1 HXCOMM Use DEFHEADING() to define headings in both help text and texi
2 HXCOMM Text between STEXI and ETEXI are copied to texi 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 texi and C
9 DEFHEADING(Standard options:)
14 DEF("help", 0, QEMU_OPTION_h,
15 "-h or -help display this help and exit\n", QEMU_ARCH_ALL)
22 DEF("version", 0, QEMU_OPTION_version,
23 "-version display version information and exit\n", QEMU_ARCH_ALL)
27 Display version information and exit
30 DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
31 "-machine [type=]name[,prop[=value][,...]]\n"
32 " selects emulated machine ('-machine help' for list)\n"
33 " property accel=accel1[:accel2[:...]] selects accelerator\n"
34 " supported accelerators are kvm, xen, hax, hvf, whpx or tcg (default: tcg)\n"
35 " vmport=on|off|auto controls emulation of vmport (default: auto)\n"
36 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
37 " mem-merge=on|off controls memory merge support (default: on)\n"
38 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
39 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
40 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
41 " nvdimm=on|off controls NVDIMM support (default=off)\n"
42 " enforce-config-section=on|off enforce configuration section migration (default=off)\n"
43 " memory-encryption=@var{} memory encryption object to use (default=none)\n"
44 " hmat=on|off controls ACPI HMAT support (default=off)\n",
47 @item -machine [type=]@var{name}[,prop=@var{value}[,...]]
49 Select the emulated machine by @var{name}. Use @code{-machine help} to list
52 For architectures which aim to support live migration compatibility
53 across releases, each release will introduce a new versioned machine
54 type. For example, the 2.8.0 release introduced machine types
55 ``pc-i440fx-2.8'' and ``pc-q35-2.8'' for the x86_64/i686 architectures.
57 To allow live migration of guests from QEMU version 2.8.0, to QEMU
58 version 2.9.0, the 2.9.0 version must support the ``pc-i440fx-2.8''
59 and ``pc-q35-2.8'' machines too. To allow users live migrating VMs
60 to skip multiple intermediate releases when upgrading, new releases
61 of QEMU will support machine types from many previous versions.
63 Supported machine properties are:
65 @item accel=@var{accels1}[:@var{accels2}[:...]]
66 This is used to enable an accelerator. Depending on the target architecture,
67 kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is
68 more than one accelerator specified, the next one is used if the previous one
70 @item vmport=on|off|auto
71 Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the
72 value based on accel. For accel=xen the default is off otherwise the default
74 @item dump-guest-core=on|off
75 Include guest memory in a core dump. The default is on.
76 @item mem-merge=on|off
77 Enables or disables memory merge support. This feature, when supported by
78 the host, de-duplicates identical memory pages among VMs instances
80 @item aes-key-wrap=on|off
81 Enables or disables AES key wrapping support on s390-ccw hosts. This feature
82 controls whether AES wrapping keys will be created to allow
83 execution of AES cryptographic functions. The default is on.
84 @item dea-key-wrap=on|off
85 Enables or disables DEA key wrapping support on s390-ccw hosts. This feature
86 controls whether DEA wrapping keys will be created to allow
87 execution of DEA cryptographic functions. The default is on.
89 Enables or disables NVDIMM support. The default is off.
90 @item enforce-config-section=on|off
91 If @option{enforce-config-section} is set to @var{on}, force migration
92 code to send configuration section even if the machine-type sets the
93 @option{migration.send-configuration} property to @var{off}.
94 NOTE: this parameter is deprecated. Please use @option{-global}
95 @option{migration.send-configuration}=@var{on|off} instead.
96 @item memory-encryption=@var{}
97 Memory encryption object to use. The default is none.
99 Enables or disables ACPI Heterogeneous Memory Attribute Table (HMAT) support.
104 HXCOMM Deprecated by -machine
105 DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL)
107 DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
108 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
110 @item -cpu @var{model}
112 Select CPU model (@code{-cpu help} for list and additional feature selection)
115 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
116 "-accel [accel=]accelerator[,prop[=value][,...]]\n"
117 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n"
118 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
119 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n"
120 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n"
121 " tb-size=n (TCG translation block cache size)\n"
122 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
124 @item -accel @var{name}[,prop=@var{value}[,...]]
126 This is used to enable an accelerator. Depending on the target architecture,
127 kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is
128 more than one accelerator specified, the next one is used if the previous one
131 @item igd-passthru=on|off
132 When Xen is in use, this option controls whether Intel integrated graphics
133 devices can be passed through to the guest (default=off)
134 @item kernel-irqchip=on|off|split
135 Controls KVM in-kernel irqchip support. The default is full acceleration of the
136 interrupt controllers. On x86, split irqchip reduces the kernel attack
137 surface, at a performance cost for non-MSI interrupts. Disabling the in-kernel
138 irqchip completely is not recommended except for debugging purposes.
139 @item kvm-shadow-mem=size
140 Defines the size of the KVM shadow MMU.
141 @item tb-size=@var{n}
142 Controls the size (in MiB) of the TCG translation block cache.
143 @item thread=single|multi
144 Controls number of TCG threads. When the TCG is multi-threaded there will be one
145 thread per vCPU therefor taking advantage of additional host cores. The default
146 is to enable multi-threading where both the back-end and front-ends support it and
147 no incompatible TCG features have been enabled (e.g. icount/replay).
151 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
152 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
153 " set the number of CPUs to 'n' [default=1]\n"
154 " maxcpus= maximum number of total cpus, including\n"
155 " offline CPUs for hotplug, etc\n"
156 " cores= number of CPU cores on one socket (for PC, it's on one die)\n"
157 " threads= number of threads on one CPU core\n"
158 " dies= number of CPU dies on one socket (for PC only)\n"
159 " sockets= number of discrete sockets in the system\n",
162 @item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,dies=dies][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
164 Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
165 CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
167 For the PC target, the number of @var{cores} per die, the number of @var{threads}
168 per cores, the number of @var{dies} per packages and the total number of
169 @var{sockets} can be specified. Missing values will be computed.
170 If any on the three values is given, the total number of CPUs @var{n} can be omitted.
171 @var{maxcpus} specifies the maximum number of hotpluggable CPUs.
174 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
175 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
176 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n"
177 "-numa dist,src=source,dst=destination,val=distance\n"
178 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n"
179 "-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",
182 @item -numa node[,mem=@var{size}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}][,initiator=@var{initiator}]
183 @itemx -numa node[,memdev=@var{id}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}][,initiator=@var{initiator}]
184 @itemx -numa dist,src=@var{source},dst=@var{destination},val=@var{distance}
185 @itemx -numa cpu,node-id=@var{node}[,socket-id=@var{x}][,core-id=@var{y}][,thread-id=@var{z}]
186 @itemx -numa hmat-lb,initiator=@var{node},target=@var{node},hierarchy=@var{hierarchy},data-type=@var{tpye}[,latency=@var{lat}][,bandwidth=@var{bw}]
188 Define a NUMA node and assign RAM and VCPUs to it.
189 Set the NUMA distance from a source node to a destination node.
190 Set the ACPI Heterogeneous Memory Attributes for the given nodes.
192 Legacy VCPU assignment uses @samp{cpus} option where
193 @var{firstcpu} and @var{lastcpu} are CPU indexes. Each
194 @samp{cpus} option represent a contiguous range of CPU indexes
195 (or a single VCPU if @var{lastcpu} is omitted). A non-contiguous
196 set of VCPUs can be represented by providing multiple @samp{cpus}
197 options. If @samp{cpus} is omitted on all nodes, VCPUs are automatically
200 For example, the following option assigns VCPUs 0, 1, 2 and 5 to
203 -numa node,cpus=0-2,cpus=5
206 @samp{cpu} option is a new alternative to @samp{cpus} option
207 which uses @samp{socket-id|core-id|thread-id} properties to assign
208 CPU objects to a @var{node} using topology layout properties of CPU.
209 The set of properties is machine specific, and depends on used
210 machine type/@samp{smp} options. It could be queried with
211 @samp{hotpluggable-cpus} monitor command.
212 @samp{node-id} property specifies @var{node} to which CPU object
213 will be assigned, it's required for @var{node} to be declared
214 with @samp{node} option before it's used with @samp{cpu} option.
219 -smp 1,sockets=2,maxcpus=2 \
220 -numa node,nodeid=0 -numa node,nodeid=1 \
221 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
224 @samp{mem} assigns a given RAM amount to a node. @samp{memdev}
225 assigns RAM from a given memory backend device to a node. If
226 @samp{mem} and @samp{memdev} are omitted in all nodes, RAM is
227 split equally between them.
229 @samp{mem} and @samp{memdev} are mutually exclusive. Furthermore,
230 if one node uses @samp{memdev}, all of them have to use it.
232 @samp{initiator} is an additional option that points to an @var{initiator}
233 NUMA node that has best performance (the lowest latency or largest bandwidth)
234 to this NUMA @var{node}. Note that this option can be set only when
235 the machine property 'hmat' is set to 'on'.
237 Following example creates a machine with 2 NUMA nodes, node 0 has CPU.
238 node 1 has only memory, and its initiator is node 0. Note that because
239 node 0 has CPU, by default the initiator of node 0 is itself and must be
243 -m 2G,slots=2,maxmem=4G \
244 -object memory-backend-ram,size=1G,id=m0 \
245 -object memory-backend-ram,size=1G,id=m1 \
246 -numa node,nodeid=0,memdev=m0 \
247 -numa node,nodeid=1,memdev=m1,initiator=0 \
248 -smp 2,sockets=2,maxcpus=2 \
249 -numa cpu,node-id=0,socket-id=0 \
250 -numa cpu,node-id=0,socket-id=1
253 @var{source} and @var{destination} are NUMA node IDs.
254 @var{distance} is the NUMA distance from @var{source} to @var{destination}.
255 The distance from a node to itself is always 10. If any pair of nodes is
256 given a distance, then all pairs must be given distances. Although, when
257 distances are only given in one direction for each pair of nodes, then
258 the distances in the opposite directions are assumed to be the same. If,
259 however, an asymmetrical pair of distances is given for even one node
260 pair, then all node pairs must be provided distance values for both
261 directions, even when they are symmetrical. When a node is unreachable
262 from another node, set the pair's distance to 255.
264 Note that the -@option{numa} option doesn't allocate any of the
265 specified resources, it just assigns existing resources to NUMA
266 nodes. This means that one still has to use the @option{-m},
267 @option{-smp} options to allocate RAM and VCPUs respectively.
269 Use @samp{hmat-lb} to set System Locality Latency and Bandwidth Information
270 between initiator and target NUMA nodes in ACPI Heterogeneous Attribute Memory Table (HMAT).
271 Initiator NUMA node can create memory requests, usually it has one or more processors.
272 Target NUMA node contains addressable memory.
274 In @samp{hmat-lb} option, @var{node} are NUMA node IDs. @var{hierarchy} is the memory
275 hierarchy of the target NUMA node: if @var{hierarchy} is 'memory', the structure
276 represents the memory performance; if @var{hierarchy} is 'first-level|second-level|third-level',
277 this structure represents aggregated performance of memory side caches for each domain.
278 @var{type} of 'data-type' is type of data represented by this structure instance:
279 if 'hierarchy' is 'memory', 'data-type' is 'access|read|write' latency or 'access|read|write'
280 bandwidth of the target memory; if 'hierarchy' is 'first-level|second-level|third-level',
281 'data-type' is 'access|read|write' hit latency or 'access|read|write' hit bandwidth of the
282 target memory side cache.
284 @var{lat} is latency value in nanoseconds. @var{bw} is bandwidth value,
285 the possible value and units are NUM[M|G|T], mean that the bandwidth value are
286 NUM byte per second (or MB/s, GB/s or TB/s depending on used suffix).
287 Note that if latency or bandwidth value is 0, means the corresponding latency or
288 bandwidth information is not provided.
290 For example, the following options describe 2 NUMA nodes. Node 0 has 2 cpus and
291 a ram, node 1 has only a ram. The processors in node 0 access memory in node
292 0 with access-latency 5 nanoseconds, access-bandwidth is 200 MB/s;
293 The processors in NUMA node 0 access memory in NUMA node 1 with access-latency 10
294 nanoseconds, access-bandwidth is 100 MB/s.
298 -object memory-backend-ram,size=1G,id=m0 \
299 -object memory-backend-ram,size=1G,id=m1 \
301 -numa node,nodeid=0,memdev=m0 \
302 -numa node,nodeid=1,memdev=m1,initiator=0 \
303 -numa cpu,node-id=0,socket-id=0 \
304 -numa cpu,node-id=0,socket-id=1 \
305 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \
306 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \
307 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \
308 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M
313 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
314 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
315 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
317 @item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}]
320 Add a file descriptor to an fd set. Valid options are:
324 This option defines the file descriptor of which a duplicate is added to fd set.
325 The file descriptor cannot be stdin, stdout, or stderr.
327 This option defines the ID of the fd set to add the file descriptor to.
328 @item opaque=@var{opaque}
329 This option defines a free-form string that can be used to describe @var{fd}.
332 You can open an image using pre-opened file descriptors from an fd set:
334 @value{qemu_system} \
335 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \
336 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \
337 -drive file=/dev/fdset/2,index=0,media=disk
341 DEF("set", HAS_ARG, QEMU_OPTION_set,
342 "-set group.id.arg=value\n"
343 " set <arg> parameter for item <id> of type <group>\n"
344 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
346 @item -set @var{group}.@var{id}.@var{arg}=@var{value}
348 Set parameter @var{arg} for item @var{id} of type @var{group}
351 DEF("global", HAS_ARG, QEMU_OPTION_global,
352 "-global driver.property=value\n"
353 "-global driver=driver,property=property,value=value\n"
354 " set a global default for a driver property\n",
357 @item -global @var{driver}.@var{prop}=@var{value}
358 @itemx -global driver=@var{driver},property=@var{property},value=@var{value}
360 Set default value of @var{driver}'s property @var{prop} to @var{value}, e.g.:
363 @value{qemu_system_x86} -global ide-hd.physical_block_size=4096 disk-image.img
366 In particular, you can use this to set driver properties for devices which are
367 created automatically by the machine model. To create a device which is not
368 created automatically and set properties on it, use -@option{device}.
370 -global @var{driver}.@var{prop}=@var{value} is shorthand for -global
371 driver=@var{driver},property=@var{prop},value=@var{value}. The
372 longhand syntax works even when @var{driver} contains a dot.
375 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
376 "-boot [order=drives][,once=drives][,menu=on|off]\n"
377 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
378 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
379 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
380 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
381 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
384 @item -boot [order=@var{drives}][,once=@var{drives}][,menu=on|off][,splash=@var{sp_name}][,splash-time=@var{sp_time}][,reboot-timeout=@var{rb_timeout}][,strict=on|off]
386 Specify boot order @var{drives} as a string of drive letters. Valid
387 drive letters depend on the target architecture. The x86 PC uses: a, b
388 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
389 from network adapter 1-4), hard disk boot is the default. To apply a
390 particular boot order only on the first startup, specify it via
391 @option{once}. Note that the @option{order} or @option{once} parameter
392 should not be used together with the @option{bootindex} property of
393 devices, since the firmware implementations normally do not support both
396 Interactive boot menus/prompts can be enabled via @option{menu=on} as far
397 as firmware/BIOS supports them. The default is non-interactive boot.
399 A splash picture could be passed to bios, enabling user to show it as logo,
400 when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
401 supports them. Currently Seabios for X86 system support it.
402 limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
403 format(true color). The resolution should be supported by the SVGA mode, so
404 the recommended is 320x240, 640x480, 800x640.
406 A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
407 when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
408 reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
411 Do strict boot via @option{strict=on} as far as firmware/BIOS
412 supports it. This only effects when boot priority is changed by
413 bootindex options. The default is non-strict boot.
416 # try to boot from network first, then from hard disk
417 @value{qemu_system_x86} -boot order=nc
418 # boot from CD-ROM first, switch back to default order after reboot
419 @value{qemu_system_x86} -boot once=d
420 # boot with a splash picture for 5 seconds.
421 @value{qemu_system_x86} -boot menu=on,splash=/root/boot.bmp,splash-time=5000
424 Note: The legacy format '-boot @var{drives}' is still supported but its
425 use is discouraged as it may be removed from future versions.
428 DEF("m", HAS_ARG, QEMU_OPTION_m,
429 "-m [size=]megs[,slots=n,maxmem=size]\n"
430 " configure guest RAM\n"
431 " size: initial amount of guest memory\n"
432 " slots: number of hotplug slots (default: none)\n"
433 " maxmem: maximum amount of guest memory (default: none)\n"
434 "NOTE: Some architectures might enforce a specific granularity\n",
437 @item -m [size=]@var{megs}[,slots=n,maxmem=size]
439 Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB.
440 Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in
441 megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem}
442 could be used to set amount of hotpluggable memory slots and maximum amount of
443 memory. Note that @var{maxmem} must be aligned to the page size.
445 For example, the following command-line sets the guest startup RAM size to
446 1GB, creates 3 slots to hotplug additional memory and sets the maximum
447 memory the guest can reach to 4GB:
450 @value{qemu_system} -m 1G,slots=3,maxmem=4G
453 If @var{slots} and @var{maxmem} are not specified, memory hotplug won't
454 be enabled and the guest startup RAM will never increase.
457 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
458 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
460 @item -mem-path @var{path}
462 Allocate guest RAM from a temporarily created file in @var{path}.
465 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
466 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
470 @findex -mem-prealloc
471 Preallocate memory when using -mem-path.
474 DEF("k", HAS_ARG, QEMU_OPTION_k,
475 "-k language use keyboard layout (for example 'fr' for French)\n",
478 @item -k @var{language}
480 Use keyboard layout @var{language} (for example @code{fr} for
481 French). This option is only needed where it is not easy to get raw PC
482 keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
483 display). You don't normally need to use it on PC/Linux or PC/Windows
486 The available layouts are:
488 ar de-ch es fo fr-ca hu ja mk no pt-br sv
489 da en-gb et fr fr-ch is lt nl pl ru th
490 de en-us fi fr-be hr it lv nl-be pt sl tr
493 The default is @code{en-us}.
497 HXCOMM Deprecated by -audiodev
498 DEF("audio-help", 0, QEMU_OPTION_audio_help,
499 "-audio-help show -audiodev equivalent of the currently specified audio settings\n",
504 Will show the -audiodev equivalent of the currently specified
505 (deprecated) environment variables.
