xref: /openbmc/qemu/qemu-options.hx (revision 7520462bc1eeda2f724ec84ff16338053b728920)
1HXCOMM Use DEFHEADING() to define headings in both help text and texi
2HXCOMM Text between STEXI and ETEXI are copied to texi version and
3HXCOMM discarded from C version
4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to
5HXCOMM construct option structures, enums and help message for specified
6HXCOMM architectures.
7HXCOMM HXCOMM can be used for comments, discarded from both texi and C
8
9DEFHEADING(Standard options:)
10STEXI
11@table @option
12ETEXI
13
14DEF("help", 0, QEMU_OPTION_h,
15    "-h or -help     display this help and exit\n", QEMU_ARCH_ALL)
16STEXI
17@item -h
18@findex -h
19Display help and exit
20ETEXI
21
22DEF("version", 0, QEMU_OPTION_version,
23    "-version        display version information and exit\n", QEMU_ARCH_ALL)
24STEXI
25@item -version
26@findex -version
27Display version information and exit
28ETEXI
29
30DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
31    "-machine [type=]name[,prop[=value][,...]]\n"
32    "                selects emulated machine ('-machine help' for list)\n"
33    "                property accel=accel1[:accel2[:...]] selects accelerator\n"
34    "                supported accelerators are kvm, xen, hax, hvf, whpx or tcg (default: tcg)\n"
35    "                kernel_irqchip=on|off|split controls accelerated irqchip support (default=off)\n"
36    "                vmport=on|off|auto controls emulation of vmport (default: auto)\n"
37    "                kvm_shadow_mem=size of KVM shadow MMU in bytes\n"
38    "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
39    "                mem-merge=on|off controls memory merge support (default: on)\n"
40    "                igd-passthru=on|off controls IGD GFX passthrough support (default=off)\n"
41    "                aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
42    "                dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
43    "                suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
44    "                nvdimm=on|off controls NVDIMM support (default=off)\n"
45    "                enforce-config-section=on|off enforce configuration section migration (default=off)\n"
46    "                memory-encryption=@var{} memory encryption object to use (default=none)\n",
47    QEMU_ARCH_ALL)
48STEXI
49@item -machine [type=]@var{name}[,prop=@var{value}[,...]]
50@findex -machine
51Select the emulated machine by @var{name}. Use @code{-machine help} to list
52available machines.
53
54For architectures which aim to support live migration compatibility
55across releases, each release will introduce a new versioned machine
56type. For example, the 2.8.0 release introduced machine types
57``pc-i440fx-2.8'' and ``pc-q35-2.8'' for the x86_64/i686 architectures.
58
59To allow live migration of guests from QEMU version 2.8.0, to QEMU
60version 2.9.0, the 2.9.0 version must support the ``pc-i440fx-2.8''
61and ``pc-q35-2.8'' machines too. To allow users live migrating VMs
62to skip multiple intermediate releases when upgrading, new releases
63of QEMU will support machine types from many previous versions.
64
65Supported machine properties are:
66@table @option
67@item accel=@var{accels1}[:@var{accels2}[:...]]
68This is used to enable an accelerator. Depending on the target architecture,
69kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is
70more than one accelerator specified, the next one is used if the previous one
71fails to initialize.
72@item kernel_irqchip=on|off
73Controls in-kernel irqchip support for the chosen accelerator when available.
74@item gfx_passthru=on|off
75Enables IGD GFX passthrough support for the chosen machine when available.
76@item vmport=on|off|auto
77Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the
78value based on accel. For accel=xen the default is off otherwise the default
79is on.
80@item kvm_shadow_mem=size
81Defines the size of the KVM shadow MMU.
82@item dump-guest-core=on|off
83Include guest memory in a core dump. The default is on.
84@item mem-merge=on|off
85Enables or disables memory merge support. This feature, when supported by
86the host, de-duplicates identical memory pages among VMs instances
87(enabled by default).
88@item aes-key-wrap=on|off
89Enables or disables AES key wrapping support on s390-ccw hosts. This feature
90controls whether AES wrapping keys will be created to allow
91execution of AES cryptographic functions.  The default is on.
92@item dea-key-wrap=on|off
93Enables or disables DEA key wrapping support on s390-ccw hosts. This feature
94controls whether DEA wrapping keys will be created to allow
95execution of DEA cryptographic functions.  The default is on.
96@item nvdimm=on|off
97Enables or disables NVDIMM support. The default is off.
98@item enforce-config-section=on|off
99If @option{enforce-config-section} is set to @var{on}, force migration
100code to send configuration section even if the machine-type sets the
101@option{migration.send-configuration} property to @var{off}.
102NOTE: this parameter is deprecated. Please use @option{-global}
103@option{migration.send-configuration}=@var{on|off} instead.
104@item memory-encryption=@var{}
105Memory encryption object to use. The default is none.
106@end table
107ETEXI
108
109HXCOMM Deprecated by -machine
110DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL)
111
112DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
113    "-cpu cpu        select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL)
114STEXI
115@item -cpu @var{model}
116@findex -cpu
117Select CPU model (@code{-cpu help} for list and additional feature selection)
118ETEXI
119
120DEF("accel", HAS_ARG, QEMU_OPTION_accel,
121    "-accel [accel=]accelerator[,thread=single|multi]\n"
122    "                select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n"
123    "                thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
124STEXI
125@item -accel @var{name}[,prop=@var{value}[,...]]
126@findex -accel
127This is used to enable an accelerator. Depending on the target architecture,
128kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If there is
129more than one accelerator specified, the next one is used if the previous one
130fails to initialize.
131@table @option
132@item thread=single|multi
133Controls number of TCG threads. When the TCG is multi-threaded there will be one
134thread per vCPU therefor taking advantage of additional host cores. The default
135is to enable multi-threading where both the back-end and front-ends support it and
136no incompatible TCG features have been enabled (e.g. icount/replay).
137@end table
138ETEXI
139
140DEF("smp", HAS_ARG, QEMU_OPTION_smp,
141    "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
142    "                set the number of CPUs to 'n' [default=1]\n"
143    "                maxcpus= maximum number of total cpus, including\n"
144    "                offline CPUs for hotplug, etc\n"
145    "                cores= number of CPU cores on one socket (for PC, it's on one die)\n"
146    "                threads= number of threads on one CPU core\n"
147    "                dies= number of CPU dies on one socket (for PC only)\n"
148    "                sockets= number of discrete sockets in the system\n",
149        QEMU_ARCH_ALL)
150STEXI
151@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,dies=dies][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
152@findex -smp
153Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
154CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
155to 4.
156For the PC target, the number of @var{cores} per die, the number of @var{threads}
157per cores, the number of @var{dies} per packages and the total number of
158@var{sockets} can be specified. Missing values will be computed.
159If any on the three values is given, the total number of CPUs @var{n} can be omitted.
160@var{maxcpus} specifies the maximum number of hotpluggable CPUs.
161ETEXI
162
163DEF("numa", HAS_ARG, QEMU_OPTION_numa,
164    "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
165    "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
166    "-numa dist,src=source,dst=destination,val=distance\n"
167    "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n",
168    QEMU_ARCH_ALL)
169STEXI
170@item -numa node[,mem=@var{size}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
171@itemx -numa node[,memdev=@var{id}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
172@itemx -numa dist,src=@var{source},dst=@var{destination},val=@var{distance}
173@itemx -numa cpu,node-id=@var{node}[,socket-id=@var{x}][,core-id=@var{y}][,thread-id=@var{z}]
174@findex -numa
175Define a NUMA node and assign RAM and VCPUs to it.
176Set the NUMA distance from a source node to a destination node.
177
178Legacy VCPU assignment uses @samp{cpus} option where
179@var{firstcpu} and @var{lastcpu} are CPU indexes. Each
180@samp{cpus} option represent a contiguous range of CPU indexes
181(or a single VCPU if @var{lastcpu} is omitted). A non-contiguous
182set of VCPUs can be represented by providing multiple @samp{cpus}
183options. If @samp{cpus} is omitted on all nodes, VCPUs are automatically
184split between them.
185
186For example, the following option assigns VCPUs 0, 1, 2 and 5 to
187a NUMA node:
188@example
189-numa node,cpus=0-2,cpus=5
190@end example
191
192@samp{cpu} option is a new alternative to @samp{cpus} option
193which uses @samp{socket-id|core-id|thread-id} properties to assign
194CPU objects to a @var{node} using topology layout properties of CPU.
195The set of properties is machine specific, and depends on used
196machine type/@samp{smp} options. It could be queried with
197@samp{hotpluggable-cpus} monitor command.
198@samp{node-id} property specifies @var{node} to which CPU object
199will be assigned, it's required for @var{node} to be declared
200with @samp{node} option before it's used with @samp{cpu} option.
201
202For example:
203@example
204-M pc \
205-smp 1,sockets=2,maxcpus=2 \
206-numa node,nodeid=0 -numa node,nodeid=1 \
207-numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
208@end example
209
210@samp{mem} assigns a given RAM amount to a node. @samp{memdev}
211assigns RAM from a given memory backend device to a node. If
212@samp{mem} and @samp{memdev} are omitted in all nodes, RAM is
213split equally between them.
214
215@samp{mem} and @samp{memdev} are mutually exclusive. Furthermore,
216if one node uses @samp{memdev}, all of them have to use it.
217
218@var{source} and @var{destination} are NUMA node IDs.
219@var{distance} is the NUMA distance from @var{source} to @var{destination}.
220The distance from a node to itself is always 10. If any pair of nodes is
221given a distance, then all pairs must be given distances. Although, when
222distances are only given in one direction for each pair of nodes, then
223the distances in the opposite directions are assumed to be the same. If,
224however, an asymmetrical pair of distances is given for even one node
225pair, then all node pairs must be provided distance values for both
226directions, even when they are symmetrical. When a node is unreachable
227from another node, set the pair's distance to 255.
228
229Note that the -@option{numa} option doesn't allocate any of the
230specified resources, it just assigns existing resources to NUMA
231nodes. This means that one still has to use the @option{-m},
232@option{-smp} options to allocate RAM and VCPUs respectively.
233
234ETEXI
235
236DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
237    "-add-fd fd=fd,set=set[,opaque=opaque]\n"
238    "                Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
239STEXI
240@item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}]
241@findex -add-fd
242
243Add a file descriptor to an fd set.  Valid options are:
244
245@table @option
246@item fd=@var{fd}
247This option defines the file descriptor of which a duplicate is added to fd set.
248The file descriptor cannot be stdin, stdout, or stderr.
249@item set=@var{set}
250This option defines the ID of the fd set to add the file descriptor to.
251@item opaque=@var{opaque}
252This option defines a free-form string that can be used to describe @var{fd}.
253@end table
254
255You can open an image using pre-opened file descriptors from an fd set:
256@example
257qemu-system-i386
258-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
259-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
260-drive file=/dev/fdset/2,index=0,media=disk
261@end example
262ETEXI
263
264DEF("set", HAS_ARG, QEMU_OPTION_set,
265    "-set group.id.arg=value\n"
266    "                set <arg> parameter for item <id> of type <group>\n"
267    "                i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
268STEXI
269@item -set @var{group}.@var{id}.@var{arg}=@var{value}
270@findex -set
271Set parameter @var{arg} for item @var{id} of type @var{group}
272ETEXI
273
274DEF("global", HAS_ARG, QEMU_OPTION_global,
275    "-global driver.property=value\n"
276    "-global driver=driver,property=property,value=value\n"
277    "                set a global default for a driver property\n",
278    QEMU_ARCH_ALL)
279STEXI
280@item -global @var{driver}.@var{prop}=@var{value}
281@itemx -global driver=@var{driver},property=@var{property},value=@var{value}
282@findex -global
283Set default value of @var{driver}'s property @var{prop} to @var{value}, e.g.:
284
285@example
286qemu-system-i386 -global ide-hd.physical_block_size=4096 disk-image.img
287@end example
288
289In particular, you can use this to set driver properties for devices which are
290created automatically by the machine model. To create a device which is not
291created automatically and set properties on it, use -@option{device}.
292
293-global @var{driver}.@var{prop}=@var{value} is shorthand for -global
294driver=@var{driver},property=@var{prop},value=@var{value}.  The
295longhand syntax works even when @var{driver} contains a dot.
296ETEXI
297
298DEF("boot", HAS_ARG, QEMU_OPTION_boot,
299    "-boot [order=drives][,once=drives][,menu=on|off]\n"
300    "      [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
301    "                'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
302    "                'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
303    "                'sp_time': the period that splash picture last if menu=on, unit is ms\n"
304    "                'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
305    QEMU_ARCH_ALL)
306STEXI
307@item -boot [order=@var{drives}][,once=@var{drives}][,menu=on|off][,splash=@var{sp_name}][,splash-time=@var{sp_time}][,reboot-timeout=@var{rb_timeout}][,strict=on|off]
308@findex -boot
309Specify boot order @var{drives} as a string of drive letters. Valid
310drive letters depend on the target architecture. The x86 PC uses: a, b
311(floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
312from network adapter 1-4), hard disk boot is the default. To apply a
313particular boot order only on the first startup, specify it via
314@option{once}. Note that the @option{order} or @option{once} parameter
315should not be used together with the @option{bootindex} property of
316devices, since the firmware implementations normally do not support both
317at the same time.
318
319Interactive boot menus/prompts can be enabled via @option{menu=on} as far
320as firmware/BIOS supports them. The default is non-interactive boot.
321
322A splash picture could be passed to bios, enabling user to show it as logo,
323when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
324supports them. Currently Seabios for X86 system support it.
325limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
326format(true color). The resolution should be supported by the SVGA mode, so
327the recommended is 320x240, 640x480, 800x640.
328
329A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
330when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
331reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
332system support it.
333
334Do strict boot via @option{strict=on} as far as firmware/BIOS
335supports it. This only effects when boot priority is changed by
336bootindex options. The default is non-strict boot.
337
338@example
339# try to boot from network first, then from hard disk
340qemu-system-i386 -boot order=nc
341# boot from CD-ROM first, switch back to default order after reboot
342qemu-system-i386 -boot once=d
343# boot with a splash picture for 5 seconds.
344qemu-system-i386 -boot menu=on,splash=/root/boot.bmp,splash-time=5000
345@end example
346
347Note: The legacy format '-boot @var{drives}' is still supported but its
348use is discouraged as it may be removed from future versions.
349ETEXI
350
351DEF("m", HAS_ARG, QEMU_OPTION_m,
352    "-m [size=]megs[,slots=n,maxmem=size]\n"
353    "                configure guest RAM\n"
354    "                size: initial amount of guest memory\n"
355    "                slots: number of hotplug slots (default: none)\n"
356    "                maxmem: maximum amount of guest memory (default: none)\n"
357    "NOTE: Some architectures might enforce a specific granularity\n",
358    QEMU_ARCH_ALL)
359STEXI
360@item -m [size=]@var{megs}[,slots=n,maxmem=size]
361@findex -m
362Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB.
363Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in
364megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem}
365could be used to set amount of hotpluggable memory slots and maximum amount of
366memory. Note that @var{maxmem} must be aligned to the page size.
367
368For example, the following command-line sets the guest startup RAM size to
3691GB, creates 3 slots to hotplug additional memory and sets the maximum
370memory the guest can reach to 4GB:
371
372@example
373qemu-system-x86_64 -m 1G,slots=3,maxmem=4G
374@end example
375
376If @var{slots} and @var{maxmem} are not specified, memory hotplug won't
377be enabled and the guest startup RAM will never increase.
