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 " kernel_irqchip=on|off|split controls accelerated irqchip support (default=off)\n"
36 " vmport=on|off|auto controls emulation of vmport (default: auto)\n"
37 " kvm_shadow_mem=size of KVM shadow MMU in bytes\n"
38 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
39 " mem-merge=on|off controls memory merge support (default: on)\n"
40 " igd-passthru=on|off controls IGD GFX passthrough support (default=off)\n"
41 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
42 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
43 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
44 " nvdimm=on|off controls NVDIMM support (default=off)\n"
45 " enforce-config-section=on|off enforce configuration section migration (default=off)\n"
46 " memory-encryption=@var{} memory encryption object to use (default=none)\n",
49 @item
-machine
[type
=]@
var{name
}[,prop
=@
var{value
}[,...]]
51 Select the emulated machine by @
var{name
}. Use @code
{-machine help
} to list
54 For architectures which aim to support live migration compatibility
55 across releases
, each release will introduce a
new versioned machine
56 type
. For example
, the
2.8.0 release introduced machine types
57 ``pc
-i440fx
-2.8'' and ``pc
-q35
-2.8'' for the x86_64
/i686 architectures
.
59 To allow live migration of guests from QEMU version
2.8.0, to QEMU
60 version
2.9.0, the
2.9.0 version must support the ``pc
-i440fx
-2.8''
61 and ``pc
-q35
-2.8'' machines too
. To allow users live migrating VMs
62 to skip multiple intermediate releases when upgrading
, new releases
63 of QEMU will support machine types from many previous versions
.
65 Supported machine properties are
:
67 @item accel
=@
var{accels1
}[:@
var{accels2
}[:...]]
68 This is used to enable an accelerator
. Depending on the target architecture
,
69 kvm
, xen
, hax
, hvf
, whpx or tcg can be available
. By
default, tcg is used
. If there is
70 more than one accelerator specified
, the next one is used
if the previous one
72 @item kernel_irqchip
=on|off
73 Controls
in-kernel irqchip support
for the chosen accelerator when available
.
74 @item gfx_passthru
=on|off
75 Enables IGD GFX passthrough support
for the chosen machine when available
.
76 @item vmport
=on|off|auto
77 Enables emulation of VMWare IO port
, for vmmouse etc
. auto says to select the
78 value based on accel
. For accel
=xen the
default is off otherwise the
default
80 @item kvm_shadow_mem
=size
81 Defines the size of the KVM shadow MMU
.
82 @item dump
-guest
-core
=on|off
83 Include guest memory
in a core dump
. The
default is on
.
84 @item mem
-merge
=on|off
85 Enables or disables memory merge support
. This feature
, when supported by
86 the host
, de
-duplicates identical memory pages among VMs instances
88 @item aes
-key
-wrap
=on|off
89 Enables or disables AES key wrapping support on s390
-ccw hosts
. This feature
90 controls whether AES wrapping keys will be created to allow
91 execution of AES cryptographic functions
. The
default is on
.
92 @item dea
-key
-wrap
=on|off
93 Enables or disables DEA key wrapping support on s390
-ccw hosts
. This feature
94 controls whether DEA wrapping keys will be created to allow
95 execution of DEA cryptographic functions
. The
default is on
.
97 Enables or disables NVDIMM support
. The
default is off
.
98 @item enforce
-config
-section
=on|off
99 If @option
{enforce
-config
-section
} is set to @
var{on
}, force migration
100 code to send configuration section even
if the machine
-type sets the
101 @option
{migration
.send
-configuration
} property to @
var{off
}.
102 NOTE
: this parameter is deprecated
. Please use @option
{-global
}
103 @option
{migration
.send
-configuration
}=@
var{on|off
} instead
.
104 @item memory
-encryption
=@
var{}
105 Memory encryption object to use
. The
default is none
.
109 HXCOMM Deprecated by
-machine
110 DEF("M", HAS_ARG
, QEMU_OPTION_M
, "", QEMU_ARCH_ALL
)
112 DEF("cpu", HAS_ARG
, QEMU_OPTION_cpu
,
113 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL
)
115 @item
-cpu @
var{model
}
117 Select CPU
model (@code
{-cpu help
} for list and additional feature selection
)
120 DEF("accel", HAS_ARG
, QEMU_OPTION_accel
,
121 "-accel [accel=]accelerator[,thread=single|multi]\n"
122 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n"
123 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL
)
125 @item
-accel @
var{name
}[,prop
=@
var{value
}[,...]]
127 This is used to enable an accelerator
. Depending on the target architecture
,
128 kvm
, xen
, hax
, hvf
, whpx or tcg can be available
. By
default, tcg is used
. If there is
129 more than one accelerator specified
, the next one is used
if the previous one
132 @item thread
=single|multi
133 Controls number of TCG threads
. When the TCG is multi
-threaded there will be one
134 thread per vCPU therefor taking advantage of additional host cores
. The
default
135 is to enable multi
-threading where both the back
-end and front
-ends support it and
136 no incompatible TCG features have been
enabled (e
.g
. icount
/replay
).
140 DEF("smp", HAS_ARG
, QEMU_OPTION_smp
,
141 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
142 " set the number of CPUs to 'n' [default=1]\n"
143 " maxcpus= maximum number of total cpus, including\n"
144 " offline CPUs for hotplug, etc\n"
145 " cores= number of CPU cores on one socket (for PC, it's on one die)\n"
146 " threads= number of threads on one CPU core\n"
147 " dies= number of CPU dies on one socket (for PC only)\n"
148 " sockets= number of discrete sockets in the system\n",
151 @item
-smp
[cpus
=]@
var{n
}[,cores
=@
var{cores
}][,threads
=@
var{threads
}][,dies
=dies
][,sockets
=@
var{sockets
}][,maxcpus
=@
var{maxcpus
}]
153 Simulate an SMP system with @
var{n
} CPUs
. On the PC target
, up to
255
154 CPUs are supported
. On Sparc32 target
, Linux limits the number of usable CPUs
156 For the PC target
, the number of @
var{cores
} per die
, the number of @
var{threads
}
157 per cores
, the number of @
var{dies
} per packages and the total number of
158 @
var{sockets
} can be specified
. Missing values will be computed
.
159 If any on the three values is given
, the total number of CPUs @
var{n
} can be omitted
.
160 @
var{maxcpus
} specifies the maximum number of hotpluggable CPUs
.
163 DEF("numa", HAS_ARG
, QEMU_OPTION_numa
,
164 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
165 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
166 "-numa dist,src=source,dst=destination,val=distance\n"
167 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n",
170 @item
-numa node
[,mem
=@
var{size
}][,cpus
=@
var{firstcpu
}[-@
var{lastcpu
}]][,nodeid
=@
var{node
}]
171 @itemx
-numa node
[,memdev
=@
var{id
}][,cpus
=@
var{firstcpu
}[-@
var{lastcpu
}]][,nodeid
=@
var{node
}]
172 @itemx
-numa dist
,src
=@
var{source
},dst
=@
var{destination
},val
=@
var{distance
}
173 @itemx
-numa cpu
,node
-id
=@
var{node
}[,socket
-id
=@
var{x
}][,core
-id
=@
var{y
}][,thread
-id
=@
var{z
}]
175 Define a NUMA node and assign RAM and VCPUs to it
.
176 Set the NUMA distance from a source node to a destination node
.
178 Legacy VCPU assignment uses @samp
{cpus
} option where
179 @
var{firstcpu
} and @
var{lastcpu
} are CPU indexes
. Each
180 @samp
{cpus
} option represent a contiguous range of CPU indexes
181 (or a single VCPU
if @
var{lastcpu
} is omitted
). A non
-contiguous
182 set of VCPUs can be represented by providing multiple @samp
{cpus
}
183 options
. If @samp
{cpus
} is omitted on all nodes
, VCPUs are automatically
186 For example
, the following option assigns VCPUs
0, 1, 2 and
5 to
189 -numa node
,cpus
=0-2,cpus
=5
192 @samp
{cpu
} option is a
new alternative to @samp
{cpus
} option
193 which uses @samp
{socket
-id|core
-id|thread
-id
} properties to assign
194 CPU objects to a @
var{node
} using topology layout properties of CPU
.
195 The set of properties is machine specific
, and depends on used
196 machine type
/@samp
{smp
} options
. It could be queried with
197 @samp
{hotpluggable
-cpus
} monitor command
.
198 @samp
{node
-id
} property specifies @
var{node
} to which CPU object
199 will be assigned
, it
's required for @var{node} to be declared
200 with @samp{node} option before it's used with @samp
{cpu
} option
.
205 -smp
1,sockets
=2,maxcpus
=2 \
206 -numa node
,nodeid
=0 -numa node
,nodeid
=1 \
207 -numa cpu
,node
-id
=0,socket
-id
=0 -numa cpu
,node
-id
=1,socket
-id
=1
210 @samp
{mem
} assigns a given RAM amount to a node
. @samp
{memdev
}
211 assigns RAM from a given memory backend device to a node
. If
212 @samp
{mem
} and @samp
{memdev
} are omitted
in all nodes
, RAM is
213 split equally between them
.
215 @samp
{mem
} and @samp
{memdev
} are mutually exclusive
. Furthermore
,
216 if one node uses @samp
{memdev
}, all of them have to use it
.
218 @
var{source
} and @
var{destination
} are NUMA node IDs
.
219 @
var{distance
} is the NUMA distance from @
var{source
} to @
var{destination
}.
220 The distance from a node to itself is always
10. If any pair of nodes is
221 given a distance
, then all pairs must be given distances
. Although
, when
222 distances are only given
in one direction
for each pair of nodes
, then
223 the distances
in the opposite directions are assumed to be the same
. If
,
224 however
, an asymmetrical pair of distances is given
for even one node
225 pair
, then all node pairs must be provided distance values
for both
226 directions
, even when they are symmetrical
. When a node is unreachable
227 from another node
, set the pair
's distance to 255.
229 Note that the -@option{numa} option doesn't allocate any of the
230 specified resources
, it just assigns existing resources to NUMA
231 nodes
. This means that one still has to use the @option
{-m
},
232 @option
{-smp
} options to allocate RAM and VCPUs respectively
.
236 DEF("add-fd", HAS_ARG
, QEMU_OPTION_add_fd
,
237 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
238 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL
)
240 @item
-add
-fd fd
=@
var{fd
},set
=@
var{set
}[,opaque
=@
var{opaque
}]
243 Add a file descriptor to an fd set
. Valid options are
:
247 This option defines the file descriptor of which a duplicate is added to fd set
.
248 The file descriptor cannot be stdin
, stdout
, or stderr
.
250 This option defines the ID of the fd set to add the file descriptor to
.
251 @item opaque
=@
var{opaque
}
252 This option defines a free
-form string that can be used to describe @
var{fd
}.
255 You can open an image
using pre
-opened file descriptors from an fd set
:
257 @value
{qemu_system
} \
258 -add
-fd fd
=3,set
=2,opaque
="rdwr:/path/to/file" \
259 -add
-fd fd
=4,set
=2,opaque
="rdonly:/path/to/file" \
260 -drive file
=/dev
/fdset
/2,index
=0,media
=disk
264 DEF("set", HAS_ARG
, QEMU_OPTION_set
,
265 "-set group.id.arg=value\n"
266 " set <arg> parameter for item <id> of type <group>\n"
267 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL
)
269 @item
-set @
var{group
}.@
var{id
}.@
var{arg
}=@
var{value
}
271 Set parameter @
var{arg
} for item @
var{id
} of type @
var{group
}
274 DEF("global", HAS_ARG
, QEMU_OPTION_global
,
275 "-global driver.property=value\n"
276 "-global driver=driver,property=property,value=value\n"
277 " set a global default for a driver property\n",
280 @item
-global @
var{driver
}.@
var{prop
}=@
var{value
}
281 @itemx
-global driver
=@
var{driver
},property
=@
var{property
},value
=@
var{value
}
283 Set
default value of @
var{driver
}'s property @var{prop} to @var{value}, e.g.:
286 @value{qemu_system_x86} -global ide-hd.physical_block_size=4096 disk-image.img
289 In particular, you can use this to set driver properties for devices which are
290 created automatically by the machine model. To create a device which is not
291 created automatically and set properties on it, use -@option{device}.
293 -global @var{driver}.@var{prop}=@var{value} is shorthand for -global
294 driver=@var{driver},property=@var{prop},value=@var{value}. The
295 longhand syntax works even when @var{driver} contains a dot.
298 DEF("boot", HAS_ARG, QEMU_OPTION_boot,
299 "-boot [order=drives][,once=drives][,menu=on|off]\n"
300 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
301 " 'drives
': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
302 " 'sp_name
': the file's name that would be passed to bios as logo picture
, if menu
=on
\n"
303 " 'sp_time': the period that splash picture last
if menu
=on
, unit is ms
\n"
304 " 'rb_timeout': the timeout before guest reboot when boot failed
, unit is ms
\n",
307 @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]
309 Specify boot order @var{drives} as a string of drive letters. Valid
310 drive letters depend on the target architecture. The x86 PC uses: a, b
311 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
312 from network adapter 1-4), hard disk boot is the default. To apply a
313 particular boot order only on the first startup, specify it via
314 @option{once}. Note that the @option{order} or @option{once} parameter
315 should not be used together with the @option{bootindex} property of
316 devices, since the firmware implementations normally do not support both
319 Interactive boot menus/prompts can be enabled via @option{menu=on} as far
320 as firmware/BIOS supports them. The default is non-interactive boot.
322 A splash picture could be passed to bios, enabling user to show it as logo,
323 when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
324 supports them. Currently Seabios for X86 system support it.
325 limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
326 format(true color). The resolution should be supported by the SVGA mode, so
327 the recommended is 320x240, 640x480, 800x640.
329 A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
330 when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
331 reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
334 Do strict boot via @option{strict=on} as far as firmware/BIOS
335 supports it. This only effects when boot priority is changed by
336 bootindex options. The default is non-strict boot.
339 # try to boot from network first, then from hard disk
340 @value{qemu_system_x86} -boot order=nc
341 # boot from CD-ROM first, switch back to default order after reboot
342 @value{qemu_system_x86} -boot once=d
343 # boot with a splash picture for 5 seconds.
344 @value{qemu_system_x86} -boot menu=on,splash=/root/boot.bmp,splash-time=5000
347 Note: The legacy format '-boot @var{drives}' is still supported but its
348 use is discouraged as it may be removed from future versions.
351 DEF("m
", HAS_ARG, QEMU_OPTION_m,
352 "-m
[size
=]megs
[,slots
=n
,maxmem
=size
]\n"
353 " configure guest RAM
\n"
354 " size
: initial amount of guest memory
\n"
355 " slots
: number of hotplug
slots (default: none
)\n"
356 " maxmem
: maximum amount of guest
memory (default: none
)\n"
357 "NOTE
: Some architectures might enforce a specific granularity
\n",
360 @item -m [size=]@var{megs}[,slots=n,maxmem=size]
362 Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB.
363 Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in
364 megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem}
365 could be used to set amount of hotpluggable memory slots and maximum amount of
366 memory. Note that @var{maxmem} must be aligned to the page size.
368 For example, the following command-line sets the guest startup RAM size to
369 1GB, creates 3 slots to hotplug additional memory and sets the maximum
370 memory the guest can reach to 4GB:
373 @value{qemu_system} -m 1G,slots=3,maxmem=4G
376 If @var{slots} and @var{maxmem} are not specified, memory hotplug won't
377 be enabled and the guest startup RAM will never increase.
380 DEF("mem
-path
", HAS_ARG, QEMU_OPTION_mempath,
381 "-mem
-path FILE provide backing storage
for guest RAM
\n", QEMU_ARCH_ALL)
383 @item -mem-path @var{path}
385 Allocate guest RAM from a temporarily created file in @var{path}.
388 DEF("mem
-prealloc
", 0, QEMU_OPTION_mem_prealloc,
389 "-mem
-prealloc preallocate guest
memory (use with
-mem
-path
)\n",
393 @findex -mem-prealloc
394 Preallocate memory when using -mem-path.
397 DEF("k
", HAS_ARG, QEMU_OPTION_k,
398 "-k language use keyboard
layout (for example
'fr' for French
)\n",
401 @item -k @var{language}
403 Use keyboard layout @var{language} (for example @code{fr} for
404 French). This option is only needed where it is not easy to get raw PC
405 keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
406 display). You don't normally need to use it on PC/Linux or PC/Windows
409 The available layouts are:
411 ar de-ch es fo fr-ca hu ja mk no pt-br sv
412 da en-gb et fr fr-ch is lt nl pl ru th
413 de en-us fi fr-be hr it lv nl-be pt sl tr
416 The default is @code{en-us}.
420 HXCOMM Deprecated by -audiodev
421 DEF("audio
-help
", 0, QEMU_OPTION_audio_help,
422 "-audio
-help show
-audiodev equivalent of the currently specified audio settings
\n",
427 Will show the -audiodev equivalent of the currently specified
428 (deprecated) environment variables.
431 DEF("audiodev
", HAS_ARG, QEMU_OPTION_audiodev,
432 "-audiodev
[driver
=]driver
,id
=id
[,prop
[=value
][,...]]\n"
433 " specifies the audio backend to use
\n"
434 " id
= identifier of the backend
\n"
435 " timer
-period
= timer period
in microseconds
\n"
436 " in|out
.fixed
-settings
= use fixed settings
for host audio
\n"
437 " in|out
.frequency
= frequency to use with fixed settings
\n"
438 " in|out
.channels
= number of channels to use with fixed settings
\n"
439 " in|out
.format
= sample format to use with fixed settings
\n"
440 " valid values
: s8
, s16
, s32
, u8
, u16
, u32
\n"
441 " in|out
.voices
= number of voices to use
\n"
442 " in|out
.buffer
-len
= length of buffer
in microseconds
\n"
443 "-audiodev none
,id
=id
,[,prop
[=value
][,...]]\n"
444 " dummy driver that discards all output
\n"
445 #ifdef CONFIG_AUDIO_ALSA
446 "-audiodev alsa
,id
=id
[,prop
[=value
][,...]]\n"
447 " in|out
.dev
= name of the audio device to use
\n"
448 " in|out
.period
-len
= length of period
in microseconds
\n"
449 " in|out
.try-poll
= attempt to use poll mode
\n"
450 " threshold
= threshold (in microseconds
) when playback starts
\n"
452 #ifdef CONFIG_AUDIO_COREAUDIO
453 "-audiodev coreaudio
,id
=id
[,prop
[=value
][,...]]\n"
454 " in|out
.buffer
-count
= number of buffers
\n"
456 #ifdef CONFIG_AUDIO_DSOUND
457 "-audiodev dsound
,id
=id
[,prop
[=value
][,...]]\n"
458 " latency
= add extra latency to playback
in microseconds
\n"
460 #ifdef CONFIG_AUDIO_OSS
461 "-audiodev oss
,id
=id
[,prop
[=value
][,...]]\n"
462 " in|out
.dev
= path of the audio device to use
\n"
463 " in|out
.buffer
-count
= number of buffers
\n"
464 " in|out
.try-poll
= attempt to use poll mode
\n"
465 " try-mmap
= try using memory mapped access
\n"
466 " exclusive
= open device
in exclusive mode
\n"
467 " dsp
-policy
= set timing
policy (0..10), -1 to use fragment mode
\n"
469 #ifdef CONFIG_AUDIO_PA
470 "-audiodev pa
,id
=id
[,prop
[=value
][,...]]\n"
471 " server
= PulseAudio server address
\n"
472 " in|out
.name
= source
/sink device name
\n"
474 #ifdef CONFIG_AUDIO_SDL
475 "-audiodev sdl
,id
=id
[,prop
[=value
][,...]]\n"
478 "-audiodev spice
,id
=id
[,prop
[=value
][,...]]\n"
480 "-audiodev wav
,id
=id
[,prop
[=value
][,...]]\n"
481 " path
= path of wav file to record
\n",
484 @item -audiodev [driver=]@var{driver},id=@var{id}[,@var{prop}[=@var{value}][,...]]
486 Adds a new audio backend @var{driver} identified by @var{id}. There are
487 global and driver specific properties. Some values can be set
488 differently for input and output, they're marked with @code{in|out.}.
489 You can set the input's property with @code{in.@var{prop}} and the
490 output's property with @code{out.@var{prop}}. For example:
492 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
493 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
496 Valid global options are:
499 @item id=@var{identifier}
500 Identifies the audio backend.
502 @item timer-period=@var{period}
503 Sets the timer @var{period} used by the audio subsystem in microseconds.
504 Default is 10000 (10 ms).
506 @item in|out.fixed-settings=on|off
507 Use fixed settings for host audio. When off, it will change based on
508 how the guest opens the sound card. In this case you must not specify
509 @var{frequency}, @var{channels} or @var{format}. Default is on.
511 @item in|out.frequency=@var{frequency}
512 Specify the @var{frequency} to use when using @var{fixed-settings}.
515 @item in|out.channels=@var{channels}
516 Specify the number of @var{channels} to use when using
517 @var{fixed-settings}. Default is 2 (stereo).
519 @item in|out.format=@var{format}
520 Specify the sample @var{format} to use when using @var{fixed-settings}.
521 Valid values are: @code{s8}, @code{s16}, @code{s32}, @code{u8},
522 @code{u16}, @code{u32}. Default is @code{s16}.
524 @item in|out.voices=@var{voices}
525 Specify the number of @var{voices} to use. Default is 1.
527 @item in|out.buffer=@var{usecs}
528 Sets the size of the buffer in microseconds.
532 @item -audiodev none,id=@var{id}[,@var{prop}[=@var{value}][,...]]
533 Creates a dummy backend that discards all outputs. This backend has no
534 backend specific properties.