508 DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
509 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
510 " specifies the audio backend to use\n"
511 " id= identifier of the backend\n"
512 " timer-period= timer period in microseconds\n"
513 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n"
514 " in|out.fixed-settings= use fixed settings for host audio\n"
515 " in|out.frequency= frequency to use with fixed settings\n"
516 " in|out.channels= number of channels to use with fixed settings\n"
517 " in|out.format= sample format to use with fixed settings\n"
518 " valid values: s8, s16, s32, u8, u16, u32\n"
519 " in|out.voices= number of voices to use\n"
520 " in|out.buffer-length= length of buffer in microseconds\n"
521 "-audiodev none,id=id,[,prop[=value][,...]]\n"
522 " dummy driver that discards all output\n"
523 #ifdef CONFIG_AUDIO_ALSA
524 "-audiodev alsa,id=id[,prop[=value][,...]]\n"
525 " in|out.dev= name of the audio device to use\n"
526 " in|out.period-length= length of period in microseconds\n"
527 " in|out.try-poll= attempt to use poll mode\n"
528 " threshold= threshold (in microseconds) when playback starts\n"
530 #ifdef CONFIG_AUDIO_COREAUDIO
531 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
532 " in|out.buffer-count= number of buffers\n"
534 #ifdef CONFIG_AUDIO_DSOUND
535 "-audiodev dsound,id=id[,prop[=value][,...]]\n"
536 " latency= add extra latency to playback in microseconds\n"
538 #ifdef CONFIG_AUDIO_OSS
539 "-audiodev oss,id=id[,prop[=value][,...]]\n"
540 " in|out.dev= path of the audio device to use\n"
541 " in|out.buffer-count= number of buffers\n"
542 " in|out.try-poll= attempt to use poll mode\n"
543 " try-mmap= try using memory mapped access\n"
544 " exclusive= open device in exclusive mode\n"
545 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
547 #ifdef CONFIG_AUDIO_PA
548 "-audiodev pa,id=id[,prop[=value][,...]]\n"
549 " server= PulseAudio server address\n"
550 " in|out.name= source/sink device name\n"
551 " in|out.latency= desired latency in microseconds\n"
553 #ifdef CONFIG_AUDIO_SDL
554 "-audiodev sdl,id=id[,prop[=value][,...]]\n"
557 "-audiodev spice,id=id[,prop[=value][,...]]\n"
559 "-audiodev wav,id=id[,prop[=value][,...]]\n"
560 " path= path of wav file to record\n",
563 @item -audiodev [driver=]@var{driver},id=@var{id}[,@var{prop}[=@var{value}][,...]]
565 Adds a new audio backend @var{driver} identified by @var{id}. There are
566 global and driver specific properties. Some values can be set
567 differently for input and output, they're marked with @code{in|out.}.
568 You can set the input's property with @code{in.@var{prop}} and the
569 output's property with @code{out.@var{prop}}. For example:
571 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
572 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
575 NOTE: parameter validation is known to be incomplete, in many cases
576 specifying an invalid option causes QEMU to print an error message and
577 continue emulation without sound.
579 Valid global options are:
582 @item id=@var{identifier}
583 Identifies the audio backend.
585 @item timer-period=@var{period}
586 Sets the timer @var{period} used by the audio subsystem in microseconds.
587 Default is 10000 (10 ms).
589 @item in|out.mixing-engine=on|off
590 Use QEMU's mixing engine to mix all streams inside QEMU and convert
591 audio formats when not supported by the backend. When off,
592 @var{fixed-settings} must be off too. Note that disabling this option
593 means that the selected backend must support multiple streams and the
594 audio formats used by the virtual cards, otherwise you'll get no sound.
595 It's not recommended to disable this option unless you want to use 5.1
596 or 7.1 audio, as mixing engine only supports mono and stereo audio.
599 @item in|out.fixed-settings=on|off
600 Use fixed settings for host audio. When off, it will change based on
601 how the guest opens the sound card. In this case you must not specify
602 @var{frequency}, @var{channels} or @var{format}. Default is on.
604 @item in|out.frequency=@var{frequency}
605 Specify the @var{frequency} to use when using @var{fixed-settings}.
608 @item in|out.channels=@var{channels}
609 Specify the number of @var{channels} to use when using
610 @var{fixed-settings}. Default is 2 (stereo).
612 @item in|out.format=@var{format}
613 Specify the sample @var{format} to use when using @var{fixed-settings}.
614 Valid values are: @code{s8}, @code{s16}, @code{s32}, @code{u8},
615 @code{u16}, @code{u32}. Default is @code{s16}.
617 @item in|out.voices=@var{voices}
618 Specify the number of @var{voices} to use. Default is 1.
620 @item in|out.buffer-length=@var{usecs}
621 Sets the size of the buffer in microseconds.
625 @item -audiodev none,id=@var{id}[,@var{prop}[=@var{value}][,...]]
626 Creates a dummy backend that discards all outputs. This backend has no
627 backend specific properties.
629 @item -audiodev alsa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
630 Creates backend using the ALSA. This backend is only available on
633 ALSA specific options are:
637 @item in|out.dev=@var{device}
638 Specify the ALSA @var{device} to use for input and/or output. Default
641 @item in|out.period-length=@var{usecs}
642 Sets the period length in microseconds.
644 @item in|out.try-poll=on|off
645 Attempt to use poll mode with the device. Default is on.
647 @item threshold=@var{threshold}
648 Threshold (in microseconds) when playback starts. Default is 0.
652 @item -audiodev coreaudio,id=@var{id}[,@var{prop}[=@var{value}][,...]]
653 Creates a backend using Apple's Core Audio. This backend is only
654 available on Mac OS and only supports playback.
656 Core Audio specific options are:
660 @item in|out.buffer-count=@var{count}
661 Sets the @var{count} of the buffers.
665 @item -audiodev dsound,id=@var{id}[,@var{prop}[=@var{value}][,...]]
666 Creates a backend using Microsoft's DirectSound. This backend is only
667 available on Windows and only supports playback.
669 DirectSound specific options are:
673 @item latency=@var{usecs}
674 Add extra @var{usecs} microseconds latency to playback. Default is
679 @item -audiodev oss,id=@var{id}[,@var{prop}[=@var{value}][,...]]
680 Creates a backend using OSS. This backend is available on most
683 OSS specific options are:
687 @item in|out.dev=@var{device}
688 Specify the file name of the OSS @var{device} to use. Default is
691 @item in|out.buffer-count=@var{count}
692 Sets the @var{count} of the buffers.
694 @item in|out.try-poll=on|of
695 Attempt to use poll mode with the device. Default is on.
697 @item try-mmap=on|off
698 Try using memory mapped device access. Default is off.
700 @item exclusive=on|off
701 Open the device in exclusive mode (vmix won't work in this case).
704 @item dsp-policy=@var{policy}
705 Sets the timing policy (between 0 and 10, where smaller number means
706 smaller latency but higher CPU usage). Use -1 to use buffer sizes
707 specified by @code{buffer} and @code{buffer-count}. This option is
708 ignored if you do not have OSS 4. Default is 5.
712 @item -audiodev pa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
713 Creates a backend using PulseAudio. This backend is available on most
716 PulseAudio specific options are:
720 @item server=@var{server}
721 Sets the PulseAudio @var{server} to connect to.
723 @item in|out.name=@var{sink}
724 Use the specified source/sink for recording/playback.
726 @item in|out.latency=@var{usecs}
727 Desired latency in microseconds. The PulseAudio server will try to honor this
728 value but actual latencies may be lower or higher.
732 @item -audiodev sdl,id=@var{id}[,@var{prop}[=@var{value}][,...]]
733 Creates a backend using SDL. This backend is available on most systems,
734 but you should use your platform's native backend if possible. This
735 backend has no backend specific properties.
737 @item -audiodev spice,id=@var{id}[,@var{prop}[=@var{value}][,...]]
738 Creates a backend that sends audio through SPICE. This backend requires
739 @code{-spice} and automatically selected in that case, so usually you
740 can ignore this option. This backend has no backend specific
743 @item -audiodev wav,id=@var{id}[,@var{prop}[=@var{value}][,...]]
744 Creates a backend that writes audio to a WAV file.
746 Backend specific options are:
750 @item path=@var{path}
751 Write recorded audio into the specified file. Default is
757 DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
758 "-soundhw c1,... enable audio support\n"
759 " and only specified sound cards (comma separated list)\n"
760 " use '-soundhw help' to get the list of supported cards\n"
761 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
763 @item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
765 Enable audio and selected sound hardware. Use 'help' to print all
766 available sound hardware. For example:
769 @value{qemu_system_x86} -soundhw sb16,adlib disk.img
770 @value{qemu_system_x86} -soundhw es1370 disk.img
771 @value{qemu_system_x86} -soundhw ac97 disk.img
772 @value{qemu_system_x86} -soundhw hda disk.img
773 @value{qemu_system_x86} -soundhw all disk.img
774 @value{qemu_system_x86} -soundhw help
777 Note that Linux's i810_audio OSS kernel (for AC97) module might
778 require manually specifying clocking.
781 modprobe i810_audio clocking=48000
785 DEF("device", HAS_ARG, QEMU_OPTION_device,
786 "-device driver[,prop[=value][,...]]\n"
787 " add device (based on driver)\n"
788 " prop=value,... sets driver properties\n"
789 " use '-device help' to print all possible drivers\n"
790 " use '-device driver,help' to print all possible properties\n",
793 @item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
795 Add device @var{driver}. @var{prop}=@var{value} sets driver
796 properties. Valid properties depend on the driver. To get help on
797 possible drivers and properties, use @code{-device help} and
798 @code{-device @var{driver},help}.
801 @item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}][,guid=@var{uuid}]
803 Add an IPMI BMC. This is a simulation of a hardware management
804 interface processor that normally sits on a system. It provides
805 a watchdog and the ability to reset and power control the system.
806 You need to connect this to an IPMI interface to make it useful
808 The IPMI slave address to use for the BMC. The default is 0x20.
809 This address is the BMC's address on the I2C network of management
810 controllers. If you don't know what this means, it is safe to ignore
815 The BMC id for interfaces to use this device.
816 @item slave_addr=@var{val}
817 Define slave address to use for the BMC. The default is 0x20.
818 @item sdrfile=@var{file}
819 file containing raw Sensor Data Records (SDR) data. The default is none.
820 @item fruareasize=@var{val}
821 size of a Field Replaceable Unit (FRU) area. The default is 1024.
822 @item frudatafile=@var{file}
823 file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
824 @item guid=@var{uuid}
825 value for the GUID for the BMC, in standard UUID format. If this is set,
826 get "Get GUID" command to the BMC will return it. Otherwise "Get GUID"
827 will return an error.
830 @item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
832 Add a connection to an external IPMI BMC simulator. Instead of
833 locally emulating the BMC like the above item, instead connect
834 to an external entity that provides the IPMI services.
836 A connection is made to an external BMC simulator. If you do this, it
837 is strongly recommended that you use the "reconnect=" chardev option
838 to reconnect to the simulator if the connection is lost. Note that if
839 this is not used carefully, it can be a security issue, as the
840 interface has the ability to send resets, NMIs, and power off the VM.
841 It's best if QEMU makes a connection to an external simulator running
842 on a secure port on localhost, so neither the simulator nor QEMU is
843 exposed to any outside network.
845 See the "lanserv/README.vm" file in the OpenIPMI library for more
846 details on the external interface.
848 @item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
850 Add a KCS IPMI interafce on the ISA bus. This also adds a
851 corresponding ACPI and SMBIOS entries, if appropriate.
855 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
856 @item ioport=@var{val}
857 Define the I/O address of the interface. The default is 0xca0 for KCS.
859 Define the interrupt to use. The default is 5. To disable interrupts,
863 @item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
865 Like the KCS interface, but defines a BT interface. The default port is
866 0xe4 and the default interrupt is 5.
870 DEF("name", HAS_ARG, QEMU_OPTION_name,
871 "-name string1[,process=string2][,debug-threads=on|off]\n"
872 " set the name of the guest\n"
873 " string1 sets the window title and string2 the process name\n"
874 " When debug-threads is enabled, individual threads are given a separate name\n"
875 " NOTE: The thread names are for debugging and not a stable API.\n",
878 @item -name @var{name}
880 Sets the @var{name} of the guest.
881 This name will be displayed in the SDL window caption.
882 The @var{name} will also be used for the VNC server.
883 Also optionally set the top visible process name in Linux.
884 Naming of individual threads can also be enabled on Linux to aid debugging.
887 DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
888 "-uuid %08x-%04x-%04x-%04x-%012x\n"
889 " specify machine UUID\n", QEMU_ARCH_ALL)
891 @item -uuid @var{uuid}
901 DEFHEADING(Block device options:)
906 DEF("fda", HAS_ARG, QEMU_OPTION_fda,
907 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
908 DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
910 @item -fda @var{file}
911 @itemx -fdb @var{file}
914 Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
917 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
918 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
919 DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
920 DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
921 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
922 DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
924 @item -hda @var{file}
925 @itemx -hdb @var{file}
926 @itemx -hdc @var{file}
927 @itemx -hdd @var{file}
932 Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
935 DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
936 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
939 @item -cdrom @var{file}
941 Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
942 @option{-cdrom} at the same time). You can use the host CD-ROM by
943 using @file{/dev/cdrom} as filename (@pxref{host_drives}).
946 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
947 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
948 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
949 " [,read-only=on|off][,auto-read-only=on|off]\n"
950 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
951 " [,driver specific parameters...]\n"
952 " configure a block backend\n", QEMU_ARCH_ALL)
954 @item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
957 Define a new block driver node. Some of the options apply to all block drivers,
958 other options are only accepted for a specific block driver. See below for a
959 list of generic options and options for the most common block drivers.
961 Options that expect a reference to another node (e.g. @code{file}) can be
962 given in two ways. Either you specify the node name of an already existing node
963 (file=@var{node-name}), or you define a new node inline, adding options
964 for the referenced node after a dot (file.filename=@var{path},file.aio=native).
966 A block driver node created with @option{-blockdev} can be used for a guest
967 device by specifying its node name for the @code{drive} property in a
968 @option{-device} argument that defines a block device.
971 @item Valid options for any block driver node:
975 Specifies the block driver to use for the given node.
977 This defines the name of the block driver node by which it will be referenced
978 later. The name must be unique, i.e. it must not match the name of a different
979 block driver node, or (if you use @option{-drive} as well) the ID of a drive.
981 If no node name is specified, it is automatically generated. The generated node
982 name is not intended to be predictable and changes between QEMU invocations.
983 For the top level, an explicit node name must be specified.
985 Open the node read-only. Guest write attempts will fail.
987 Note that some block drivers support only read-only access, either generally or
988 in certain configurations. In this case, the default value
989 @option{read-only=off} does not work and the option must be specified
992 If @option{auto-read-only=on} is set, QEMU may fall back to read-only usage
993 even when @option{read-only=off} is requested, or even switch between modes as
994 needed, e.g. depending on whether the image file is writable or whether a
995 writing user is attached to the node.
997 Override the image locking system of QEMU by forcing the node to utilize
998 weaker shared access for permissions where it would normally request exclusive
999 access. When there is the potential for multiple instances to have the same
1000 file open (whether this invocation of QEMU is the first or the second
1001 instance), both instances must permit shared access for the second instance to
1002 succeed at opening the file.
1004 Enabling @option{force-share=on} requires @option{read-only=on}.
1006 The host page cache can be avoided with @option{cache.direct=on}. This will
1007 attempt to do disk IO directly to the guest's memory. QEMU may still perform an
1008 internal copy of the data.
1009 @item cache.no-flush
1010 In case you don't care about data integrity over host failures, you can use
1011 @option{cache.no-flush=on}. This option tells QEMU that it never needs to write
1012 any data to the disk but can instead keep things in cache. If anything goes
1013 wrong, like your host losing power, the disk storage getting disconnected
1014 accidentally, etc. your image will most probably be rendered unusable.
1015 @item discard=@var{discard}
1016 @var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls
1017 whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are
1018 ignored or passed to the filesystem. Some machine types may not support
1020 @item detect-zeroes=@var{detect-zeroes}
1021 @var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic
1022 conversion of plain zero writes by the OS to driver specific optimized
1023 zero write commands. You may even choose "unmap" if @var{discard} is set
1024 to "unmap" to allow a zero write to be converted to an @code{unmap} operation.
1027 @item Driver-specific options for @code{file}
1029 This is the protocol-level block driver for accessing regular files.
1033 The path to the image file in the local filesystem
1035 Specifies the AIO backend (threads/native, default: threads)
1037 Specifies whether the image file is protected with Linux OFD / POSIX locks. The
1038 default is to use the Linux Open File Descriptor API if available, otherwise no
1039 lock is applied. (auto/on/off, default: auto)
1043 -blockdev driver=file,node-name=disk,filename=disk.img
1046 @item Driver-specific options for @code{raw}
1048 This is the image format block driver for raw images. It is usually
1049 stacked on top of a protocol level block driver such as @code{file}.
1053 Reference to or definition of the data source block driver node
1054 (e.g. a @code{file} driver node)
1058 -blockdev driver=file,node-name=disk_file,filename=disk.img
1059 -blockdev driver=raw,node-name=disk,file=disk_file
1063 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
1066 @item Driver-specific options for @code{qcow2}
1068 This is the image format block driver for qcow2 images. It is usually
1069 stacked on top of a protocol level block driver such as @code{file}.
1073 Reference to or definition of the data source block driver node
1074 (e.g. a @code{file} driver node)
1077 Reference to or definition of the backing file block device (default is taken
1078 from the image file). It is allowed to pass @code{null} here in order to disable
1079 the default backing file.
1081 @item lazy-refcounts
1082 Whether to enable the lazy refcounts feature (on/off; default is taken from the
1086 The maximum total size of the L2 table and refcount block caches in bytes
1087 (default: the sum of l2-cache-size and refcount-cache-size)
1090 The maximum size of the L2 table cache in bytes
1091 (default: if cache-size is not specified - 32M on Linux platforms, and 8M on
1092 non-Linux platforms; otherwise, as large as possible within the cache-size,
1093 while permitting the requested or the minimal refcount cache size)
1095 @item refcount-cache-size
1096 The maximum size of the refcount block cache in bytes
1097 (default: 4 times the cluster size; or if cache-size is specified, the part of
1098 it which is not used for the L2 cache)
1100 @item cache-clean-interval
1101 Clean unused entries in the L2 and refcount caches. The interval is in seconds.
1102 The default value is 600 on supporting platforms, and 0 on other platforms.
1103 Setting it to 0 disables this feature.
1105 @item pass-discard-request
1106 Whether discard requests to the qcow2 device should be forwarded to the data
1107 source (on/off; default: on if discard=unmap is specified, off otherwise)
1109 @item pass-discard-snapshot
1110 Whether discard requests for the data source should be issued when a snapshot
1111 operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off;
1114 @item pass-discard-other
1115 Whether discard requests for the data source should be issued on other
1116 occasions where a cluster gets freed (on/off; default: off)
1119 Which overlap checks to perform for writes to the image
1120 (none/constant/cached/all; default: cached). For details or finer
1121 granularity control refer to the QAPI documentation of @code{blockdev-add}.