378ETEXI
379
380DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
381    "-mem-path FILE  provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
382STEXI
383@item -mem-path @var{path}
384@findex -mem-path
385Allocate guest RAM from a temporarily created file in @var{path}.
386ETEXI
387
388DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
389    "-mem-prealloc   preallocate guest memory (use with -mem-path)\n",
390    QEMU_ARCH_ALL)
391STEXI
392@item -mem-prealloc
393@findex -mem-prealloc
394Preallocate memory when using -mem-path.
395ETEXI
396
397DEF("k", HAS_ARG, QEMU_OPTION_k,
398    "-k language     use keyboard layout (for example 'fr' for French)\n",
399    QEMU_ARCH_ALL)
400STEXI
401@item -k @var{language}
402@findex -k
403Use keyboard layout @var{language} (for example @code{fr} for
404French). This option is only needed where it is not easy to get raw PC
405keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
406display). You don't normally need to use it on PC/Linux or PC/Windows
407hosts.
408
409The available layouts are:
410@example
411ar  de-ch  es  fo     fr-ca  hu  ja  mk     no  pt-br  sv
412da  en-gb  et  fr     fr-ch  is  lt  nl     pl  ru     th
413de  en-us  fi  fr-be  hr     it  lv  nl-be  pt  sl     tr
414@end example
415
416The default is @code{en-us}.
417ETEXI
418
419
420HXCOMM Deprecated by -audiodev
421DEF("audio-help", 0, QEMU_OPTION_audio_help,
422    "-audio-help     show -audiodev equivalent of the currently specified audio settings\n",
423    QEMU_ARCH_ALL)
424STEXI
425@item -audio-help
426@findex -audio-help
427Will show the -audiodev equivalent of the currently specified
428(deprecated) environment variables.
429ETEXI
430
431DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
432    "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n"
433    "                specifies the audio backend to use\n"
434    "                id= identifier of the backend\n"
435    "                timer-period= timer period in microseconds\n"
436    "                in|out.fixed-settings= use fixed settings for host audio\n"
437    "                in|out.frequency= frequency to use with fixed settings\n"
438    "                in|out.channels= number of channels to use with fixed settings\n"
439    "                in|out.format= sample format to use with fixed settings\n"
440    "                valid values: s8, s16, s32, u8, u16, u32\n"
441    "                in|out.voices= number of voices to use\n"
442    "                in|out.buffer-len= length of buffer in microseconds\n"
443    "-audiodev none,id=id,[,prop[=value][,...]]\n"
444    "                dummy driver that discards all output\n"
445#ifdef CONFIG_AUDIO_ALSA
446    "-audiodev alsa,id=id[,prop[=value][,...]]\n"
447    "                in|out.dev= name of the audio device to use\n"
448    "                in|out.period-len= length of period in microseconds\n"
449    "                in|out.try-poll= attempt to use poll mode\n"
450    "                threshold= threshold (in microseconds) when playback starts\n"
451#endif
452#ifdef CONFIG_AUDIO_COREAUDIO
453    "-audiodev coreaudio,id=id[,prop[=value][,...]]\n"
454    "                in|out.buffer-count= number of buffers\n"
455#endif
456#ifdef CONFIG_AUDIO_DSOUND
457    "-audiodev dsound,id=id[,prop[=value][,...]]\n"
458    "                latency= add extra latency to playback in microseconds\n"
459#endif
460#ifdef CONFIG_AUDIO_OSS
461    "-audiodev oss,id=id[,prop[=value][,...]]\n"
462    "                in|out.dev= path of the audio device to use\n"
463    "                in|out.buffer-count= number of buffers\n"
464    "                in|out.try-poll= attempt to use poll mode\n"
465    "                try-mmap= try using memory mapped access\n"
466    "                exclusive= open device in exclusive mode\n"
467    "                dsp-policy= set timing policy (0..10), -1 to use fragment mode\n"
468#endif
469#ifdef CONFIG_AUDIO_PA
470    "-audiodev pa,id=id[,prop[=value][,...]]\n"
471    "                server= PulseAudio server address\n"
472    "                in|out.name= source/sink device name\n"
473#endif
474#ifdef CONFIG_AUDIO_SDL
475    "-audiodev sdl,id=id[,prop[=value][,...]]\n"
476#endif
477#ifdef CONFIG_SPICE
478    "-audiodev spice,id=id[,prop[=value][,...]]\n"
479#endif
480    "-audiodev wav,id=id[,prop[=value][,...]]\n"
481    "                path= path of wav file to record\n",
482    QEMU_ARCH_ALL)
483STEXI
484@item -audiodev [driver=]@var{driver},id=@var{id}[,@var{prop}[=@var{value}][,...]]
485@findex -audiodev
486Adds a new audio backend @var{driver} identified by @var{id}.  There are
487global and driver specific properties.  Some values can be set
488differently for input and output, they're marked with @code{in|out.}.
489You can set the input's property with @code{in.@var{prop}} and the
490output's property with @code{out.@var{prop}}. For example:
491@example
492-audiodev alsa,id=example,in.frequency=44110,out.frequency=8000
493-audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified
494@end example
495
496Valid global options are:
497
498@table @option
499@item id=@var{identifier}
500Identifies the audio backend.
501
502@item timer-period=@var{period}
503Sets the timer @var{period} used by the audio subsystem in microseconds.
504Default is 10000 (10 ms).
505
506@item in|out.fixed-settings=on|off
507Use fixed settings for host audio.  When off, it will change based on
508how the guest opens the sound card.  In this case you must not specify
509@var{frequency}, @var{channels} or @var{format}.  Default is on.
510
511@item in|out.frequency=@var{frequency}
512Specify the @var{frequency} to use when using @var{fixed-settings}.
513Default is 44100Hz.
514
515@item in|out.channels=@var{channels}
516Specify the number of @var{channels} to use when using
517@var{fixed-settings}. Default is 2 (stereo).
518
519@item in|out.format=@var{format}
520Specify the sample @var{format} to use when using @var{fixed-settings}.
521Valid values are: @code{s8}, @code{s16}, @code{s32}, @code{u8},
522@code{u16}, @code{u32}. Default is @code{s16}.
523
524@item in|out.voices=@var{voices}
525Specify the number of @var{voices} to use.  Default is 1.
526
527@item in|out.buffer=@var{usecs}
528Sets the size of the buffer in microseconds.
529
530@end table
531
532@item -audiodev none,id=@var{id}[,@var{prop}[=@var{value}][,...]]
533Creates a dummy backend that discards all outputs.  This backend has no
534backend specific properties.
535
536@item -audiodev alsa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
537Creates backend using the ALSA.  This backend is only available on
538Linux.
539
540ALSA specific options are:
541
542@table @option
543
544@item in|out.dev=@var{device}
545Specify the ALSA @var{device} to use for input and/or output.  Default
546is @code{default}.
547
548@item in|out.period-len=@var{usecs}
549Sets the period length in microseconds.
550
551@item in|out.try-poll=on|off
552Attempt to use poll mode with the device.  Default is on.
553
554@item threshold=@var{threshold}
555Threshold (in microseconds) when playback starts.  Default is 0.
556
557@end table
558
559@item -audiodev coreaudio,id=@var{id}[,@var{prop}[=@var{value}][,...]]
560Creates a backend using Apple's Core Audio.  This backend is only
561available on Mac OS and only supports playback.
562
563Core Audio specific options are:
564
565@table @option
566
567@item in|out.buffer-count=@var{count}
568Sets the @var{count} of the buffers.
569
570@end table
571
572@item -audiodev dsound,id=@var{id}[,@var{prop}[=@var{value}][,...]]
573Creates a backend using Microsoft's DirectSound.  This backend is only
574available on Windows and only supports playback.
575
576DirectSound specific options are:
577
578@table @option
579
580@item latency=@var{usecs}
581Add extra @var{usecs} microseconds latency to playback.  Default is
58210000 (10 ms).
583
584@end table
585
586@item -audiodev oss,id=@var{id}[,@var{prop}[=@var{value}][,...]]
587Creates a backend using OSS.  This backend is available on most
588Unix-like systems.
589
590OSS specific options are:
591
592@table @option
593
594@item in|out.dev=@var{device}
595Specify the file name of the OSS @var{device} to use.  Default is
596@code{/dev/dsp}.
597
598@item in|out.buffer-count=@var{count}
599Sets the @var{count} of the buffers.
600
601@item in|out.try-poll=on|of
602Attempt to use poll mode with the device.  Default is on.
603
604@item try-mmap=on|off
605Try using memory mapped device access.  Default is off.
606
607@item exclusive=on|off
608Open the device in exclusive mode (vmix won't work in this case).
609Default is off.
610
611@item dsp-policy=@var{policy}
612Sets the timing policy (between 0 and 10, where smaller number means
613smaller latency but higher CPU usage).  Use -1 to use buffer sizes
614specified by @code{buffer} and @code{buffer-count}.  This option is
615ignored if you do not have OSS 4. Default is 5.
616
617@end table
618
619@item -audiodev pa,id=@var{id}[,@var{prop}[=@var{value}][,...]]
620Creates a backend using PulseAudio.  This backend is available on most
621systems.
622
623PulseAudio specific options are:
624
625@table @option
626
627@item server=@var{server}
628Sets the PulseAudio @var{server} to connect to.
629
630@item in|out.name=@var{sink}
631Use the specified source/sink for recording/playback.
632
633@end table
634
635@item -audiodev sdl,id=@var{id}[,@var{prop}[=@var{value}][,...]]
636Creates a backend using SDL.  This backend is available on most systems,
637but you should use your platform's native backend if possible.  This
638backend has no backend specific properties.
639
640@item -audiodev spice,id=@var{id}[,@var{prop}[=@var{value}][,...]]
641Creates a backend that sends audio through SPICE.  This backend requires
642@code{-spice} and automatically selected in that case, so usually you
643can ignore this option.  This backend has no backend specific
644properties.
645
646@item -audiodev wav,id=@var{id}[,@var{prop}[=@var{value}][,...]]
647Creates a backend that writes audio to a WAV file.
648
649Backend specific options are:
650
651@table @option
652
653@item path=@var{path}
654Write recorded audio into the specified file.  Default is
655@code{qemu.wav}.
656
657@end table
658ETEXI
659
660DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
661    "-soundhw c1,... enable audio support\n"
662    "                and only specified sound cards (comma separated list)\n"
663    "                use '-soundhw help' to get the list of supported cards\n"
664    "                use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
665STEXI
666@item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
667@findex -soundhw
668Enable audio and selected sound hardware. Use 'help' to print all
669available sound hardware.
670
671@example
672qemu-system-i386 -soundhw sb16,adlib disk.img
673qemu-system-i386 -soundhw es1370 disk.img
674qemu-system-i386 -soundhw ac97 disk.img
675qemu-system-i386 -soundhw hda disk.img
676qemu-system-i386 -soundhw all disk.img
677qemu-system-i386 -soundhw help
678@end example
679
680Note that Linux's i810_audio OSS kernel (for AC97) module might
681require manually specifying clocking.
682
683@example
684modprobe i810_audio clocking=48000
685@end example
686ETEXI
687
688DEF("device", HAS_ARG, QEMU_OPTION_device,
689    "-device driver[,prop[=value][,...]]\n"
690    "                add device (based on driver)\n"
691    "                prop=value,... sets driver properties\n"
692    "                use '-device help' to print all possible drivers\n"
693    "                use '-device driver,help' to print all possible properties\n",
694    QEMU_ARCH_ALL)
695STEXI
696@item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
697@findex -device
698Add device @var{driver}.  @var{prop}=@var{value} sets driver
699properties.  Valid properties depend on the driver.  To get help on
700possible drivers and properties, use @code{-device help} and
701@code{-device @var{driver},help}.
702
703Some drivers are:
704@item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}]
705
706Add an IPMI BMC.  This is a simulation of a hardware management
707interface processor that normally sits on a system.  It provides
708a watchdog and the ability to reset and power control the system.
709You need to connect this to an IPMI interface to make it useful
710
711The IPMI slave address to use for the BMC.  The default is 0x20.
712This address is the BMC's address on the I2C network of management
713controllers.  If you don't know what this means, it is safe to ignore
714it.
715
716@table @option
717@item bmc=@var{id}
718The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
719@item slave_addr=@var{val}
720Define slave address to use for the BMC.  The default is 0x20.
721@item sdrfile=@var{file}
722file containing raw Sensor Data Records (SDR) data. The default is none.
723@item fruareasize=@var{val}
724size of a Field Replaceable Unit (FRU) area.  The default is 1024.
725@item frudatafile=@var{file}
726file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
727@end table
728
729@item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
730
731Add a connection to an external IPMI BMC simulator.  Instead of
732locally emulating the BMC like the above item, instead connect
733to an external entity that provides the IPMI services.
734
735A connection is made to an external BMC simulator.  If you do this, it
736is strongly recommended that you use the "reconnect=" chardev option
737to reconnect to the simulator if the connection is lost.  Note that if
738this is not used carefully, it can be a security issue, as the
739interface has the ability to send resets, NMIs, and power off the VM.
740It's best if QEMU makes a connection to an external simulator running
741on a secure port on localhost, so neither the simulator nor QEMU is
742exposed to any outside network.
743
744See the "lanserv/README.vm" file in the OpenIPMI library for more
745details on the external interface.
746
747@item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
748
749Add a KCS IPMI interafce on the ISA bus.  This also adds a
750corresponding ACPI and SMBIOS entries, if appropriate.
751
752@table @option
753@item bmc=@var{id}
754The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
755@item ioport=@var{val}
756Define the I/O address of the interface.  The default is 0xca0 for KCS.
757@item irq=@var{val}
758Define the interrupt to use.  The default is 5.  To disable interrupts,
759set this to 0.
760@end table
761
762@item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
763
764Like the KCS interface, but defines a BT interface.  The default port is
7650xe4 and the default interrupt is 5.
766
767ETEXI
768
769DEF("name", HAS_ARG, QEMU_OPTION_name,
770    "-name string1[,process=string2][,debug-threads=on|off]\n"
771    "                set the name of the guest\n"
772    "                string1 sets the window title and string2 the process name\n"
773    "                When debug-threads is enabled, individual threads are given a separate name\n"
774    "                NOTE: The thread names are for debugging and not a stable API.\n",
775    QEMU_ARCH_ALL)
776STEXI
777@item -name @var{name}
778@findex -name
779Sets the @var{name} of the guest.
780This name will be displayed in the SDL window caption.
781The @var{name} will also be used for the VNC server.
782Also optionally set the top visible process name in Linux.
783Naming of individual threads can also be enabled on Linux to aid debugging.
784ETEXI
785
786DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
787    "-uuid %08x-%04x-%04x-%04x-%012x\n"
788    "                specify machine UUID\n", QEMU_ARCH_ALL)
789STEXI
790@item -uuid @var{uuid}
791@findex -uuid
792Set system UUID.