536 @item -audiodev alsa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
537 Creates backend using the ALSA. This backend is only available on
540 ALSA specific options are:
544 @item in|out.dev=@var{device}
545 Specify the ALSA @var{device} to use for input and/or output. Default
548 @item in|out.period-len=@var{usecs}
549 Sets the period length in microseconds.
551 @item in|out.try-poll=on|off
552 Attempt to use poll mode with the device. Default is on.
554 @item threshold=@var{threshold}
555 Threshold (in microseconds) when playback starts. Default is 0.
559 @item -audiodev coreaudio,id=@var{id}[,@var{prop}[=@var{value}][,...]]
560 Creates a backend using Apple's Core Audio. This backend is only
561 available on Mac OS and only supports playback.
563 Core Audio specific options are:
567 @item in|out.buffer-count=@var{count}
568 Sets the @var{count} of the buffers.
572 @item -audiodev dsound,id=@var{id}[,@var{prop}[=@var{value}][,...]]
573 Creates a backend using Microsoft's DirectSound. This backend is only
574 available on Windows and only supports playback.
576 DirectSound specific options are:
580 @item latency=@var{usecs}
581 Add extra @var{usecs} microseconds latency to playback. Default is
586 @item -audiodev oss,id=@var{id}[,@var{prop}[=@var{value}][,...]]
587 Creates a backend using OSS. This backend is available on most
590 OSS specific options are:
594 @item in|out.dev=@var{device}
595 Specify the file name of the OSS @var{device} to use. Default is
598 @item in|out.buffer-count=@var{count}
599 Sets the @var{count} of the buffers.
601 @item in|out.try-poll=on|of
602 Attempt to use poll mode with the device. Default is on.
604 @item try-mmap=on|off
605 Try using memory mapped device access. Default is off.
607 @item exclusive=on|off
608 Open the device in exclusive mode (vmix won't work in this case).
611 @item dsp-policy=@var{policy}
612 Sets the timing policy (between 0 and 10, where smaller number means
613 smaller latency but higher CPU usage). Use -1 to use buffer sizes
614 specified by @code{buffer} and @code{buffer-count}. This option is
615 ignored if you do not have OSS 4. Default is 5.
619 @item -audiodev pa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
620 Creates a backend using PulseAudio. This backend is available on most
623 PulseAudio specific options are:
627 @item server=@var{server}
628 Sets the PulseAudio @var{server} to connect to.
630 @item in|out.name=@var{sink}
631 Use the specified source/sink for recording/playback.
635 @item -audiodev sdl,id=@var{id}[,@var{prop}[=@var{value}][,...]]
636 Creates a backend using SDL. This backend is available on most systems,
637 but you should use your platform's native backend if possible. This
638 backend has no backend specific properties.
640 @item -audiodev spice,id=@var{id}[,@var{prop}[=@var{value}][,...]]
641 Creates a backend that sends audio through SPICE. This backend requires
642 @code{-spice} and automatically selected in that case, so usually you
643 can ignore this option. This backend has no backend specific
646 @item -audiodev wav,id=@var{id}[,@var{prop}[=@var{value}][,...]]
647 Creates a backend that writes audio to a WAV file.
649 Backend specific options are:
653 @item path=@var{path}
654 Write recorded audio into the specified file. Default is
660 DEF("soundhw
", HAS_ARG, QEMU_OPTION_soundhw,
661 "-soundhw c1
,... enable audio support
\n"
662 " and only specified sound
cards (comma separated list
)\n"
663 " use
'-soundhw help' to get the list of supported cards
\n"
664 " use
'-soundhw all' to enable all of them
\n", QEMU_ARCH_ALL)
666 @item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
668 Enable audio and selected sound hardware. Use 'help' to print all
669 available sound hardware. For example:
672 @value{qemu_system_x86} -soundhw sb16,adlib disk.img
673 @value{qemu_system_x86} -soundhw es1370 disk.img
674 @value{qemu_system_x86} -soundhw ac97 disk.img
675 @value{qemu_system_x86} -soundhw hda disk.img
676 @value{qemu_system_x86} -soundhw all disk.img
677 @value{qemu_system_x86} -soundhw help
680 Note that Linux's i810_audio OSS kernel (for AC97) module might
681 require manually specifying clocking.
684 modprobe i810_audio clocking=48000
688 DEF("device
", HAS_ARG, QEMU_OPTION_device,
689 "-device driver
[,prop
[=value
][,...]]\n"
690 " add
device (based on driver
)\n"
691 " prop
=value
,... sets driver properties
\n"
692 " use
'-device help' to print all possible drivers
\n"
693 " use
'-device driver,help' to print all possible properties
\n",
696 @item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
698 Add device @var{driver}. @var{prop}=@var{value} sets driver
699 properties. Valid properties depend on the driver. To get help on
700 possible drivers and properties, use @code{-device help} and
701 @code{-device @var{driver},help}.
704 @item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}][,guid=@var{uuid}]
706 Add an IPMI BMC. This is a simulation of a hardware management
707 interface processor that normally sits on a system. It provides
708 a watchdog and the ability to reset and power control the system.
709 You need to connect this to an IPMI interface to make it useful
711 The IPMI slave address to use for the BMC. The default is 0x20.
712 This address is the BMC's address on the I2C network of management
713 controllers. If you don't know what this means, it is safe to ignore
718 The BMC id for interfaces to use this device.
719 @item slave_addr=@var{val}
720 Define slave address to use for the BMC. The default is 0x20.
721 @item sdrfile=@var{file}
722 file containing raw Sensor Data Records (SDR) data. The default is none.
723 @item fruareasize=@var{val}
724 size of a Field Replaceable Unit (FRU) area. The default is 1024.
725 @item frudatafile=@var{file}
726 file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
727 @item guid=@var{uuid}
728 value for the GUID for the BMC, in standard UUID format. If this is set,
729 get "Get GUID
" command to the BMC will return it. Otherwise "Get GUID
"
730 will return an error.
733 @item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
735 Add a connection to an external IPMI BMC simulator. Instead of
736 locally emulating the BMC like the above item, instead connect
737 to an external entity that provides the IPMI services.
739 A connection is made to an external BMC simulator. If you do this, it
740 is strongly recommended that you use the "reconnect
=" chardev option
741 to reconnect to the simulator if the connection is lost. Note that if
742 this is not used carefully, it can be a security issue, as the
743 interface has the ability to send resets, NMIs, and power off the VM.
744 It's best if QEMU makes a connection to an external simulator running
745 on a secure port on localhost, so neither the simulator nor QEMU is
746 exposed to any outside network.
748 See the "lanserv
/README
.vm
" file in the OpenIPMI library for more
749 details on the external interface.
751 @item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
753 Add a KCS IPMI interafce on the ISA bus. This also adds a
754 corresponding ACPI and SMBIOS entries, if appropriate.
758 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
759 @item ioport=@var{val}
760 Define the I/O address of the interface. The default is 0xca0 for KCS.
762 Define the interrupt to use. The default is 5. To disable interrupts,
766 @item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
768 Like the KCS interface, but defines a BT interface. The default port is
769 0xe4 and the default interrupt is 5.
773 DEF("name
", HAS_ARG, QEMU_OPTION_name,
774 "-name string1
[,process
=string2
][,debug
-threads
=on|off
]\n"
775 " set the name of the guest
\n"
776 " string1 sets the window title and string2 the process name
\n"
777 " When debug
-threads is enabled
, individual threads are given a separate name
\n"
778 " NOTE
: The thread names are
for debugging and not a stable API
.\n",
781 @item -name @var{name}
783 Sets the @var{name} of the guest.
784 This name will be displayed in the SDL window caption.
785 The @var{name} will also be used for the VNC server.
786 Also optionally set the top visible process name in Linux.
787 Naming of individual threads can also be enabled on Linux to aid debugging.
790 DEF("uuid
", HAS_ARG, QEMU_OPTION_uuid,
791 "-uuid
%08x
-%04x
-%04x
-%04x
-%012x
\n"
792 " specify machine UUID
\n", QEMU_ARCH_ALL)
794 @item -uuid @var{uuid}
804 DEFHEADING(Block device options:)
809 DEF("fda
", HAS_ARG, QEMU_OPTION_fda,
810 "-fda
/-fdb file use
'file' as floppy disk
0/1 image
\n", QEMU_ARCH_ALL)
811 DEF("fdb
", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
813 @item -fda @var{file}
814 @itemx -fdb @var{file}
817 Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
820 DEF("hda
", HAS_ARG, QEMU_OPTION_hda,
821 "-hda
/-hdb file use
'file' as IDE hard disk
0/1 image
\n", QEMU_ARCH_ALL)
822 DEF("hdb
", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
823 DEF("hdc
", HAS_ARG, QEMU_OPTION_hdc,
824 "-hdc
/-hdd file use
'file' as IDE hard disk
2/3 image
\n", QEMU_ARCH_ALL)
825 DEF("hdd
", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
827 @item -hda @var{file}
828 @itemx -hdb @var{file}
829 @itemx -hdc @var{file}
830 @itemx -hdd @var{file}
835 Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
838 DEF("cdrom
", HAS_ARG, QEMU_OPTION_cdrom,
839 "-cdrom file use
'file' as IDE cdrom
image (cdrom is ide1 master
)\n",
842 @item -cdrom @var{file}
844 Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
845 @option{-cdrom} at the same time). You can use the host CD-ROM by
846 using @file{/dev/cdrom} as filename (@pxref{host_drives}).
849 DEF("blockdev
", HAS_ARG, QEMU_OPTION_blockdev,
850 "-blockdev
[driver
=]driver
[,node
-name
=N
][,discard
=ignore|unmap
]\n"
851 " [,cache
.direct
=on|off
][,cache
.no
-flush
=on|off
]\n"
852 " [,read
-only
=on|off
][,detect
-zeroes
=on|off|unmap
]\n"
853 " [,driver specific parameters
...]\n"
854 " configure a block backend
\n", QEMU_ARCH_ALL)
856 @item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
859 Define a new block driver node. Some of the options apply to all block drivers,
860 other options are only accepted for a specific block driver. See below for a
861 list of generic options and options for the most common block drivers.
863 Options that expect a reference to another node (e.g. @code{file}) can be
864 given in two ways. Either you specify the node name of an already existing node
865 (file=@var{node-name}), or you define a new node inline, adding options
866 for the referenced node after a dot (file.filename=@var{path},file.aio=native).
868 A block driver node created with @option{-blockdev} can be used for a guest
869 device by specifying its node name for the @code{drive} property in a
870 @option{-device} argument that defines a block device.
873 @item Valid options for any block driver node:
877 Specifies the block driver to use for the given node.
879 This defines the name of the block driver node by which it will be referenced
880 later. The name must be unique, i.e. it must not match the name of a different
881 block driver node, or (if you use @option{-drive} as well) the ID of a drive.
883 If no node name is specified, it is automatically generated. The generated node
884 name is not intended to be predictable and changes between QEMU invocations.
885 For the top level, an explicit node name must be specified.
887 Open the node read-only. Guest write attempts will fail.
889 The host page cache can be avoided with @option{cache.direct=on}. This will
890 attempt to do disk IO directly to the guest's memory. QEMU may still perform an
891 internal copy of the data.
893 In case you don't care about data integrity over host failures, you can use
894 @option{cache.no-flush=on}. This option tells QEMU that it never needs to write
895 any data to the disk but can instead keep things in cache. If anything goes
896 wrong, like your host losing power, the disk storage getting disconnected
897 accidentally, etc. your image will most probably be rendered unusable.
898 @item discard=@var{discard}
899 @var{discard} is one of "ignore
" (or "off
") or "unmap
" (or "on
") and controls
900 whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are
901 ignored or passed to the filesystem. Some machine types may not support
903 @item detect-zeroes=@var{detect-zeroes}
904 @var{detect-zeroes} is "off
", "on
" or "unmap
" and enables the automatic
905 conversion of plain zero writes by the OS to driver specific optimized
906 zero write commands. You may even choose "unmap
" if @var{discard} is set
907 to "unmap
" to allow a zero write to be converted to an @code{unmap} operation.
910 @item Driver-specific options for @code{file}
912 This is the protocol-level block driver for accessing regular files.
916 The path to the image file in the local filesystem
918 Specifies the AIO backend (threads/native, default: threads)
920 Specifies whether the image file is protected with Linux OFD / POSIX locks. The
921 default is to use the Linux Open File Descriptor API if available, otherwise no
922 lock is applied. (auto/on/off, default: auto)
926 -blockdev driver=file,node-name=disk,filename=disk.img
929 @item Driver-specific options for @code{raw}
931 This is the image format block driver for raw images. It is usually
932 stacked on top of a protocol level block driver such as @code{file}.
936 Reference to or definition of the data source block driver node
937 (e.g. a @code{file} driver node)
941 -blockdev driver=file,node-name=disk_file,filename=disk.img
942 -blockdev driver=raw,node-name=disk,file=disk_file
946 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
949 @item Driver-specific options for @code{qcow2}
951 This is the image format block driver for qcow2 images. It is usually
952 stacked on top of a protocol level block driver such as @code{file}.
956 Reference to or definition of the data source block driver node
957 (e.g. a @code{file} driver node)
960 Reference to or definition of the backing file block device (default is taken
961 from the image file). It is allowed to pass @code{null} here in order to disable
962 the default backing file.
965 Whether to enable the lazy refcounts feature (on/off; default is taken from the
969 The maximum total size of the L2 table and refcount block caches in bytes
970 (default: the sum of l2-cache-size and refcount-cache-size)
973 The maximum size of the L2 table cache in bytes
974 (default: if cache-size is not specified - 32M on Linux platforms, and 8M on
975 non-Linux platforms; otherwise, as large as possible within the cache-size,
976 while permitting the requested or the minimal refcount cache size)
978 @item refcount-cache-size
979 The maximum size of the refcount block cache in bytes
980 (default: 4 times the cluster size; or if cache-size is specified, the part of
981 it which is not used for the L2 cache)
983 @item cache-clean-interval
984 Clean unused entries in the L2 and refcount caches. The interval is in seconds.
985 The default value is 600 on supporting platforms, and 0 on other platforms.
986 Setting it to 0 disables this feature.
988 @item pass-discard-request
989 Whether discard requests to the qcow2 device should be forwarded to the data
990 source (on/off; default: on if discard=unmap is specified, off otherwise)
992 @item pass-discard-snapshot
993 Whether discard requests for the data source should be issued when a snapshot
994 operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off;
997 @item pass-discard-other
998 Whether discard requests for the data source should be issued on other
999 occasions where a cluster gets freed (on/off; default: off)
1002 Which overlap checks to perform for writes to the image
1003 (none/constant/cached/all; default: cached). For details or finer
1004 granularity control refer to the QAPI documentation of @code{blockdev-add}.
1009 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1010 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1014 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1017 @item Driver-specific options for other drivers
1018 Please refer to the QAPI documentation of the @code{blockdev-add} QMP command.
1024 DEF("drive
", HAS_ARG, QEMU_OPTION_drive,
1025 "-drive
[file
=file
][,if=type
][,bus
=n
][,unit
=m
][,media
=d
][,index
=i
]\n"
1026 " [,cache
=writethrough|writeback|none|directsync|unsafe
][,format
=f
]\n"
1027 " [,snapshot
=on|off
][,rerror
=ignore|stop|report
]\n"
1028 " [,werror
=ignore|stop|report|enospc
][,id
=name
][,aio
=threads|native
]\n"
1029 " [,readonly
=on|off
][,copy
-on
-read
=on|off
]\n"
1030 " [,discard
=ignore|unmap
][,detect
-zeroes
=on|off|unmap
]\n"
1031 " [[,bps
=b
]|
[[,bps_rd
=r
][,bps_wr
=w
]]]\n"
1032 " [[,iops
=i
]|
[[,iops_rd
=r
][,iops_wr
=w
]]]\n"
1033 " [[,bps_max
=bm
]|
[[,bps_rd_max
=rm
][,bps_wr_max
=wm
]]]\n"
1034 " [[,iops_max
=im
]|
[[,iops_rd_max
=irm
][,iops_wr_max
=iwm
]]]\n"
1035 " [[,iops_size
=is
]]\n"
1037 " use
'file' as a drive image
\n", QEMU_ARCH_ALL)
1039 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
1042 Define a new drive. This includes creating a block driver node (the backend) as
1043 well as a guest device, and is mostly a shortcut for defining the corresponding
1044 @option{-blockdev} and @option{-device} options.
1046 @option{-drive} accepts all options that are accepted by @option{-blockdev}. In
1047 addition, it knows the following options:
1050 @item file=@var{file}
1051 This option defines which disk image (@pxref{disk_images}) to use with
1052 this drive. If the filename contains comma, you must double it
1053 (for instance, "file
=my
,,file
" to use file "my
,file
").
1055 Special files such as iSCSI devices can be specified using protocol
1056 specific URLs. See the section for "Device URL Syntax
" for more information.
1057 @item if=@var{interface}
1058 This option defines on which type on interface the drive is connected.
1059 Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none.
1060 @item bus=@var{bus},unit=@var{unit}
1061 These options define where is connected the drive by defining the bus number and
1063 @item index=@var{index}
1064 This option defines where is connected the drive by using an index in the list
1065 of available connectors of a given interface type.
1066 @item media=@var{media}
1067 This option defines the type of the media: disk or cdrom.
1068 @item snapshot=@var{snapshot}
1069 @var{snapshot} is "on
" or "off
" and controls snapshot mode for the given drive
1070 (see @option{-snapshot}).
1071 @item cache=@var{cache}
1072 @var{cache} is "none
", "writeback
", "unsafe
", "directsync
" or "writethrough
"
1073 and controls how the host cache is used to access block data. This is a
1074 shortcut that sets the @option{cache.direct} and @option{cache.no-flush}
1075 options (as in @option{-blockdev}), and additionally @option{cache.writeback},
1076 which provides a default for the @option{write-cache} option of block guest
1077 devices (as in @option{-device}). The modes correspond to the following
1080 @c Our texi2pod.pl script doesn't support @multitable, so fall back to using
1081 @c plain ASCII art (well, UTF-8 art really). This looks okay both in the manpage
1082 @c and the HTML output.
1084 @ │ cache.writeback cache.direct cache.no-flush
1085 ─────────────┼─────────────────────────────────────────────────
1086 writeback │ on off off
1088 writethrough │ off off off
1089 directsync │ off on off
1090 unsafe │ on off on
1093 The default mode is @option{cache=writeback}.
1096 @var{aio} is "threads
", or "native
" and selects between pthread based disk I/O and native Linux AIO.
1097 @item format=@var{format}
1098 Specify which disk @var{format} will be used rather than detecting
1099 the format. Can be used to specify format=raw to avoid interpreting
1100 an untrusted format header.
1101 @item werror=@var{action},rerror=@var{action}
1102 Specify which @var{action} to take on write and read errors. Valid actions are:
1103 "ignore
" (ignore the error and try to continue), "stop
" (pause QEMU),
1104 "report
" (report the error to the guest), "enospc
" (pause QEMU only if the
1105 host disk is full; report the error to the guest otherwise).
1106 The default setting is @option{werror=enospc} and @option{rerror=report}.
1107 @item copy-on-read=@var{copy-on-read}
1108 @var{copy-on-read} is "on
" or "off
" and enables whether to copy read backing
1109 file sectors into the image file.
1110 @item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
1111 Specify bandwidth throttling limits in bytes per second, either for all request
1112 types or for reads or writes only. Small values can lead to timeouts or hangs
1113 inside the guest. A safe minimum for disks is 2 MB/s.
1114 @item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm}
1115 Specify bursts in bytes per second, either for all request types or for reads
1116 or writes only. Bursts allow the guest I/O to spike above the limit
1118 @item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
1119 Specify request rate limits in requests per second, either for all request
1120 types or for reads or writes only.
1121 @item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
1122 Specify bursts in requests per second, either for all request types or for reads
1123 or writes only. Bursts allow the guest I/O to spike above the limit
1125 @item iops_size=@var{is}
1126 Let every @var{is} bytes of a request count as a new request for iops
1127 throttling purposes. Use this option to prevent guests from circumventing iops
1128 limits by sending fewer but larger requests.
1130 Join a throttling quota group with given name @var{g}. All drives that are
1131 members of the same group are accounted for together. Use this option to
1132 prevent guests from circumventing throttling limits by using many small disks
1133 instead of a single larger disk.
1136 By default, the @option{cache.writeback=on} mode is used. It will report data
1137 writes as completed as soon as the data is present in the host page cache.
1138 This is safe as long as your guest OS makes sure to correctly flush disk caches
1139 where needed. If your guest OS does not handle volatile disk write caches
1140 correctly and your host crashes or loses power, then the guest may experience
1143 For such guests, you should consider using @option{cache.writeback=off}. This
1144 means that the host page cache will be used to read and write data, but write
1145 notification will be sent to the guest only after QEMU has made sure to flush
1146 each write to the disk. Be aware that this has a major impact on performance.
1148 When using the @option{-snapshot} option, unsafe caching is always used.
1150 Copy-on-read avoids accessing the same backing file sectors repeatedly and is
1151 useful when the backing file is over a slow network. By default copy-on-read
1154 Instead of @option{-cdrom} you can use:
1156 @value{qemu_system} -drive file=file,index=2,media=cdrom
1159 Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
1162 @value{qemu_system} -drive file=file,index=0,media=disk
1163 @value{qemu_system} -drive file=file,index=1,media=disk
1164 @value{qemu_system} -drive file=file,index=2,media=disk
1165 @value{qemu_system} -drive file=file,index=3,media=disk
1168 You can open an image using pre-opened file descriptors from an fd set:
1170 @value{qemu_system} \
1171 -add-fd fd=3,set=2,opaque="rdwr
:/path
/to
/file
" \
1172 -add-fd fd=4,set=2,opaque="rdonly
:/path
/to
/file
" \
1173 -drive file=/dev/fdset/2,index=0,media=disk
1176 You can connect a CDROM to the slave of ide0:
1178 @value{qemu_system_x86} -drive file=file,if=ide,index=1,media=cdrom
1181 If you don't specify the "file
=" argument, you define an empty drive:
1183 @value{qemu_system_x86} -drive if=ide,index=1,media=cdrom
1186 Instead of @option{-fda}, @option{-fdb}, you can use:
1188 @value{qemu_system_x86} -drive file=file,index=0,if=floppy
1189 @value{qemu_system_x86} -drive file=file,index=1,if=floppy
1192 By default, @var{interface} is "ide
" and @var{index} is automatically
1195 @value{qemu_system_x86} -drive file=a -drive file=b"
1197 is interpreted like
:
1199 @value
{qemu_system_x86
} -hda a
-hdb b
1203 DEF("mtdblock", HAS_ARG
, QEMU_OPTION_mtdblock
,
1204 "-mtdblock file use 'file' as on-board Flash memory image\n",
1207 @item
-mtdblock @
var{file
}
1209 Use @
var{file
} as on
-board Flash memory image
.
