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, 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",
48 @item
-machine
[type
=]@
var{name
}[,prop
=@
var{value
}[,...]]
50 Select the emulated machine by @
var{name
}. Use @code
{-machine help
} to list
51 available machines
. Supported machine properties are
:
53 @item accel
=@
var{accels1
}[:@
var{accels2
}[:...]]
54 This is used to enable an accelerator
. Depending on the target architecture
,
55 kvm
, xen
, or tcg can be available
. By
default, tcg is used
. If there is more
56 than one accelerator specified
, the next one is used
if the previous one fails
58 @item kernel_irqchip
=on|off
59 Controls
in-kernel irqchip support
for the chosen accelerator when available
.
60 @item gfx_passthru
=on|off
61 Enables IGD GFX passthrough support
for the chosen machine when available
.
62 @item vmport
=on|off|auto
63 Enables emulation of VMWare IO port
, for vmmouse etc
. auto says to select the
64 value based on accel
. For accel
=xen the
default is off otherwise the
default
66 @item kvm_shadow_mem
=size
67 Defines the size of the KVM shadow MMU
.
68 @item dump
-guest
-core
=on|off
69 Include guest memory
in a core dump
. The
default is on
.
70 @item mem
-merge
=on|off
71 Enables or disables memory merge support
. This feature
, when supported by
72 the host
, de
-duplicates identical memory pages among VMs instances
74 @item aes
-key
-wrap
=on|off
75 Enables or disables AES key wrapping support on s390
-ccw hosts
. This feature
76 controls whether AES wrapping keys will be created to allow
77 execution of AES cryptographic functions
. The
default is on
.
78 @item dea
-key
-wrap
=on|off
79 Enables or disables DEA key wrapping support on s390
-ccw hosts
. This feature
80 controls whether DEA wrapping keys will be created to allow
81 execution of DEA cryptographic functions
. The
default is on
.
83 Enables or disables NVDIMM support
. The
default is off
.
87 HXCOMM Deprecated by
-machine
88 DEF("M", HAS_ARG
, QEMU_OPTION_M
, "", QEMU_ARCH_ALL
)
90 DEF("cpu", HAS_ARG
, QEMU_OPTION_cpu
,
91 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL
)
93 @item
-cpu @
var{model
}
95 Select CPU
model (@code
{-cpu help
} for list and additional feature selection
)
98 DEF("accel", HAS_ARG
, QEMU_OPTION_accel
,
99 "-accel [accel=]accelerator[,thread=single|multi]\n"
100 " select accelerator ('-accel help for list')\n"
101 " thread=single|multi (enable multi-threaded TCG)", QEMU_ARCH_ALL
)
103 @item
-accel @
var{name
}[,prop
=@
var{value
}[,...]]
105 This is used to enable an accelerator
. Depending on the target architecture
,
106 kvm
, xen
, or tcg can be available
. By
default, tcg is used
. If there is more
107 than one accelerator specified
, the next one is used
if the previous one fails
110 @item thread
=single|multi
111 Controls number of TCG threads
. When the TCG is multi
-threaded there will be one
112 thread per vCPU therefor taking advantage of additional host cores
. The
default
113 is to enable multi
-threading where both the back
-end and front
-ends support it and
114 no incompatible TCG features have been
enabled (e
.g
. icount
/replay
).
118 DEF("smp", HAS_ARG
, QEMU_OPTION_smp
,
119 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]\n"
120 " set the number of CPUs to 'n' [default=1]\n"
121 " maxcpus= maximum number of total cpus, including\n"
122 " offline CPUs for hotplug, etc\n"
123 " cores= number of CPU cores on one socket\n"
124 " threads= number of threads on one CPU core\n"
125 " sockets= number of discrete sockets in the system\n",
128 @item
-smp
[cpus
=]@
var{n
}[,cores
=@
var{cores
}][,threads
=@
var{threads
}][,sockets
=@
var{sockets
}][,maxcpus
=@
var{maxcpus
}]
130 Simulate an SMP system with @
var{n
} CPUs
. On the PC target
, up to
255
131 CPUs are supported
. On Sparc32 target
, Linux limits the number of usable CPUs
133 For the PC target
, the number of @
var{cores
} per socket
, the number
134 of @
var{threads
} per cores and the total number of @
var{sockets
} can be
135 specified
. Missing values will be computed
. If any on the three values is
136 given
, the total number of CPUs @
var{n
} can be omitted
. @
var{maxcpus
}
137 specifies the maximum number of hotpluggable CPUs
.
140 DEF("numa", HAS_ARG
, QEMU_OPTION_numa
,
141 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
142 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n", QEMU_ARCH_ALL
)
144 @item
-numa node
[,mem
=@
var{size
}][,cpus
=@
var{firstcpu
}[-@
var{lastcpu
}]][,nodeid
=@
var{node
}]
145 @itemx
-numa node
[,memdev
=@
var{id
}][,cpus
=@
var{firstcpu
}[-@
var{lastcpu
}]][,nodeid
=@
var{node
}]
147 Define a NUMA node and assign RAM and VCPUs to it
.
149 @
var{firstcpu
} and @
var{lastcpu
} are CPU indexes
. Each
150 @samp
{cpus
} option represent a contiguous range of CPU indexes
151 (or a single VCPU
if @
var{lastcpu
} is omitted
). A non
-contiguous
152 set of VCPUs can be represented by providing multiple @samp
{cpus
}
153 options
. If @samp
{cpus
} is omitted on all nodes
, VCPUs are automatically
156 For example
, the following option assigns VCPUs
0, 1, 2 and
5 to
159 -numa node
,cpus
=0-2,cpus
=5
162 @samp
{mem
} assigns a given RAM amount to a node
. @samp
{memdev
}
163 assigns RAM from a given memory backend device to a node
. If
164 @samp
{mem
} and @samp
{memdev
} are omitted
in all nodes
, RAM is
165 split equally between them
.
167 @samp
{mem
} and @samp
{memdev
} are mutually exclusive
. Furthermore
,
168 if one node uses @samp
{memdev
}, all of them have to use it
.
170 Note that the
-@option
{numa
} option doesn
't allocate any of the
171 specified resources, it just assigns existing resources to NUMA
172 nodes. This means that one still has to use the @option{-m},
173 @option{-smp} options to allocate RAM and VCPUs respectively.
177 DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
178 "-add-fd fd=fd,set=set[,opaque=opaque]\n"
179 " Add 'fd
' to fd 'set
'\n", QEMU_ARCH_ALL)
181 @item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}]
184 Add a file descriptor to an fd set. Valid options are:
188 This option defines the file descriptor of which a duplicate is added to fd set.
189 The file descriptor cannot be stdin, stdout, or stderr.
191 This option defines the ID of the fd set to add the file descriptor to.
192 @item opaque=@var{opaque}
193 This option defines a free-form string that can be used to describe @var{fd}.
196 You can open an image using pre-opened file descriptors from an fd set:
199 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
200 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
201 -drive file=/dev/fdset/2,index=0,media=disk
205 DEF("set", HAS_ARG, QEMU_OPTION_set,
206 "-set group.id.arg=value\n"
207 " set <arg> parameter for item <id> of type <group>\n"
208 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
210 @item -set @var{group}.@var{id}.@var{arg}=@var{value}
212 Set parameter @var{arg} for item @var{id} of type @var{group}
215 DEF("global", HAS_ARG, QEMU_OPTION_global,
216 "-global driver.property=value\n"
217 "-global driver=driver,property=property,value=value\n"
218 " set a global default for a driver property\n",
221 @item -global @var{driver}.@var{prop}=@var{value}
222 @itemx -global driver=@var{driver},property=@var{property},value=@var{value}
224 Set default value of @var{driver}'s property @
var{prop
} to @
var{value
}, e
.g
.:
227 qemu
-system
-i386
-global ide
-drive
.physical_block_size
=4096 -drive file
=file
,if=ide
,index
=0,media
=disk
230 In particular
, you can use
this to set driver properties
for devices which are
231 created automatically by the machine model
. To create a device which is not
232 created automatically and set properties on it
, use
-@option
{device
}.
234 -global @
var{driver
}.@
var{prop
}=@
var{value
} is shorthand
for -global
235 driver
=@
var{driver
},property
=@
var{prop
},value
=@
var{value
}. The
236 longhand syntax works even when @
var{driver
} contains a dot
.
239 DEF("boot", HAS_ARG
, QEMU_OPTION_boot
,
240 "-boot [order=drives][,once=drives][,menu=on|off]\n"
241 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
242 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
243 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
244 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n"
245 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
248 @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
]
250 Specify boot order @
var{drives
} as a string of drive letters
. Valid
251 drive letters depend on the target architecture
. The x86 PC uses
: a
, b
252 (floppy
1 and
2), c (first hard disk
), d (first CD
-ROM
), n
-p (Etherboot
253 from network adapter
1-4), hard disk boot is the
default. To apply a
254 particular boot order only on the first startup
, specify it via
255 @option
{once
}. Note that the @option
{order
} or @option
{once
} parameter
256 should not be used together with the @option
{bootindex
} property of
257 devices
, since the firmware implementations normally
do not support both
260 Interactive boot menus
/prompts can be enabled via @option
{menu
=on
} as far
261 as firmware
/BIOS supports them
. The
default is non
-interactive boot
.
263 A splash picture could be passed to bios
, enabling user to show it as logo
,
264 when option splash
=@
var{sp_name
} is given and menu
=on
, If firmware
/BIOS
265 supports them
. Currently Seabios
for X86 system support it
.
266 limitation
: The splash file could be a jpeg file or a BMP file
in 24 BPP
267 format(true color
). The resolution should be supported by the SVGA mode
, so
268 the recommended is
320x240
, 640x480
, 800x640
.
270 A timeout could be passed to bios
, guest will pause
for @
var{rb_timeout
} ms
271 when boot failed
, then reboot
. If @
var{rb_timeout
} is
'-1', guest will not
272 reboot
, qemu passes
'-1' to bios by
default. Currently Seabios
for X86
275 Do strict boot via @option
{strict
=on
} as far as firmware
/BIOS
276 supports it
. This only effects when boot priority is changed by
277 bootindex options
. The
default is non
-strict boot
.
280 #
try to boot from network first
, then from hard disk
281 qemu
-system
-i386
-boot order
=nc
282 # boot from CD
-ROM first
, switch back to
default order after reboot
283 qemu
-system
-i386
-boot once
=d
284 # boot with a splash picture
for 5 seconds
.
285 qemu
-system
-i386
-boot menu
=on
,splash
=/root
/boot
.bmp
,splash
-time
=5000
288 Note
: The legacy format
'-boot @var{drives}' is still supported but its
289 use is discouraged as it may be removed from future versions
.
292 DEF("m", HAS_ARG
, QEMU_OPTION_m
,
293 "-m [size=]megs[,slots=n,maxmem=size]\n"
294 " configure guest RAM\n"
295 " size: initial amount of guest memory\n"
296 " slots: number of hotplug slots (default: none)\n"
297 " maxmem: maximum amount of guest memory (default: none)\n"
298 "NOTE: Some architectures might enforce a specific granularity\n",
301 @item
-m
[size
=]@
var{megs
}[,slots
=n
,maxmem
=size
]
303 Sets guest startup RAM size to @
var{megs
} megabytes
. Default is
128 MiB
.
304 Optionally
, a suffix of ``M
'' or ``G
'' can be used to signify a value
in
305 megabytes or gigabytes respectively
. Optional pair @
var{slots
}, @
var{maxmem
}
306 could be used to set amount of hotpluggable memory slots and maximum amount of
307 memory
. Note that @
var{maxmem
} must be aligned to the page size
.
309 For example
, the following command
-line sets the guest startup RAM size to
310 1GB
, creates
3 slots to hotplug additional memory and sets the maximum
311 memory the guest can reach to
4GB
:
314 qemu
-system
-x86_64
-m
1G
,slots
=3,maxmem
=4G
317 If @
var{slots
} and @
var{maxmem
} are not specified
, memory hotplug won
't
318 be enabled and the guest startup RAM will never increase.
321 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
322 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
324 @item -mem-path @var{path}
326 Allocate guest RAM from a temporarily created file in @var{path}.
329 DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
330 "-mem-prealloc preallocate guest memory (use with -mem-path)\n",
334 @findex -mem-prealloc
335 Preallocate memory when using -mem-path.
338 DEF("k", HAS_ARG, QEMU_OPTION_k,
339 "-k language use keyboard layout (for example 'fr
' for French)\n",
342 @item -k @var{language}
344 Use keyboard layout @var{language} (for example @code{fr} for
345 French). This option is only needed where it is not easy to get raw PC
346 keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
347 display). You don't normally need to use it on PC
/Linux or PC
/Windows
350 The available layouts are
:
352 ar de
-ch es fo fr
-ca hu ja mk no pt
-br sv
353 da en
-gb et fr fr
-ch is lt nl pl ru th
354 de en
-us fi fr
-be hr it lv nl
-be pt sl tr
357 The
default is @code
{en
-us
}.
361 DEF("audio-help", 0, QEMU_OPTION_audio_help
,
362 "-audio-help print list of audio drivers and their options\n",
367 Will show the audio subsystem help
: list of drivers
, tunable
371 DEF("soundhw", HAS_ARG
, QEMU_OPTION_soundhw
,
372 "-soundhw c1,... enable audio support\n"
373 " and only specified sound cards (comma separated list)\n"
374 " use '-soundhw help' to get the list of supported cards\n"
375 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL
)
377 @item
-soundhw @
var{card1
}[,@
var{card2
},...] or
-soundhw all
379 Enable audio and selected sound hardware
. Use
'help' to print all
380 available sound hardware
.
383 qemu
-system
-i386
-soundhw sb16
,adlib disk
.img
384 qemu
-system
-i386
-soundhw es1370 disk
.img
385 qemu
-system
-i386
-soundhw ac97 disk
.img
386 qemu
-system
-i386
-soundhw hda disk
.img
387 qemu
-system
-i386
-soundhw all disk
.img
388 qemu
-system
-i386
-soundhw help
391 Note that Linux
's i810_audio OSS kernel (for AC97) module might
392 require manually specifying clocking.
395 modprobe i810_audio clocking=48000
399 DEF("balloon", HAS_ARG, QEMU_OPTION_balloon,
400 "-balloon none disable balloon device\n"
401 "-balloon virtio[,addr=str]\n"
402 " enable virtio balloon device (default)\n", QEMU_ARCH_ALL)
406 Disable balloon device.
407 @item -balloon virtio[,addr=@var{addr}]
408 Enable virtio balloon device (default), optionally with PCI address
412 DEF("device", HAS_ARG, QEMU_OPTION_device,
413 "-device driver[,prop[=value][,...]]\n"
414 " add device (based on driver)\n"
415 " prop=value,... sets driver properties\n"
416 " use '-device help
' to print all possible drivers\n"
417 " use '-device driver
,help
' to print all possible properties\n",
420 @item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
422 Add device @var{driver}. @var{prop}=@var{value} sets driver
423 properties. Valid properties depend on the driver. To get help on
424 possible drivers and properties, use @code{-device help} and
425 @code{-device @var{driver},help}.
428 @item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}]
430 Add an IPMI BMC. This is a simulation of a hardware management
431 interface processor that normally sits on a system. It provides
432 a watchdog and the ability to reset and power control the system.
433 You need to connect this to an IPMI interface to make it useful
435 The IPMI slave address to use for the BMC. The default is 0x20.
436 This address is the BMC's address on the I2C network of management
437 controllers
. If you don
't know what this means, it is safe to ignore
442 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
443 @item slave_addr=@var{val}
444 Define slave address to use for the BMC. The default is 0x20.
445 @item sdrfile=@var{file}
446 file containing raw Sensor Data Records (SDR) data. The default is none.
447 @item fruareasize=@var{val}
448 size of a Field Replaceable Unit (FRU) area. The default is 1024.
449 @item frudatafile=@var{file}
450 file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
453 @item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
455 Add a connection to an external IPMI BMC simulator. Instead of
456 locally emulating the BMC like the above item, instead connect
457 to an external entity that provides the IPMI services.
459 A connection is made to an external BMC simulator. If you do this, it
460 is strongly recommended that you use the "reconnect=" chardev option
461 to reconnect to the simulator if the connection is lost. Note that if
462 this is not used carefully, it can be a security issue, as the
463 interface has the ability to send resets, NMIs, and power off the VM.
464 It's best
if QEMU makes a connection to an external simulator running
465 on a secure port on localhost
, so neither the simulator nor QEMU is
466 exposed to any outside network
.
468 See the
"lanserv/README.vm" file
in the OpenIPMI library
for more
469 details on the external
interface.
471 @item
-device isa
-ipmi
-kcs
,bmc
=@
var{id
}[,ioport
=@
var{val
}][,irq
=@
var{val
}]
473 Add a KCS IPMI interafce on the ISA bus
. This also adds a
474 corresponding ACPI and SMBIOS entries
, if appropriate
.
478 The BMC to connect to
, one of ipmi
-bmc
-sim or ipmi
-bmc
-extern above
.
479 @item ioport
=@
var{val
}
480 Define the I
/O address of the
interface. The
default is
0xca0 for KCS
.
482 Define the interrupt to use
. The
default is
5. To disable interrupts
,
486 @item
-device isa
-ipmi
-bt
,bmc
=@
var{id
}[,ioport
=@
var{val
}][,irq
=@
var{val
}]
488 Like the KCS
interface, but defines a BT
interface. The
default port is
489 0xe4 and the
default interrupt is
5.
493 DEF("name", HAS_ARG
, QEMU_OPTION_name
,
494 "-name string1[,process=string2][,debug-threads=on|off]\n"
495 " set the name of the guest\n"
496 " string1 sets the window title and string2 the process name (on Linux)\n"
497 " When debug-threads is enabled, individual threads are given a separate name (on Linux)\n"
498 " NOTE: The thread names are for debugging and not a stable API.\n",
501 @item
-name @
var{name
}
503 Sets the @
var{name
} of the guest
.
504 This name will be displayed
in the SDL window caption
.
505 The @
var{name
} will also be used
for the VNC server
.
506 Also optionally set the top visible process name
in Linux
.
507 Naming of individual threads can also be enabled on Linux to aid debugging
.
510 DEF("uuid", HAS_ARG
, QEMU_OPTION_uuid
,
511 "-uuid %08x-%04x-%04x-%04x-%012x\n"
512 " specify machine UUID\n", QEMU_ARCH_ALL
)
514 @item
-uuid @
var{uuid
}
524 DEFHEADING(Block device options
)
529 DEF("fda", HAS_ARG
, QEMU_OPTION_fda
,
530 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL
)
531 DEF("fdb", HAS_ARG
, QEMU_OPTION_fdb
, "", QEMU_ARCH_ALL
)
533 @item
-fda @
var{file
}
534 @itemx
-fdb @
var{file
}
537 Use @
var{file
} as floppy disk
0/1 image (@pxref
{disk_images
}).