793ETEXI
794
795STEXI
796@end table
797ETEXI
798DEFHEADING()
799
800DEFHEADING(Block device options:)
801STEXI
802@table @option
803ETEXI
804
805DEF("fda", HAS_ARG, QEMU_OPTION_fda,
806    "-fda/-fdb file  use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
807DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
808STEXI
809@item -fda @var{file}
810@itemx -fdb @var{file}
811@findex -fda
812@findex -fdb
813Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
814ETEXI
815
816DEF("hda", HAS_ARG, QEMU_OPTION_hda,
817    "-hda/-hdb file  use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
818DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
819DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
820    "-hdc/-hdd file  use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
821DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
822STEXI
823@item -hda @var{file}
824@itemx -hdb @var{file}
825@itemx -hdc @var{file}
826@itemx -hdd @var{file}
827@findex -hda
828@findex -hdb
829@findex -hdc
830@findex -hdd
831Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
832ETEXI
833
834DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
835    "-cdrom file     use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
836    QEMU_ARCH_ALL)
837STEXI
838@item -cdrom @var{file}
839@findex -cdrom
840Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
841@option{-cdrom} at the same time). You can use the host CD-ROM by
842using @file{/dev/cdrom} as filename (@pxref{host_drives}).
843ETEXI
844
845DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
846    "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
847    "          [,cache.direct=on|off][,cache.no-flush=on|off]\n"
848    "          [,read-only=on|off][,detect-zeroes=on|off|unmap]\n"
849    "          [,driver specific parameters...]\n"
850    "                configure a block backend\n", QEMU_ARCH_ALL)
851STEXI
852@item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
853@findex -blockdev
854
855Define a new block driver node. Some of the options apply to all block drivers,
856other options are only accepted for a specific block driver. See below for a
857list of generic options and options for the most common block drivers.
858
859Options that expect a reference to another node (e.g. @code{file}) can be
860given in two ways. Either you specify the node name of an already existing node
861(file=@var{node-name}), or you define a new node inline, adding options
862for the referenced node after a dot (file.filename=@var{path},file.aio=native).
863
864A block driver node created with @option{-blockdev} can be used for a guest
865device by specifying its node name for the @code{drive} property in a
866@option{-device} argument that defines a block device.
867
868@table @option
869@item Valid options for any block driver node:
870
871@table @code
872@item driver
873Specifies the block driver to use for the given node.
874@item node-name
875This defines the name of the block driver node by which it will be referenced
876later. The name must be unique, i.e. it must not match the name of a different
877block driver node, or (if you use @option{-drive} as well) the ID of a drive.
878
879If no node name is specified, it is automatically generated. The generated node
880name is not intended to be predictable and changes between QEMU invocations.
881For the top level, an explicit node name must be specified.
882@item read-only
883Open the node read-only. Guest write attempts will fail.
884@item cache.direct
885The host page cache can be avoided with @option{cache.direct=on}. This will
886attempt to do disk IO directly to the guest's memory. QEMU may still perform an
887internal copy of the data.
888@item cache.no-flush
889In case you don't care about data integrity over host failures, you can use
890@option{cache.no-flush=on}. This option tells QEMU that it never needs to write
891any data to the disk but can instead keep things in cache. If anything goes
892wrong, like your host losing power, the disk storage getting disconnected
893accidentally, etc. your image will most probably be rendered unusable.
894@item discard=@var{discard}
895@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls
896whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are
897ignored or passed to the filesystem. Some machine types may not support
898discard requests.
899@item detect-zeroes=@var{detect-zeroes}
900@var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic
901conversion of plain zero writes by the OS to driver specific optimized
902zero write commands. You may even choose "unmap" if @var{discard} is set
903to "unmap" to allow a zero write to be converted to an @code{unmap} operation.
904@end table
905
906@item Driver-specific options for @code{file}
907
908This is the protocol-level block driver for accessing regular files.
909
910@table @code
911@item filename
912The path to the image file in the local filesystem
913@item aio
914Specifies the AIO backend (threads/native, default: threads)
915@item locking
916Specifies whether the image file is protected with Linux OFD / POSIX locks. The
917default is to use the Linux Open File Descriptor API if available, otherwise no
918lock is applied.  (auto/on/off, default: auto)
919@end table
920Example:
921@example
922-blockdev driver=file,node-name=disk,filename=disk.img
923@end example
924
925@item Driver-specific options for @code{raw}
926
927This is the image format block driver for raw images. It is usually
928stacked on top of a protocol level block driver such as @code{file}.
929
930@table @code
931@item file
932Reference to or definition of the data source block driver node
933(e.g. a @code{file} driver node)
934@end table
935Example 1:
936@example
937-blockdev driver=file,node-name=disk_file,filename=disk.img
938-blockdev driver=raw,node-name=disk,file=disk_file
939@end example
940Example 2:
941@example
942-blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
943@end example
944
945@item Driver-specific options for @code{qcow2}
946
947This is the image format block driver for qcow2 images. It is usually
948stacked on top of a protocol level block driver such as @code{file}.
949
950@table @code
951@item file
952Reference to or definition of the data source block driver node
953(e.g. a @code{file} driver node)
954
955@item backing
956Reference to or definition of the backing file block device (default is taken
957from the image file). It is allowed to pass @code{null} here in order to disable
958the default backing file.
959
960@item lazy-refcounts
961Whether to enable the lazy refcounts feature (on/off; default is taken from the
962image file)
963
964@item cache-size
965The maximum total size of the L2 table and refcount block caches in bytes
966(default: the sum of l2-cache-size and refcount-cache-size)
967
968@item l2-cache-size
969The maximum size of the L2 table cache in bytes
970(default: if cache-size is not specified - 32M on Linux platforms, and 8M on
971non-Linux platforms; otherwise, as large as possible within the cache-size,
972while permitting the requested or the minimal refcount cache size)
973
974@item refcount-cache-size
975The maximum size of the refcount block cache in bytes
976(default: 4 times the cluster size; or if cache-size is specified, the part of
977it which is not used for the L2 cache)
978
979@item cache-clean-interval
980Clean unused entries in the L2 and refcount caches. The interval is in seconds.
981The default value is 600 on supporting platforms, and 0 on other platforms.
982Setting it to 0 disables this feature.
983
984@item pass-discard-request
985Whether discard requests to the qcow2 device should be forwarded to the data
986source (on/off; default: on if discard=unmap is specified, off otherwise)
987
988@item pass-discard-snapshot
989Whether discard requests for the data source should be issued when a snapshot
990operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off;
991default: on)
992
993@item pass-discard-other
994Whether discard requests for the data source should be issued on other
995occasions where a cluster gets freed (on/off; default: off)
996
997@item overlap-check
998Which overlap checks to perform for writes to the image
999(none/constant/cached/all; default: cached). For details or finer
1000granularity control refer to the QAPI documentation of @code{blockdev-add}.
1001@end table
1002
1003Example 1:
1004@example
1005-blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
1006-blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
1007@end example
1008Example 2:
1009@example
1010-blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
1011@end example
1012
1013@item Driver-specific options for other drivers
1014Please refer to the QAPI documentation of the @code{blockdev-add} QMP command.
1015
1016@end table
1017
1018ETEXI
1019
1020DEF("drive", HAS_ARG, QEMU_OPTION_drive,
1021    "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
1022    "       [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
1023    "       [,snapshot=on|off][,rerror=ignore|stop|report]\n"
1024    "       [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n"
1025    "       [,readonly=on|off][,copy-on-read=on|off]\n"
1026    "       [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
1027    "       [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
1028    "       [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
1029    "       [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
1030    "       [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
1031    "       [[,iops_size=is]]\n"
1032    "       [[,group=g]]\n"
1033    "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
1034STEXI
1035@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
1036@findex -drive
1037
1038Define a new drive. This includes creating a block driver node (the backend) as
1039well as a guest device, and is mostly a shortcut for defining the corresponding
1040@option{-blockdev} and @option{-device} options.
1041
1042@option{-drive} accepts all options that are accepted by @option{-blockdev}. In
1043addition, it knows the following options:
1044
1045@table @option
1046@item file=@var{file}
1047This option defines which disk image (@pxref{disk_images}) to use with
1048this drive. If the filename contains comma, you must double it
1049(for instance, "file=my,,file" to use file "my,file").
1050
1051Special files such as iSCSI devices can be specified using protocol
1052specific URLs. See the section for "Device URL Syntax" for more information.
1053@item if=@var{interface}
1054This option defines on which type on interface the drive is connected.
1055Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none.
1056@item bus=@var{bus},unit=@var{unit}
1057These options define where is connected the drive by defining the bus number and
1058the unit id.
1059@item index=@var{index}
1060This option defines where is connected the drive by using an index in the list
1061of available connectors of a given interface type.
1062@item media=@var{media}
1063This option defines the type of the media: disk or cdrom.
1064@item snapshot=@var{snapshot}
1065@var{snapshot} is "on" or "off" and controls snapshot mode for the given drive
1066(see @option{-snapshot}).
1067@item cache=@var{cache}
1068@var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough"
1069and controls how the host cache is used to access block data. This is a
1070shortcut that sets the @option{cache.direct} and @option{cache.no-flush}
1071options (as in @option{-blockdev}), and additionally @option{cache.writeback},
1072which provides a default for the @option{write-cache} option of block guest
1073devices (as in @option{-device}). The modes correspond to the following
1074settings:
1075
1076@c Our texi2pod.pl script doesn't support @multitable, so fall back to using
1077@c plain ASCII art (well, UTF-8 art really). This looks okay both in the manpage
1078@c and the HTML output.
1079@example
1080@             │ cache.writeback   cache.direct   cache.no-flush
1081─────────────┼─────────────────────────────────────────────────
1082writeback    │ on                off            off
1083none         │ on                on             off
1084writethrough │ off               off            off
1085directsync   │ off               on             off
1086unsafe       │ on                off            on
1087@end example
1088
1089The default mode is @option{cache=writeback}.
1090
1091@item aio=@var{aio}
1092@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
1093@item format=@var{format}
1094Specify which disk @var{format} will be used rather than detecting
1095the format.  Can be used to specify format=raw to avoid interpreting
1096an untrusted format header.
1097@item werror=@var{action},rerror=@var{action}
1098Specify which @var{action} to take on write and read errors. Valid actions are:
1099"ignore" (ignore the error and try to continue), "stop" (pause QEMU),
1100"report" (report the error to the guest), "enospc" (pause QEMU only if the
1101host disk is full; report the error to the guest otherwise).
1102The default setting is @option{werror=enospc} and @option{rerror=report}.
1103@item copy-on-read=@var{copy-on-read}
1104@var{copy-on-read} is "on" or "off" and enables whether to copy read backing
1105file sectors into the image file.
1106@item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
1107Specify bandwidth throttling limits in bytes per second, either for all request
1108types or for reads or writes only.  Small values can lead to timeouts or hangs
1109inside the guest.  A safe minimum for disks is 2 MB/s.
1110@item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm}
1111Specify bursts in bytes per second, either for all request types or for reads
1112or writes only.  Bursts allow the guest I/O to spike above the limit
1113temporarily.
1114@item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
1115Specify request rate limits in requests per second, either for all request
1116types or for reads or writes only.
1117@item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
1118Specify bursts in requests per second, either for all request types or for reads
1119or writes only.  Bursts allow the guest I/O to spike above the limit
1120temporarily.
1121@item iops_size=@var{is}
1122Let every @var{is} bytes of a request count as a new request for iops
1123throttling purposes.  Use this option to prevent guests from circumventing iops
1124limits by sending fewer but larger requests.
1125@item group=@var{g}
1126Join a throttling quota group with given name @var{g}.  All drives that are
1127members of the same group are accounted for together.  Use this option to
1128prevent guests from circumventing throttling limits by using many small disks
1129instead of a single larger disk.
1130@end table
1131
1132By default, the @option{cache.writeback=on} mode is used. It will report data
1133writes as completed as soon as the data is present in the host page cache.
1134This is safe as long as your guest OS makes sure to correctly flush disk caches
1135where needed. If your guest OS does not handle volatile disk write caches
1136correctly and your host crashes or loses power, then the guest may experience
1137data corruption.
1138
1139For such guests, you should consider using @option{cache.writeback=off}. This
1140means that the host page cache will be used to read and write data, but write
1141notification will be sent to the guest only after QEMU has made sure to flush
1142each write to the disk. Be aware that this has a major impact on performance.
1143
1144When using the @option{-snapshot} option, unsafe caching is always used.
1145
1146Copy-on-read avoids accessing the same backing file sectors repeatedly and is
1147useful when the backing file is over a slow network.  By default copy-on-read
1148is off.
1149
1150Instead of @option{-cdrom} you can use:
1151@example
1152qemu-system-i386 -drive file=file,index=2,media=cdrom
1153@end example
1154
1155Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
1156use:
1157@example
1158qemu-system-i386 -drive file=file,index=0,media=disk
1159qemu-system-i386 -drive file=file,index=1,media=disk
1160qemu-system-i386 -drive file=file,index=2,media=disk
1161qemu-system-i386 -drive file=file,index=3,media=disk
1162@end example
1163
1164You can open an image using pre-opened file descriptors from an fd set:
1165@example
1166qemu-system-i386
1167-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
1168-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
1169-drive file=/dev/fdset/2,index=0,media=disk
1170@end example
1171
1172You can connect a CDROM to the slave of ide0:
1173@example
1174qemu-system-i386 -drive file=file,if=ide,index=1,media=cdrom
1175@end example
1176
1177If you don't specify the "file=" argument, you define an empty drive:
1178@example
1179qemu-system-i386 -drive if=ide,index=1,media=cdrom
1180@end example
1181
1182Instead of @option{-fda}, @option{-fdb}, you can use:
1183@example
1184qemu-system-i386 -drive file=file,index=0,if=floppy
1185qemu-system-i386 -drive file=file,index=1,if=floppy
1186@end example
1187
1188By default, @var{interface} is "ide" and @var{index} is automatically
1189incremented:
1190@example
1191qemu-system-i386 -drive file=a -drive file=b"
1192@end example
1193is interpreted like:
1194@example
1195qemu-system-i386 -hda a -hdb b
1196@end example
1197ETEXI
1198
1199DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
1200    "-mtdblock file  use 'file' as on-board Flash memory image\n",
1201    QEMU_ARCH_ALL)
1202STEXI
1203@item -mtdblock @var{file}
1204@findex -mtdblock
1205Use @var{file} as on-board Flash memory image.
1206ETEXI
1207
1208DEF("sd", HAS_ARG, QEMU_OPTION_sd,
1209    "-sd file        use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
1210STEXI
1211@item -sd @var{file}
1212@findex -sd
1213Use @var{file} as SecureDigital card image.
1214ETEXI
1215
1216DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
1217    "-pflash file    use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
1218STEXI
1219@item -pflash @var{file}
1220@findex -pflash
1221Use @var{file} as a parallel flash image.
1222ETEXI
1223
1224DEF("snapshot", 0, QEMU_OPTION_snapshot,
1225    "-snapshot       write to temporary files instead of disk image files\n",
1226    QEMU_ARCH_ALL)
1227STEXI
1228@item -snapshot
1229@findex -snapshot
1230Write to temporary files instead of disk image files. In this case,
1231the raw disk image you use is not written back. You can however force
1232the write back by pressing @key{C-a s} (@pxref{disk_images}).
1233ETEXI
1234
1235DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1236    "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1237    " [,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n"
1238    " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1239    " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1240    " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1241    " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1242    " [[,throttling.iops-size=is]]\n"
1243    "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly]\n"
1244    "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly]\n"
1245    "-fsdev synth,id=id\n",
1246    QEMU_ARCH_ALL)
1247
1248STEXI
1249
1250@item -fsdev local,id=@var{id},path=@var{path},security_model=@var{security_model} [,writeout=@var{writeout}][,readonly][,fmode=@var{fmode}][,dmode=@var{dmode}] [,throttling.@var{option}=@var{value}[,throttling.@var{option}=@var{value}[,...]]]