1212 DEF("sd", HAS_ARG
, QEMU_OPTION_sd
,
1213 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL
)
1215 @item
-sd @
var{file
}
1217 Use @
var{file
} as SecureDigital card image
.
1220 DEF("pflash", HAS_ARG
, QEMU_OPTION_pflash
,
1221 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL
)
1223 @item
-pflash @
var{file
}
1225 Use @
var{file
} as a parallel flash image
.
1228 DEF("snapshot", 0, QEMU_OPTION_snapshot
,
1229 "-snapshot write to temporary files instead of disk image files\n",
1234 Write to temporary files instead of disk image files
. In
this case,
1235 the raw disk image you use is not written back
. You can however force
1236 the write back by pressing @key
{C
-a s
} (@pxref
{disk_images
}).
1239 DEF("fsdev", HAS_ARG
, QEMU_OPTION_fsdev
,
1240 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1241 " [,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n"
1242 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1243 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1244 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1245 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1246 " [[,throttling.iops-size=is]]\n"
1247 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly]\n"
1248 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly]\n"
1249 "-fsdev synth,id=id\n",
1254 @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
}[,...]]]
1255 @itemx
-fsdev proxy
,id
=@
var{id
},socket
=@
var{socket
}[,writeout
=@
var{writeout
}][,readonly
]
1256 @itemx
-fsdev proxy
,id
=@
var{id
},sock_fd
=@
var{sock_fd
}[,writeout
=@
var{writeout
}][,readonly
]
1257 @itemx
-fsdev synth
,id
=@
var{id
}[,readonly
]
1259 Define a
new file system device
. Valid options are
:
1262 Accesses to the filesystem are done by QEMU
.
1264 Accesses to the filesystem are done by virtfs
-proxy
-helper(1).
1266 Synthetic filesystem
, only used by QTests
.
1268 Specifies identifier
for this device
.
1269 @item path
=@
var{path
}
1270 Specifies the export path
for the file system device
. Files under
1271 this path will be available to the
9p client on the guest
.
1272 @item security_model
=@
var{security_model
}
1273 Specifies the security model to be used
for this export path
.
1274 Supported security models are
"passthrough", "mapped-xattr", "mapped-file" and
"none".
1275 In
"passthrough" security model
, files are stored
using the same
1276 credentials as they are created on the guest
. This requires QEMU
1277 to run as root
. In
"mapped-xattr" security model
, some of the file
1278 attributes like uid
, gid
, mode bits and link target are stored as
1279 file attributes
. For
"mapped-file" these attributes are stored
in the
1280 hidden
.virtfs_metadata directory
. Directories exported by
this security model cannot
1281 interact with other unix tools
. "none" security model is same as
1282 passthrough except the sever won
't report failures if it fails to
1283 set file attributes like ownership. Security model is mandatory
1284 only for local fsdriver. Other fsdrivers (like proxy) don't take
1285 security model as a parameter
.
1286 @item writeout
=@
var{writeout
}
1287 This is an optional argument
. The only supported value is
"immediate".
1288 This means that host page cache will be used to read and write data but
1289 write notification will be sent to the guest only when the data has been
1290 reported as written by the storage subsystem
.
1292 Enables exporting
9p share as a readonly mount
for guests
. By
default
1293 read
-write access is given
.
1294 @item socket
=@
var{socket
}
1295 Enables proxy filesystem driver to use passed socket file
for communicating
1296 with virtfs
-proxy
-helper(1).
1297 @item sock_fd
=@
var{sock_fd
}
1298 Enables proxy filesystem driver to use passed socket descriptor
for
1299 communicating with virtfs
-proxy
-helper(1). Usually a helper like libvirt
1300 will create socketpair and pass one of the fds as sock_fd
.
1301 @item fmode
=@
var{fmode
}
1302 Specifies the
default mode
for newly created files on the host
. Works only
1303 with security models
"mapped-xattr" and
"mapped-file".
1304 @item dmode
=@
var{dmode
}
1305 Specifies the
default mode
for newly created directories on the host
. Works
1306 only with security models
"mapped-xattr" and
"mapped-file".
1307 @item throttling
.bps
-total
=@
var{b
},throttling
.bps
-read
=@
var{r
},throttling
.bps
-write
=@
var{w
}
1308 Specify bandwidth throttling limits
in bytes per second
, either
for all request
1309 types or
for reads or writes only
.
1310 @item throttling
.bps
-total
-max
=@
var{bm
},bps
-read
-max
=@
var{rm
},bps
-write
-max
=@
var{wm
}
1311 Specify bursts
in bytes per second
, either
for all request types or
for reads
1312 or writes only
. Bursts allow the guest I
/O to spike above the limit
1314 @item throttling
.iops
-total
=@
var{i
},throttling
.iops
-read
=@
var{r
}, throttling
.iops
-write
=@
var{w
}
1315 Specify request rate limits
in requests per second
, either
for all request
1316 types or
for reads or writes only
.
1317 @item throttling
.iops
-total
-max
=@
var{im
},throttling
.iops
-read
-max
=@
var{irm
}, throttling
.iops
-write
-max
=@
var{iwm
}
1318 Specify bursts
in requests per second
, either
for all request types or
for reads
1319 or writes only
. Bursts allow the guest I
/O to spike above the limit temporarily
.
1320 @item throttling
.iops
-size
=@
var{is
}
1321 Let every @
var{is
} bytes of a request count as a
new request
for iops
1322 throttling purposes
.
1325 -fsdev option is used along with
-device driver
"virtio-9p-...".
1326 @item
-device virtio
-9p
-@
var{type
},fsdev
=@
var{id
},mount_tag
=@
var{mount_tag
}
1327 Options
for virtio
-9p
-... driver are
:
1330 Specifies the variant to be used
. Supported values are
"pci", "ccw" or
"device",
1331 depending on the machine type
.
1332 @item fsdev
=@
var{id
}
1333 Specifies the id value specified along with
-fsdev option
.
1334 @item mount_tag
=@
var{mount_tag
}
1335 Specifies the tag name to be used by the guest to mount
this export point
.
1340 DEF("virtfs", HAS_ARG
, QEMU_OPTION_virtfs
,
1341 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1342 " [,id=id][,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n"
1343 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly]\n"
1344 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly]\n"
1345 "-virtfs synth,mount_tag=tag[,id=id][,readonly]\n",
1350 @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
}]
1351 @itemx
-virtfs proxy
,socket
=@
var{socket
},mount_tag
=@
var{mount_tag
} [,writeout
=@
var{writeout
}][,readonly
]
1352 @itemx
-virtfs proxy
,sock_fd
=@
var{sock_fd
},mount_tag
=@
var{mount_tag
} [,writeout
=@
var{writeout
}][,readonly
]
1353 @itemx
-virtfs synth
,mount_tag
=@
var{mount_tag
}
1356 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
:
1359 Accesses to the filesystem are done by QEMU
.
1361 Accesses to the filesystem are done by virtfs
-proxy
-helper(1).
1363 Synthetic filesystem
, only used by QTests
.
1365 Specifies identifier
for the filesystem device
1366 @item path
=@
var{path
}
1367 Specifies the export path
for the file system device
. Files under
1368 this path will be available to the
9p client on the guest
.
1369 @item security_model
=@
var{security_model
}
1370 Specifies the security model to be used
for this export path
.
1371 Supported security models are
"passthrough", "mapped-xattr", "mapped-file" and
"none".
1372 In
"passthrough" security model
, files are stored
using the same
1373 credentials as they are created on the guest
. This requires QEMU
1374 to run as root
. In
"mapped-xattr" security model
, some of the file
1375 attributes like uid
, gid
, mode bits and link target are stored as
1376 file attributes
. For
"mapped-file" these attributes are stored
in the
1377 hidden
.virtfs_metadata directory
. Directories exported by
this security model cannot
1378 interact with other unix tools
. "none" security model is same as
1379 passthrough except the sever won
't report failures if it fails to
1380 set file attributes like ownership. Security model is mandatory only
1381 for local fsdriver. Other fsdrivers (like proxy) don't take security
1382 model as a parameter
.
1383 @item writeout
=@
var{writeout
}
1384 This is an optional argument
. The only supported value is
"immediate".
1385 This means that host page cache will be used to read and write data but
1386 write notification will be sent to the guest only when the data has been
1387 reported as written by the storage subsystem
.
1389 Enables exporting
9p share as a readonly mount
for guests
. By
default
1390 read
-write access is given
.
1391 @item socket
=@
var{socket
}
1392 Enables proxy filesystem driver to use passed socket file
for
1393 communicating with virtfs
-proxy
-helper(1). Usually a helper like libvirt
1394 will create socketpair and pass one of the fds as sock_fd
.
1396 Enables proxy filesystem driver to use passed
'sock_fd' as the socket
1397 descriptor
for interfacing with virtfs
-proxy
-helper(1).
1398 @item fmode
=@
var{fmode
}
1399 Specifies the
default mode
for newly created files on the host
. Works only
1400 with security models
"mapped-xattr" and
"mapped-file".
1401 @item dmode
=@
var{dmode
}
1402 Specifies the
default mode
for newly created directories on the host
. Works
1403 only with security models
"mapped-xattr" and
"mapped-file".
1404 @item mount_tag
=@
var{mount_tag
}
1405 Specifies the tag name to be used by the guest to mount
this export point
.
1409 DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth
,
1410 "-virtfs_synth Create synthetic file system image\n",
1414 @findex
-virtfs_synth
1415 Create synthetic file system image
. Note that
this option is now deprecated
.
1416 Please use @code
{-fsdev synth
} and @code
{-device virtio
-9p
-...} instead
.
1419 DEF("iscsi", HAS_ARG
, QEMU_OPTION_iscsi
,
1420 "-iscsi [user=user][,password=password]\n"
1421 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1422 " [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1423 " [,timeout=timeout]\n"
1424 " iSCSI session parameters\n", QEMU_ARCH_ALL
)
1429 Configure iSCSI session parameters
.
1437 DEFHEADING(USB options
:)
1442 DEF("usb", 0, QEMU_OPTION_usb
,
1443 "-usb enable on-board USB host controller (if not enabled by default)\n",
1448 Enable USB emulation on machine types with an on
-board USB host
controller (if
1449 not enabled by
default). Note that on
-board USB host controllers may not
1450 support USB
3.0. In
this case @option
{-device qemu
-xhci
} can be used instead
1451 on machines with PCI
.
1454 DEF("usbdevice", HAS_ARG
, QEMU_OPTION_usbdevice
,
1455 "-usbdevice name add the host or guest USB device 'name'\n",
1459 @item
-usbdevice @
var{devname
}
1461 Add the USB device @
var{devname
}. Note that
this option is deprecated
,
1462 please use @code
{-device usb
-...} instead
. @xref
{usb_devices
}.
1467 Virtual Mouse
. This will
override the PS
/2 mouse emulation when activated
.
1470 Pointer device that uses absolute
coordinates (like a touchscreen
). This
1471 means QEMU is able to report the mouse position without having to grab the
1472 mouse
. Also overrides the PS
/2 mouse emulation when activated
.
1475 Braille device
. This will use BrlAPI to display the braille output on a real
1486 DEFHEADING(Display options
:)
1491 DEF("display", HAS_ARG
, QEMU_OPTION_display
,
1492 "-display spice-app[,gl=on|off]\n"
1493 "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
1494 " [,window_close=on|off][,gl=on|core|es|off]\n"
1495 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1496 "-display vnc=<display>[,<optargs>]\n"
1497 "-display curses[,charset=<encoding>]\n"
1499 "-display egl-headless[,rendernode=<file>]"
1500 " select display type\n"
1501 "The default display is equivalent to\n"
1502 #
if defined(CONFIG_GTK
)
1503 "\t\"-display gtk\"\n"
1504 #elif
defined(CONFIG_SDL
)
1505 "\t\"-display sdl\"\n"
1506 #elif
defined(CONFIG_COCOA
)
1507 "\t\"-display cocoa\"\n"
1508 #elif
defined(CONFIG_VNC
)
1509 "\t\"-vnc localhost:0,to=99,id=default\"\n"
1511 "\t\"-display none\"\n"
1515 @item
-display @
var{type
}
1517 Select type of display to use
. This option is a replacement
for the
1518 old style
-sdl
/-curses
/... options
. Valid values
for @
var{type
} are
1521 Display video output via
SDL (usually
in a separate graphics
1522 window
; see the SDL documentation
for other possibilities
).
1524 Display video output via curses
. For graphics device models which
1525 support a text mode
, QEMU can display
this output
using a
1526 curses
/ncurses
interface. Nothing is displayed when the graphics
1527 device is
in graphical mode or
if the graphics device does not support
1528 a text mode
. Generally only the VGA device models support text mode
.
1529 The font charset used by the guest can be specified with the
1530 @code
{charset
} option
, for example @code
{charset
=CP850
} for IBM CP850
1531 encoding
. The
default is @code
{CP437
}.
1533 Do not display video output
. The guest will still see an emulated
1534 graphics card
, but its output will not be displayed to the QEMU
1535 user
. This option differs from the
-nographic option
in that it
1536 only affects what is done with video output
; -nographic also changes
1537 the destination of the serial and parallel port data
.
1539 Display video output
in a GTK window
. This
interface provides drop
-down
1540 menus and other UI elements to configure and control the VM during
1543 Start a VNC server on display
<arg
>
1545 Offload all OpenGL operations to a local DRI device
. For any graphical display
,
1546 this display needs to be paired with either VNC or SPICE displays
.
1548 Start QEMU as a Spice server and launch the
default Spice client
1549 application
. The Spice server will redirect the serial consoles and
1550 QEMU monitors
. (Since
4.0)
1554 DEF("nographic", 0, QEMU_OPTION_nographic
,
1555 "-nographic disable graphical output and redirect serial I/Os to console\n",
1560 Normally
, if QEMU is compiled with graphical window support
, it displays
1561 output such as guest graphics
, guest console
, and the QEMU monitor
in a
1562 window
. With
this option
, you can totally disable graphical output so
1563 that QEMU is a simple command line application
. The emulated serial port
1564 is redirected on the console and muxed with the
monitor (unless
1565 redirected elsewhere explicitly
). Therefore
, you can still use QEMU to
1566 debug a Linux kernel with a serial console
. Use @key
{C
-a h
} for help on
1567 switching between the console and monitor
.
1570 DEF("curses", 0, QEMU_OPTION_curses
,
1571 "-curses shorthand for -display curses\n",
1576 Normally
, if QEMU is compiled with graphical window support
, it displays
1577 output such as guest graphics
, guest console
, and the QEMU monitor
in a
1578 window
. With
this option
, QEMU can display the VGA output when
in text
1579 mode
using a curses
/ncurses
interface. Nothing is displayed
in graphical
1583 DEF("alt-grab", 0, QEMU_OPTION_alt_grab
,
1584 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1589 Use Ctrl
-Alt
-Shift to grab
mouse (instead of Ctrl
-Alt
). Note that
this also
1590 affects the special
keys (for fullscreen
, monitor
-mode switching
, etc
).
1593 DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab
,
1594 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1599 Use Right
-Ctrl to grab
mouse (instead of Ctrl
-Alt
). Note that
this also
1600 affects the special
keys (for fullscreen
, monitor
-mode switching
, etc
).
1603 DEF("no-quit", 0, QEMU_OPTION_no_quit
,
1604 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL
)
1608 Disable SDL window close capability
.
1611 DEF("sdl", 0, QEMU_OPTION_sdl
,
1612 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL
)
1619 DEF("spice", HAS_ARG
, QEMU_OPTION_spice
,
1620 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1621 " [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1622 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1623 " [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n"
1624 " [,tls-ciphers=<list>]\n"
1625 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1626 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1627 " [,sasl][,password=<secret>][,disable-ticketing]\n"
1628 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1629 " [,jpeg-wan-compression=[auto|never|always]]\n"
1630 " [,zlib-glz-wan-compression=[auto|never|always]]\n"
1631 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
1632 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
1633 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1634 " [,gl=[on|off]][,rendernode=<file>]\n"
1636 " at least one of {port, tls-port} is mandatory\n",
1639 @item
-spice @
var{option
}[,@
var{option
}[,...]]
1641 Enable the spice remote desktop protocol
. Valid options are
1646 Set the TCP port spice is listening on
for plaintext channels
.
1649 Set the IP address spice is listening on
. Default is any address
.
1654 Force
using the specified IP version
.
1656 @item password
=<secret
>
1657 Set the password you need to authenticate
.
1660 Require that the client use SASL to authenticate with the spice
.
1661 The exact choice of authentication method used is controlled from the
1662 system
/ user
's SASL configuration file for the 'qemu
' service. This
1663 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1664 unprivileged user, an environment variable SASL_CONF_PATH can be used
1665 to make it search alternate locations for the service config.
1666 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1667 it is recommended that SASL always be combined with the 'tls
' and
1668 'x509
' settings to enable use of SSL and server certificates. This
1669 ensures a data encryption preventing compromise of authentication
1672 @item disable-ticketing
1673 Allow client connects without authentication.
1675 @item disable-copy-paste
1676 Disable copy paste between the client and the guest.
1678 @item disable-agent-file-xfer
1679 Disable spice-vdagent based file-xfer between the client and the guest.
1682 Set the TCP port spice is listening on for encrypted channels.
1684 @item x509-dir=<dir>
1685 Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1687 @item x509-key-file=<file>
1688 @itemx x509-key-password=<file>
1689 @itemx x509-cert-file=<file>
1690 @itemx x509-cacert-file=<file>
1691 @itemx x509-dh-key-file=<file>
1692 The x509 file names can also be configured individually.
1694 @item tls-ciphers=<list>
1695 Specify which ciphers to use.
1697 @item tls-channel=[main|display|cursor|inputs|record|playback]
1698 @itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1699 Force specific channel to be used with or without TLS encryption. The
1700 options can be specified multiple times to configure multiple
1701 channels. The special name "default" can be used to set the default
1702 mode. For channels which are not explicitly forced into one mode the
1703 spice client is allowed to pick tls/plaintext as he pleases.
1705 @item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1706 Configure image compression (lossless).
1707 Default is auto_glz.
1709 @item jpeg-wan-compression=[auto|never|always]
1710 @itemx zlib-glz-wan-compression=[auto|never|always]
1711 Configure wan image compression (lossy for slow links).
1714 @item streaming-video=[off|all|filter]
1715 Configure video stream detection. Default is off.
1717 @item agent-mouse=[on|off]
1718 Enable/disable passing mouse events via vdagent. Default is on.
1720 @item playback-compression=[on|off]
1721 Enable/disable audio stream compression (using celt 0.5.1). Default is on.
1723 @item seamless-migration=[on|off]
1724 Enable/disable spice seamless migration. Default is off.
1727 Enable/disable OpenGL context. Default is off.
1729 @item rendernode=<file>
1730 DRM render node for OpenGL rendering. If not specified, it will pick
1731 the first available. (Since 2.9)
1736 DEF("portrait", 0, QEMU_OPTION_portrait,
1737 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n",
1742 Rotate graphical output 90 deg left (only PXA LCD).
1745 DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1746 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n",
1749 @item -rotate @var{deg}
1751 Rotate graphical output some deg left (only PXA LCD).
1754 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
1755 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
1756 " select video card type\n", QEMU_ARCH_ALL)
1758 @item -vga @var{type}
1760 Select type of VGA card to emulate. Valid values for @var{type} are
1763 Cirrus Logic GD5446 Video card. All Windows versions starting from
1764 Windows 95 should recognize and use this graphic card. For optimal
1765 performances, use 16 bit color depth in the guest and the host OS.
1766 (This card was the default before QEMU 2.2)
1768 Standard VGA card with Bochs VBE extensions. If your guest OS
1769 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1770 to use high resolution modes (>= 1280x1024x16) then you should use
1771 this option. (This card is the default since QEMU 2.2)
1773 VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1774 recent XFree86/XOrg server or Windows guest with a driver for this
1777 QXL paravirtual graphic card. It is VGA compatible (including VESA
1778 2.0 VBE support). Works best with qxl guest drivers installed though.
1779 Recommended choice when using the spice protocol.
1781 (sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1782 sun4m machines and offers both 8-bit and 24-bit colour depths at a
1783 fixed resolution of 1024x768.
1785 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1786 for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1787 resolutions aimed at people wishing to run older Solaris versions.
1795 DEF("full-screen", 0, QEMU_OPTION_full_screen,
1796 "-full-screen start in full screen\n", QEMU_ARCH_ALL)
1799 @findex -full-screen
1800 Start in full screen.
1803 DEF("g", 1, QEMU_OPTION_g ,
1804 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n",
1805 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
1807 @item -g @var{width}x@var{height}[x@var{depth}]
1809 Set the initial graphical resolution and depth (PPC, SPARC only).
1812 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1813 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1815 @item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1817 Normally, if QEMU is compiled with graphical window support, it displays
1818 output such as guest graphics, guest console, and the QEMU monitor in a
1819 window. With this option, you can have QEMU listen on VNC display
1820 @var{display} and redirect the VGA display over the VNC session. It is
1821 very useful to enable the usb tablet device when using this option
1822 (option @option{-device usb-tablet}). When using the VNC display, you
1823 must use the @option{-k} parameter to set the keyboard layout if you are
1824 not using en-us. Valid syntax for the @var{display} is
1830 With this option, QEMU will try next available VNC @var{display}s, until the
1831 number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1832 available, e.g. port 5900+@var{display} is already used by another
1833 application. By default, to=0.
