Websocket port is 5700+display. An alternative port can be
2352 specified with the syntax ``websocket``\ =port.
2354 If host is specified connections will only be allowed from this
2355 host. It is possible to control the websocket listen address
2356 independently, using the syntax ``websocket``\ =host:port.
2358 If no TLS credentials are provided, the websocket connection
2359 runs in unencrypted mode. If TLS credentials are provided, the
2360 websocket connection requires encrypted client connections.
2363 Require that password based authentication is used for client
2366 The password must be set separately using the ``set_password``
2367 command in the :ref:`QEMU monitor`. The
2368 syntax to change your password is:
2369 ``set_password <protocol> <password>`` where <protocol> could be
2370 either "vnc" or "spice".
2372 If you would like to change <protocol> password expiration, you
2373 should use ``expire_password <protocol> <expiration-time>``
2374 where expiration time could be one of the following options:
2375 now, never, +seconds or UNIX time of expiration, e.g. +60 to
2376 make password expire in 60 seconds, or 1335196800 to make
2377 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for
2378 this date and time).
2380 You can also use keywords "now" or "never" for the expiration
2381 time to allow <protocol> password to expire immediately or never
2384 ``password-secret=<secret-id>``
2385 Require that password based authentication is used for client
2386 connections, using the password provided by the ``secret``
2387 object identified by ``secret-id``.
2390 Provides the ID of a set of TLS credentials to use to secure the
2391 VNC server. They will apply to both the normal VNC server socket
2392 and the websocket socket (if enabled). Setting TLS credentials
2393 will cause the VNC server socket to enable the VeNCrypt auth
2394 mechanism. The credentials should have been previously created
2395 using the ``-object tls-creds`` argument.
2398 Provides the ID of the QAuthZ authorization object against which
2399 the client's x509 distinguished name will validated. This object
2400 is only resolved at time of use, so can be deleted and recreated
2401 on the fly while the VNC server is active. If missing, it will
2402 default to denying access.
2405 Require that the client use SASL to authenticate with the VNC
2406 server. The exact choice of authentication method used is
2407 controlled from the system / user's SASL configuration file for
2408 the 'qemu' service. This is typically found in
2409 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user,
2410 an environment variable SASL\_CONF\_PATH can be used to make it
2411 search alternate locations for the service config. While some
2412 SASL auth methods can also provide data encryption (eg GSSAPI),
2413 it is recommended that SASL always be combined with the 'tls'
2414 and 'x509' settings to enable use of SSL and server
2415 certificates. This ensures a data encryption preventing
2416 compromise of authentication credentials. See the
2417 :ref:`VNC security` section in the System Emulation Users Guide
2418 for details on using SASL authentication.
2421 Provides the ID of the QAuthZ authorization object against which
2422 the client's SASL username will validated. This object is only
2423 resolved at time of use, so can be deleted and recreated on the
2424 fly while the VNC server is active. If missing, it will default
2428 Legacy method for enabling authorization of clients against the
2429 x509 distinguished name and SASL username. It results in the
2430 creation of two ``authz-list`` objects with IDs of
2431 ``vnc.username`` and ``vnc.x509dname``. The rules for these
2432 objects must be configured with the HMP ACL commands.
2434 This option is deprecated and should no longer be used. The new
2435 ``sasl-authz`` and ``tls-authz`` options are a replacement.
2438 Enable lossy compression methods (gradient, JPEG, ...). If this
2439 option is set, VNC client may receive lossy framebuffer updates
2440 depending on its encoding settings. Enabling this option can
2441 save a lot of bandwidth at the expense of quality.
2443 ``non-adaptive=on|off``
2444 Disable adaptive encodings. Adaptive encodings are enabled by
2445 default. An adaptive encoding will try to detect frequently
2446 updated screen regions, and send updates in these regions using
2447 a lossy encoding (like JPEG). This can be really helpful to save
2448 bandwidth when playing videos. Disabling adaptive encodings
2449 restores the original static behavior of encodings like Tight.
2451 ``share=[allow-exclusive|force-shared|ignore]``
2452 Set display sharing policy. 'allow-exclusive' allows clients to
2453 ask for exclusive access. As suggested by the rfb spec this is
2454 implemented by dropping other connections. Connecting multiple
2455 clients in parallel requires all clients asking for a shared
2456 session (vncviewer: -shared switch). This is the default.
2457 'force-shared' disables exclusive client access. Useful for
2458 shared desktop sessions, where you don't want someone forgetting
2459 specify -shared disconnect everybody else. 'ignore' completely
2460 ignores the shared flag and allows everybody connect
2461 unconditionally. Doesn't conform to the rfb spec but is
2462 traditional QEMU behavior.
2465 Set keyboard delay, for key down and key up events, in
2466 milliseconds. Default is 10. Keyboards are low-bandwidth
2467 devices, so this slowdown can help the device and guest to keep
2468 up and not lose events in case events are arriving in bulk.
2469 Possible causes for the latter are flaky network connections, or
2470 scripts for automated testing.
2472 ``audiodev=audiodev``
2473 Use the specified audiodev when the VNC client requests audio
2474 transmission. When not using an -audiodev argument, this option
2475 must be omitted, otherwise is must be present and specify a
2478 ``power-control=on|off``
2479 Permit the remote client to issue shutdown, reboot or reset power
2483 ARCHHEADING(, QEMU_ARCH_I386)
2485 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2487 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2488 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2492 Use it when installing Windows 2000 to avoid a disk full bug. After
2493 Windows 2000 is installed, you no longer need this option (this
2494 option slows down the IDE transfers).
2497 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2498 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2502 Disable boot signature checking for floppy disks in BIOS. May be
2503 needed to boot from old floppy disks.
2506 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2507 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2510 Disable ACPI (Advanced Configuration and Power Interface) support.
2511 Use it if your guest OS complains about ACPI problems (PC target
2515 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2516 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2519 Disable HPET support.
2522 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2523 "-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"
2524 " ACPI table description\n", QEMU_ARCH_I386)
2526 ``-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]...]``
2527 Add ACPI table with specified header fields and context from
2528 specified files. For file=, take whole ACPI table from the specified
2529 files, including all ACPI headers (possible overridden by other
2530 options). For data=, only data portion of the table is used, all
2531 header information is specified in the command line. If a SLIC table
2532 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id
2533 fields will override the same in the RSDT and the FADT (a.k.a.
2534 FACP), in order to ensure the field matches required by the
2535 Microsoft SLIC spec and the ACPI spec.
2538 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2539 "-smbios file=binary\n"
2540 " load SMBIOS entry from binary file\n"
2541 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2543 " specify SMBIOS type 0 fields\n"
2544 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2545 " [,uuid=uuid][,sku=str][,family=str]\n"
2546 " specify SMBIOS type 1 fields\n"
2547 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2548 " [,asset=str][,location=str]\n"
2549 " specify SMBIOS type 2 fields\n"
2550 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2552 " specify SMBIOS type 3 fields\n"
2553 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2554 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n"
2555 " [,processor-id=%d]\n"
2556 " specify SMBIOS type 4 fields\n"
2557 "-smbios type=11[,value=str][,path=filename]\n"
2558 " specify SMBIOS type 11 fields\n"
2559 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2560 " [,asset=str][,part=str][,speed=%d]\n"
2561 " specify SMBIOS type 17 fields\n"
2562 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n"
2563 " specify SMBIOS type 41 fields\n",
2564 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2566 ``-smbios file=binary``
2567 Load SMBIOS entry from binary file.
2569 ``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]``
2570 Specify SMBIOS type 0 fields
2572 ``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]``
2573 Specify SMBIOS type 1 fields
2575 ``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]``
2576 Specify SMBIOS type 2 fields
2578 ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
2579 Specify SMBIOS type 3 fields
2581 ``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]``
2582 Specify SMBIOS type 4 fields
2584 ``-smbios type=11[,value=str][,path=filename]``
2585 Specify SMBIOS type 11 fields
2587 This argument can be repeated multiple times, and values are added in the order they are parsed.
2588 Applications intending to use OEM strings data are encouraged to use their application name as
2589 a prefix for the value string. This facilitates passing information for multiple applications
2592 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax
2593 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes.
2595 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to
2596 the SMBIOS table in the order in which they appear.
2598 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535
2599 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the
2600 guest. Instead it should be used as a indicator to inform the guest where to locate the real
2601 data set, for example, by specifying the serial ID of a block device.
2603 An example passing three strings is
2607 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\
2608 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\
2609 path=/some/file/with/oemstringsdata.txt
2611 In the guest OS this is visible with the ``dmidecode`` command
2616 Handle 0x0E00, DMI type 11, 5 bytes
2618 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/
2619 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os
2620 String 3: myapp:some extra data
2623 ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``
2624 Specify SMBIOS type 17 fields
2626 ``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]``
2627 Specify SMBIOS type 41 fields
2629 This argument can be repeated multiple times. Its main use is to allow network interfaces be created
2630 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface
2631 position on the PCI bus.
2633 Here is an example of use:
2637 -netdev user,id=internet \\
2638 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\
2639 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev
2641 In the guest OS, the device should then appear as ``eno1``:
2646 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
2647 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP>
2649 Currently, the PCI device has to be attached to the root bus.
2655 DEFHEADING(Network options:)
2657 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2659 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n"
2660 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2661 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2662 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2663 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2665 "[,smb=dir[,smbserver=addr]]\n"
2667 " configure a user mode network backend with ID 'str',\n"
2668 " its DHCP server and optional services\n"
2671 "-netdev tap,id=str,ifname=name\n"
2672 " configure a host TAP network backend with ID 'str'\n"
2674 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2675 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2676 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2678 " configure a host TAP network backend with ID 'str'\n"
2679 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2680 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2681 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2682 " to deconfigure it\n"
2683 " use '[down]script=no' to disable script execution\n"
2684 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2686 " use 'fd=h' to connect to an already opened TAP interface\n"
2687 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2688 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2689 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2690 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2691 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2692 " use vhost=on to enable experimental in kernel accelerator\n"
2693 " (only has effect for virtio guests which use MSIX)\n"
2694 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2695 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2696 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2697 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2698 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n"
2699 " spent on busy polling for vhost net\n"
2700 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2701 " configure a host TAP network backend with ID 'str' that is\n"
2702 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2703 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2706 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2707 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n"
2708 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n"
2709 " [,rxcookie=rxcookie][,offset=offset]\n"
2710 " configure a network backend with ID 'str' connected to\n"
2711 " an Ethernet over L2TPv3 pseudowire.\n"
2712 " Linux kernel 3.3+ as well as most routers can talk\n"
2713 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2714 " VM to a router and even VM to Host. It is a nearly-universal\n"
2715 " standard (RFC3931). Note - this implementation uses static\n"
2716 " pre-configured tunnels (same as the Linux kernel).\n"
2717 " use 'src=' to specify source address\n"
2718 " use 'dst=' to specify destination address\n"
2719 " use 'udp=on' to specify udp encapsulation\n"
2720 " use 'srcport=' to specify source udp port\n"
2721 " use 'dstport=' to specify destination udp port\n"
2722 " use 'ipv6=on' to force v6\n"
2723 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2724 " well as a weak security measure\n"
2725 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2726 " use 'txcookie=0x012345678' to specify a txcookie\n"
2727 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2728 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2729 " use 'pincounter=on' to work around broken counter handling in peer\n"
2730 " use 'offset=X' to add an extra offset between header and data\n"
2732 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2733 " configure a network backend to connect to another network\n"
2734 " using a socket connection\n"
2735 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2736 " configure a network backend to connect to a multicast maddr and port\n"
2737 " use 'localaddr=addr' to specify the host address to send packets from\n"
2738 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2739 " configure a network backend to connect to another network\n"
2740 " using an UDP tunnel\n"
2742 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2743 " configure a network backend to connect to port 'n' of a vde switch\n"
2744 " running on host and listening for incoming connections on 'socketpath'.\n"
2745 " Use group 'groupname' and mode 'octalmode' to change default\n"
2746 " ownership and permissions for communication port.\n"
2748 #ifdef CONFIG_NETMAP
2749 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2750 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2751 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2752 " netmap device, defaults to '/dev/netmap')\n"
2755 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2756 " configure a vhost-user network, backed by a chardev 'dev'\n"
2759 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n"
2760 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n"
2762 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2763 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2764 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2775 #ifdef CONFIG_NETMAP
2781 "socket][,option][,...][mac=macaddr]\n"
2782 " initialize an on-board / default host NIC (using MAC address\n"
2783 " macaddr) and connect it to the given host network backend\n"
2784 "-nic none use it alone to have zero network devices (the default is to\n"
2785 " provided a 'user' network connection)\n",
2787 DEF("net", HAS_ARG, QEMU_OPTION_net,
2788 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2789 " configure or create an on-board (or machine default) NIC and\n"
2790 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2800 #ifdef CONFIG_NETMAP
2803 "socket][,option][,option][,...]\n"
2804 " old way to initialize a host network interface\n"
2805 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2807 ``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]``
2808 This option is a shortcut for configuring both the on-board
2809 (default) guest NIC hardware and the host network backend in one go.