1251@itemx -fsdev proxy,id=@var{id},socket=@var{socket}[,writeout=@var{writeout}][,readonly]
1252@itemx -fsdev proxy,id=@var{id},sock_fd=@var{sock_fd}[,writeout=@var{writeout}][,readonly]
1253@itemx -fsdev synth,id=@var{id}[,readonly]
1254@findex -fsdev
1255Define a new file system device. Valid options are:
1256@table @option
1257@item local
1258Accesses to the filesystem are done by QEMU.
1259@item proxy
1260Accesses to the filesystem are done by virtfs-proxy-helper(1).
1261@item synth
1262Synthetic filesystem, only used by QTests.
1263@item id=@var{id}
1264Specifies identifier for this device.
1265@item path=@var{path}
1266Specifies the export path for the file system device. Files under
1267this path will be available to the 9p client on the guest.
1268@item security_model=@var{security_model}
1269Specifies the security model to be used for this export path.
1270Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1271In "passthrough" security model, files are stored using the same
1272credentials as they are created on the guest. This requires QEMU
1273to run as root. In "mapped-xattr" security model, some of the file
1274attributes like uid, gid, mode bits and link target are stored as
1275file attributes. For "mapped-file" these attributes are stored in the
1276hidden .virtfs_metadata directory. Directories exported by this security model cannot
1277interact with other unix tools. "none" security model is same as
1278passthrough except the sever won't report failures if it fails to
1279set file attributes like ownership. Security model is mandatory
1280only for local fsdriver. Other fsdrivers (like proxy) don't take
1281security model as a parameter.
1282@item writeout=@var{writeout}
1283This is an optional argument. The only supported value is "immediate".
1284This means that host page cache will be used to read and write data but
1285write notification will be sent to the guest only when the data has been
1286reported as written by the storage subsystem.
1287@item readonly
1288Enables exporting 9p share as a readonly mount for guests. By default
1289read-write access is given.
1290@item socket=@var{socket}
1291Enables proxy filesystem driver to use passed socket file for communicating
1292with virtfs-proxy-helper(1).
1293@item sock_fd=@var{sock_fd}
1294Enables proxy filesystem driver to use passed socket descriptor for
1295communicating with virtfs-proxy-helper(1). Usually a helper like libvirt
1296will create socketpair and pass one of the fds as sock_fd.
1297@item fmode=@var{fmode}
1298Specifies the default mode for newly created files on the host. Works only
1299with security models "mapped-xattr" and "mapped-file".
1300@item dmode=@var{dmode}
1301Specifies the default mode for newly created directories on the host. Works
1302only with security models "mapped-xattr" and "mapped-file".
1303@item throttling.bps-total=@var{b},throttling.bps-read=@var{r},throttling.bps-write=@var{w}
1304Specify bandwidth throttling limits in bytes per second, either for all request
1305types or for reads or writes only.
1306@item throttling.bps-total-max=@var{bm},bps-read-max=@var{rm},bps-write-max=@var{wm}
1307Specify bursts in bytes per second, either for all request types or for reads
1308or writes only.  Bursts allow the guest I/O to spike above the limit
1309temporarily.
1310@item throttling.iops-total=@var{i},throttling.iops-read=@var{r}, throttling.iops-write=@var{w}
1311Specify request rate limits in requests per second, either for all request
1312types or for reads or writes only.
1313@item throttling.iops-total-max=@var{im},throttling.iops-read-max=@var{irm}, throttling.iops-write-max=@var{iwm}
1314Specify bursts in requests per second, either for all request types or for reads
1315or writes only.  Bursts allow the guest I/O to spike above the limit temporarily.
1316@item throttling.iops-size=@var{is}
1317Let every @var{is} bytes of a request count as a new request for iops
1318throttling purposes.
1319@end table
1320
1321-fsdev option is used along with -device driver "virtio-9p-...".
1322@item -device virtio-9p-@var{type},fsdev=@var{id},mount_tag=@var{mount_tag}
1323Options for virtio-9p-... driver are:
1324@table @option
1325@item @var{type}
1326Specifies the variant to be used. Supported values are "pci", "ccw" or "device",
1327depending on the machine type.
1328@item fsdev=@var{id}
1329Specifies the id value specified along with -fsdev option.
1330@item mount_tag=@var{mount_tag}
1331Specifies the tag name to be used by the guest to mount this export point.
1332@end table
1333
1334ETEXI
1335
1336DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1337    "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n"
1338    "        [,id=id][,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n"
1339    "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly]\n"
1340    "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly]\n"
1341    "-virtfs synth,mount_tag=tag[,id=id][,readonly]\n",
1342    QEMU_ARCH_ALL)
1343
1344STEXI
1345
1346@item -virtfs local,path=@var{path},mount_tag=@var{mount_tag} ,security_model=@var{security_model}[,writeout=@var{writeout}][,readonly] [,fmode=@var{fmode}][,dmode=@var{dmode}]
1347@itemx -virtfs proxy,socket=@var{socket},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly]
1348@itemx -virtfs proxy,sock_fd=@var{sock_fd},mount_tag=@var{mount_tag} [,writeout=@var{writeout}][,readonly]
1349@itemx -virtfs synth,mount_tag=@var{mount_tag}
1350@findex -virtfs
1351
1352Define a new filesystem device and expose it to the guest using a virtio-9p-device. The general form of a Virtual File system pass-through options are:
1353@table @option
1354@item local
1355Accesses to the filesystem are done by QEMU.
1356@item proxy
1357Accesses to the filesystem are done by virtfs-proxy-helper(1).
1358@item synth
1359Synthetic filesystem, only used by QTests.
1360@item id=@var{id}
1361Specifies identifier for the filesystem device
1362@item path=@var{path}
1363Specifies the export path for the file system device. Files under
1364this path will be available to the 9p client on the guest.
1365@item security_model=@var{security_model}
1366Specifies the security model to be used for this export path.
1367Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1368In "passthrough" security model, files are stored using the same
1369credentials as they are created on the guest. This requires QEMU
1370to run as root. In "mapped-xattr" security model, some of the file
1371attributes like uid, gid, mode bits and link target are stored as
1372file attributes. For "mapped-file" these attributes are stored in the
1373hidden .virtfs_metadata directory. Directories exported by this security model cannot
1374interact with other unix tools. "none" security model is same as
1375passthrough except the sever won't report failures if it fails to
1376set file attributes like ownership. Security model is mandatory only
1377for local fsdriver. Other fsdrivers (like proxy) don't take security
1378model as a parameter.
1379@item writeout=@var{writeout}
1380This is an optional argument. The only supported value is "immediate".
1381This means that host page cache will be used to read and write data but
1382write notification will be sent to the guest only when the data has been
1383reported as written by the storage subsystem.
1384@item readonly
1385Enables exporting 9p share as a readonly mount for guests. By default
1386read-write access is given.
1387@item socket=@var{socket}
1388Enables proxy filesystem driver to use passed socket file for
1389communicating with virtfs-proxy-helper(1). Usually a helper like libvirt
1390will create socketpair and pass one of the fds as sock_fd.
1391@item sock_fd
1392Enables proxy filesystem driver to use passed 'sock_fd' as the socket
1393descriptor for interfacing with virtfs-proxy-helper(1).
1394@item fmode=@var{fmode}
1395Specifies the default mode for newly created files on the host. Works only
1396with security models "mapped-xattr" and "mapped-file".
1397@item dmode=@var{dmode}
1398Specifies the default mode for newly created directories on the host. Works
1399only with security models "mapped-xattr" and "mapped-file".
1400@item mount_tag=@var{mount_tag}
1401Specifies the tag name to be used by the guest to mount this export point.
1402@end table
1403ETEXI
1404
1405DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
1406    "-virtfs_synth Create synthetic file system image\n",
1407    QEMU_ARCH_ALL)
1408STEXI
1409@item -virtfs_synth
1410@findex -virtfs_synth
1411Create synthetic file system image. Note that this option is now deprecated.
1412Please use @code{-fsdev synth} and @code{-device virtio-9p-...} instead.
1413ETEXI
1414
1415DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1416    "-iscsi [user=user][,password=password]\n"
1417    "       [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1418    "       [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1419    "       [,timeout=timeout]\n"
1420    "                iSCSI session parameters\n", QEMU_ARCH_ALL)
1421
1422STEXI
1423@item -iscsi
1424@findex -iscsi
1425Configure iSCSI session parameters.
1426ETEXI
1427
1428STEXI
1429@end table
1430ETEXI
1431DEFHEADING()
1432
1433DEFHEADING(USB options:)
1434STEXI
1435@table @option
1436ETEXI
1437
1438DEF("usb", 0, QEMU_OPTION_usb,
1439    "-usb            enable the USB driver (if it is not used by default yet)\n",
1440    QEMU_ARCH_ALL)
1441STEXI
1442@item -usb
1443@findex -usb
1444Enable the USB driver (if it is not used by default yet).
1445ETEXI
1446
1447DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1448    "-usbdevice name add the host or guest USB device 'name'\n",
1449    QEMU_ARCH_ALL)
1450STEXI
1451
1452@item -usbdevice @var{devname}
1453@findex -usbdevice
1454Add the USB device @var{devname}. Note that this option is deprecated,
1455please use @code{-device usb-...} instead. @xref{usb_devices}.
1456
1457@table @option
1458
1459@item mouse
1460Virtual Mouse. This will override the PS/2 mouse emulation when activated.
1461
1462@item tablet
1463Pointer device that uses absolute coordinates (like a touchscreen). This
1464means QEMU is able to report the mouse position without having to grab the
1465mouse. Also overrides the PS/2 mouse emulation when activated.
1466
1467@item braille
1468Braille device.  This will use BrlAPI to display the braille output on a real
1469or fake device.
1470
1471@end table
1472ETEXI
1473
1474STEXI
1475@end table
1476ETEXI
1477DEFHEADING()
1478
1479DEFHEADING(Display options:)
1480STEXI
1481@table @option
1482ETEXI
1483
1484DEF("display", HAS_ARG, QEMU_OPTION_display,
1485    "-display spice-app[,gl=on|off]\n"
1486    "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
1487    "            [,window_close=on|off][,gl=on|core|es|off]\n"
1488    "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1489    "-display vnc=<display>[,<optargs>]\n"
1490    "-display curses[,charset=<encoding>]\n"
1491    "-display none\n"
1492    "-display egl-headless[,rendernode=<file>]"
1493    "                select display type\n"
1494    "The default display is equivalent to\n"
1495#if defined(CONFIG_GTK)
1496            "\t\"-display gtk\"\n"
1497#elif defined(CONFIG_SDL)
1498            "\t\"-display sdl\"\n"
1499#elif defined(CONFIG_COCOA)
1500            "\t\"-display cocoa\"\n"
1501#elif defined(CONFIG_VNC)
1502            "\t\"-vnc localhost:0,to=99,id=default\"\n"
1503#else
1504            "\t\"-display none\"\n"
1505#endif
1506    , QEMU_ARCH_ALL)
1507STEXI
1508@item -display @var{type}
1509@findex -display
1510Select type of display to use. This option is a replacement for the
1511old style -sdl/-curses/... options. Valid values for @var{type} are
1512@table @option
1513@item sdl
1514Display video output via SDL (usually in a separate graphics
1515window; see the SDL documentation for other possibilities).
1516@item curses
1517Display video output via curses. For graphics device models which
1518support a text mode, QEMU can display this output using a
1519curses/ncurses interface. Nothing is displayed when the graphics
1520device is in graphical mode or if the graphics device does not support
1521a text mode. Generally only the VGA device models support text mode.
1522The font charset used by the guest can be specified with the
1523@code{charset} option, for example @code{charset=CP850} for IBM CP850
1524encoding. The default is @code{CP437}.
1525@item none
1526Do not display video output. The guest will still see an emulated
1527graphics card, but its output will not be displayed to the QEMU
1528user. This option differs from the -nographic option in that it
1529only affects what is done with video output; -nographic also changes
1530the destination of the serial and parallel port data.
1531@item gtk
1532Display video output in a GTK window. This interface provides drop-down
1533menus and other UI elements to configure and control the VM during
1534runtime.
1535@item vnc
1536Start a VNC server on display <arg>
1537@item egl-headless
1538Offload all OpenGL operations to a local DRI device. For any graphical display,
1539this display needs to be paired with either VNC or SPICE displays.
1540@item spice-app
1541Start QEMU as a Spice server and launch the default Spice client
1542application. The Spice server will redirect the serial consoles and
1543QEMU monitors. (Since 4.0)
1544@end table
1545ETEXI
1546
1547DEF("nographic", 0, QEMU_OPTION_nographic,
1548    "-nographic      disable graphical output and redirect serial I/Os to console\n",
1549    QEMU_ARCH_ALL)
1550STEXI
1551@item -nographic
1552@findex -nographic
1553Normally, if QEMU is compiled with graphical window support, it displays
1554output such as guest graphics, guest console, and the QEMU monitor in a
1555window. With this option, you can totally disable graphical output so
1556that QEMU is a simple command line application. The emulated serial port
1557is redirected on the console and muxed with the monitor (unless
1558redirected elsewhere explicitly). Therefore, you can still use QEMU to
1559debug a Linux kernel with a serial console. Use @key{C-a h} for help on
1560switching between the console and monitor.
1561ETEXI
1562
1563DEF("curses", 0, QEMU_OPTION_curses,
1564    "-curses         shorthand for -display curses\n",
1565    QEMU_ARCH_ALL)
1566STEXI
1567@item -curses
1568@findex -curses
1569Normally, if QEMU is compiled with graphical window support, it displays
1570output such as guest graphics, guest console, and the QEMU monitor in a
1571window. With this option, QEMU can display the VGA output when in text
1572mode using a curses/ncurses interface. Nothing is displayed in graphical
1573mode.
1574ETEXI
1575
1576DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1577    "-alt-grab       use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1578    QEMU_ARCH_ALL)
1579STEXI
1580@item -alt-grab
1581@findex -alt-grab
1582Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
1583affects the special keys (for fullscreen, monitor-mode switching, etc).
1584ETEXI
1585
1586DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1587    "-ctrl-grab      use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1588    QEMU_ARCH_ALL)
1589STEXI
1590@item -ctrl-grab
1591@findex -ctrl-grab
1592Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
1593affects the special keys (for fullscreen, monitor-mode switching, etc).
1594ETEXI
1595
1596DEF("no-quit", 0, QEMU_OPTION_no_quit,
1597    "-no-quit        disable SDL window close capability\n", QEMU_ARCH_ALL)
1598STEXI
1599@item -no-quit
1600@findex -no-quit
1601Disable SDL window close capability.
1602ETEXI
1603
1604DEF("sdl", 0, QEMU_OPTION_sdl,
1605    "-sdl            shorthand for -display sdl\n", QEMU_ARCH_ALL)
1606STEXI
1607@item -sdl
1608@findex -sdl
1609Enable SDL.
1610ETEXI
1611
1612DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1613    "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1614    "       [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1615    "       [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1616    "       [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n"
1617    "       [,tls-ciphers=<list>]\n"
1618    "       [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1619    "       [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1620    "       [,sasl][,password=<secret>][,disable-ticketing]\n"
1621    "       [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1622    "       [,jpeg-wan-compression=[auto|never|always]]\n"
1623    "       [,zlib-glz-wan-compression=[auto|never|always]]\n"
1624    "       [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
1625    "       [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
1626    "       [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1627    "       [,gl=[on|off]][,rendernode=<file>]\n"
1628    "   enable spice\n"
1629    "   at least one of {port, tls-port} is mandatory\n",
1630    QEMU_ARCH_ALL)
1631STEXI
1632@item -spice @var{option}[,@var{option}[,...]]