540 DEF("hda", HAS_ARG
, QEMU_OPTION_hda
,
541 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL
)
542 DEF("hdb", HAS_ARG
, QEMU_OPTION_hdb
, "", QEMU_ARCH_ALL
)
543 DEF("hdc", HAS_ARG
, QEMU_OPTION_hdc
,
544 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL
)
545 DEF("hdd", HAS_ARG
, QEMU_OPTION_hdd
, "", QEMU_ARCH_ALL
)
547 @item
-hda @
var{file
}
548 @itemx
-hdb @
var{file
}
549 @itemx
-hdc @
var{file
}
550 @itemx
-hdd @
var{file
}
555 Use @
var{file
} as hard disk
0, 1, 2 or
3 image (@pxref
{disk_images
}).
558 DEF("cdrom", HAS_ARG
, QEMU_OPTION_cdrom
,
559 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
562 @item
-cdrom @
var{file
}
564 Use @
var{file
} as CD
-ROM
image (you cannot use @option
{-hdc
} and
565 @option
{-cdrom
} at the same time
). You can use the host CD
-ROM by
566 using @file
{/dev
/cdrom
} as
filename (@pxref
{host_drives
}).
569 DEF("blockdev", HAS_ARG
, QEMU_OPTION_blockdev
,
570 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
571 " [,cache.direct=on|off][,cache.no-flush=on|off]\n"
572 " [,read-only=on|off][,detect-zeroes=on|off|unmap]\n"
573 " [,driver specific parameters...]\n"
574 " configure a block backend\n", QEMU_ARCH_ALL
)
576 DEF("drive", HAS_ARG
, QEMU_OPTION_drive
,
577 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
578 " [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
579 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
580 " [,serial=s][,addr=A][,rerror=ignore|stop|report]\n"
581 " [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n"
582 " [,readonly=on|off][,copy-on-read=on|off]\n"
583 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
584 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
585 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
586 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
587 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
588 " [[,iops_size=is]]\n"
590 " use 'file' as a drive image\n", QEMU_ARCH_ALL
)
592 @item
-drive @
var{option
}[,@
var{option
}[,@
var{option
}[,...]]]
595 Define a
new drive
. Valid options are
:
598 @item file
=@
var{file
}
599 This option defines which disk
image (@pxref
{disk_images
}) to use with
600 this drive
. If the filename contains comma
, you must double it
601 (for instance
, "file=my,,file" to use file
"my,file").
603 Special files such as iSCSI devices can be specified
using protocol
604 specific URLs
. See the section
for "Device URL Syntax" for more information
.
605 @item
if=@
var{interface}
606 This option defines on which type on
interface the drive is connected
.
607 Available types are
: ide
, scsi
, sd
, mtd
, floppy
, pflash
, virtio
.
608 @item bus
=@
var{bus
},unit
=@
var{unit
}
609 These options define where is connected the drive by defining the bus number and
611 @item index
=@
var{index
}
612 This option defines where is connected the drive by
using an index
in the list
613 of available connectors of a given
interface type
.
614 @item media
=@
var{media
}
615 This option defines the type of the media
: disk or cdrom
.
616 @item cyls
=@
var{c
},heads
=@
var{h
},secs
=@
var{s
}[,trans
=@
var{t
}]
617 These options have the same definition as they have
in @option
{-hdachs
}.
618 @item snapshot
=@
var{snapshot
}
619 @
var{snapshot
} is
"on" or
"off" and controls snapshot mode
for the given drive
620 (see @option
{-snapshot
}).
621 @item cache
=@
var{cache
}
622 @
var{cache
} is
"none", "writeback", "unsafe", "directsync" or
"writethrough" and controls how the host cache is used to access block data
.
624 @
var{aio
} is
"threads", or
"native" and selects between pthread based disk I
/O and native Linux AIO
.
625 @item discard
=@
var{discard
}
626 @
var{discard
} is one of
"ignore" (or
"off") or
"unmap" (or
"on") and controls whether @dfn
{discard
} (also known as @dfn
{trim
} or @dfn
{unmap
}) requests are ignored or passed to the filesystem
. Some machine types may not support discard requests
.
627 @item format
=@
var{format
}
628 Specify which disk @
var{format
} will be used rather than detecting
629 the format
. Can be used to specify format
=raw to avoid interpreting
630 an untrusted format header
.
631 @item serial
=@
var{serial
}
632 This option specifies the serial number to assign to the device
.
633 @item addr
=@
var{addr
}
634 Specify the controller
's PCI address (if=virtio only).
635 @item werror=@var{action},rerror=@var{action}
636 Specify which @var{action} to take on write and read errors. Valid actions are:
637 "ignore" (ignore the error and try to continue), "stop" (pause QEMU),
638 "report" (report the error to the guest), "enospc" (pause QEMU only if the
639 host disk is full; report the error to the guest otherwise).
640 The default setting is @option{werror=enospc} and @option{rerror=report}.
642 Open drive @option{file} as read-only. Guest write attempts will fail.
643 @item copy-on-read=@var{copy-on-read}
644 @var{copy-on-read} is "on" or "off" and enables whether to copy read backing
645 file sectors into the image file.
646 @item detect-zeroes=@var{detect-zeroes}
647 @var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic
648 conversion of plain zero writes by the OS to driver specific optimized
649 zero write commands. You may even choose "unmap" if @var{discard} is set
650 to "unmap" to allow a zero write to be converted to an UNMAP operation.
651 @item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
652 Specify bandwidth throttling limits in bytes per second, either for all request
653 types or for reads or writes only. Small values can lead to timeouts or hangs
654 inside the guest. A safe minimum for disks is 2 MB/s.
655 @item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm}
656 Specify bursts in bytes per second, either for all request types or for reads
657 or writes only. Bursts allow the guest I/O to spike above the limit
659 @item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
660 Specify request rate limits in requests per second, either for all request
661 types or for reads or writes only.
662 @item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
663 Specify bursts in requests per second, either for all request types or for reads
664 or writes only. Bursts allow the guest I/O to spike above the limit
666 @item iops_size=@var{is}
667 Let every @var{is} bytes of a request count as a new request for iops
668 throttling purposes. Use this option to prevent guests from circumventing iops
669 limits by sending fewer but larger requests.
671 Join a throttling quota group with given name @var{g}. All drives that are
672 members of the same group are accounted for together. Use this option to
673 prevent guests from circumventing throttling limits by using many small disks
674 instead of a single larger disk.
677 By default, the @option{cache=writeback} mode is used. It will report data
678 writes as completed as soon as the data is present in the host page cache.
679 This is safe as long as your guest OS makes sure to correctly flush disk caches
680 where needed. If your guest OS does not handle volatile disk write caches
681 correctly and your host crashes or loses power, then the guest may experience
684 For such guests, you should consider using @option{cache=writethrough}. This
685 means that the host page cache will be used to read and write data, but write
686 notification will be sent to the guest only after QEMU has made sure to flush
687 each write to the disk. Be aware that this has a major impact on performance.
689 The host page cache can be avoided entirely with @option{cache=none}. This will
690 attempt to do disk IO directly to the guest's memory
. QEMU may still perform
691 an internal copy of the data
. Note that
this is considered a writeback mode and
692 the guest OS must handle the disk write cache correctly
in order to avoid data
693 corruption on host crashes
.
695 The host page cache can be avoided
while only sending write notifications to
696 the guest when the data has been flushed to the disk
using
697 @option
{cache
=directsync
}.
699 In
case you don
't care about data integrity over host failures, use
700 @option{cache=unsafe}. This option tells QEMU that it never needs to write any
701 data to the disk but can instead keep things in cache. If anything goes wrong,
702 like your host losing power, the disk storage getting disconnected accidentally,
703 etc. your image will most probably be rendered unusable. When using
704 the @option{-snapshot} option, unsafe caching is always used.
706 Copy-on-read avoids accessing the same backing file sectors repeatedly and is
707 useful when the backing file is over a slow network. By default copy-on-read
710 Instead of @option{-cdrom} you can use:
712 qemu-system-i386 -drive file=file,index=2,media=cdrom
715 Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
718 qemu-system-i386 -drive file=file,index=0,media=disk
719 qemu-system-i386 -drive file=file,index=1,media=disk
720 qemu-system-i386 -drive file=file,index=2,media=disk
721 qemu-system-i386 -drive file=file,index=3,media=disk
724 You can open an image using pre-opened file descriptors from an fd set:
727 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
728 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
729 -drive file=/dev/fdset/2,index=0,media=disk
732 You can connect a CDROM to the slave of ide0:
734 qemu-system-i386 -drive file=file,if=ide,index=1,media=cdrom
737 If you don't specify the
"file=" argument
, you define an empty drive
:
739 qemu
-system
-i386
-drive
if=ide
,index
=1,media
=cdrom
742 Instead of @option
{-fda
}, @option
{-fdb
}, you can use
:
744 qemu
-system
-i386
-drive file
=file
,index
=0,if=floppy
745 qemu
-system
-i386
-drive file
=file
,index
=1,if=floppy
748 By
default, @
var{interface} is
"ide" and @
var{index
} is automatically
751 qemu
-system
-i386
-drive file
=a
-drive file
=b
"
755 qemu-system-i386 -hda a -hdb b
759 DEF("mtdblock
", HAS_ARG, QEMU_OPTION_mtdblock,
760 "-mtdblock file use
'file' as on
-board Flash memory image
\n",
763 @item -mtdblock @var{file}
765 Use @var{file} as on-board Flash memory image.
768 DEF("sd
", HAS_ARG, QEMU_OPTION_sd,
769 "-sd file use
'file' as SecureDigital card image
\n", QEMU_ARCH_ALL)
773 Use @var{file} as SecureDigital card image.
776 DEF("pflash
", HAS_ARG, QEMU_OPTION_pflash,
777 "-pflash file use
'file' as a parallel flash image
\n", QEMU_ARCH_ALL)
779 @item -pflash @var{file}
781 Use @var{file} as a parallel flash image.
784 DEF("snapshot
", 0, QEMU_OPTION_snapshot,
785 "-snapshot write to temporary files instead of disk image files
\n",
790 Write to temporary files instead of disk image files. In this case,
791 the raw disk image you use is not written back. You can however force
792 the write back by pressing @key{C-a s} (@pxref{disk_images}).
795 DEF("hdachs
", HAS_ARG, QEMU_OPTION_hdachs, \
796 "-hdachs c
,h
,s
[,t
]\n" \
797 " force hard disk
0 physical geometry and the optional BIOS
\n" \
798 " translation (t
=none or lba
) (usually QEMU can guess them
)\n",
801 @item -hdachs @var{c},@var{h},@var{s},[,@var{t}]
803 Force hard disk 0 physical geometry (1 <= @var{c} <= 16383, 1 <=
804 @var{h} <= 16, 1 <= @var{s} <= 63) and optionally force the BIOS
805 translation mode (@var{t}=none, lba or auto). Usually QEMU can guess
806 all those parameters. This option is deprecated, please use
807 @code{-device ide-hd,cyls=c,heads=h,secs=s,...} instead.
810 DEF("fsdev
", HAS_ARG, QEMU_OPTION_fsdev,
811 "-fsdev fsdriver
,id
=id
[,path
=path
,][security_model
={mapped
-xattr|mapped
-file|passthrough|none
}]\n"
812 " [,writeout
=immediate
][,readonly
][,socket
=socket|sock_fd
=sock_fd
]\n"
813 " [[,throttling
.bps
-total
=b
]|
[[,throttling
.bps
-read
=r
][,throttling
.bps
-write
=w
]]]\n"
814 " [[,throttling
.iops
-total
=i
]|
[[,throttling
.iops
-read
=r
][,throttling
.iops
-write
=w
]]]\n"
815 " [[,throttling
.bps
-total
-max
=bm
]|
[[,throttling
.bps
-read
-max
=rm
][,throttling
.bps
-write
-max
=wm
]]]\n"
816 " [[,throttling
.iops
-total
-max
=im
]|
[[,throttling
.iops
-read
-max
=irm
][,throttling
.iops
-write
-max
=iwm
]]]\n"
817 " [[,throttling
.iops
-size
=is
]]\n",
822 @item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}]
824 Define a new file system device. Valid options are:
827 This option specifies the fs driver backend to use.
828 Currently "local
", "handle
" and "proxy
" file system drivers are supported.
830 Specifies identifier for this device
831 @item path=@var{path}
832 Specifies the export path for the file system device. Files under
833 this path will be available to the 9p client on the guest.
834 @item security_model=@var{security_model}
835 Specifies the security model to be used for this export path.
836 Supported security models are "passthrough
", "mapped
-xattr
", "mapped
-file
" and "none
".
837 In "passthrough
" security model, files are stored using the same
838 credentials as they are created on the guest. This requires QEMU
839 to run as root. In "mapped
-xattr
" security model, some of the file
840 attributes like uid, gid, mode bits and link target are stored as
841 file attributes. For "mapped
-file
" these attributes are stored in the
842 hidden .virtfs_metadata directory. Directories exported by this security model cannot
843 interact with other unix tools. "none
" security model is same as
844 passthrough except the sever won't report failures if it fails to
845 set file attributes like ownership. Security model is mandatory
846 only for local fsdriver. Other fsdrivers (like handle, proxy) don't take
847 security model as a parameter.
848 @item writeout=@var{writeout}
849 This is an optional argument. The only supported value is "immediate
".
850 This means that host page cache will be used to read and write data but
851 write notification will be sent to the guest only when the data has been
852 reported as written by the storage subsystem.
854 Enables exporting 9p share as a readonly mount for guests. By default
855 read-write access is given.
856 @item socket=@var{socket}
857 Enables proxy filesystem driver to use passed socket file for communicating
858 with virtfs-proxy-helper
859 @item sock_fd=@var{sock_fd}
860 Enables proxy filesystem driver to use passed socket descriptor for
861 communicating with virtfs-proxy-helper. Usually a helper like libvirt
862 will create socketpair and pass one of the fds as sock_fd
865 -fsdev option is used along with -device driver "virtio
-9p
-pci
".
866 @item -device virtio-9p-pci,fsdev=@var{id},mount_tag=@var{mount_tag}
867 Options for virtio-9p-pci driver are:
870 Specifies the id value specified along with -fsdev option
871 @item mount_tag=@var{mount_tag}
872 Specifies the tag name to be used by the guest to mount this export point
877 DEF("virtfs
", HAS_ARG, QEMU_OPTION_virtfs,
878 "-virtfs local
,path
=path
,mount_tag
=tag
,security_model
=[mapped
-xattr|mapped
-file|passthrough|none
]\n"
879 " [,writeout
=immediate
][,readonly
][,socket
=socket|sock_fd
=sock_fd
]\n",
884 @item -virtfs @var{fsdriver}[,path=@var{path}],mount_tag=@var{mount_tag}[,security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}]
887 The general form of a Virtual File system pass-through options are:
890 This option specifies the fs driver backend to use.
891 Currently "local
", "handle
" and "proxy
" file system drivers are supported.
893 Specifies identifier for this device
894 @item path=@var{path}
895 Specifies the export path for the file system device. Files under
896 this path will be available to the 9p client on the guest.
897 @item security_model=@var{security_model}
898 Specifies the security model to be used for this export path.
899 Supported security models are "passthrough
", "mapped
-xattr
", "mapped
-file
" and "none
".
900 In "passthrough
" security model, files are stored using the same
901 credentials as they are created on the guest. This requires QEMU
902 to run as root. In "mapped
-xattr
" security model, some of the file
903 attributes like uid, gid, mode bits and link target are stored as
904 file attributes. For "mapped
-file
" these attributes are stored in the
905 hidden .virtfs_metadata directory. Directories exported by this security model cannot
906 interact with other unix tools. "none
" security model is same as
907 passthrough except the sever won't report failures if it fails to
908 set file attributes like ownership. Security model is mandatory only
909 for local fsdriver. Other fsdrivers (like handle, proxy) don't take security
910 model as a parameter.
911 @item writeout=@var{writeout}
912 This is an optional argument. The only supported value is "immediate
".
913 This means that host page cache will be used to read and write data but
914 write notification will be sent to the guest only when the data has been
915 reported as written by the storage subsystem.
917 Enables exporting 9p share as a readonly mount for guests. By default
918 read-write access is given.
919 @item socket=@var{socket}
920 Enables proxy filesystem driver to use passed socket file for
921 communicating with virtfs-proxy-helper. Usually a helper like libvirt
922 will create socketpair and pass one of the fds as sock_fd
924 Enables proxy filesystem driver to use passed 'sock_fd' as the socket
925 descriptor for interfacing with virtfs-proxy-helper
929 DEF("virtfs_synth
", 0, QEMU_OPTION_virtfs_synth,
930 "-virtfs_synth Create synthetic file system image
\n",
934 @findex -virtfs_synth
935 Create synthetic file system image
943 DEFHEADING(USB options)
948 DEF("usb
", 0, QEMU_OPTION_usb,
949 "-usb enable the USB
driver (will be the
default soon
)\n",
954 Enable the USB driver (will be the default soon)
957 DEF("usbdevice
", HAS_ARG, QEMU_OPTION_usbdevice,
958 "-usbdevice name add the host or guest USB device
'name'\n",
962 @item -usbdevice @var{devname}
964 Add the USB device @var{devname}. @xref{usb_devices}.
969 Virtual Mouse. This will override the PS/2 mouse emulation when activated.
972 Pointer device that uses absolute coordinates (like a touchscreen). This
973 means QEMU is able to report the mouse position without having to grab the
974 mouse. Also overrides the PS/2 mouse emulation when activated.
976 @item disk:[format=@var{format}]:@var{file}
977 Mass storage device based on file. The optional @var{format} argument
978 will be used rather than detecting the format. Can be used to specify
979 @code{format=raw} to avoid interpreting an untrusted format header.
981 @item host:@var{bus}.@var{addr}
982 Pass through the host device identified by @var{bus}.@var{addr} (Linux only).
984 @item host:@var{vendor_id}:@var{product_id}
985 Pass through the host device identified by @var{vendor_id}:@var{product_id}
988 @item serial:[vendorid=@var{vendor_id}][,productid=@var{product_id}]:@var{dev}
989 Serial converter to host character device @var{dev}, see @code{-serial} for the
993 Braille device. This will use BrlAPI to display the braille output on a real
996 @item net:@var{options}
997 Network adapter that supports CDC ethernet and RNDIS protocols.
1007 DEFHEADING(Display options)
1012 DEF("display
", HAS_ARG, QEMU_OPTION_display,
1013 "-display sdl
[,frame
=on|off
][,alt_grab
=on|off
][,ctrl_grab
=on|off
]\n"
1014 " [,window_close
=on|off
][,gl
=on|off
]\n"
1015 "-display gtk
[,grab_on_hover
=on|off
][,gl
=on|off
]|
\n"
1016 "-display vnc
=<display
>[,<optargs
>]\n"
1019 " select display type
\n"
1020 "The
default display is equivalent to
\n"
1021 #if defined(CONFIG_GTK)
1022 "\t\"-display gtk
\"\n"
1023 #elif defined(CONFIG_SDL)
1024 "\t\"-display sdl
\"\n"
1025 #elif defined(CONFIG_COCOA)
1026 "\t\"-display cocoa
\"\n"
1027 #elif defined(CONFIG_VNC)
1028 "\t\"-vnc localhost
:0,to
=99,id
=default\"\n"
1030 "\t\"-display none
\"\n"
1034 @item -display @var{type}
1036 Select type of display to use. This option is a replacement for the
1037 old style -sdl/-curses/... options. Valid values for @var{type} are
1040 Display video output via SDL (usually in a separate graphics
1041 window; see the SDL documentation for other possibilities).