1126 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1127 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1131 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1134 @item Driver-specific options for other drivers
1135 Please refer to the QAPI documentation of the @code{blockdev-add} QMP command.
1141 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1142 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1143 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1144 " [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1145 " [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n"
1146 " [,readonly=on|off][,copy-on-read=on|off]\n"
1147 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1148 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1149 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1150 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1151 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1152 " [[,iops_size=is]]\n"
1154 " use 'file' as a drive image\n", QEMU_ARCH_ALL)
1156 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
1159 Define a new drive. This includes creating a block driver node (the backend) as
1160 well as a guest device, and is mostly a shortcut for defining the corresponding
1161 @option{-blockdev} and @option{-device} options.
1163 @option{-drive} accepts all options that are accepted by @option{-blockdev}. In
1164 addition, it knows the following options:
1167 @item file=@var{file}
1168 This option defines which disk image (@pxref{disk_images}) to use with
1169 this drive. If the filename contains comma, you must double it
1170 (for instance, "file=my,,file" to use file "my,file").
1172 Special files such as iSCSI devices can be specified using protocol
1173 specific URLs. See the section for "Device URL Syntax" for more information.
1174 @item if=@var{interface}
1175 This option defines on which type on interface the drive is connected.
1176 Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none.
1177 @item bus=@var{bus},unit=@var{unit}
1178 These options define where is connected the drive by defining the bus number and
1180 @item index=@var{index}
1181 This option defines where is connected the drive by using an index in the list
1182 of available connectors of a given interface type.
1183 @item media=@var{media}
1184 This option defines the type of the media: disk or cdrom.
1185 @item snapshot=@var{snapshot}
1186 @var{snapshot} is "on" or "off" and controls snapshot mode for the given drive
1187 (see @option{-snapshot}).
1188 @item cache=@var{cache}
1189 @var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough"
1190 and controls how the host cache is used to access block data. This is a
1191 shortcut that sets the @option{cache.direct} and @option{cache.no-flush}
1192 options (as in @option{-blockdev}), and additionally @option{cache.writeback},
1193 which provides a default for the @option{write-cache} option of block guest
1194 devices (as in @option{-device}). The modes correspond to the following
1197 @c Our texi2pod.pl script doesn't support @multitable, so fall back to using
1198 @c plain ASCII art (well, UTF-8 art really). This looks okay both in the manpage
1199 @c and the HTML output.
1201 @ │ cache.writeback cache.direct cache.no-flush
1202 ─────────────┼─────────────────────────────────────────────────
1203 writeback │ on off off
1205 writethrough │ off off off
1206 directsync │ off on off
1207 unsafe │ on off on
1210 The default mode is @option{cache=writeback}.
1213 @var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
1214 @item format=@var{format}
1215 Specify which disk @var{format} will be used rather than detecting
1216 the format. Can be used to specify format=raw to avoid interpreting
1217 an untrusted format header.
1218 @item werror=@var{action},rerror=@var{action}
1219 Specify which @var{action} to take on write and read errors. Valid actions are:
1220 "ignore" (ignore the error and try to continue), "stop" (pause QEMU),
1221 "report" (report the error to the guest), "enospc" (pause QEMU only if the
1222 host disk is full; report the error to the guest otherwise).
1223 The default setting is @option{werror=enospc} and @option{rerror=report}.
1224 @item copy-on-read=@var{copy-on-read}
1225 @var{copy-on-read} is "on" or "off" and enables whether to copy read backing
1226 file sectors into the image file.
1227 @item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
1228 Specify bandwidth throttling limits in bytes per second, either for all request
1229 types or for reads or writes only. Small values can lead to timeouts or hangs
1230 inside the guest. A safe minimum for disks is 2 MB/s.
1231 @item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm}
1232 Specify bursts in bytes per second, either for all request types or for reads
1233 or writes only. Bursts allow the guest I/O to spike above the limit
1235 @item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
1236 Specify request rate limits in requests per second, either for all request
1237 types or for reads or writes only.
1238 @item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
1239 Specify bursts in requests per second, either for all request types or for reads
1240 or writes only. Bursts allow the guest I/O to spike above the limit
1242 @item iops_size=@var{is}
1243 Let every @var{is} bytes of a request count as a new request for iops
1244 throttling purposes. Use this option to prevent guests from circumventing iops
1245 limits by sending fewer but larger requests.
1247 Join a throttling quota group with given name @var{g}. All drives that are
1248 members of the same group are accounted for together. Use this option to
1249 prevent guests from circumventing throttling limits by using many small disks
1250 instead of a single larger disk.
1253 By default, the @option{cache.writeback=on} mode is used. It will report data
1254 writes as completed as soon as the data is present in the host page cache.
1255 This is safe as long as your guest OS makes sure to correctly flush disk caches
1256 where needed. If your guest OS does not handle volatile disk write caches
1257 correctly and your host crashes or loses power, then the guest may experience
1260 For such guests, you should consider using @option{cache.writeback=off}. This
1261 means that the host page cache will be used to read and write data, but write
1262 notification will be sent to the guest only after QEMU has made sure to flush
1263 each write to the disk. Be aware that this has a major impact on performance.
1265 When using the @option{-snapshot} option, unsafe caching is always used.
1267 Copy-on-read avoids accessing the same backing file sectors repeatedly and is
1268 useful when the backing file is over a slow network. By default copy-on-read
1271 Instead of @option{-cdrom} you can use:
1273 @value{qemu_system} -drive file=file,index=2,media=cdrom
1276 Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
1279 @value{qemu_system} -drive file=file,index=0,media=disk
1280 @value{qemu_system} -drive file=file,index=1,media=disk
1281 @value{qemu_system} -drive file=file,index=2,media=disk
1282 @value{qemu_system} -drive file=file,index=3,media=disk
1285 You can open an image using pre-opened file descriptors from an fd set:
1287 @value{qemu_system} \
1288 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \
1289 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \
1290 -drive file=/dev/fdset/2,index=0,media=disk
1293 You can connect a CDROM to the slave of ide0:
1295 @value{qemu_system_x86} -drive file=file,if=ide,index=1,media=cdrom
1298 If you don't specify the "file=" argument, you define an empty drive:
1300 @value{qemu_system_x86} -drive if=ide,index=1,media=cdrom
1303 Instead of @option{-fda}, @option{-fdb}, you can use:
1305 @value{qemu_system_x86} -drive file=file,index=0,if=floppy
1306 @value{qemu_system_x86} -drive file=file,index=1,if=floppy
1309 By default, @var{interface} is "ide" and @var{index} is automatically
1312 @value{qemu_system_x86} -drive file=a -drive file=b"
1314 is interpreted like:
1316 @value{qemu_system_x86} -hda a -hdb b
1320 DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1321 "-mtdblock file use 'file' as on-board Flash memory image\n",
1324 @item -mtdblock @var{file}
1326 Use @var{file} as on-board Flash memory image.
1329 DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1330 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1332 @item -sd @var{file}
1334 Use @var{file} as SecureDigital card image.
1337 DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
1338 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
1340 @item -pflash @var{file}
1342 Use @var{file} as a parallel flash image.
1345 DEF("snapshot", 0, QEMU_OPTION_snapshot,
1346 "-snapshot write to temporary files instead of disk image files\n",
1351 Write to temporary files instead of disk image files. In this case,
1352 the raw disk image you use is not written back. You can however force
1353 the write back by pressing @key{C-a s} (@pxref{disk_images}).
1356 DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1357 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1358 " [,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n"
1359 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1360 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1361 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1362 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1363 " [[,throttling.iops-size=is]]\n"
1364 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly]\n"
1365 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly]\n"
1366 "-fsdev synth,id=id\n",
1371 @item -fsdev local,id=@var{id},path=@var{path},security_model=@var{security_model} [,writeout=@var{writeout}][,readonly][,fmode=@var{fmode}][,dmode=@var{dmode}] [,throttling.@var{option}=@var{value}[,throttling.@var{option}=@var{value}[,...]]]
1372 @itemx -fsdev proxy,id=@var{id},socket=@var{socket}[,writeout=@var{writeout}][,readonly]
1373 @itemx -fsdev proxy,id=@var{id},sock_fd=@var{sock_fd}[,writeout=@var{writeout}][,readonly]
1374 @itemx -fsdev synth,id=@var{id}[,readonly]
1376 Define a new file system device. Valid options are:
1379 Accesses to the filesystem are done by QEMU.
1381 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1383 Synthetic filesystem, only used by QTests.
1385 Specifies identifier for this device.
1386 @item path=@var{path}
1387 Specifies the export path for the file system device. Files under
1388 this path will be available to the 9p client on the guest.
1389 @item security_model=@var{security_model}
1390 Specifies the security model to be used for this export path.
1391 Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1392 In "passthrough" security model, files are stored using the same
1393 credentials as they are created on the guest. This requires QEMU
1394 to run as root. In "mapped-xattr" security model, some of the file
1395 attributes like uid, gid, mode bits and link target are stored as
1396 file attributes. For "mapped-file" these attributes are stored in the
1397 hidden .virtfs_metadata directory. Directories exported by this security model cannot
1398 interact with other unix tools. "none" security model is same as
1399 passthrough except the sever won't report failures if it fails to
1400 set file attributes like ownership. Security model is mandatory
1401 only for local fsdriver. Other fsdrivers (like proxy) don't take
1402 security model as a parameter.
1403 @item writeout=@var{writeout}
1404 This is an optional argument. The only supported value is "immediate".
1405 This means that host page cache will be used to read and write data but
1406 write notification will be sent to the guest only when the data has been
1407 reported as written by the storage subsystem.
1409 Enables exporting 9p share as a readonly mount for guests. By default
1410 read-write access is given.
1411 @item socket=@var{socket}
1412 Enables proxy filesystem driver to use passed socket file for communicating
1413 with virtfs-proxy-helper(1).
1414 @item sock_fd=@var{sock_fd}
1415 Enables proxy filesystem driver to use passed socket descriptor for
1416 communicating with virtfs-proxy-helper(1). Usually a helper like libvirt
1417 will create socketpair and pass one of the fds as sock_fd.
1418 @item fmode=@var{fmode}
1419 Specifies the default mode for newly created files on the host. Works only
1420 with security models "mapped-xattr" and "mapped-file".
1421 @item dmode=@var{dmode}
1422 Specifies the default mode for newly created directories on the host. Works
1423 only with security models "mapped-xattr" and "mapped-file".
1424 @item throttling.bps-total=@var{b},throttling.bps-read=@var{r},throttling.bps-write=@var{w}
1425 Specify bandwidth throttling limits in bytes per second, either for all request
1426 types or for reads or writes only.
1427 @item throttling.bps-total-max=@var{bm},bps-read-max=@var{rm},bps-write-max=@var{wm}
1428 Specify bursts in bytes per second, either for all request types or for reads
1429 or writes only. Bursts allow the guest I/O to spike above the limit
1431 @item throttling.iops-total=@var{i},throttling.iops-read=@var{r}, throttling.iops-write=@var{w}
1432 Specify request rate limits in requests per second, either for all request
1433 types or for reads or writes only.
1434 @item throttling.iops-total-max=@var{im},throttling.iops-read-max=@var{irm}, throttling.iops-write-max=@var{iwm}
1435 Specify bursts in requests per second, either for all request types or for reads
1436 or writes only. Bursts allow the guest I/O to spike above the limit temporarily.
1437 @item throttling.iops-size=@var{is}
1438 Let every @var{is} bytes of a request count as a new request for iops
1439 throttling purposes.
1442 -fsdev option is used along with -device driver "virtio-9p-...".
1443 @item -device virtio-9p-@var{type},fsdev=@var{id},mount_tag=@var{mount_tag}
1444 Options for virtio-9p-... driver are:
1447 Specifies the variant to be used. Supported values are "pci", "ccw" or "device",
1448 depending on the machine type.
1449 @item fsdev=@var{id}
1450 Specifies the id value specified along with -fsdev option.
1451 @item mount_tag=@var{mount_tag}
1452 Specifies the tag name to be used by the guest to mount this export point.
1457 DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1458 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1459 " [,id=id][,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n"
1460 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly]\n"
1461 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly]\n"
1462 "-virtfs synth,mount_tag=tag[,id=id][,readonly]\n",
1467 @item -virtfs local,path=@var{path},mount_tag=@var{mount_tag} ,security_model=@var{security_model}[,writeout=@var{writeout}][,readonly] [,fmode=@var{fmode}][,dmode=@var{dmode}][,multidevs=@var{multidevs}]
1468 @itemx -virtfs proxy,socket=@var{socket},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly]
1469 @itemx -virtfs proxy,sock_fd=@var{sock_fd},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly]
1470 @itemx -virtfs synth,mount_tag=@var{mount_tag}
1473 Define a new filesystem device and expose it to the guest using a virtio-9p-device. The general form of a Virtual File system pass-through options are:
1476 Accesses to the filesystem are done by QEMU.
1478 Accesses to the filesystem are done by virtfs-proxy-helper(1).
1480 Synthetic filesystem, only used by QTests.
1482 Specifies identifier for the filesystem device
1483 @item path=@var{path}
1484 Specifies the export path for the file system device. Files under
1485 this path will be available to the 9p client on the guest.
1486 @item security_model=@var{security_model}
1487 Specifies the security model to be used for this export path.
1488 Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1489 In "passthrough" security model, files are stored using the same
1490 credentials as they are created on the guest. This requires QEMU
1491 to run as root. In "mapped-xattr" security model, some of the file
1492 attributes like uid, gid, mode bits and link target are stored as
1493 file attributes. For "mapped-file" these attributes are stored in the
1494 hidden .virtfs_metadata directory. Directories exported by this security model cannot
1495 interact with other unix tools. "none" security model is same as
1496 passthrough except the sever won't report failures if it fails to
1497 set file attributes like ownership. Security model is mandatory only
1498 for local fsdriver. Other fsdrivers (like proxy) don't take security
1499 model as a parameter.
1500 @item writeout=@var{writeout}
1501 This is an optional argument. The only supported value is "immediate".
1502 This means that host page cache will be used to read and write data but
1503 write notification will be sent to the guest only when the data has been
1504 reported as written by the storage subsystem.
1506 Enables exporting 9p share as a readonly mount for guests. By default
1507 read-write access is given.
1508 @item socket=@var{socket}
1509 Enables proxy filesystem driver to use passed socket file for
1510 communicating with virtfs-proxy-helper(1). Usually a helper like libvirt
1511 will create socketpair and pass one of the fds as sock_fd.
1513 Enables proxy filesystem driver to use passed 'sock_fd' as the socket
1514 descriptor for interfacing with virtfs-proxy-helper(1).
1515 @item fmode=@var{fmode}
1516 Specifies the default mode for newly created files on the host. Works only
1517 with security models "mapped-xattr" and "mapped-file".
1518 @item dmode=@var{dmode}
1519 Specifies the default mode for newly created directories on the host. Works
1520 only with security models "mapped-xattr" and "mapped-file".
1521 @item mount_tag=@var{mount_tag}
1522 Specifies the tag name to be used by the guest to mount this export point.
1523 @item multidevs=@var{multidevs}
1524 Specifies how to deal with multiple devices being shared with a 9p export.
1525 Supported behaviours are either "remap", "forbid" or "warn". The latter is
1526 the default behaviour on which virtfs 9p expects only one device to be
1527 shared with the same export, and if more than one device is shared and
1528 accessed via the same 9p export then only a warning message is logged
1529 (once) by qemu on host side. In order to avoid file ID collisions on guest
1530 you should either create a separate virtfs export for each device to be
1531 shared with guests (recommended way) or you might use "remap" instead which
1532 allows you to share multiple devices with only one export instead, which is
1533 achieved by remapping the original inode numbers from host to guest in a
1534 way that would prevent such collisions. Remapping inodes in such use cases
1535 is required because the original device IDs from host are never passed and
1536 exposed on guest. Instead all files of an export shared with virtfs always
1537 share the same device id on guest. So two files with identical inode
1538 numbers but from actually different devices on host would otherwise cause a
1539 file ID collision and hence potential misbehaviours on guest. "forbid" on
1540 the other hand assumes like "warn" that only one device is shared by the
1541 same export, however it will not only log a warning message but also
1542 deny access to additional devices on guest. Note though that "forbid" does
1543 currently not block all possible file access operations (e.g. readdir()
1544 would still return entries from other devices).
1548 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1549 "-iscsi [user=user][,password=password]\n"
1550 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1551 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1552 " [,timeout=timeout]\n"
1553 " iSCSI session parameters\n", QEMU_ARCH_ALL)
1558 Configure iSCSI session parameters.
1566 DEFHEADING(USB options:)
1571 DEF("usb", 0, QEMU_OPTION_usb,
1572 "-usb enable on-board USB host controller (if not enabled by default)\n",
1577 Enable USB emulation on machine types with an on-board USB host controller (if
1578 not enabled by default). Note that on-board USB host controllers may not
1579 support USB 3.0. In this case @option{-device qemu-xhci} can be used instead
1580 on machines with PCI.
1583 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1584 "-usbdevice name add the host or guest USB device 'name'\n",
1588 @item -usbdevice @var{devname}
1590 Add the USB device @var{devname}. Note that this option is deprecated,
1591 please use @code{-device usb-...} instead. @xref{usb_devices}.
1596 Virtual Mouse. This will override the PS/2 mouse emulation when activated.
1599 Pointer device that uses absolute coordinates (like a touchscreen). This
1600 means QEMU is able to report the mouse position without having to grab the
1601 mouse. Also overrides the PS/2 mouse emulation when activated.
1604 Braille device. This will use BrlAPI to display the braille output on a real
1615 DEFHEADING(Display options:)
1620 DEF("display", HAS_ARG, QEMU_OPTION_display,
1621 #if defined(CONFIG_SPICE)
1622 "-display spice-app[,gl=on|off]\n"
1624 #if defined(CONFIG_SDL)
1625 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n"
1626 " [,window_close=on|off][,gl=on|core|es|off]\n"
1628 #if defined(CONFIG_GTK)
1629 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1631 #if defined(CONFIG_VNC)
1632 "-display vnc=<display>[,<optargs>]\n"
1634 #if defined(CONFIG_CURSES)
1635 "-display curses[,charset=<encoding>]\n"
1637 #if defined(CONFIG_OPENGL)
1638 "-display egl-headless[,rendernode=<file>]\n"
1641 " select display backend type\n"
1642 " The default display is equivalent to\n "
1643 #if defined(CONFIG_GTK)
1644 "\"-display gtk\"\n"
1645 #elif defined(CONFIG_SDL)
1646 "\"-display sdl\"\n"
1647 #elif defined(CONFIG_COCOA)
1648 "\"-display cocoa\"\n"
1649 #elif defined(CONFIG_VNC)
1650 "\"-vnc localhost:0,to=99,id=default\"\n"
1652 "\"-display none\"\n"
1656 @item -display @var{type}
1658 Select type of display to use. This option is a replacement for the
1659 old style -sdl/-curses/... options. Valid values for @var{type} are
1662 Display video output via SDL (usually in a separate graphics
1663 window; see the SDL documentation for other possibilities).