1633@findex -spice
1634Enable the spice remote desktop protocol. Valid options are
1635
1636@table @option
1637
1638@item port=<nr>
1639Set the TCP port spice is listening on for plaintext channels.
1640
1641@item addr=<addr>
1642Set the IP address spice is listening on.  Default is any address.
1643
1644@item ipv4
1645@itemx ipv6
1646@itemx unix
1647Force using the specified IP version.
1648
1649@item password=<secret>
1650Set the password you need to authenticate.
1651
1652@item sasl
1653Require that the client use SASL to authenticate with the spice.
1654The exact choice of authentication method used is controlled from the
1655system / user's SASL configuration file for the 'qemu' service. This
1656is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1657unprivileged user, an environment variable SASL_CONF_PATH can be used
1658to make it search alternate locations for the service config.
1659While some SASL auth methods can also provide data encryption (eg GSSAPI),
1660it is recommended that SASL always be combined with the 'tls' and
1661'x509' settings to enable use of SSL and server certificates. This
1662ensures a data encryption preventing compromise of authentication
1663credentials.
1664
1665@item disable-ticketing
1666Allow client connects without authentication.
1667
1668@item disable-copy-paste
1669Disable copy paste between the client and the guest.
1670
1671@item disable-agent-file-xfer
1672Disable spice-vdagent based file-xfer between the client and the guest.
1673
1674@item tls-port=<nr>
1675Set the TCP port spice is listening on for encrypted channels.
1676
1677@item x509-dir=<dir>
1678Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1679
1680@item x509-key-file=<file>
1681@itemx x509-key-password=<file>
1682@itemx x509-cert-file=<file>
1683@itemx x509-cacert-file=<file>
1684@itemx x509-dh-key-file=<file>
1685The x509 file names can also be configured individually.
1686
1687@item tls-ciphers=<list>
1688Specify which ciphers to use.
1689
1690@item tls-channel=[main|display|cursor|inputs|record|playback]
1691@itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1692Force specific channel to be used with or without TLS encryption.  The
1693options can be specified multiple times to configure multiple
1694channels.  The special name "default" can be used to set the default
1695mode.  For channels which are not explicitly forced into one mode the
1696spice client is allowed to pick tls/plaintext as he pleases.
1697
1698@item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1699Configure image compression (lossless).
1700Default is auto_glz.
1701
1702@item jpeg-wan-compression=[auto|never|always]
1703@itemx zlib-glz-wan-compression=[auto|never|always]
1704Configure wan image compression (lossy for slow links).
1705Default is auto.
1706
1707@item streaming-video=[off|all|filter]
1708Configure video stream detection.  Default is off.
1709
1710@item agent-mouse=[on|off]
1711Enable/disable passing mouse events via vdagent.  Default is on.
1712
1713@item playback-compression=[on|off]
1714Enable/disable audio stream compression (using celt 0.5.1).  Default is on.
1715
1716@item seamless-migration=[on|off]
1717Enable/disable spice seamless migration. Default is off.
1718
1719@item gl=[on|off]
1720Enable/disable OpenGL context. Default is off.
1721
1722@item rendernode=<file>
1723DRM render node for OpenGL rendering. If not specified, it will pick
1724the first available. (Since 2.9)
1725
1726@end table
1727ETEXI
1728
1729DEF("portrait", 0, QEMU_OPTION_portrait,
1730    "-portrait       rotate graphical output 90 deg left (only PXA LCD)\n",
1731    QEMU_ARCH_ALL)
1732STEXI
1733@item -portrait
1734@findex -portrait
1735Rotate graphical output 90 deg left (only PXA LCD).
1736ETEXI
1737
1738DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1739    "-rotate <deg>   rotate graphical output some deg left (only PXA LCD)\n",
1740    QEMU_ARCH_ALL)
1741STEXI
1742@item -rotate @var{deg}
1743@findex -rotate
1744Rotate graphical output some deg left (only PXA LCD).
1745ETEXI
1746
1747DEF("vga", HAS_ARG, QEMU_OPTION_vga,
1748    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
1749    "                select video card type\n", QEMU_ARCH_ALL)
1750STEXI
1751@item -vga @var{type}
1752@findex -vga
1753Select type of VGA card to emulate. Valid values for @var{type} are
1754@table @option
1755@item cirrus
1756Cirrus Logic GD5446 Video card. All Windows versions starting from
1757Windows 95 should recognize and use this graphic card. For optimal
1758performances, use 16 bit color depth in the guest and the host OS.
1759(This card was the default before QEMU 2.2)
1760@item std
1761Standard VGA card with Bochs VBE extensions.  If your guest OS
1762supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1763to use high resolution modes (>= 1280x1024x16) then you should use
1764this option. (This card is the default since QEMU 2.2)
1765@item vmware
1766VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1767recent XFree86/XOrg server or Windows guest with a driver for this
1768card.
1769@item qxl
1770QXL paravirtual graphic card.  It is VGA compatible (including VESA
17712.0 VBE support).  Works best with qxl guest drivers installed though.
1772Recommended choice when using the spice protocol.
1773@item tcx
1774(sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1775sun4m machines and offers both 8-bit and 24-bit colour depths at a
1776fixed resolution of 1024x768.
1777@item cg3
1778(sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1779for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1780resolutions aimed at people wishing to run older Solaris versions.
1781@item virtio
1782Virtio VGA card.
1783@item none
1784Disable VGA card.
1785@end table
1786ETEXI
1787
1788DEF("full-screen", 0, QEMU_OPTION_full_screen,
1789    "-full-screen    start in full screen\n", QEMU_ARCH_ALL)
1790STEXI
1791@item -full-screen
1792@findex -full-screen
1793Start in full screen.
1794ETEXI
1795
1796DEF("g", 1, QEMU_OPTION_g ,
1797    "-g WxH[xDEPTH]  Set the initial graphical resolution and depth\n",
1798    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
1799STEXI
1800@item -g @var{width}x@var{height}[x@var{depth}]
1801@findex -g
1802Set the initial graphical resolution and depth (PPC, SPARC only).
1803ETEXI
1804
1805DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1806    "-vnc <display>  shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1807STEXI
1808@item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1809@findex -vnc
1810Normally, if QEMU is compiled with graphical window support, it displays
1811output such as guest graphics, guest console, and the QEMU monitor in a
1812window. With this option, you can have QEMU listen on VNC display
1813@var{display} and redirect the VGA display over the VNC session. It is
1814very useful to enable the usb tablet device when using this option
1815(option @option{-device usb-tablet}). When using the VNC display, you
1816must use the @option{-k} parameter to set the keyboard layout if you are
1817not using en-us. Valid syntax for the @var{display} is
1818
1819@table @option
1820
1821@item to=@var{L}
1822
1823With this option, QEMU will try next available VNC @var{display}s, until the
1824number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1825available, e.g. port 5900+@var{display} is already used by another
1826application. By default, to=0.
1827
1828@item @var{host}:@var{d}
1829
1830TCP connections will only be allowed from @var{host} on display @var{d}.
1831By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1832be omitted in which case the server will accept connections from any host.
1833
1834@item unix:@var{path}
1835
1836Connections will be allowed over UNIX domain sockets where @var{path} is the
1837location of a unix socket to listen for connections on.
1838
1839@item none
1840
1841VNC is initialized but not started. The monitor @code{change} command
1842can be used to later start the VNC server.
1843
1844@end table
1845
1846Following the @var{display} value there may be one or more @var{option} flags
1847separated by commas. Valid options are
1848
1849@table @option
1850
1851@item reverse
1852
1853Connect to a listening VNC client via a ``reverse'' connection. The
1854client is specified by the @var{display}. For reverse network
1855connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
1856is a TCP port number, not a display number.
1857
1858@item websocket
1859
1860Opens an additional TCP listening port dedicated to VNC Websocket connections.
1861If a bare @var{websocket} option is given, the Websocket port is
18625700+@var{display}. An alternative port can be specified with the
1863syntax @code{websocket}=@var{port}.
1864
1865If @var{host} is specified connections will only be allowed from this host.
1866It is possible to control the websocket listen address independently, using
1867the syntax @code{websocket}=@var{host}:@var{port}.
1868
1869If no TLS credentials are provided, the websocket connection runs in
1870unencrypted mode. If TLS credentials are provided, the websocket connection
1871requires encrypted client connections.
1872
1873@item password
1874
1875Require that password based authentication is used for client connections.
1876
1877The password must be set separately using the @code{set_password} command in
1878the @ref{pcsys_monitor}. The syntax to change your password is:
1879@code{set_password <protocol> <password>} where <protocol> could be either
1880"vnc" or "spice".
1881
1882If you would like to change <protocol> password expiration, you should use
1883@code{expire_password <protocol> <expiration-time>} where expiration time could
1884be one of the following options: now, never, +seconds or UNIX time of
1885expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
1886to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
1887date and time).
1888
1889You can also use keywords "now" or "never" for the expiration time to
1890allow <protocol> password to expire immediately or never expire.
1891
1892@item tls-creds=@var{ID}
1893
1894Provides the ID of a set of TLS credentials to use to secure the
1895VNC server. They will apply to both the normal VNC server socket
1896and the websocket socket (if enabled). Setting TLS credentials
1897will cause the VNC server socket to enable the VeNCrypt auth
1898mechanism.  The credentials should have been previously created
1899using the @option{-object tls-creds} argument.
1900
1901@item tls-authz=@var{ID}
1902
1903Provides the ID of the QAuthZ authorization object against which
1904the client's x509 distinguished name will validated. This object is
1905only resolved at time of use, so can be deleted and recreated on the
1906fly while the VNC server is active. If missing, it will default
1907to denying access.
1908
1909@item sasl
1910
1911Require that the client use SASL to authenticate with the VNC server.
1912The exact choice of authentication method used is controlled from the
1913system / user's SASL configuration file for the 'qemu' service. This
1914is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1915unprivileged user, an environment variable SASL_CONF_PATH can be used
1916to make it search alternate locations for the service config.
1917While some SASL auth methods can also provide data encryption (eg GSSAPI),
1918it is recommended that SASL always be combined with the 'tls' and
1919'x509' settings to enable use of SSL and server certificates. This
1920ensures a data encryption preventing compromise of authentication
1921credentials. See the @ref{vnc_security} section for details on using
1922SASL authentication.
1923
1924@item sasl-authz=@var{ID}
1925
1926Provides the ID of the QAuthZ authorization object against which
1927the client's SASL username will validated. This object is
1928only resolved at time of use, so can be deleted and recreated on the
1929fly while the VNC server is active. If missing, it will default
1930to denying access.
1931
1932@item acl
1933
1934Legacy method for enabling authorization of clients against the
1935x509 distinguished name and SASL username. It results in the creation
1936of two @code{authz-list} objects with IDs of @code{vnc.username} and
1937@code{vnc.x509dname}. The rules for these objects must be configured
1938with the HMP ACL commands.
1939
1940This option is deprecated and should no longer be used. The new
1941@option{sasl-authz} and @option{tls-authz} options are a
1942replacement.
1943
1944@item lossy
1945
1946Enable lossy compression methods (gradient, JPEG, ...). If this
1947option is set, VNC client may receive lossy framebuffer updates
1948depending on its encoding settings. Enabling this option can save
1949a lot of bandwidth at the expense of quality.
1950
1951@item non-adaptive
1952
1953Disable adaptive encodings. Adaptive encodings are enabled by default.
1954An adaptive encoding will try to detect frequently updated screen regions,
1955and send updates in these regions using a lossy encoding (like JPEG).
1956This can be really helpful to save bandwidth when playing videos. Disabling
1957adaptive encodings restores the original static behavior of encodings
1958like Tight.
1959
1960@item share=[allow-exclusive|force-shared|ignore]
1961
1962Set display sharing policy.  'allow-exclusive' allows clients to ask
1963for exclusive access.  As suggested by the rfb spec this is
1964implemented by dropping other connections.  Connecting multiple
1965clients in parallel requires all clients asking for a shared session
1966(vncviewer: -shared switch).  This is the default.  'force-shared'
1967disables exclusive client access.  Useful for shared desktop sessions,
1968where you don't want someone forgetting specify -shared disconnect
1969everybody else.  'ignore' completely ignores the shared flag and
1970allows everybody connect unconditionally.  Doesn't conform to the rfb
1971spec but is traditional QEMU behavior.
1972
1973@item key-delay-ms
1974
1975Set keyboard delay, for key down and key up events, in milliseconds.
1976Default is 10.  Keyboards are low-bandwidth devices, so this slowdown
1977can help the device and guest to keep up and not lose events in case
1978events are arriving in bulk.  Possible causes for the latter are flaky
1979network connections, or scripts for automated testing.
1980
1981@item audiodev=@var{audiodev}
1982
1983Use the specified @var{audiodev} when the VNC client requests audio
1984transmission. When not using an -audiodev argument, this option must
1985be omitted, otherwise is must be present and specify a valid audiodev.
1986
1987@end table
1988ETEXI
1989
1990STEXI
1991@end table
1992ETEXI
1993ARCHHEADING(, QEMU_ARCH_I386)
1994
1995ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
1996STEXI
1997@table @option
1998ETEXI
1999
2000DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
2001    "-win2k-hack     use it when installing Windows 2000 to avoid a disk full bug\n",
2002    QEMU_ARCH_I386)
2003STEXI
2004@item -win2k-hack
2005@findex -win2k-hack
2006Use it when installing Windows 2000 to avoid a disk full bug. After
2007Windows 2000 is installed, you no longer need this option (this option
2008slows down the IDE transfers).
2009ETEXI
2010
2011DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
2012    "-no-fd-bootchk  disable boot signature checking for floppy disks\n",
2013    QEMU_ARCH_I386)
2014STEXI
2015@item -no-fd-bootchk
2016@findex -no-fd-bootchk
2017Disable boot signature checking for floppy disks in BIOS. May
2018be needed to boot from old floppy disks.
2019ETEXI
2020
2021DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
2022           "-no-acpi        disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2023STEXI
2024@item -no-acpi
2025@findex -no-acpi
2026Disable ACPI (Advanced Configuration and Power Interface) support. Use
2027it if your guest OS complains about ACPI problems (PC target machine
2028only).
2029ETEXI
2030
2031DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
2032    "-no-hpet        disable HPET\n", QEMU_ARCH_I386)
2033STEXI
2034@item -no-hpet
2035@findex -no-hpet
2036Disable HPET support.
2037ETEXI
2038
2039DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
2040    "-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"
2041    "                ACPI table description\n", QEMU_ARCH_I386)
2042STEXI
2043@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}]...]
2044@findex -acpitable
2045Add ACPI table with specified header fields and context from specified files.
2046For file=, take whole ACPI table from the specified files, including all
2047ACPI headers (possible overridden by other options).
2048For data=, only data
2049portion of the table is used, all header information is specified in the
2050command line.
2051If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id
2052fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
2053to ensure the field matches required by the Microsoft SLIC spec and the ACPI
2054spec.