1835 @item @var{host}:@var{d}
1837 TCP connections will only be allowed from @var{host} on display @var{d}.
1838 By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1839 be omitted in which case the server will accept connections from any host.
1841 @item unix:@var{path}
1843 Connections will be allowed over UNIX domain sockets where @var{path} is the
1844 location of a unix socket to listen for connections on.
1848 VNC is initialized but not started. The monitor @code{change} command
1849 can be used to later start the VNC server.
1853 Following the @var{display} value there may be one or more @var{option} flags
1854 separated by commas. Valid options are
1860 Connect to a listening VNC client via a ``reverse'' connection. The
1861 client is specified by the @var{display}. For reverse network
1862 connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
1863 is a TCP port number, not a display number.
1867 Opens an additional TCP listening port dedicated to VNC Websocket connections.
1868 If a bare @var{websocket} option is given, the Websocket port is
1869 5700+@var{display}. An alternative port can be specified with the
1870 syntax @code{websocket}=@var{port}.
1872 If @var{host} is specified connections will only be allowed from this host.
1873 It is possible to control the websocket listen address independently, using
1874 the syntax @code{websocket}=@var{host}:@var{port}.
1876 If no TLS credentials are provided, the websocket connection runs in
1877 unencrypted mode. If TLS credentials are provided, the websocket connection
1878 requires encrypted client connections.
1882 Require that password based authentication is used for client connections.
1884 The password must be set separately using the @code{set_password} command in
1885 the @ref{pcsys_monitor}. The syntax to change your password is:
1886 @code{set_password <protocol> <password>} where <protocol> could be either
1889 If you would like to change <protocol> password expiration, you should use
1890 @code{expire_password <protocol> <expiration-time>} where expiration time could
1891 be one of the following options: now, never, +seconds or UNIX time of
1892 expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
1893 to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
1896 You can also use keywords "now" or "never" for the expiration time to
1897 allow <protocol> password to expire immediately or never expire.
1899 @item tls-creds=@var{ID}
1901 Provides the ID of a set of TLS credentials to use to secure the
1902 VNC server. They will apply to both the normal VNC server socket
1903 and the websocket socket (if enabled). Setting TLS credentials
1904 will cause the VNC server socket to enable the VeNCrypt auth
1905 mechanism. The credentials should have been previously created
1906 using the @option{-object tls-creds} argument.
1908 @item tls-authz=@var{ID}
1910 Provides the ID of the QAuthZ authorization object against which
1911 the client's x509 distinguished name will validated
. This object is
1912 only resolved at time of use
, so can be deleted and recreated on the
1913 fly
while the VNC server is active
. If missing
, it will
default
1918 Require that the client use SASL to authenticate with the VNC server
.
1919 The exact choice of authentication method used is controlled from the
1920 system
/ user
's SASL configuration file for the 'qemu
' service. This
1921 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1922 unprivileged user, an environment variable SASL_CONF_PATH can be used
1923 to make it search alternate locations for the service config.
1924 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1925 it is recommended that SASL always be combined with the 'tls
' and
1926 'x509
' settings to enable use of SSL and server certificates. This
1927 ensures a data encryption preventing compromise of authentication
1928 credentials. See the @ref{vnc_security} section for details on using
1929 SASL authentication.
1931 @item sasl-authz=@var{ID}
1933 Provides the ID of the QAuthZ authorization object against which
1934 the client's SASL username will validated
. This object is
1935 only resolved at time of use
, so can be deleted and recreated on the
1936 fly
while the VNC server is active
. If missing
, it will
default
1941 Legacy method
for enabling authorization of clients against the
1942 x509 distinguished name and SASL username
. It results
in the creation
1943 of two @code
{authz
-list
} objects with IDs of @code
{vnc
.username
} and
1944 @code
{vnc
.x509dname
}. The rules
for these objects must be configured
1945 with the HMP ACL commands
.
1947 This option is deprecated and should no longer be used
. The
new
1948 @option
{sasl
-authz
} and @option
{tls
-authz
} options are a
1953 Enable lossy compression
methods (gradient
, JPEG
, ...). If
this
1954 option is set
, VNC client may receive lossy framebuffer updates
1955 depending on its encoding settings
. Enabling
this option can save
1956 a lot of bandwidth at the expense of quality
.
1960 Disable adaptive encodings
. Adaptive encodings are enabled by
default.
1961 An adaptive encoding will
try to detect frequently updated screen regions
,
1962 and send updates
in these regions
using a lossy
encoding (like JPEG
).
1963 This can be really helpful to save bandwidth when playing videos
. Disabling
1964 adaptive encodings restores the original
static behavior of encodings
1967 @item share
=[allow
-exclusive|force
-shared|ignore
]
1969 Set display sharing policy
. 'allow-exclusive' allows clients to ask
1970 for exclusive access
. As suggested by the rfb spec
this is
1971 implemented by dropping other connections
. Connecting multiple
1972 clients
in parallel requires all clients asking
for a shared session
1973 (vncviewer
: -shared
switch). This is the
default. 'force-shared'
1974 disables exclusive client access
. Useful
for shared desktop sessions
,
1975 where you don
't want someone forgetting specify -shared disconnect
1976 everybody else. 'ignore
' completely ignores the shared flag and
1977 allows everybody connect unconditionally. Doesn't conform to the rfb
1978 spec but is traditional QEMU behavior
.
1982 Set keyboard delay
, for key down and key up events
, in milliseconds
.
1983 Default is
10. Keyboards are low
-bandwidth devices
, so
this slowdown
1984 can help the device and guest to keep up and not lose events
in case
1985 events are arriving
in bulk
. Possible causes
for the latter are flaky
1986 network connections
, or scripts
for automated testing
.
1988 @item audiodev
=@
var{audiodev
}
1990 Use the specified @
var{audiodev
} when the VNC client requests audio
1991 transmission
. When not
using an
-audiodev argument
, this option must
1992 be omitted
, otherwise is must be present and specify a valid audiodev
.
2000 ARCHHEADING(, QEMU_ARCH_I386
)
2002 ARCHHEADING(i386 target only
:, QEMU_ARCH_I386
)
2007 DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack
,
2008 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n",
2013 Use it when installing Windows
2000 to avoid a disk full bug
. After
2014 Windows
2000 is installed
, you no longer need
this option (this option
2015 slows down the IDE transfers
).
2018 DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk
,
2019 "-no-fd-bootchk disable boot signature checking for floppy disks\n",
2022 @item
-no
-fd
-bootchk
2023 @findex
-no
-fd
-bootchk
2024 Disable boot signature checking
for floppy disks
in BIOS
. May
2025 be needed to boot from old floppy disks
.
2028 DEF("no-acpi", 0, QEMU_OPTION_no_acpi
,
2029 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM
)
2033 Disable
ACPI (Advanced Configuration and Power Interface
) support
. Use
2034 it
if your guest OS complains about ACPI
problems (PC target machine
2038 DEF("no-hpet", 0, QEMU_OPTION_no_hpet
,
2039 "-no-hpet disable HPET\n", QEMU_ARCH_I386
)
2043 Disable HPET support
.
2046 DEF("acpitable", HAS_ARG
, QEMU_OPTION_acpitable
,
2047 "-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"
2048 " ACPI table description\n", QEMU_ARCH_I386
)
2050 @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
}]...]
2052 Add ACPI table with specified header fields and context from specified files
.
2053 For file
=, take whole ACPI table from the specified files
, including all
2054 ACPI
headers (possible overridden by other options
).
2055 For data
=, only data
2056 portion of the table is used
, all header information is specified
in the
2058 If a SLIC table is supplied to QEMU
, then the SLIC
's oem_id and oem_table_id
2059 fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
2060 to ensure the field matches required by the Microsoft SLIC spec and the ACPI
2064 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2065 "-smbios file=binary\n"
2066 " load SMBIOS entry from binary file\n"
2067 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2069 " specify SMBIOS type 0 fields\n"
2070 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2071 " [,uuid=uuid][,sku=str][,family=str]\n"
2072 " specify SMBIOS type 1 fields\n"
2073 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2074 " [,asset=str][,location=str]\n"
2075 " specify SMBIOS type 2 fields\n"
2076 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2078 " specify SMBIOS type 3 fields\n"
2079 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2080 " [,asset=str][,part=str]\n"
2081 " specify SMBIOS type 4 fields\n"
2082 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2083 " [,asset=str][,part=str][,speed=%d]\n"
2084 " specify SMBIOS type 17 fields\n",
2085 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2087 @item -smbios file=@var{binary}
2089 Load SMBIOS entry from binary file.
2091 @item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
2092 Specify SMBIOS type 0 fields
2094 @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}]
2095 Specify SMBIOS type 1 fields
2097 @item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}]
2098 Specify SMBIOS type 2 fields
2100 @item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
2101 Specify SMBIOS type 3 fields
2103 @item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
2104 Specify SMBIOS type 4 fields
2106 @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}]
2107 Specify SMBIOS type 17 fields
2115 DEFHEADING(Network options:)
2120 DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2122 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n"
2123 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2124 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2125 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2126 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2128 "[,smb=dir[,smbserver=addr]]\n"
2130 " configure a user mode network backend with ID 'str
',\n"
2131 " its DHCP server and optional services\n"
2134 "-netdev tap,id=str,ifname=name\n"
2135 " configure a host TAP network backend with ID 'str
'\n"
2137 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2138 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2139 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2141 " configure a host TAP network backend with ID 'str
'\n"
2142 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2143 " use network scripts 'file
' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2144 " to configure it and 'dfile
' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2145 " to deconfigure it\n"
2146 " use '[down
]script
=no
' to disable script execution\n"
2147 " use network helper 'helper
' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2149 " use 'fd
=h
' to connect to an already opened TAP interface\n"
2150 " use 'fds
=x
:y
:...:z
' to connect to already opened multiqueue capable TAP interfaces\n"
2151 " use 'sndbuf
=nbytes
' to limit the size of the send buffer (the\n"
2152 " default is disabled 'sndbuf
=0' to enable flow control set 'sndbuf
=1048576')\n"
2153 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2154 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2155 " use vhost=on to enable experimental in kernel accelerator\n"
2156 " (only has effect for virtio guests which use MSIX)\n"
2157 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2158 " use 'vhostfd
=h
' to connect to an already opened vhost net device\n"
2159 " use 'vhostfds
=x
:y
:...:z to connect to multiple already opened vhost net devices
\n"
2160 " use
'queues=n' to specify the number of queues to be created
for multiqueue TAP
\n"
2161 " use
'poll-us=n' to speciy the maximum number of microseconds that could be
\n"
2162 " spent on busy polling
for vhost net
\n"
2163 "-netdev bridge
,id
=str
[,br
=bridge
][,helper
=helper
]\n"
2164 " configure a host TAP network backend with ID
'str' that is
\n"
2165 " connected to a
bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2166 " using the program
'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2169 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2170 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n"
2171 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n"
2172 " [,rxcookie=rxcookie][,offset=offset]\n"
2173 " configure a network backend with ID 'str
' connected to\n"
2174 " an Ethernet over L2TPv3 pseudowire.\n"
2175 " Linux kernel 3.3+ as well as most routers can talk\n"
2176 " L2TPv3. This transport allows connecting a VM to a VM,\n"
2177 " VM to a router and even VM to Host. It is a nearly-universal\n"
2178 " standard (RFC3391). Note - this implementation uses static\n"
2179 " pre-configured tunnels (same as the Linux kernel).\n"
2180 " use 'src
=' to specify source address\n"
2181 " use 'dst
=' to specify destination address\n"
2182 " use 'udp
=on
' to specify udp encapsulation\n"
2183 " use 'srcport
=' to specify source udp port\n"
2184 " use 'dstport
=' to specify destination udp port\n"
2185 " use 'ipv6
=on
' to force v6\n"
2186 " L2TPv3 uses cookies to prevent misconfiguration as\n"
2187 " well as a weak security measure\n"
2188 " use 'rxcookie
=0x012345678' to specify a rxcookie\n"
2189 " use 'txcookie
=0x012345678' to specify a txcookie\n"
2190 " use 'cookie64
=on
' to set cookie size to 64 bit, otherwise 32\n"
2191 " use 'counter
=off
' to force a 'cut
-down
' L2TPv3 with no counter\n"
2192 " use 'pincounter
=on
' to work around broken counter handling in peer\n"
2193 " use 'offset
=X
' to add an extra offset between header and data\n"
2195 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2196 " configure a network backend to connect to another network\n"
2197 " using a socket connection\n"
2198 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2199 " configure a network backend to connect to a multicast maddr and port\n"
2200 " use 'localaddr
=addr
' to specify the host address to send packets from\n"
2201 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2202 " configure a network backend to connect to another network\n"
2203 " using an UDP tunnel\n"
2205 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2206 " configure a network backend to connect to port 'n
' of a vde switch\n"
2207 " running on host and listening for incoming connections on 'socketpath
'.\n"
2208 " Use group 'groupname
' and mode 'octalmode
' to change default\n"
2209 " ownership and permissions for communication port.\n"
2211 #ifdef CONFIG_NETMAP
2212 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2213 " attach to the existing netmap-enabled network interface 'name
', or to a\n"
2214 " VALE port (created on the fly) called 'name
' ('nmname
' is name of the \n"
2215 " netmap device, defaults to '/dev
/netmap
')\n"
2218 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2219 " configure a vhost-user network, backed by a chardev 'dev
'\n"
2221 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2222 " configure a hub port on the hub with ID 'n
'\n", QEMU_ARCH_ALL)
2223 DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2234 #ifdef CONFIG_NETMAP
2240 "socket][,option][,...][mac=macaddr]\n"
2241 " initialize an on-board / default host NIC (using MAC address\n"
2242 " macaddr) and connect it to the given host network backend\n"
2243 "-nic none use it alone to have zero network devices (the default is to\n"
2244 " provided a 'user
' network connection)\n",
2246 DEF("net", HAS_ARG, QEMU_OPTION_net,
2247 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2248 " configure or create an on-board (or machine default) NIC and\n"
2249 " connect it to hub 0 (please use -nic unless you need a hub)\n"
2259 #ifdef CONFIG_NETMAP
2262 "socket][,option][,option][,...]\n"
2263 " old way to initialize a host network interface\n"
2264 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2266 @item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
2268 This option is a shortcut for configuring both the on-board (default) guest
2269 NIC hardware and the host network backend in one go. The host backend options
2270 are the same as with the corresponding @option{-netdev} options below.
2271 The guest NIC model can be set with @option{model=@var{modelname}}.
2272 Use @option{model=help} to list the available device types.
2273 The hardware MAC address can be set with @option{mac=@var{macaddr}}.
2275 The following two example do exactly the same, to show how @option{-nic} can
2276 be used to shorten the command line length (note that the e1000 is the default
2277 on i386, so the @option{model=e1000} parameter could even be omitted here, too):
2279 @value{qemu_system} -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2280 @value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2284 Indicate that no network devices should be configured. It is used to override
2285 the default configuration (default NIC with ``user'' host network backend)
2286 which is activated if no other networking options are provided.
2288 @item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
2290 Configure user mode host network backend which requires no administrator
2291 privilege to run. Valid options are:
2295 Assign symbolic name for use in monitor commands.
2297 @item ipv4=on|off and ipv6=on|off
2298 Specify that either IPv4 or IPv6 must be enabled. If neither is specified
2299 both protocols are enabled.
2301 @item net=@var{addr}[/@var{mask}]
2302 Set IP network address the guest will see. Optionally specify the netmask,
2303 either in the form a.b.c.d or as number of valid top-most bits. Default is
2306 @item host=@var{addr}
2307 Specify the guest-visible address of the host. Default is the 2nd IP in the
2308 guest network, i.e. x.x.x.2.
2310 @item ipv6-net=@var{addr}[/@var{int}]
2311 Set IPv6 network address the guest will see (default is fec0::/64). The
2312 network prefix is given in the usual hexadecimal IPv6 address
2313 notation. The prefix size is optional, and is given as the number of
2314 valid top-most bits (default is 64).
2316 @item ipv6-host=@var{addr}
2317 Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2318 the guest network, i.e. xxxx::2.
2320 @item restrict=on|off
2321 If this option is enabled, the guest will be isolated, i.e. it will not be
2322 able to contact the host and no guest IP packets will be routed over the host
2323 to the outside. This option does not affect any explicitly set forwarding rules.
2325 @item hostname=@var{name}
2326 Specifies the client hostname reported by the built-in DHCP server.
2328 @item dhcpstart=@var{addr}
2329 Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2330 is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2332 @item dns=@var{addr}
2333 Specify the guest-visible address of the virtual nameserver. The address must
2334 be different from the host address. Default is the 3rd IP in the guest network,
2337 @item ipv6-dns=@var{addr}
2338 Specify the guest-visible address of the IPv6 virtual nameserver. The address
2339 must be different from the host address. Default is the 3rd IP in the guest
2340 network, i.e. xxxx::3.
2342 @item dnssearch=@var{domain}
2343 Provides an entry for the domain-search list sent by the built-in
2344 DHCP server. More than one domain suffix can be transmitted by specifying
2345 this option multiple times. If supported, this will cause the guest to
2346 automatically try to append the given domain suffix(es) in case a domain name
2347 can not be resolved.
2351 @value{qemu_system} -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2354 @item domainname=@var{domain}
2355 Specifies the client domain name reported by the built-in DHCP server.
2357 @item tftp=@var{dir}
2358 When using the user mode network stack, activate a built-in TFTP
2359 server. The files in @var{dir} will be exposed as the root of a TFTP server.
2360 The TFTP client on the guest must be configured in binary mode (use the command
2361 @code{bin} of the Unix TFTP client).
2363 @item tftp-server-name=@var{name}
2364 In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
2365 66). This can be used to advise the guest to load boot files or configurations
2366 from a different server than the host address.
2368 @item bootfile=@var{file}
2369 When using the user mode network stack, broadcast @var{file} as the BOOTP
2370 filename. In conjunction with @option{tftp}, this can be used to network boot
2371 a guest from a local directory.
2373 Example (using pxelinux):
2375 @value{qemu_system} -hda linux.img -boot n -device e1000,netdev=n1 \
2376 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2379 @item smb=@var{dir}[,smbserver=@var{addr}]
2380 When using the user mode network stack, activate a built-in SMB
2381 server so that Windows OSes can access to the host files in @file{@var{dir}}
2382 transparently. The IP address of the SMB server can be set to @var{addr}. By
2383 default the 4th IP in the guest network is used, i.e. x.x.x.4.
2385 In the guest Windows OS, the line:
2389 must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2390 or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2392 Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2394 Note that a SAMBA server must be installed on the host OS.
2396 @item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2397 Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2398 the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2399 @var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2400 given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2401 be bound to a specific host interface. If no connection type is set, TCP is
2402 used. This option can be given multiple times.
2404 For example, to redirect host X11 connection from screen 1 to guest
2405 screen 0, use the following:
2409 @value{qemu_system} -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2410 # this host xterm should open in the guest X11 server
2414 To redirect telnet connections from host port 5555 to telnet port on
2415 the guest, use the following:
2419 @value{qemu_system} -nic user,hostfwd=tcp::5555-:23
2420 telnet localhost 5555
2423 Then when you use on the host @code{telnet localhost 5555}, you
2424 connect to the guest telnet server.
2426 @item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2427 @itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2428 Forward guest TCP connections to the IP address @var{server} on port @var{port}
2429 to the character device @var{dev} or to a program executed by @var{cmd:command}
2430 which gets spawned for each connection. This option can be given multiple times.
2432 You can either use a chardev directly and have that one used throughout QEMU's
2433 lifetime
, like
in the following example
:
2436 # open
10.10.1.1:4321 on bootup
, connect
10.0.2.100:1234 to it whenever
2437 # the guest accesses it
2438 @value
{qemu_system
} -nic user
,guestfwd
=tcp
:10.0.2.100:1234-tcp
:10.10.1.1:4321
2441 Or you can execute a command on every TCP connection established by the guest
,
2442 so that QEMU behaves similar to an inetd process
for that virtual server
:
2445 # call
"netcat 10.10.1.1 4321" on every TCP connection to
10.0.2.100:1234
2446 # and connect the TCP stream to its stdin
/stdout
2447 @value
{qemu_system
} -nic
'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2452 @item
-netdev tap
,id
=@
var{id
}[,fd
=@
var{h
}][,ifname
=@
var{name
}][,script
=@
var{file
}][,downscript
=@
var{dfile
}][,br
=@
var{bridge
}][,helper
=@
var{helper
}]
2453 Configure a host TAP network backend with ID @
var{id
}.
2455 Use the network script @
var{file
} to configure it and the network script
2456 @
var{dfile
} to deconfigure it
. If @
var{name
} is not provided
, the OS
2457 automatically provides one
. The
default network configure script is
2458 @file
{/etc
/qemu
-ifup
} and the
default network deconfigure script is
2459 @file
{/etc
/qemu
-ifdown
}. Use @option
{script
=no
} or @option
{downscript
=no
}
2460 to disable script execution
.
2462 If running QEMU as an unprivileged user
, use the network helper
2463 @
var{helper
} to configure the TAP
interface and attach it to the bridge
.
2464 The
default network helper executable is @file
{/path
/to
/qemu
-bridge
-helper
}
2465 and the
default bridge device is @file
{br0
}.
2467 @option
{fd
}=@
var{h
} can be used to specify the handle of an already
2468 opened host TAP
interface.