1665 Display video output via curses. For graphics device models which
1666 support a text mode, QEMU can display this output using a
1667 curses/ncurses interface. Nothing is displayed when the graphics
1668 device is in graphical mode or if the graphics device does not support
1669 a text mode. Generally only the VGA device models support text mode.
1670 The font charset used by the guest can be specified with the
1671 @code{charset} option, for example @code{charset=CP850} for IBM CP850
1672 encoding. The default is @code{CP437}.
1674 Do not display video output. The guest will still see an emulated
1675 graphics card, but its output will not be displayed to the QEMU
1676 user. This option differs from the -nographic option in that it
1677 only affects what is done with video output; -nographic also changes
1678 the destination of the serial and parallel port data.
1680 Display video output in a GTK window. This interface provides drop-down
1681 menus and other UI elements to configure and control the VM during
1684 Start a VNC server on display <arg>
1686 Offload all OpenGL operations to a local DRI device. For any graphical display,
1687 this display needs to be paired with either VNC or SPICE displays.
1689 Start QEMU as a Spice server and launch the default Spice client
1690 application. The Spice server will redirect the serial consoles and
1691 QEMU monitors. (Since 4.0)
1695 DEF("nographic", 0, QEMU_OPTION_nographic,
1696 "-nographic disable graphical output and redirect serial I/Os to console\n",
1701 Normally, if QEMU is compiled with graphical window support, it displays
1702 output such as guest graphics, guest console, and the QEMU monitor in a
1703 window. With this option, you can totally disable graphical output so
1704 that QEMU is a simple command line application. The emulated serial port
1705 is redirected on the console and muxed with the monitor (unless
1706 redirected elsewhere explicitly). Therefore, you can still use QEMU to
1707 debug a Linux kernel with a serial console. Use @key{C-a h} for help on
1708 switching between the console and monitor.
1711 DEF("curses", 0, QEMU_OPTION_curses,
1712 "-curses shorthand for -display curses\n",
1717 Normally, if QEMU is compiled with graphical window support, it displays
1718 output such as guest graphics, guest console, and the QEMU monitor in a
1719 window. With this option, QEMU can display the VGA output when in text
1720 mode using a curses/ncurses interface. Nothing is displayed in graphical
1724 DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1725 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1730 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
1731 affects the special keys (for fullscreen, monitor-mode switching, etc).
1734 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1735 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1740 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
1741 affects the special keys (for fullscreen, monitor-mode switching, etc).
1744 DEF("no-quit", 0, QEMU_OPTION_no_quit,
1745 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL)
1749 Disable SDL window close capability.
1752 DEF("sdl", 0, QEMU_OPTION_sdl,
1753 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL)
1760 DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1761 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1762 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1763 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1764 " [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n"
1765 " [,tls-ciphers=<list>]\n"
1766 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1767 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1768 " [,sasl][,password=<secret>][,disable-ticketing]\n"
1769 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1770 " [,jpeg-wan-compression=[auto|never|always]]\n"
1771 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
1772 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
1773 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
1774 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1775 " [,gl=[on|off]][,rendernode=<file>]\n"
1777 " at least one of {port, tls-port} is mandatory\n",
1780 @item -spice @var{option}[,@var{option}[,...]]
1782 Enable the spice remote desktop protocol. Valid options are
1787 Set the TCP port spice is listening on for plaintext channels.
1790 Set the IP address spice is listening on. Default is any address.
1795 Force using the specified IP version.
1797 @item password=<secret>
1798 Set the password you need to authenticate.
1801 Require that the client use SASL to authenticate with the spice.
1802 The exact choice of authentication method used is controlled from the
1803 system / user's SASL configuration file for the 'qemu' service. This
1804 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1805 unprivileged user, an environment variable SASL_CONF_PATH can be used
1806 to make it search alternate locations for the service config.
1807 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1808 it is recommended that SASL always be combined with the 'tls' and
1809 'x509' settings to enable use of SSL and server certificates. This
1810 ensures a data encryption preventing compromise of authentication
1813 @item disable-ticketing
1814 Allow client connects without authentication.
1816 @item disable-copy-paste
1817 Disable copy paste between the client and the guest.
1819 @item disable-agent-file-xfer
1820 Disable spice-vdagent based file-xfer between the client and the guest.
1823 Set the TCP port spice is listening on for encrypted channels.
1825 @item x509-dir=<dir>
1826 Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1828 @item x509-key-file=<file>
1829 @itemx x509-key-password=<file>
1830 @itemx x509-cert-file=<file>
1831 @itemx x509-cacert-file=<file>
1832 @itemx x509-dh-key-file=<file>
1833 The x509 file names can also be configured individually.
1835 @item tls-ciphers=<list>
1836 Specify which ciphers to use.
1838 @item tls-channel=[main|display|cursor|inputs|record|playback]
1839 @itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1840 Force specific channel to be used with or without TLS encryption. The
1841 options can be specified multiple times to configure multiple
1842 channels. The special name "default" can be used to set the default
1843 mode. For channels which are not explicitly forced into one mode the
1844 spice client is allowed to pick tls/plaintext as he pleases.
1846 @item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1847 Configure image compression (lossless).
1848 Default is auto_glz.
1850 @item jpeg-wan-compression=[auto|never|always]
1851 @itemx zlib-glz-wan-compression=[auto|never|always]
1852 Configure wan image compression (lossy for slow links).
1855 @item streaming-video=[off|all|filter]
1856 Configure video stream detection. Default is off.
1858 @item agent-mouse=[on|off]
1859 Enable/disable passing mouse events via vdagent. Default is on.
1861 @item playback-compression=[on|off]
1862 Enable/disable audio stream compression (using celt 0.5.1). Default is on.
1864 @item seamless-migration=[on|off]
1865 Enable/disable spice seamless migration. Default is off.
1868 Enable/disable OpenGL context. Default is off.
1870 @item rendernode=<file>
1871 DRM render node for OpenGL rendering. If not specified, it will pick
1872 the first available. (Since 2.9)
1877 DEF("portrait", 0, QEMU_OPTION_portrait,
1878 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
1883 Rotate graphical output 90 deg left (only PXA LCD).
1886 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1887 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
1890 @item -rotate @var{deg}
1892 Rotate graphical output some deg left (only PXA LCD).
1895 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
1896 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
1897 " select video card type\n", QEMU_ARCH_ALL)
1899 @item -vga @var{type}
1901 Select type of VGA card to emulate. Valid values for @var{type} are
1904 Cirrus Logic GD5446 Video card. All Windows versions starting from
1905 Windows 95 should recognize and use this graphic card. For optimal
1906 performances, use 16 bit color depth in the guest and the host OS.
1907 (This card was the default before QEMU 2.2)
1909 Standard VGA card with Bochs VBE extensions. If your guest OS
1910 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1911 to use high resolution modes (>= 1280x1024x16) then you should use
1912 this option. (This card is the default since QEMU 2.2)
1914 VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1915 recent XFree86/XOrg server or Windows guest with a driver for this
1918 QXL paravirtual graphic card. It is VGA compatible (including VESA
1919 2.0 VBE support). Works best with qxl guest drivers installed though.
1920 Recommended choice when using the spice protocol.
1922 (sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1923 sun4m machines and offers both 8-bit and 24-bit colour depths at a
1924 fixed resolution of 1024x768.
1926 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1927 for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1928 resolutions aimed at people wishing to run older Solaris versions.
1936 DEF("full-screen", 0, QEMU_OPTION_full_screen,
1937 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
1940 @findex -full-screen
1941 Start in full screen.
1944 DEF("g", 1, QEMU_OPTION_g ,
1945 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
1946 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K)
1948 @item -g @var{width}x@var{height}[x@var{depth}]
1950 Set the initial graphical resolution and depth (PPC, SPARC only).
1953 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1954 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1956 @item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1958 Normally, if QEMU is compiled with graphical window support, it displays
1959 output such as guest graphics, guest console, and the QEMU monitor in a
1960 window. With this option, you can have QEMU listen on VNC display
1961 @var{display} and redirect the VGA display over the VNC session. It is
1962 very useful to enable the usb tablet device when using this option
1963 (option @option{-device usb-tablet}). When using the VNC display, you
1964 must use the @option{-k} parameter to set the keyboard layout if you are
1965 not using en-us. Valid syntax for the @var{display} is
1971 With this option, QEMU will try next available VNC @var{display}s, until the
1972 number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1973 available, e.g. port 5900+@var{display} is already used by another
1974 application. By default, to=0.
1976 @item @var{host}:@var{d}
1978 TCP connections will only be allowed from @var{host} on display @var{d}.
1979 By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1980 be omitted in which case the server will accept connections from any host.
1982 @item unix:@var{path}
1984 Connections will be allowed over UNIX domain sockets where @var{path} is the
1985 location of a unix socket to listen for connections on.
1989 VNC is initialized but not started. The monitor @code{change} command
1990 can be used to later start the VNC server.
1994 Following the @var{display} value there may be one or more @var{option} flags
1995 separated by commas. Valid options are
2001 Connect to a listening VNC client via a ``reverse'' connection. The
2002 client is specified by the @var{display}. For reverse network
2003 connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
2004 is a TCP port number, not a display number.
2008 Opens an additional TCP listening port dedicated to VNC Websocket connections.
2009 If a bare @var{websocket} option is given, the Websocket port is
2010 5700+@var{display}. An alternative port can be specified with the
2011 syntax @code{websocket}=@var{port}.
2013 If @var{host} is specified connections will only be allowed from this host.
2014 It is possible to control the websocket listen address independently, using
2015 the syntax @code{websocket}=@var{host}:@var{port}.
2017 If no TLS credentials are provided, the websocket connection runs in
2018 unencrypted mode. If TLS credentials are provided, the websocket connection
2019 requires encrypted client connections.
2023 Require that password based authentication is used for client connections.
2025 The password must be set separately using the @code{set_password} command in
2026 the @ref{pcsys_monitor}. The syntax to change your password is:
2027 @code{set_password <protocol> <password>} where <protocol> could be either
2030 If you would like to change <protocol> password expiration, you should use
2031 @code{expire_password <protocol> <expiration-time>} where expiration time could
2032 be one of the following options: now, never, +seconds or UNIX time of
2033 expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
2034 to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
2037 You can also use keywords "now" or "never" for the expiration time to
2038 allow <protocol> password to expire immediately or never expire.
2040 @item tls-creds=@var{ID}
2042 Provides the ID of a set of TLS credentials to use to secure the
2043 VNC server. They will apply to both the normal VNC server socket
2044 and the websocket socket (if enabled). Setting TLS credentials
2045 will cause the VNC server socket to enable the VeNCrypt auth
2046 mechanism. The credentials should have been previously created
2047 using the @option{-object tls-creds} argument.
2049 @item tls-authz=@var{ID}
2051 Provides the ID of the QAuthZ authorization object against which
2052 the client's x509 distinguished name will validated. This object is
2053 only resolved at time of use, so can be deleted and recreated on the
2054 fly while the VNC server is active. If missing, it will default
2059 Require that the client use SASL to authenticate with the VNC server.
2060 The exact choice of authentication method used is controlled from the
2061 system / user's SASL configuration file for the 'qemu' service. This
2062 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
2063 unprivileged user, an environment variable SASL_CONF_PATH can be used
2064 to make it search alternate locations for the service config.
2065 While some SASL auth methods can also provide data encryption (eg GSSAPI),
2066 it is recommended that SASL always be combined with the 'tls' and
2067 'x509' settings to enable use of SSL and server certificates. This
2068 ensures a data encryption preventing compromise of authentication
2069 credentials. See the @ref{vnc_security} section for details on using
2070 SASL authentication.
2072 @item sasl-authz=@var{ID}
2074 Provides the ID of the QAuthZ authorization object against which
2075 the client's SASL username will validated. This object is
2076 only resolved at time of use, so can be deleted and recreated on the
2077 fly while the VNC server is active. If missing, it will default
2082 Legacy method for enabling authorization of clients against the
2083 x509 distinguished name and SASL username. It results in the creation
2084 of two @code{authz-list} objects with IDs of @code{vnc.username} and
2085 @code{vnc.x509dname}. The rules for these objects must be configured
2086 with the HMP ACL commands.
2088 This option is deprecated and should no longer be used. The new
2089 @option{sasl-authz} and @option{tls-authz} options are a
2094 Enable lossy compression methods (gradient, JPEG, ...). If this
2095 option is set, VNC client may receive lossy framebuffer updates
2096 depending on its encoding settings. Enabling this option can save
2097 a lot of bandwidth at the expense of quality.
2101 Disable adaptive encodings. Adaptive encodings are enabled by default.
2102 An adaptive encoding will try to detect frequently updated screen regions,
2103 and send updates in these regions using a lossy encoding (like JPEG).
2104 This can be really helpful to save bandwidth when playing videos. Disabling
2105 adaptive encodings restores the original static behavior of encodings
2108 @item share=[allow-exclusive|force-shared|ignore]
2110 Set display sharing policy. 'allow-exclusive' allows clients to ask
2111 for exclusive access. As suggested by the rfb spec this is
2112 implemented by dropping other connections. Connecting multiple
2113 clients in parallel requires all clients asking for a shared session
2114 (vncviewer: -shared switch). This is the default. 'force-shared'
2115 disables exclusive client access. Useful for shared desktop sessions,
2116 where you don't want someone forgetting specify -shared disconnect
2117 everybody else. 'ignore' completely ignores the shared flag and
2118 allows everybody connect unconditionally. Doesn't conform to the rfb
2119 spec but is traditional QEMU behavior.
2123 Set keyboard delay, for key down and key up events, in milliseconds.
2124 Default is 10. Keyboards are low-bandwidth devices, so this slowdown
2125 can help the device and guest to keep up and not lose events in case
2126 events are arriving in bulk. Possible causes for the latter are flaky
2127 network connections, or scripts for automated testing.
2129 @item audiodev=@var{audiodev}
2131 Use the specified @var{audiodev} when the VNC client requests audio
2132 transmission. When not using an -audiodev argument, this option must
2133 be omitted, otherwise is must be present and specify a valid audiodev.
2141 ARCHHEADING(, QEMU_ARCH_I386)
2143 ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
2148 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2149 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2154 Use it when installing Windows 2000 to avoid a disk full bug. After
2155 Windows 2000 is installed, you no longer need this option (this option
2156 slows down the IDE transfers).
2159 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2160 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2163 @item -no-fd-bootchk
2164 @findex -no-fd-bootchk
2165 Disable boot signature checking for floppy disks in BIOS. May
2166 be needed to boot from old floppy disks.
2169 DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2170 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2174 Disable ACPI (Advanced Configuration and Power Interface) support. Use
2175 it if your guest OS complains about ACPI problems (PC target machine
2179 DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2180 "-no-hpet disable HPET\n", QEMU_ARCH_I386)
2184 Disable HPET support.
2187 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2188 "-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"
2189 " ACPI table description\n", QEMU_ARCH_I386)
2191 @item -acpitable [sig=@var{str}][,rev=@var{n}][,oem_id=@var{str}][,oem_table_id=@var{str}][,oem_rev=@var{n}] [,asl_compiler_id=@var{str}][,asl_compiler_rev=@var{n}][,data=@var{file1}[:@var{file2}]...]
2193 Add ACPI table with specified header fields and context from specified files.
2194 For file=, take whole ACPI table from the specified files, including all
2195 ACPI headers (possible overridden by other options).
2196 For data=, only data
2197 portion of the table is used, all header information is specified in the
2199 If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id
2200 fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
2201 to ensure the field matches required by the Microsoft SLIC spec and the ACPI
2205 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2206 "-smbios file=binary\n"
2207 " load SMBIOS entry from binary file\n"
2208 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2210 " specify SMBIOS type 0 fields\n"
2211 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2212 " [,uuid=uuid][,sku=str][,family=str]\n"
2213 " specify SMBIOS type 1 fields\n"
2214 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2215 " [,asset=str][,location=str]\n"
2216 " specify SMBIOS type 2 fields\n"
2217 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2219 " specify SMBIOS type 3 fields\n"
2220 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2221 " [,asset=str][,part=str]\n"
2222 " specify SMBIOS type 4 fields\n"
2223 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2224 " [,asset=str][,part=str][,speed=%d]\n"
2225 " specify SMBIOS type 17 fields\n",
2226 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2228 @item -smbios file=@var{binary}
2230 Load SMBIOS entry from binary file.
2232 @item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
2233 Specify SMBIOS type 0 fields
2235 @item -smbios type=1[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,uuid=@var{uuid}][,sku=@var{str}][,family=@var{str}]
2236 Specify SMBIOS type 1 fields
2238 @item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}]
2239 Specify SMBIOS type 2 fields
2241 @item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
2242 Specify SMBIOS type 3 fields
2244 @item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
2245 Specify SMBIOS type 4 fields
2247 @item -smbios type=17[,loc_pfx=@var{str}][,bank=@var{str}][,manufacturer=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}][,speed=@var{%d}]
2248 Specify SMBIOS type 17 fields
2256 DEFHEADING(Network options:)
2261 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2263 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n"
2264 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2265 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2266 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2267 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2269 "[,smb=dir[,smbserver=addr]]\n"
2271 " configure a user mode network backend with ID 'str',\n"
2272 " its DHCP server and optional services\n"
2275 "-netdev tap,id=str,ifname=name\n"
2276 " configure a host TAP network backend with ID 'str'\n"
2278 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2279 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2280 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2282 " configure a host TAP network backend with ID 'str'\n"
2283 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2284 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2285 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2286 " to deconfigure it\n"
2287 " use '[down]script=no' to disable script execution\n"
2288 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2290 " use 'fd=h' to connect to an already opened TAP interface\n"
2291 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2292 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2293 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2294 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2295 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2296 " use vhost=on to enable experimental in kernel accelerator\n"
2297 " (only has effect for virtio guests which use MSIX)\n"
2298 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2299 " use 'vhostfd=h' to connect to an already opened vhost net device\n"
2300 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2301 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2302 " use 'poll-us=n' to speciy the maximum number of microseconds that could be\n"
2303 " spent on busy polling for vhost net\n"
2304 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2305 " configure a host TAP network backend with ID 'str' that is\n"
2306 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2307 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2310 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2311 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n"
2312 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n"
2313 " [,rxcookie=rxcookie][,offset=offset]\n"
2314 " configure a network backend with ID 'str' connected to\n"
2315 " an Ethernet over L2TPv3 pseudowire.\n"
2316 " Linux kernel 3.3+ as well as most routers can talk\n"
2317 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2318 " VM to a router and even VM to Host. It is a nearly-universal\n"
2319 " standard (RFC3391). Note - this implementation uses static\n"
2320 " pre-configured tunnels (same as the Linux kernel).\n"
2321 " use 'src=' to specify source address\n"
2322 " use 'dst=' to specify destination address\n"
2323 " use 'udp=on' to specify udp encapsulation\n"
2324 " use 'srcport=' to specify source udp port\n"
2325 " use 'dstport=' to specify destination udp port\n"
2326 " use 'ipv6=on' to force v6\n"
2327 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2328 " well as a weak security measure\n"
2329 " use 'rxcookie=0x012345678' to specify a rxcookie\n"
2330 " use 'txcookie=0x012345678' to specify a txcookie\n"
2331 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2332 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2333 " use 'pincounter=on' to work around broken counter handling in peer\n"
2334 " use 'offset=X' to add an extra offset between header and data\n"
2336 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2337 " configure a network backend to connect to another network\n"
2338 " using a socket connection\n"
2339 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2340 " configure a network backend to connect to a multicast maddr and port\n"
2341 " use 'localaddr=addr' to specify the host address to send packets from\n"
2342 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2343 " configure a network backend to connect to another network\n"
2344 " using an UDP tunnel\n"
2346 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2347 " configure a network backend to connect to port 'n' of a vde switch\n"
2348 " running on host and listening for incoming connections on 'socketpath'.\n"
2349 " Use group 'groupname' and mode 'octalmode' to change default\n"
2350 " ownership and permissions for communication port.\n"
2352 #ifdef CONFIG_NETMAP
2353 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2354 " attach to the existing netmap-enabled network interface 'name', or to a\n"
2355 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2356 " netmap device, defaults to '/dev/netmap')\n"
2359 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2360 " configure a vhost-user network, backed by a chardev 'dev'\n"
2362 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2363 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2364 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2375 #ifdef CONFIG_NETMAP
2381 "socket][,option][,...][mac=macaddr]\n"
2382 " initialize an on-board / default host NIC (using MAC address\n"
2383 " macaddr) and connect it to the given host network backend\n"
2384 "-nic none use it alone to have zero network devices (the default is to\n"
2385 " provided a 'user' network connection)\n",
2387 DEF("net", HAS_ARG, QEMU_OPTION_net,
2388 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2389 " configure or create an on-board (or machine default) NIC and\n"
2390 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2400 #ifdef CONFIG_NETMAP
2403 "socket][,option][,option][,...]\n"
2404 " old way to initialize a host network interface\n"
2405 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2407 @item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
2409 This option is a shortcut for configuring both the on-board (default) guest
2410 NIC hardware and the host network backend in one go. The host backend options
2411 are the same as with the corresponding @option{-netdev} options below.