2055ETEXI
2056
2057DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
2058    "-smbios file=binary\n"
2059    "                load SMBIOS entry from binary file\n"
2060    "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
2061    "              [,uefi=on|off]\n"
2062    "                specify SMBIOS type 0 fields\n"
2063    "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2064    "              [,uuid=uuid][,sku=str][,family=str]\n"
2065    "                specify SMBIOS type 1 fields\n"
2066    "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
2067    "              [,asset=str][,location=str]\n"
2068    "                specify SMBIOS type 2 fields\n"
2069    "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
2070    "              [,sku=str]\n"
2071    "                specify SMBIOS type 3 fields\n"
2072    "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
2073    "              [,asset=str][,part=str]\n"
2074    "                specify SMBIOS type 4 fields\n"
2075    "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
2076    "               [,asset=str][,part=str][,speed=%d]\n"
2077    "                specify SMBIOS type 17 fields\n",
2078    QEMU_ARCH_I386 | QEMU_ARCH_ARM)
2079STEXI
2080@item -smbios file=@var{binary}
2081@findex -smbios
2082Load SMBIOS entry from binary file.
2083
2084@item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
2085Specify SMBIOS type 0 fields
2086
2087@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}]
2088Specify SMBIOS type 1 fields
2089
2090@item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}]
2091Specify SMBIOS type 2 fields
2092
2093@item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
2094Specify SMBIOS type 3 fields
2095
2096@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
2097Specify SMBIOS type 4 fields
2098
2099@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}]
2100Specify SMBIOS type 17 fields
2101ETEXI
2102
2103STEXI
2104@end table
2105ETEXI
2106DEFHEADING()
2107
2108DEFHEADING(Network options:)
2109STEXI
2110@table @option
2111ETEXI
2112
2113DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
2114#ifdef CONFIG_SLIRP
2115    "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n"
2116    "         [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
2117    "         [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
2118    "         [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
2119    "         [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
2120#ifndef _WIN32
2121                                             "[,smb=dir[,smbserver=addr]]\n"
2122#endif
2123    "                configure a user mode network backend with ID 'str',\n"
2124    "                its DHCP server and optional services\n"
2125#endif
2126#ifdef _WIN32
2127    "-netdev tap,id=str,ifname=name\n"
2128    "                configure a host TAP network backend with ID 'str'\n"
2129#else
2130    "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
2131    "         [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
2132    "         [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
2133    "         [,poll-us=n]\n"
2134    "                configure a host TAP network backend with ID 'str'\n"
2135    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2136    "                use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
2137    "                to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
2138    "                to deconfigure it\n"
2139    "                use '[down]script=no' to disable script execution\n"
2140    "                use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
2141    "                configure it\n"
2142    "                use 'fd=h' to connect to an already opened TAP interface\n"
2143    "                use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
2144    "                use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
2145    "                default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
2146    "                use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
2147    "                use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
2148    "                use vhost=on to enable experimental in kernel accelerator\n"
2149    "                    (only has effect for virtio guests which use MSIX)\n"
2150    "                use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
2151    "                use 'vhostfd=h' to connect to an already opened vhost net device\n"
2152    "                use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
2153    "                use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
2154    "                use 'poll-us=n' to speciy the maximum number of microseconds that could be\n"
2155    "                spent on busy polling for vhost net\n"
2156    "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
2157    "                configure a host TAP network backend with ID 'str' that is\n"
2158    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
2159    "                using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
2160#endif
2161#ifdef __linux__
2162    "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
2163    "         [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n"
2164    "         [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n"
2165    "         [,rxcookie=rxcookie][,offset=offset]\n"
2166    "                configure a network backend with ID 'str' connected to\n"
2167    "                an Ethernet over L2TPv3 pseudowire.\n"
2168    "                Linux kernel 3.3+ as well as most routers can talk\n"
2169    "                L2TPv3. This transport allows connecting a VM to a VM,\n"
2170    "                VM to a router and even VM to Host. It is a nearly-universal\n"
2171    "                standard (RFC3391). Note - this implementation uses static\n"
2172    "                pre-configured tunnels (same as the Linux kernel).\n"
2173    "                use 'src=' to specify source address\n"
2174    "                use 'dst=' to specify destination address\n"
2175    "                use 'udp=on' to specify udp encapsulation\n"
2176    "                use 'srcport=' to specify source udp port\n"
2177    "                use 'dstport=' to specify destination udp port\n"
2178    "                use 'ipv6=on' to force v6\n"
2179    "                L2TPv3 uses cookies to prevent misconfiguration as\n"
2180    "                well as a weak security measure\n"
2181    "                use 'rxcookie=0x012345678' to specify a rxcookie\n"
2182    "                use 'txcookie=0x012345678' to specify a txcookie\n"
2183    "                use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
2184    "                use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
2185    "                use 'pincounter=on' to work around broken counter handling in peer\n"
2186    "                use 'offset=X' to add an extra offset between header and data\n"
2187#endif
2188    "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
2189    "                configure a network backend to connect to another network\n"
2190    "                using a socket connection\n"
2191    "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
2192    "                configure a network backend to connect to a multicast maddr and port\n"
2193    "                use 'localaddr=addr' to specify the host address to send packets from\n"
2194    "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
2195    "                configure a network backend to connect to another network\n"
2196    "                using an UDP tunnel\n"
2197#ifdef CONFIG_VDE
2198    "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
2199    "                configure a network backend to connect to port 'n' of a vde switch\n"
2200    "                running on host and listening for incoming connections on 'socketpath'.\n"
2201    "                Use group 'groupname' and mode 'octalmode' to change default\n"
2202    "                ownership and permissions for communication port.\n"
2203#endif
2204#ifdef CONFIG_NETMAP
2205    "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
2206    "                attach to the existing netmap-enabled network interface 'name', or to a\n"
2207    "                VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
2208    "                netmap device, defaults to '/dev/netmap')\n"
2209#endif
2210#ifdef CONFIG_POSIX
2211    "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
2212    "                configure a vhost-user network, backed by a chardev 'dev'\n"
2213#endif
2214    "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
2215    "                configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
2216DEF("nic", HAS_ARG, QEMU_OPTION_nic,
2217    "-nic [tap|bridge|"
2218#ifdef CONFIG_SLIRP
2219    "user|"
2220#endif
2221#ifdef __linux__
2222    "l2tpv3|"
2223#endif
2224#ifdef CONFIG_VDE
2225    "vde|"
2226#endif
2227#ifdef CONFIG_NETMAP
2228    "netmap|"
2229#endif
2230#ifdef CONFIG_POSIX
2231    "vhost-user|"
2232#endif
2233    "socket][,option][,...][mac=macaddr]\n"
2234    "                initialize an on-board / default host NIC (using MAC address\n"
2235    "                macaddr) and connect it to the given host network backend\n"
2236    "-nic none       use it alone to have zero network devices (the default is to\n"
2237    "                provided a 'user' network connection)\n",
2238    QEMU_ARCH_ALL)
2239DEF("net", HAS_ARG, QEMU_OPTION_net,
2240    "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
2241    "                configure or create an on-board (or machine default) NIC and\n"
2242    "                connect it to hub 0 (please use -nic unless you need a hub)\n"
2243    "-net ["
2244#ifdef CONFIG_SLIRP
2245    "user|"
2246#endif
2247    "tap|"
2248    "bridge|"
2249#ifdef CONFIG_VDE
2250    "vde|"
2251#endif
2252#ifdef CONFIG_NETMAP
2253    "netmap|"
2254#endif
2255    "socket][,option][,option][,...]\n"
2256    "                old way to initialize a host network interface\n"
2257    "                (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
2258STEXI
2259@item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
2260@findex -nic
2261This option is a shortcut for configuring both the on-board (default) guest
2262NIC hardware and the host network backend in one go. The host backend options
2263are the same as with the corresponding @option{-netdev} options below.
2264The guest NIC model can be set with @option{model=@var{modelname}}.
2265Use @option{model=help} to list the available device types.
2266The hardware MAC address can be set with @option{mac=@var{macaddr}}.
2267
2268The following two example do exactly the same, to show how @option{-nic} can
2269be used to shorten the command line length (note that the e1000 is the default
2270on i386, so the @option{model=e1000} parameter could even be omitted here, too):
2271@example
2272qemu-system-i386 -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
2273qemu-system-i386 -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
2274@end example
2275
2276@item -nic none
2277Indicate that no network devices should be configured. It is used to override
2278the default configuration (default NIC with ``user'' host network backend)
2279which is activated if no other networking options are provided.
2280
2281@item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
2282@findex -netdev
2283Configure user mode host network backend which requires no administrator
2284privilege to run. Valid options are:
2285
2286@table @option
2287@item id=@var{id}
2288Assign symbolic name for use in monitor commands.
2289
2290@item ipv4=on|off and ipv6=on|off
2291Specify that either IPv4 or IPv6 must be enabled. If neither is specified
2292both protocols are enabled.
2293
2294@item net=@var{addr}[/@var{mask}]
2295Set IP network address the guest will see. Optionally specify the netmask,
2296either in the form a.b.c.d or as number of valid top-most bits. Default is
229710.0.2.0/24.
2298
2299@item host=@var{addr}
2300Specify the guest-visible address of the host. Default is the 2nd IP in the
2301guest network, i.e. x.x.x.2.
2302
2303@item ipv6-net=@var{addr}[/@var{int}]
2304Set IPv6 network address the guest will see (default is fec0::/64). The
2305network prefix is given in the usual hexadecimal IPv6 address
2306notation. The prefix size is optional, and is given as the number of
2307valid top-most bits (default is 64).
2308
2309@item ipv6-host=@var{addr}
2310Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2311the guest network, i.e. xxxx::2.
2312
2313@item restrict=on|off
2314If this option is enabled, the guest will be isolated, i.e. it will not be
2315able to contact the host and no guest IP packets will be routed over the host
2316to the outside. This option does not affect any explicitly set forwarding rules.
2317
2318@item hostname=@var{name}
2319Specifies the client hostname reported by the built-in DHCP server.
2320
2321@item dhcpstart=@var{addr}
2322Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2323is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2324
2325@item dns=@var{addr}
2326Specify the guest-visible address of the virtual nameserver. The address must
2327be different from the host address. Default is the 3rd IP in the guest network,
2328i.e. x.x.x.3.
2329
2330@item ipv6-dns=@var{addr}
2331Specify the guest-visible address of the IPv6 virtual nameserver. The address
2332must be different from the host address. Default is the 3rd IP in the guest
2333network, i.e. xxxx::3.
2334
2335@item dnssearch=@var{domain}
2336Provides an entry for the domain-search list sent by the built-in
2337DHCP server. More than one domain suffix can be transmitted by specifying
2338this option multiple times. If supported, this will cause the guest to
2339automatically try to append the given domain suffix(es) in case a domain name
2340can not be resolved.
2341
2342Example:
2343@example
2344qemu-system-i386 -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2345@end example
2346
2347@item domainname=@var{domain}
2348Specifies the client domain name reported by the built-in DHCP server.
2349
2350@item tftp=@var{dir}
2351When using the user mode network stack, activate a built-in TFTP
2352server. The files in @var{dir} will be exposed as the root of a TFTP server.
2353The TFTP client on the guest must be configured in binary mode (use the command
2354@code{bin} of the Unix TFTP client).
2355
2356@item tftp-server-name=@var{name}
2357In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
235866). This can be used to advise the guest to load boot files or configurations
2359from a different server than the host address.
2360
2361@item bootfile=@var{file}
2362When using the user mode network stack, broadcast @var{file} as the BOOTP
2363filename. In conjunction with @option{tftp}, this can be used to network boot
2364a guest from a local directory.
2365
2366Example (using pxelinux):
2367@example
2368qemu-system-i386 -hda linux.img -boot n -device e1000,netdev=n1 \
2369    -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2370@end example
2371
2372@item smb=@var{dir}[,smbserver=@var{addr}]
2373When using the user mode network stack, activate a built-in SMB
2374server so that Windows OSes can access to the host files in @file{@var{dir}}
2375transparently. The IP address of the SMB server can be set to @var{addr}. By
2376default the 4th IP in the guest network is used, i.e. x.x.x.4.
2377
2378In the guest Windows OS, the line:
2379@example
238010.0.2.4 smbserver
2381@end example
2382must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2383or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2384
2385Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2386
2387Note that a SAMBA server must be installed on the host OS.
2388
2389@item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2390Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2391the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2392@var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2393given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2394be bound to a specific host interface. If no connection type is set, TCP is
2395used. This option can be given multiple times.
2396
2397For example, to redirect host X11 connection from screen 1 to guest
2398screen 0, use the following:
2399
2400@example
2401# on the host
2402qemu-system-i386 -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2403# this host xterm should open in the guest X11 server
2404xterm -display :1
2405@end example
2406
2407To redirect telnet connections from host port 5555 to telnet port on
2408the guest, use the following:
2409
2410@example
2411# on the host
2412qemu-system-i386 -nic user,hostfwd=tcp::5555-:23
2413telnet localhost 5555
2414@end example
2415
2416Then when you use on the host @code{telnet localhost 5555}, you
2417connect to the guest telnet server.
2418
2419@item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2420@itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2421Forward guest TCP connections to the IP address @var{server} on port @var{port}
2422to the character device @var{dev} or to a program executed by @var{cmd:command}
2423which gets spawned for each connection. This option can be given multiple times.
2424
2425You can either use a chardev directly and have that one used throughout QEMU's
2426lifetime, like in the following example:
2427
2428@example
2429# open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2430# the guest accesses it
2431qemu-system-i386 -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2432@end example
2433
2434Or you can execute a command on every TCP connection established by the guest,
2435so that QEMU behaves similar to an inetd process for that virtual server:
2436
2437@example
2438# call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2439# and connect the TCP stream to its stdin/stdout
2440qemu-system-i386 -nic  'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2441@end example
2442
2443@end table
2444
2445@item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
2446Configure a host TAP network backend with ID @var{id}.
2447
2448Use the network script @var{file} to configure it and the network script
2449@var{dfile} to deconfigure it. If @var{name} is not provided, the OS
2450automatically provides one. The default network configure script is
2451@file{/etc/qemu-ifup} and the default network deconfigure script is
2452@file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no}
2453to disable script execution.
2454
2455If running QEMU as an unprivileged user, use the network helper
2456@var{helper} to configure the TAP interface and attach it to the bridge.
2457The default network helper executable is @file{/path/to/qemu-bridge-helper}
2458and the default bridge device is @file{br0}.
2459
2460@option{fd}=@var{h} can be used to specify the handle of an already
2461opened host TAP interface.
2462
2463Examples:
2464
2465@example
2466#launch a QEMU instance with the default network script
2467qemu-system-i386 linux.img -nic tap
2468@end example
2469
2470@example
2471#launch a QEMU instance with two NICs, each one connected
2472#to a TAP device
2473qemu-system-i386 linux.img \
2474        -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \
2475        -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2476@end example
2477
2478@example
2479#launch a QEMU instance with the default network helper to
2480#connect a TAP device to bridge br0
2481qemu-system-i386 linux.img -device virtio-net-pci,netdev=n1 \
2482        -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2483@end example
2484
2485@item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}]
2486Connect a host TAP network interface to a host bridge device.
2487
2488Use the network helper @var{helper} to configure the TAP interface and
2489attach it to the bridge. The default network helper executable is
2490@file{/path/to/qemu-bridge-helper} and the default bridge
2491device is @file{br0}.
2492
2493Examples:
2494
2495@example
2496#launch a QEMU instance with the default network helper to
2497#connect a TAP device to bridge br0
2498qemu-system-i386 linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2499@end example
2500
2501@example
2502#launch a QEMU instance with the default network helper to
2503#connect a TAP device to bridge qemubr0
2504qemu-system-i386 linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2505@end example
2506
2507@item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2508
2509This host network backend can be used to connect the guest's network to
2510another QEMU virtual machine using a TCP socket connection. If @option{listen}
2511is specified, QEMU waits for incoming connections on @var{port}
2512(@var{host} is optional). @option{connect} is used to connect to
2513another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2514specifies an already opened TCP socket.