2473 #launch a QEMU instance with the
default network script
2474 @value
{qemu_system
} linux
.img
-nic tap
2478 #launch a QEMU instance with two NICs
, each one connected
2480 @value
{qemu_system
} linux
.img \
2481 -netdev tap
,id
=nd0
,ifname
=tap0
-device e1000
,netdev
=nd0 \
2482 -netdev tap
,id
=nd1
,ifname
=tap1
-device rtl8139
,netdev
=nd1
2486 #launch a QEMU instance with the
default network helper to
2487 #connect a TAP device to bridge br0
2488 @value
{qemu_system
} linux
.img
-device virtio
-net
-pci
,netdev
=n1 \
2489 -netdev tap
,id
=n1
,"helper=/path/to/qemu-bridge-helper"
2492 @item
-netdev bridge
,id
=@
var{id
}[,br
=@
var{bridge
}][,helper
=@
var{helper
}]
2493 Connect a host TAP network
interface to a host bridge device
.
2495 Use the network helper @
var{helper
} to configure the TAP
interface and
2496 attach it to the bridge
. The
default network helper executable is
2497 @file
{/path
/to
/qemu
-bridge
-helper
} and the
default bridge
2498 device is @file
{br0
}.
2503 #launch a QEMU instance with the
default network helper to
2504 #connect a TAP device to bridge br0
2505 @value
{qemu_system
} linux
.img
-netdev bridge
,id
=n1
-device virtio
-net
,netdev
=n1
2509 #launch a QEMU instance with the
default network helper to
2510 #connect a TAP device to bridge qemubr0
2511 @value
{qemu_system
} linux
.img
-netdev bridge
,br
=qemubr0
,id
=n1
-device virtio
-net
,netdev
=n1
2514 @item
-netdev socket
,id
=@
var{id
}[,fd
=@
var{h
}][,listen
=[@
var{host
}]:@
var{port
}][,connect
=@
var{host
}:@
var{port
}]
2516 This host network backend can be used to connect the guest
's network to
2517 another QEMU virtual machine using a TCP socket connection. If @option{listen}
2518 is specified, QEMU waits for incoming connections on @var{port}
2519 (@var{host} is optional). @option{connect} is used to connect to
2520 another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2521 specifies an already opened TCP socket.
2525 # launch a first QEMU instance
2526 @value{qemu_system} linux.img \
2527 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2528 -netdev socket,id=n1,listen=:1234
2529 # connect the network of this instance to the network of the first instance
2530 @value{qemu_system} linux.img \
2531 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2532 -netdev socket,id=n2,connect=127.0.0.1:1234
2535 @item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2537 Configure a socket host network backend to share the guest's network traffic
2538 with another QEMU virtual machines
using a UDP multicast socket
, effectively
2539 making a bus
for every QEMU with same multicast address @
var{maddr
} and @
var{port
}.
2543 Several QEMU can be running on different hosts and share same
bus (assuming
2544 correct multicast setup
for these hosts
).
2546 mcast support is compatible with User Mode
Linux (argument @option
{eth@
var{N
}=mcast
}), see
2547 @url
{http
://user-mode-linux.sf.net}.
2549 Use @option
{fd
=h
} to specify an already opened UDP multicast socket
.
2554 # launch one QEMU instance
2555 @value
{qemu_system
} linux
.img \
2556 -device e1000
,netdev
=n1
,mac
=52:54:00:12:34:56 \
2557 -netdev socket
,id
=n1
,mcast
=230.0.0.1:1234
2558 # launch another QEMU instance on same
"bus"
2559 @value
{qemu_system
} linux
.img \
2560 -device e1000
,netdev
=n2
,mac
=52:54:00:12:34:57 \
2561 -netdev socket
,id
=n2
,mcast
=230.0.0.1:1234
2562 # launch yet another QEMU instance on same
"bus"
2563 @value
{qemu_system
} linux
.img \
2564 -device e1000
,netdev
=n3
,mac
=52:54:00:12:34:58 \
2565 -netdev socket
,id
=n3
,mcast
=230.0.0.1:1234
2568 Example (User Mode Linux compat
.):
2570 # launch QEMU
instance (note mcast address selected is UML
's default)
2571 @value{qemu_system} linux.img \
2572 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2573 -netdev socket,id=n1,mcast=239.192.168.1:1102
2575 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2578 Example (send packets from host's
1.2.3.4):
2580 @value
{qemu_system
} linux
.img \
2581 -device e1000
,netdev
=n1
,mac
=52:54:00:12:34:56 \
2582 -netdev socket
,id
=n1
,mcast
=239.192.168.1:1102,localaddr
=1.2.3.4
2585 @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
}]
2586 Configure a L2TPv3 pseudowire host network backend
. L2TPv3 (RFC3391
) is a
2587 popular protocol to transport
Ethernet (and other Layer
2) data frames between
2588 two systems
. It is present
in routers
, firewalls and the Linux kernel
2589 (from version
3.3 onwards
).
2591 This transport allows a VM to communicate to another VM
, router or firewall directly
.
2594 @item src
=@
var{srcaddr
}
2595 source
address (mandatory
)
2596 @item dst
=@
var{dstaddr
}
2597 destination
address (mandatory
)
2599 select udp
encapsulation (default is ip
).
2600 @item srcport
=@
var{srcport
}
2602 @item dstport
=@
var{dstport
}
2603 destination udp port
.
2605 force v6
, otherwise defaults to v4
.
2606 @item rxcookie
=@
var{rxcookie
}
2607 @itemx txcookie
=@
var{txcookie
}
2608 Cookies are a weak form of security
in the l2tpv3 specification
.
2609 Their
function is mostly to prevent misconfiguration
. By
default they are
32
2612 Set cookie size to
64 bit instead of the
default 32
2614 Force a
'cut-down' L2TPv3 with no counter as
in
2615 draft
-mkonstan
-l2tpext
-keyed
-ipv6
-tunnel
-00
2617 Work around broken counter handling
in peer
. This may also help on
2618 networks which have packet reorder
.
2619 @item offset
=@
var{offset
}
2620 Add an extra offset between header and data
2623 For example
, to attach a VM running on host
4.3.2.1 via L2TPv3 to the bridge br
-lan
2624 on the remote Linux host
1.2.3.4:
2626 # Setup tunnel on linux host
using raw ip as encapsulation
2628 ip l2tp add tunnel remote
4.3.2.1 local
1.2.3.4 tunnel_id
1 peer_tunnel_id
1 \
2629 encap udp udp_sport
16384 udp_dport
16384
2630 ip l2tp add session tunnel_id
1 name vmtunnel0 session_id \
2631 0xFFFFFFFF peer_session_id
0xFFFFFFFF
2632 ifconfig vmtunnel0 mtu
1500
2633 ifconfig vmtunnel0 up
2634 brctl addif br
-lan vmtunnel0
2638 # launch QEMU instance
- if your network has reorder or is very lossy add
,pincounter
2640 @value
{qemu_system
} linux
.img
-device e1000
,netdev
=n1 \
2641 -netdev l2tpv3
,id
=n1
,src
=4.2.3.1,dst
=1.2.3.4,udp
,srcport
=16384,dstport
=16384,rxsession
=0xffffffff,txsession
=0xffffffff,counter
2645 @item
-netdev vde
,id
=@
var{id
}[,sock
=@
var{socketpath
}][,port
=@
var{n
}][,group
=@
var{groupname
}][,mode
=@
var{octalmode
}]
2646 Configure VDE backend to connect to PORT @
var{n
} of a vde
switch running on host and
2647 listening
for incoming connections on @
var{socketpath
}. Use GROUP @
var{groupname
}
2648 and MODE @
var{octalmode
} to change
default ownership and permissions
for
2649 communication port
. This option is only available
if QEMU has been compiled
2650 with vde support enabled
.
2655 vde_switch
-F
-sock
/tmp
/myswitch
2656 # launch QEMU instance
2657 @value
{qemu_system
} linux
.img
-nic vde
,sock
=/tmp
/myswitch
2660 @item
-netdev vhost
-user
,chardev
=@
var{id
}[,vhostforce
=on|off
][,queues
=n
]
2662 Establish a vhost
-user netdev
, backed by a chardev @
var{id
}. The chardev should
2663 be a unix domain socket backed one
. The vhost
-user uses a specifically defined
2664 protocol to pass vhost ioctl replacement messages to an application on the other
2665 end of the socket
. On non
-MSIX guests
, the feature can be forced with
2666 @
var{vhostforce
}. Use
'queues=@var{n}' to specify the number of queues to
2667 be created
for multiqueue vhost
-user
.
2671 qemu
-m
512 -object memory
-backend
-file
,id
=mem
,size
=512M
,mem
-path
=/hugetlbfs
,share
=on \
2672 -numa node
,memdev
=mem \
2673 -chardev socket
,id
=chr0
,path
=/path
/to
/socket \
2674 -netdev type
=vhost
-user
,id
=net0
,chardev
=chr0 \
2675 -device virtio
-net
-pci
,netdev
=net0
2678 @item
-netdev hubport
,id
=@
var{id
},hubid
=@
var{hubid
}[,netdev
=@
var{nd
}]
2680 Create a hub port on the emulated hub with ID @
var{hubid
}.
2682 The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2683 single netdev
. Alternatively
, you can also connect the hubport to another
2684 netdev with ID @
var{nd
} by
using the @option
{netdev
=@
var{nd
}} option
.
2686 @item
-net nic
[,netdev
=@
var{nd
}][,macaddr
=@
var{mac
}][,model
=@
var{type
}] [,name
=@
var{name
}][,addr
=@
var{addr
}][,vectors
=@
var{v
}]
2688 Legacy option to configure or create an on
-board (or machine
default) Network
2689 Interface
Card(NIC
) and connect it either to the emulated hub with ID
0 (i
.e
.
2690 the
default hub
), or to the netdev @
var{nd
}.
2691 The NIC is an e1000 by
default on the PC target
. Optionally
, the MAC address
2692 can be changed to @
var{mac
}, the device address set to @
var{addr
} (PCI cards
2693 only
), and a @
var{name
} can be assigned
for use
in monitor commands
.
2694 Optionally
, for PCI cards
, you can specify the number @
var{v
} of MSI
-X vectors
2695 that the card should have
; this option currently only affects virtio cards
; set
2696 @
var{v
} = 0 to disable MSI
-X
. If no @option
{-net
} option is specified
, a single
2697 NIC is created
. QEMU can emulate several different models of network card
.
2698 Use @code
{-net nic
,model
=help
} for a list of available devices
for your target
.
2700 @item
-net user|tap|bridge|socket|l2tpv3|vde
[,...][,name
=@
var{name
}]
2701 Configure a host network
backend (with the options corresponding to the same
2702 @option
{-netdev
} option
) and connect it to the emulated hub
0 (the
default
2703 hub
). Use @
var{name
} to specify the name of the hub port
.
2711 DEFHEADING(Character device options
:)
2713 DEF("chardev", HAS_ARG
, QEMU_OPTION_chardev
,
2715 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2716 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2717 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2718 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
2719 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2720 " [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2721 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2722 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2723 " [,logfile=PATH][,logappend=on|off]\n"
2724 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2725 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2726 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2727 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2728 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2729 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2731 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2732 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2734 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2735 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2737 #ifdef CONFIG_BRLAPI
2738 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2740 #
if defined(__linux__
) ||
defined(__sun__
) ||
defined(__FreeBSD__
) \
2741 ||
defined(__NetBSD__
) ||
defined(__OpenBSD__
) ||
defined(__DragonFly__
)
2742 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2743 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2745 #
if defined(__linux__
) ||
defined(__FreeBSD__
) ||
defined(__DragonFly__
)
2746 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2747 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2749 #
if defined(CONFIG_SPICE
)
2750 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2751 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2758 The general form of a character device option is
:
2760 @item
-chardev @
var{backend
},id
=@
var{id
}[,mux
=on|off
][,@
var{options
}]
2781 The specific backend will determine the applicable options
.
2783 Use @code
{-chardev help
} to print all available chardev backend types
.
2785 All devices must have an id
, which can be any string up to
127 characters long
.
2786 It is used to uniquely identify
this device
in other command line directives
.
2788 A character device may be used
in multiplexing mode by multiple front
-ends
.
2789 Specify @option
{mux
=on
} to enable
this mode
.
2790 A multiplexer is a
"1:N" device
, and
here the
"1" end is your specified chardev
2791 backend
, and the
"N" end is the various parts of QEMU that can talk to a chardev
.
2792 If you create a chardev with @option
{id
=myid
} and @option
{mux
=on
}, QEMU will
2793 create a multiplexer with your specified ID
, and you can then configure multiple
2794 front ends to use that chardev ID
for their input
/output
. Up to four different
2795 front ends can be connected to a single multiplexed chardev
. (Without
2796 multiplexing enabled
, a chardev can only be used by a single front end
.)
2797 For instance you could use
this to allow a single stdio chardev to be used by
2798 two serial ports and the QEMU monitor
:
2801 -chardev stdio
,mux
=on
,id
=char0 \
2802 -mon chardev
=char0
,mode
=readline \
2803 -serial chardev
:char0 \
2804 -serial chardev
:char0
2807 You can have more than one multiplexer
in a system configuration
; for instance
2808 you could have a TCP port multiplexed between UART
0 and UART
1, and stdio
2809 multiplexed between the QEMU monitor and a parallel port
:
2812 -chardev stdio
,mux
=on
,id
=char0 \
2813 -mon chardev
=char0
,mode
=readline \
2814 -parallel chardev
:char0 \
2815 -chardev tcp
,...,mux
=on
,id
=char1 \
2816 -serial chardev
:char1 \
2817 -serial chardev
:char1
2820 When you
're using a multiplexed character device, some escape sequences are
2821 interpreted in the input. @xref{mux_keys, Keys in the character backend
2824 Note that some other command line options may implicitly create multiplexed
2825 character backends; for instance @option{-serial mon:stdio} creates a
2826 multiplexed stdio backend connected to the serial port and the QEMU monitor,
2827 and @option{-nographic} also multiplexes the console and the monitor to
2830 There is currently no support for multiplexing in the other direction
2831 (where a single QEMU front end takes input and output from multiple chardevs).
2833 Every backend supports the @option{logfile} option, which supplies the path
2834 to a file to record all data transmitted via the backend. The @option{logappend}
2835 option controls whether the log file will be truncated or appended to when
2840 The available backends are:
2843 @item -chardev null,id=@var{id}
2844 A void device. This device will not emit any data, and will drop any data it
2845 receives. The null backend does not take any options.
2847 @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}]
2849 Create a two-way stream socket, which can be either a TCP or a unix socket. A
2850 unix socket will be created if @option{path} is specified. Behaviour is
2851 undefined if TCP options are specified for a unix socket.
2853 @option{server} specifies that the socket shall be a listening socket.
2855 @option{nowait} specifies that QEMU should not block waiting for a client to
2856 connect to a listening socket.
2858 @option{telnet} specifies that traffic on the socket should interpret telnet
2861 @option{websocket} specifies that the socket uses WebSocket protocol for
2864 @option{reconnect} sets the timeout for reconnecting on non-server sockets when
2865 the remote end goes away. qemu will delay this many seconds and then attempt
2866 to reconnect. Zero disables reconnecting, and is the default.
2868 @option{tls-creds} requests enablement of the TLS protocol for encryption,
2869 and specifies the id of the TLS credentials to use for the handshake. The
2870 credentials must be previously created with the @option{-object tls-creds}
2873 @option{tls-auth} provides the ID of the QAuthZ authorization object against
2874 which the client's x509 distinguished name will be validated
. This object is
2875 only resolved at time of use
, so can be deleted and recreated on the fly
2876 while the chardev server is active
. If missing
, it will
default to denying
2879 TCP and unix socket options are given below
:
2883 @item TCP options
: port
=@
var{port
}[,host
=@
var{host
}][,to
=@
var{to
}][,ipv4
][,ipv6
][,nodelay
]
2885 @option
{host
} for a listening socket specifies the local address to be bound
.
2886 For a connecting socket species the remote host to connect to
. @option
{host
} is
2887 optional
for listening sockets
. If not specified it defaults to @code
{0.0.0.0}.
2889 @option
{port
} for a listening socket specifies the local port to be bound
. For a
2890 connecting socket specifies the port on the remote host to connect to
.
2891 @option
{port
} can be given as either a port number or a service name
.
2892 @option
{port
} is required
.
2894 @option
{to
} is only relevant to listening sockets
. If it is specified
, and
2895 @option
{port
} cannot be bound
, QEMU will attempt to bind to subsequent ports up
2896 to and including @option
{to
} until it succeeds
. @option
{to
} must be specified
2899 @option
{ipv4
} and @option
{ipv6
} specify that either IPv4 or IPv6 must be used
.
2900 If neither is specified the socket may use either protocol
.
2902 @option
{nodelay
} disables the Nagle algorithm
.
2904 @item unix options
: path
=@
var{path
}
2906 @option
{path
} specifies the local path of the unix socket
. @option
{path
} is
2911 @item
-chardev udp
,id
=@
var{id
}[,host
=@
var{host
}],port
=@
var{port
}[,localaddr
=@
var{localaddr
}][,localport
=@
var{localport
}][,ipv4
][,ipv6
]
2913 Sends all traffic from the guest to a remote host over UDP
.
2915 @option
{host
} specifies the remote host to connect to
. If not specified it
2916 defaults to @code
{localhost
}.
2918 @option
{port
} specifies the port on the remote host to connect to
. @option
{port
}
2921 @option
{localaddr
} specifies the local address to bind to
. If not specified it
2922 defaults to @code
{0.0.0.0}.
2924 @option
{localport
} specifies the local port to bind to
. If not specified any
2925 available local port will be used
.
2927 @option
{ipv4
} and @option
{ipv6
} specify that either IPv4 or IPv6 must be used
.
2928 If neither is specified the device may use either protocol
.
2930 @item
-chardev msmouse
,id
=@
var{id
}
2932 Forward QEMU
's emulated msmouse events to the guest. @option{msmouse} does not
2935 @item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
2937 Connect to a QEMU text console. @option{vc} may optionally be given a specific
2940 @option{width} and @option{height} specify the width and height respectively of
2941 the console, in pixels.
2943 @option{cols} and @option{rows} specify that the console be sized to fit a text
2944 console with the given dimensions.
2946 @item -chardev ringbuf,id=@var{id}[,size=@var{size}]
2948 Create a ring buffer with fixed size @option{size}.
2949 @var{size} must be a power of two and defaults to @code{64K}.
2951 @item -chardev file,id=@var{id},path=@var{path}
2953 Log all traffic received from the guest to a file.
2955 @option{path} specifies the path of the file to be opened. This file will be
2956 created if it does not already exist, and overwritten if it does. @option{path}
2959 @item -chardev pipe,id=@var{id},path=@var{path}
2961 Create a two-way connection to the guest. The behaviour differs slightly between
2962 Windows hosts and other hosts:
2964 On Windows, a single duplex pipe will be created at
2965 @file{\\.pipe\@option{path}}.
2967 On other hosts, 2 pipes will be created called @file{@option{path}.in} and
2968 @file{@option{path}.out}. Data written to @file{@option{path}.in} will be
2969 received by the guest. Data written by the guest can be read from
2970 @file{@option{path}.out}. QEMU will not create these fifos, and requires them to
2973 @option{path} forms part of the pipe path as described above. @option{path} is
2976 @item -chardev console,id=@var{id}
2978 Send traffic from the guest to QEMU's standard output
. @option
{console
} does not
2981 @option
{console
} is only available on Windows hosts
.
2983 @item
-chardev serial
,id
=@
var{id
},path
=@option
{path
}
2985 Send traffic from the guest to a serial device on the host
.
2987 On Unix hosts serial will actually accept any tty device
,
2988 not only serial lines
.
2990 @option
{path
} specifies the name of the serial device to open
.
2992 @item
-chardev pty
,id
=@
var{id
}
2994 Create a
new pseudo
-terminal on the host and connect to it
. @option
{pty
} does
2995 not take any options
.
2997 @option
{pty
} is not available on Windows hosts
.
2999 @item
-chardev stdio
,id
=@
var{id
}[,signal
=on|off
]
3000 Connect to standard input and standard output of the QEMU process
.
3002 @option
{signal
} controls
if signals are enabled on the terminal
, that includes
3003 exiting QEMU with the key sequence @key
{Control
-c
}. This option is enabled by
3004 default, use @option
{signal
=off
} to disable it
.
3006 @item
-chardev braille
,id
=@
var{id
}
3008 Connect to a local BrlAPI server
. @option
{braille
} does not take any options
.
3010 @item
-chardev tty
,id
=@
var{id
},path
=@
var{path
}
3012 @option
{tty
} is only available on Linux
, Sun
, FreeBSD
, NetBSD
, OpenBSD and
3013 DragonFlyBSD hosts
. It is an alias
for @option
{serial
}.
3015 @option
{path
} specifies the path to the tty
. @option
{path
} is required
.
3017 @item
-chardev parallel
,id
=@
var{id
},path
=@
var{path
}
3018 @itemx
-chardev parport
,id
=@
var{id
},path
=@
var{path
}
3020 @option
{parallel
} is only available on Linux
, FreeBSD and DragonFlyBSD hosts
.
3022 Connect to a local parallel port
.
3024 @option
{path
} specifies the path to the parallel port device
. @option
{path
} is
3027 @item
-chardev spicevmc
,id
=@
var{id
},debug
=@
var{debug
},name
=@
var{name
}
3029 @option
{spicevmc
} is only available when spice support is built
in.
3031 @option
{debug
} debug level
for spicevmc
3033 @option
{name
} name of spice channel to connect to
3035 Connect to a spice virtual machine channel
, such as vdiport
.
3037 @item
-chardev spiceport
,id
=@
var{id
},debug
=@
var{debug
},name
=@
var{name
}
3039 @option
{spiceport
} is only available when spice support is built
in.