1043 Display video output via curses. For graphics device models which
1044 support a text mode, QEMU can display this output using a
1045 curses/ncurses interface. Nothing is displayed when the graphics
1046 device is in graphical mode or if the graphics device does not support
1047 a text mode. Generally only the VGA device models support text mode.
1049 Do not display video output. The guest will still see an emulated
1050 graphics card, but its output will not be displayed to the QEMU
1051 user. This option differs from the -nographic option in that it
1052 only affects what is done with video output; -nographic also changes
1053 the destination of the serial and parallel port data.
1055 Display video output in a GTK window. This interface provides drop-down
1056 menus and other UI elements to configure and control the VM during
1059 Start a VNC server on display <arg>
1063 DEF("nographic
", 0, QEMU_OPTION_nographic,
1064 "-nographic disable graphical output and redirect serial I
/Os to console
\n",
1069 Normally, if QEMU is compiled with graphical window support, it displays
1070 output such as guest graphics, guest console, and the QEMU monitor in a
1071 window. With this option, you can totally disable graphical output so
1072 that QEMU is a simple command line application. The emulated serial port
1073 is redirected on the console and muxed with the monitor (unless
1074 redirected elsewhere explicitly). Therefore, you can still use QEMU to
1075 debug a Linux kernel with a serial console. Use @key{C-a h} for help on
1076 switching between the console and monitor.
1079 DEF("curses
", 0, QEMU_OPTION_curses,
1080 "-curses shorthand
for -display curses
\n",
1085 Normally, if QEMU is compiled with graphical window support, it displays
1086 output such as guest graphics, guest console, and the QEMU monitor in a
1087 window. With this option, QEMU can display the VGA output when in text
1088 mode using a curses/ncurses interface. Nothing is displayed in graphical
1092 DEF("no
-frame
", 0, QEMU_OPTION_no_frame,
1093 "-no
-frame open SDL window without a frame and window decorations
\n",
1098 Do not use decorations for SDL windows and start them using the whole
1099 available screen space. This makes the using QEMU in a dedicated desktop
1100 workspace more convenient.
1103 DEF("alt
-grab
", 0, QEMU_OPTION_alt_grab,
1104 "-alt
-grab use Ctrl
-Alt
-Shift to grab
mouse (instead of Ctrl
-Alt
)\n",
1109 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
1110 affects the special keys (for fullscreen, monitor-mode switching, etc).
1113 DEF("ctrl
-grab
", 0, QEMU_OPTION_ctrl_grab,
1114 "-ctrl
-grab use Right
-Ctrl to grab
mouse (instead of Ctrl
-Alt
)\n",
1119 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
1120 affects the special keys (for fullscreen, monitor-mode switching, etc).
1123 DEF("no
-quit
", 0, QEMU_OPTION_no_quit,
1124 "-no
-quit disable SDL window close capability
\n", QEMU_ARCH_ALL)
1128 Disable SDL window close capability.
1131 DEF("sdl
", 0, QEMU_OPTION_sdl,
1132 "-sdl shorthand
for -display sdl
\n", QEMU_ARCH_ALL)
1139 DEF("spice
", HAS_ARG, QEMU_OPTION_spice,
1140 "-spice
[port
=port
][,tls
-port
=secured
-port
][,x509
-dir
=<dir
>]\n"
1141 " [,x509
-key
-file
=<file
>][,x509
-key
-password
=<file
>]\n"
1142 " [,x509
-cert
-file
=<file
>][,x509
-cacert
-file
=<file
>]\n"
1143 " [,x509
-dh
-key
-file
=<file
>][,addr
=addr
][,ipv4|ipv6|unix
]\n"
1144 " [,tls
-ciphers
=<list
>]\n"
1145 " [,tls
-channel
=[main|display|cursor|inputs|record|playback
]]\n"
1146 " [,plaintext
-channel
=[main|display|cursor|inputs|record|playback
]]\n"
1147 " [,sasl
][,password
=<secret
>][,disable
-ticketing
]\n"
1148 " [,image
-compression
=[auto_glz|auto_lz|quic|glz|lz|off
]]\n"
1149 " [,jpeg
-wan
-compression
=[auto|
never|always
]]\n"
1150 " [,zlib
-glz
-wan
-compression
=[auto|
never|always
]]\n"
1151 " [,streaming
-video
=[off|all|filter
]][,disable
-copy
-paste
]\n"
1152 " [,disable
-agent
-file
-xfer
][,agent
-mouse
=[on|off
]]\n"
1153 " [,playback
-compression
=[on|off
]][,seamless
-migration
=[on|off
]]\n"
1154 " [,gl
=[on|off
]][,rendernode
=<file
>]\n"
1156 " at least one of
{port
, tls
-port
} is mandatory
\n",
1159 @item -spice @var{option}[,@var{option}[,...]]
1161 Enable the spice remote desktop protocol. Valid options are
1166 Set the TCP port spice is listening on for plaintext channels.
1169 Set the IP address spice is listening on. Default is any address.
1174 Force using the specified IP version.
1176 @item password=<secret>
1177 Set the password you need to authenticate.
1180 Require that the client use SASL to authenticate with the spice.
1181 The exact choice of authentication method used is controlled from the
1182 system / user's SASL configuration file for the 'qemu' service. This
1183 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1184 unprivileged user, an environment variable SASL_CONF_PATH can be used
1185 to make it search alternate locations for the service config.
1186 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1187 it is recommended that SASL always be combined with the 'tls' and
1188 'x509' settings to enable use of SSL and server certificates. This
1189 ensures a data encryption preventing compromise of authentication
1192 @item disable-ticketing
1193 Allow client connects without authentication.
1195 @item disable-copy-paste
1196 Disable copy paste between the client and the guest.
1198 @item disable-agent-file-xfer
1199 Disable spice-vdagent based file-xfer between the client and the guest.
1202 Set the TCP port spice is listening on for encrypted channels.
1204 @item x509-dir=<dir>
1205 Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1207 @item x509-key-file=<file>
1208 @itemx x509-key-password=<file>
1209 @itemx x509-cert-file=<file>
1210 @itemx x509-cacert-file=<file>
1211 @itemx x509-dh-key-file=<file>
1212 The x509 file names can also be configured individually.
1214 @item tls-ciphers=<list>
1215 Specify which ciphers to use.
1217 @item tls-channel=[main|display|cursor|inputs|record|playback]
1218 @itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1219 Force specific channel to be used with or without TLS encryption. The
1220 options can be specified multiple times to configure multiple
1221 channels. The special name "default" can be used to set the default
1222 mode. For channels which are not explicitly forced into one mode the
1223 spice client is allowed to pick tls/plaintext as he pleases.
1225 @item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1226 Configure image compression (lossless).
1227 Default is auto_glz.
1229 @item jpeg-wan-compression=[auto|never|always]
1230 @itemx zlib-glz-wan-compression=[auto|never|always]
1231 Configure wan image compression (lossy for slow links).
1234 @item streaming-video=[off|all|filter]
1235 Configure video stream detection. Default is off.
1237 @item agent-mouse=[on|off]
1238 Enable/disable passing mouse events via vdagent. Default is on.
1240 @item playback-compression=[on|off]
1241 Enable/disable audio stream compression (using celt 0.5.1). Default is on.
1243 @item seamless-migration=[on|off]
1244 Enable/disable spice seamless migration. Default is off.
1247 Enable/disable OpenGL context. Default is off.
1249 @item rendernode=<file>
1250 DRM render node for OpenGL rendering. If not specified, it will pick
1251 the first available. (Since 2.9)
1256 DEF("portrait
", 0, QEMU_OPTION_portrait,
1257 "-portrait rotate graphical output
90 deg
left (only PXA LCD
)\n",
1262 Rotate graphical output 90 deg left (only PXA LCD).
1265 DEF("rotate
", HAS_ARG, QEMU_OPTION_rotate,
1266 "-rotate
<deg
> rotate graphical output some deg
left (only PXA LCD
)\n",
1269 @item -rotate @var{deg}
1271 Rotate graphical output some deg left (only PXA LCD).
1274 DEF("vga
", HAS_ARG, QEMU_OPTION_vga,
1275 "-vga
[std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none
]\n"
1276 " select video card type
\n", QEMU_ARCH_ALL)
1278 @item -vga @var{type}
1280 Select type of VGA card to emulate. Valid values for @var{type} are
1283 Cirrus Logic GD5446 Video card. All Windows versions starting from
1284 Windows 95 should recognize and use this graphic card. For optimal
1285 performances, use 16 bit color depth in the guest and the host OS.
1286 (This card was the default before QEMU 2.2)
1288 Standard VGA card with Bochs VBE extensions. If your guest OS
1289 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1290 to use high resolution modes (>= 1280x1024x16) then you should use
1291 this option. (This card is the default since QEMU 2.2)
1293 VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1294 recent XFree86/XOrg server or Windows guest with a driver for this
1297 QXL paravirtual graphic card. It is VGA compatible (including VESA
1298 2.0 VBE support). Works best with qxl guest drivers installed though.
1299 Recommended choice when using the spice protocol.
1301 (sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1302 sun4m machines and offers both 8-bit and 24-bit colour depths at a
1303 fixed resolution of 1024x768.
1305 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1306 for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1307 resolutions aimed at people wishing to run older Solaris versions.
1315 DEF("full
-screen
", 0, QEMU_OPTION_full_screen,
1316 "-full
-screen start
in full screen
\n", QEMU_ARCH_ALL)
1319 @findex -full-screen
1320 Start in full screen.
1323 DEF("g
", 1, QEMU_OPTION_g ,
1324 "-g WxH
[xDEPTH
] Set the initial graphical resolution and depth
\n",
1325 QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
1327 @item -g @var{width}x@var{height}[x@var{depth}]
1329 Set the initial graphical resolution and depth (PPC, SPARC only).
1332 DEF("vnc
", HAS_ARG, QEMU_OPTION_vnc ,
1333 "-vnc
<display
> shorthand
for -display vnc
=<display
>\n", QEMU_ARCH_ALL)
1335 @item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1337 Normally, if QEMU is compiled with graphical window support, it displays
1338 output such as guest graphics, guest console, and the QEMU monitor in a
1339 window. With this option, you can have QEMU listen on VNC display
1340 @var{display} and redirect the VGA display over the VNC session. It is
1341 very useful to enable the usb tablet device when using this option
1342 (option @option{-usbdevice tablet}). When using the VNC display, you
1343 must use the @option{-k} parameter to set the keyboard layout if you are
1344 not using en-us. Valid syntax for the @var{display} is
1350 With this option, QEMU will try next available VNC @var{display}s, until the
1351 number @var{L}, if the origianlly defined "-vnc @
var{display
}" is not
1352 available, e.g. port 5900+@var{display} is already used by another
1353 application. By default, to=0.
1355 @item @var{host}:@var{d}
1357 TCP connections will only be allowed from @var{host} on display @var{d}.
1358 By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1359 be omitted in which case the server will accept connections from any host.
1361 @item unix:@var{path}
1363 Connections will be allowed over UNIX domain sockets where @var{path} is the
1364 location of a unix socket to listen for connections on.
1368 VNC is initialized but not started. The monitor @code{change} command
1369 can be used to later start the VNC server.
1373 Following the @var{display} value there may be one or more @var{option} flags
1374 separated by commas. Valid options are
1380 Connect to a listening VNC client via a ``reverse'' connection. The
1381 client is specified by the @var{display}. For reverse network
1382 connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
1383 is a TCP port number, not a display number.
1387 Opens an additional TCP listening port dedicated to VNC Websocket connections.
1388 If a bare @var{websocket} option is given, the Websocket port is
1389 5700+@var{display}. An alternative port can be specified with the
1390 syntax @code{websocket}=@var{port}.
1392 If @var{host} is specified connections will only be allowed from this host.
1393 It is possible to control the websocket listen address independently, using
1394 the syntax @code{websocket}=@var{host}:@var{port}.
1396 If no TLS credentials are provided, the websocket connection runs in
1397 unencrypted mode. If TLS credentials are provided, the websocket connection
1398 requires encrypted client connections.
1402 Require that password based authentication is used for client connections.
1404 The password must be set separately using the @code{set_password} command in
1405 the @ref{pcsys_monitor}. The syntax to change your password is:
1406 @code{set_password <protocol> <password>} where <protocol> could be either
1409 If you would like to change <protocol> password expiration, you should use
1410 @code{expire_password <protocol> <expiration-time>} where expiration time could
1411 be one of the following options: now, never, +seconds or UNIX time of
1412 expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
1413 to make password expire on "Mon Apr
23 12:00:00 EDT
2012" (UNIX time for this
1416 You can also use keywords "now
" or "never" for the expiration time to
1417 allow <protocol> password to expire immediately or never expire.
1419 @item tls-creds=@var{ID}
1421 Provides the ID of a set of TLS credentials to use to secure the
1422 VNC server. They will apply to both the normal VNC server socket
1423 and the websocket socket (if enabled). Setting TLS credentials
1424 will cause the VNC server socket to enable the VeNCrypt auth
1425 mechanism. The credentials should have been previously created
1426 using the @option{-object tls-creds} argument.
1428 The @option{tls-creds} parameter obsoletes the @option{tls},
1429 @option{x509}, and @option{x509verify} options, and as such
1430 it is not permitted to set both new and old type options at
1435 Require that client use TLS when communicating with the VNC server. This
1436 uses anonymous TLS credentials so is susceptible to a man-in-the-middle
1437 attack. It is recommended that this option be combined with either the
1438 @option{x509} or @option{x509verify} options.
1440 This option is now deprecated in favor of using the @option{tls-creds}
1443 @item x509=@var{/path/to/certificate/dir}
1445 Valid if @option{tls} is specified. Require that x509 credentials are used
1446 for negotiating the TLS session. The server will send its x509 certificate
1447 to the client. It is recommended that a password be set on the VNC server
1448 to provide authentication of the client when this is used. The path following
1449 this option specifies where the x509 certificates are to be loaded from.
1450 See the @ref{vnc_security} section for details on generating certificates.
1452 This option is now deprecated in favour of using the @option{tls-creds}
1455 @item x509verify=@var{/path/to/certificate/dir}
1457 Valid if @option{tls} is specified. Require that x509 credentials are used
1458 for negotiating the TLS session. The server will send its x509 certificate
1459 to the client, and request that the client send its own x509 certificate.
1460 The server will validate the client's certificate against the CA certificate,
1461 and reject clients when validation fails. If the certificate authority is
1462 trusted, this is a sufficient authentication mechanism. You may still wish
1463 to set a password on the VNC server as a second authentication layer. The
1464 path following this option specifies where the x509 certificates are to
1465 be loaded from. See the @ref{vnc_security} section for details on generating
1468 This option is now deprecated in favour of using the @option{tls-creds}
1473 Require that the client use SASL to authenticate with the VNC server.
1474 The exact choice of authentication method used is controlled from the
1475 system / user's SASL configuration file for the 'qemu' service. This
1476 is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1477 unprivileged user, an environment variable SASL_CONF_PATH can be used
1478 to make it search alternate locations for the service config.
1479 While some SASL auth methods can also provide data encryption (eg GSSAPI),
1480 it is recommended that SASL always be combined with the 'tls' and
1481 'x509' settings to enable use of SSL and server certificates. This
1482 ensures a data encryption preventing compromise of authentication
1483 credentials. See the @ref{vnc_security} section for details on using
1484 SASL authentication.
1488 Turn on access control lists for checking of the x509 client certificate
1489 and SASL party. For x509 certs, the ACL check is made against the
1490 certificate's distinguished name. This is something that looks like
1491 @code{C=GB,O=ACME,L=Boston,CN=bob}. For SASL party, the ACL check is
1492 made against the username, which depending on the SASL plugin, may
1493 include a realm component, eg @code{bob} or @code{bob@@EXAMPLE.COM}.
1494 When the @option{acl} flag is set, the initial access list will be
1495 empty, with a @code{deny} policy. Thus no one will be allowed to
1496 use the VNC server until the ACLs have been loaded. This can be
1497 achieved using the @code{acl} monitor command.
1501 Enable lossy compression methods (gradient, JPEG, ...). If this
1502 option is set, VNC client may receive lossy framebuffer updates
1503 depending on its encoding settings. Enabling this option can save
1504 a lot of bandwidth at the expense of quality.
1508 Disable adaptive encodings. Adaptive encodings are enabled by default.
1509 An adaptive encoding will try to detect frequently updated screen regions,
1510 and send updates in these regions using a lossy encoding (like JPEG).
1511 This can be really helpful to save bandwidth when playing videos. Disabling
1512 adaptive encodings restores the original static behavior of encodings
1515 @item share=[allow-exclusive|force-shared|ignore]
1517 Set display sharing policy. 'allow-exclusive' allows clients to ask
1518 for exclusive access. As suggested by the rfb spec this is
1519 implemented by dropping other connections. Connecting multiple
1520 clients in parallel requires all clients asking for a shared session
1521 (vncviewer: -shared switch). This is the default. 'force-shared'
1522 disables exclusive client access. Useful for shared desktop sessions,
1523 where you don't want someone forgetting specify -shared disconnect
1524 everybody else. 'ignore' completely ignores the shared flag and
1525 allows everybody connect unconditionally. Doesn't conform to the rfb
1526 spec but is traditional QEMU behavior.
1530 Set keyboard delay, for key down and key up events, in milliseconds.
1531 Default is 1. Keyboards are low-bandwidth devices, so this slowdown
1532 can help the device and guest to keep up and not lose events in case
1533 events are arriving in bulk. Possible causes for the latter are flaky
1534 network connections, or scripts for automated testing.
1542 ARCHHEADING(, QEMU_ARCH_I386)
1544 ARCHHEADING(i386 target only, QEMU_ARCH_I386)
1549 DEF("win2k
-hack
", 0, QEMU_OPTION_win2k_hack,
1550 "-win2k
-hack use it when installing Windows
2000 to avoid a disk full bug
\n",
1555 Use it when installing Windows 2000 to avoid a disk full bug. After
1556 Windows 2000 is installed, you no longer need this option (this option
1557 slows down the IDE transfers).
1560 HXCOMM Deprecated by -rtc
1561 DEF("rtc
-td
-hack
", 0, QEMU_OPTION_rtc_td_hack, "", QEMU_ARCH_I386)
1563 DEF("no
-fd
-bootchk
", 0, QEMU_OPTION_no_fd_bootchk,
1564 "-no
-fd
-bootchk disable boot signature checking
for floppy disks
\n",
1567 @item -no-fd-bootchk
1568 @findex -no-fd-bootchk
1569 Disable boot signature checking for floppy disks in BIOS. May
1570 be needed to boot from old floppy disks.