2412 The guest NIC model can be set with @option{model=@var{modelname}}.
2413 Use @option{model=help} to list the available device types.
2414 The hardware MAC address can be set with @option{mac=@var{macaddr}}.
2416 The following two example do exactly the same, to show how @option{-nic} can
2417 be used to shorten the command line length (note that the e1000 is the default
2418 on i386, so the @option{model=e1000} parameter could even be omitted here, too):
2420 @value{qemu_system} -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2421 @value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2425 Indicate that no network devices should be configured. It is used to override
2426 the default configuration (default NIC with ``user'' host network backend)
2427 which is activated if no other networking options are provided.
2429 @item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
2431 Configure user mode host network backend which requires no administrator
2432 privilege to run. Valid options are:
2436 Assign symbolic name for use in monitor commands.
2438 @item ipv4=on|off and ipv6=on|off
2439 Specify that either IPv4 or IPv6 must be enabled. If neither is specified
2440 both protocols are enabled.
2442 @item net=@var{addr}[/@var{mask}]
2443 Set IP network address the guest will see. Optionally specify the netmask,
2444 either in the form a.b.c.d or as number of valid top-most bits. Default is
2447 @item host=@var{addr}
2448 Specify the guest-visible address of the host. Default is the 2nd IP in the
2449 guest network, i.e. x.x.x.2.
2451 @item ipv6-net=@var{addr}[/@var{int}]
2452 Set IPv6 network address the guest will see (default is fec0::/64). The
2453 network prefix is given in the usual hexadecimal IPv6 address
2454 notation. The prefix size is optional, and is given as the number of
2455 valid top-most bits (default is 64).
2457 @item ipv6-host=@var{addr}
2458 Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2459 the guest network, i.e. xxxx::2.
2461 @item restrict=on|off
2462 If this option is enabled, the guest will be isolated, i.e. it will not be
2463 able to contact the host and no guest IP packets will be routed over the host
2464 to the outside. This option does not affect any explicitly set forwarding rules.
2466 @item hostname=@var{name}
2467 Specifies the client hostname reported by the built-in DHCP server.
2469 @item dhcpstart=@var{addr}
2470 Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2471 is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2473 @item dns=@var{addr}
2474 Specify the guest-visible address of the virtual nameserver. The address must
2475 be different from the host address. Default is the 3rd IP in the guest network,
2478 @item ipv6-dns=@var{addr}
2479 Specify the guest-visible address of the IPv6 virtual nameserver. The address
2480 must be different from the host address. Default is the 3rd IP in the guest
2481 network, i.e. xxxx::3.
2483 @item dnssearch=@var{domain}
2484 Provides an entry for the domain-search list sent by the built-in
2485 DHCP server. More than one domain suffix can be transmitted by specifying
2486 this option multiple times. If supported, this will cause the guest to
2487 automatically try to append the given domain suffix(es) in case a domain name
2488 can not be resolved.
2492 @value{qemu_system} -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2495 @item domainname=@var{domain}
2496 Specifies the client domain name reported by the built-in DHCP server.
2498 @item tftp=@var{dir}
2499 When using the user mode network stack, activate a built-in TFTP
2500 server. The files in @var{dir} will be exposed as the root of a TFTP server.
2501 The TFTP client on the guest must be configured in binary mode (use the command
2502 @code{bin} of the Unix TFTP client).
2504 @item tftp-server-name=@var{name}
2505 In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
2506 66). This can be used to advise the guest to load boot files or configurations
2507 from a different server than the host address.
2509 @item bootfile=@var{file}
2510 When using the user mode network stack, broadcast @var{file} as the BOOTP
2511 filename. In conjunction with @option{tftp}, this can be used to network boot
2512 a guest from a local directory.
2514 Example (using pxelinux):
2516 @value{qemu_system} -hda linux.img -boot n -device e1000,netdev=n1 \
2517 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2520 @item smb=@var{dir}[,smbserver=@var{addr}]
2521 When using the user mode network stack, activate a built-in SMB
2522 server so that Windows OSes can access to the host files in @file{@var{dir}}
2523 transparently. The IP address of the SMB server can be set to @var{addr}. By
2524 default the 4th IP in the guest network is used, i.e. x.x.x.4.
2526 In the guest Windows OS, the line:
2530 must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2531 or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2533 Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2535 Note that a SAMBA server must be installed on the host OS.
2537 @item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2538 Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2539 the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2540 @var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2541 given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2542 be bound to a specific host interface. If no connection type is set, TCP is
2543 used. This option can be given multiple times.
2545 For example, to redirect host X11 connection from screen 1 to guest
2546 screen 0, use the following:
2550 @value{qemu_system} -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2551 # this host xterm should open in the guest X11 server
2555 To redirect telnet connections from host port 5555 to telnet port on
2556 the guest, use the following:
2560 @value{qemu_system} -nic user,hostfwd=tcp::5555-:23
2561 telnet localhost 5555
2564 Then when you use on the host @code{telnet localhost 5555}, you
2565 connect to the guest telnet server.
2567 @item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2568 @itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2569 Forward guest TCP connections to the IP address @var{server} on port @var{port}
2570 to the character device @var{dev} or to a program executed by @var{cmd:command}
2571 which gets spawned for each connection. This option can be given multiple times.
2573 You can either use a chardev directly and have that one used throughout QEMU's
2574 lifetime, like in the following example:
2577 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2578 # the guest accesses it
2579 @value{qemu_system} -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2582 Or you can execute a command on every TCP connection established by the guest,
2583 so that QEMU behaves similar to an inetd process for that virtual server:
2586 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2587 # and connect the TCP stream to its stdin/stdout
2588 @value{qemu_system} -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2593 @item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
2594 Configure a host TAP network backend with ID @var{id}.
2596 Use the network script @var{file} to configure it and the network script
2597 @var{dfile} to deconfigure it. If @var{name} is not provided, the OS
2598 automatically provides one. The default network configure script is
2599 @file{/etc/qemu-ifup} and the default network deconfigure script is
2600 @file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no}
2601 to disable script execution.
2603 If running QEMU as an unprivileged user, use the network helper
2604 @var{helper} to configure the TAP interface and attach it to the bridge.
2605 The default network helper executable is @file{/path/to/qemu-bridge-helper}
2606 and the default bridge device is @file{br0}.
2608 @option{fd}=@var{h} can be used to specify the handle of an already
2609 opened host TAP interface.
2614 #launch a QEMU instance with the default network script
2615 @value{qemu_system} linux.img -nic tap
2619 #launch a QEMU instance with two NICs, each one connected
2621 @value{qemu_system} linux.img \
2622 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \
2623 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2627 #launch a QEMU instance with the default network helper to
2628 #connect a TAP device to bridge br0
2629 @value{qemu_system} linux.img -device virtio-net-pci,netdev=n1 \
2630 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2633 @item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}]
2634 Connect a host TAP network interface to a host bridge device.
2636 Use the network helper @var{helper} to configure the TAP interface and
2637 attach it to the bridge. The default network helper executable is
2638 @file{/path/to/qemu-bridge-helper} and the default bridge
2639 device is @file{br0}.
2644 #launch a QEMU instance with the default network helper to
2645 #connect a TAP device to bridge br0
2646 @value{qemu_system} linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2650 #launch a QEMU instance with the default network helper to
2651 #connect a TAP device to bridge qemubr0
2652 @value{qemu_system} linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2655 @item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2657 This host network backend can be used to connect the guest's network to
2658 another QEMU virtual machine using a TCP socket connection. If @option{listen}
2659 is specified, QEMU waits for incoming connections on @var{port}
2660 (@var{host} is optional). @option{connect} is used to connect to
2661 another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2662 specifies an already opened TCP socket.
2666 # launch a first QEMU instance
2667 @value{qemu_system} linux.img \
2668 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2669 -netdev socket,id=n1,listen=:1234
2670 # connect the network of this instance to the network of the first instance
2671 @value{qemu_system} linux.img \
2672 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2673 -netdev socket,id=n2,connect=127.0.0.1:1234
2676 @item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2678 Configure a socket host network backend to share the guest's network traffic
2679 with another QEMU virtual machines using a UDP multicast socket, effectively
2680 making a bus for every QEMU with same multicast address @var{maddr} and @var{port}.
2684 Several QEMU can be running on different hosts and share same bus (assuming
2685 correct multicast setup for these hosts).
2687 mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
2688 @url{http://user-mode-linux.sf.net}.
2690 Use @option{fd=h} to specify an already opened UDP multicast socket.
2695 # launch one QEMU instance
2696 @value{qemu_system} linux.img \
2697 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2698 -netdev socket,id=n1,mcast=230.0.0.1:1234
2699 # launch another QEMU instance on same "bus"
2700 @value{qemu_system} linux.img \
2701 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2702 -netdev socket,id=n2,mcast=230.0.0.1:1234
2703 # launch yet another QEMU instance on same "bus"
2704 @value{qemu_system} linux.img \
2705 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \
2706 -netdev socket,id=n3,mcast=230.0.0.1:1234
2709 Example (User Mode Linux compat.):
2711 # launch QEMU instance (note mcast address selected is UML's default)
2712 @value{qemu_system} linux.img \
2713 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2714 -netdev socket,id=n1,mcast=239.192.168.1:1102
2716 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2719 Example (send packets from host's 1.2.3.4):
2721 @value{qemu_system} linux.img \
2722 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2723 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2726 @item -netdev l2tpv3,id=@var{id},src=@var{srcaddr},dst=@var{dstaddr}[,srcport=@var{srcport}][,dstport=@var{dstport}],txsession=@var{txsession}[,rxsession=@var{rxsession}][,ipv6][,udp][,cookie64][,counter][,pincounter][,txcookie=@var{txcookie}][,rxcookie=@var{rxcookie}][,offset=@var{offset}]
2727 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3391) is a
2728 popular protocol to transport Ethernet (and other Layer 2) data frames between
2729 two systems. It is present in routers, firewalls and the Linux kernel
2730 (from version 3.3 onwards).
2732 This transport allows a VM to communicate to another VM, router or firewall directly.
2735 @item src=@var{srcaddr}
2736 source address (mandatory)
2737 @item dst=@var{dstaddr}
2738 destination address (mandatory)
2740 select udp encapsulation (default is ip).
2741 @item srcport=@var{srcport}
2743 @item dstport=@var{dstport}
2744 destination udp port.
2746 force v6, otherwise defaults to v4.
2747 @item rxcookie=@var{rxcookie}
2748 @itemx txcookie=@var{txcookie}
2749 Cookies are a weak form of security in the l2tpv3 specification.
2750 Their function is mostly to prevent misconfiguration. By default they are 32
2753 Set cookie size to 64 bit instead of the default 32
2755 Force a 'cut-down' L2TPv3 with no counter as in
2756 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2758 Work around broken counter handling in peer. This may also help on
2759 networks which have packet reorder.
2760 @item offset=@var{offset}
2761 Add an extra offset between header and data
2764 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan
2765 on the remote Linux host 1.2.3.4:
2767 # Setup tunnel on linux host using raw ip as encapsulation
2769 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \
2770 encap udp udp_sport 16384 udp_dport 16384
2771 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \
2772 0xFFFFFFFF peer_session_id 0xFFFFFFFF
2773 ifconfig vmtunnel0 mtu 1500
2774 ifconfig vmtunnel0 up
2775 brctl addif br-lan vmtunnel0
2779 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2781 @value{qemu_system} linux.img -device e1000,netdev=n1 \
2782 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2786 @item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2787 Configure VDE backend to connect to PORT @var{n} of a vde switch running on host and
2788 listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}
2789 and MODE @var{octalmode} to change default ownership and permissions for
2790 communication port. This option is only available if QEMU has been compiled
2791 with vde support enabled.
2796 vde_switch -F -sock /tmp/myswitch
2797 # launch QEMU instance
2798 @value{qemu_system} linux.img -nic vde,sock=/tmp/myswitch
2801 @item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
2803 Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
2804 be a unix domain socket backed one. The vhost-user uses a specifically defined
2805 protocol to pass vhost ioctl replacement messages to an application on the other
2806 end of the socket. On non-MSIX guests, the feature can be forced with
2807 @var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
2808 be created for multiqueue vhost-user.
2812 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
2813 -numa node,memdev=mem \
2814 -chardev socket,id=chr0,path=/path/to/socket \
2815 -netdev type=vhost-user,id=net0,chardev=chr0 \
2816 -device virtio-net-pci,netdev=net0
2819 @item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}]
2821 Create a hub port on the emulated hub with ID @var{hubid}.
2823 The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2824 single netdev. Alternatively, you can also connect the hubport to another
2825 netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option.
2827 @item -net nic[,netdev=@var{nd}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}]
2829 Legacy option to configure or create an on-board (or machine default) Network
2830 Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e.
2831 the default hub), or to the netdev @var{nd}.
2832 The NIC is an e1000 by default on the PC target. Optionally, the MAC address
2833 can be changed to @var{mac}, the device address set to @var{addr} (PCI cards
2834 only), and a @var{name} can be assigned for use in monitor commands.
2835 Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
2836 that the card should have; this option currently only affects virtio cards; set
2837 @var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
2838 NIC is created. QEMU can emulate several different models of network card.
2839 Use @code{-net nic,model=help} for a list of available devices for your target.
2841 @item -net user|tap|bridge|socket|l2tpv3|vde[,...][,name=@var{name}]
2842 Configure a host network backend (with the options corresponding to the same
2843 @option{-netdev} option) and connect it to the emulated hub 0 (the default
2844 hub). Use @var{name} to specify the name of the hub port.
2852 DEFHEADING(Character device options:)
2854 DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
2856 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2857 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2858 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2859 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
2860 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2861 " [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2862 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2863 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2864 " [,logfile=PATH][,logappend=on|off]\n"
2865 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2866 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2867 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2868 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2869 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2870 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2872 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2873 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2875 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2876 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2878 #ifdef CONFIG_BRLAPI
2879 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2881 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
2882 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
2883 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2884 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2886 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
2887 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2888 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2890 #if defined(CONFIG_SPICE)
2891 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2892 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2899 The general form of a character device option is:
2901 @item -chardev @var{backend},id=@var{id}[,mux=on|off][,@var{options}]
2922 The specific backend will determine the applicable options.
2924 Use @code{-chardev help} to print all available chardev backend types.
2926 All devices must have an id, which can be any string up to 127 characters long.
2927 It is used to uniquely identify this device in other command line directives.
2929 A character device may be used in multiplexing mode by multiple front-ends.
2930 Specify @option{mux=on} to enable this mode.
2931 A multiplexer is a "1:N" device, and here the "1" end is your specified chardev
2932 backend, and the "N" end is the various parts of QEMU that can talk to a chardev.
2933 If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will
2934 create a multiplexer with your specified ID, and you can then configure multiple
2935 front ends to use that chardev ID for their input/output. Up to four different
2936 front ends can be connected to a single multiplexed chardev. (Without
2937 multiplexing enabled, a chardev can only be used by a single front end.)
2938 For instance you could use this to allow a single stdio chardev to be used by
2939 two serial ports and the QEMU monitor:
2942 -chardev stdio,mux=on,id=char0 \
2943 -mon chardev=char0,mode=readline \
2944 -serial chardev:char0 \
2945 -serial chardev:char0
2948 You can have more than one multiplexer in a system configuration; for instance
2949 you could have a TCP port multiplexed between UART 0 and UART 1, and stdio
2950 multiplexed between the QEMU monitor and a parallel port:
2953 -chardev stdio,mux=on,id=char0 \
2954 -mon chardev=char0,mode=readline \
2955 -parallel chardev:char0 \
2956 -chardev tcp,...,mux=on,id=char1 \
2957 -serial chardev:char1 \
2958 -serial chardev:char1
2961 When you're using a multiplexed character device, some escape sequences are
2962 interpreted in the input. @xref{mux_keys, Keys in the character backend
2965 Note that some other command line options may implicitly create multiplexed
2966 character backends; for instance @option{-serial mon:stdio} creates a
2967 multiplexed stdio backend connected to the serial port and the QEMU monitor,
2968 and @option{-nographic} also multiplexes the console and the monitor to
2971 There is currently no support for multiplexing in the other direction
2972 (where a single QEMU front end takes input and output from multiple chardevs).
2974 Every backend supports the @option{logfile} option, which supplies the path
2975 to a file to record all data transmitted via the backend. The @option{logappend}
2976 option controls whether the log file will be truncated or appended to when
2981 The available backends are:
2984 @item -chardev null,id=@var{id}
2985 A void device. This device will not emit any data, and will drop any data it
2986 receives. The null backend does not take any options.