3041 @option
{debug
} debug level
for spicevmc
3043 @option
{name
} name of spice port to connect to
3045 Connect to a spice port
, allowing a Spice client to handle the traffic
3046 identified by a
name (preferably a fqdn
).
3054 DEFHEADING(Bluetooth(R
) options
:)
3059 DEF("bt", HAS_ARG
, QEMU_OPTION_bt
, \
3060 "-bt hci,null dumb bluetooth HCI - doesn't respond to commands\n" \
3061 "-bt hci,host[:id]\n" \
3062 " use host's HCI with the given name\n" \
3063 "-bt hci[,vlan=n]\n" \
3064 " emulate a standard HCI in virtual scatternet 'n'\n" \
3065 "-bt vhci[,vlan=n]\n" \
3066 " add host computer to virtual scatternet 'n' using VHCI\n" \
3067 "-bt device:dev[,vlan=n]\n" \
3068 " emulate a bluetooth device 'dev' in scatternet 'n'\n",
3073 Defines the
function of the corresponding Bluetooth HCI
. -bt options
3074 are matched with the HCIs present
in the chosen machine type
. For
3075 example when emulating a machine with only one HCI built into it
, only
3076 the first @code
{-bt hci
[...]} option is valid and defines the HCI
's
3077 logic. The Transport Layer is decided by the machine type. Currently
3078 the machines @code{n800} and @code{n810} have one HCI and all other
3081 Note: This option and the whole bluetooth subsystem is considered as deprecated.
3082 If you still use it, please send a mail to @email{qemu-devel@@nongnu.org} where
3083 you describe your usecase.
3086 The following three types are recognized:
3090 (default) The corresponding Bluetooth HCI assumes no internal logic
3091 and will not respond to any HCI commands or emit events.
3093 @item -bt hci,host[:@var{id}]
3094 (@code{bluez} only) The corresponding HCI passes commands / events
3095 to / from the physical HCI identified by the name @var{id} (default:
3096 @code{hci0}) on the computer running QEMU. Only available on @code{bluez}
3097 capable systems like Linux.
3099 @item -bt hci[,vlan=@var{n}]
3100 Add a virtual, standard HCI that will participate in the Bluetooth
3101 scatternet @var{n} (default @code{0}). Similarly to @option{-net}
3102 VLANs, devices inside a bluetooth network @var{n} can only communicate
3103 with other devices in the same network (scatternet).
3106 @item -bt vhci[,vlan=@var{n}]
3107 (Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached
3108 to the host bluetooth stack instead of to the emulated target. This
3109 allows the host and target machines to participate in a common scatternet
3110 and communicate. Requires the Linux @code{vhci} driver installed. Can
3111 be used as following:
3114 @value{qemu_system} [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5
3117 @item -bt device:@var{dev}[,vlan=@var{n}]
3118 Emulate a bluetooth device @var{dev} and place it in network @var{n}
3119 (default @code{0}). QEMU can only emulate one type of bluetooth devices
3124 Virtual wireless keyboard implementing the HIDP bluetooth profile.
3134 DEFHEADING(TPM device options:)
3136 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3137 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3138 " use path to provide path to a character device; default is /dev/tpm0\n"
3139 " use cancel-path to provide path to TPM's cancel sysfs entry
; if\n"
3140 " not provided it will be searched
for in /sys
/class/misc
/tpm?
/device
\n"
3141 "-tpmdev emulator
,id
=id
,chardev
=dev
\n"
3142 " configure the TPM device
using chardev backend
\n",
3146 The general form of a TPM device option is:
3149 @item -tpmdev @var{backend},id=@var{id}[,@var{options}]
3152 The specific backend type will determine the applicable options.
3153 The @code{-tpmdev} option creates the TPM backend and requires a
3154 @code{-device} option that specifies the TPM frontend interface model.
3156 Use @code{-tpmdev help} to print all available TPM backend types.
3160 The available backends are:
3164 @item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path}
3166 (Linux-host only) Enable access to the host's TPM using the passthrough
3169 @option{path} specifies the path to the host's TPM device, i.e., on
3170 a Linux host this would be @code{/dev/tpm0}.
3171 @option{path} is optional and by default @code{/dev/tpm0} is used.
3173 @option{cancel-path} specifies the path to the host TPM device's sysfs
3174 entry allowing for cancellation of an ongoing TPM command.
3175 @option{cancel-path} is optional and by default QEMU will search for the
3178 Some notes about using the host's TPM with the passthrough driver:
3180 The TPM device accessed by the passthrough driver must not be
3181 used by any other application on the host.
3183 Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
3184 the VM's firmware (BIOS/UEFI) will not be able to initialize the
3185 TPM again and may therefore not show a TPM-specific menu that would
3186 otherwise allow the user to configure the TPM, e.g., allow the user to
3187 enable/disable or activate/deactivate the TPM.
3188 Further, if TPM ownership is released from within a VM then the host's TPM
3189 will get disabled and deactivated. To enable and activate the
3190 TPM again afterwards, the host has to be rebooted and the user is
3191 required to enter the firmware's menu to enable and activate the TPM.
3192 If the TPM is left disabled and/or deactivated most TPM commands will fail.
3194 To create a passthrough TPM use the following two options:
3196 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3198 Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
3199 @code{tpmdev=tpm0} in the device option.
3201 @item -tpmdev emulator,id=@var{id},chardev=@var{dev}
3203 (Linux-host only) Enable access to a TPM emulator using Unix domain socket based
3206 @option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
3208 To create a TPM emulator backend device with chardev socket backend:
3211 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3224 DEFHEADING(Linux/Multiboot boot specific:)
3227 When using these options, you can use a given Linux or Multiboot
3228 kernel without installing it in the disk image. It can be useful
3229 for easier testing of various kernels.
3234 DEF("kernel
", HAS_ARG, QEMU_OPTION_kernel, \
3235 "-kernel bzImage use
'bzImage' as kernel image
\n", QEMU_ARCH_ALL)
3237 @item -kernel @var{bzImage}
3239 Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
3240 or in multiboot format.
3243 DEF("append
", HAS_ARG, QEMU_OPTION_append, \
3244 "-append cmdline use
'cmdline' as kernel command line
\n", QEMU_ARCH_ALL)
3246 @item -append @var{cmdline}
3248 Use @var{cmdline} as kernel command line
3251 DEF("initrd
", HAS_ARG, QEMU_OPTION_initrd, \
3252 "-initrd file use
'file' as initial ram disk
\n", QEMU_ARCH_ALL)
3254 @item -initrd @var{file}
3256 Use @var{file} as initial ram disk.
3258 @item -initrd "@
var{file1
} arg
=foo
,@
var{file2
}"
3260 This syntax is only available with multiboot.
3262 Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
3266 DEF("dtb
", HAS_ARG, QEMU_OPTION_dtb, \
3267 "-dtb file use
'file' as device tree image
\n", QEMU_ARCH_ALL)
3269 @item -dtb @var{file}
3271 Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
3280 DEFHEADING(Debug/Expert options:)
3285 DEF("fw_cfg
", HAS_ARG, QEMU_OPTION_fwcfg,
3286 "-fw_cfg
[name
=]<name
>,file
=<file
>\n"
3287 " add named fw_cfg entry with contents from file
\n"
3288 "-fw_cfg
[name
=]<name
>,string
=<str
>\n"
3289 " add named fw_cfg entry with contents from string
\n",
3293 @item -fw_cfg [name=]@var{name},file=@var{file}
3295 Add named fw_cfg entry with contents from file @var{file}.
3297 @item -fw_cfg [name=]@var{name},string=@var{str}
3298 Add named fw_cfg entry with contents from string @var{str}.
3300 The terminating NUL character of the contents of @var{str} will not be
3301 included as part of the fw_cfg item data. To insert contents with
3302 embedded NUL characters, you have to use the @var{file} parameter.
3304 The fw_cfg entries are passed by QEMU through to the guest.
3308 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3310 creates an fw_cfg entry named opt/com.mycompany/blob with contents
3315 DEF("serial
", HAS_ARG, QEMU_OPTION_serial, \
3316 "-serial dev redirect the serial port to char device
'dev'\n",
3319 @item -serial @var{dev}
3321 Redirect the virtual serial port to host character device
3322 @var{dev}. The default device is @code{vc} in graphical mode and
3323 @code{stdio} in non graphical mode.
3325 This option can be used several times to simulate up to 4 serial
3328 Use @code{-serial none} to disable all serial ports.
3330 Available character devices are:
3332 @item vc[:@var{W}x@var{H}]
3333 Virtual console. Optionally, a width and height can be given in pixel with
3337 It is also possible to specify width or height in characters:
3342 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3344 No device is allocated.
3347 @item chardev:@var{id}
3348 Use a named character device defined with the @code{-chardev} option.
3350 [Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3351 parameters are set according to the emulated ones.
3352 @item /dev/parport@var{N}
3353 [Linux only, parallel port only] Use host parallel port
3354 @var{N}. Currently SPP and EPP parallel port features can be used.
3355 @item file:@var{filename}
3356 Write output to @var{filename}. No character can be read.
3358 [Unix only] standard input/output
3359 @item pipe:@var{filename}
3360 name pipe @var{filename}
3362 [Windows only] Use host serial port @var{n}
3363 @item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3364 This implements UDP Net Console.
3365 When @var{remote_host} or @var{src_ip} are not specified
3366 they default to @code{0.0.0.0}.
3367 When not using a specified @var{src_port} a random port is automatically chosen.
3369 If you just want a simple readonly console you can use @code{netcat} or
3370 @code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3371 @code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3372 will appear in the netconsole session.
3374 If you plan to send characters back via netconsole or you want to stop
3375 and start QEMU a lot of times, you should have QEMU use the same
3376 source port each time by using something like @code{-serial
3377 udp::4555@@:4556} to QEMU. Another approach is to use a patched
3378 version of netcat which can listen to a TCP port and send and receive
3379 characters via udp. If you have a patched version of netcat which
3380 activates telnet remote echo and single char transfer, then you can
3381 use the following options to set up a netcat redirector to allow
3382 telnet on port 5555 to access the QEMU port.
3385 -serial udp::4555@@:4556
3386 @item netcat options:
3387 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3388 @item telnet options:
3392 @item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3393 The TCP Net Console has two modes of operation. It can send the serial
3394 I/O to a location or wait for a connection from a location. By default
3395 the TCP Net Console is sent to @var{host} at the @var{port}. If you use
3396 the @var{server} option QEMU will wait for a client socket application
3397 to connect to the port before continuing, unless the @code{nowait}
3398 option was specified. The @code{nodelay} option disables the Nagle buffering
3399 algorithm. The @code{reconnect} option only applies if @var{noserver} is
3400 set, if the connection goes down it will attempt to reconnect at the
3401 given interval. If @var{host} is omitted, 0.0.0.0 is assumed. Only
3402 one TCP connection at a time is accepted. You can use @code{telnet} to
3403 connect to the corresponding character device.
3405 @item Example to send tcp console to 192.168.0.2 port 4444
3406 -serial tcp:192.168.0.2:4444
3407 @item Example to listen and wait on port 4444 for connection
3408 -serial tcp::4444,server
3409 @item Example to not wait and listen on ip 192.168.0.100 port 4444
3410 -serial tcp:192.168.0.100:4444,server,nowait
3413 @item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3414 The telnet protocol is used instead of raw tcp sockets. The options
3415 work the same as if you had specified @code{-serial tcp}. The
3416 difference is that the port acts like a telnet server or client using
3417 telnet option negotiation. This will also allow you to send the
3418 MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3419 sequence. Typically in unix telnet you do it with Control-] and then
3420 type "send
break" followed by pressing the enter key.
3422 @item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
3423 The WebSocket protocol is used instead of raw tcp socket. The port acts as
3424 a WebSocket server. Client mode is not supported.
3426 @item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3427 A unix domain socket is used instead of a tcp socket. The option works the
3428 same as if you had specified @code{-serial tcp} except the unix domain socket
3429 @var{path} is used for connections.
3431 @item mon:@var{dev_string}
3432 This is a special option to allow the monitor to be multiplexed onto
3433 another serial port. The monitor is accessed with key sequence of
3434 @key{Control-a} and then pressing @key{c}.
3435 @var{dev_string} should be any one of the serial devices specified
3436 above. An example to multiplex the monitor onto a telnet server
3437 listening on port 4444 would be:
3439 @item -serial mon:telnet::4444,server,nowait
3441 When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3442 QEMU any more but will be passed to the guest instead.
3445 Braille device. This will use BrlAPI to display the braille output on a real
3449 Three button serial mouse. Configure the guest to use Microsoft protocol.
3453 DEF("parallel
", HAS_ARG, QEMU_OPTION_parallel, \
3454 "-parallel dev redirect the parallel port to char device
'dev'\n",
3457 @item -parallel @var{dev}
3459 Redirect the virtual parallel port to host device @var{dev} (same
3460 devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3461 be used to use hardware devices connected on the corresponding host
3464 This option can be used several times to simulate up to 3 parallel
3467 Use @code{-parallel none} to disable all parallel ports.
3470 DEF("monitor
", HAS_ARG, QEMU_OPTION_monitor, \
3471 "-monitor dev redirect the monitor to char device
'dev'\n",
3474 @item -monitor @var{dev}
3476 Redirect the monitor to host device @var{dev} (same devices as the
3478 The default device is @code{vc} in graphical mode and @code{stdio} in
3480 Use @code{-monitor none} to disable the default monitor.
3482 DEF("qmp
", HAS_ARG, QEMU_OPTION_qmp, \
3483 "-qmp dev like
-monitor but opens
in 'control' mode
\n",
3486 @item -qmp @var{dev}
3488 Like -monitor but opens in 'control' mode.
3490 DEF("qmp
-pretty
", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3491 "-qmp
-pretty dev like
-qmp but uses pretty JSON formatting
\n",
3494 @item -qmp-pretty @var{dev}
3496 Like -qmp but uses pretty JSON formatting.
3499 DEF("mon
", HAS_ARG, QEMU_OPTION_mon, \
3500 "-mon
[chardev
=]name
[,mode
=readline|control
][,pretty
[=on|off
]]\n", QEMU_ARCH_ALL)
3502 @item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]
3504 Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing
3505 easing human reading and debugging.
3508 DEF("debugcon
", HAS_ARG, QEMU_OPTION_debugcon, \
3509 "-debugcon dev redirect the debug console to char device
'dev'\n",
3512 @item -debugcon @var{dev}
3514 Redirect the debug console to host device @var{dev} (same devices as the
3515 serial port). The debug console is an I/O port which is typically port
3516 0xe9; writing to that I/O port sends output to this device.
3517 The default device is @code{vc} in graphical mode and @code{stdio} in
3521 DEF("pidfile
", HAS_ARG, QEMU_OPTION_pidfile, \
3522 "-pidfile file write PID to
'file'\n", QEMU_ARCH_ALL)
3524 @item -pidfile @var{file}
3526 Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3530 DEF("singlestep
", 0, QEMU_OPTION_singlestep, \
3531 "-singlestep always run
in singlestep mode
\n", QEMU_ARCH_ALL)
3535 Run the emulation in single step mode.
3538 DEF("preconfig
", 0, QEMU_OPTION_preconfig, \
3539 "--preconfig pause QEMU before machine is
initialized (experimental
)\n",
3544 Pause QEMU for interactive configuration before the machine is created,
3545 which allows querying and configuring properties that will affect
3546 machine initialization. Use QMP command 'x-exit-preconfig' to exit
3547 the preconfig state and move to the next state (i.e. run guest if -S
3548 isn't used or pause the second time if -S is used). This option is
3552 DEF("S
", 0, QEMU_OPTION_S, \
3553 "-S freeze CPU at
startup (use
'c' to start execution
)\n",
3558 Do not start CPU at startup (you must type 'c' in the monitor).
3561 DEF("realtime
", HAS_ARG, QEMU_OPTION_realtime,
3562 "-realtime
[mlock
=on|off
]\n"
3563 " run qemu with realtime features
\n"
3564 " mlock
=on|off controls mlock
support (default: on
)\n",
3567 @item -realtime mlock=on|off
3569 Run qemu with realtime features.
3570 mlocking qemu and guest memory can be enabled via @option{mlock=on}
3571 (enabled by default).
3574 DEF("overcommit
", HAS_ARG, QEMU_OPTION_overcommit,
3575 "-overcommit
[mem
-lock
=on|off
][cpu
-pm
=on|off
]\n"
3576 " run qemu with overcommit hints
\n"
3577 " mem
-lock
=on|off controls memory lock
support (default: off
)\n"
3578 " cpu
-pm
=on|off controls cpu power
management (default: off
)\n",
3581 @item -overcommit mem-lock=on|off
3582 @item -overcommit cpu-pm=on|off
3584 Run qemu with hints about host resource overcommit. The default is
3585 to assume that host overcommits all resources.
3587 Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3588 by default). This works when host memory is not overcommitted and reduces the
3589 worst-case latency for guest. This is equivalent to @option{realtime}.
3591 Guest ability to manage power state of host cpus (increasing latency for other
3592 processes on the same host cpu, but decreasing latency for guest) can be
3593 enabled via @option{cpu-pm=on} (disabled by default). This works best when
3594 host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3595 utilization will be incorrect, not taking into account guest idle time.
3598 DEF("gdb
", HAS_ARG, QEMU_OPTION_gdb, \
3599 "-gdb dev wait
for gdb connection on
'dev'\n", QEMU_ARCH_ALL)
3601 @item -gdb @var{dev}
3603 Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3604 connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3605 stdio are reasonable use case. The latter is allowing to start QEMU from
3606 within gdb and establish the connection via a pipe:
3608 (gdb) target remote | exec @value{qemu_system} -gdb stdio ...
3612 DEF("s
", 0, QEMU_OPTION_s, \
3613 "-s shorthand
for -gdb tcp
::" DEFAULT_GDBSTUB_PORT "\n",
3618 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3619 (@pxref{gdb_usage}).
3622 DEF("d
", HAS_ARG, QEMU_OPTION_d, \
3623 "-d item1
,... enable logging of specified
items (use
'-d help' for a list of log items
)\n",
3626 @item -d @var{item1}[,...]
3628 Enable logging of specified items. Use '-d help' for a list of log items.
3631 DEF("D
", HAS_ARG, QEMU_OPTION_D, \
3632 "-D logfile output log to
logfile (default stderr
)\n",
3635 @item -D @var{logfile}
3637 Output log in @var{logfile} instead of to stderr
3640 DEF("dfilter
", HAS_ARG, QEMU_OPTION_DFILTER, \
3641 "-dfilter range
,.. filter debug output to range of
addresses (useful
for -d cpu
,exec
,etc
..)\n",
3644 @item -dfilter @var{range1}[,...]
3646 Filter debug output to that relevant to a range of target addresses. The filter
3647 spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3648 @var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3649 addresses and sizes required. For example:
3651 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3653 Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3654 the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3655 block starting at 0xffffffc00005f000.
3658 DEF("seed
", HAS_ARG, QEMU_OPTION_seed, \
3659 "-seed number seed the pseudo
-random number generator
\n",
3662 @item -seed @var{number}
3664 Force the guest to use a deterministic pseudo-random number generator, seeded
3665 with @var{number}. This does not affect crypto routines within the host.
3668 DEF("L
", HAS_ARG, QEMU_OPTION_L, \
3669 "-L path set the directory
for the BIOS
, VGA BIOS and keymaps
\n",
3674 Set the directory for the BIOS, VGA BIOS and keymaps.
3676 To list all the data directories, use @code{-L help}.
3679 DEF("bios
", HAS_ARG, QEMU_OPTION_bios, \
3680 "-bios file set the filename
for the BIOS
\n", QEMU_ARCH_ALL)
3682 @item -bios @var{file}
3684 Set the filename for the BIOS.
3687 DEF("enable
-kvm
", 0, QEMU_OPTION_enable_kvm, \
3688 "-enable
-kvm enable KVM full virtualization support
\n", QEMU_ARCH_ALL)
3692 Enable KVM full virtualization support. This option is only available
3693 if KVM support is enabled when compiling.
3696 DEF("xen
-domid
", HAS_ARG, QEMU_OPTION_xen_domid,
3697 "-xen
-domid id specify xen guest domain id
\n", QEMU_ARCH_ALL)
3698 DEF("xen
-attach
", 0, QEMU_OPTION_xen_attach,
3699 "-xen
-attach attach to existing xen domain
\n"
3700 " libxl will use
this when starting QEMU
\n",
3702 DEF("xen
-domid
-restrict
", 0, QEMU_OPTION_xen_domid_restrict,
3703 "-xen
-domid
-restrict restrict set of available xen operations
\n"
3704 " to specified domain id
. (Does not affect
\n"
3705 " xenpv machine type
).\n",
3708 @item -xen-domid @var{id}
3710 Specify xen guest domain @var{id} (XEN only).
3713 Attach to existing xen domain.
3714 libxl will use this when starting QEMU (XEN only).
3715 @findex -xen-domid-restrict
3716 Restrict set of available xen operations to specified domain id (XEN only).
3719 DEF("no
-reboot
", 0, QEMU_OPTION_no_reboot, \
3720 "-no
-reboot exit instead of rebooting
\n", QEMU_ARCH_ALL)
3724 Exit instead of rebooting.
3727 DEF("no
-shutdown
", 0, QEMU_OPTION_no_shutdown, \
3728 "-no
-shutdown stop before shutdown
\n", QEMU_ARCH_ALL)
3731 @findex -no-shutdown
3732 Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3733 This allows for instance switching to monitor to commit changes to the
3737 DEF("loadvm
", HAS_ARG, QEMU_OPTION_loadvm, \
3738 "-loadvm
[tag|id
]\n" \
3739 " start right away with a saved
state (loadvm
in monitor
)\n",
3742 @item -loadvm @var{file}
3744 Start right away with a saved state (@code{loadvm} in monitor)
3748 DEF("daemonize
", 0, QEMU_OPTION_daemonize, \
3749 "-daemonize daemonize QEMU after initializing
\n", QEMU_ARCH_ALL)
3754 Daemonize the QEMU process after initialization. QEMU will not detach from
3755 standard IO until it is ready to receive connections on any of its devices.