1573 DEF("no
-acpi
", 0, QEMU_OPTION_no_acpi,
1574 "-no
-acpi disable ACPI
\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1578 Disable ACPI (Advanced Configuration and Power Interface) support. Use
1579 it if your guest OS complains about ACPI problems (PC target machine
1583 DEF("no
-hpet
", 0, QEMU_OPTION_no_hpet,
1584 "-no
-hpet disable HPET
\n", QEMU_ARCH_I386)
1588 Disable HPET support.
1591 DEF("acpitable
", HAS_ARG, QEMU_OPTION_acpitable,
1592 "-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"
1593 " ACPI table description
\n", QEMU_ARCH_I386)
1595 @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}]...]
1597 Add ACPI table with specified header fields and context from specified files.
1598 For file=, take whole ACPI table from the specified files, including all
1599 ACPI headers (possible overridden by other options).
1600 For data=, only data
1601 portion of the table is used, all header information is specified in the
1603 If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id
1604 fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
1605 to ensure the field matches required by the Microsoft SLIC spec and the ACPI
1609 DEF("smbios
", HAS_ARG, QEMU_OPTION_smbios,
1610 "-smbios file
=binary
\n"
1611 " load SMBIOS entry from binary file
\n"
1612 "-smbios type
=0[,vendor
=str
][,version
=str
][,date
=str
][,release
=%d
.%d
]\n"
1614 " specify SMBIOS type
0 fields
\n"
1615 "-smbios type
=1[,manufacturer
=str
][,product
=str
][,version
=str
][,serial
=str
]\n"
1616 " [,uuid
=uuid
][,sku
=str
][,family
=str
]\n"
1617 " specify SMBIOS type
1 fields
\n"
1618 "-smbios type
=2[,manufacturer
=str
][,product
=str
][,version
=str
][,serial
=str
]\n"
1619 " [,asset
=str
][,location
=str
]\n"
1620 " specify SMBIOS type
2 fields
\n"
1621 "-smbios type
=3[,manufacturer
=str
][,version
=str
][,serial
=str
][,asset
=str
]\n"
1623 " specify SMBIOS type
3 fields
\n"
1624 "-smbios type
=4[,sock_pfx
=str
][,manufacturer
=str
][,version
=str
][,serial
=str
]\n"
1625 " [,asset
=str
][,part
=str
]\n"
1626 " specify SMBIOS type
4 fields
\n"
1627 "-smbios type
=17[,loc_pfx
=str
][,bank
=str
][,manufacturer
=str
][,serial
=str
]\n"
1628 " [,asset
=str
][,part
=str
][,speed
=%d
]\n"
1629 " specify SMBIOS type
17 fields
\n",
1630 QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1632 @item -smbios file=@var{binary}
1634 Load SMBIOS entry from binary file.
1636 @item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
1637 Specify SMBIOS type 0 fields
1639 @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}]
1640 Specify SMBIOS type 1 fields
1642 @item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}][,family=@var{str}]
1643 Specify SMBIOS type 2 fields
1645 @item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
1646 Specify SMBIOS type 3 fields
1648 @item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
1649 Specify SMBIOS type 4 fields
1651 @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}]
1652 Specify SMBIOS type 17 fields
1660 DEFHEADING(Network options)
1665 HXCOMM Legacy slirp options (now moved to -net user):
1667 DEF("tftp
", HAS_ARG, QEMU_OPTION_tftp, "", QEMU_ARCH_ALL)
1668 DEF("bootp
", HAS_ARG, QEMU_OPTION_bootp, "", QEMU_ARCH_ALL)
1669 DEF("redir
", HAS_ARG, QEMU_OPTION_redir, "", QEMU_ARCH_ALL)
1671 DEF("smb
", HAS_ARG, QEMU_OPTION_smb, "", QEMU_ARCH_ALL)
1675 DEF("netdev
", HAS_ARG, QEMU_OPTION_netdev,
1677 "-netdev user
,id
=str
[,ipv4
[=on|off
]][,net
=addr
[/mask
]][,host
=addr
]\n"
1678 " [,ipv6
[=on|off
]][,ipv6
-net
=addr
[/int
]][,ipv6
-host
=addr
]\n"
1679 " [,restrict
=on|off
][,hostname
=host
][,dhcpstart
=addr
]\n"
1680 " [,dns
=addr
][,ipv6
-dns
=addr
][,dnssearch
=domain
][,tftp
=dir
]\n"
1681 " [,bootfile
=f
][,hostfwd
=rule
][,guestfwd
=rule
]"
1683 "[,smb
=dir
[,smbserver
=addr
]]\n"
1685 " configure a user mode network backend with ID
'str',\n"
1686 " its DHCP server and optional services
\n"
1689 "-netdev tap
,id
=str
,ifname
=name
\n"
1690 " configure a host TAP network backend with ID
'str'\n"
1692 "-netdev tap
,id
=str
[,fd
=h
][,fds
=x
:y
:...:z
][,ifname
=name
][,script
=file
][,downscript
=dfile
]\n"
1693 " [,br
=bridge
][,helper
=helper
][,sndbuf
=nbytes
][,vnet_hdr
=on|off
][,vhost
=on|off
]\n"
1694 " [,vhostfd
=h
][,vhostfds
=x
:y
:...:z
][,vhostforce
=on|off
][,queues
=n
]\n"
1696 " configure a host TAP network backend with ID
'str'\n"
1697 " connected to a
bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1698 " use network scripts
'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
1699 " to configure it and
'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
1700 " to deconfigure it
\n"
1701 " use
'[down]script=no' to disable script execution
\n"
1702 " use network helper
'helper' (default=" DEFAULT_BRIDGE_HELPER ") to
\n"
1704 " use
'fd=h' to connect to an already opened TAP
interface\n"
1705 " use
'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces
\n"
1706 " use
'sndbuf=nbytes' to limit the size of the send
buffer (the
\n"
1707 " default is disabled
'sndbuf=0' to enable flow control set
'sndbuf=1048576')\n"
1708 " use vnet_hdr
=off to avoid enabling the IFF_VNET_HDR tap flag
\n"
1709 " use vnet_hdr
=on to make the lack of IFF_VNET_HDR support an error condition
\n"
1710 " use vhost
=on to enable experimental
in kernel accelerator
\n"
1711 " (only has effect
for virtio guests which use MSIX
)\n"
1712 " use vhostforce
=on to force vhost on
for non
-MSIX virtio guests
\n"
1713 " use
'vhostfd=h' to connect to an already opened vhost net device
\n"
1714 " use
'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
1715 " use 'queues
=n
' to specify the number of queues to be created for multiqueue TAP\n"
1716 " use 'poll
-us
=n
' to speciy the maximum number of microseconds that could be\n"
1717 " spent on busy polling for vhost net\n"
1718 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
1719 " configure a host TAP network backend with ID 'str
' that is\n"
1720 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1721 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
1724 "-netdev l2tpv3
,id
=str
,src
=srcaddr
,dst
=dstaddr
[,srcport
=srcport
][,dstport
=dstport
]\n"
1725 " [,rxsession
=rxsession
],txsession
=txsession
[,ipv6
=on
/off
][,udp
=on
/off
]\n"
1726 " [,cookie64
=on
/off
][,counter
][,pincounter
][,txcookie
=txcookie
]\n"
1727 " [,rxcookie
=rxcookie
][,offset
=offset
]\n"
1728 " configure a network backend with ID
'str' connected to
\n"
1729 " an Ethernet over L2TPv3 pseudowire
.\n"
1730 " Linux kernel
3.3+ as well as most routers can talk
\n"
1731 " L2TPv3
. This transport allows connecting a VM to a VM
,\n"
1732 " VM to a router and even VM to Host
. It is a nearly
-universal
\n"
1733 " standard (RFC3391
). Note
- this implementation uses
static\n"
1734 " pre
-configured
tunnels (same as the Linux kernel
).\n"
1735 " use
'src=' to specify source address
\n"
1736 " use
'dst=' to specify destination address
\n"
1737 " use
'udp=on' to specify udp encapsulation
\n"
1738 " use
'srcport=' to specify source udp port
\n"
1739 " use
'dstport=' to specify destination udp port
\n"
1740 " use
'ipv6=on' to force v6
\n"
1741 " L2TPv3 uses cookies to prevent misconfiguration as
\n"
1742 " well as a weak security measure
\n"
1743 " use
'rxcookie=0x012345678' to specify a rxcookie
\n"
1744 " use
'txcookie=0x012345678' to specify a txcookie
\n"
1745 " use
'cookie64=on' to set cookie size to
64 bit
, otherwise
32\n"
1746 " use
'counter=off' to force a
'cut-down' L2TPv3 with no counter
\n"
1747 " use
'pincounter=on' to work around broken counter handling
in peer
\n"
1748 " use
'offset=X' to add an extra offset between header and data
\n"
1750 "-netdev socket
,id
=str
[,fd
=h
][,listen
=[host
]:port
][,connect
=host
:port
]\n"
1751 " configure a network backend to connect to another network
\n"
1752 " using a socket connection
\n"
1753 "-netdev socket
,id
=str
[,fd
=h
][,mcast
=maddr
:port
[,localaddr
=addr
]]\n"
1754 " configure a network backend to connect to a multicast maddr and port
\n"
1755 " use
'localaddr=addr' to specify the host address to send packets from
\n"
1756 "-netdev socket
,id
=str
[,fd
=h
][,udp
=host
:port
][,localaddr
=host
:port
]\n"
1757 " configure a network backend to connect to another network
\n"
1758 " using an UDP tunnel
\n"
1760 "-netdev vde
,id
=str
[,sock
=socketpath
][,port
=n
][,group
=groupname
][,mode
=octalmode
]\n"
1761 " configure a network backend to connect to port
'n' of a vde
switch\n"
1762 " running on host and listening
for incoming connections on
'socketpath'.\n"
1763 " Use group
'groupname' and mode
'octalmode' to change
default\n"
1764 " ownership and permissions
for communication port
.\n"
1766 #ifdef CONFIG_NETMAP
1767 "-netdev netmap
,id
=str
,ifname
=name
[,devname
=nmname
]\n"
1768 " attach to the existing netmap
-enabled network
interface 'name', or to a
\n"
1769 " VALE
port (created on the fly
) called
'name' ('nmname' is name of the
\n"
1770 " netmap device
, defaults to
'/dev/netmap')\n"
1772 "-netdev vhost
-user
,id
=str
,chardev
=dev
[,vhostforce
=on|off
]\n"
1773 " configure a vhost
-user network
, backed by a chardev
'dev'\n"
1774 "-netdev hubport
,id
=str
,hubid
=n
\n"
1775 " configure a hub port on QEMU VLAN
'n'\n", QEMU_ARCH_ALL)
1776 DEF("net
", HAS_ARG, QEMU_OPTION_net,
1777 "-net nic
[,vlan
=n
][,macaddr
=mac
][,model
=type
][,name
=str
][,addr
=str
][,vectors
=v
]\n"
1778 " old way to create a
new NIC and connect it to VLAN
'n'\n"
1779 " (use the
'-device devtype,netdev=str' option
if possible instead
)\n"
1780 "-net dump
[,vlan
=n
][,file
=f
][,len
=n
]\n"
1781 " dump traffic on vlan
'n' to file
'f' (max n bytes per packet
)\n"
1782 "-net none use it alone to have zero network devices
. If no
-net option
\n"
1783 " is provided
, the
default is
'-net nic -net user'\n"
1793 #ifdef CONFIG_NETMAP
1796 "socket
][,vlan
=n
][,option
][,option
][,...]\n"
1797 " old way to initialize a host network
interface\n"
1798 " (use the
-netdev option
if possible instead
)\n", QEMU_ARCH_ALL)
1800 @item -net nic[,vlan=@var{n}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}]
1802 Create a new Network Interface Card and connect it to VLAN @var{n} (@var{n}
1803 = 0 is the default). The NIC is an e1000 by default on the PC
1804 target. Optionally, the MAC address can be changed to @var{mac}, the
1805 device address set to @var{addr} (PCI cards only),
1806 and a @var{name} can be assigned for use in monitor commands.
1807 Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
1808 that the card should have; this option currently only affects virtio cards; set
1809 @var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
1810 NIC is created. QEMU can emulate several different models of network card.
1811 Valid values for @var{type} are
1812 @code{virtio}, @code{i82551}, @code{i82557b}, @code{i82559er},
1813 @code{ne2k_pci}, @code{ne2k_isa}, @code{pcnet}, @code{rtl8139},
1814 @code{e1000}, @code{smc91c111}, @code{lance} and @code{mcf_fec}.
1815 Not all devices are supported on all targets. Use @code{-net nic,model=help}
1816 for a list of available devices for your target.
1818 @item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
1820 @item -net user[,@var{option}][,@var{option}][,...]
1821 Use the user mode network stack which requires no administrator
1822 privilege to run. Valid options are:
1826 Connect user mode stack to VLAN @var{n} (@var{n} = 0 is the default).
1829 @itemx name=@var{name}
1830 Assign symbolic name for use in monitor commands.
1832 @option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must
1833 be enabled. If neither is specified both protocols are enabled.
1835 @item net=@var{addr}[/@var{mask}]
1836 Set IP network address the guest will see. Optionally specify the netmask,
1837 either in the form a.b.c.d or as number of valid top-most bits. Default is
1840 @item host=@var{addr}
1841 Specify the guest-visible address of the host. Default is the 2nd IP in the
1842 guest network, i.e. x.x.x.2.
1844 @item ipv6-net=@var{addr}[/@var{int}]
1845 Set IPv6 network address the guest will see (default is fec0::/64). The
1846 network prefix is given in the usual hexadecimal IPv6 address
1847 notation. The prefix size is optional, and is given as the number of
1848 valid top-most bits (default is 64).
1850 @item ipv6-host=@var{addr}
1851 Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
1852 the guest network, i.e. xxxx::2.
1854 @item restrict=on|off
1855 If this option is enabled, the guest will be isolated, i.e. it will not be
1856 able to contact the host and no guest IP packets will be routed over the host
1857 to the outside. This option does not affect any explicitly set forwarding rules.
1859 @item hostname=@var{name}
1860 Specifies the client hostname reported by the built-in DHCP server.
1862 @item dhcpstart=@var{addr}
1863 Specify the first of the 16 IPs the built-in DHCP server can assign. Default
1864 is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
1866 @item dns=@var{addr}
1867 Specify the guest-visible address of the virtual nameserver. The address must
1868 be different from the host address. Default is the 3rd IP in the guest network,
1871 @item ipv6-dns=@var{addr}
1872 Specify the guest-visible address of the IPv6 virtual nameserver. The address
1873 must be different from the host address. Default is the 3rd IP in the guest
1874 network, i.e. xxxx::3.
1876 @item dnssearch=@var{domain}
1877 Provides an entry for the domain-search list sent by the built-in
1878 DHCP server. More than one domain suffix can be transmitted by specifying
1879 this option multiple times. If supported, this will cause the guest to
1880 automatically try to append the given domain suffix(es) in case a domain name
1881 can not be resolved.
1885 qemu -net user,dnssearch=mgmt.example.org,dnssearch=example.org [...]
1888 @item tftp=@var{dir}
1889 When using the user mode network stack, activate a built-in TFTP
1890 server. The files in @var{dir} will be exposed as the root of a TFTP server.
1891 The TFTP client on the guest must be configured in binary mode (use the command
1892 @code{bin} of the Unix TFTP client).
1894 @item bootfile=@var{file}
1895 When using the user mode network stack, broadcast @var{file} as the BOOTP
1896 filename. In conjunction with @option{tftp}, this can be used to network boot
1897 a guest from a local directory.
1899 Example (using pxelinux):
1901 qemu-system-i386 -hda linux.img -boot n -net user,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
1904 @item smb=@var{dir}[,smbserver=@var{addr}]
1905 When using the user mode network stack, activate a built-in SMB
1906 server so that Windows OSes can access to the host files in @file{@var{dir}}
1907 transparently. The IP address of the SMB server can be set to @var{addr}. By
1908 default the 4th IP in the guest network is used, i.e. x.x.x.4.
1910 In the guest Windows OS, the line:
1914 must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
1915 or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
1917 Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
1919 Note that a SAMBA server must be installed on the host OS.
1920 QEMU was tested successfully with smbd versions from Red Hat 9,
1921 Fedora Core 3 and OpenSUSE 11.x.
1923 @item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
1924 Redirect incoming TCP or UDP connections to the host port @var{hostport} to
1925 the guest IP address @var{guestaddr} on guest port @var{guestport}. If
1926 @var{guestaddr} is not specified, its value is x.x.x.15 (default first address
1927 given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
1928 be bound to a specific host interface. If no connection type is set, TCP is
1929 used. This option can be given multiple times.
1931 For example, to redirect host X11 connection from screen 1 to guest
1932 screen 0, use the following:
1936 qemu-system-i386 -net user,hostfwd=tcp:127.0.0.1:6001-:6000 [...]
1937 # this host xterm should open in the guest X11 server
1941 To redirect telnet connections from host port 5555 to telnet port on
1942 the guest, use the following:
1946 qemu-system-i386 -net user,hostfwd=tcp::5555-:23 [...]
1947 telnet localhost 5555
1950 Then when you use on the host @code{telnet localhost 5555}, you
1951 connect to the guest telnet server.
1953 @item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
1954 @itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
1955 Forward guest TCP connections to the IP address @var{server} on port @var{port}
1956 to the character device @var{dev} or to a program executed by @var{cmd:command}
1957 which gets spawned for each connection. This option can be given multiple times.
1959 You can either use a chardev directly and have that one used throughout QEMU's
1960 lifetime, like in the following example:
1963 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
1964 # the guest accesses it
1965 qemu -net user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 [...]
1968 Or you can execute a command on every TCP connection established by the guest,
1969 so that QEMU behaves similar to an inetd process for that virtual server:
1972 # call "netcat
10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
1973 # and connect the TCP stream to its stdin/stdout
1974 qemu -net 'user,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
1979 Note: Legacy stand-alone options -tftp, -bootp, -smb and -redir are still
1980 processed and applied to -net user. Mixing them with the new configuration
1981 syntax gives undefined results. Their use for new applications is discouraged
1982 as they will be removed from future versions.
1984 @item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
1985 @itemx -net tap[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
1986 Connect the host TAP network interface @var{name} to VLAN @var{n}.
1988 Use the network script @var{file} to configure it and the network script
1989 @var{dfile} to deconfigure it. If @var{name} is not provided, the OS
1990 automatically provides one. The default network configure script is
1991 @file{/etc/qemu-ifup} and the default network deconfigure script is
1992 @file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no}
1993 to disable script execution.
1995 If running QEMU as an unprivileged user, use the network helper
1996 @var{helper} to configure the TAP interface and attach it to the bridge.
1997 The default network helper executable is @file{/path/to/qemu-bridge-helper}
1998 and the default bridge device is @file{br0}.
2000 @option{fd}=@var{h} can be used to specify the handle of an already
2001 opened host TAP interface.