2810 The host backend options are the same as with the corresponding
2811 ``-netdev`` options below. The guest NIC model can be set with
2812 ``model=modelname``. Use ``model=help`` to list the available device
2813 types. The hardware MAC address can be set with ``mac=macaddr``.
2815 The following two example do exactly the same, to show how ``-nic``
2816 can be used to shorten the command line length:
2820 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2821 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2824 Indicate that no network devices should be configured. It is used to
2825 override the default configuration (default NIC with "user" host
2826 network backend) which is activated if no other networking options
2829 ``-netdev user,id=id[,option][,option][,...]``
2830 Configure user mode host network backend which requires no
2831 administrator privilege to run. Valid options are:
2834 Assign symbolic name for use in monitor commands.
2836 ``ipv4=on|off and ipv6=on|off``
2837 Specify that either IPv4 or IPv6 must be enabled. If neither is
2838 specified both protocols are enabled.
2841 Set IP network address the guest will see. Optionally specify
2842 the netmask, either in the form a.b.c.d or as number of valid
2843 top-most bits. Default is 10.0.2.0/24.
2846 Specify the guest-visible address of the host. Default is the
2847 2nd IP in the guest network, i.e. x.x.x.2.
2849 ``ipv6-net=addr[/int]``
2850 Set IPv6 network address the guest will see (default is
2851 fec0::/64). The network prefix is given in the usual hexadecimal
2852 IPv6 address notation. The prefix size is optional, and is given
2853 as the number of valid top-most bits (default is 64).
2856 Specify the guest-visible IPv6 address of the host. Default is
2857 the 2nd IPv6 in the guest network, i.e. xxxx::2.
2860 If this option is enabled, the guest will be isolated, i.e. it
2861 will not be able to contact the host and no guest IP packets
2862 will be routed over the host to the outside. This option does
2863 not affect any explicitly set forwarding rules.
2866 Specifies the client hostname reported by the built-in DHCP
2870 Specify the first of the 16 IPs the built-in DHCP server can
2871 assign. Default is the 15th to 31st IP in the guest network,
2872 i.e. x.x.x.15 to x.x.x.31.
2875 Specify the guest-visible address of the virtual nameserver. The
2876 address must be different from the host address. Default is the
2877 3rd IP in the guest network, i.e. x.x.x.3.
2880 Specify the guest-visible address of the IPv6 virtual
2881 nameserver. The address must be different from the host address.
2882 Default is the 3rd IP in the guest network, i.e. xxxx::3.
2884 ``dnssearch=domain``
2885 Provides an entry for the domain-search list sent by the
2886 built-in DHCP server. More than one domain suffix can be
2887 transmitted by specifying this option multiple times. If
2888 supported, this will cause the guest to automatically try to
2889 append the given domain suffix(es) in case a domain name can not
2896 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2898 ``domainname=domain``
2899 Specifies the client domain name reported by the built-in DHCP
2903 When using the user mode network stack, activate a built-in TFTP
2904 server. The files in dir will be exposed as the root of a TFTP
2905 server. The TFTP client on the guest must be configured in
2906 binary mode (use the command ``bin`` of the Unix TFTP client).
2908 ``tftp-server-name=name``
2909 In BOOTP reply, broadcast name as the "TFTP server name"
2910 (RFC2132 option 66). This can be used to advise the guest to
2911 load boot files or configurations from a different server than
2915 When using the user mode network stack, broadcast file as the
2916 BOOTP filename. In conjunction with ``tftp``, this can be used
2917 to network boot a guest from a local directory.
2919 Example (using pxelinux):
2923 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\
2924 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2926 ``smb=dir[,smbserver=addr]``
2927 When using the user mode network stack, activate a built-in SMB
2928 server so that Windows OSes can access to the host files in
2929 ``dir`` transparently. The IP address of the SMB server can be
2930 set to addr. By default the 4th IP in the guest network is used,
2933 In the guest Windows OS, the line:
2939 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
2940 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
2943 Then ``dir`` can be accessed in ``\\smbserver\qemu``.
2945 Note that a SAMBA server must be installed on the host OS.
2947 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport``
2948 Redirect incoming TCP or UDP connections to the host port
2949 hostport to the guest IP address guestaddr on guest port
2950 guestport. If guestaddr is not specified, its value is x.x.x.15
2951 (default first address given by the built-in DHCP server). By
2952 specifying hostaddr, the rule can be bound to a specific host
2953 interface. If no connection type is set, TCP is used. This
2954 option can be given multiple times.
2956 For example, to redirect host X11 connection from screen 1 to
2957 guest screen 0, use the following:
2962 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2963 # this host xterm should open in the guest X11 server
2966 To redirect telnet connections from host port 5555 to telnet
2967 port on the guest, use the following:
2972 |qemu_system| -nic user,hostfwd=tcp::5555-:23
2973 telnet localhost 5555
2975 Then when you use on the host ``telnet localhost 5555``, you
2976 connect to the guest telnet server.
2978 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command``
2979 Forward guest TCP connections to the IP address server on port
2980 port to the character device dev or to a program executed by
2981 cmd:command which gets spawned for each connection. This option
2982 can be given multiple times.
2984 You can either use a chardev directly and have that one used
2985 throughout QEMU's lifetime, like in the following example:
2989 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2990 # the guest accesses it
2991 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2993 Or you can execute a command on every TCP connection established
2994 by the guest, so that QEMU behaves similar to an inetd process
2995 for that virtual server:
2999 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
3000 # and connect the TCP stream to its stdin/stdout
3001 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
3003 ``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]``
3004 Configure a host TAP network backend with ID id.
3006 Use the network script file to configure it and the network script
3007 dfile to deconfigure it. If name is not provided, the OS
3008 automatically provides one. The default network configure script is
3009 ``/etc/qemu-ifup`` and the default network deconfigure script is
3010 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to
3011 disable script execution.
3013 If running QEMU as an unprivileged user, use the network helper
3014 to configure the TAP interface and attach it to the bridge.
3015 The default network helper executable is
3016 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3019 ``fd``\ =h can be used to specify the handle of an already opened
3026 #launch a QEMU instance with the default network script
3027 |qemu_system| linux.img -nic tap
3031 #launch a QEMU instance with two NICs, each one connected
3033 |qemu_system| linux.img \\
3034 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\
3035 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
3039 #launch a QEMU instance with the default network helper to
3040 #connect a TAP device to bridge br0
3041 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\
3042 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
3044 ``-netdev bridge,id=id[,br=bridge][,helper=helper]``
3045 Connect a host TAP network interface to a host bridge device.
3047 Use the network helper helper to configure the TAP interface and
3048 attach it to the bridge. The default network helper executable is
3049 ``/path/to/qemu-bridge-helper`` and the default bridge device is
3056 #launch a QEMU instance with the default network helper to
3057 #connect a TAP device to bridge br0
3058 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
3062 #launch a QEMU instance with the default network helper to
3063 #connect a TAP device to bridge qemubr0
3064 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
3066 ``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]``
3067 This host network backend can be used to connect the guest's network
3068 to another QEMU virtual machine using a TCP socket connection. If
3069 ``listen`` is specified, QEMU waits for incoming connections on port
3070 (host is optional). ``connect`` is used to connect to another QEMU
3071 instance using the ``listen`` option. ``fd``\ =h specifies an
3072 already opened TCP socket.
3078 # launch a first QEMU instance
3079 |qemu_system| linux.img \\
3080 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3081 -netdev socket,id=n1,listen=:1234
3082 # connect the network of this instance to the network of the first instance
3083 |qemu_system| linux.img \\
3084 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3085 -netdev socket,id=n2,connect=127.0.0.1:1234
3087 ``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]``
3088 Configure a socket host network backend to share the guest's network
3089 traffic with another QEMU virtual machines using a UDP multicast
3090 socket, effectively making a bus for every QEMU with same multicast
3091 address maddr and port. NOTES:
3093 1. Several QEMU can be running on different hosts and share same bus
3094 (assuming correct multicast setup for these hosts).
3096 2. mcast support is compatible with User Mode Linux (argument
3097 ``ethN=mcast``), see http://user-mode-linux.sf.net.
3099 3. Use ``fd=h`` to specify an already opened UDP multicast socket.
3105 # launch one QEMU instance
3106 |qemu_system| linux.img \\
3107 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3108 -netdev socket,id=n1,mcast=230.0.0.1:1234
3109 # launch another QEMU instance on same "bus"
3110 |qemu_system| linux.img \\
3111 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\
3112 -netdev socket,id=n2,mcast=230.0.0.1:1234
3113 # launch yet another QEMU instance on same "bus"
3114 |qemu_system| linux.img \\
3115 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\
3116 -netdev socket,id=n3,mcast=230.0.0.1:1234
3118 Example (User Mode Linux compat.):
3122 # launch QEMU instance (note mcast address selected is UML's default)
3123 |qemu_system| linux.img \\
3124 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3125 -netdev socket,id=n1,mcast=239.192.168.1:1102
3127 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
3129 Example (send packets from host's 1.2.3.4):
3133 |qemu_system| linux.img \\
3134 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
3135 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
3137 ``-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]``
3138 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
3139 is a popular protocol to transport Ethernet (and other Layer 2) data
3140 frames between two systems. It is present in routers, firewalls and
3141 the Linux kernel (from version 3.3 onwards).
3143 This transport allows a VM to communicate to another VM, router or
3147 source address (mandatory)
3150 destination address (mandatory)
3153 select udp encapsulation (default is ip).
3159 destination udp port.
3162 force v6, otherwise defaults to v4.
3164 ``rxcookie=rxcookie``; \ ``txcookie=txcookie``
3165 Cookies are a weak form of security in the l2tpv3 specification.
3166 Their function is mostly to prevent misconfiguration. By default
3170 Set cookie size to 64 bit instead of the default 32
3173 Force a 'cut-down' L2TPv3 with no counter as in
3174 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
3177 Work around broken counter handling in peer. This may also help
3178 on networks which have packet reorder.