2515
2516Example:
2517@example
2518# launch a first QEMU instance
2519qemu-system-i386 linux.img \
2520                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2521                 -netdev socket,id=n1,listen=:1234
2522# connect the network of this instance to the network of the first instance
2523qemu-system-i386 linux.img \
2524                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2525                 -netdev socket,id=n2,connect=127.0.0.1:1234
2526@end example
2527
2528@item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2529
2530Configure a socket host network backend to share the guest's network traffic
2531with another QEMU virtual machines using a UDP multicast socket, effectively
2532making a bus for every QEMU with same multicast address @var{maddr} and @var{port}.
2533NOTES:
2534@enumerate
2535@item
2536Several QEMU can be running on different hosts and share same bus (assuming
2537correct multicast setup for these hosts).
2538@item
2539mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
2540@url{http://user-mode-linux.sf.net}.
2541@item
2542Use @option{fd=h} to specify an already opened UDP multicast socket.
2543@end enumerate
2544
2545Example:
2546@example
2547# launch one QEMU instance
2548qemu-system-i386 linux.img \
2549                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2550                 -netdev socket,id=n1,mcast=230.0.0.1:1234
2551# launch another QEMU instance on same "bus"
2552qemu-system-i386 linux.img \
2553                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2554                 -netdev socket,id=n2,mcast=230.0.0.1:1234
2555# launch yet another QEMU instance on same "bus"
2556qemu-system-i386 linux.img \
2557                 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \
2558                 -netdev socket,id=n3,mcast=230.0.0.1:1234
2559@end example
2560
2561Example (User Mode Linux compat.):
2562@example
2563# launch QEMU instance (note mcast address selected is UML's default)
2564qemu-system-i386 linux.img \
2565                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2566                 -netdev socket,id=n1,mcast=239.192.168.1:1102
2567# launch UML
2568/path/to/linux ubd0=/path/to/root_fs eth0=mcast
2569@end example
2570
2571Example (send packets from host's 1.2.3.4):
2572@example
2573qemu-system-i386 linux.img \
2574                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2575                 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2576@end example
2577
2578@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}]
2579Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3391) is a
2580popular protocol to transport Ethernet (and other Layer 2) data frames between
2581two systems. It is present in routers, firewalls and the Linux kernel
2582(from version 3.3 onwards).
2583
2584This transport allows a VM to communicate to another VM, router or firewall directly.
2585
2586@table @option
2587@item src=@var{srcaddr}
2588    source address (mandatory)
2589@item dst=@var{dstaddr}
2590    destination address (mandatory)
2591@item udp
2592    select udp encapsulation (default is ip).
2593@item srcport=@var{srcport}
2594    source udp port.
2595@item dstport=@var{dstport}
2596    destination udp port.
2597@item ipv6
2598    force v6, otherwise defaults to v4.
2599@item rxcookie=@var{rxcookie}
2600@itemx txcookie=@var{txcookie}
2601    Cookies are a weak form of security in the l2tpv3 specification.
2602Their function is mostly to prevent misconfiguration. By default they are 32
2603bit.
2604@item cookie64
2605    Set cookie size to 64 bit instead of the default 32
2606@item counter=off
2607    Force a 'cut-down' L2TPv3 with no counter as in
2608draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2609@item pincounter=on
2610    Work around broken counter handling in peer. This may also help on
2611networks which have packet reorder.
2612@item offset=@var{offset}
2613    Add an extra offset between header and data
2614@end table
2615
2616For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan
2617on the remote Linux host 1.2.3.4:
2618@example
2619# Setup tunnel on linux host using raw ip as encapsulation
2620# on 1.2.3.4
2621ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \
2622    encap udp udp_sport 16384 udp_dport 16384
2623ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \
2624    0xFFFFFFFF peer_session_id 0xFFFFFFFF
2625ifconfig vmtunnel0 mtu 1500
2626ifconfig vmtunnel0 up
2627brctl addif br-lan vmtunnel0
2628
2629
2630# on 4.3.2.1
2631# launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2632
2633qemu-system-i386 linux.img -device e1000,netdev=n1 \
2634    -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2635
2636@end example
2637
2638@item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2639Configure VDE backend to connect to PORT @var{n} of a vde switch running on host and
2640listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}
2641and MODE @var{octalmode} to change default ownership and permissions for
2642communication port. This option is only available if QEMU has been compiled
2643with vde support enabled.
2644
2645Example:
2646@example
2647# launch vde switch
2648vde_switch -F -sock /tmp/myswitch
2649# launch QEMU instance
2650qemu-system-i386 linux.img -nic vde,sock=/tmp/myswitch
2651@end example
2652
2653@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
2654
2655Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
2656be a unix domain socket backed one. The vhost-user uses a specifically defined
2657protocol to pass vhost ioctl replacement messages to an application on the other
2658end of the socket. On non-MSIX guests, the feature can be forced with
2659@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
2660be created for multiqueue vhost-user.
2661
2662Example:
2663@example
2664qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
2665     -numa node,memdev=mem \
2666     -chardev socket,id=chr0,path=/path/to/socket \
2667     -netdev type=vhost-user,id=net0,chardev=chr0 \
2668     -device virtio-net-pci,netdev=net0
2669@end example
2670
2671@item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}]
2672
2673Create a hub port on the emulated hub with ID @var{hubid}.
2674
2675The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2676single netdev. Alternatively, you can also connect the hubport to another
2677netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option.
2678
2679@item -net nic[,netdev=@var{nd}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}]
2680@findex -net
2681Legacy option to configure or create an on-board (or machine default) Network
2682Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e.
2683the default hub), or to the netdev @var{nd}.
2684The NIC is an e1000 by default on the PC target. Optionally, the MAC address
2685can be changed to @var{mac}, the device address set to @var{addr} (PCI cards
2686only), and a @var{name} can be assigned for use in monitor commands.
2687Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
2688that the card should have; this option currently only affects virtio cards; set
2689@var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
2690NIC is created.  QEMU can emulate several different models of network card.
2691Use @code{-net nic,model=help} for a list of available devices for your target.
2692
2693@item -net user|tap|bridge|socket|l2tpv3|vde[,...][,name=@var{name}]
2694Configure a host network backend (with the options corresponding to the same
2695@option{-netdev} option) and connect it to the emulated hub 0 (the default
2696hub). Use @var{name} to specify the name of the hub port.
2697ETEXI
2698
2699STEXI
2700@end table
2701ETEXI
2702DEFHEADING()
2703
2704DEFHEADING(Character device options:)
2705
2706DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
2707    "-chardev help\n"
2708    "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2709    "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2710    "         [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2711    "         [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n"
2712    "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2713    "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2714    "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2715    "         [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2716    "         [,logfile=PATH][,logappend=on|off]\n"
2717    "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2718    "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2719    "         [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2720    "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2721    "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2722    "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2723#ifdef _WIN32
2724    "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2725    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2726#else
2727    "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2728    "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2729#endif
2730#ifdef CONFIG_BRLAPI
2731    "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2732#endif
2733#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
2734        || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
2735    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2736    "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2737#endif
2738#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
2739    "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2740    "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2741#endif
2742#if defined(CONFIG_SPICE)
2743    "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2744    "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2745#endif
2746    , QEMU_ARCH_ALL
2747)
2748
2749STEXI
2750
2751The general form of a character device option is:
2752@table @option
2753@item -chardev @var{backend},id=@var{id}[,mux=on|off][,@var{options}]
2754@findex -chardev
2755Backend is one of:
2756@option{null},
2757@option{socket},
2758@option{udp},
2759@option{msmouse},
2760@option{vc},
2761@option{ringbuf},
2762@option{file},
2763@option{pipe},
2764@option{console},
2765@option{serial},
2766@option{pty},
2767@option{stdio},
2768@option{braille},
2769@option{tty},
2770@option{parallel},
2771@option{parport},
2772@option{spicevmc},
2773@option{spiceport}.
2774The specific backend will determine the applicable options.
2775
2776Use @code{-chardev help} to print all available chardev backend types.
2777
2778All devices must have an id, which can be any string up to 127 characters long.
2779It is used to uniquely identify this device in other command line directives.
2780
2781A character device may be used in multiplexing mode by multiple front-ends.
2782Specify @option{mux=on} to enable this mode.
2783A multiplexer is a "1:N" device, and here the "1" end is your specified chardev
2784backend, and the "N" end is the various parts of QEMU that can talk to a chardev.
2785If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will
2786create a multiplexer with your specified ID, and you can then configure multiple
2787front ends to use that chardev ID for their input/output. Up to four different
2788front ends can be connected to a single multiplexed chardev. (Without
2789multiplexing enabled, a chardev can only be used by a single front end.)
2790For instance you could use this to allow a single stdio chardev to be used by
2791two serial ports and the QEMU monitor:
2792
2793@example
2794-chardev stdio,mux=on,id=char0 \
2795-mon chardev=char0,mode=readline \
2796-serial chardev:char0 \
2797-serial chardev:char0
2798@end example
2799
2800You can have more than one multiplexer in a system configuration; for instance
2801you could have a TCP port multiplexed between UART 0 and UART 1, and stdio
2802multiplexed between the QEMU monitor and a parallel port:
2803
2804@example
2805-chardev stdio,mux=on,id=char0 \
2806-mon chardev=char0,mode=readline \
2807-parallel chardev:char0 \
2808-chardev tcp,...,mux=on,id=char1 \
2809-serial chardev:char1 \
2810-serial chardev:char1
2811@end example
2812
2813When you're using a multiplexed character device, some escape sequences are
2814interpreted in the input. @xref{mux_keys, Keys in the character backend
2815multiplexer}.
2816
2817Note that some other command line options may implicitly create multiplexed
2818character backends; for instance @option{-serial mon:stdio} creates a
2819multiplexed stdio backend connected to the serial port and the QEMU monitor,
2820and @option{-nographic} also multiplexes the console and the monitor to
2821stdio.
2822
2823There is currently no support for multiplexing in the other direction
2824(where a single QEMU front end takes input and output from multiple chardevs).
2825
2826Every backend supports the @option{logfile} option, which supplies the path
2827to a file to record all data transmitted via the backend. The @option{logappend}
2828option controls whether the log file will be truncated or appended to when
2829opened.
2830
2831@end table
2832
2833The available backends are:
2834
2835@table @option
2836@item -chardev null,id=@var{id}
2837A void device. This device will not emit any data, and will drop any data it
2838receives. The null backend does not take any options.
2839
2840@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}][,tls-authz=@var{id}]
2841
2842Create a two-way stream socket, which can be either a TCP or a unix socket. A
2843unix socket will be created if @option{path} is specified. Behaviour is
2844undefined if TCP options are specified for a unix socket.
2845
2846@option{server} specifies that the socket shall be a listening socket.
2847
2848@option{nowait} specifies that QEMU should not block waiting for a client to
2849connect to a listening socket.
2850
2851@option{telnet} specifies that traffic on the socket should interpret telnet
2852escape sequences.
2853
2854@option{websocket} specifies that the socket uses WebSocket protocol for
2855communication.
2856
2857@option{reconnect} sets the timeout for reconnecting on non-server sockets when
2858the remote end goes away.  qemu will delay this many seconds and then attempt
2859to reconnect.  Zero disables reconnecting, and is the default.
2860
2861@option{tls-creds} requests enablement of the TLS protocol for encryption,
2862and specifies the id of the TLS credentials to use for the handshake. The
2863credentials must be previously created with the @option{-object tls-creds}
2864argument.
2865
2866@option{tls-auth} provides the ID of the QAuthZ authorization object against
2867which the client's x509 distinguished name will be validated. This object is
2868only resolved at time of use, so can be deleted and recreated on the fly
2869while the chardev server is active. If missing, it will default to denying
2870access.
2871
2872TCP and unix socket options are given below:
2873
2874@table @option
2875
2876@item TCP options: port=@var{port}[,host=@var{host}][,to=@var{to}][,ipv4][,ipv6][,nodelay]
2877
2878@option{host} for a listening socket specifies the local address to be bound.
2879For a connecting socket species the remote host to connect to. @option{host} is
2880optional for listening sockets. If not specified it defaults to @code{0.0.0.0}.
2881
2882@option{port} for a listening socket specifies the local port to be bound. For a
2883connecting socket specifies the port on the remote host to connect to.
2884@option{port} can be given as either a port number or a service name.
2885@option{port} is required.
2886
2887@option{to} is only relevant to listening sockets. If it is specified, and
2888@option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up
2889to and including @option{to} until it succeeds. @option{to} must be specified
2890as a port number.
2891
2892@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2893If neither is specified the socket may use either protocol.
2894
2895@option{nodelay} disables the Nagle algorithm.
2896
2897@item unix options: path=@var{path}
2898
2899@option{path} specifies the local path of the unix socket. @option{path} is
2900required.
2901
2902@end table
2903
2904@item -chardev udp,id=@var{id}[,host=@var{host}],port=@var{port}[,localaddr=@var{localaddr}][,localport=@var{localport}][,ipv4][,ipv6]
2905
2906Sends all traffic from the guest to a remote host over UDP.
2907
2908@option{host} specifies the remote host to connect to. If not specified it
2909defaults to @code{localhost}.
2910
2911@option{port} specifies the port on the remote host to connect to. @option{port}
2912is required.
2913
2914@option{localaddr} specifies the local address to bind to. If not specified it
2915defaults to @code{0.0.0.0}.
2916
2917@option{localport} specifies the local port to bind to. If not specified any
2918available local port will be used.
2919
2920@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2921If neither is specified the device may use either protocol.
2922
2923@item -chardev msmouse,id=@var{id}
2924
2925Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not
2926take any options.
2927
2928@item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
2929
2930Connect to a QEMU text console. @option{vc} may optionally be given a specific
2931size.
2932
2933@option{width} and @option{height} specify the width and height respectively of
2934the console, in pixels.
2935
2936@option{cols} and @option{rows} specify that the console be sized to fit a text
2937console with the given dimensions.
2938
2939@item -chardev ringbuf,id=@var{id}[,size=@var{size}]
2940
2941Create a ring buffer with fixed size @option{size}.
2942@var{size} must be a power of two and defaults to @code{64K}.
2943
2944@item -chardev file,id=@var{id},path=@var{path}
2945
2946Log all traffic received from the guest to a file.
2947
2948@option{path} specifies the path of the file to be opened. This file will be
2949created if it does not already exist, and overwritten if it does. @option{path}
2950is required.
2951
2952@item -chardev pipe,id=@var{id},path=@var{path}
2953
2954Create a two-way connection to the guest. The behaviour differs slightly between
2955Windows hosts and other hosts:
2956
2957On Windows, a single duplex pipe will be created at
2958@file{\\.pipe\@option{path}}.
2959
2960On other hosts, 2 pipes will be created called @file{@option{path}.in} and
2961@file{@option{path}.out}. Data written to @file{@option{path}.in} will be
2962received by the guest. Data written by the guest can be read from
2963@file{@option{path}.out}. QEMU will not create these fifos, and requires them to
2964be present.
2965
2966@option{path} forms part of the pipe path as described above. @option{path} is
2967required.
2968
2969@item -chardev console,id=@var{id}
2970
2971Send traffic from the guest to QEMU's standard output. @option{console} does not
2972take any options.