2006 #launch a QEMU instance with the default network script
2007 qemu-system-i386 linux.img -net nic -net tap
2011 #launch a QEMU instance with two NICs, each one connected
2013 qemu-system-i386 linux.img \
2014 -net nic,vlan=0 -net tap,vlan=0,ifname=tap0 \
2015 -net nic,vlan=1 -net tap,vlan=1,ifname=tap1
2019 #launch a QEMU instance with the default network helper to
2020 #connect a TAP device to bridge br0
2021 qemu-system-i386 linux.img \
2022 -net nic -net tap,"helper
=/path
/to
/qemu
-bridge
-helper
"
2025 @item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}]
2026 @itemx -net bridge[,vlan=@var{n}][,name=@var{name}][,br=@var{bridge}][,helper=@var{helper}]
2027 Connect a host TAP network interface to a host bridge device.
2029 Use the network helper @var{helper} to configure the TAP interface and
2030 attach it to the bridge. The default network helper executable is
2031 @file{/path/to/qemu-bridge-helper} and the default bridge
2032 device is @file{br0}.
2037 #launch a QEMU instance with the default network helper to
2038 #connect a TAP device to bridge br0
2039 qemu-system-i386 linux.img -net bridge -net nic,model=virtio
2043 #launch a QEMU instance with the default network helper to
2044 #connect a TAP device to bridge qemubr0
2045 qemu-system-i386 linux.img -net bridge,br=qemubr0 -net nic,model=virtio
2048 @item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2049 @itemx -net socket[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}] [,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2051 Connect the VLAN @var{n} to a remote VLAN in another QEMU virtual
2052 machine using a TCP socket connection. If @option{listen} is
2053 specified, QEMU waits for incoming connections on @var{port}
2054 (@var{host} is optional). @option{connect} is used to connect to
2055 another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2056 specifies an already opened TCP socket.
2060 # launch a first QEMU instance
2061 qemu-system-i386 linux.img \
2062 -net nic,macaddr=52:54:00:12:34:56 \
2063 -net socket,listen=:1234
2064 # connect the VLAN 0 of this instance to the VLAN 0
2065 # of the first instance
2066 qemu-system-i386 linux.img \
2067 -net nic,macaddr=52:54:00:12:34:57 \
2068 -net socket,connect=127.0.0.1:1234
2071 @item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2072 @itemx -net socket[,vlan=@var{n}][,name=@var{name}][,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2074 Create a VLAN @var{n} shared with another QEMU virtual
2075 machines using a UDP multicast socket, effectively making a bus for
2076 every QEMU with same multicast address @var{maddr} and @var{port}.
2080 Several QEMU can be running on different hosts and share same bus (assuming
2081 correct multicast setup for these hosts).
2083 mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
2084 @url{http://user-mode-linux.sf.net}.
2086 Use @option{fd=h} to specify an already opened UDP multicast socket.
2091 # launch one QEMU instance
2092 qemu-system-i386 linux.img \
2093 -net nic,macaddr=52:54:00:12:34:56 \
2094 -net socket,mcast=230.0.0.1:1234
2095 # launch another QEMU instance on same "bus
"
2096 qemu-system-i386 linux.img \
2097 -net nic,macaddr=52:54:00:12:34:57 \
2098 -net socket,mcast=230.0.0.1:1234
2099 # launch yet another QEMU instance on same "bus
"
2100 qemu-system-i386 linux.img \
2101 -net nic,macaddr=52:54:00:12:34:58 \
2102 -net socket,mcast=230.0.0.1:1234
2105 Example (User Mode Linux compat.):
2107 # launch QEMU instance (note mcast address selected
2109 qemu-system-i386 linux.img \
2110 -net nic,macaddr=52:54:00:12:34:56 \
2111 -net socket,mcast=239.192.168.1:1102
2113 /path/to/linux ubd0=/path/to/root_fs eth0=mcast
2116 Example (send packets from host's 1.2.3.4):
2118 qemu-system-i386 linux.img \
2119 -net nic,macaddr=52:54:00:12:34:56 \
2120 -net socket,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2123 @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}]
2124 @itemx -net l2tpv3[,vlan=@var{n}][,name=@var{name}],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}]
2125 Connect VLAN @var{n} to L2TPv3 pseudowire. L2TPv3 (RFC3391) is a popular
2126 protocol to transport Ethernet (and other Layer 2) data frames between
2127 two systems. It is present in routers, firewalls and the Linux kernel
2128 (from version 3.3 onwards).
2130 This transport allows a VM to communicate to another VM, router or firewall directly.
2132 @item src=@var{srcaddr}
2133 source address (mandatory)
2134 @item dst=@var{dstaddr}
2135 destination address (mandatory)
2137 select udp encapsulation (default is ip).
2138 @item srcport=@var{srcport}
2140 @item dstport=@var{dstport}
2141 destination udp port.
2143 force v6, otherwise defaults to v4.
2144 @item rxcookie=@var{rxcookie}
2145 @itemx txcookie=@var{txcookie}
2146 Cookies are a weak form of security in the l2tpv3 specification.
2147 Their function is mostly to prevent misconfiguration. By default they are 32
2150 Set cookie size to 64 bit instead of the default 32
2152 Force a 'cut-down' L2TPv3 with no counter as in
2153 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2155 Work around broken counter handling in peer. This may also help on
2156 networks which have packet reorder.
2157 @item offset=@var{offset}
2158 Add an extra offset between header and data
2160 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan
2161 on the remote Linux host 1.2.3.4:
2163 # Setup tunnel on linux host using raw ip as encapsulation
2165 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \
2166 encap udp udp_sport 16384 udp_dport 16384
2167 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \
2168 0xFFFFFFFF peer_session_id 0xFFFFFFFF
2169 ifconfig vmtunnel0 mtu 1500
2170 ifconfig vmtunnel0 up
2171 brctl addif br-lan vmtunnel0
2175 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2177 qemu-system-i386 linux.img -net nic -net l2tpv3,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2182 @item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2183 @itemx -net vde[,vlan=@var{n}][,name=@var{name}][,sock=@var{socketpath}] [,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2184 Connect VLAN @var{n} to PORT @var{n} of a vde switch running on host and
2185 listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}
2186 and MODE @var{octalmode} to change default ownership and permissions for
2187 communication port. This option is only available if QEMU has been compiled
2188 with vde support enabled.
2193 vde_switch -F -sock /tmp/myswitch
2194 # launch QEMU instance
2195 qemu-system-i386 linux.img -net nic -net vde,sock=/tmp/myswitch
2198 @item -netdev hubport,id=@var{id},hubid=@var{hubid}
2200 Create a hub port on QEMU "vlan
" @var{hubid}.
2202 The hubport netdev lets you connect a NIC to a QEMU "vlan
" instead of a single
2203 netdev. @code{-net} and @code{-device} with parameter @option{vlan} create the
2204 required hub automatically.
2206 @item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
2208 Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
2209 be a unix domain socket backed one. The vhost-user uses a specifically defined
2210 protocol to pass vhost ioctl replacement messages to an application on the other
2211 end of the socket. On non-MSIX guests, the feature can be forced with
2212 @var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
2213 be created for multiqueue vhost-user.
2217 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
2218 -numa node,memdev=mem \
2219 -chardev socket,id=chr0,path=/path/to/socket \
2220 -netdev type=vhost-user,id=net0,chardev=chr0 \
2221 -device virtio-net-pci,netdev=net0
2224 @item -net dump[,vlan=@var{n}][,file=@var{file}][,len=@var{len}]
2225 Dump network traffic on VLAN @var{n} to file @var{file} (@file{qemu-vlan0.pcap} by default).
2226 At most @var{len} bytes (64k by default) per packet are stored. The file format is
2227 libpcap, so it can be analyzed with tools such as tcpdump or Wireshark.
2228 Note: For devices created with '-netdev', use '-object filter-dump,...' instead.
2231 Indicate that no network devices should be configured. It is used to
2232 override the default configuration (@option{-net nic -net user}) which
2233 is activated if no @option{-net} options are provided.
2241 DEFHEADING(Character device options)
2244 The general form of a character device option is:
2248 DEF("chardev
", HAS_ARG, QEMU_OPTION_chardev,
2250 "-chardev
null,id
=id
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2251 "-chardev socket
,id
=id
[,host
=host
],port
=port
[,to
=to
][,ipv4
][,ipv6
][,nodelay
][,reconnect
=seconds
]\n"
2252 " [,server
][,nowait
][,telnet
][,reconnect
=seconds
][,mux
=on|off
]\n"
2253 " [,logfile
=PATH
][,logappend
=on|off
][,tls
-creds
=ID
] (tcp
)\n"
2254 "-chardev socket
,id
=id
,path
=path
[,server
][,nowait
][,telnet
][,reconnect
=seconds
]\n"
2255 " [,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
] (unix
)\n"
2256 "-chardev udp
,id
=id
[,host
=host
],port
=port
[,localaddr
=localaddr
]\n"
2257 " [,localport
=localport
][,ipv4
][,ipv6
][,mux
=on|off
]\n"
2258 " [,logfile
=PATH
][,logappend
=on|off
]\n"
2259 "-chardev msmouse
,id
=id
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2260 "-chardev vc
,id
=id
[[,width
=width
][,height
=height
]][[,cols
=cols
][,rows
=rows
]]\n"
2261 " [,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2262 "-chardev ringbuf
,id
=id
[,size
=size
][,logfile
=PATH
][,logappend
=on|off
]\n"
2263 "-chardev file
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2264 "-chardev pipe
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2266 "-chardev console
,id
=id
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2267 "-chardev serial
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2269 "-chardev pty
,id
=id
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2270 "-chardev stdio
,id
=id
[,mux
=on|off
][,signal
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2272 #ifdef CONFIG_BRLAPI
2273 "-chardev braille
,id
=id
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2275 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
2276 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
2277 "-chardev serial
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2278 "-chardev tty
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2280 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
2281 "-chardev parallel
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2282 "-chardev parport
,id
=id
,path
=path
[,mux
=on|off
][,logfile
=PATH
][,logappend
=on|off
]\n"
2284 #if defined(CONFIG_SPICE)
2285 "-chardev spicevmc
,id
=id
,name
=name
[,debug
=debug
][,logfile
=PATH
][,logappend
=on|off
]\n"
2286 "-chardev spiceport
,id
=id
,name
=name
[,debug
=debug
][,logfile
=PATH
][,logappend
=on|off
]\n"
2292 @item -chardev @var{backend} ,id=@var{id} [,mux=on|off] [,@var{options}]
2313 The specific backend will determine the applicable options.
2315 Use "-chardev help
" to print all available chardev backend types.
2317 All devices must have an id, which can be any string up to 127 characters long.
2318 It is used to uniquely identify this device in other command line directives.
2320 A character device may be used in multiplexing mode by multiple front-ends.
2321 Specify @option{mux=on} to enable this mode.
2322 A multiplexer is a "1:N
" device, and here the "1" end is your specified chardev
2323 backend, and the "N
" end is the various parts of QEMU that can talk to a chardev.
2324 If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will
2325 create a multiplexer with your specified ID, and you can then configure multiple
2326 front ends to use that chardev ID for their input/output. Up to four different
2327 front ends can be connected to a single multiplexed chardev. (Without
2328 multiplexing enabled, a chardev can only be used by a single front end.)
2329 For instance you could use this to allow a single stdio chardev to be used by
2330 two serial ports and the QEMU monitor:
2333 -chardev stdio,mux=on,id=char0 \
2334 -mon chardev=char0,mode=readline \
2335 -serial chardev:char0 \
2336 -serial chardev:char0
2339 You can have more than one multiplexer in a system configuration; for instance
2340 you could have a TCP port multiplexed between UART 0 and UART 1, and stdio
2341 multiplexed between the QEMU monitor and a parallel port:
2344 -chardev stdio,mux=on,id=char0 \
2345 -mon chardev=char0,mode=readline \
2346 -parallel chardev:char0 \
2347 -chardev tcp,...,mux=on,id=char1 \
2348 -serial chardev:char1 \
2349 -serial chardev:char1
2352 When you're using a multiplexed character device, some escape sequences are
2353 interpreted in the input. @xref{mux_keys, Keys in the character backend
2356 Note that some other command line options may implicitly create multiplexed
2357 character backends; for instance @option{-serial mon:stdio} creates a
2358 multiplexed stdio backend connected to the serial port and the QEMU monitor,
2359 and @option{-nographic} also multiplexes the console and the monitor to
2362 There is currently no support for multiplexing in the other direction
2363 (where a single QEMU front end takes input and output from multiple chardevs).
2365 Every backend supports the @option{logfile} option, which supplies the path
2366 to a file to record all data transmitted via the backend. The @option{logappend}
2367 option controls whether the log file will be truncated or appended to when
2370 Further options to each backend are described below.
2372 @item -chardev null ,id=@var{id}
2373 A void device. This device will not emit any data, and will drop any data it
2374 receives. The null backend does not take any options.
2376 @item -chardev socket ,id=@var{id} [@var{TCP options} or @var{unix options}] [,server] [,nowait] [,telnet] [,reconnect=@var{seconds}] [,tls-creds=@var{id}]
2378 Create a two-way stream socket, which can be either a TCP or a unix socket. A
2379 unix socket will be created if @option{path} is specified. Behaviour is
2380 undefined if TCP options are specified for a unix socket.
2382 @option{server} specifies that the socket shall be a listening socket.
2384 @option{nowait} specifies that QEMU should not block waiting for a client to
2385 connect to a listening socket.
2387 @option{telnet} specifies that traffic on the socket should interpret telnet
2390 @option{reconnect} sets the timeout for reconnecting on non-server sockets when
2391 the remote end goes away. qemu will delay this many seconds and then attempt
2392 to reconnect. Zero disables reconnecting, and is the default.
2394 @option{tls-creds} requests enablement of the TLS protocol for encryption,
2395 and specifies the id of the TLS credentials to use for the handshake. The
2396 credentials must be previously created with the @option{-object tls-creds}
2399 TCP and unix socket options are given below:
2403 @item TCP options: port=@var{port} [,host=@var{host}] [,to=@var{to}] [,ipv4] [,ipv6] [,nodelay]
2405 @option{host} for a listening socket specifies the local address to be bound.
2406 For a connecting socket species the remote host to connect to. @option{host} is
2407 optional for listening sockets. If not specified it defaults to @code{0.0.0.0}.
2409 @option{port} for a listening socket specifies the local port to be bound. For a
2410 connecting socket specifies the port on the remote host to connect to.
2411 @option{port} can be given as either a port number or a service name.
2412 @option{port} is required.
2414 @option{to} is only relevant to listening sockets. If it is specified, and
2415 @option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up
2416 to and including @option{to} until it succeeds. @option{to} must be specified
2419 @option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2420 If neither is specified the socket may use either protocol.
2422 @option{nodelay} disables the Nagle algorithm.
2424 @item unix options: path=@var{path}
2426 @option{path} specifies the local path of the unix socket. @option{path} is
2431 @item -chardev udp ,id=@var{id} [,host=@var{host}] ,port=@var{port} [,localaddr=@var{localaddr}] [,localport=@var{localport}] [,ipv4] [,ipv6]
2433 Sends all traffic from the guest to a remote host over UDP.
2435 @option{host} specifies the remote host to connect to. If not specified it
2436 defaults to @code{localhost}.
2438 @option{port} specifies the port on the remote host to connect to. @option{port}
2441 @option{localaddr} specifies the local address to bind to. If not specified it
2442 defaults to @code{0.0.0.0}.
2444 @option{localport} specifies the local port to bind to. If not specified any
2445 available local port will be used.
2447 @option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2448 If neither is specified the device may use either protocol.
2450 @item -chardev msmouse ,id=@var{id}
2452 Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not
2455 @item -chardev vc ,id=@var{id} [[,width=@var{width}] [,height=@var{height}]] [[,cols=@var{cols}] [,rows=@var{rows}]]
2457 Connect to a QEMU text console. @option{vc} may optionally be given a specific
2460 @option{width} and @option{height} specify the width and height respectively of
2461 the console, in pixels.
2463 @option{cols} and @option{rows} specify that the console be sized to fit a text
2464 console with the given dimensions.
2466 @item -chardev ringbuf ,id=@var{id} [,size=@var{size}]
2468 Create a ring buffer with fixed size @option{size}.
2469 @var{size} must be a power of two and defaults to @code{64K}.
2471 @item -chardev file ,id=@var{id} ,path=@var{path}
2473 Log all traffic received from the guest to a file.
2475 @option{path} specifies the path of the file to be opened. This file will be
2476 created if it does not already exist, and overwritten if it does. @option{path}
2479 @item -chardev pipe ,id=@var{id} ,path=@var{path}
2481 Create a two-way connection to the guest. The behaviour differs slightly between
2482 Windows hosts and other hosts:
2484 On Windows, a single duplex pipe will be created at
2485 @file{\\.pipe\@option{path}}.
2487 On other hosts, 2 pipes will be created called @file{@option{path}.in} and
2488 @file{@option{path}.out}. Data written to @file{@option{path}.in} will be
2489 received by the guest. Data written by the guest can be read from
2490 @file{@option{path}.out}. QEMU will not create these fifos, and requires them to
2493 @option{path} forms part of the pipe path as described above. @option{path} is
2496 @item -chardev console ,id=@var{id}
2498 Send traffic from the guest to QEMU's standard output. @option{console} does not
2501 @option{console} is only available on Windows hosts.
2503 @item -chardev serial ,id=@var{id} ,path=@option{path}
2505 Send traffic from the guest to a serial device on the host.
2507 On Unix hosts serial will actually accept any tty device,
2508 not only serial lines.
2510 @option{path} specifies the name of the serial device to open.
2512 @item -chardev pty ,id=@var{id}
2514 Create a new pseudo-terminal on the host and connect to it. @option{pty} does
2515 not take any options.
2517 @option{pty} is not available on Windows hosts.
2519 @item -chardev stdio ,id=@var{id} [,signal=on|off]
2520 Connect to standard input and standard output of the QEMU process.
2522 @option{signal} controls if signals are enabled on the terminal, that includes
2523 exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
2524 default, use @option{signal=off} to disable it.
2526 @item -chardev braille ,id=@var{id}
2528 Connect to a local BrlAPI server. @option{braille} does not take any options.
2530 @item -chardev tty ,id=@var{id} ,path=@var{path}
2532 @option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
2533 DragonFlyBSD hosts. It is an alias for @option{serial}.
2535 @option{path} specifies the path to the tty. @option{path} is required.
2537 @item -chardev parallel ,id=@var{id} ,path=@var{path}
2538 @itemx -chardev parport ,id=@var{id} ,path=@var{path}
2540 @option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
2542 Connect to a local parallel port.
2544 @option{path} specifies the path to the parallel port device. @option{path} is
2547 @item -chardev spicevmc ,id=@var{id} ,debug=@var{debug}, name=@var{name}
2549 @option{spicevmc} is only available when spice support is built in.
2551 @option{debug} debug level for spicevmc
2553 @option{name} name of spice channel to connect to
2555 Connect to a spice virtual machine channel, such as vdiport.
2557 @item -chardev spiceport ,id=@var{id} ,debug=@var{debug}, name=@var{name}
2559 @option{spiceport} is only available when spice support is built in.
2561 @option{debug} debug level for spicevmc
2563 @option{name} name of spice port to connect to
2565 Connect to a spice port, allowing a Spice client to handle the traffic
2566 identified by a name (preferably a fqdn).