3181 Add an extra offset between header and data
3183 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to
3184 the bridge br-lan on the remote Linux host 1.2.3.4:
3188 # Setup tunnel on linux host using raw ip as encapsulation
3190 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\
3191 encap udp udp_sport 16384 udp_dport 16384
3192 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\
3193 0xFFFFFFFF peer_session_id 0xFFFFFFFF
3194 ifconfig vmtunnel0 mtu 1500
3195 ifconfig vmtunnel0 up
3196 brctl addif br-lan vmtunnel0
3200 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
3202 |qemu_system| linux.img -device e1000,netdev=n1 \\
3203 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
3205 ``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]``
3206 Configure VDE backend to connect to PORT n of a vde switch running
3207 on host and listening for incoming connections on socketpath. Use
3208 GROUP groupname and MODE octalmode to change default ownership and
3209 permissions for communication port. This option is only available if
3210 QEMU has been compiled with vde support enabled.
3217 vde_switch -F -sock /tmp/myswitch
3218 # launch QEMU instance
3219 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch
3221 ``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]``
3222 Establish a vhost-user netdev, backed by a chardev id. The chardev
3223 should be a unix domain socket backed one. The vhost-user uses a
3224 specifically defined protocol to pass vhost ioctl replacement
3225 messages to an application on the other end of the socket. On
3226 non-MSIX guests, the feature can be forced with vhostforce. Use
3227 'queues=n' to specify the number of queues to be created for
3228 multiqueue vhost-user.
3234 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
3235 -numa node,memdev=mem \
3236 -chardev socket,id=chr0,path=/path/to/socket \
3237 -netdev type=vhost-user,id=net0,chardev=chr0 \
3238 -device virtio-net-pci,netdev=net0
3240 ``-netdev vhost-vdpa,vhostdev=/path/to/dev``
3241 Establish a vhost-vdpa netdev.
3243 vDPA device is a device that uses a datapath which complies with
3244 the virtio specifications with a vendor specific control path.
3245 vDPA devices can be both physically located on the hardware or
3246 emulated by software.
3248 ``-netdev hubport,id=id,hubid=hubid[,netdev=nd]``
3249 Create a hub port on the emulated hub with ID hubid.
3251 The hubport netdev lets you connect a NIC to a QEMU emulated hub
3252 instead of a single netdev. Alternatively, you can also connect the
3253 hubport to another netdev with ID nd by using the ``netdev=nd``
3256 ``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]``
3257 Legacy option to configure or create an on-board (or machine
3258 default) Network Interface Card(NIC) and connect it either to the
3259 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd.
3260 If model is omitted, then the default NIC model associated with the
3261 machine type is used. Note that the default NIC model may change in
3262 future QEMU releases, so it is highly recommended to always specify
3263 a model. Optionally, the MAC address can be changed to mac, the
3264 device address set to addr (PCI cards only), and a name can be
3265 assigned for use in monitor commands. Optionally, for PCI cards, you
3266 can specify the number v of MSI-X vectors that the card should have;
3267 this option currently only affects virtio cards; set v = 0 to
3268 disable MSI-X. If no ``-net`` option is specified, a single NIC is
3269 created. QEMU can emulate several different models of network card.
3270 Use ``-net nic,model=help`` for a list of available devices for your
3273 ``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]``
3274 Configure a host network backend (with the options corresponding to
3275 the same ``-netdev`` option) and connect it to the emulated hub 0
3276 (the default hub). Use name to specify the name of the hub port.
3281 DEFHEADING(Character device options:)
3283 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
3285 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3286 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n"
3287 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
3288 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
3289 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
3290 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n"
3291 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
3292 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
3293 " [,logfile=PATH][,logappend=on|off]\n"
3294 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3295 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
3296 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3297 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
3298 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3299 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3301 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3302 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3304 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3305 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
3307 #ifdef CONFIG_BRLAPI
3308 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3310 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
3311 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
3312 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3313 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3315 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
3316 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3317 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
3319 #if defined(CONFIG_SPICE)
3320 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3321 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
3327 The general form of a character device option is:
3329 ``-chardev backend,id=id[,mux=on|off][,options]``
3330 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``,
3331 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``,
3332 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``,
3333 ``spicevmc``, ``spiceport``. The specific backend will determine the
3336 Use ``-chardev help`` to print all available chardev backend types.
3338 All devices must have an id, which can be any string up to 127
3339 characters long. It is used to uniquely identify this device in
3340 other command line directives.
3342 A character device may be used in multiplexing mode by multiple
3343 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is
3344 a "1:N" device, and here the "1" end is your specified chardev
3345 backend, and the "N" end is the various parts of QEMU that can talk
3346 to a chardev. If you create a chardev with ``id=myid`` and
3347 ``mux=on``, QEMU will create a multiplexer with your specified ID,
3348 and you can then configure multiple front ends to use that chardev
3349 ID for their input/output. Up to four different front ends can be
3350 connected to a single multiplexed chardev. (Without multiplexing
3351 enabled, a chardev can only be used by a single front end.) For
3352 instance you could use this to allow a single stdio chardev to be
3353 used by two serial ports and the QEMU monitor:
3357 -chardev stdio,mux=on,id=char0 \
3358 -mon chardev=char0,mode=readline \
3359 -serial chardev:char0 \
3360 -serial chardev:char0
3362 You can have more than one multiplexer in a system configuration;
3363 for instance you could have a TCP port multiplexed between UART 0
3364 and UART 1, and stdio multiplexed between the QEMU monitor and a
3369 -chardev stdio,mux=on,id=char0 \
3370 -mon chardev=char0,mode=readline \
3371 -parallel chardev:char0 \
3372 -chardev tcp,...,mux=on,id=char1 \
3373 -serial chardev:char1 \
3374 -serial chardev:char1
3376 When you're using a multiplexed character device, some escape
3377 sequences are interpreted in the input. See the chapter about
3378 :ref:`keys in the character backend multiplexer` in the
3379 System Emulation Users Guide for more details.
3381 Note that some other command line options may implicitly create
3382 multiplexed character backends; for instance ``-serial mon:stdio``
3383 creates a multiplexed stdio backend connected to the serial port and
3384 the QEMU monitor, and ``-nographic`` also multiplexes the console
3385 and the monitor to stdio.
3387 There is currently no support for multiplexing in the other
3388 direction (where a single QEMU front end takes input and output from
3391 Every backend supports the ``logfile`` option, which supplies the
3392 path to a file to record all data transmitted via the backend. The
3393 ``logappend`` option controls whether the log file will be truncated
3394 or appended to when opened.
3396 The available backends are:
3398 ``-chardev null,id=id``
3399 A void device. This device will not emit any data, and will drop any
3400 data it receives. The null backend does not take any options.
3402 ``-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]``
3403 Create a two-way stream socket, which can be either a TCP or a unix
3404 socket. A unix socket will be created if ``path`` is specified.
3405 Behaviour is undefined if TCP options are specified for a unix
3408 ``server=on|off`` specifies that the socket shall be a listening socket.
3410 ``wait=on|off`` specifies that QEMU should not block waiting for a client
3411 to connect to a listening socket.
3413 ``telnet=on|off`` specifies that traffic on the socket should interpret
3414 telnet escape sequences.
3416 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for
3419 ``reconnect`` sets the timeout for reconnecting on non-server
3420 sockets when the remote end goes away. qemu will delay this many
3421 seconds and then attempt to reconnect. Zero disables reconnecting,
3424 ``tls-creds`` requests enablement of the TLS protocol for
3425 encryption, and specifies the id of the TLS credentials to use for
3426 the handshake. The credentials must be previously created with the
3427 ``-object tls-creds`` argument.
3429 ``tls-auth`` provides the ID of the QAuthZ authorization object
3430 against which the client's x509 distinguished name will be
3431 validated. This object is only resolved at time of use, so can be
3432 deleted and recreated on the fly while the chardev server is active.
3433 If missing, it will default to denying access.
3435 TCP and unix socket options are given below:
3437 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]``
3438 ``host`` for a listening socket specifies the local address to
3439 be bound. For a connecting socket species the remote host to
3440 connect to. ``host`` is optional for listening sockets. If not
3441 specified it defaults to ``0.0.0.0``.
3443 ``port`` for a listening socket specifies the local port to be
3444 bound. For a connecting socket specifies the port on the remote
3445 host to connect to. ``port`` can be given as either a port
3446 number or a service name. ``port`` is required.
3448 ``to`` is only relevant to listening sockets. If it is
3449 specified, and ``port`` cannot be bound, QEMU will attempt to
3450 bind to subsequent ports up to and including ``to`` until it
3451 succeeds. ``to`` must be specified as a port number.
3453 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4
3454 or IPv6 must be used. If neither is specified the socket may
3455 use either protocol.
3457 ``nodelay=on|off`` disables the Nagle algorithm.
3459 ``unix options: path=path[,abstract=on|off][,tight=on|off]``
3460 ``path`` specifies the local path of the unix socket. ``path``
3462 ``abstract=on|off`` specifies the use of the abstract socket namespace,
3463 rather than the filesystem. Optional, defaults to false.
3464 ``tight=on|off`` sets the socket length of abstract sockets to their minimum,
3465 rather than the full sun_path length. Optional, defaults to true.
3467 ``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]``
3468 Sends all traffic from the guest to a remote host over UDP.
3470 ``host`` specifies the remote host to connect to. If not specified
3471 it defaults to ``localhost``.
3473 ``port`` specifies the port on the remote host to connect to.
3474 ``port`` is required.
3476 ``localaddr`` specifies the local address to bind to. If not
3477 specified it defaults to ``0.0.0.0``.
3479 ``localport`` specifies the local port to bind to. If not specified
3480 any available local port will be used.
3482 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used.
3483 If neither is specified the device may use either protocol.
3485 ``-chardev msmouse,id=id``
3486 Forward QEMU's emulated msmouse events to the guest. ``msmouse``
3487 does not take any options.
3489 ``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]``
3490 Connect to a QEMU text console. ``vc`` may optionally be given a
3493 ``width`` and ``height`` specify the width and height respectively
3494 of the console, in pixels.
3496 ``cols`` and ``rows`` specify that the console be sized to fit a
3497 text console with the given dimensions.
3499 ``-chardev ringbuf,id=id[,size=size]``
3500 Create a ring buffer with fixed size ``size``. size must be a power
3501 of two and defaults to ``64K``.
3503 ``-chardev file,id=id,path=path``
3504 Log all traffic received from the guest to a file.
3506 ``path`` specifies the path of the file to be opened. This file will
3507 be created if it does not already exist, and overwritten if it does.
3508 ``path`` is required.
3510 ``-chardev pipe,id=id,path=path``
3511 Create a two-way connection to the guest. The behaviour differs
3512 slightly between Windows hosts and other hosts:
3514 On Windows, a single duplex pipe will be created at
3517 On other hosts, 2 pipes will be created called ``path.in`` and
3518 ``path.out``. Data written to ``path.in`` will be received by the
3519 guest. Data written by the guest can be read from ``path.out``. QEMU
3520 will not create these fifos, and requires them to be present.
3522 ``path`` forms part of the pipe path as described above. ``path`` is
3525 ``-chardev console,id=id``
3526 Send traffic from the guest to QEMU's standard output. ``console``
3527 does not take any options.
3529 ``console`` is only available on Windows hosts.