3756 This option is a useful way for external programs to launch QEMU without having
3757 to cope with initialization race conditions.
3760 DEF("option
-rom
", HAS_ARG, QEMU_OPTION_option_rom, \
3761 "-option
-rom rom load a file
, rom
, into the option ROM space
\n",
3764 @item -option-rom @var{file}
3766 Load the contents of @var{file} as an option ROM.
3767 This option is useful to load things like EtherBoot.
3770 DEF("rtc
", HAS_ARG, QEMU_OPTION_rtc, \
3771 "-rtc
[base
=utc|localtime|
<datetime
>][,clock
=host|rt|vm
][,driftfix
=none|slew
]\n" \
3772 " set the RTC base and clock
, enable drift fix
for clock
ticks (x86 only
)\n",
3777 @item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew]
3779 Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3780 UTC or local time, respectively. @code{localtime} is required for correct date in
3781 MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the
3782 format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3784 By default the RTC is driven by the host system time. This allows using of the
3785 RTC as accurate reference clock inside the guest, specifically if the host
3786 time is smoothly following an accurate external reference clock, e.g. via NTP.
3787 If you want to isolate the guest time from the host, you can set @option{clock}
3788 to @code{rt} instead, which provides a host monotonic clock if host support it.
3789 To even prevent the RTC from progressing during suspension, you can set @option{clock}
3790 to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in
3791 icount mode in order to preserve determinism; however, note that in icount mode
3792 the speed of the virtual clock is variable and can in general differ from the
3795 Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3796 specifically with Windows' ACPI HAL. This option will try to figure out how
3797 many timer interrupts were not processed by the Windows guest and will
3801 DEF("icount
", HAS_ARG, QEMU_OPTION_icount, \
3802 "-icount
[shift
=N|auto
][,align
=on|off
][,sleep
=on|off
,rr
=record|replay
,rrfile
=<filename
>,rrsnapshot
=<snapshot
>]\n" \
3803 " enable virtual instruction counter with
2^N clock ticks per
\n" \
3804 " instruction
, enable aligning the host and virtual clocks
\n" \
3805 " or disable real time cpu sleeping
\n", QEMU_ARCH_ALL)
3807 @item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3809 Enable virtual instruction counter. The virtual cpu will execute one
3810 instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified
3811 then the virtual cpu speed will be automatically adjusted to keep virtual
3812 time within a few seconds of real time.
3814 When the virtual cpu is sleeping, the virtual time will advance at default
3815 speed unless @option{sleep=on|off} is specified.
3816 With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3817 instantly whenever the virtual cpu goes to sleep mode and will not advance
3818 if no timer is enabled. This behavior give deterministic execution times from
3819 the guest point of view.
3821 Note that while this option can give deterministic behavior, it does not
3822 provide cycle accurate emulation. Modern CPUs contain superscalar out of
3823 order cores with complex cache hierarchies. The number of instructions
3824 executed often has little or no correlation with actual performance.
3826 @option{align=on} will activate the delay algorithm which will try
3827 to synchronise the host clock and the virtual clock. The goal is to
3828 have a guest running at the real frequency imposed by the shift option.
3829 Whenever the guest clock is behind the host clock and if
3830 @option{align=on} is specified then we print a message to the user
3831 to inform about the delay.
3832 Currently this option does not work when @option{shift} is @code{auto}.
3833 Note: The sync algorithm will work for those shift values for which
3834 the guest clock runs ahead of the host clock. Typically this happens
3835 when the shift value is high (how high depends on the host machine).
3837 When @option{rr} option is specified deterministic record/replay is enabled.
3838 Replay log is written into @var{filename} file in record mode and
3839 read from this file in replay mode.
3841 Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3842 at the start of execution recording. In replay mode this option is used
3843 to load the initial VM state.
3846 DEF("watchdog
", HAS_ARG, QEMU_OPTION_watchdog, \
3847 "-watchdog model
\n" \
3848 " enable virtual hardware watchdog
[default=none
]\n",
3851 @item -watchdog @var{model}
3853 Create a virtual hardware watchdog device. Once enabled (by a guest
3854 action), the watchdog must be periodically polled by an agent inside
3855 the guest or else the guest will be restarted. Choose a model for
3856 which your guest has drivers.
3858 The @var{model} is the model of hardware watchdog to emulate. Use
3859 @code{-watchdog help} to list available hardware models. Only one
3860 watchdog can be enabled for a guest.
3862 The following models may be available:
3865 iBASE 700 is a very simple ISA watchdog with a single timer.
3867 Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3868 dual-timer watchdog.
3870 A virtual watchdog for s390x backed by the diagnose 288 hypercall
3871 (currently KVM only).
3875 DEF("watchdog
-action
", HAS_ARG, QEMU_OPTION_watchdog_action, \
3876 "-watchdog
-action reset|shutdown|poweroff|inject
-nmi|pause|debug|none
\n" \
3877 " action when watchdog fires
[default=reset
]\n",
3880 @item -watchdog-action @var{action}
3881 @findex -watchdog-action
3883 The @var{action} controls what QEMU will do when the watchdog timer
3886 @code{reset} (forcefully reset the guest).
3887 Other possible actions are:
3888 @code{shutdown} (attempt to gracefully shutdown the guest),
3889 @code{poweroff} (forcefully poweroff the guest),
3890 @code{inject-nmi} (inject a NMI into the guest),
3891 @code{pause} (pause the guest),
3892 @code{debug} (print a debug message and continue), or
3893 @code{none} (do nothing).
3895 Note that the @code{shutdown} action requires that the guest responds
3896 to ACPI signals, which it may not be able to do in the sort of
3897 situations where the watchdog would have expired, and thus
3898 @code{-watchdog-action shutdown} is not recommended for production use.
3903 @item -watchdog i6300esb -watchdog-action pause
3904 @itemx -watchdog ib700
3908 DEF("echr
", HAS_ARG, QEMU_OPTION_echr, \
3909 "-echr chr set terminal escape character instead of ctrl
-a
\n",
3913 @item -echr @var{numeric_ascii_value}
3915 Change the escape character used for switching to the monitor when using
3916 monitor and serial sharing. The default is @code{0x01} when using the
3917 @code{-nographic} option. @code{0x01} is equal to pressing
3918 @code{Control-a}. You can select a different character from the ascii
3919 control keys where 1 through 26 map to Control-a through Control-z. For
3920 instance you could use the either of the following to change the escape
3921 character to Control-t.
3928 DEF("show
-cursor
", 0, QEMU_OPTION_show_cursor, \
3929 "-show
-cursor show cursor
\n", QEMU_ARCH_ALL)
3932 @findex -show-cursor
3936 DEF("tb
-size
", HAS_ARG, QEMU_OPTION_tb_size, \
3937 "-tb
-size n set TB size
\n", QEMU_ARCH_ALL)
3939 @item -tb-size @var{n}
3944 DEF("incoming
", HAS_ARG, QEMU_OPTION_incoming, \
3945 "-incoming tcp
:[host
]:port
[,to
=maxport
][,ipv4
][,ipv6
]\n" \
3946 "-incoming rdma
:host
:port
[,ipv4
][,ipv6
]\n" \
3947 "-incoming unix
:socketpath
\n" \
3948 " prepare
for incoming migration
, listen on
\n" \
3949 " specified protocol and socket address
\n" \
3950 "-incoming fd
:fd
\n" \
3951 "-incoming exec
:cmdline
\n" \
3952 " accept incoming migration on given file descriptor
\n" \
3953 " or from given external command
\n" \
3954 "-incoming defer
\n" \
3955 " wait
for the URI to be specified via migrate_incoming
\n",
3958 @item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
3959 @itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
3961 Prepare for incoming migration, listen on a given tcp port.
3963 @item -incoming unix:@var{socketpath}
3964 Prepare for incoming migration, listen on a given unix socket.
3966 @item -incoming fd:@var{fd}
3967 Accept incoming migration from a given filedescriptor.
3969 @item -incoming exec:@var{cmdline}
3970 Accept incoming migration as an output from specified external command.
3972 @item -incoming defer
3973 Wait for the URI to be specified via migrate_incoming. The monitor can
3974 be used to change settings (such as migration parameters) prior to issuing
3975 the migrate_incoming to allow the migration to begin.
3978 DEF("only
-migratable
", 0, QEMU_OPTION_only_migratable, \
3979 "-only
-migratable allow only migratable devices
\n", QEMU_ARCH_ALL)
3981 @item -only-migratable
3982 @findex -only-migratable
3983 Only allow migratable devices. Devices will not be allowed to enter an
3987 DEF("nodefaults
", 0, QEMU_OPTION_nodefaults, \
3988 "-nodefaults don
't create default devices\n", QEMU_ARCH_ALL)
3992 Don't create
default devices
. Normally
, QEMU sets the
default devices like serial
3993 port
, parallel port
, virtual console
, monitor device
, VGA adapter
, floppy and
3994 CD
-ROM drive and others
. The @code
{-nodefaults
} option will disable all those
3999 DEF("chroot", HAS_ARG
, QEMU_OPTION_chroot
, \
4000 "-chroot dir chroot to dir just before starting the VM\n",
4004 @item
-chroot @
var{dir
}
4006 Immediately before starting guest execution
, chroot to the specified
4007 directory
. Especially useful
in combination with
-runas
.
4011 DEF("runas", HAS_ARG
, QEMU_OPTION_runas
, \
4012 "-runas user change to user id user just before starting the VM\n" \
4013 " user can be numeric uid:gid instead\n",
4017 @item
-runas @
var{user
}
4019 Immediately before starting guest execution
, drop root privileges
, switching
4020 to the specified user
.
4023 DEF("prom-env", HAS_ARG
, QEMU_OPTION_prom_env
,
4024 "-prom-env variable=value\n"
4025 " set OpenBIOS nvram variables\n",
4026 QEMU_ARCH_PPC | QEMU_ARCH_SPARC
)
4028 @item
-prom
-env @
var{variable
}=@
var{value
}
4030 Set OpenBIOS nvram @
var{variable
} to given @
var{value
} (PPC
, SPARC only
).
4032 DEF("semihosting", 0, QEMU_OPTION_semihosting
,
4033 "-semihosting semihosting mode\n",
4034 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4035 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2
)
4038 @findex
-semihosting
4039 Enable semihosting
mode (ARM
, M68K
, Xtensa
, MIPS
, Nios II only
).
4041 DEF("semihosting-config", HAS_ARG
, QEMU_OPTION_semihosting_config
,
4042 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
4043 " semihosting configuration\n",
4044 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4045 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2
)
4047 @item
-semihosting
-config
[enable
=on|off
][,target
=native|gdb|auto
][,chardev
=id
][,arg
=str
[,...]]
4048 @findex
-semihosting
-config
4049 Enable and configure
semihosting (ARM
, M68K
, Xtensa
, MIPS
, Nios II only
).
4051 @item target
=@code
{native|gdb|auto
}
4052 Defines where the semihosting calls will be addressed
, to
QEMU (@code
{native
})
4053 or to
GDB (@code
{gdb
}). The
default is @code
{auto
}, which means @code
{gdb
}
4054 during debug sessions and @code
{native
} otherwise
.
4055 @item chardev
=@
var{str1
}
4056 Send the output to a chardev backend output
for native or auto output when not
in gdb
4057 @item arg
=@
var{str1
},arg
=@
var{str2
},...
4058 Allows the user to pass input arguments
, and can be used multiple times to build
4059 up a list
. The old
-style @code
{-kernel
}/@code
{-append
} method of passing a
4060 command line is still supported
for backward compatibility
. If both the
4061 @code
{--semihosting
-config arg
} and the @code
{-kernel
}/@code
{-append
} are
4062 specified
, the former is passed to semihosting as it always takes precedence
.
4065 DEF("old-param", 0, QEMU_OPTION_old_param
,
4066 "-old-param old param mode\n", QEMU_ARCH_ARM
)
4069 @findex
-old
-param (ARM
)
4070 Old param
mode (ARM only
).
4073 DEF("sandbox", HAS_ARG
, QEMU_OPTION_sandbox
, \
4074 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4075 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4076 " Enable seccomp mode 2 system call filter (default 'off').\n" \
4077 " use 'obsolete' to allow obsolete system calls that are provided\n" \
4078 " by the kernel, but typically no longer used by modern\n" \
4079 " C library implementations.\n" \
4080 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
4081 " its privileges by blacklisting all set*uid|gid system calls.\n" \
4082 " The value 'children' will deny set*uid|gid system calls for\n" \
4083 " main QEMU process but will allow forks and execves to run unprivileged\n" \
4084 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4085 " blacklisting *fork and execve\n" \
4086 " use 'resourcecontrol' to disable process affinity and schedular priority\n",
4089 @item
-sandbox @
var{arg
}[,obsolete
=@
var{string
}][,elevateprivileges
=@
var{string
}][,spawn
=@
var{string
}][,resourcecontrol
=@
var{string
}]
4091 Enable Seccomp mode
2 system call filter
. 'on' will enable syscall filtering and
'off' will
4092 disable it
. The
default is
'off'.
4094 @item obsolete
=@
var{string
}
4095 Enable Obsolete system calls
4096 @item elevateprivileges
=@
var{string
}
4097 Disable set
*uid|gid system calls
4098 @item spawn
=@
var{string
}
4099 Disable
*fork and execve
4100 @item resourcecontrol
=@
var{string
}
4101 Disable process affinity and schedular priority
4105 DEF("readconfig", HAS_ARG
, QEMU_OPTION_readconfig
,
4106 "-readconfig <file>\n", QEMU_ARCH_ALL
)
4108 @item
-readconfig @
var{file
}
4110 Read device configuration from @
var{file
}. This approach is useful when you want to spawn
4111 QEMU process with many command line options but you don
't want to exceed the command line
4114 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
4115 "-writeconfig <file>\n"
4116 " read/write config file\n", QEMU_ARCH_ALL)
4118 @item -writeconfig @var{file}
4119 @findex -writeconfig
4120 Write device configuration to @var{file}. The @var{file} can be either filename to save
4121 command line and device configuration into file or dash @code{-}) character to print the
4122 output to stdout. This can be later used as input file for @code{-readconfig} option.
4125 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4127 " do not load default user-provided config files at startup\n",
4130 @item -no-user-config
4131 @findex -no-user-config
4132 The @code{-no-user-config} option makes QEMU not load any of the user-provided
4133 config files on @var{sysconfdir}.
4136 DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4137 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4138 " specify tracing options\n",
4141 HXCOMM This line is not accurate, as some sub-options are backend-specific but
4142 HXCOMM HX does not support conditional compilation of text.
4143 @item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
4145 @include qemu-option-trace.texi
4149 DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4150 DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4153 DEF("enable-fips", 0, QEMU_OPTION_enablefips,
4154 "-enable-fips enable FIPS 140-2 compliance\n",
4159 @findex -enable-fips
4160 Enable FIPS 140-2 compliance mode.
4163 HXCOMM Deprecated by -machine accel=tcg property
4164 DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
4166 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4167 "-msg timestamp[=on|off]\n"
4168 " change the format of messages\n"
4169 " on|off controls leading timestamps (default:on)\n",
4172 @item -msg timestamp[=on|off]
4174 prepend a timestamp to each log message.(default:on)
4177 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4178 "-dump-vmstate <file>\n"
4179 " Output vmstate information in JSON format to file.\n"
4180 " Use the scripts/vmstate-static-checker.py file to\n"
4181 " check for possible regressions in migration code\n"
4182 " by comparing two such vmstate dumps.\n",
4185 @item -dump-vmstate @var{file}
4186 @findex -dump-vmstate
4187 Dump json-encoded vmstate information for current machine type to file
4191 DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4192 "-enable-sync-profile\n"
4193 " enable synchronization profiling\n",
4196 @item -enable-sync-profile
4197 @findex -enable-sync-profile
4198 Enable synchronization profiling.
4206 DEFHEADING(Generic object creation:)
4211 DEF("object", HAS_ARG, QEMU_OPTION_object,
4212 "-object TYPENAME[,PROP1=VALUE1,...]\n"
4213 " create a new object of type TYPENAME setting properties\n"
4214 " in the order they are specified. Note that the 'id
'\n"
4215 " property must be set. These objects are placed in the\n"
4216 " '/objects
' path.\n",
4219 @item -object @var{typename}[,@var{prop1}=@var{value1},...]
4221 Create a new object of type @var{typename} setting properties
4222 in the order they are specified. Note that the 'id
'
4223 property must be set. These objects are placed in the
4228 @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}
4230 Creates a memory file backend object, which can be used to back
4231 the guest RAM with huge pages.
4233 The @option{id} parameter is a unique ID that will be used to reference this
4234 memory region when configuring the @option{-numa} argument.
4236 The @option{size} option provides the size of the memory region, and accepts
4237 common suffixes, eg @option{500M}.
4239 The @option{mem-path} provides the path to either a shared memory or huge page
4242 The @option{share} boolean option determines whether the memory
4243 region is marked as private to QEMU, or shared. The latter allows
4244 a co-operating external process to access the QEMU memory region.
4246 The @option{share} is also required for pvrdma devices due to
4247 limitations in the RDMA API provided by Linux.
4249 Setting share=on might affect the ability to configure NUMA
4250 bindings for the memory backend under some circumstances, see
4251 Documentation/vm/numa_memory_policy.txt on the Linux kernel
4252 source tree for additional details.
4254 Setting the @option{discard-data} boolean option to @var{on}
4255 indicates that file contents can be destroyed when QEMU exits,
4256 to avoid unnecessarily flushing data to the backing file. Note
4257 that @option{discard-data} is only an optimization, and QEMU
4258 might not discard file contents if it aborts unexpectedly or is
4259 terminated using SIGKILL.
4261 The @option{merge} boolean option enables memory merge, also known as
4262 MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
4263 memory deduplication.
4265 Setting the @option{dump} boolean option to @var{off} excludes the memory from
4266 core dumps. This feature is also known as MADV_DONTDUMP.
4268 The @option{prealloc} boolean option enables memory preallocation.
4270 The @option{host-nodes} option binds the memory range to a list of NUMA host
4273 The @option{policy} option sets the NUMA policy to one of the following values:
4279 @item @var{preferred}
4280 prefer the given host node list for allocation
4283 restrict memory allocation to the given host node list
4285 @item @var{interleave}
4286 interleave memory allocations across the given host node list
4289 The @option{align} option specifies the base address alignment when
4290 QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4291 @option{2M}. Some backend store specified by @option{mem-path}
4292 requires an alignment different than the default one used by QEMU, eg
4293 the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4294 such cases, users can specify the required alignment via this option.
4296 The @option{pmem} option specifies whether the backing file specified
4297 by @option{mem-path} is in host persistent memory that can be accessed
4298 using the SNIA NVM programming model (e.g. Intel NVDIMM).
4299 If @option{pmem} is set to 'on
', QEMU will take necessary operations to
4300 guarantee the persistence of its own writes to @option{mem-path}
4301 (e.g. in vNVDIMM label emulation and live migration).
4302 Also, we will map the backend-file with MAP_SYNC flag, which ensures the
4303 file metadata is in sync for @option{mem-path} in case of host crash
4304 or a power failure. MAP_SYNC requires support from both the host kernel
4305 (since Linux kernel 4.15) and the filesystem of @option{mem-path} mounted
4308 @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}
4310 Creates a memory backend object, which can be used to back the guest RAM.
4311 Memory backend objects offer more control than the @option{-m} option that is
4312 traditionally used to define guest RAM. Please refer to
4313 @option{memory-backend-file} for a description of the options.
4315 @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}
4317 Creates an anonymous memory file backend object, which allows QEMU to
4318 share the memory with an external process (e.g. when using
4319 vhost-user). The memory is allocated with memfd and optional
4320 sealing. (Linux only)
4322 The @option{seal} option creates a sealed-file, that will block
4323 further resizing the memory ('on
' by default).
4325 The @option{hugetlb} option specify the file to be created resides in
4326 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction with
4327 the @option{hugetlb} option, the @option{hugetlbsize} option specify
4328 the hugetlb page size on systems that support multiple hugetlb page
4329 sizes (it must be a power of 2 value supported by the system).
4331 In some versions of Linux, the @option{hugetlb} option is incompatible
4332 with the @option{seal} option (requires at least Linux 4.16).
4334 Please refer to @option{memory-backend-file} for a description of the
4337 The @option{share} boolean option is @var{on} by default with memfd.
4339 @item -object rng-builtin,id=@var{id}
4341 Creates a random number generator backend which obtains entropy from
4342 QEMU builtin functions. The @option{id} parameter is a unique ID that
4343 will be used to reference this entropy backend from the @option{virtio-rng}
4344 device. By default, the @option{virtio-rng} device uses this RNG backend.
4346 @item -object rng-random,id=@var{id},filename=@var{/dev/random}
4348 Creates a random number generator backend which obtains entropy from
4349 a device on the host. The @option{id} parameter is a unique ID that
4350 will be used to reference this entropy backend from the @option{virtio-rng}
4351 device. The @option{filename} parameter specifies which file to obtain
4352 entropy from and if omitted defaults to @option{/dev/urandom}.
4354 @item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4356 Creates a random number generator backend which obtains entropy from
4357 an external daemon running on the host. The @option{id} parameter is
4358 a unique ID that will be used to reference this entropy backend from
4359 the @option{virtio-rng} device. The @option{chardev} parameter is
4360 the unique ID of a character device backend that provides the connection
4363 @item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4365 Creates a TLS anonymous credentials object, which can be used to provide
4366 TLS support on network backends. The @option{id} parameter is a unique
4367 ID which network backends will use to access the credentials. The
4368 @option{endpoint} is either @option{server} or @option{client} depending
4369 on whether the QEMU network backend that uses the credentials will be
4370 acting as a client or as a server. If @option{verify-peer} is enabled
4371 (the default) then once the handshake is completed, the peer credentials
4372 will be verified, though this is a no-op for anonymous credentials.