2574 DEFHEADING(Device URL Syntax)
2577 In addition to using normal file images for the emulated storage devices,
2578 QEMU can also use networked resources such as iSCSI devices. These are
2579 specified using a special URL syntax.
2583 iSCSI support allows QEMU to access iSCSI resources directly and use as
2584 images for the guest storage. Both disk and cdrom images are supported.
2586 Syntax for specifying iSCSI LUNs is
2587 ``iscsi://<target-ip>[:<port>]/<target-iqn>/<lun>''
2589 By default qemu will use the iSCSI initiator-name
2590 'iqn.2008-11.org.linux-kvm[:<name>]' but this can also be set from the command
2591 line or a configuration file.
2593 Since version Qemu 2.4 it is possible to specify a iSCSI request timeout to detect
2594 stalled requests and force a reestablishment of the session. The timeout
2595 is specified in seconds. The default is 0 which means no timeout. Libiscsi
2596 1.15.0 or greater is required for this feature.
2598 Example (without authentication):
2600 qemu-system-i386 -iscsi initiator-name=iqn.2001-04.com.example:my-initiator \
2601 -cdrom iscsi://192.0.2.1/iqn.2001-04.com.example/2 \
2602 -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1
2605 Example (CHAP username/password via URL):
2607 qemu-system-i386 -drive file=iscsi://user%password@@192.0.2.1/iqn.2001-04.com.example/1
2610 Example (CHAP username/password via environment variables):
2612 LIBISCSI_CHAP_USERNAME="user
" \
2613 LIBISCSI_CHAP_PASSWORD="password
" \
2614 qemu-system-i386 -drive file=iscsi://192.0.2.1/iqn.2001-04.com.example/1
2617 iSCSI support is an optional feature of QEMU and only available when
2618 compiled and linked against libiscsi.
2620 DEF("iscsi
", HAS_ARG, QEMU_OPTION_iscsi,
2621 "-iscsi
[user
=user
][,password
=password
]\n"
2622 " [,header
-digest
=CRC32C|CR32C
-NONE|NONE
-CRC32C|NONE
\n"
2623 " [,initiator
-name
=initiator
-iqn
][,id
=target
-iqn
]\n"
2624 " [,timeout
=timeout
]\n"
2625 " iSCSI session parameters
\n", QEMU_ARCH_ALL)
2628 iSCSI parameters such as username and password can also be specified via
2629 a configuration file. See qemu-doc for more information and examples.
2632 QEMU supports NBD (Network Block Devices) both using TCP protocol as well
2633 as Unix Domain Sockets.
2635 Syntax for specifying a NBD device using TCP
2636 ``nbd:<server-ip>:<port>[:exportname=<export>]''
2638 Syntax for specifying a NBD device using Unix Domain Sockets
2639 ``nbd:unix:<domain-socket>[:exportname=<export>]''
2644 qemu-system-i386 --drive file=nbd:192.0.2.1:30000
2647 Example for Unix Domain Sockets
2649 qemu-system-i386 --drive file=nbd:unix:/tmp/nbd-socket
2653 QEMU supports SSH (Secure Shell) access to remote disks.
2657 qemu-system-i386 -drive file=ssh://user@@host/path/to/disk.img
2658 qemu-system-i386 -drive file.driver=ssh,file.user=user,file.host=host,file.port=22,file.path=/path/to/disk.img
2661 Currently authentication must be done using ssh-agent. Other
2662 authentication methods may be supported in future.
2665 Sheepdog is a distributed storage system for QEMU.
2666 QEMU supports using either local sheepdog devices or remote networked
2669 Syntax for specifying a sheepdog device
2671 sheepdog[+tcp|+unix]://[host:port]/vdiname[?socket=path][#snapid|#tag]
2676 qemu-system-i386 --drive file=sheepdog://192.0.2.1:30000/MyVirtualMachine
2679 See also @url{https://sheepdog.github.io/sheepdog/}.
2682 GlusterFS is a user space distributed file system.
2683 QEMU supports the use of GlusterFS volumes for hosting VM disk images using
2684 TCP, Unix Domain Sockets and RDMA transport protocols.
2686 Syntax for specifying a VM disk image on GlusterFS volume is
2690 gluster[+type]://[host[:port]]/volume/path[?socket=...][,debug=N][,logfile=...]
2693 'json:@{"driver
":"qcow2
","file
":@{"driver
":"gluster
","volume
":"testvol
","path
":"a
.img
","debug
":N,"logfile
":"...",
2694 @ "server
":[@{"type
":"tcp
","host
":"...","port
":"..."@},
2695 @ @{"type
":"unix
","socket
":"..."@}]@}@}'
2702 qemu-system-x86_64 --drive file=gluster://192.0.2.1/testvol/a.img,
2703 @ file.debug=9,file.logfile=/var/log/qemu-gluster.log
2706 qemu-system-x86_64 'json:@{"driver
":"qcow2
",
2707 @ "file
":@{"driver
":"gluster
",
2708 @ "volume
":"testvol
","path
":"a
.img
",
2709 @ "debug
":9,"logfile
":"/var/log
/qemu
-gluster
.log
",
2710 @ "server
":[@{"type
":"tcp
","host
":"1.2.3.4","port
":24007@},
2711 @ @{"type
":"unix
","socket
":"/var/run
/glusterd
.socket
"@}]@}@}'
2712 qemu-system-x86_64 -drive driver=qcow2,file.driver=gluster,file.volume=testvol,file.path=/path/a.img,
2713 @ file.debug=9,file.logfile=/var/log/qemu-gluster.log,
2714 @ file.server.0.type=tcp,file.server.0.host=1.2.3.4,file.server.0.port=24007,
2715 @ file.server.1.type=unix,file.server.1.socket=/var/run/glusterd.socket
2718 See also @url{http://www.gluster.org}.
2720 @item HTTP/HTTPS/FTP/FTPS
2721 QEMU supports read-only access to files accessed over http(s) and ftp(s).
2723 Syntax using a single filename:
2725 <protocol>://[<username>[:<password>]@@]<host>/<path>
2731 'http', 'https', 'ftp', or 'ftps'.
2734 Optional username for authentication to the remote server.
2737 Optional password for authentication to the remote server.
2740 Address of the remote server.
2743 Path on the remote server, including any query string.
2746 The following options are also supported:
2749 The full URL when passing options to the driver explicitly.
2752 The amount of data to read ahead with each range request to the remote server.
2753 This value may optionally have the suffix 'T', 'G', 'M', 'K', 'k' or 'b'. If it
2754 does not have a suffix, it will be assumed to be in bytes. The value must be a
2755 multiple of 512 bytes. It defaults to 256k.
2758 Whether to verify the remote server's certificate when connecting over SSL. It
2759 can have the value 'on' or 'off'. It defaults to 'on'.
2762 Send this cookie (it can also be a list of cookies separated by ';') with
2763 each outgoing request. Only supported when using protocols such as HTTP
2764 which support cookies, otherwise ignored.
2767 Set the timeout in seconds of the CURL connection. This timeout is the time
2768 that CURL waits for a response from the remote server to get the size of the
2769 image to be downloaded. If not set, the default timeout of 5 seconds is used.
2772 Note that when passing options to qemu explicitly, @option{driver} is the value
2775 Example: boot from a remote Fedora 20 live ISO image
2777 qemu-system-x86_64 --drive media=cdrom,file=http://dl.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly
2779 qemu-system-x86_64 --drive media=cdrom,file.driver=http,file.url=http://dl.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso,readonly
2782 Example: boot from a remote Fedora 20 cloud image using a local overlay for
2783 writes, copy-on-read, and a readahead of 64k
2785 qemu-img create -f qcow2 -o backing_file='json:@{"file
.driver
":"http
",, "file
.url
":"https
://dl.fedoraproject.org/pub/fedora/linux/releases/20/Images/x86_64/Fedora-x86_64-20-20131211.1-sda.qcow2",, "file.readahead":"64k"@}' /tmp/Fedora-x86_64-20-20131211.1-sda.qcow2
2787 qemu
-system
-x86_64
-drive file
=/tmp
/Fedora
-x86_64
-20-20131211.1-sda
.qcow2
,copy
-on
-read
=on
2790 Example
: boot from an image stored on a VMware vSphere server with a self
-signed
2791 certificate
using a local overlay
for writes
, a readahead of
64k and a timeout
2794 qemu
-img create
-f qcow2
-o backing_file
='json:@{"file.driver":"https",, "file.url":"https://user:password@@vsphere.example.com/folder/test/test-flat.vmdk?dcPath=Datacenter&dsName=datastore1",, "file.sslverify":"off",, "file.readahead":"64k",, "file.timeout":10@}' /tmp
/test
.qcow2
2796 qemu
-system
-x86_64
-drive file
=/tmp
/test
.qcow2
2804 DEFHEADING(Bluetooth(R
) options
)
2809 DEF("bt", HAS_ARG
, QEMU_OPTION_bt
, \
2810 "-bt hci,null dumb bluetooth HCI - doesn't respond to commands\n" \
2811 "-bt hci,host[:id]\n" \
2812 " use host's HCI with the given name\n" \
2813 "-bt hci[,vlan=n]\n" \
2814 " emulate a standard HCI in virtual scatternet 'n'\n" \
2815 "-bt vhci[,vlan=n]\n" \
2816 " add host computer to virtual scatternet 'n' using VHCI\n" \
2817 "-bt device:dev[,vlan=n]\n" \
2818 " emulate a bluetooth device 'dev' in scatternet 'n'\n",
2823 Defines the
function of the corresponding Bluetooth HCI
. -bt options
2824 are matched with the HCIs present
in the chosen machine type
. For
2825 example when emulating a machine with only one HCI built into it
, only
2826 the first @code
{-bt hci
[...]} option is valid and defines the HCI
's
2827 logic. The Transport Layer is decided by the machine type. Currently
2828 the machines @code{n800} and @code{n810} have one HCI and all other
2832 The following three types are recognized:
2836 (default) The corresponding Bluetooth HCI assumes no internal logic
2837 and will not respond to any HCI commands or emit events.
2839 @item -bt hci,host[:@var{id}]
2840 (@code{bluez} only) The corresponding HCI passes commands / events
2841 to / from the physical HCI identified by the name @var{id} (default:
2842 @code{hci0}) on the computer running QEMU. Only available on @code{bluez}
2843 capable systems like Linux.
2845 @item -bt hci[,vlan=@var{n}]
2846 Add a virtual, standard HCI that will participate in the Bluetooth
2847 scatternet @var{n} (default @code{0}). Similarly to @option{-net}
2848 VLANs, devices inside a bluetooth network @var{n} can only communicate
2849 with other devices in the same network (scatternet).
2852 @item -bt vhci[,vlan=@var{n}]
2853 (Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached
2854 to the host bluetooth stack instead of to the emulated target. This
2855 allows the host and target machines to participate in a common scatternet
2856 and communicate. Requires the Linux @code{vhci} driver installed. Can
2857 be used as following:
2860 qemu-system-i386 [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5
2863 @item -bt device:@var{dev}[,vlan=@var{n}]
2864 Emulate a bluetooth device @var{dev} and place it in network @var{n}
2865 (default @code{0}). QEMU can only emulate one type of bluetooth devices
2870 Virtual wireless keyboard implementing the HIDP bluetooth profile.
2880 DEFHEADING(TPM device options)
2882 DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
2883 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
2884 " use path to provide path to a character device; default is /dev/tpm0\n"
2885 " use cancel-path to provide path to TPM's cancel sysfs entry
; if\n"
2886 " not provided it will be searched
for in /sys
/class/misc
/tpm?
/device
\n",
2890 The general form of a TPM device option is:
2893 @item -tpmdev @var{backend} ,id=@var{id} [,@var{options}]
2895 Backend type must be:
2896 @option{passthrough}.
2898 The specific backend type will determine the applicable options.
2899 The @code{-tpmdev} option creates the TPM backend and requires a
2900 @code{-device} option that specifies the TPM frontend interface model.
2902 Options to each backend are described below.
2904 Use 'help' to print all available TPM backend types.
2909 @item -tpmdev passthrough, id=@var{id}, path=@var{path}, cancel-path=@var{cancel-path}
2911 (Linux-host only) Enable access to the host's TPM using the passthrough
2914 @option{path} specifies the path to the host's TPM device, i.e., on
2915 a Linux host this would be @code{/dev/tpm0}.
2916 @option{path} is optional and by default @code{/dev/tpm0} is used.
2918 @option{cancel-path} specifies the path to the host TPM device's sysfs
2919 entry allowing for cancellation of an ongoing TPM command.
2920 @option{cancel-path} is optional and by default QEMU will search for the
2923 Some notes about using the host's TPM with the passthrough driver:
2925 The TPM device accessed by the passthrough driver must not be
2926 used by any other application on the host.
2928 Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
2929 the VM's firmware (BIOS/UEFI) will not be able to initialize the
2930 TPM again and may therefore not show a TPM-specific menu that would
2931 otherwise allow the user to configure the TPM, e.g., allow the user to
2932 enable/disable or activate/deactivate the TPM.
2933 Further, if TPM ownership is released from within a VM then the host's TPM
2934 will get disabled and deactivated. To enable and activate the
2935 TPM again afterwards, the host has to be rebooted and the user is
2936 required to enter the firmware's menu to enable and activate the TPM.
2937 If the TPM is left disabled and/or deactivated most TPM commands will fail.
2939 To create a passthrough TPM use the following two options:
2941 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
2943 Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
2944 @code{tpmdev=tpm0} in the device option.
2954 DEFHEADING(Linux/Multiboot boot specific)
2957 When using these options, you can use a given Linux or Multiboot
2958 kernel without installing it in the disk image. It can be useful
2959 for easier testing of various kernels.
2964 DEF("kernel
", HAS_ARG, QEMU_OPTION_kernel, \
2965 "-kernel bzImage use
'bzImage' as kernel image
\n", QEMU_ARCH_ALL)
2967 @item -kernel @var{bzImage}
2969 Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
2970 or in multiboot format.
2973 DEF("append
", HAS_ARG, QEMU_OPTION_append, \
2974 "-append cmdline use
'cmdline' as kernel command line
\n", QEMU_ARCH_ALL)
2976 @item -append @var{cmdline}
2978 Use @var{cmdline} as kernel command line
2981 DEF("initrd
", HAS_ARG, QEMU_OPTION_initrd, \
2982 "-initrd file use
'file' as initial ram disk
\n", QEMU_ARCH_ALL)
2984 @item -initrd @var{file}
2986 Use @var{file} as initial ram disk.
2988 @item -initrd "@
var{file1
} arg
=foo
,@
var{file2
}"
2990 This syntax is only available with multiboot.
2992 Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
2996 DEF("dtb
", HAS_ARG, QEMU_OPTION_dtb, \
2997 "-dtb file use
'file' as device tree image
\n", QEMU_ARCH_ALL)
2999 @item -dtb @var{file}
3001 Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
3010 DEFHEADING(Debug/Expert options)
3015 DEF("fw_cfg
", HAS_ARG, QEMU_OPTION_fwcfg,
3016 "-fw_cfg
[name
=]<name
>,file
=<file
>\n"
3017 " add named fw_cfg entry with contents from file
\n"
3018 "-fw_cfg
[name
=]<name
>,string
=<str
>\n"
3019 " add named fw_cfg entry with contents from string
\n",
3023 @item -fw_cfg [name=]@var{name},file=@var{file}
3025 Add named fw_cfg entry with contents from file @var{file}.
3027 @item -fw_cfg [name=]@var{name},string=@var{str}
3028 Add named fw_cfg entry with contents from string @var{str}.
3030 The terminating NUL character of the contents of @var{str} will not be
3031 included as part of the fw_cfg item data. To insert contents with
3032 embedded NUL characters, you have to use the @var{file} parameter.
3034 The fw_cfg entries are passed by QEMU through to the guest.
3038 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3040 creates an fw_cfg entry named opt/com.mycompany/blob with contents
3045 DEF("serial
", HAS_ARG, QEMU_OPTION_serial, \
3046 "-serial dev redirect the serial port to char device
'dev'\n",
3049 @item -serial @var{dev}
3051 Redirect the virtual serial port to host character device
3052 @var{dev}. The default device is @code{vc} in graphical mode and
3053 @code{stdio} in non graphical mode.
3055 This option can be used several times to simulate up to 4 serial
3058 Use @code{-serial none} to disable all serial ports.
3060 Available character devices are:
3062 @item vc[:@var{W}x@var{H}]
3063 Virtual console. Optionally, a width and height can be given in pixel with
3067 It is also possible to specify width or height in characters:
3072 [Linux only] Pseudo TTY (a new PTY is automatically allocated)
3074 No device is allocated.
3077 @item chardev:@var{id}
3078 Use a named character device defined with the @code{-chardev} option.
3080 [Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3081 parameters are set according to the emulated ones.
3082 @item /dev/parport@var{N}
3083 [Linux only, parallel port only] Use host parallel port
3084 @var{N}. Currently SPP and EPP parallel port features can be used.
3085 @item file:@var{filename}
3086 Write output to @var{filename}. No character can be read.
3088 [Unix only] standard input/output
3089 @item pipe:@var{filename}
3090 name pipe @var{filename}
3092 [Windows only] Use host serial port @var{n}
3093 @item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3094 This implements UDP Net Console.
3095 When @var{remote_host} or @var{src_ip} are not specified
3096 they default to @code{0.0.0.0}.
3097 When not using a specified @var{src_port} a random port is automatically chosen.
3099 If you just want a simple readonly console you can use @code{netcat} or
3100 @code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3101 @code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3102 will appear in the netconsole session.
3104 If you plan to send characters back via netconsole or you want to stop
3105 and start QEMU a lot of times, you should have QEMU use the same
3106 source port each time by using something like @code{-serial
3107 udp::4555@@:4556} to QEMU. Another approach is to use a patched
3108 version of netcat which can listen to a TCP port and send and receive
3109 characters via udp. If you have a patched version of netcat which
3110 activates telnet remote echo and single char transfer, then you can
3111 use the following options to set up a netcat redirector to allow
3112 telnet on port 5555 to access the QEMU port.
3115 -serial udp::4555@@:4556
3116 @item netcat options:
3117 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3118 @item telnet options:
3122 @item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3123 The TCP Net Console has two modes of operation. It can send the serial
3124 I/O to a location or wait for a connection from a location. By default
3125 the TCP Net Console is sent to @var{host} at the @var{port}. If you use
3126 the @var{server} option QEMU will wait for a client socket application
3127 to connect to the port before continuing, unless the @code{nowait}
3128 option was specified. The @code{nodelay} option disables the Nagle buffering
3129 algorithm. The @code{reconnect} option only applies if @var{noserver} is
3130 set, if the connection goes down it will attempt to reconnect at the
3131 given interval. If @var{host} is omitted, 0.0.0.0 is assumed. Only
3132 one TCP connection at a time is accepted. You can use @code{telnet} to
3133 connect to the corresponding character device.