3531 ``-chardev serial,id=id,path=path``
3532 Send traffic from the guest to a serial device on the host.
3534 On Unix hosts serial will actually accept any tty device, not only
3537 ``path`` specifies the name of the serial device to open.
3539 ``-chardev pty,id=id``
3540 Create a new pseudo-terminal on the host and connect to it. ``pty``
3541 does not take any options.
3543 ``pty`` is not available on Windows hosts.
3545 ``-chardev stdio,id=id[,signal=on|off]``
3546 Connect to standard input and standard output of the QEMU process.
3548 ``signal`` controls if signals are enabled on the terminal, that
3549 includes exiting QEMU with the key sequence Control-c. This option
3550 is enabled by default, use ``signal=off`` to disable it.
3552 ``-chardev braille,id=id``
3553 Connect to a local BrlAPI server. ``braille`` does not take any
3556 ``-chardev tty,id=id,path=path``
3557 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD
3558 and DragonFlyBSD hosts. It is an alias for ``serial``.
3560 ``path`` specifies the path to the tty. ``path`` is required.
3562 ``-chardev parallel,id=id,path=path``
3564 ``-chardev parport,id=id,path=path``
3565 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD
3568 Connect to a local parallel port.
3570 ``path`` specifies the path to the parallel port device. ``path`` is
3573 ``-chardev spicevmc,id=id,debug=debug,name=name``
3574 ``spicevmc`` is only available when spice support is built in.
3576 ``debug`` debug level for spicevmc
3578 ``name`` name of spice channel to connect to
3580 Connect to a spice virtual machine channel, such as vdiport.
3582 ``-chardev spiceport,id=id,debug=debug,name=name``
3583 ``spiceport`` is only available when spice support is built in.
3585 ``debug`` debug level for spicevmc
3587 ``name`` name of spice port to connect to
3589 Connect to a spice port, allowing a Spice client to handle the
3590 traffic identified by a name (preferably a fqdn).
3596 DEFHEADING(TPM device options:)
3598 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3599 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3600 " use path to provide path to a character device; default is /dev/tpm0\n"
3601 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3602 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3603 "-tpmdev emulator,id=id,chardev=dev\n"
3604 " configure the TPM device using chardev backend\n",
3607 The general form of a TPM device option is:
3609 ``-tpmdev backend,id=id[,options]``
3610 The specific backend type will determine the applicable options. The
3611 ``-tpmdev`` option creates the TPM backend and requires a
3612 ``-device`` option that specifies the TPM frontend interface model.
3614 Use ``-tpmdev help`` to print all available TPM backend types.
3616 The available backends are:
3618 ``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path``
3619 (Linux-host only) Enable access to the host's TPM using the
3622 ``path`` specifies the path to the host's TPM device, i.e., on a
3623 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by
3624 default ``/dev/tpm0`` is used.
3626 ``cancel-path`` specifies the path to the host TPM device's sysfs
3627 entry allowing for cancellation of an ongoing TPM command.
3628 ``cancel-path`` is optional and by default QEMU will search for the
3631 Some notes about using the host's TPM with the passthrough driver:
3633 The TPM device accessed by the passthrough driver must not be used
3634 by any other application on the host.
3636 Since the host's firmware (BIOS/UEFI) has already initialized the
3637 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize
3638 the TPM again and may therefore not show a TPM-specific menu that
3639 would otherwise allow the user to configure the TPM, e.g., allow the
3640 user to enable/disable or activate/deactivate the TPM. Further, if
3641 TPM ownership is released from within a VM then the host's TPM will
3642 get disabled and deactivated. To enable and activate the TPM again
3643 afterwards, the host has to be rebooted and the user is required to
3644 enter the firmware's menu to enable and activate the TPM. If the TPM
3645 is left disabled and/or deactivated most TPM commands will fail.
3647 To create a passthrough TPM use the following two options:
3651 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3653 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by
3654 ``tpmdev=tpm0`` in the device option.
3656 ``-tpmdev emulator,id=id,chardev=dev``
3657 (Linux-host only) Enable access to a TPM emulator using Unix domain
3658 socket based chardev backend.
3660 ``chardev`` specifies the unique ID of a character device backend
3661 that provides connection to the software TPM server.
3663 To create a TPM emulator backend device with chardev socket backend:
3667 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3674 DEFHEADING(Linux/Multiboot boot specific:)
3676 When using these options, you can use a given Linux or Multiboot kernel
3677 without installing it in the disk image. It can be useful for easier
3678 testing of various kernels.
3683 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3684 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3687 Use bzImage as kernel image. The kernel can be either a Linux kernel
3688 or in multiboot format.
3691 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3692 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3695 Use cmdline as kernel command line
3698 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3699 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3702 Use file as initial ram disk.
3704 ``-initrd "file1 arg=foo,file2"``
3705 This syntax is only available with multiboot.
3707 Use file1 and file2 as modules and pass arg=foo as parameter to the
3711 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3712 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3715 Use file as a device tree binary (dtb) image and pass it to the
3721 DEFHEADING(Debug/Expert options:)
3723 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
3724 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
3725 " Policy for handling deprecated management interfaces\n"
3726 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n"
3727 " Policy for handling unstable management interfaces\n",
3730 ``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]``
3731 Set policy for handling deprecated management interfaces (experimental):
3733 ``deprecated-input=accept`` (default)
3734 Accept deprecated commands and arguments
3735 ``deprecated-input=reject``
3736 Reject deprecated commands and arguments
3737 ``deprecated-input=crash``
3738 Crash on deprecated commands and arguments
3739 ``deprecated-output=accept`` (default)
3740 Emit deprecated command results and events
3741 ``deprecated-output=hide``
3742 Suppress deprecated command results and events
3744 Limitation: covers only syntactic aspects of QMP.
3746 ``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]``
3747 Set policy for handling unstable management interfaces (experimental):
3749 ``unstable-input=accept`` (default)
3750 Accept unstable commands and arguments
3751 ``unstable-input=reject``
3752 Reject unstable commands and arguments
3753 ``unstable-input=crash``
3754 Crash on unstable commands and arguments
3755 ``unstable-output=accept`` (default)
3756 Emit unstable command results and events
3757 ``unstable-output=hide``
3758 Suppress unstable command results and events
3760 Limitation: covers only syntactic aspects of QMP.
3763 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3764 "-fw_cfg [name=]<name>,file=<file>\n"
3765 " add named fw_cfg entry with contents from file\n"
3766 "-fw_cfg [name=]<name>,string=<str>\n"
3767 " add named fw_cfg entry with contents from string\n",
3770 ``-fw_cfg [name=]name,file=file``
3771 Add named fw\_cfg entry with contents from file file.
3773 ``-fw_cfg [name=]name,string=str``
3774 Add named fw\_cfg entry with contents from string str.
3776 The terminating NUL character of the contents of str will not be
3777 included as part of the fw\_cfg item data. To insert contents with
3778 embedded NUL characters, you have to use the file parameter.
3780 The fw\_cfg entries are passed by QEMU through to the guest.
3786 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3788 creates an fw\_cfg entry named opt/com.mycompany/blob with contents
3789 from ./my\_blob.bin.
3792 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3793 "-serial dev redirect the serial port to char device 'dev'\n",
3797 Redirect the virtual serial port to host character device dev. The
3798 default device is ``vc`` in graphical mode and ``stdio`` in non
3801 This option can be used several times to simulate up to 4 serial
3804 Use ``-serial none`` to disable all serial ports.
3806 Available character devices are:
3809 Virtual console. Optionally, a width and height can be given in
3816 It is also possible to specify width or height in characters:
3823 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3826 No device is allocated.
3832 Use a named character device defined with the ``-chardev``
3836 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial
3837 port parameters are set according to the emulated ones.
3840 [Linux only, parallel port only] Use host parallel port N.
3841 Currently SPP and EPP parallel port features can be used.
3844 Write output to filename. No character can be read.
3847 [Unix only] standard input/output
3853 [Windows only] Use host serial port n
3855 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]``
3856 This implements UDP Net Console. When remote\_host or src\_ip
3857 are not specified they default to ``0.0.0.0``. When not using a
3858 specified src\_port a random port is automatically chosen.
3860 If you just want a simple readonly console you can use
3861 ``netcat`` or ``nc``, by starting QEMU with:
3862 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time
3863 QEMU writes something to that port it will appear in the
3866 If you plan to send characters back via netconsole or you want
3867 to stop and start QEMU a lot of times, you should have QEMU use
3868 the same source port each time by using something like ``-serial
3869 udp::4555@:4556`` to QEMU. Another approach is to use a patched
3870 version of netcat which can listen to a TCP port and send and
3871 receive characters via udp. If you have a patched version of
3872 netcat which activates telnet remote echo and single char
3873 transfer, then you can use the following options to set up a
3874 netcat redirector to allow telnet on port 5555 to access the
3878 -serial udp::4555@:4556
3881 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3886 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]``
3887 The TCP Net Console has two modes of operation. It can send the
3888 serial I/O to a location or wait for a connection from a
3889 location. By default the TCP Net Console is sent to host at the
3890 port. If you use the ``server=on`` option QEMU will wait for a client
3891 socket application to connect to the port before continuing,
3892 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off``
3893 option disables the Nagle buffering algorithm. The ``reconnect=on``
3894 option only applies if ``server=no`` is set, if the connection goes
3895 down it will attempt to reconnect at the given interval. If host
3896 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a
3897 time is accepted. You can use ``telnet=on`` to connect to the
3898 corresponding character device.
3900 ``Example to send tcp console to 192.168.0.2 port 4444``
3901 -serial tcp:192.168.0.2:4444
3903 ``Example to listen and wait on port 4444 for connection``
3904 -serial tcp::4444,server=on
3906 ``Example to not wait and listen on ip 192.168.0.100 port 4444``
3907 -serial tcp:192.168.0.100:4444,server=on,wait=off
3909 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]``
3910 The telnet protocol is used instead of raw tcp sockets. The
3911 options work the same as if you had specified ``-serial tcp``.
3912 The difference is that the port acts like a telnet server or
3913 client using telnet option negotiation. This will also allow you
3914 to send the MAGIC\_SYSRQ sequence if you use a telnet that
3915 supports sending the break sequence. Typically in unix telnet
3916 you do it with Control-] and then type "send break" followed by
3917 pressing the enter key.
3919 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]``
3920 The WebSocket protocol is used instead of raw tcp socket. The
3921 port acts as a WebSocket server. Client mode is not supported.
3923 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]``
3924 A unix domain socket is used instead of a tcp socket. The option
3925 works the same as if you had specified ``-serial tcp`` except
3926 the unix domain socket path is used for connections.
3929 This is a special option to allow the monitor to be multiplexed
3930 onto another serial port. The monitor is accessed with key
3931 sequence of Control-a and then pressing c. dev\_string should be
3932 any one of the serial devices specified above. An example to
3933 multiplex the monitor onto a telnet server listening on port
3936 ``-serial mon:telnet::4444,server=on,wait=off``
3938 When the monitor is multiplexed to stdio in this way, Ctrl+C
3939 will not terminate QEMU any more but will be passed to the guest
3943 Braille device. This will use BrlAPI to display the braille
3944 output on a real or fake device.