2988 @item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}][,tls-authz=@var{id}]
2990 Create a two-way stream socket, which can be either a TCP or a unix socket. A
2991 unix socket will be created if @option{path} is specified. Behaviour is
2992 undefined if TCP options are specified for a unix socket.
2994 @option{server} specifies that the socket shall be a listening socket.
2996 @option{nowait} specifies that QEMU should not block waiting for a client to
2997 connect to a listening socket.
2999 @option{telnet} specifies that traffic on the socket should interpret telnet
3002 @option{websocket} specifies that the socket uses WebSocket protocol for
3005 @option{reconnect} sets the timeout for reconnecting on non-server sockets when
3006 the remote end goes away. qemu will delay this many seconds and then attempt
3007 to reconnect. Zero disables reconnecting, and is the default.
3009 @option{tls-creds} requests enablement of the TLS protocol for encryption,
3010 and specifies the id of the TLS credentials to use for the handshake. The
3011 credentials must be previously created with the @option{-object tls-creds}
3014 @option{tls-auth} provides the ID of the QAuthZ authorization object against
3015 which the client's x509 distinguished name will be validated. This object is
3016 only resolved at time of use, so can be deleted and recreated on the fly
3017 while the chardev server is active. If missing, it will default to denying
3020 TCP and unix socket options are given below:
3024 @item TCP options: port=@var{port}[,host=@var{host}][,to=@var{to}][,ipv4][,ipv6][,nodelay]
3026 @option{host} for a listening socket specifies the local address to be bound.
3027 For a connecting socket species the remote host to connect to. @option{host} is
3028 optional for listening sockets. If not specified it defaults to @code{0.0.0.0}.
3030 @option{port} for a listening socket specifies the local port to be bound. For a
3031 connecting socket specifies the port on the remote host to connect to.
3032 @option{port} can be given as either a port number or a service name.
3033 @option{port} is required.
3035 @option{to} is only relevant to listening sockets. If it is specified, and
3036 @option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up
3037 to and including @option{to} until it succeeds. @option{to} must be specified
3040 @option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
3041 If neither is specified the socket may use either protocol.
3043 @option{nodelay} disables the Nagle algorithm.
3045 @item unix options: path=@var{path}
3047 @option{path} specifies the local path of the unix socket. @option{path} is
3052 @item -chardev udp,id=@var{id}[,host=@var{host}],port=@var{port}[,localaddr=@var{localaddr}][,localport=@var{localport}][,ipv4][,ipv6]
3054 Sends all traffic from the guest to a remote host over UDP.
3056 @option{host} specifies the remote host to connect to. If not specified it
3057 defaults to @code{localhost}.
3059 @option{port} specifies the port on the remote host to connect to. @option{port}
3062 @option{localaddr} specifies the local address to bind to. If not specified it
3063 defaults to @code{0.0.0.0}.
3065 @option{localport} specifies the local port to bind to. If not specified any
3066 available local port will be used.
3068 @option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
3069 If neither is specified the device may use either protocol.
3071 @item -chardev msmouse,id=@var{id}
3073 Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not
3076 @item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
3078 Connect to a QEMU text console. @option{vc} may optionally be given a specific
3081 @option{width} and @option{height} specify the width and height respectively of
3082 the console, in pixels.
3084 @option{cols} and @option{rows} specify that the console be sized to fit a text
3085 console with the given dimensions.
3087 @item -chardev ringbuf,id=@var{id}[,size=@var{size}]
3089 Create a ring buffer with fixed size @option{size}.
3090 @var{size} must be a power of two and defaults to @code{64K}.
3092 @item -chardev file,id=@var{id},path=@var{path}
3094 Log all traffic received from the guest to a file.
3096 @option{path} specifies the path of the file to be opened. This file will be
3097 created if it does not already exist, and overwritten if it does. @option{path}
3100 @item -chardev pipe,id=@var{id},path=@var{path}
3102 Create a two-way connection to the guest. The behaviour differs slightly between
3103 Windows hosts and other hosts:
3105 On Windows, a single duplex pipe will be created at
3106 @file{\\.pipe\@option{path}}.
3108 On other hosts, 2 pipes will be created called @file{@option{path}.in} and
3109 @file{@option{path}.out}. Data written to @file{@option{path}.in} will be
3110 received by the guest. Data written by the guest can be read from
3111 @file{@option{path}.out}. QEMU will not create these fifos, and requires them to
3114 @option{path} forms part of the pipe path as described above. @option{path} is
3117 @item -chardev console,id=@var{id}
3119 Send traffic from the guest to QEMU's standard output. @option{console} does not
3122 @option{console} is only available on Windows hosts.
3124 @item -chardev serial,id=@var{id},path=@option{path}
3126 Send traffic from the guest to a serial device on the host.
3128 On Unix hosts serial will actually accept any tty device,
3129 not only serial lines.
3131 @option{path} specifies the name of the serial device to open.
3133 @item -chardev pty,id=@var{id}
3135 Create a new pseudo-terminal on the host and connect to it. @option{pty} does
3136 not take any options.
3138 @option{pty} is not available on Windows hosts.
3140 @item -chardev stdio,id=@var{id}[,signal=on|off]
3141 Connect to standard input and standard output of the QEMU process.
3143 @option{signal} controls if signals are enabled on the terminal, that includes
3144 exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
3145 default, use @option{signal=off} to disable it.
3147 @item -chardev braille,id=@var{id}
3149 Connect to a local BrlAPI server. @option{braille} does not take any options.
3151 @item -chardev tty,id=@var{id},path=@var{path}
3153 @option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
3154 DragonFlyBSD hosts. It is an alias for @option{serial}.
3156 @option{path} specifies the path to the tty. @option{path} is required.
3158 @item -chardev parallel,id=@var{id},path=@var{path}
3159 @itemx -chardev parport,id=@var{id},path=@var{path}
3161 @option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
3163 Connect to a local parallel port.
3165 @option{path} specifies the path to the parallel port device. @option{path} is
3168 @item -chardev spicevmc,id=@var{id},debug=@var{debug},name=@var{name}
3170 @option{spicevmc} is only available when spice support is built in.
3172 @option{debug} debug level for spicevmc
3174 @option{name} name of spice channel to connect to
3176 Connect to a spice virtual machine channel, such as vdiport.
3178 @item -chardev spiceport,id=@var{id},debug=@var{debug},name=@var{name}
3180 @option{spiceport} is only available when spice support is built in.
3182 @option{debug} debug level for spicevmc
3184 @option{name} name of spice port to connect to
3186 Connect to a spice port, allowing a Spice client to handle the traffic
3187 identified by a name (preferably a fqdn).
3196 DEFHEADING(TPM device options:)
3198 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3199 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3200 " use path to provide path to a character device; default is /dev/tpm0\n"
3201 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3202 " not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3203 "-tpmdev emulator,id=id,chardev=dev\n"
3204 " configure the TPM device using chardev backend\n",
3208 The general form of a TPM device option is:
3211 @item -tpmdev @var{backend},id=@var{id}[,@var{options}]
3214 The specific backend type will determine the applicable options.
3215 The @code{-tpmdev} option creates the TPM backend and requires a
3216 @code{-device} option that specifies the TPM frontend interface model.
3218 Use @code{-tpmdev help} to print all available TPM backend types.
3222 The available backends are:
3226 @item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path}
3228 (Linux-host only) Enable access to the host's TPM using the passthrough
3231 @option{path} specifies the path to the host's TPM device, i.e., on
3232 a Linux host this would be @code{/dev/tpm0}.
3233 @option{path} is optional and by default @code{/dev/tpm0} is used.
3235 @option{cancel-path} specifies the path to the host TPM device's sysfs
3236 entry allowing for cancellation of an ongoing TPM command.
3237 @option{cancel-path} is optional and by default QEMU will search for the
3240 Some notes about using the host's TPM with the passthrough driver:
3242 The TPM device accessed by the passthrough driver must not be
3243 used by any other application on the host.
3245 Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
3246 the VM's firmware (BIOS/UEFI) will not be able to initialize the
3247 TPM again and may therefore not show a TPM-specific menu that would
3248 otherwise allow the user to configure the TPM, e.g., allow the user to
3249 enable/disable or activate/deactivate the TPM.
3250 Further, if TPM ownership is released from within a VM then the host's TPM
3251 will get disabled and deactivated. To enable and activate the
3252 TPM again afterwards, the host has to be rebooted and the user is
3253 required to enter the firmware's menu to enable and activate the TPM.
3254 If the TPM is left disabled and/or deactivated most TPM commands will fail.
3256 To create a passthrough TPM use the following two options:
3258 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3260 Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
3261 @code{tpmdev=tpm0} in the device option.
3263 @item -tpmdev emulator,id=@var{id},chardev=@var{dev}
3265 (Linux-host only) Enable access to a TPM emulator using Unix domain socket based
3268 @option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
3270 To create a TPM emulator backend device with chardev socket backend:
3273 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3286 DEFHEADING(Linux/Multiboot boot specific:)
3289 When using these options, you can use a given Linux or Multiboot
3290 kernel without installing it in the disk image. It can be useful
3291 for easier testing of various kernels.
3296 DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3297 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3299 @item -kernel @var{bzImage}
3301 Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
3302 or in multiboot format.
3305 DEF("append", HAS_ARG, QEMU_OPTION_append, \
3306 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3308 @item -append @var{cmdline}
3310 Use @var{cmdline} as kernel command line
3313 DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3314 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3316 @item -initrd @var{file}
3318 Use @var{file} as initial ram disk.
3320 @item -initrd "@var{file1} arg=foo,@var{file2}"
3322 This syntax is only available with multiboot.
3324 Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
3328 DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3329 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL)
3331 @item -dtb @var{file}
3333 Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
3342 DEFHEADING(Debug/Expert options:)
3347 DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3348 "-fw_cfg [name=]<name>,file=<file>\n"
3349 " add named fw_cfg entry with contents from file\n"
3350 "-fw_cfg [name=]<name>,string=<str>\n"
3351 " add named fw_cfg entry with contents from string\n",
3355 @item -fw_cfg [name=]@var{name},file=@var{file}
3357 Add named fw_cfg entry with contents from file @var{file}.
3359 @item -fw_cfg [name=]@var{name},string=@var{str}
3360 Add named fw_cfg entry with contents from string @var{str}.
3362 The terminating NUL character of the contents of @var{str} will not be
3363 included as part of the fw_cfg item data. To insert contents with
3364 embedded NUL characters, you have to use the @var{file} parameter.
3366 The fw_cfg entries are passed by QEMU through to the guest.
3370 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3372 creates an fw_cfg entry named opt/com.mycompany/blob with contents
3377 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3378 "-serial dev redirect the serial port to char device 'dev'\n",
3381 @item -serial @var{dev}
3383 Redirect the virtual serial port to host character device
3384 @var{dev}. The default device is @code{vc} in graphical mode and
3385 @code{stdio} in non graphical mode.
3387 This option can be used several times to simulate up to 4 serial
3390 Use @code{-serial none} to disable all serial ports.
3392 Available character devices are:
3394 @item vc[:@var{W}x@var{H}]
3395 Virtual console. Optionally, a width and height can be given in pixel with
3399 It is also possible to specify width or height in characters:
3404 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3406 No device is allocated.
3409 @item chardev:@var{id}
3410 Use a named character device defined with the @code{-chardev} option.
3412 [Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3413 parameters are set according to the emulated ones.
3414 @item /dev/parport@var{N}
3415 [Linux only, parallel port only] Use host parallel port
3416 @var{N}. Currently SPP and EPP parallel port features can be used.
3417 @item file:@var{filename}
3418 Write output to @var{filename}. No character can be read.
3420 [Unix only] standard input/output
3421 @item pipe:@var{filename}
3422 name pipe @var{filename}
3424 [Windows only] Use host serial port @var{n}
3425 @item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3426 This implements UDP Net Console.
3427 When @var{remote_host} or @var{src_ip} are not specified
3428 they default to @code{0.0.0.0}.
3429 When not using a specified @var{src_port} a random port is automatically chosen.
3431 If you just want a simple readonly console you can use @code{netcat} or
3432 @code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3433 @code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3434 will appear in the netconsole session.
3436 If you plan to send characters back via netconsole or you want to stop
3437 and start QEMU a lot of times, you should have QEMU use the same
3438 source port each time by using something like @code{-serial
3439 udp::4555@@:4556} to QEMU. Another approach is to use a patched
3440 version of netcat which can listen to a TCP port and send and receive
3441 characters via udp. If you have a patched version of netcat which
3442 activates telnet remote echo and single char transfer, then you can
3443 use the following options to set up a netcat redirector to allow
3444 telnet on port 5555 to access the QEMU port.
3447 -serial udp::4555@@:4556
3448 @item netcat options:
3449 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3450 @item telnet options:
3454 @item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3455 The TCP Net Console has two modes of operation. It can send the serial
3456 I/O to a location or wait for a connection from a location. By default
3457 the TCP Net Console is sent to @var{host} at the @var{port}. If you use
3458 the @var{server} option QEMU will wait for a client socket application
3459 to connect to the port before continuing, unless the @code{nowait}
3460 option was specified. The @code{nodelay} option disables the Nagle buffering
3461 algorithm. The @code{reconnect} option only applies if @var{noserver} is
3462 set, if the connection goes down it will attempt to reconnect at the
3463 given interval. If @var{host} is omitted, 0.0.0.0 is assumed. Only
3464 one TCP connection at a time is accepted. You can use @code{telnet} to
3465 connect to the corresponding character device.
3467 @item Example to send tcp console to 192.168.0.2 port 4444
3468 -serial tcp:192.168.0.2:4444
3469 @item Example to listen and wait on port 4444 for connection
3470 -serial tcp::4444,server
3471 @item Example to not wait and listen on ip 192.168.0.100 port 4444
3472 -serial tcp:192.168.0.100:4444,server,nowait
3475 @item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3476 The telnet protocol is used instead of raw tcp sockets. The options
3477 work the same as if you had specified @code{-serial tcp}. The
3478 difference is that the port acts like a telnet server or client using
3479 telnet option negotiation. This will also allow you to send the
3480 MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3481 sequence. Typically in unix telnet you do it with Control-] and then
3482 type "send break" followed by pressing the enter key.
3484 @item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
3485 The WebSocket protocol is used instead of raw tcp socket. The port acts as
3486 a WebSocket server. Client mode is not supported.
3488 @item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3489 A unix domain socket is used instead of a tcp socket. The option works the
3490 same as if you had specified @code{-serial tcp} except the unix domain socket
3491 @var{path} is used for connections.
3493 @item mon:@var{dev_string}
3494 This is a special option to allow the monitor to be multiplexed onto
3495 another serial port. The monitor is accessed with key sequence of
3496 @key{Control-a} and then pressing @key{c}.
3497 @var{dev_string} should be any one of the serial devices specified
3498 above. An example to multiplex the monitor onto a telnet server
3499 listening on port 4444 would be:
3501 @item -serial mon:telnet::4444,server,nowait
3503 When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3504 QEMU any more but will be passed to the guest instead.
3507 Braille device. This will use BrlAPI to display the braille output on a real
3511 Three button serial mouse. Configure the guest to use Microsoft protocol.
3515 DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3516 "-parallel dev redirect the parallel port to char device 'dev'\n",
3519 @item -parallel @var{dev}
3521 Redirect the virtual parallel port to host device @var{dev} (same
3522 devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3523 be used to use hardware devices connected on the corresponding host
3526 This option can be used several times to simulate up to 3 parallel
3529 Use @code{-parallel none} to disable all parallel ports.
3532 DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3533 "-monitor dev redirect the monitor to char device 'dev'\n",
3536 @item -monitor @var{dev}
3538 Redirect the monitor to host device @var{dev} (same devices as the
3540 The default device is @code{vc} in graphical mode and @code{stdio} in
3542 Use @code{-monitor none} to disable the default monitor.
3544 DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3545 "-qmp dev like -monitor but opens in 'control' mode\n",
3548 @item -qmp @var{dev}
3550 Like -monitor but opens in 'control' mode.
3552 DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3553 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3556 @item -qmp-pretty @var{dev}
3558 Like -qmp but uses pretty JSON formatting.
3561 DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3562 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3564 @item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]
3566 Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing
3567 easing human reading and debugging.
3570 DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3571 "-debugcon dev redirect the debug console to char device 'dev'\n",
3574 @item -debugcon @var{dev}
3576 Redirect the debug console to host device @var{dev} (same devices as the
3577 serial port). The debug console is an I/O port which is typically port
3578 0xe9; writing to that I/O port sends output to this device.
3579 The default device is @code{vc} in graphical mode and @code{stdio} in
3583 DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3584 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL)
3586 @item -pidfile @var{file}
3588 Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3592 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3593 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL)
3597 Run the emulation in single step mode.
3600 DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3601 "--preconfig pause QEMU before machine is initialized (experimental)\n",
3606 Pause QEMU for interactive configuration before the machine is created,
3607 which allows querying and configuring properties that will affect
3608 machine initialization. Use QMP command 'x-exit-preconfig' to exit
3609 the preconfig state and move to the next state (i.e. run guest if -S
3610 isn't used or pause the second time if -S is used). This option is
3614 DEF("S", 0, QEMU_OPTION_S, \
3615 "-S freeze CPU at startup (use 'c' to start execution)\n",
3620 Do not start CPU at startup (you must type 'c' in the monitor).
3623 DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
3624 "-realtime [mlock=on|off]\n"
3625 " run qemu with realtime features\n"
3626 " mlock=on|off controls mlock support (default: on)\n",
3629 @item -realtime mlock=on|off
3631 Run qemu with realtime features.
3632 mlocking qemu and guest memory can be enabled via @option{mlock=on}
3633 (enabled by default).
3636 DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3637 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3638 " run qemu with overcommit hints\n"
3639 " mem-lock=on|off controls memory lock support (default: off)\n"
3640 " cpu-pm=on|off controls cpu power management (default: off)\n",
3643 @item -overcommit mem-lock=on|off
3644 @item -overcommit cpu-pm=on|off
3646 Run qemu with hints about host resource overcommit. The default is
3647 to assume that host overcommits all resources.
3649 Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3650 by default). This works when host memory is not overcommitted and reduces the
3651 worst-case latency for guest. This is equivalent to @option{realtime}.
3653 Guest ability to manage power state of host cpus (increasing latency for other
3654 processes on the same host cpu, but decreasing latency for guest) can be
3655 enabled via @option{cpu-pm=on} (disabled by default). This works best when
3656 host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3657 utilization will be incorrect, not taking into account guest idle time.
3660 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3661 "-gdb dev wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
3663 @item -gdb @var{dev}
3665 Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3666 connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3667 stdio are reasonable use case. The latter is allowing to start QEMU from
3668 within gdb and establish the connection via a pipe:
3670 (gdb) target remote | exec @value{qemu_system} -gdb stdio ...