4374 The @var{dir} parameter tells QEMU where to find the credential
4375 files. For server endpoints, this directory may contain a file
4376 @var{dh-params.pem} providing diffie-hellman parameters to use
4377 for the TLS server. If the file is missing, QEMU will generate
4378 a set of DH parameters at startup. This is a computationally
4379 expensive operation that consumes random pool entropy, so it is
4380 recommended that a persistent set of parameters be generated
4383 @item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4385 Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4386 TLS support on network backends. The @option{id} parameter is a unique
4387 ID which network backends will use to access the credentials. The
4388 @option{endpoint} is either @option{server} or @option{client} depending
4389 on whether the QEMU network backend that uses the credentials will be
4390 acting as a client or as a server. For clients only, @option{username}
4391 is the username which will be sent to the server. If omitted
4392 it defaults to ``qemu''.
4394 The @var{dir} parameter tells QEMU where to find the keys file.
4395 It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4396 pairs. This file can most easily be created using the GnuTLS
4397 @code{psktool} program.
4399 For server endpoints, @var{dir} may also contain a file
4400 @var{dh-params.pem} providing diffie-hellman parameters to use
4401 for the TLS server. If the file is missing, QEMU will generate
4402 a set of DH parameters at startup. This is a computationally
4403 expensive operation that consumes random pool entropy, so it is
4404 recommended that a persistent set of parameters be generated
4407 @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}
4409 Creates a TLS anonymous credentials object, which can be used to provide
4410 TLS support on network backends. The @option{id} parameter is a unique
4411 ID which network backends will use to access the credentials. The
4412 @option{endpoint} is either @option{server} or @option{client} depending
4413 on whether the QEMU network backend that uses the credentials will be
4414 acting as a client or as a server. If @option{verify-peer} is enabled
4415 (the default) then once the handshake is completed, the peer credentials
4416 will be verified. With x509 certificates, this implies that the clients
4417 must be provided with valid client certificates too.
4419 The @var{dir} parameter tells QEMU where to find the credential
4420 files. For server endpoints, this directory may contain a file
4421 @var{dh-params.pem} providing diffie-hellman parameters to use
4422 for the TLS server. If the file is missing, QEMU will generate
4423 a set of DH parameters at startup. This is a computationally
4424 expensive operation that consumes random pool entropy, so it is
4425 recommended that a persistent set of parameters be generated
4428 For x509 certificate credentials the directory will contain further files
4429 providing the x509 certificates. The certificates must be stored
4430 in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4431 @var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4432 @var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4434 For the @var{server-key.pem} and @var{client-key.pem} files which
4435 contain sensitive private keys, it is possible to use an encrypted
4436 version by providing the @var{passwordid} parameter. This provides
4437 the ID of a previously created @code{secret} object containing the
4438 password for decryption.
4440 The @var{priority} parameter allows to override the global default
4441 priority used by gnutls. This can be useful if the system administrator
4442 needs to use a weaker set of crypto priorities for QEMU without
4443 potentially forcing the weakness onto all applications. Or conversely
4444 if one wants wants a stronger default for QEMU than for all other
4445 applications, they can do this through this parameter. Its format is
4446 a gnutls priority string as described at
4447 @url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4449 @item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4451 Interval @var{t} can't be
0, this filter batches the packet delivery
: all
4452 packets arriving
in a given interval on netdev @
var{netdevid
} are delayed
4453 until the end of the interval
. Interval is
in microseconds
.
4454 @option
{status
} is optional that indicate whether the netfilter is
4455 on (enabled
) or
off (disabled
), the
default status
for netfilter will be
'on'.
4457 queue @
var{all|rx|tx
} is an option that can be applied to any netfilter
.
4459 @option
{all
}: the filter is attached both to the receive and the transmit
4460 queue of the
netdev (default).
4462 @option
{rx
}: the filter is attached to the receive queue of the netdev
,
4463 where it will receive packets sent to the netdev
.
4465 @option
{tx
}: the filter is attached to the transmit queue of the netdev
,
4466 where it will receive packets sent by the netdev
.
4468 @item
-object filter
-mirror
,id
=@
var{id
},netdev
=@
var{netdevid
},outdev
=@
var{chardevid
},queue
=@
var{all|rx|tx
}[,vnet_hdr_support
]
4470 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
.
4472 @item
-object filter
-redirector
,id
=@
var{id
},netdev
=@
var{netdevid
},indev
=@
var{chardevid
},outdev
=@
var{chardevid
},queue
=@
var{all|rx|tx
}[,vnet_hdr_support
]
4474 filter
-redirector on netdev @
var{netdevid
},redirect filter
's net packet to chardev
4475 @var{chardevid},and redirect indev's packet to filter
.if it has the vnet_hdr_support flag
,
4476 filter
-redirector will redirect packet with vnet_hdr_len
.
4477 Create a filter
-redirector we need to differ outdev id from indev id
, id can not
4478 be the same
. we can just use indev or outdev
, but at least one of indev or outdev
4479 need to be specified
.
4481 @item
-object filter
-rewriter
,id
=@
var{id
},netdev
=@
var{netdevid
},queue
=@
var{all|rx|tx
},[vnet_hdr_support
]
4483 Filter
-rewriter is a part of COLO project
.It will rewrite tcp packet to
4484 secondary from primary to keep secondary tcp connection
,and rewrite
4485 tcp packet to primary from secondary make tcp packet can be handled by
4486 client
.if it has the vnet_hdr_support flag
, we can parse packet with vnet header
.
4490 -object filter
-redirector
,id
=f1
,netdev
=hn0
,queue
=tx
,indev
=red0
4491 -object filter
-redirector
,id
=f2
,netdev
=hn0
,queue
=rx
,outdev
=red1
4492 -object filter
-rewriter
,id
=rew0
,netdev
=hn0
,queue
=all
4494 @item
-object filter
-dump
,id
=@
var{id
},netdev
=@
var{dev
}[,file
=@
var{filename
}][,maxlen
=@
var{len
}]
4496 Dump the network traffic on netdev @
var{dev
} to the file specified by
4497 @
var{filename
}. At most @
var{len
} bytes (64k by
default) per packet are stored
.
4498 The file format is libpcap
, so it can be analyzed with tools such as tcpdump
4501 @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
}]
4503 Colo
-compare gets packet from primary_in@
var{chardevid
} and secondary_in@
var{chardevid
}, than compare primary packet with
4504 secondary packet
. If the packets are same
, we will output primary
4505 packet to outdev@
var{chardevid
}, else we will notify colo
-frame
4506 do checkpoint and send primary packet to outdev@
var{chardevid
}.
4507 In order to improve efficiency
, we need to put the task of comparison
4508 in another thread
. If it has the vnet_hdr_support flag
, colo compare
4509 will send
/recv packet with vnet_hdr_len
.
4510 If you want to use Xen COLO
, will need the notify_dev to notify Xen
4511 colo
-frame to
do checkpoint
.
4513 we must use it with the help of filter
-mirror and filter
-redirector
.
4520 -netdev tap
,id
=hn0
,vhost
=off
,script
=/etc
/qemu
-ifup
,downscript
=/etc
/qemu
-ifdown
4521 -device e1000
,id
=e0
,netdev
=hn0
,mac
=52:a4
:00:12:78:66
4522 -chardev socket
,id
=mirror0
,host
=3.3.3.3,port
=9003,server
,nowait
4523 -chardev socket
,id
=compare1
,host
=3.3.3.3,port
=9004,server
,nowait
4524 -chardev socket
,id
=compare0
,host
=3.3.3.3,port
=9001,server
,nowait
4525 -chardev socket
,id
=compare0
-0,host
=3.3.3.3,port
=9001
4526 -chardev socket
,id
=compare_out
,host
=3.3.3.3,port
=9005,server
,nowait
4527 -chardev socket
,id
=compare_out0
,host
=3.3.3.3,port
=9005
4528 -object iothread
,id
=iothread1
4529 -object filter
-mirror
,id
=m0
,netdev
=hn0
,queue
=tx
,outdev
=mirror0
4530 -object filter
-redirector
,netdev
=hn0
,id
=redire0
,queue
=rx
,indev
=compare_out
4531 -object filter
-redirector
,netdev
=hn0
,id
=redire1
,queue
=rx
,outdev
=compare0
4532 -object colo
-compare
,id
=comp0
,primary_in
=compare0
-0,secondary_in
=compare1
,outdev
=compare_out0
,iothread
=iothread1
4535 -netdev tap
,id
=hn0
,vhost
=off
,script
=/etc
/qemu
-ifup
,down script
=/etc
/qemu
-ifdown
4536 -device e1000
,netdev
=hn0
,mac
=52:a4
:00:12:78:66
4537 -chardev socket
,id
=red0
,host
=3.3.3.3,port
=9003
4538 -chardev socket
,id
=red1
,host
=3.3.3.3,port
=9004
4539 -object filter
-redirector
,id
=f1
,netdev
=hn0
,queue
=tx
,indev
=red0
4540 -object filter
-redirector
,id
=f2
,netdev
=hn0
,queue
=rx
,outdev
=red1
4546 -netdev tap
,id
=hn0
,vhost
=off
,script
=/etc
/qemu
-ifup
,downscript
=/etc
/qemu
-ifdown
4547 -device e1000
,id
=e0
,netdev
=hn0
,mac
=52:a4
:00:12:78:66
4548 -chardev socket
,id
=mirror0
,host
=3.3.3.3,port
=9003,server
,nowait
4549 -chardev socket
,id
=compare1
,host
=3.3.3.3,port
=9004,server
,nowait
4550 -chardev socket
,id
=compare0
,host
=3.3.3.3,port
=9001,server
,nowait
4551 -chardev socket
,id
=compare0
-0,host
=3.3.3.3,port
=9001
4552 -chardev socket
,id
=compare_out
,host
=3.3.3.3,port
=9005,server
,nowait
4553 -chardev socket
,id
=compare_out0
,host
=3.3.3.3,port
=9005
4554 -chardev socket
,id
=notify_way
,host
=3.3.3.3,port
=9009,server
,nowait
4555 -object filter
-mirror
,id
=m0
,netdev
=hn0
,queue
=tx
,outdev
=mirror0
4556 -object filter
-redirector
,netdev
=hn0
,id
=redire0
,queue
=rx
,indev
=compare_out
4557 -object filter
-redirector
,netdev
=hn0
,id
=redire1
,queue
=rx
,outdev
=compare0
4558 -object iothread
,id
=iothread1
4559 -object colo
-compare
,id
=comp0
,primary_in
=compare0
-0,secondary_in
=compare1
,outdev
=compare_out0
,notify_dev
=nofity_way
,iothread
=iothread1
4562 -netdev tap
,id
=hn0
,vhost
=off
,script
=/etc
/qemu
-ifup
,down script
=/etc
/qemu
-ifdown
4563 -device e1000
,netdev
=hn0
,mac
=52:a4
:00:12:78:66
4564 -chardev socket
,id
=red0
,host
=3.3.3.3,port
=9003
4565 -chardev socket
,id
=red1
,host
=3.3.3.3,port
=9004
4566 -object filter
-redirector
,id
=f1
,netdev
=hn0
,queue
=tx
,indev
=red0
4567 -object filter
-redirector
,id
=f2
,netdev
=hn0
,queue
=rx
,outdev
=red1
4571 If you want to know the detail of above command line
, you can read
4572 the colo
-compare git log
.
4574 @item
-object cryptodev
-backend
-builtin
,id
=@
var{id
}[,queues
=@
var{queues
}]
4576 Creates a cryptodev backend which executes crypto opreation from
4577 the QEMU cipher APIS
. The @
var{id
} parameter is
4578 a unique ID that will be used to reference
this cryptodev backend from
4579 the @option
{virtio
-crypto
} device
. The @
var{queues
} parameter is optional
,
4580 which specify the queue number of cryptodev backend
, the
default of
4585 # @value
{qemu_system
} \
4587 -object cryptodev
-backend
-builtin
,id
=cryptodev0 \
4588 -device virtio
-crypto
-pci
,id
=crypto0
,cryptodev
=cryptodev0 \
4592 @item
-object cryptodev
-vhost
-user
,id
=@
var{id
},chardev
=@
var{chardevid
}[,queues
=@
var{queues
}]
4594 Creates a vhost
-user cryptodev backend
, backed by a chardev @
var{chardevid
}.
4595 The @
var{id
} parameter is a unique ID that will be used to reference
this
4596 cryptodev backend from the @option
{virtio
-crypto
} device
.
4597 The chardev should be a unix domain socket backed one
. The vhost
-user uses
4598 a specifically defined protocol to pass vhost ioctl replacement messages
4599 to an application on the other end of the socket
.
4600 The @
var{queues
} parameter is optional
, which specify the queue number
4601 of cryptodev backend
for multiqueue vhost
-user
, the
default of @
var{queues
} is
1.
4605 # @value
{qemu_system
} \
4607 -chardev socket
,id
=chardev0
,path
=/path
/to
/socket \
4608 -object cryptodev
-vhost
-user
,id
=cryptodev0
,chardev
=chardev0 \
4609 -device virtio
-crypto
-pci
,id
=crypto0
,cryptodev
=cryptodev0 \
4613 @item
-object secret
,id
=@
var{id
},data
=@
var{string
},format
=@
var{raw|base64
}[,keyid
=@
var{secretid
},iv
=@
var{string
}]
4614 @item
-object secret
,id
=@
var{id
},file
=@
var{filename
},format
=@
var{raw|base64
}[,keyid
=@
var{secretid
},iv
=@
var{string
}]
4616 Defines a secret to store a password
, encryption key
, or some other sensitive
4617 data
. The sensitive data can either be passed directly via the @
var{data
}
4618 parameter
, or indirectly via the @
var{file
} parameter
. Using the @
var{data
}
4619 parameter is insecure unless the sensitive data is encrypted
.
4621 The sensitive data can be provided
in raw
format (the
default), or base64
.
4622 When encoded as JSON
, the raw format only supports valid UTF
-8 characters
,
4623 so base64 is recommended
for sending binary data
. QEMU will convert from
4624 which ever format is provided to the format it needs internally
. eg
, an
4625 RBD password can be provided
in raw format
, even though it will be base64
4626 encoded when passed onto the RBD sever
.
4628 For added protection
, it is possible to encrypt the data associated with
4629 a secret
using the AES
-256-CBC cipher
. Use of encryption is indicated
4630 by providing the @
var{keyid
} and @
var{iv
} parameters
. The @
var{keyid
}
4631 parameter provides the ID of a previously defined secret that contains
4632 the AES
-256 decryption key
. This key should be
32-bytes long and be
4633 base64 encoded
. The @
var{iv
} parameter provides the random initialization
4634 vector used
for encryption of
this particular secret and should be a
4635 base64 encrypted string of the
16-byte IV
.
4637 The
simplest (insecure
) usage is to provide the secret
inline
4641 # @value
{qemu_system
} -object secret
,id
=sec0
,data
=letmein
,format
=raw
4645 The simplest secure usage is to provide the secret via a file
4647 # printf
"letmein" > mypasswd
.txt
4648 # @value
{qemu_system
} -object secret
,id
=sec0
,file
=mypasswd
.txt
,format
=raw
4650 For greater security
, AES
-256-CBC should be used
. To illustrate usage
,
4651 consider the openssl command line tool which can encrypt the data
. Note
4652 that when encrypting
, the plaintext must be padded to the cipher block
4653 size (32 bytes
) using the standard PKCS#
5/6 compatible padding algorithm
.
4655 First a master key needs to be created
in base64 encoding
:
4658 # openssl rand
-base64
32 > key
.b64
4659 # KEY
=$
(base64
-d key
.b64 | hexdump
-v
-e
'/1 "%02X"')
4662 Each secret to be encrypted needs to have a random initialization vector
4663 generated
. These
do not need to be kept secret
4666 # openssl rand
-base64
16 > iv
.b64
4667 # IV
=$
(base64
-d iv
.b64 | hexdump
-v
-e
'/1 "%02X"')
4670 The secret to be defined can now be encrypted
, in this case we
're
4671 telling openssl to base64 encode the result, but it could be left
4672 as raw bytes if desired.
4675 # SECRET=$(printf "letmein" |
4676 openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4679 When launching QEMU, create a master secret pointing to @code{key.b64}
4680 and specify that to be used to decrypt the user password. Pass the
4681 contents of @code{iv.b64} to the second secret
4684 # @value{qemu_system} \
4685 -object secret,id=secmaster0,format=base64,file=key.b64 \
4686 -object secret,id=sec0,keyid=secmaster0,format=base64,\
4687 data=$SECRET,iv=$(<iv.b64)
4690 @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}]
4692 Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4693 to provide the guest memory encryption support on AMD processors.
4695 When memory encryption is enabled, one of the physical address bit (aka the
4696 C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4697 is used to provide the C-bit position. The C-bit position is Host family dependent
4698 hence user must provide this value. On EPYC, the value should be 47.
4700 When memory encryption is enabled, we loose certain bits in physical address space.
4701 The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4702 physical address space. Similar to C-bit, the value is Host family dependent.
4703 On EPYC, the value should be 5.
4705 The @option{sev-device} provides the device file to use for communicating with
4706 the SEV firmware running inside AMD Secure Processor. The default device is
4707 '/dev
/sev
'. If hardware supports memory encryption then /dev/sev devices are
4708 created by CCP driver.
4710 The @option{policy} provides the guest policy to be enforced by the SEV firmware
4711 and restrict what configuration and operational commands can be performed on this
4712 guest by the hypervisor. The policy should be provided by the guest owner and is
4713 bound to the guest and cannot be changed throughout the lifetime of the guest.
4716 If guest @option{policy} allows sharing the key with another SEV guest then
4717 @option{handle} can be use to provide handle of the guest from which to share
4720 The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4721 Public Diffie
-Hillman key defined
in SEV spec
. The PDH and session parameters
4722 are used
for establishing a cryptographic session with the guest owner to
4723 negotiate keys used
for attestation
. The file must be encoded
in base64
.
4725 e
.g to launch a SEV guest
4727 # @value
{qemu_system_x86
} \
4729 -object sev
-guest
,id
=sev0
,cbitpos
=47,reduced
-phys
-bits
=5 \
4730 -machine
...,memory
-encryption
=sev0
4736 @item
-object authz
-simple
,id
=@
var{id
},identity
=@
var{string
}
4738 Create an authorization object that will control access to network services
.
4740 The @option
{identity
} parameter is identifies the user and its format
4741 depends on the network service that authorization object is associated
4742 with
. For authorizing based on TLS x509 certificates
, the identity must
4743 be the x509 distinguished name
. Note that care must be taken to escape
4744 any commas
in the distinguished name
.
4746 An example authorization object to validate a x509 distinguished name
4749 # @value
{qemu_system
} \
4751 -object
'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \
4755 Note the use of quotes due to the x509 distinguished name containing
4756 whitespace
, and escaping of
','.
4758 @item
-object authz
-listfile
,id
=@
var{id
},filename
=@
var{path
},refresh
=@
var{yes|no
}
4760 Create an authorization object that will control access to network services
.
4762 The @option
{filename
} parameter is the fully qualified path to a file
4763 containing the access control list rules
in JSON format
.
4765 An example set of rules that match against SASL usernames might look
4771 @
{ "match": "fred", "policy": "allow", "format": "exact" @
},
4772 @
{ "match": "bob", "policy": "allow", "format": "exact" @
},
4773 @
{ "match": "danb", "policy": "deny", "format": "glob" @
},
4774 @
{ "match": "dan*", "policy": "allow", "format": "exact" @
},
4780 When checking access the object will iterate over all the rules and
4781 the first rule to match will have its @option
{policy
} value returned
4782 as the result
. If no rules match
, then the
default @option
{policy
}
4785 The rules can either be an exact string match
, or they can use the
4786 simple UNIX glob pattern matching to allow wildcards to be used
.
4788 If @option
{refresh
} is set to
true the file will be monitored
4789 and automatically reloaded whenever its content changes
.
4791 As with the @code
{authz
-simple
} object
, the format of the identity
4792 strings being matched depends on the network service
, but is usually
4793 a TLS x509 distinguished name
, or a SASL username
.
4795 An example authorization object to validate a SASL username
4798 # @value
{qemu_system
} \
4800 -object authz
-simple
,id
=auth0
,filename
=/etc
/qemu
/vnc
-sasl
.acl
,refresh
=yes
4804 @item
-object authz
-pam
,id
=@
var{id
},service
=@
var{string
}
4806 Create an authorization object that will control access to network services
.
4808 The @option
{service
} parameter provides the name of a PAM service to use
4809 for authorization
. It requires that a file @code
{/etc
/pam
.d
/@
var{service
}}
4810 exist to provide the configuration
for the @code
{account
} subsystem
.
4812 An example authorization object to validate a TLS x509 distinguished
4813 name would look like
:
4816 # @value
{qemu_system
} \
4818 -object authz
-pam
,id
=auth0
,service
=qemu
-vnc
4822 There would then be a corresponding config file
for PAM at
4823 @code
{/etc
/pam
.d
/qemu
-vnc
} that contains
:
4826 account requisite pam_listfile
.so item
=user sense
=allow \
4827 file
=/etc
/qemu
/vnc
.allow
4830 Finally the @code
{/etc
/qemu
/vnc
.allow
} file would contain
4831 the list of x509 distingished names that are permitted
4835 CN
=laptop
.example
.com
,O
=Example Home
,L
=London
,ST
=London
,C
=GB
4844 HXCOMM This is the last statement
. Insert
new options before
this line
!