3947 Three button serial mouse. Configure the guest to use Microsoft
3951 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3952 "-parallel dev redirect the parallel port to char device 'dev'\n",
3956 Redirect the virtual parallel port to host device dev (same devices
3957 as the serial port). On Linux hosts, ``/dev/parportN`` can be used
3958 to use hardware devices connected on the corresponding host parallel
3961 This option can be used several times to simulate up to 3 parallel
3964 Use ``-parallel none`` to disable all parallel ports.
3967 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3968 "-monitor dev redirect the monitor to char device 'dev'\n",
3972 Redirect the monitor to host device dev (same devices as the serial
3973 port). The default device is ``vc`` in graphical mode and ``stdio``
3974 in non graphical mode. Use ``-monitor none`` to disable the default
3977 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3978 "-qmp dev like -monitor but opens in 'control' mode\n",
3982 Like -monitor but opens in 'control' mode.
3984 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3985 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3989 Like -qmp but uses pretty JSON formatting.
3992 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3993 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3995 ``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]``
3996 Setup monitor on chardev name. ``mode=control`` configures
3997 a QMP monitor (a JSON RPC-style protocol) and it is not the
3998 same as HMP, the human monitor that has a "(qemu)" prompt.
3999 ``pretty`` is only valid when ``mode=control``,
4000 turning on JSON pretty printing to ease
4001 human reading and debugging.
4004 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
4005 "-debugcon dev redirect the debug console to char device 'dev'\n",
4009 Redirect the debug console to host device dev (same devices as the
4010 serial port). The debug console is an I/O port which is typically
4011 port 0xe9; writing to that I/O port sends output to this device. The
4012 default device is ``vc`` in graphical mode and ``stdio`` in non
4016 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
4017 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
4020 Store the QEMU process PID in file. It is useful if you launch QEMU
4024 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
4025 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL)
4028 Run the emulation in single step mode.
4031 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
4032 "--preconfig pause QEMU before machine is initialized (experimental)\n",
4036 Pause QEMU for interactive configuration before the machine is
4037 created, which allows querying and configuring properties that will
4038 affect machine initialization. Use QMP command 'x-exit-preconfig' to
4039 exit the preconfig state and move to the next state (i.e. run guest
4040 if -S isn't used or pause the second time if -S is used). This
4041 option is experimental.
4044 DEF("S", 0, QEMU_OPTION_S, \
4045 "-S freeze CPU at startup (use 'c' to start execution)\n",
4049 Do not start CPU at startup (you must type 'c' in the monitor).
4052 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
4053 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
4054 " run qemu with overcommit hints\n"
4055 " mem-lock=on|off controls memory lock support (default: off)\n"
4056 " cpu-pm=on|off controls cpu power management (default: off)\n",
4059 ``-overcommit mem-lock=on|off``
4061 ``-overcommit cpu-pm=on|off``
4062 Run qemu with hints about host resource overcommit. The default is
4063 to assume that host overcommits all resources.
4065 Locking qemu and guest memory can be enabled via ``mem-lock=on``
4066 (disabled by default). This works when host memory is not
4067 overcommitted and reduces the worst-case latency for guest.
4069 Guest ability to manage power state of host cpus (increasing latency
4070 for other processes on the same host cpu, but decreasing latency for
4071 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This
4072 works best when host CPU is not overcommitted. When used, host
4073 estimates of CPU cycle and power utilization will be incorrect, not
4074 taking into account guest idle time.
4077 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
4078 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n"
4079 " the guest without waiting for gdb to connect; use -S too\n"
4080 " if you want it to not start execution.)\n",
4084 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter
4085 in the System Emulation Users Guide). Note that this option does not pause QEMU
4086 execution -- if you want QEMU to not start the guest until you
4087 connect with gdb and issue a ``continue`` command, you will need to
4088 also pass the ``-S`` option to QEMU.
4090 The most usual configuration is to listen on a local TCP socket::
4094 but you can specify other backends; UDP, pseudo TTY, or even stdio
4095 are all reasonable use cases. For example, a stdio connection
4096 allows you to start QEMU from within gdb and establish the
4097 connection via a pipe:
4101 (gdb) target remote | exec |qemu_system| -gdb stdio ...
4104 DEF("s", 0, QEMU_OPTION_s, \
4105 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
4109 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
4110 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide).
4113 DEF("d", HAS_ARG, QEMU_OPTION_d, \
4114 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
4118 Enable logging of specified items. Use '-d help' for a list of log
4122 DEF("D", HAS_ARG, QEMU_OPTION_D, \
4123 "-D logfile output log to logfile (default stderr)\n",
4127 Output log in logfile instead of to stderr
4130 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
4131 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
4134 ``-dfilter range1[,...]``
4135 Filter debug output to that relevant to a range of target addresses.
4136 The filter spec can be either start+size, start-size or start..end
4137 where start end and size are the addresses and sizes required. For
4142 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
4144 Will dump output for any code in the 0x1000 sized block starting at
4145 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and
4146 another 0x1000 sized block starting at 0xffffffc00005f000.
4149 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
4150 "-seed number seed the pseudo-random number generator\n",
4154 Force the guest to use a deterministic pseudo-random number
4155 generator, seeded with number. This does not affect crypto routines
4159 DEF("L", HAS_ARG, QEMU_OPTION_L, \
4160 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
4164 Set the directory for the BIOS, VGA BIOS and keymaps.
4166 To list all the data directories, use ``-L help``.
4169 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
4170 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
4173 Set the filename for the BIOS.
4176 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
4177 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL)
4180 Enable KVM full virtualization support. This option is only
4181 available if KVM support is enabled when compiling.
4184 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
4185 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL)
4186 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
4187 "-xen-attach attach to existing xen domain\n"
4188 " libxl will use this when starting QEMU\n",
4190 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
4191 "-xen-domid-restrict restrict set of available xen operations\n"
4192 " to specified domain id. (Does not affect\n"
4193 " xenpv machine type).\n",
4197 Specify xen guest domain id (XEN only).
4200 Attach to existing xen domain. libxl will use this when starting
4201 QEMU (XEN only). Restrict set of available xen operations to
4202 specified domain id (XEN only).
4205 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
4206 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
4209 Exit instead of rebooting.
4212 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
4213 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
4216 Don't exit QEMU on guest shutdown, but instead only stop the
4217 emulation. This allows for instance switching to monitor to commit
4218 changes to the disk image.
4221 DEF("action", HAS_ARG, QEMU_OPTION_action,
4222 "-action reboot=reset|shutdown\n"
4223 " action when guest reboots [default=reset]\n"
4224 "-action shutdown=poweroff|pause\n"
4225 " action when guest shuts down [default=poweroff]\n"
4226 "-action panic=pause|shutdown|none\n"
4227 " action when guest panics [default=shutdown]\n"
4228 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
4229 " action when watchdog fires [default=reset]\n",
4232 ``-action event=action``
4233 The action parameter serves to modify QEMU's default behavior when
4234 certain guest events occur. It provides a generic method for specifying the
4235 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown``
4240 ``-action panic=none``
4241 ``-action reboot=shutdown,shutdown=pause``
4242 ``-watchdog i6300esb -action watchdog=pause``
4246 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
4247 "-loadvm [tag|id]\n" \
4248 " start right away with a saved state (loadvm in monitor)\n",
4252 Start right away with a saved state (``loadvm`` in monitor)
4256 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
4257 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
4261 Daemonize the QEMU process after initialization. QEMU will not
4262 detach from standard IO until it is ready to receive connections on
4263 any of its devices. This option is a useful way for external
4264 programs to launch QEMU without having to cope with initialization
4268 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
4269 "-option-rom rom load a file, rom, into the option ROM space\n",
4272 ``-option-rom file``
4273 Load the contents of file as an option ROM. This option is useful to
4274 load things like EtherBoot.
4277 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
4278 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
4279 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
4283 ``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]``
4284 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at
4285 the current UTC or local time, respectively. ``localtime`` is
4286 required for correct date in MS-DOS or Windows. To start at a
4287 specific point in time, provide datetime in the format
4288 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC.
4290 By default the RTC is driven by the host system time. This allows
4291 using of the RTC as accurate reference clock inside the guest,
4292 specifically if the host time is smoothly following an accurate
4293 external reference clock, e.g. via NTP. If you want to isolate the
4294 guest time from the host, you can set ``clock`` to ``rt`` instead,
4295 which provides a host monotonic clock if host support it. To even
4296 prevent the RTC from progressing during suspension, you can set
4297 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is
4298 recommended especially in icount mode in order to preserve
4299 determinism; however, note that in icount mode the speed of the
4300 virtual clock is variable and can in general differ from the host
4303 Enable ``driftfix`` (i386 targets only) if you experience time drift
4304 problems, specifically with Windows' ACPI HAL. This option will try
4305 to figure out how many timer interrupts were not processed by the
4306 Windows guest and will re-inject them.
4309 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
4310 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \
4311 " enable virtual instruction counter with 2^N clock ticks per\n" \
4312 " instruction, enable aligning the host and virtual clocks\n" \
4313 " or disable real time cpu sleeping, and optionally enable\n" \
4314 " record-and-replay mode\n", QEMU_ARCH_ALL)
4316 ``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]``
4317 Enable virtual instruction counter. The virtual cpu will execute one
4318 instruction every 2^N ns of virtual time. If ``auto`` is specified
4319 then the virtual cpu speed will be automatically adjusted to keep
4320 virtual time within a few seconds of real time.
4322 Note that while this option can give deterministic behavior, it does
4323 not provide cycle accurate emulation. Modern CPUs contain
4324 superscalar out of order cores with complex cache hierarchies. The
4325 number of instructions executed often has little or no correlation
4326 with actual performance.
4328 When the virtual cpu is sleeping, the virtual time will advance at
4329 default speed unless ``sleep=on`` is specified. With
4330 ``sleep=on``, the virtual time will jump to the next timer
4331 deadline instantly whenever the virtual cpu goes to sleep mode and
4332 will not advance if no timer is enabled. This behavior gives
4333 deterministic execution times from the guest point of view.
4334 The default if icount is enabled is ``sleep=off``.
4335 ``sleep=on`` cannot be used together with either ``shift=auto``
4338 ``align=on`` will activate the delay algorithm which will try to
4339 synchronise the host clock and the virtual clock. The goal is to
4340 have a guest running at the real frequency imposed by the shift
4341 option. Whenever the guest clock is behind the host clock and if
4342 ``align=on`` is specified then we print a message to the user to
4343 inform about the delay. Currently this option does not work when
4344 ``shift`` is ``auto``. Note: The sync algorithm will work for those
4345 shift values for which the guest clock runs ahead of the host clock.
4346 Typically this happens when the shift value is high (how high
4347 depends on the host machine). The default if icount is enabled
4350 When the ``rr`` option is specified deterministic record/replay is
4351 enabled. The ``rrfile=`` option must also be provided to
4352 specify the path to the replay log. In record mode data is written
4353 to this file, and in replay mode it is read back.
4354 If the ``rrsnapshot`` option is given then it specifies a VM snapshot
4355 name. In record mode, a new VM snapshot with the given name is created
4356 at the start of execution recording. In replay mode this option
4357 specifies the snapshot name used to load the initial VM state.
4360 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
4361 "-watchdog model\n" \
4362 " enable virtual hardware watchdog [default=none]\n",
4366 Create a virtual hardware watchdog device. Once enabled (by a guest
4367 action), the watchdog must be periodically polled by an agent inside
4368 the guest or else the guest will be restarted. Choose a model for
4369 which your guest has drivers.
4371 The model is the model of hardware watchdog to emulate. Use
4372 ``-watchdog help`` to list available hardware models. Only one
4373 watchdog can be enabled for a guest.