3674 DEF("s", 0, QEMU_OPTION_s, \
3675 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3680 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3681 (@pxref{gdb_usage}).
3684 DEF("d", HAS_ARG, QEMU_OPTION_d, \
3685 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n",
3688 @item -d @var{item1}[,...]
3690 Enable logging of specified items. Use '-d help' for a list of log items.
3693 DEF("D", HAS_ARG, QEMU_OPTION_D, \
3694 "-D logfile output log to logfile (default stderr)\n",
3697 @item -D @var{logfile}
3699 Output log in @var{logfile} instead of to stderr
3702 DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3703 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3706 @item -dfilter @var{range1}[,...]
3708 Filter debug output to that relevant to a range of target addresses. The filter
3709 spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3710 @var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3711 addresses and sizes required. For example:
3713 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3715 Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3716 the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3717 block starting at 0xffffffc00005f000.
3720 DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
3721 "-seed number seed the pseudo-random number generator\n",
3724 @item -seed @var{number}
3726 Force the guest to use a deterministic pseudo-random number generator, seeded
3727 with @var{number}. This does not affect crypto routines within the host.
3730 DEF("L", HAS_ARG, QEMU_OPTION_L, \
3731 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
3736 Set the directory for the BIOS, VGA BIOS and keymaps.
3738 To list all the data directories, use @code{-L help}.
3741 DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3742 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL)
3744 @item -bios @var{file}
3746 Set the filename for the BIOS.
3749 DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3750 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3754 Enable KVM full virtualization support. This option is only available
3755 if KVM support is enabled when compiling.
3758 DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3759 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL)
3760 DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3761 "-xen-attach attach to existing xen domain\n"
3762 " libxl will use this when starting QEMU\n",
3764 DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3765 "-xen-domid-restrict restrict set of available xen operations\n"
3766 " to specified domain id. (Does not affect\n"
3767 " xenpv machine type).\n",
3770 @item -xen-domid @var{id}
3772 Specify xen guest domain @var{id} (XEN only).
3775 Attach to existing xen domain.
3776 libxl will use this when starting QEMU (XEN only).
3777 @findex -xen-domid-restrict
3778 Restrict set of available xen operations to specified domain id (XEN only).
3781 DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3782 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL)
3786 Exit instead of rebooting.
3789 DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3790 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL)
3793 @findex -no-shutdown
3794 Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3795 This allows for instance switching to monitor to commit changes to the
3799 DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
3800 "-loadvm [tag|id]\n" \
3801 " start right away with a saved state (loadvm in monitor)\n",
3804 @item -loadvm @var{file}
3806 Start right away with a saved state (@code{loadvm} in monitor)
3810 DEF("daemonize", 0, QEMU_OPTION_daemonize, \
3811 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
3816 Daemonize the QEMU process after initialization. QEMU will not detach from
3817 standard IO until it is ready to receive connections on any of its devices.
3818 This option is a useful way for external programs to launch QEMU without having
3819 to cope with initialization race conditions.
3822 DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
3823 "-option-rom rom load a file, rom, into the option ROM space\n",
3826 @item -option-rom @var{file}
3828 Load the contents of @var{file} as an option ROM.
3829 This option is useful to load things like EtherBoot.
3832 DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
3833 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
3834 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
3839 @item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew]
3841 Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3842 UTC or local time, respectively. @code{localtime} is required for correct date in
3843 MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the
3844 format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3846 By default the RTC is driven by the host system time. This allows using of the
3847 RTC as accurate reference clock inside the guest, specifically if the host
3848 time is smoothly following an accurate external reference clock, e.g. via NTP.
3849 If you want to isolate the guest time from the host, you can set @option{clock}
3850 to @code{rt} instead, which provides a host monotonic clock if host support it.
3851 To even prevent the RTC from progressing during suspension, you can set @option{clock}
3852 to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in
3853 icount mode in order to preserve determinism; however, note that in icount mode
3854 the speed of the virtual clock is variable and can in general differ from the
3857 Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3858 specifically with Windows' ACPI HAL. This option will try to figure out how
3859 many timer interrupts were not processed by the Windows guest and will
3863 DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
3864 "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \
3865 " enable virtual instruction counter with 2^N clock ticks per\n" \
3866 " instruction, enable aligning the host and virtual clocks\n" \
3867 " or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
3869 @item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3871 Enable virtual instruction counter. The virtual cpu will execute one
3872 instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified
3873 then the virtual cpu speed will be automatically adjusted to keep virtual
3874 time within a few seconds of real time.
3876 When the virtual cpu is sleeping, the virtual time will advance at default
3877 speed unless @option{sleep=on|off} is specified.
3878 With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3879 instantly whenever the virtual cpu goes to sleep mode and will not advance
3880 if no timer is enabled. This behavior give deterministic execution times from
3881 the guest point of view.
3883 Note that while this option can give deterministic behavior, it does not
3884 provide cycle accurate emulation. Modern CPUs contain superscalar out of
3885 order cores with complex cache hierarchies. The number of instructions
3886 executed often has little or no correlation with actual performance.
3888 @option{align=on} will activate the delay algorithm which will try
3889 to synchronise the host clock and the virtual clock. The goal is to
3890 have a guest running at the real frequency imposed by the shift option.
3891 Whenever the guest clock is behind the host clock and if
3892 @option{align=on} is specified then we print a message to the user
3893 to inform about the delay.
3894 Currently this option does not work when @option{shift} is @code{auto}.
3895 Note: The sync algorithm will work for those shift values for which
3896 the guest clock runs ahead of the host clock. Typically this happens
3897 when the shift value is high (how high depends on the host machine).
3899 When @option{rr} option is specified deterministic record/replay is enabled.
3900 Replay log is written into @var{filename} file in record mode and
3901 read from this file in replay mode.
3903 Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3904 at the start of execution recording. In replay mode this option is used
3905 to load the initial VM state.
3908 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
3909 "-watchdog model\n" \
3910 " enable virtual hardware watchdog [default=none]\n",
3913 @item -watchdog @var{model}
3915 Create a virtual hardware watchdog device. Once enabled (by a guest
3916 action), the watchdog must be periodically polled by an agent inside
3917 the guest or else the guest will be restarted. Choose a model for
3918 which your guest has drivers.
3920 The @var{model} is the model of hardware watchdog to emulate. Use
3921 @code{-watchdog help} to list available hardware models. Only one
3922 watchdog can be enabled for a guest.
3924 The following models may be available:
3927 iBASE 700 is a very simple ISA watchdog with a single timer.
3929 Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3930 dual-timer watchdog.
3932 A virtual watchdog for s390x backed by the diagnose 288 hypercall
3933 (currently KVM only).
3937 DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
3938 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
3939 " action when watchdog fires [default=reset]\n",
3942 @item -watchdog-action @var{action}
3943 @findex -watchdog-action
3945 The @var{action} controls what QEMU will do when the watchdog timer
3948 @code{reset} (forcefully reset the guest).
3949 Other possible actions are:
3950 @code{shutdown} (attempt to gracefully shutdown the guest),
3951 @code{poweroff} (forcefully poweroff the guest),
3952 @code{inject-nmi} (inject a NMI into the guest),
3953 @code{pause} (pause the guest),
3954 @code{debug} (print a debug message and continue), or
3955 @code{none} (do nothing).
3957 Note that the @code{shutdown} action requires that the guest responds
3958 to ACPI signals, which it may not be able to do in the sort of
3959 situations where the watchdog would have expired, and thus
3960 @code{-watchdog-action shutdown} is not recommended for production use.
3965 @item -watchdog i6300esb -watchdog-action pause
3966 @itemx -watchdog ib700
3970 DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
3971 "-echr chr set terminal escape character instead of ctrl-a\n",
3975 @item -echr @var{numeric_ascii_value}
3977 Change the escape character used for switching to the monitor when using
3978 monitor and serial sharing. The default is @code{0x01} when using the
3979 @code{-nographic} option. @code{0x01} is equal to pressing
3980 @code{Control-a}. You can select a different character from the ascii
3981 control keys where 1 through 26 map to Control-a through Control-z. For
3982 instance you could use the either of the following to change the escape
3983 character to Control-t.
3990 DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
3991 "-show-cursor show cursor\n", QEMU_ARCH_ALL)
3994 @findex -show-cursor
3998 DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
3999 "-tb-size n set TB size\n", QEMU_ARCH_ALL)
4001 @item -tb-size @var{n}
4003 Set TCG translation block cache size. Deprecated, use @samp{-accel tcg,tb-size=@var{n}}
4007 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
4008 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \
4009 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \
4010 "-incoming unix:socketpath\n" \
4011 " prepare for incoming migration, listen on\n" \
4012 " specified protocol and socket address\n" \
4013 "-incoming fd:fd\n" \
4014 "-incoming exec:cmdline\n" \
4015 " accept incoming migration on given file descriptor\n" \
4016 " or from given external command\n" \
4017 "-incoming defer\n" \
4018 " wait for the URI to be specified via migrate_incoming\n",
4021 @item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
4022 @itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
4024 Prepare for incoming migration, listen on a given tcp port.
4026 @item -incoming unix:@var{socketpath}
4027 Prepare for incoming migration, listen on a given unix socket.
4029 @item -incoming fd:@var{fd}
4030 Accept incoming migration from a given filedescriptor.
4032 @item -incoming exec:@var{cmdline}
4033 Accept incoming migration as an output from specified external command.
4035 @item -incoming defer
4036 Wait for the URI to be specified via migrate_incoming. The monitor can
4037 be used to change settings (such as migration parameters) prior to issuing
4038 the migrate_incoming to allow the migration to begin.
4041 DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
4042 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL)
4044 @item -only-migratable
4045 @findex -only-migratable
4046 Only allow migratable devices. Devices will not be allowed to enter an
4050 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
4051 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL)
4055 Don't create default devices. Normally, QEMU sets the default devices like serial
4056 port, parallel port, virtual console, monitor device, VGA adapter, floppy and
4057 CD-ROM drive and others. The @code{-nodefaults} option will disable all those
4062 DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
4063 "-chroot dir chroot to dir just before starting the VM\n",
4067 @item -chroot @var{dir}
4069 Immediately before starting guest execution, chroot to the specified
4070 directory. Especially useful in combination with -runas.
4074 DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4075 "-runas user change to user id user just before starting the VM\n" \
4076 " user can be numeric uid:gid instead\n",
4080 @item -runas @var{user}
4082 Immediately before starting guest execution, drop root privileges, switching
4083 to the specified user.
4086 DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4087 "-prom-env variable=value\n"
4088 " set OpenBIOS nvram variables\n",
4089 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4091 @item -prom-env @var{variable}=@var{value}
4093 Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
4095 DEF("semihosting", 0, QEMU_OPTION_semihosting,
4096 "-semihosting semihosting mode\n",
4097 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4098 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4101 @findex -semihosting
4102 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
4104 DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4105 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
4106 " semihosting configuration\n",
4107 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4108 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4110 @item -semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]
4111 @findex -semihosting-config
4112 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only).
4114 @item target=@code{native|gdb|auto}
4115 Defines where the semihosting calls will be addressed, to QEMU (@code{native})
4116 or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
4117 during debug sessions and @code{native} otherwise.
4118 @item chardev=@var{str1}
4119 Send the output to a chardev backend output for native or auto output when not in gdb
4120 @item arg=@var{str1},arg=@var{str2},...
4121 Allows the user to pass input arguments, and can be used multiple times to build
4122 up a list. The old-style @code{-kernel}/@code{-append} method of passing a
4123 command line is still supported for backward compatibility. If both the
4124 @code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
4125 specified, the former is passed to semihosting as it always takes precedence.
4128 DEF("old-param", 0, QEMU_OPTION_old_param,
4129 "-old-param old param mode\n", QEMU_ARCH_ARM)
4132 @findex -old-param (ARM)
4133 Old param mode (ARM only).
4136 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4137 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4138 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4139 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4140 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4141 " by the kernel, but typically no longer used by modern\n" \
4142 " C library implementations.\n" \
4143 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
4144 " its privileges by blacklisting all set*uid|gid system calls.\n" \
4145 " The value 'children' will deny set*uid|gid system calls for\n" \
4146 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4147 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4148 " blacklisting *fork and execve\n" \
4149 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4152 @item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
4154 Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
4155 disable it. The default is 'off'.
4157 @item obsolete=@var{string}
4158 Enable Obsolete system calls
4159 @item elevateprivileges=@var{string}
4160 Disable set*uid|gid system calls
4161 @item spawn=@var{string}
4162 Disable *fork and execve
4163 @item resourcecontrol=@var{string}
4164 Disable process affinity and schedular priority
4168 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4169 "-readconfig <file>\n", QEMU_ARCH_ALL)
4171 @item -readconfig @var{file}
4173 Read device configuration from @var{file}. This approach is useful when you want to spawn
4174 QEMU process with many command line options but you don't want to exceed the command line
4177 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
4178 "-writeconfig <file>\n"
4179 " read/write config file\n", QEMU_ARCH_ALL)
4181 @item -writeconfig @var{file}
4182 @findex -writeconfig
4183 Write device configuration to @var{file}. The @var{file} can be either filename to save
4184 command line and device configuration into file or dash @code{-}) character to print the
4185 output to stdout. This can be later used as input file for @code{-readconfig} option.
4188 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4190 " do not load default user-provided config files at startup\n",
4193 @item -no-user-config
4194 @findex -no-user-config
4195 The @code{-no-user-config} option makes QEMU not load any of the user-provided
4196 config files on @var{sysconfdir}.
4199 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4200 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4201 " specify tracing options\n",
4204 HXCOMM This line is not accurate, as some sub-options are backend-specific but
4205 HXCOMM HX does not support conditional compilation of text.
4206 @item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
4208 @include qemu-option-trace.texi
4210 DEF("plugin", HAS_ARG, QEMU_OPTION_plugin,
4211 "-plugin [file=]<file>[,arg=<string>]\n"
4215 @item -plugin file=@var{file}[,arg=@var{string}]
4221 @item file=@var{file}
4222 Load the given plugin from a shared library file.
4223 @item arg=@var{string}
4224 Argument string passed to the plugin. (Can be given multiple times.)
4229 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4230 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4233 DEF("enable-fips", 0, QEMU_OPTION_enablefips,
4234 "-enable-fips enable FIPS 140-2 compliance\n",
4239 @findex -enable-fips
4240 Enable FIPS 140-2 compliance mode.
4243 HXCOMM Deprecated by -accel tcg
4244 DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
4246 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4247 "-msg timestamp[=on|off]\n"
4248 " control error message format\n"
4249 " timestamp=on enables timestamps (default: off)\n",
4252 @item -msg timestamp[=on|off]
4254 Control error message format.
4256 @item timestamp=on|off
4257 Prefix messages with a timestamp. Default is off.
4261 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4262 "-dump-vmstate <file>\n"
4263 " Output vmstate information in JSON format to file.\n"
4264 " Use the scripts/vmstate-static-checker.py file to\n"
4265 " check for possible regressions in migration code\n"
4266 " by comparing two such vmstate dumps.\n",
4269 @item -dump-vmstate @var{file}
4270 @findex -dump-vmstate
4271 Dump json-encoded vmstate information for current machine type to file
4275 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4276 "-enable-sync-profile\n"
4277 " enable synchronization profiling\n",
4280 @item -enable-sync-profile
4281 @findex -enable-sync-profile
4282 Enable synchronization profiling.
4290 DEFHEADING(Generic object creation:)
4295 DEF("object", HAS_ARG, QEMU_OPTION_object,
4296 "-object TYPENAME[,PROP1=VALUE1,...]\n"
4297 " create a new object of type TYPENAME setting properties\n"
4298 " in the order they are specified. Note that the 'id'\n"
4299 " property must be set. These objects are placed in the\n"
4300 " '/objects' path.\n",
4303 @item -object @var{typename}[,@var{prop1}=@var{value1},...]
4305 Create a new object of type @var{typename} setting properties
4306 in the order they are specified. Note that the 'id'
4307 property must be set. These objects are placed in the
4312 @item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},align=@var{align}
4314 Creates a memory file backend object, which can be used to back
4315 the guest RAM with huge pages.
4317 The @option{id} parameter is a unique ID that will be used to reference this
4318 memory region when configuring the @option{-numa} argument.
4320 The @option{size} option provides the size of the memory region, and accepts
4321 common suffixes, eg @option{500M}.
4323 The @option{mem-path} provides the path to either a shared memory or huge page
4326 The @option{share} boolean option determines whether the memory
4327 region is marked as private to QEMU, or shared. The latter allows
4328 a co-operating external process to access the QEMU memory region.
4330 The @option{share} is also required for pvrdma devices due to
4331 limitations in the RDMA API provided by Linux.
4333 Setting share=on might affect the ability to configure NUMA
4334 bindings for the memory backend under some circumstances, see
4335 Documentation/vm/numa_memory_policy.txt on the Linux kernel
4336 source tree for additional details.
4338 Setting the @option{discard-data} boolean option to @var{on}
4339 indicates that file contents can be destroyed when QEMU exits,
4340 to avoid unnecessarily flushing data to the backing file. Note
4341 that @option{discard-data} is only an optimization, and QEMU
4342 might not discard file contents if it aborts unexpectedly or is
4343 terminated using SIGKILL.
4345 The @option{merge} boolean option enables memory merge, also known as
4346 MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
4347 memory deduplication.
4349 Setting the @option{dump} boolean option to @var{off} excludes the memory from
4350 core dumps. This feature is also known as MADV_DONTDUMP.
4352 The @option{prealloc} boolean option enables memory preallocation.
4354 The @option{host-nodes} option binds the memory range to a list of NUMA host
4357 The @option{policy} option sets the NUMA policy to one of the following values:
4363 @item @var{preferred}
4364 prefer the given host node list for allocation
4367 restrict memory allocation to the given host node list
4369 @item @var{interleave}
4370 interleave memory allocations across the given host node list
4373 The @option{align} option specifies the base address alignment when
4374 QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4375 @option{2M}. Some backend store specified by @option{mem-path}
4376 requires an alignment different than the default one used by QEMU, eg
4377 the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4378 such cases, users can specify the required alignment via this option.
4380 The @option{pmem} option specifies whether the backing file specified
4381 by @option{mem-path} is in host persistent memory that can be accessed
4382 using the SNIA NVM programming model (e.g. Intel NVDIMM).
4383 If @option{pmem} is set to 'on', QEMU will take necessary operations to
4384 guarantee the persistence of its own writes to @option{mem-path}
4385 (e.g. in vNVDIMM label emulation and live migration).
4386 Also, we will map the backend-file with MAP_SYNC flag, which ensures the
4387 file metadata is in sync for @option{mem-path} in case of host crash
4388 or a power failure. MAP_SYNC requires support from both the host kernel
4389 (since Linux kernel 4.15) and the filesystem of @option{mem-path} mounted
4392 @item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave}
4394 Creates a memory backend object, which can be used to back the guest RAM.
4395 Memory backend objects offer more control than the @option{-m} option that is
4396 traditionally used to define guest RAM. Please refer to
4397 @option{memory-backend-file} for a description of the options.