3135 @item Example to send tcp console to 192.168.0.2 port 4444
3136 -serial tcp:192.168.0.2:4444
3137 @item Example to listen and wait on port 4444 for connection
3138 -serial tcp::4444,server
3139 @item Example to not wait and listen on ip 192.168.0.100 port 4444
3140 -serial tcp:192.168.0.100:4444,server,nowait
3143 @item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3144 The telnet protocol is used instead of raw tcp sockets. The options
3145 work the same as if you had specified @code{-serial tcp}. The
3146 difference is that the port acts like a telnet server or client using
3147 telnet option negotiation. This will also allow you to send the
3148 MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3149 sequence. Typically in unix telnet you do it with Control-] and then
3150 type "send
break" followed by pressing the enter key.
3152 @item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3153 A unix domain socket is used instead of a tcp socket. The option works the
3154 same as if you had specified @code{-serial tcp} except the unix domain socket
3155 @var{path} is used for connections.
3157 @item mon:@var{dev_string}
3158 This is a special option to allow the monitor to be multiplexed onto
3159 another serial port. The monitor is accessed with key sequence of
3160 @key{Control-a} and then pressing @key{c}.
3161 @var{dev_string} should be any one of the serial devices specified
3162 above. An example to multiplex the monitor onto a telnet server
3163 listening on port 4444 would be:
3165 @item -serial mon:telnet::4444,server,nowait
3167 When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3168 QEMU any more but will be passed to the guest instead.
3171 Braille device. This will use BrlAPI to display the braille output on a real
3175 Three button serial mouse. Configure the guest to use Microsoft protocol.
3179 DEF("parallel
", HAS_ARG, QEMU_OPTION_parallel, \
3180 "-parallel dev redirect the parallel port to char device
'dev'\n",
3183 @item -parallel @var{dev}
3185 Redirect the virtual parallel port to host device @var{dev} (same
3186 devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3187 be used to use hardware devices connected on the corresponding host
3190 This option can be used several times to simulate up to 3 parallel
3193 Use @code{-parallel none} to disable all parallel ports.
3196 DEF("monitor
", HAS_ARG, QEMU_OPTION_monitor, \
3197 "-monitor dev redirect the monitor to char device
'dev'\n",
3200 @item -monitor @var{dev}
3202 Redirect the monitor to host device @var{dev} (same devices as the
3204 The default device is @code{vc} in graphical mode and @code{stdio} in
3206 Use @code{-monitor none} to disable the default monitor.
3208 DEF("qmp
", HAS_ARG, QEMU_OPTION_qmp, \
3209 "-qmp dev like
-monitor but opens
in 'control' mode
\n",
3212 @item -qmp @var{dev}
3214 Like -monitor but opens in 'control' mode.
3216 DEF("qmp
-pretty
", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3217 "-qmp
-pretty dev like
-qmp but uses pretty JSON formatting
\n",
3220 @item -qmp-pretty @var{dev}
3222 Like -qmp but uses pretty JSON formatting.
3225 DEF("mon
", HAS_ARG, QEMU_OPTION_mon, \
3226 "-mon
[chardev
=]name
[,mode
=readline|control
]\n", QEMU_ARCH_ALL)
3228 @item -mon [chardev=]name[,mode=readline|control]
3230 Setup monitor on chardev @var{name}.
3233 DEF("debugcon
", HAS_ARG, QEMU_OPTION_debugcon, \
3234 "-debugcon dev redirect the debug console to char device
'dev'\n",
3237 @item -debugcon @var{dev}
3239 Redirect the debug console to host device @var{dev} (same devices as the
3240 serial port). The debug console is an I/O port which is typically port
3241 0xe9; writing to that I/O port sends output to this device.
3242 The default device is @code{vc} in graphical mode and @code{stdio} in
3246 DEF("pidfile
", HAS_ARG, QEMU_OPTION_pidfile, \
3247 "-pidfile file write PID to
'file'\n", QEMU_ARCH_ALL)
3249 @item -pidfile @var{file}
3251 Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3255 DEF("singlestep
", 0, QEMU_OPTION_singlestep, \
3256 "-singlestep always run
in singlestep mode
\n", QEMU_ARCH_ALL)
3260 Run the emulation in single step mode.
3263 DEF("S
", 0, QEMU_OPTION_S, \
3264 "-S freeze CPU at
startup (use
'c' to start execution
)\n",
3269 Do not start CPU at startup (you must type 'c' in the monitor).
3272 DEF("realtime
", HAS_ARG, QEMU_OPTION_realtime,
3273 "-realtime
[mlock
=on|off
]\n"
3274 " run qemu with realtime features
\n"
3275 " mlock
=on|off controls mlock
support (default: on
)\n",
3278 @item -realtime mlock=on|off
3280 Run qemu with realtime features.
3281 mlocking qemu and guest memory can be enabled via @option{mlock=on}
3282 (enabled by default).
3285 DEF("gdb
", HAS_ARG, QEMU_OPTION_gdb, \
3286 "-gdb dev wait
for gdb connection on
'dev'\n", QEMU_ARCH_ALL)
3288 @item -gdb @var{dev}
3290 Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3291 connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3292 stdio are reasonable use case. The latter is allowing to start QEMU from
3293 within gdb and establish the connection via a pipe:
3295 (gdb) target remote | exec qemu-system-i386 -gdb stdio ...
3299 DEF("s
", 0, QEMU_OPTION_s, \
3300 "-s shorthand
for -gdb tcp
::" DEFAULT_GDBSTUB_PORT "\n",
3305 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3306 (@pxref{gdb_usage}).
3309 DEF("d
", HAS_ARG, QEMU_OPTION_d, \
3310 "-d item1
,... enable logging of specified
items (use
'-d help' for a list of log items
)\n",
3313 @item -d @var{item1}[,...]
3315 Enable logging of specified items. Use '-d help' for a list of log items.
3318 DEF("D
", HAS_ARG, QEMU_OPTION_D, \
3319 "-D logfile output log to
logfile (default stderr
)\n",
3322 @item -D @var{logfile}
3324 Output log in @var{logfile} instead of to stderr
3327 DEF("dfilter
", HAS_ARG, QEMU_OPTION_DFILTER, \
3328 "-dfilter range
,.. filter debug output to range of
addresses (useful
for -d cpu
,exec
,etc
..)\n",
3331 @item -dfilter @var{range1}[,...]
3333 Filter debug output to that relevant to a range of target addresses. The filter
3334 spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3335 @var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3336 addresses and sizes required. For example:
3338 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3340 Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3341 the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3342 block starting at 0xffffffc00005f000.
3345 DEF("L
", HAS_ARG, QEMU_OPTION_L, \
3346 "-L path set the directory
for the BIOS
, VGA BIOS and keymaps
\n",
3351 Set the directory for the BIOS, VGA BIOS and keymaps.
3353 To list all the data directories, use @code{-L help}.
3356 DEF("bios
", HAS_ARG, QEMU_OPTION_bios, \
3357 "-bios file set the filename
for the BIOS
\n", QEMU_ARCH_ALL)
3359 @item -bios @var{file}
3361 Set the filename for the BIOS.
3364 DEF("enable
-kvm
", 0, QEMU_OPTION_enable_kvm, \
3365 "-enable
-kvm enable KVM full virtualization support
\n", QEMU_ARCH_ALL)
3369 Enable KVM full virtualization support. This option is only available
3370 if KVM support is enabled when compiling.
3373 DEF("enable
-hax
", 0, QEMU_OPTION_enable_hax, \
3374 "-enable
-hax enable HAX virtualization support
\n", QEMU_ARCH_I386)
3378 Enable HAX (Hardware-based Acceleration eXecution) support. This option
3379 is only available if HAX support is enabled when compiling. HAX is only
3380 applicable to MAC and Windows platform, and thus does not conflict with
3384 DEF("xen
-domid
", HAS_ARG, QEMU_OPTION_xen_domid,
3385 "-xen
-domid id specify xen guest domain id
\n", QEMU_ARCH_ALL)
3386 DEF("xen
-create
", 0, QEMU_OPTION_xen_create,
3387 "-xen
-create create domain
using xen hypercalls
, bypassing xend
\n"
3388 " warning
: should not be used when xend is
in use
\n",
3390 DEF("xen
-attach
", 0, QEMU_OPTION_xen_attach,
3391 "-xen
-attach attach to existing xen domain
\n"
3392 " xend will use
this when starting QEMU
\n",
3394 DEF("xen
-domid
-restrict
", 0, QEMU_OPTION_xen_domid_restrict,
3395 "-xen
-domid
-restrict restrict set of available xen operations
\n"
3396 " to specified domain id
. (Does not affect
\n"
3397 " xenpv machine type
).\n",
3400 @item -xen-domid @var{id}
3402 Specify xen guest domain @var{id} (XEN only).
3405 Create domain using xen hypercalls, bypassing xend.
3406 Warning: should not be used when xend is in use (XEN only).
3409 Attach to existing xen domain.
3410 xend will use this when starting QEMU (XEN only).
3411 @findex -xen-domid-restrict
3412 Restrict set of available xen operations to specified domain id (XEN only).
3415 DEF("no
-reboot
", 0, QEMU_OPTION_no_reboot, \
3416 "-no
-reboot exit instead of rebooting
\n", QEMU_ARCH_ALL)
3420 Exit instead of rebooting.
3423 DEF("no
-shutdown
", 0, QEMU_OPTION_no_shutdown, \
3424 "-no
-shutdown stop before shutdown
\n", QEMU_ARCH_ALL)
3427 @findex -no-shutdown
3428 Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3429 This allows for instance switching to monitor to commit changes to the
3433 DEF("loadvm
", HAS_ARG, QEMU_OPTION_loadvm, \
3434 "-loadvm
[tag|id
]\n" \
3435 " start right away with a saved
state (loadvm
in monitor
)\n",
3438 @item -loadvm @var{file}
3440 Start right away with a saved state (@code{loadvm} in monitor)
3444 DEF("daemonize
", 0, QEMU_OPTION_daemonize, \
3445 "-daemonize daemonize QEMU after initializing
\n", QEMU_ARCH_ALL)
3450 Daemonize the QEMU process after initialization. QEMU will not detach from
3451 standard IO until it is ready to receive connections on any of its devices.
3452 This option is a useful way for external programs to launch QEMU without having
3453 to cope with initialization race conditions.
3456 DEF("option
-rom
", HAS_ARG, QEMU_OPTION_option_rom, \
3457 "-option
-rom rom load a file
, rom
, into the option ROM space
\n",
3460 @item -option-rom @var{file}
3462 Load the contents of @var{file} as an option ROM.
3463 This option is useful to load things like EtherBoot.
3466 HXCOMM Silently ignored for compatibility
3467 DEF("clock
", HAS_ARG, QEMU_OPTION_clock, "", QEMU_ARCH_ALL)
3469 HXCOMM Options deprecated by -rtc
3470 DEF("localtime
", 0, QEMU_OPTION_localtime, "", QEMU_ARCH_ALL)
3471 DEF("startdate
", HAS_ARG, QEMU_OPTION_startdate, "", QEMU_ARCH_ALL)
3473 DEF("rtc
", HAS_ARG, QEMU_OPTION_rtc, \
3474 "-rtc
[base
=utc|localtime|date
][,clock
=host|rt|vm
][,driftfix
=none|slew
]\n" \
3475 " set the RTC base and clock
, enable drift fix
for clock
ticks (x86 only
)\n",
3480 @item -rtc [base=utc|localtime|@var{date}][,clock=host|vm][,driftfix=none|slew]
3482 Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3483 UTC or local time, respectively. @code{localtime} is required for correct date in
3484 MS-DOS or Windows. To start at a specific point in time, provide @var{date} in the
3485 format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3487 By default the RTC is driven by the host system time. This allows using of the
3488 RTC as accurate reference clock inside the guest, specifically if the host
3489 time is smoothly following an accurate external reference clock, e.g. via NTP.
3490 If you want to isolate the guest time from the host, you can set @option{clock}
3491 to @code{rt} instead. To even prevent it from progressing during suspension,
3492 you can set it to @code{vm}.
3494 Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3495 specifically with Windows' ACPI HAL. This option will try to figure out how
3496 many timer interrupts were not processed by the Windows guest and will
3500 DEF("icount
", HAS_ARG, QEMU_OPTION_icount, \
3501 "-icount
[shift
=N|auto
][,align
=on|off
][,sleep
=on|off
,rr
=record|replay
,rrfile
=<filename
>,rrsnapshot
=<snapshot
>]\n" \
3502 " enable virtual instruction counter with
2^N clock ticks per
\n" \
3503 " instruction
, enable aligning the host and virtual clocks
\n" \
3504 " or disable real time cpu sleeping
\n", QEMU_ARCH_ALL)
3506 @item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3508 Enable virtual instruction counter. The virtual cpu will execute one
3509 instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified
3510 then the virtual cpu speed will be automatically adjusted to keep virtual
3511 time within a few seconds of real time.
3513 When the virtual cpu is sleeping, the virtual time will advance at default
3514 speed unless @option{sleep=on|off} is specified.
3515 With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3516 instantly whenever the virtual cpu goes to sleep mode and will not advance
3517 if no timer is enabled. This behavior give deterministic execution times from
3518 the guest point of view.
3520 Note that while this option can give deterministic behavior, it does not
3521 provide cycle accurate emulation. Modern CPUs contain superscalar out of
3522 order cores with complex cache hierarchies. The number of instructions
3523 executed often has little or no correlation with actual performance.
3525 @option{align=on} will activate the delay algorithm which will try
3526 to synchronise the host clock and the virtual clock. The goal is to
3527 have a guest running at the real frequency imposed by the shift option.
3528 Whenever the guest clock is behind the host clock and if
3529 @option{align=on} is specified then we print a message to the user
3530 to inform about the delay.
3531 Currently this option does not work when @option{shift} is @code{auto}.
3532 Note: The sync algorithm will work for those shift values for which
3533 the guest clock runs ahead of the host clock. Typically this happens
3534 when the shift value is high (how high depends on the host machine).
3536 When @option{rr} option is specified deterministic record/replay is enabled.
3537 Replay log is written into @var{filename} file in record mode and
3538 read from this file in replay mode.
3540 Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3541 at the start of execution recording. In replay mode this option is used
3542 to load the initial VM state.
3545 DEF("watchdog
", HAS_ARG, QEMU_OPTION_watchdog, \
3546 "-watchdog model
\n" \
3547 " enable virtual hardware watchdog
[default=none
]\n",
3550 @item -watchdog @var{model}
3552 Create a virtual hardware watchdog device. Once enabled (by a guest
3553 action), the watchdog must be periodically polled by an agent inside
3554 the guest or else the guest will be restarted. Choose a model for
3555 which your guest has drivers.
3557 The @var{model} is the model of hardware watchdog to emulate. Use
3558 @code{-watchdog help} to list available hardware models. Only one
3559 watchdog can be enabled for a guest.
3561 The following models may be available:
3564 iBASE 700 is a very simple ISA watchdog with a single timer.
3566 Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3567 dual-timer watchdog.
3569 A virtual watchdog for s390x backed by the diagnose 288 hypercall
3570 (currently KVM only).
3574 DEF("watchdog
-action
", HAS_ARG, QEMU_OPTION_watchdog_action, \
3575 "-watchdog
-action reset|shutdown|poweroff|pause|debug|none
\n" \
3576 " action when watchdog fires
[default=reset
]\n",
3579 @item -watchdog-action @var{action}
3580 @findex -watchdog-action
3582 The @var{action} controls what QEMU will do when the watchdog timer
3585 @code{reset} (forcefully reset the guest).
3586 Other possible actions are:
3587 @code{shutdown} (attempt to gracefully shutdown the guest),
3588 @code{poweroff} (forcefully poweroff the guest),
3589 @code{pause} (pause the guest),
3590 @code{debug} (print a debug message and continue), or
3591 @code{none} (do nothing).
3593 Note that the @code{shutdown} action requires that the guest responds
3594 to ACPI signals, which it may not be able to do in the sort of
3595 situations where the watchdog would have expired, and thus
3596 @code{-watchdog-action shutdown} is not recommended for production use.
3601 @item -watchdog i6300esb -watchdog-action pause
3602 @itemx -watchdog ib700
3606 DEF("echr
", HAS_ARG, QEMU_OPTION_echr, \
3607 "-echr chr set terminal escape character instead of ctrl
-a
\n",
3611 @item -echr @var{numeric_ascii_value}
3613 Change the escape character used for switching to the monitor when using
3614 monitor and serial sharing. The default is @code{0x01} when using the
3615 @code{-nographic} option. @code{0x01} is equal to pressing
3616 @code{Control-a}. You can select a different character from the ascii
3617 control keys where 1 through 26 map to Control-a through Control-z. For
3618 instance you could use the either of the following to change the escape
3619 character to Control-t.
3626 DEF("virtioconsole
", HAS_ARG, QEMU_OPTION_virtiocon, \
3627 "-virtioconsole c
\n" \
3628 " set virtio console
\n", QEMU_ARCH_ALL)
3630 @item -virtioconsole @var{c}
3631 @findex -virtioconsole
3634 This option is maintained for backward compatibility.
3636 Please use @code{-device virtconsole} for the new way of invocation.
3639 DEF("show
-cursor
", 0, QEMU_OPTION_show_cursor, \
3640 "-show
-cursor show cursor
\n", QEMU_ARCH_ALL)
3643 @findex -show-cursor
3647 DEF("tb
-size
", HAS_ARG, QEMU_OPTION_tb_size, \
3648 "-tb
-size n set TB size
\n", QEMU_ARCH_ALL)
3650 @item -tb-size @var{n}
3655 DEF("incoming
", HAS_ARG, QEMU_OPTION_incoming, \
3656 "-incoming tcp
:[host
]:port
[,to
=maxport
][,ipv4
][,ipv6
]\n" \
3657 "-incoming rdma
:host
:port
[,ipv4
][,ipv6
]\n" \
3658 "-incoming unix
:socketpath
\n" \
3659 " prepare
for incoming migration
, listen on
\n" \
3660 " specified protocol and socket address
\n" \
3661 "-incoming fd
:fd
\n" \
3662 "-incoming exec
:cmdline
\n" \
3663 " accept incoming migration on given file descriptor
\n" \
3664 " or from given external command
\n" \
3665 "-incoming defer
\n" \
3666 " wait
for the URI to be specified via migrate_incoming
\n",
3669 @item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
3670 @itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
3672 Prepare for incoming migration, listen on a given tcp port.
3674 @item -incoming unix:@var{socketpath}
3675 Prepare for incoming migration, listen on a given unix socket.
3677 @item -incoming fd:@var{fd}
3678 Accept incoming migration from a given filedescriptor.
3680 @item -incoming exec:@var{cmdline}
3681 Accept incoming migration as an output from specified external command.
3683 @item -incoming defer
3684 Wait for the URI to be specified via migrate_incoming. The monitor can
3685 be used to change settings (such as migration parameters) prior to issuing
3686 the migrate_incoming to allow the migration to begin.