4375 The following models may be available:
4378 iBASE 700 is a very simple ISA watchdog with a single timer.
4381 Intel 6300ESB I/O controller hub is a much more featureful
4382 PCI-based dual-timer watchdog.
4385 A virtual watchdog for s390x backed by the diagnose 288
4386 hypercall (currently KVM only).
4389 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
4390 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
4391 " action when watchdog fires [default=reset]\n",
4394 ``-watchdog-action action``
4395 The action controls what QEMU will do when the watchdog timer
4396 expires. The default is ``reset`` (forcefully reset the guest).
4397 Other possible actions are: ``shutdown`` (attempt to gracefully
4398 shutdown the guest), ``poweroff`` (forcefully poweroff the guest),
4399 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the
4400 guest), ``debug`` (print a debug message and continue), or ``none``
4403 Note that the ``shutdown`` action requires that the guest responds
4404 to ACPI signals, which it may not be able to do in the sort of
4405 situations where the watchdog would have expired, and thus
4406 ``-watchdog-action shutdown`` is not recommended for production use.
4410 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700``
4414 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
4415 "-echr chr set terminal escape character instead of ctrl-a\n",
4418 ``-echr numeric_ascii_value``
4419 Change the escape character used for switching to the monitor when
4420 using monitor and serial sharing. The default is ``0x01`` when using
4421 the ``-nographic`` option. ``0x01`` is equal to pressing
4422 ``Control-a``. You can select a different character from the ascii
4423 control keys where 1 through 26 map to Control-a through Control-z.
4424 For instance you could use the either of the following to change the
4425 escape character to Control-t.
4427 ``-echr 0x14``; \ ``-echr 20``
4431 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4432 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
4433 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \
4434 "-incoming unix:socketpath\n" \
4435 " prepare for incoming migration, listen on\n" \
4436 " specified protocol and socket address\n" \
4437 "-incoming fd:fd\n" \
4438 "-incoming exec:cmdline\n" \
4439 " accept incoming migration on given file descriptor\n" \
4440 " or from given external command\n" \
4441 "-incoming defer\n" \
4442 " wait for the URI to be specified via migrate_incoming\n",
4445 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
4447 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
4448 Prepare for incoming migration, listen on a given tcp port.
4450 ``-incoming unix:socketpath``
4451 Prepare for incoming migration, listen on a given unix socket.
4454 Accept incoming migration from a given filedescriptor.
4456 ``-incoming exec:cmdline``
4457 Accept incoming migration as an output from specified external
4461 Wait for the URI to be specified via migrate\_incoming. The monitor
4462 can be used to change settings (such as migration parameters) prior
4463 to issuing the migrate\_incoming to allow the migration to begin.
4466 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4467 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4469 ``-only-migratable``
4470 Only allow migratable devices. Devices will not be allowed to enter
4471 an unmigratable state.
4474 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4475 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4478 Don't create default devices. Normally, QEMU sets the default
4479 devices like serial port, parallel port, virtual console, monitor
4480 device, VGA adapter, floppy and CD-ROM drive and others. The
4481 ``-nodefaults`` option will disable all those default devices.
4485 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4486 "-chroot dir chroot to dir just before starting the VM\n",
4491 Immediately before starting guest execution, chroot to the specified
4492 directory. Especially useful in combination with -runas.
4496 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4497 "-runas user change to user id user just before starting the VM\n" \
4498 " user can be numeric uid:gid instead\n",
4503 Immediately before starting guest execution, drop root privileges,
4504 switching to the specified user.
4507 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4508 "-prom-env variable=value\n"
4509 " set OpenBIOS nvram variables\n",
4510 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4512 ``-prom-env variable=value``
4513 Set OpenBIOS nvram variable to given value (PPC, SPARC only).
4517 qemu-system-sparc -prom-env 'auto-boot?=false' \
4518 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
4522 qemu-system-ppc -prom-env 'auto-boot?=false' \
4523 -prom-env 'boot-device=hd:2,\yaboot' \
4524 -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
4526 DEF("semihosting", 0, QEMU_OPTION_semihosting,
4527 "-semihosting semihosting mode\n",
4528 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4529 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4532 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only).
4534 Note that this allows guest direct access to the host filesystem, so
4535 should only be used with a trusted guest OS.
4537 See the -semihosting-config option documentation for further
4538 information about the facilities this enables.
4540 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4541 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
4542 " semihosting configuration\n",
4543 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA |
4544 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV)
4546 ``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]``
4547 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V
4550 Note that this allows guest direct access to the host filesystem, so
4551 should only be used with a trusted guest OS.
4553 On Arm this implements the standard semihosting API, version 2.0.
4555 On M68K this implements the "ColdFire GDB" interface used by
4558 Xtensa semihosting provides basic file IO calls, such as
4559 open/read/write/seek/select. Tensilica baremetal libc for ISS and
4560 linux platform "sim" use this interface.
4562 On RISC-V this implements the standard semihosting API, version 0.2.
4564 ``target=native|gdb|auto``
4565 Defines where the semihosting calls will be addressed, to QEMU
4566 (``native``) or to GDB (``gdb``). The default is ``auto``, which
4567 means ``gdb`` during debug sessions and ``native`` otherwise.
4570 Send the output to a chardev backend output for native or auto
4571 output when not in gdb
4573 ``arg=str1,arg=str2,...``
4574 Allows the user to pass input arguments, and can be used
4575 multiple times to build up a list. The old-style
4576 ``-kernel``/``-append`` method of passing a command line is
4577 still supported for backward compatibility. If both the
4578 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are
4579 specified, the former is passed to semihosting as it always
4582 DEF("old-param", 0, QEMU_OPTION_old_param,
4583 "-old-param old param mode\n", QEMU_ARCH_ARM)
4586 Old param mode (ARM only).
4589 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4590 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4591 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4592 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4593 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4594 " by the kernel, but typically no longer used by modern\n" \
4595 " C library implementations.\n" \
4596 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \
4597 " to elevate privileges using set*uid|gid system calls.\n" \
4598 " The value 'children' will deny set*uid|gid system calls for\n" \
4599 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4600 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4601 " blocking *fork and execve\n" \
4602 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4605 ``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]``
4606 Enable Seccomp mode 2 system call filter. 'on' will enable syscall
4607 filtering and 'off' will disable it. The default is 'off'.
4610 Enable Obsolete system calls
4612 ``elevateprivileges=string``
4613 Disable set\*uid\|gid system calls
4616 Disable \*fork and execve
4618 ``resourcecontrol=string``
4619 Disable process affinity and schedular priority
4622 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4623 "-readconfig <file>\n", QEMU_ARCH_ALL)
4625 ``-readconfig file``
4626 Read device configuration from file. This approach is useful when
4627 you want to spawn QEMU process with many command line options but
4628 you don't want to exceed the command line character limit.
4630 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
4631 "-writeconfig <file>\n"
4632 " read/write config file (deprecated)\n", QEMU_ARCH_ALL)
4636 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4638 " do not load default user-provided config files at startup\n",
4642 The ``-no-user-config`` option makes QEMU not load any of the
4643 user-provided config files on sysconfdir.
4646 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4647 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4648 " specify tracing options\n",
4651 ``-trace [[enable=]pattern][,events=file][,file=file]``
4652 .. include:: ../qemu-option-trace.rst.inc
4655 DEF("plugin", HAS_ARG, QEMU_OPTION_plugin,
4656 "-plugin [file=]<file>[,<argname>=<argvalue>]\n"
4660 ``-plugin file=file[,argname=argvalue]``
4664 Load the given plugin from a shared library file.
4666 ``argname=argvalue``
4667 Argument passed to the plugin. (Can be given multiple times.)
4671 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4672 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4675 DEF("enable-fips", 0, QEMU_OPTION_enablefips,
4676 "-enable-fips enable FIPS 140-2 compliance\n",
4681 Enable FIPS 140-2 compliance mode.
4684 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4685 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
4686 " control error message format\n"
4687 " timestamp=on enables timestamps (default: off)\n"
4688 " guest-name=on enables guest name prefix but only if\n"
4689 " -name guest option is set (default: off)\n",
4692 ``-msg [timestamp[=on|off]][,guest-name[=on|off]]``
4693 Control error message format.
4695 ``timestamp=on|off``
4696 Prefix messages with a timestamp. Default is off.
4698 ``guest-name=on|off``
4699 Prefix messages with guest name but only if -name guest option is set
4700 otherwise the option is ignored. Default is off.
4703 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4704 "-dump-vmstate <file>\n"
4705 " Output vmstate information in JSON format to file.\n"
4706 " Use the scripts/vmstate-static-checker.py file to\n"
4707 " check for possible regressions in migration code\n"
4708 " by comparing two such vmstate dumps.\n",
4711 ``-dump-vmstate file``
4712 Dump json-encoded vmstate information for current machine type to
4716 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4717 "-enable-sync-profile\n"
4718 " enable synchronization profiling\n",
4721 ``-enable-sync-profile``
4722 Enable synchronization profiling.
4727 DEFHEADING(Generic object creation:)
4729 DEF("object", HAS_ARG, QEMU_OPTION_object,
4730 "-object TYPENAME[,PROP1=VALUE1,...]\n"
4731 " create a new object of type TYPENAME setting properties\n"
4732 " in the order they are specified. Note that the 'id'\n"
4733 " property must be set. These objects are placed in the\n"
4734 " '/objects' path.\n",
4737 ``-object typename[,prop1=value1,...]``
4738 Create a new object of type typename setting properties in the order
4739 they are specified. Note that the 'id' property must be set. These
4740 objects are placed in the '/objects' path.
4742 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off``
4743 Creates a memory file backend object, which can be used to back
4744 the guest RAM with huge pages.
4746 The ``id`` parameter is a unique ID that will be used to
4747 reference this memory region in other parameters, e.g. ``-numa``,
4748 ``-device nvdimm``, etc.
4750 The ``size`` option provides the size of the memory region, and
4751 accepts common suffixes, e.g. ``500M``.
4753 The ``mem-path`` provides the path to either a shared memory or
4754 huge page filesystem mount.
4756 The ``share`` boolean option determines whether the memory
4757 region is marked as private to QEMU, or shared. The latter
4758 allows a co-operating external process to access the QEMU memory
4761 The ``share`` is also required for pvrdma devices due to
4762 limitations in the RDMA API provided by Linux.
4764 Setting share=on might affect the ability to configure NUMA
4765 bindings for the memory backend under some circumstances, see
4766 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel
4767 source tree for additional details.
4769 Setting the ``discard-data`` boolean option to on indicates that
4770 file contents can be destroyed when QEMU exits, to avoid
4771 unnecessarily flushing data to the backing file. Note that
4772 ``discard-data`` is only an optimization, and QEMU might not
4773 discard file contents if it aborts unexpectedly or is terminated
4776 The ``merge`` boolean option enables memory merge, also known as
4777 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider
4778 the pages for memory deduplication.
4780 Setting the ``dump`` boolean option to off excludes the memory
4781 from core dumps. This feature is also known as MADV\_DONTDUMP.