4399 @item -object memory-backend-memfd,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},seal=@var{on|off},hugetlb=@var{on|off},hugetlbsize=@var{size}
4401 Creates an anonymous memory file backend object, which allows QEMU to
4402 share the memory with an external process (e.g. when using
4403 vhost-user). The memory is allocated with memfd and optional
4404 sealing. (Linux only)
4406 The @option{seal} option creates a sealed-file, that will block
4407 further resizing the memory ('on' by default).
4409 The @option{hugetlb} option specify the file to be created resides in
4410 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction with
4411 the @option{hugetlb} option, the @option{hugetlbsize} option specify
4412 the hugetlb page size on systems that support multiple hugetlb page
4413 sizes (it must be a power of 2 value supported by the system).
4415 In some versions of Linux, the @option{hugetlb} option is incompatible
4416 with the @option{seal} option (requires at least Linux 4.16).
4418 Please refer to @option{memory-backend-file} for a description of the
4421 The @option{share} boolean option is @var{on} by default with memfd.
4423 @item -object rng-builtin,id=@var{id}
4425 Creates a random number generator backend which obtains entropy from
4426 QEMU builtin functions. The @option{id} parameter is a unique ID that
4427 will be used to reference this entropy backend from the @option{virtio-rng}
4428 device. By default, the @option{virtio-rng} device uses this RNG backend.
4430 @item -object rng-random,id=@var{id},filename=@var{/dev/random}
4432 Creates a random number generator backend which obtains entropy from
4433 a device on the host. The @option{id} parameter is a unique ID that
4434 will be used to reference this entropy backend from the @option{virtio-rng}
4435 device. The @option{filename} parameter specifies which file to obtain
4436 entropy from and if omitted defaults to @option{/dev/urandom}.
4438 @item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4440 Creates a random number generator backend which obtains entropy from
4441 an external daemon running on the host. The @option{id} parameter is
4442 a unique ID that will be used to reference this entropy backend from
4443 the @option{virtio-rng} device. The @option{chardev} parameter is
4444 the unique ID of a character device backend that provides the connection
4447 @item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4449 Creates a TLS anonymous credentials object, which can be used to provide
4450 TLS support on network backends. The @option{id} parameter is a unique
4451 ID which network backends will use to access the credentials. The
4452 @option{endpoint} is either @option{server} or @option{client} depending
4453 on whether the QEMU network backend that uses the credentials will be
4454 acting as a client or as a server. If @option{verify-peer} is enabled
4455 (the default) then once the handshake is completed, the peer credentials
4456 will be verified, though this is a no-op for anonymous credentials.
4458 The @var{dir} parameter tells QEMU where to find the credential
4459 files. For server endpoints, this directory may contain a file
4460 @var{dh-params.pem} providing diffie-hellman parameters to use
4461 for the TLS server. If the file is missing, QEMU will generate
4462 a set of DH parameters at startup. This is a computationally
4463 expensive operation that consumes random pool entropy, so it is
4464 recommended that a persistent set of parameters be generated
4467 @item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4469 Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4470 TLS support on network backends. The @option{id} parameter is a unique
4471 ID which network backends will use to access the credentials. The
4472 @option{endpoint} is either @option{server} or @option{client} depending
4473 on whether the QEMU network backend that uses the credentials will be
4474 acting as a client or as a server. For clients only, @option{username}
4475 is the username which will be sent to the server. If omitted
4476 it defaults to ``qemu''.
4478 The @var{dir} parameter tells QEMU where to find the keys file.
4479 It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4480 pairs. This file can most easily be created using the GnuTLS
4481 @code{psktool} program.
4483 For server endpoints, @var{dir} may also contain a file
4484 @var{dh-params.pem} providing diffie-hellman parameters to use
4485 for the TLS server. If the file is missing, QEMU will generate
4486 a set of DH parameters at startup. This is a computationally
4487 expensive operation that consumes random pool entropy, so it is
4488 recommended that a persistent set of parameters be generated
4491 @item -object tls-creds-x509,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},priority=@var{priority},verify-peer=@var{on|off},passwordid=@var{id}
4493 Creates a TLS anonymous credentials object, which can be used to provide
4494 TLS support on network backends. The @option{id} parameter is a unique
4495 ID which network backends will use to access the credentials. The
4496 @option{endpoint} is either @option{server} or @option{client} depending
4497 on whether the QEMU network backend that uses the credentials will be
4498 acting as a client or as a server. If @option{verify-peer} is enabled
4499 (the default) then once the handshake is completed, the peer credentials
4500 will be verified. With x509 certificates, this implies that the clients
4501 must be provided with valid client certificates too.
4503 The @var{dir} parameter tells QEMU where to find the credential
4504 files. For server endpoints, this directory may contain a file
4505 @var{dh-params.pem} providing diffie-hellman parameters to use
4506 for the TLS server. If the file is missing, QEMU will generate
4507 a set of DH parameters at startup. This is a computationally
4508 expensive operation that consumes random pool entropy, so it is
4509 recommended that a persistent set of parameters be generated
4512 For x509 certificate credentials the directory will contain further files
4513 providing the x509 certificates. The certificates must be stored
4514 in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4515 @var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4516 @var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4518 For the @var{server-key.pem} and @var{client-key.pem} files which
4519 contain sensitive private keys, it is possible to use an encrypted
4520 version by providing the @var{passwordid} parameter. This provides
4521 the ID of a previously created @code{secret} object containing the
4522 password for decryption.
4524 The @var{priority} parameter allows to override the global default
4525 priority used by gnutls. This can be useful if the system administrator
4526 needs to use a weaker set of crypto priorities for QEMU without
4527 potentially forcing the weakness onto all applications. Or conversely
4528 if one wants wants a stronger default for QEMU than for all other
4529 applications, they can do this through this parameter. Its format is
4530 a gnutls priority string as described at
4531 @url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4533 @item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4535 Interval @var{t} can't be 0, this filter batches the packet delivery: all
4536 packets arriving in a given interval on netdev @var{netdevid} are delayed
4537 until the end of the interval. Interval is in microseconds.
4538 @option{status} is optional that indicate whether the netfilter is
4539 on (enabled) or off (disabled), the default status for netfilter will be 'on'.
4541 queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4543 @option{all}: the filter is attached both to the receive and the transmit
4544 queue of the netdev (default).
4546 @option{rx}: the filter is attached to the receive queue of the netdev,
4547 where it will receive packets sent to the netdev.
4549 @option{tx}: the filter is attached to the transmit queue of the netdev,
4550 where it will receive packets sent by the netdev.
4552 @item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4554 filter-mirror on netdev @var{netdevid},mirror net packet to chardev@var{chardevid}, if it has the vnet_hdr_support flag, filter-mirror will mirror packet with vnet_hdr_len.
4556 @item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4558 filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4559 @var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag,
4560 filter-redirector will redirect packet with vnet_hdr_len.
4561 Create a filter-redirector we need to differ outdev id from indev id, id can not
4562 be the same. we can just use indev or outdev, but at least one of indev or outdev
4563 need to be specified.
4565 @item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support]
4567 Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4568 secondary from primary to keep secondary tcp connection,and rewrite
4569 tcp packet to primary from secondary make tcp packet can be handled by
4570 client.if it has the vnet_hdr_support flag, we can parse packet with vnet header.
4574 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4575 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4576 -object filter-rewriter,id=rew0,netdev=hn0,queue=all
4578 @item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4580 Dump the network traffic on netdev @var{dev} to the file specified by
4581 @var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4582 The file format is libpcap, so it can be analyzed with tools such as tcpdump
4585 @item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},outdev=@var{chardevid},iothread=@var{id}[,vnet_hdr_support][,notify_dev=@var{id}]
4587 Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4588 secondary packet. If the packets are same, we will output primary
4589 packet to outdev@var{chardevid}, else we will notify colo-frame
4590 do checkpoint and send primary packet to outdev@var{chardevid}.
4591 In order to improve efficiency, we need to put the task of comparison
4592 in another thread. If it has the vnet_hdr_support flag, colo compare
4593 will send/recv packet with vnet_hdr_len.
4594 If you want to use Xen COLO, will need the notify_dev to notify Xen
4595 colo-frame to do checkpoint.
4597 we must use it with the help of filter-mirror and filter-redirector.
4604 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4605 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4606 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4607 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4608 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4609 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4610 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4611 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4612 -object iothread,id=iothread1
4613 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4614 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4615 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4616 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
4619 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4620 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4621 -chardev socket,id=red0,host=3.3.3.3,port=9003
4622 -chardev socket,id=red1,host=3.3.3.3,port=9004
4623 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4624 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4630 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4631 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4632 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4633 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4634 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4635 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4636 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4637 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4638 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait
4639 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4640 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4641 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4642 -object iothread,id=iothread1
4643 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
4646 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4647 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4648 -chardev socket,id=red0,host=3.3.3.3,port=9003
4649 -chardev socket,id=red1,host=3.3.3.3,port=9004
4650 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4651 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4655 If you want to know the detail of above command line, you can read
4656 the colo-compare git log.
4658 @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4660 Creates a cryptodev backend which executes crypto opreation from
4661 the QEMU cipher APIS. The @var{id} parameter is
4662 a unique ID that will be used to reference this cryptodev backend from
4663 the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4664 which specify the queue number of cryptodev backend, the default of
4669 # @value{qemu_system} \
4671 -object cryptodev-backend-builtin,id=cryptodev0 \
4672 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4676 @item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}]
4678 Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}.
4679 The @var{id} parameter is a unique ID that will be used to reference this
4680 cryptodev backend from the @option{virtio-crypto} device.
4681 The chardev should be a unix domain socket backed one. The vhost-user uses
4682 a specifically defined protocol to pass vhost ioctl replacement messages
4683 to an application on the other end of the socket.
4684 The @var{queues} parameter is optional, which specify the queue number
4685 of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1.
4689 # @value{qemu_system} \
4691 -chardev socket,id=chardev0,path=/path/to/socket \
4692 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \
4693 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4697 @item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4698 @item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4700 Defines a secret to store a password, encryption key, or some other sensitive
4701 data. The sensitive data can either be passed directly via the @var{data}
4702 parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4703 parameter is insecure unless the sensitive data is encrypted.
4705 The sensitive data can be provided in raw format (the default), or base64.
4706 When encoded as JSON, the raw format only supports valid UTF-8 characters,
4707 so base64 is recommended for sending binary data. QEMU will convert from
4708 which ever format is provided to the format it needs internally. eg, an
4709 RBD password can be provided in raw format, even though it will be base64
4710 encoded when passed onto the RBD sever.
4712 For added protection, it is possible to encrypt the data associated with
4713 a secret using the AES-256-CBC cipher. Use of encryption is indicated
4714 by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4715 parameter provides the ID of a previously defined secret that contains
4716 the AES-256 decryption key. This key should be 32-bytes long and be
4717 base64 encoded. The @var{iv} parameter provides the random initialization
4718 vector used for encryption of this particular secret and should be a
4719 base64 encrypted string of the 16-byte IV.
4721 The simplest (insecure) usage is to provide the secret inline
4725 # @value{qemu_system} -object secret,id=sec0,data=letmein,format=raw
4729 The simplest secure usage is to provide the secret via a file
4731 # printf "letmein" > mypasswd.txt
4732 # @value{qemu_system} -object secret,id=sec0,file=mypasswd.txt,format=raw
4734 For greater security, AES-256-CBC should be used. To illustrate usage,
4735 consider the openssl command line tool which can encrypt the data. Note
4736 that when encrypting, the plaintext must be padded to the cipher block
4737 size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4739 First a master key needs to be created in base64 encoding:
4742 # openssl rand -base64 32 > key.b64
4743 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
4746 Each secret to be encrypted needs to have a random initialization vector
4747 generated. These do not need to be kept secret
4750 # openssl rand -base64 16 > iv.b64
4751 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
4754 The secret to be defined can now be encrypted, in this case we're
4755 telling openssl to base64 encode the result, but it could be left
4756 as raw bytes if desired.
4759 # SECRET=$(printf "letmein" |
4760 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4763 When launching QEMU, create a master secret pointing to @code{key.b64}
4764 and specify that to be used to decrypt the user password. Pass the
4765 contents of @code{iv.b64} to the second secret
4768 # @value{qemu_system} \
4769 -object secret,id=secmaster0,format=base64,file=key.b64 \
4770 -object secret,id=sec0,keyid=secmaster0,format=base64,\
4771 data=$SECRET,iv=$(<iv.b64)
4774 @item -object sev-guest,id=@var{id},cbitpos=@var{cbitpos},reduced-phys-bits=@var{val},[sev-device=@var{string},policy=@var{policy},handle=@var{handle},dh-cert-file=@var{file},session-file=@var{file}]
4776 Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4777 to provide the guest memory encryption support on AMD processors.
4779 When memory encryption is enabled, one of the physical address bit (aka the
4780 C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4781 is used to provide the C-bit position. The C-bit position is Host family dependent
4782 hence user must provide this value. On EPYC, the value should be 47.
4784 When memory encryption is enabled, we loose certain bits in physical address space.
4785 The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4786 physical address space. Similar to C-bit, the value is Host family dependent.
4787 On EPYC, the value should be 5.
4789 The @option{sev-device} provides the device file to use for communicating with
4790 the SEV firmware running inside AMD Secure Processor. The default device is
4791 '/dev/sev'. If hardware supports memory encryption then /dev/sev devices are
4792 created by CCP driver.
4794 The @option{policy} provides the guest policy to be enforced by the SEV firmware
4795 and restrict what configuration and operational commands can be performed on this
4796 guest by the hypervisor. The policy should be provided by the guest owner and is
4797 bound to the guest and cannot be changed throughout the lifetime of the guest.
4800 If guest @option{policy} allows sharing the key with another SEV guest then
4801 @option{handle} can be use to provide handle of the guest from which to share
4804 The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4805 Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters
4806 are used for establishing a cryptographic session with the guest owner to
4807 negotiate keys used for attestation. The file must be encoded in base64.
4809 e.g to launch a SEV guest
4811 # @value{qemu_system_x86} \
4813 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
4814 -machine ...,memory-encryption=sev0
4820 @item -object authz-simple,id=@var{id},identity=@var{string}
4822 Create an authorization object that will control access to network services.
4824 The @option{identity} parameter is identifies the user and its format
4825 depends on the network service that authorization object is associated
4826 with. For authorizing based on TLS x509 certificates, the identity must
4827 be the x509 distinguished name. Note that care must be taken to escape
4828 any commas in the distinguished name.
4830 An example authorization object to validate a x509 distinguished name
4833 # @value{qemu_system} \
4835 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \
4839 Note the use of quotes due to the x509 distinguished name containing
4840 whitespace, and escaping of ','.
4842 @item -object authz-listfile,id=@var{id},filename=@var{path},refresh=@var{yes|no}
4844 Create an authorization object that will control access to network services.
4846 The @option{filename} parameter is the fully qualified path to a file
4847 containing the access control list rules in JSON format.
4849 An example set of rules that match against SASL usernames might look
4855 @{ "match": "fred", "policy": "allow", "format": "exact" @},
4856 @{ "match": "bob", "policy": "allow", "format": "exact" @},
4857 @{ "match": "danb", "policy": "deny", "format": "glob" @},
4858 @{ "match": "dan*", "policy": "allow", "format": "exact" @},
4864 When checking access the object will iterate over all the rules and
4865 the first rule to match will have its @option{policy} value returned
4866 as the result. If no rules match, then the default @option{policy}
4869 The rules can either be an exact string match, or they can use the
4870 simple UNIX glob pattern matching to allow wildcards to be used.
4872 If @option{refresh} is set to true the file will be monitored
4873 and automatically reloaded whenever its content changes.
4875 As with the @code{authz-simple} object, the format of the identity
4876 strings being matched depends on the network service, but is usually
4877 a TLS x509 distinguished name, or a SASL username.
4879 An example authorization object to validate a SASL username
4882 # @value{qemu_system} \
4884 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes
4888 @item -object authz-pam,id=@var{id},service=@var{string}
4890 Create an authorization object that will control access to network services.
4892 The @option{service} parameter provides the name of a PAM service to use
4893 for authorization. It requires that a file @code{/etc/pam.d/@var{service}}
4894 exist to provide the configuration for the @code{account} subsystem.
4896 An example authorization object to validate a TLS x509 distinguished
4897 name would look like:
4900 # @value{qemu_system} \
4902 -object authz-pam,id=auth0,service=qemu-vnc
4906 There would then be a corresponding config file for PAM at
4907 @code{/etc/pam.d/qemu-vnc} that contains:
4910 account requisite pam_listfile.so item=user sense=allow \
4911 file=/etc/qemu/vnc.allow
4914 Finally the @code{/etc/qemu/vnc.allow} file would contain
4915 the list of x509 distingished names that are permitted
4919 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
4922 @item -object iothread,id=@var{id},poll-max-ns=@var{poll-max-ns},poll-grow=@var{poll-grow},poll-shrink=@var{poll-shrink}
4924 Creates a dedicated event loop thread that devices can be assigned to. This is
4925 known as an IOThread. By default device emulation happens in vCPU threads or
4926 the main event loop thread. This can become a scalability bottleneck.
4927 IOThreads allow device emulation and I/O to run on other host CPUs.
4929 The @option{id} parameter is a unique ID that will be used to reference this
4930 IOThread from @option{-device ...,iothread=@var{id}}. Multiple devices can be
4931 assigned to an IOThread. Note that not all devices support an
4932 @option{iothread} parameter.
4934 The @code{query-iothreads} QMP command lists IOThreads and reports their thread
4935 IDs so that the user can configure host CPU pinning/affinity.
4937 IOThreads use an adaptive polling algorithm to reduce event loop latency.
4938 Instead of entering a blocking system call to monitor file descriptors and then
4939 pay the cost of being woken up when an event occurs, the polling algorithm
4940 spins waiting for events for a short time. The algorithm's default parameters
4941 are suitable for many cases but can be adjusted based on knowledge of the
4942 workload and/or host device latency.
4944 The @option{poll-max-ns} parameter is the maximum number of nanoseconds to busy
4945 wait for events. Polling can be disabled by setting this value to 0.
4947 The @option{poll-grow} parameter is the multiplier used to increase the polling
4948 time when the algorithm detects it is missing events due to not polling long
4951 The @option{poll-shrink} parameter is the divisor used to decrease the polling
4952 time when the algorithm detects it is spending too long polling without
4953 encountering events.
4955 The polling parameters can be modified at run-time using the @code{qom-set} command (where @code{iothread1} is the IOThread's @code{id}):
4958 (qemu) qom-set /objects/iothread1 poll-max-ns 100000
4966 HXCOMM This is the last statement. Insert new options before this line!
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