3689 DEF("only
-migratable
", 0, QEMU_OPTION_only_migratable, \
3690 "-only
-migratable allow only migratable devices
\n", QEMU_ARCH_ALL)
3692 @item -only-migratable
3693 @findex -only-migratable
3694 Only allow migratable devices. Devices will not be allowed to enter an
3698 DEF("nodefaults
", 0, QEMU_OPTION_nodefaults, \
3699 "-nodefaults don
't create default devices\n", QEMU_ARCH_ALL)
3703 Don't create
default devices
. Normally
, QEMU sets the
default devices like serial
3704 port
, parallel port
, virtual console
, monitor device
, VGA adapter
, floppy and
3705 CD
-ROM drive and others
. The @code
{-nodefaults
} option will disable all those
3710 DEF("chroot", HAS_ARG
, QEMU_OPTION_chroot
, \
3711 "-chroot dir chroot to dir just before starting the VM\n",
3715 @item
-chroot @
var{dir
}
3717 Immediately before starting guest execution
, chroot to the specified
3718 directory
. Especially useful
in combination with
-runas
.
3722 DEF("runas", HAS_ARG
, QEMU_OPTION_runas
, \
3723 "-runas user change to user id user just before starting the VM\n",
3727 @item
-runas @
var{user
}
3729 Immediately before starting guest execution
, drop root privileges
, switching
3730 to the specified user
.
3733 DEF("prom-env", HAS_ARG
, QEMU_OPTION_prom_env
,
3734 "-prom-env variable=value\n"
3735 " set OpenBIOS nvram variables\n",
3736 QEMU_ARCH_PPC | QEMU_ARCH_SPARC
)
3738 @item
-prom
-env @
var{variable
}=@
var{value
}
3740 Set OpenBIOS nvram @
var{variable
} to given @
var{value
} (PPC
, SPARC only
).
3742 DEF("semihosting", 0, QEMU_OPTION_semihosting
,
3743 "-semihosting semihosting mode\n",
3744 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3748 @findex
-semihosting
3749 Enable semihosting
mode (ARM
, M68K
, Xtensa
, MIPS only
).
3751 DEF("semihosting-config", HAS_ARG
, QEMU_OPTION_semihosting_config
,
3752 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
3753 " semihosting configuration\n",
3754 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3757 @item
-semihosting
-config
[enable
=on|off
][,target
=native|gdb|auto
][,arg
=str
[,...]]
3758 @findex
-semihosting
-config
3759 Enable and configure
semihosting (ARM
, M68K
, Xtensa
, MIPS only
).
3761 @item target
=@code
{native|gdb|auto
}
3762 Defines where the semihosting calls will be addressed
, to
QEMU (@code
{native
})
3763 or to
GDB (@code
{gdb
}). The
default is @code
{auto
}, which means @code
{gdb
}
3764 during debug sessions and @code
{native
} otherwise
.
3765 @item arg
=@
var{str1
},arg
=@
var{str2
},...
3766 Allows the user to pass input arguments
, and can be used multiple times to build
3767 up a list
. The old
-style @code
{-kernel
}/@code
{-append
} method of passing a
3768 command line is still supported
for backward compatibility
. If both the
3769 @code
{--semihosting
-config arg
} and the @code
{-kernel
}/@code
{-append
} are
3770 specified
, the former is passed to semihosting as it always takes precedence
.
3773 DEF("old-param", 0, QEMU_OPTION_old_param
,
3774 "-old-param old param mode\n", QEMU_ARCH_ARM
)
3777 @findex
-old
-param (ARM
)
3778 Old param
mode (ARM only
).
3781 DEF("sandbox", HAS_ARG
, QEMU_OPTION_sandbox
, \
3782 "-sandbox <arg> Enable seccomp mode 2 system call filter (default 'off').\n",
3785 @item
-sandbox @
var{arg
}
3787 Enable Seccomp mode
2 system call filter
. 'on' will enable syscall filtering and
'off' will
3788 disable it
. The
default is
'off'.
3791 DEF("readconfig", HAS_ARG
, QEMU_OPTION_readconfig
,
3792 "-readconfig <file>\n", QEMU_ARCH_ALL
)
3794 @item
-readconfig @
var{file
}
3796 Read device configuration from @
var{file
}. This approach is useful when you want to spawn
3797 QEMU process with many command line options but you don
't want to exceed the command line
3800 DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
3801 "-writeconfig <file>\n"
3802 " read/write config file\n", QEMU_ARCH_ALL)
3804 @item -writeconfig @var{file}
3805 @findex -writeconfig
3806 Write device configuration to @var{file}. The @var{file} can be either filename to save
3807 command line and device configuration into file or dash @code{-}) character to print the
3808 output to stdout. This can be later used as input file for @code{-readconfig} option.
3810 DEF("nodefconfig", 0, QEMU_OPTION_nodefconfig,
3812 " do not load default config files at startup\n",
3816 @findex -nodefconfig
3817 Normally QEMU loads configuration files from @var{sysconfdir} and @var{datadir} at startup.
3818 The @code{-nodefconfig} option will prevent QEMU from loading any of those config files.
3820 DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
3822 " do not load user-provided config files at startup\n",
3825 @item -no-user-config
3826 @findex -no-user-config
3827 The @code{-no-user-config} option makes QEMU not load any of the user-provided
3828 config files on @var{sysconfdir}, but won't make it skip the QEMU
-provided config
3829 files from @
var{datadir
}.
3831 DEF("trace", HAS_ARG
, QEMU_OPTION_trace
,
3832 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
3833 " specify tracing options\n",
3836 HXCOMM This line is not accurate
, as some sub
-options are backend
-specific but
3837 HXCOMM HX does not support conditional compilation of text
.
3838 @item
-trace [[enable
=]@
var{pattern
}][,events
=@
var{file
}][,file
=@
var{file
}]
3840 @include qemu
-option
-trace.texi
3844 DEF("qtest", HAS_ARG
, QEMU_OPTION_qtest
, "", QEMU_ARCH_ALL
)
3845 DEF("qtest-log", HAS_ARG
, QEMU_OPTION_qtest_log
, "", QEMU_ARCH_ALL
)
3848 DEF("enable-fips", 0, QEMU_OPTION_enablefips
,
3849 "-enable-fips enable FIPS 140-2 compliance\n",
3854 @findex
-enable
-fips
3855 Enable FIPS
140-2 compliance mode
.
3858 HXCOMM Deprecated by
-machine accel
=tcg property
3859 DEF("no-kvm", 0, QEMU_OPTION_no_kvm
, "", QEMU_ARCH_I386
)
3861 HXCOMM Deprecated by kvm
-pit driver properties
3862 DEF("no-kvm-pit-reinjection", 0, QEMU_OPTION_no_kvm_pit_reinjection
,
3865 HXCOMM
Deprecated (ignored
)
3866 DEF("no-kvm-pit", 0, QEMU_OPTION_no_kvm_pit
, "", QEMU_ARCH_I386
)
3868 HXCOMM Deprecated by
-machine kernel_irqchip
=on|off property
3869 DEF("no-kvm-irqchip", 0, QEMU_OPTION_no_kvm_irqchip
, "", QEMU_ARCH_I386
)
3871 HXCOMM
Deprecated (ignored
)
3872 DEF("tdf", 0, QEMU_OPTION_tdf
,"", QEMU_ARCH_ALL
)
3874 DEF("msg", HAS_ARG
, QEMU_OPTION_msg
,
3875 "-msg timestamp[=on|off]\n"
3876 " change the format of messages\n"
3877 " on|off controls leading timestamps (default:on)\n",
3880 @item
-msg timestamp
[=on|off
]
3882 prepend a timestamp to each log message
.(default:on
)
3885 DEF("dump-vmstate", HAS_ARG
, QEMU_OPTION_dump_vmstate
,
3886 "-dump-vmstate <file>\n"
3887 " Output vmstate information in JSON format to file.\n"
3888 " Use the scripts/vmstate-static-checker.py file to\n"
3889 " check for possible regressions in migration code\n"
3890 " by comparing two such vmstate dumps.\n",
3893 @item
-dump
-vmstate @
var{file
}
3894 @findex
-dump
-vmstate
3895 Dump json
-encoded vmstate information
for current machine type to file
3903 DEFHEADING(Generic object creation
)
3908 DEF("object", HAS_ARG
, QEMU_OPTION_object
,
3909 "-object TYPENAME[,PROP1=VALUE1,...]\n"
3910 " create a new object of type TYPENAME setting properties\n"
3911 " in the order they are specified. Note that the 'id'\n"
3912 " property must be set. These objects are placed in the\n"
3913 " '/objects' path.\n",
3916 @item
-object @
var{typename
}[,@
var{prop1
}=@
var{value1
},...]
3918 Create a
new object of type @
var{typename
} setting properties
3919 in the order they are specified
. Note that the
'id'
3920 property must be set
. These objects are placed
in the
3925 @item
-object memory
-backend
-file
,id
=@
var{id
},size
=@
var{size
},mem
-path
=@
var{dir
},share
=@
var{on|off
}
3927 Creates a memory file backend object
, which can be used to back
3928 the guest RAM with huge pages
. The @option
{id
} parameter is a
3929 unique ID that will be used to reference
this memory region
3930 when configuring the @option
{-numa
} argument
. The @option
{size
}
3931 option provides the size of the memory region
, and accepts
3932 common suffixes
, eg @option
{500M
}. The @option
{mem
-path
} provides
3933 the path to either a shared memory or huge page filesystem mount
.
3934 The @option
{share
} boolean option determines whether the memory
3935 region is marked as
private to QEMU
, or shared
. The latter allows
3936 a co
-operating external process to access the QEMU memory region
.
3938 @item
-object rng
-random
,id
=@
var{id
},filename
=@
var{/dev
/random
}
3940 Creates a random number generator backend which obtains entropy from
3941 a device on the host
. The @option
{id
} parameter is a unique ID that
3942 will be used to reference
this entropy backend from the @option
{virtio
-rng
}
3943 device
. The @option
{filename
} parameter specifies which file to obtain
3944 entropy from and
if omitted defaults to @option
{/dev
/random
}.
3946 @item
-object rng
-egd
,id
=@
var{id
},chardev
=@
var{chardevid
}
3948 Creates a random number generator backend which obtains entropy from
3949 an external daemon running on the host
. The @option
{id
} parameter is
3950 a unique ID that will be used to reference
this entropy backend from
3951 the @option
{virtio
-rng
} device
. The @option
{chardev
} parameter is
3952 the unique ID of a character device backend that provides the connection
3955 @item
-object tls
-creds
-anon
,id
=@
var{id
},endpoint
=@
var{endpoint
},dir
=@
var{/path
/to
/cred
/dir
},verify
-peer
=@
var{on|off
}
3957 Creates a TLS anonymous credentials object
, which can be used to provide
3958 TLS support on network backends
. The @option
{id
} parameter is a unique
3959 ID which network backends will use to access the credentials
. The
3960 @option
{endpoint
} is either @option
{server
} or @option
{client
} depending
3961 on whether the QEMU network backend that uses the credentials will be
3962 acting as a client or as a server
. If @option
{verify
-peer
} is enabled
3963 (the
default) then once the handshake is completed
, the peer credentials
3964 will be verified
, though
this is a no
-op
for anonymous credentials
.
3966 The @
var{dir
} parameter tells QEMU where to find the credential
3967 files
. For server endpoints
, this directory may contain a file
3968 @
var{dh
-params
.pem
} providing diffie
-hellman parameters to use
3969 for the TLS server
. If the file is missing
, QEMU will generate
3970 a set of DH parameters at startup
. This is a computationally
3971 expensive operation that consumes random pool entropy
, so it is
3972 recommended that a persistent set of parameters be generated
3975 @item
-object tls
-creds
-x509
,id
=@
var{id
},endpoint
=@
var{endpoint
},dir
=@
var{/path
/to
/cred
/dir
},verify
-peer
=@
var{on|off
},passwordid
=@
var{id
}
3977 Creates a TLS anonymous credentials object
, which can be used to provide
3978 TLS support on network backends
. The @option
{id
} parameter is a unique
3979 ID which network backends will use to access the credentials
. The
3980 @option
{endpoint
} is either @option
{server
} or @option
{client
} depending
3981 on whether the QEMU network backend that uses the credentials will be
3982 acting as a client or as a server
. If @option
{verify
-peer
} is enabled
3983 (the
default) then once the handshake is completed
, the peer credentials
3984 will be verified
. With x509 certificates
, this implies that the clients
3985 must be provided with valid client certificates too
.
3987 The @
var{dir
} parameter tells QEMU where to find the credential
3988 files
. For server endpoints
, this directory may contain a file
3989 @
var{dh
-params
.pem
} providing diffie
-hellman parameters to use
3990 for the TLS server
. If the file is missing
, QEMU will generate
3991 a set of DH parameters at startup
. This is a computationally
3992 expensive operation that consumes random pool entropy
, so it is
3993 recommended that a persistent set of parameters be generated
3996 For x509 certificate credentials the directory will contain further files
3997 providing the x509 certificates
. The certificates must be stored
3998 in PEM format
, in filenames @
var{ca
-cert
.pem
}, @
var{ca
-crl
.pem
} (optional
),
3999 @
var{server
-cert
.pem
} (only servers
), @
var{server
-key
.pem
} (only servers
),
4000 @
var{client
-cert
.pem
} (only clients
), and @
var{client
-key
.pem
} (only clients
).
4002 For the @
var{server
-key
.pem
} and @
var{client
-key
.pem
} files which
4003 contain sensitive
private keys
, it is possible to use an encrypted
4004 version by providing the @
var{passwordid
} parameter
. This provides
4005 the ID of a previously created @code
{secret
} object containing the
4006 password
for decryption
.
4008 @item
-object filter
-buffer
,id
=@
var{id
},netdev
=@
var{netdevid
},interval
=@
var{t
}[,queue
=@
var{all|rx|tx
}][,status
=@
var{on|off
}]
4010 Interval @
var{t
} can
't be 0, this filter batches the packet delivery: all
4011 packets arriving in a given interval on netdev @var{netdevid} are delayed
4012 until the end of the interval. Interval is in microseconds.
4013 @option{status} is optional that indicate whether the netfilter is
4014 on (enabled) or off (disabled), the default status for netfilter will be 'on
'.
4016 queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4018 @option{all}: the filter is attached both to the receive and the transmit
4019 queue of the netdev (default).
4021 @option{rx}: the filter is attached to the receive queue of the netdev,
4022 where it will receive packets sent to the netdev.
4024 @option{tx}: the filter is attached to the transmit queue of the netdev,
4025 where it will receive packets sent by the netdev.
4027 @item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid}[,queue=@var{all|rx|tx}]
4029 filter-mirror on netdev @var{netdevid},mirror net packet to chardev
4032 @item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},
4033 outdev=@var{chardevid}[,queue=@var{all|rx|tx}]
4035 filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4036 @
var{chardevid
},and redirect indev
's packet to filter.
4037 Create a filter-redirector we need to differ outdev id from indev id, id can not
4038 be the same. we can just use indev or outdev, but at least one of indev or outdev
4039 need to be specified.
4041 @item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},rewriter-mode=@var{mode}[,queue=@var{all|rx|tx}]
4043 Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4044 secondary from primary to keep secondary tcp connection,and rewrite
4045 tcp packet to primary from secondary make tcp packet can be handled by
4050 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4051 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4052 -object filter-rewriter,id=rew0,netdev=hn0,queue=all
4054 @item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4056 Dump the network traffic on netdev @var{dev} to the file specified by
4057 @var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4058 The file format is libpcap, so it can be analyzed with tools such as tcpdump
4061 @item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},
4062 outdev=@var{chardevid}
4064 Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4065 secondary packet. If the packets are same, we will output primary
4066 packet to outdev@var{chardevid}, else we will notify colo-frame
4067 do checkpoint and send primary packet to outdev@var{chardevid}.
4069 we must use it with the help of filter-mirror and filter-redirector.
4074 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4075 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4076 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4077 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4078 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4079 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4080 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4081 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4082 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4083 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4084 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4085 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
4088 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4089 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4090 -chardev socket,id=red0,host=3.3.3.3,port=9003
4091 -chardev socket,id=red1,host=3.3.3.3,port=9004
4092 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4093 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4097 If you want to know the detail of above command line, you can read
4098 the colo-compare git log.
4100 @item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4102 Creates a cryptodev backend which executes crypto opreation from
4103 the QEMU cipher APIS. The @var{id} parameter is
4104 a unique ID that will be used to reference this cryptodev backend from
4105 the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4106 which specify the queue number of cryptodev backend, the default of
4111 # qemu-system-x86_64 \
4113 -object cryptodev-backend-builtin,id=cryptodev0 \
4114 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4118 @item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4119 @item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4121 Defines a secret to store a password, encryption key, or some other sensitive
4122 data. The sensitive data can either be passed directly via the @var{data}
4123 parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4124 parameter is insecure unless the sensitive data is encrypted.
4126 The sensitive data can be provided in raw format (the default), or base64.
4127 When encoded as JSON, the raw format only supports valid UTF-8 characters,
4128 so base64 is recommended for sending binary data. QEMU will convert from
4129 which ever format is provided to the format it needs internally. eg, an
4130 RBD password can be provided in raw format, even though it will be base64
4131 encoded when passed onto the RBD sever.
4133 For added protection, it is possible to encrypt the data associated with
4134 a secret using the AES-256-CBC cipher. Use of encryption is indicated
4135 by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4136 parameter provides the ID of a previously defined secret that contains
4137 the AES-256 decryption key. This key should be 32-bytes long and be
4138 base64 encoded. The @var{iv} parameter provides the random initialization
4139 vector used for encryption of this particular secret and should be a
4140 base64 encrypted string of the 16-byte IV.
4142 The simplest (insecure) usage is to provide the secret inline
4146 # $QEMU -object secret,id=sec0,data=letmein,format=raw
4150 The simplest secure usage is to provide the secret via a file
4152 # echo -n "letmein" > mypasswd.txt
4153 # $QEMU -object secret,id=sec0,file=mypasswd.txt,format=raw
4155 For greater security, AES-256-CBC should be used. To illustrate usage,
4156 consider the openssl command line tool which can encrypt the data. Note
4157 that when encrypting, the plaintext must be padded to the cipher block
4158 size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4160 First a master key needs to be created in base64 encoding:
4163 # openssl rand -base64 32 > key.b64
4164 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"')
4167 Each secret to be encrypted needs to have a random initialization vector
4168 generated. These do not need to be kept secret
4171 # openssl rand -base64 16 > iv.b64
4172 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"')
4175 The secret to be defined can now be encrypted, in this case we're
4176 telling openssl to base64 encode the result
, but it could be left
4177 as raw bytes
if desired
.
4180 # SECRET
=$
(echo
-n
"letmein" |
4181 openssl enc
-aes
-256-cbc
-a
-K $KEY
-iv $IV
)
4184 When launching QEMU
, create a master secret pointing to @code
{key
.b64
}
4185 and specify that to be used to decrypt the user password
. Pass the
4186 contents of @code
{iv
.b64
} to the second secret
4190 -object secret
,id
=secmaster0
,format
=base64
,file
=key
.b64 \
4191 -object secret
,id
=sec0
,keyid
=secmaster0
,format
=base64
,\
4192 data
=$SECRET
,iv
=$
(<iv
.b64
)
4200 HXCOMM This is the last statement
. Insert
new options before
this line
!