4783 The ``prealloc`` boolean option enables memory preallocation.
4785 The ``host-nodes`` option binds the memory range to a list of
4788 The ``policy`` option sets the NUMA policy to one of the
4795 prefer the given host node list for allocation
4798 restrict memory allocation to the given host node list
4801 interleave memory allocations across the given host node
4804 The ``align`` option specifies the base address alignment when
4805 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg
4806 ``2M``. Some backend store specified by ``mem-path`` requires an
4807 alignment different than the default one used by QEMU, eg the
4808 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4809 such cases, users can specify the required alignment via this
4812 The ``pmem`` option specifies whether the backing file specified
4813 by ``mem-path`` is in host persistent memory that can be
4814 accessed using the SNIA NVM programming model (e.g. Intel
4815 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary
4816 operations to guarantee the persistence of its own writes to
4817 ``mem-path`` (e.g. in vNVDIMM label emulation and live
4818 migration). Also, we will map the backend-file with MAP\_SYNC
4819 flag, which ensures the file metadata is in sync for
4820 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC
4821 requires support from both the host kernel (since Linux kernel
4822 4.15) and the filesystem of ``mem-path`` mounted with DAX
4825 The ``readonly`` option specifies whether the backing file is opened
4826 read-only or read-write (default).
4828 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave``
4829 Creates a memory backend object, which can be used to back the
4830 guest RAM. Memory backend objects offer more control than the
4831 ``-m`` option that is traditionally used to define guest RAM.
4832 Please refer to ``memory-backend-file`` for a description of the
4835 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size``
4836 Creates an anonymous memory file backend object, which allows
4837 QEMU to share the memory with an external process (e.g. when
4838 using vhost-user). The memory is allocated with memfd and
4839 optional sealing. (Linux only)
4841 The ``seal`` option creates a sealed-file, that will block
4842 further resizing the memory ('on' by default).
4844 The ``hugetlb`` option specify the file to be created resides in
4845 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction
4846 with the ``hugetlb`` option, the ``hugetlbsize`` option specify
4847 the hugetlb page size on systems that support multiple hugetlb
4848 page sizes (it must be a power of 2 value supported by the
4851 In some versions of Linux, the ``hugetlb`` option is
4852 incompatible with the ``seal`` option (requires at least Linux
4855 Please refer to ``memory-backend-file`` for a description of the
4858 The ``share`` boolean option is on by default with memfd.
4860 ``-object rng-builtin,id=id``
4861 Creates a random number generator backend which obtains entropy
4862 from QEMU builtin functions. The ``id`` parameter is a unique ID
4863 that will be used to reference this entropy backend from the
4864 ``virtio-rng`` device. By default, the ``virtio-rng`` device
4865 uses this RNG backend.
4867 ``-object rng-random,id=id,filename=/dev/random``
4868 Creates a random number generator backend which obtains entropy
4869 from a device on the host. The ``id`` parameter is a unique ID
4870 that will be used to reference this entropy backend from the
4871 ``virtio-rng`` device. The ``filename`` parameter specifies
4872 which file to obtain entropy from and if omitted defaults to
4875 ``-object rng-egd,id=id,chardev=chardevid``
4876 Creates a random number generator backend which obtains entropy
4877 from an external daemon running on the host. The ``id``
4878 parameter is a unique ID that will be used to reference this
4879 entropy backend from the ``virtio-rng`` device. The ``chardev``
4880 parameter is the unique ID of a character device backend that
4881 provides the connection to the RNG daemon.
4883 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off``
4884 Creates a TLS anonymous credentials object, which can be used to
4885 provide TLS support on network backends. The ``id`` parameter is
4886 a unique ID which network backends will use to access the
4887 credentials. The ``endpoint`` is either ``server`` or ``client``
4888 depending on whether the QEMU network backend that uses the
4889 credentials will be acting as a client or as a server. If
4890 ``verify-peer`` is enabled (the default) then once the handshake
4891 is completed, the peer credentials will be verified, though this
4892 is a no-op for anonymous credentials.
4894 The dir parameter tells QEMU where to find the credential files.
4895 For server endpoints, this directory may contain a file
4896 dh-params.pem providing diffie-hellman parameters to use for the
4897 TLS server. If the file is missing, QEMU will generate a set of
4898 DH parameters at startup. This is a computationally expensive
4899 operation that consumes random pool entropy, so it is
4900 recommended that a persistent set of parameters be generated
4903 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]``
4904 Creates a TLS Pre-Shared Keys (PSK) credentials object, which
4905 can be used to provide TLS support on network backends. The
4906 ``id`` parameter is a unique ID which network backends will use
4907 to access the credentials. The ``endpoint`` is either ``server``
4908 or ``client`` depending on whether the QEMU network backend that
4909 uses the credentials will be acting as a client or as a server.
4910 For clients only, ``username`` is the username which will be
4911 sent to the server. If omitted it defaults to "qemu".
4913 The dir parameter tells QEMU where to find the keys file. It is
4914 called "dir/keys.psk" and contains "username:key" pairs. This
4915 file can most easily be created using the GnuTLS ``psktool``
4918 For server endpoints, dir may also contain a file dh-params.pem
4919 providing diffie-hellman parameters to use for the TLS server.
4920 If the file is missing, QEMU will generate a set of DH
4921 parameters at startup. This is a computationally expensive
4922 operation that consumes random pool entropy, so it is
4923 recommended that a persistent set of parameters be generated up
4926 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id``
4927 Creates a TLS anonymous credentials object, which can be used to
4928 provide TLS support on network backends. The ``id`` parameter is
4929 a unique ID which network backends will use to access the
4930 credentials. The ``endpoint`` is either ``server`` or ``client``
4931 depending on whether the QEMU network backend that uses the
4932 credentials will be acting as a client or as a server. If
4933 ``verify-peer`` is enabled (the default) then once the handshake
4934 is completed, the peer credentials will be verified. With x509
4935 certificates, this implies that the clients must be provided
4936 with valid client certificates too.
4938 The dir parameter tells QEMU where to find the credential files.
4939 For server endpoints, this directory may contain a file
4940 dh-params.pem providing diffie-hellman parameters to use for the
4941 TLS server. If the file is missing, QEMU will generate a set of
4942 DH parameters at startup. This is a computationally expensive
4943 operation that consumes random pool entropy, so it is
4944 recommended that a persistent set of parameters be generated
4947 For x509 certificate credentials the directory will contain
4948 further files providing the x509 certificates. The certificates
4949 must be stored in PEM format, in filenames ca-cert.pem,
4950 ca-crl.pem (optional), server-cert.pem (only servers),
4951 server-key.pem (only servers), client-cert.pem (only clients),
4952 and client-key.pem (only clients).
4954 For the server-key.pem and client-key.pem files which contain
4955 sensitive private keys, it is possible to use an encrypted
4956 version by providing the passwordid parameter. This provides the
4957 ID of a previously created ``secret`` object containing the
4958 password for decryption.
4960 The priority parameter allows to override the global default
4961 priority used by gnutls. This can be useful if the system
4962 administrator needs to use a weaker set of crypto priorities for
4963 QEMU without potentially forcing the weakness onto all
4964 applications. Or conversely if one wants wants a stronger
4965 default for QEMU than for all other applications, they can do
4966 this through this parameter. Its format is a gnutls priority
4967 string as described at
4968 https://gnutls.org/manual/html_node/Priority-Strings.html.
4970 ``-object tls-cipher-suites,id=id,priority=priority``
4971 Creates a TLS cipher suites object, which can be used to control
4972 the TLS cipher/protocol algorithms that applications are permitted
4975 The ``id`` parameter is a unique ID which frontends will use to
4976 access the ordered list of permitted TLS cipher suites from the
4979 The ``priority`` parameter allows to override the global default
4980 priority used by gnutls. This can be useful if the system
4981 administrator needs to use a weaker set of crypto priorities for
4982 QEMU without potentially forcing the weakness onto all
4983 applications. Or conversely if one wants wants a stronger
4984 default for QEMU than for all other applications, they can do
4985 this through this parameter. Its format is a gnutls priority
4986 string as described at
4987 https://gnutls.org/manual/html_node/Priority-Strings.html.
4989 An example of use of this object is to control UEFI HTTPS Boot.
4990 The tls-cipher-suites object exposes the ordered list of permitted
4991 TLS cipher suites from the host side to the guest firmware, via
4992 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER
4993 objects. The firmware uses the IANA_TLS_CIPHER array for configuring
4996 In the following example, the priority at which the host-side policy
4997 is retrieved is given by the ``priority`` property.
4998 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to
4999 refer to /etc/crypto-policies/back-ends/gnutls.config.
5004 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\
5005 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
5007 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
5008 Interval t can't be 0, this filter batches the packet delivery:
5009 all packets arriving in a given interval on netdev netdevid are
5010 delayed until the end of the interval. Interval is in
5011 microseconds. ``status`` is optional that indicate whether the
5012 netfilter is on (enabled) or off (disabled), the default status
5013 for netfilter will be 'on'.
5015 queue all\|rx\|tx is an option that can be applied to any
5018 ``all``: the filter is attached both to the receive and the
5019 transmit queue of the netdev (default).
5021 ``rx``: the filter is attached to the receive queue of the
5022 netdev, where it will receive packets sent to the netdev.
5024 ``tx``: the filter is attached to the transmit queue of the
5025 netdev, where it will receive packets sent by the netdev.
5027 position head\|tail\|id=<id> is an option to specify where the
5028 filter should be inserted in the filter list. It can be applied
5031 ``head``: the filter is inserted at the head of the filter list,
5032 before any existing filters.
5034 ``tail``: the filter is inserted at the tail of the filter list,
5035 behind any existing filters (default).
5037 ``id=<id>``: the filter is inserted before or behind the filter
5038 specified by <id>, see the insert option below.
5040 insert behind\|before is an option to specify where to insert
5041 the new filter relative to the one specified with
5042 position=id=<id>. It can be applied to any netfilter.
5044 ``before``: insert before the specified filter.
5046 ``behind``: insert behind the specified filter (default).
5048 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5049 filter-mirror on netdev netdevid,mirror net packet to
5050 chardevchardevid, if it has the vnet\_hdr\_support flag,
5051 filter-mirror will mirror packet with vnet\_hdr\_len.
5053 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5054 filter-redirector on netdev netdevid,redirect filter's net
5055 packet to chardev chardevid,and redirect indev's packet to
5056 filter.if it has the vnet\_hdr\_support flag, filter-redirector
5057 will redirect packet with vnet\_hdr\_len. Create a
5058 filter-redirector we need to differ outdev id from indev id, id
5059 can not be the same. we can just use indev or outdev, but at
5060 least one of indev or outdev need to be specified.
5062 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
5063 Filter-rewriter is a part of COLO project.It will rewrite tcp
5064 packet to secondary from primary to keep secondary tcp
5065 connection,and rewrite tcp packet to primary from secondary make
5066 tcp packet can be handled by client.if it has the
5067 vnet\_hdr\_support flag, we can parse packet with vnet header.
5069 usage: colo secondary: -object
5070 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object
5071 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object
5072 filter-rewriter,id=rew0,netdev=hn0,queue=all
5074 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]``
5075 Dump the network traffic on netdev dev to the file specified by
5076 filename. At most len bytes (64k by default) per packet are
5077 stored. The file format is libpcap, so it can be analyzed with
5078 tools such as tcpdump or Wireshark.
5080 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]``
5081 Colo-compare gets packet from primary\_in chardevid and
5082 secondary\_in, then compare whether the payload of primary packet
5083 and secondary packet are the same. If same, it will output
5084 primary packet to out\_dev, else it will notify COLO-framework to do
5085 checkpoint and send primary packet to out\_dev. In order to
5086 improve efficiency, we need to put the task of comparison in
5087 another iothread. If it has the vnet\_hdr\_support flag,
5088 colo compare will send/recv packet with vnet\_hdr\_len.
5089 The compare\_timeout=@var{ms} determines the maximum time of the
5090 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms}
5091 is to set the period of scanning expired primary node network packets.
5092 The max\_queue\_size=@var{size} is to set the max compare queue
5093 size depend on user environment.
5094 If user want to use Xen COLO, need to add the notify\_dev to
5095 notify Xen colo-frame to do checkpoint.
5097 COLO-compare must be used with the help of filter-mirror,
5098 filter-redirector and filter-rewriter.
5105 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5106 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5107 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5108 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5109 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5110 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5111 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5112 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5113 -object iothread,id=iothread1
5114 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5115 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5116 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5117 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
5120 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5121 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5122 -chardev socket,id=red0,host=3.3.3.3,port=9003
5123 -chardev socket,id=red1,host=3.3.3.3,port=9004
5124 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5125 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5131 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
5132 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
5133 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off
5134 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off
5135 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off
5136 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
5137 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off
5138 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
5139 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off
5140 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
5141 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
5142 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
5143 -object iothread,id=iothread1
5144 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
5147 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
5148 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
5149 -chardev socket,id=red0,host=3.3.3.3,port=9003
5150 -chardev socket,id=red1,host=3.3.3.3,port=9004
5151 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
5152 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
5154 If you want to know the detail of above command line, you can
5155 read the colo-compare git log.
5157 ``-object cryptodev-backend-builtin,id=id[,queues=queues]``
5158 Creates a cryptodev backend which executes crypto opreation from
5159 the QEMU cipher APIS. The id parameter is a unique ID that will
5160 be used to reference this cryptodev backend from the
5161 ``virtio-crypto`` device. The queues parameter is optional,
5162 which specify the queue number of cryptodev backend, the default
5169 -object cryptodev-backend-builtin,id=cryptodev0 \\
5170 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5173 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]``
5174 Creates a vhost-user cryptodev backend, backed by a chardev
5175 chardevid. The id parameter is a unique ID that will be used to
5176 reference this cryptodev backend from the ``virtio-crypto``
5177 device. The chardev should be a unix domain socket backed one.
5178 The vhost-user uses a specifically defined protocol to pass
5179 vhost ioctl replacement messages to an application on the other
5180 end of the socket. The queues parameter is optional, which
5181 specify the queue number of cryptodev backend for multiqueue
5182 vhost-user, the default of queues is 1.
5188 -chardev socket,id=chardev0,path=/path/to/socket \\
5189 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\
5190 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\
5193 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]``
5195 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]``
5196 Defines a secret to store a password, encryption key, or some
5197 other sensitive data. The sensitive data can either be passed
5198 directly via the data parameter, or indirectly via the file
5199 parameter. Using the data parameter is insecure unless the
5200 sensitive data is encrypted.
5202 The sensitive data can be provided in raw format (the default),
5203 or base64. When encoded as JSON, the raw format only supports
5204 valid UTF-8 characters, so base64 is recommended for sending
5205 binary data. QEMU will convert from which ever format is
5206 provided to the format it needs internally. eg, an RBD password
5207 can be provided in raw format, even though it will be base64
5208 encoded when passed onto the RBD sever.
5210 For added protection, it is possible to encrypt the data
5211 associated with a secret using the AES-256-CBC cipher. Use of
5212 encryption is indicated by providing the keyid and iv
5213 parameters. The keyid parameter provides the ID of a previously
5214 defined secret that contains the AES-256 decryption key. This
5215 key should be 32-bytes long and be base64 encoded. The iv
5216 parameter provides the random initialization vector used for
5217 encryption of this particular secret and should be a base64
5218 encrypted string of the 16-byte IV.
5220 The simplest (insecure) usage is to provide the secret inline
5224 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw
5226 The simplest secure usage is to provide the secret via a file
5228 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object
5229 secret,id=sec0,file=mypasswd.txt,format=raw
5231 For greater security, AES-256-CBC should be used. To illustrate
5232 usage, consider the openssl command line tool which can encrypt
5233 the data. Note that when encrypting, the plaintext must be
5234 padded to the cipher block size (32 bytes) using the standard
5235 PKCS#5/6 compatible padding algorithm.
5237 First a master key needs to be created in base64 encoding:
5241 # openssl rand -base64 32 > key.b64
5242 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
5244 Each secret to be encrypted needs to have a random
5245 initialization vector generated. These do not need to be kept
5250 # openssl rand -base64 16 > iv.b64
5251 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
5253 The secret to be defined can now be encrypted, in this case
5254 we're telling openssl to base64 encode the result, but it could
5255 be left as raw bytes if desired.
5259 # SECRET=$(printf "letmein" |
5260 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
5262 When launching QEMU, create a master secret pointing to
5263 ``key.b64`` and specify that to be used to decrypt the user
5264 password. Pass the contents of ``iv.b64`` to the second secret
5269 -object secret,id=secmaster0,format=base64,file=key.b64 \\
5270 -object secret,id=sec0,keyid=secmaster0,format=base64,\\
5271 data=$SECRET,iv=$(<iv.b64)
5273 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file,kernel-hashes=on|off]``
5274 Create a Secure Encrypted Virtualization (SEV) guest object,
5275 which can be used to provide the guest memory encryption support
5278 When memory encryption is enabled, one of the physical address
5279 bit (aka the C-bit) is utilized to mark if a memory page is
5280 protected. The ``cbitpos`` is used to provide the C-bit
5281 position. The C-bit position is Host family dependent hence user
5282 must provide this value. On EPYC, the value should be 47.
5284 When memory encryption is enabled, we loose certain bits in
5285 physical address space. The ``reduced-phys-bits`` is used to
5286 provide the number of bits we loose in physical address space.
5287 Similar to C-bit, the value is Host family dependent. On EPYC,
5288 the value should be 5.
5290 The ``sev-device`` provides the device file to use for
5291 communicating with the SEV firmware running inside AMD Secure
5292 Processor. The default device is '/dev/sev'. If hardware
5293 supports memory encryption then /dev/sev devices are created by
5296 The ``policy`` provides the guest policy to be enforced by the
5297 SEV firmware and restrict what configuration and operational
5298 commands can be performed on this guest by the hypervisor. The
5299 policy should be provided by the guest owner and is bound to the
5300 guest and cannot be changed throughout the lifetime of the
5301 guest. The default is 0.
5303 If guest ``policy`` allows sharing the key with another SEV
5304 guest then ``handle`` can be use to provide handle of the guest
5305 from which to share the key.
5307 The ``dh-cert-file`` and ``session-file`` provides the guest
5308 owner's Public Diffie-Hillman key defined in SEV spec. The PDH
5309 and session parameters are used for establishing a cryptographic
5310 session with the guest owner to negotiate keys used for
5311 attestation. The file must be encoded in base64.
5313 The ``kernel-hashes`` adds the hashes of given kernel/initrd/
5314 cmdline to a designated guest firmware page for measured Linux
5315 boot with -kernel. The default is off. (Since 6.2)
5317 e.g to launch a SEV guest
5321 # |qemu_system_x86| \\
5323 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\
5324 -machine ...,memory-encryption=sev0 \\
5327 ``-object authz-simple,id=id,identity=string``
5328 Create an authorization object that will control access to
5331 The ``identity`` parameter is identifies the user and its format
5332 depends on the network service that authorization object is
5333 associated with. For authorizing based on TLS x509 certificates,
5334 the identity must be the x509 distinguished name. Note that care
5335 must be taken to escape any commas in the distinguished name.
5337 An example authorization object to validate a x509 distinguished
5338 name would look like:
5344 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\
5347 Note the use of quotes due to the x509 distinguished name
5348 containing whitespace, and escaping of ','.
5350 ``-object authz-listfile,id=id,filename=path,refresh=on|off``
5351 Create an authorization object that will control access to
5354 The ``filename`` parameter is the fully qualified path to a file
5355 containing the access control list rules in JSON format.
5357 An example set of rules that match against SASL usernames might
5364 { "match": "fred", "policy": "allow", "format": "exact" },
5365 { "match": "bob", "policy": "allow", "format": "exact" },
5366 { "match": "danb", "policy": "deny", "format": "glob" },
5367 { "match": "dan*", "policy": "allow", "format": "exact" },
5372 When checking access the object will iterate over all the rules
5373 and the first rule to match will have its ``policy`` value
5374 returned as the result. If no rules match, then the default
5375 ``policy`` value is returned.
5377 The rules can either be an exact string match, or they can use
5378 the simple UNIX glob pattern matching to allow wildcards to be
5381 If ``refresh`` is set to true the file will be monitored and
5382 automatically reloaded whenever its content changes.
5384 As with the ``authz-simple`` object, the format of the identity
5385 strings being matched depends on the network service, but is
5386 usually a TLS x509 distinguished name, or a SASL username.
5388 An example authorization object to validate a SASL username
5395 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\
5398 ``-object authz-pam,id=id,service=string``
5399 Create an authorization object that will control access to
5402 The ``service`` parameter provides the name of a PAM service to
5403 use for authorization. It requires that a file
5404 ``/etc/pam.d/service`` exist to provide the configuration for
5405 the ``account`` subsystem.
5407 An example authorization object to validate a TLS x509
5408 distinguished name would look like:
5414 -object authz-pam,id=auth0,service=qemu-vnc \\
5417 There would then be a corresponding config file for PAM at
5418 ``/etc/pam.d/qemu-vnc`` that contains:
5422 account requisite pam_listfile.so item=user sense=allow \
5423 file=/etc/qemu/vnc.allow
5425 Finally the ``/etc/qemu/vnc.allow`` file would contain the list
5426 of x509 distingished names that are permitted access
5430 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
5432 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch``
5433 Creates a dedicated event loop thread that devices can be
5434 assigned to. This is known as an IOThread. By default device
5435 emulation happens in vCPU threads or the main event loop thread.
5436 This can become a scalability bottleneck. IOThreads allow device
5437 emulation and I/O to run on other host CPUs.
5439 The ``id`` parameter is a unique ID that will be used to
5440 reference this IOThread from ``-device ...,iothread=id``.
5441 Multiple devices can be assigned to an IOThread. Note that not
5442 all devices support an ``iothread`` parameter.
5444 The ``query-iothreads`` QMP command lists IOThreads and reports
5445 their thread IDs so that the user can configure host CPU
5448 IOThreads use an adaptive polling algorithm to reduce event loop
5449 latency. Instead of entering a blocking system call to monitor
5450 file descriptors and then pay the cost of being woken up when an
5451 event occurs, the polling algorithm spins waiting for events for
5452 a short time. The algorithm's default parameters are suitable
5453 for many cases but can be adjusted based on knowledge of the
5454 workload and/or host device latency.
5456 The ``poll-max-ns`` parameter is the maximum number of
5457 nanoseconds to busy wait for events. Polling can be disabled by
5458 setting this value to 0.
5460 The ``poll-grow`` parameter is the multiplier used to increase
5461 the polling time when the algorithm detects it is missing events
5462 due to not polling long enough.
5464 The ``poll-shrink`` parameter is the divisor used to decrease
5465 the polling time when the algorithm detects it is spending too
5466 long polling without encountering events.
5468 The ``aio-max-batch`` parameter is the maximum number of requests
5469 in a batch for the AIO engine, 0 means that the engine will use
5472 The IOThread parameters can be modified at run-time using the
5473 ``qom-set`` command (where ``iothread1`` is the IOThread's
5478 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
5482 HXCOMM This is the last statement. Insert new options before this line!
projects / qemu.git / blob