2973
2974@option{console} is only available on Windows hosts.
2975
2976@item -chardev serial,id=@var{id},path=@option{path}
2977
2978Send traffic from the guest to a serial device on the host.
2979
2980On Unix hosts serial will actually accept any tty device,
2981not only serial lines.
2982
2983@option{path} specifies the name of the serial device to open.
2984
2985@item -chardev pty,id=@var{id}
2986
2987Create a new pseudo-terminal on the host and connect to it. @option{pty} does
2988not take any options.
2989
2990@option{pty} is not available on Windows hosts.
2991
2992@item -chardev stdio,id=@var{id}[,signal=on|off]
2993Connect to standard input and standard output of the QEMU process.
2994
2995@option{signal} controls if signals are enabled on the terminal, that includes
2996exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
2997default, use @option{signal=off} to disable it.
2998
2999@item -chardev braille,id=@var{id}
3000
3001Connect to a local BrlAPI server. @option{braille} does not take any options.
3002
3003@item -chardev tty,id=@var{id},path=@var{path}
3004
3005@option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
3006DragonFlyBSD hosts.  It is an alias for @option{serial}.
3007
3008@option{path} specifies the path to the tty. @option{path} is required.
3009
3010@item -chardev parallel,id=@var{id},path=@var{path}
3011@itemx -chardev parport,id=@var{id},path=@var{path}
3012
3013@option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
3014
3015Connect to a local parallel port.
3016
3017@option{path} specifies the path to the parallel port device. @option{path} is
3018required.
3019
3020@item -chardev spicevmc,id=@var{id},debug=@var{debug},name=@var{name}
3021
3022@option{spicevmc} is only available when spice support is built in.
3023
3024@option{debug} debug level for spicevmc
3025
3026@option{name} name of spice channel to connect to
3027
3028Connect to a spice virtual machine channel, such as vdiport.
3029
3030@item -chardev spiceport,id=@var{id},debug=@var{debug},name=@var{name}
3031
3032@option{spiceport} is only available when spice support is built in.
3033
3034@option{debug} debug level for spicevmc
3035
3036@option{name} name of spice port to connect to
3037
3038Connect to a spice port, allowing a Spice client to handle the traffic
3039identified by a name (preferably a fqdn).
3040ETEXI
3041
3042STEXI
3043@end table
3044ETEXI
3045DEFHEADING()
3046
3047DEFHEADING(Bluetooth(R) options:)
3048STEXI
3049@table @option
3050ETEXI
3051
3052DEF("bt", HAS_ARG, QEMU_OPTION_bt, \
3053    "-bt hci,null    dumb bluetooth HCI - doesn't respond to commands\n" \
3054    "-bt hci,host[:id]\n" \
3055    "                use host's HCI with the given name\n" \
3056    "-bt hci[,vlan=n]\n" \
3057    "                emulate a standard HCI in virtual scatternet 'n'\n" \
3058    "-bt vhci[,vlan=n]\n" \
3059    "                add host computer to virtual scatternet 'n' using VHCI\n" \
3060    "-bt device:dev[,vlan=n]\n" \
3061    "                emulate a bluetooth device 'dev' in scatternet 'n'\n",
3062    QEMU_ARCH_ALL)
3063STEXI
3064@item -bt hci[...]
3065@findex -bt
3066Defines the function of the corresponding Bluetooth HCI.  -bt options
3067are matched with the HCIs present in the chosen machine type.  For
3068example when emulating a machine with only one HCI built into it, only
3069the first @code{-bt hci[...]} option is valid and defines the HCI's
3070logic.  The Transport Layer is decided by the machine type.  Currently
3071the machines @code{n800} and @code{n810} have one HCI and all other
3072machines have none.
3073
3074Note: This option and the whole bluetooth subsystem is considered as deprecated.
3075If you still use it, please send a mail to @email{qemu-devel@@nongnu.org} where
3076you describe your usecase.
3077
3078@anchor{bt-hcis}
3079The following three types are recognized:
3080
3081@table @option
3082@item -bt hci,null
3083(default) The corresponding Bluetooth HCI assumes no internal logic
3084and will not respond to any HCI commands or emit events.
3085
3086@item -bt hci,host[:@var{id}]
3087(@code{bluez} only) The corresponding HCI passes commands / events
3088to / from the physical HCI identified by the name @var{id} (default:
3089@code{hci0}) on the computer running QEMU.  Only available on @code{bluez}
3090capable systems like Linux.
3091
3092@item -bt hci[,vlan=@var{n}]
3093Add a virtual, standard HCI that will participate in the Bluetooth
3094scatternet @var{n} (default @code{0}).  Similarly to @option{-net}
3095VLANs, devices inside a bluetooth network @var{n} can only communicate
3096with other devices in the same network (scatternet).
3097@end table
3098
3099@item -bt vhci[,vlan=@var{n}]
3100(Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached
3101to the host bluetooth stack instead of to the emulated target.  This
3102allows the host and target machines to participate in a common scatternet
3103and communicate.  Requires the Linux @code{vhci} driver installed.  Can
3104be used as following:
3105
3106@example
3107qemu-system-i386 [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5
3108@end example
3109
3110@item -bt device:@var{dev}[,vlan=@var{n}]
3111Emulate a bluetooth device @var{dev} and place it in network @var{n}
3112(default @code{0}).  QEMU can only emulate one type of bluetooth devices
3113currently:
3114
3115@table @option
3116@item keyboard
3117Virtual wireless keyboard implementing the HIDP bluetooth profile.
3118@end table
3119ETEXI
3120
3121STEXI
3122@end table
3123ETEXI
3124DEFHEADING()
3125
3126#ifdef CONFIG_TPM
3127DEFHEADING(TPM device options:)
3128
3129DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
3130    "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
3131    "                use path to provide path to a character device; default is /dev/tpm0\n"
3132    "                use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
3133    "                not provided it will be searched for in /sys/class/misc/tpm?/device\n"
3134    "-tpmdev emulator,id=id,chardev=dev\n"
3135    "                configure the TPM device using chardev backend\n",
3136    QEMU_ARCH_ALL)
3137STEXI
3138
3139The general form of a TPM device option is:
3140@table @option
3141
3142@item -tpmdev @var{backend},id=@var{id}[,@var{options}]
3143@findex -tpmdev
3144
3145The specific backend type will determine the applicable options.
3146The @code{-tpmdev} option creates the TPM backend and requires a
3147@code{-device} option that specifies the TPM frontend interface model.
3148
3149Use @code{-tpmdev help} to print all available TPM backend types.
3150
3151@end table
3152
3153The available backends are:
3154
3155@table @option
3156
3157@item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path}
3158
3159(Linux-host only) Enable access to the host's TPM using the passthrough
3160driver.
3161
3162@option{path} specifies the path to the host's TPM device, i.e., on
3163a Linux host this would be @code{/dev/tpm0}.
3164@option{path} is optional and by default @code{/dev/tpm0} is used.
3165
3166@option{cancel-path} specifies the path to the host TPM device's sysfs
3167entry allowing for cancellation of an ongoing TPM command.
3168@option{cancel-path} is optional and by default QEMU will search for the
3169sysfs entry to use.
3170
3171Some notes about using the host's TPM with the passthrough driver:
3172
3173The TPM device accessed by the passthrough driver must not be
3174used by any other application on the host.
3175
3176Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
3177the VM's firmware (BIOS/UEFI) will not be able to initialize the
3178TPM again and may therefore not show a TPM-specific menu that would
3179otherwise allow the user to configure the TPM, e.g., allow the user to
3180enable/disable or activate/deactivate the TPM.
3181Further, if TPM ownership is released from within a VM then the host's TPM
3182will get disabled and deactivated. To enable and activate the
3183TPM again afterwards, the host has to be rebooted and the user is
3184required to enter the firmware's menu to enable and activate the TPM.
3185If the TPM is left disabled and/or deactivated most TPM commands will fail.
3186
3187To create a passthrough TPM use the following two options:
3188@example
3189-tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
3190@end example
3191Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
3192@code{tpmdev=tpm0} in the device option.
3193
3194@item -tpmdev emulator,id=@var{id},chardev=@var{dev}
3195
3196(Linux-host only) Enable access to a TPM emulator using Unix domain socket based
3197chardev backend.
3198
3199@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
3200
3201To create a TPM emulator backend device with chardev socket backend:
3202@example
3203
3204-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
3205
3206@end example
3207
3208ETEXI
3209
3210STEXI
3211@end table
3212ETEXI
3213DEFHEADING()
3214
3215#endif
3216
3217DEFHEADING(Linux/Multiboot boot specific:)
3218STEXI
3219
3220When using these options, you can use a given Linux or Multiboot
3221kernel without installing it in the disk image. It can be useful
3222for easier testing of various kernels.
3223
3224@table @option
3225ETEXI
3226
3227DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
3228    "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
3229STEXI
3230@item -kernel @var{bzImage}
3231@findex -kernel
3232Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
3233or in multiboot format.
3234ETEXI
3235
3236DEF("append", HAS_ARG, QEMU_OPTION_append, \
3237    "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
3238STEXI
3239@item -append @var{cmdline}
3240@findex -append
3241Use @var{cmdline} as kernel command line
3242ETEXI
3243
3244DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
3245           "-initrd file    use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
3246STEXI
3247@item -initrd @var{file}
3248@findex -initrd
3249Use @var{file} as initial ram disk.
3250
3251@item -initrd "@var{file1} arg=foo,@var{file2}"
3252
3253This syntax is only available with multiboot.
3254
3255Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
3256first module.
3257ETEXI
3258
3259DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
3260    "-dtb    file    use 'file' as device tree image\n", QEMU_ARCH_ALL)
3261STEXI
3262@item -dtb @var{file}
3263@findex -dtb
3264Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
3265on boot.
3266ETEXI
3267
3268STEXI
3269@end table
3270ETEXI
3271DEFHEADING()
3272
3273DEFHEADING(Debug/Expert options:)
3274STEXI
3275@table @option
3276ETEXI
3277
3278DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
3279    "-fw_cfg [name=]<name>,file=<file>\n"
3280    "                add named fw_cfg entry with contents from file\n"
3281    "-fw_cfg [name=]<name>,string=<str>\n"
3282    "                add named fw_cfg entry with contents from string\n",
3283    QEMU_ARCH_ALL)
3284STEXI
3285
3286@item -fw_cfg [name=]@var{name},file=@var{file}
3287@findex -fw_cfg
3288Add named fw_cfg entry with contents from file @var{file}.
3289
3290@item -fw_cfg [name=]@var{name},string=@var{str}
3291Add named fw_cfg entry with contents from string @var{str}.
3292
3293The terminating NUL character of the contents of @var{str} will not be
3294included as part of the fw_cfg item data. To insert contents with
3295embedded NUL characters, you have to use the @var{file} parameter.
3296
3297The fw_cfg entries are passed by QEMU through to the guest.
3298
3299Example:
3300@example
3301    -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3302@end example
3303creates an fw_cfg entry named opt/com.mycompany/blob with contents
3304from ./my_blob.bin.
3305
3306ETEXI
3307
3308DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3309    "-serial dev     redirect the serial port to char device 'dev'\n",
3310    QEMU_ARCH_ALL)
3311STEXI
3312@item -serial @var{dev}
3313@findex -serial
3314Redirect the virtual serial port to host character device
3315@var{dev}. The default device is @code{vc} in graphical mode and
3316@code{stdio} in non graphical mode.
3317
3318This option can be used several times to simulate up to 4 serial
3319ports.
3320
3321Use @code{-serial none} to disable all serial ports.
3322
3323Available character devices are:
3324@table @option
3325@item vc[:@var{W}x@var{H}]
3326Virtual console. Optionally, a width and height can be given in pixel with
3327@example
3328vc:800x600
3329@end example
3330It is also possible to specify width or height in characters:
3331@example
3332vc:80Cx24C
3333@end example
3334@item pty
3335[Linux only] Pseudo TTY (a new PTY is automatically allocated)
3336@item none
3337No device is allocated.
3338@item null
3339void device
3340@item chardev:@var{id}
3341Use a named character device defined with the @code{-chardev} option.
3342@item /dev/XXX
3343[Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3344parameters are set according to the emulated ones.
3345@item /dev/parport@var{N}
3346[Linux only, parallel port only] Use host parallel port
3347@var{N}. Currently SPP and EPP parallel port features can be used.
3348@item file:@var{filename}
3349Write output to @var{filename}. No character can be read.
3350@item stdio
3351[Unix only] standard input/output
3352@item pipe:@var{filename}
3353name pipe @var{filename}
3354@item COM@var{n}
3355[Windows only] Use host serial port @var{n}
3356@item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3357This implements UDP Net Console.
3358When @var{remote_host} or @var{src_ip} are not specified
3359they default to @code{0.0.0.0}.
3360When not using a specified @var{src_port} a random port is automatically chosen.
3361
3362If you just want a simple readonly console you can use @code{netcat} or
3363@code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3364@code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3365will appear in the netconsole session.
3366
3367If you plan to send characters back via netconsole or you want to stop
3368and start QEMU a lot of times, you should have QEMU use the same
3369source port each time by using something like @code{-serial
3370udp::4555@@:4556} to QEMU. Another approach is to use a patched
3371version of netcat which can listen to a TCP port and send and receive
3372characters via udp.  If you have a patched version of netcat which
3373activates telnet remote echo and single char transfer, then you can
3374use the following options to set up a netcat redirector to allow
3375telnet on port 5555 to access the QEMU port.
3376@table @code
3377@item QEMU Options:
3378-serial udp::4555@@:4556
3379@item netcat options:
3380-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3381@item telnet options:
3382localhost 5555
3383@end table
3384
3385@item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3386The TCP Net Console has two modes of operation.  It can send the serial
3387I/O to a location or wait for a connection from a location.  By default
3388the TCP Net Console is sent to @var{host} at the @var{port}.  If you use
3389the @var{server} option QEMU will wait for a client socket application
3390to connect to the port before continuing, unless the @code{nowait}
3391option was specified.  The @code{nodelay} option disables the Nagle buffering
3392algorithm.  The @code{reconnect} option only applies if @var{noserver} is
3393set, if the connection goes down it will attempt to reconnect at the
3394given interval.  If @var{host} is omitted, 0.0.0.0 is assumed. Only
3395one TCP connection at a time is accepted. You can use @code{telnet} to
3396connect to the corresponding character device.
3397@table @code
3398@item Example to send tcp console to 192.168.0.2 port 4444
3399-serial tcp:192.168.0.2:4444
3400@item Example to listen and wait on port 4444 for connection
3401-serial tcp::4444,server
3402@item Example to not wait and listen on ip 192.168.0.100 port 4444
3403-serial tcp:192.168.0.100:4444,server,nowait
3404@end table
3405
3406@item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3407The telnet protocol is used instead of raw tcp sockets.  The options
3408work the same as if you had specified @code{-serial tcp}.  The
3409difference is that the port acts like a telnet server or client using
3410telnet option negotiation.  This will also allow you to send the
3411MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3412sequence.  Typically in unix telnet you do it with Control-] and then
3413type "send break" followed by pressing the enter key.
3414
3415@item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
3416The WebSocket protocol is used instead of raw tcp socket. The port acts as
3417a WebSocket server. Client mode is not supported.
3418
3419@item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3420A unix domain socket is used instead of a tcp socket.  The option works the
3421same as if you had specified @code{-serial tcp} except the unix domain socket
3422@var{path} is used for connections.
3423
3424@item mon:@var{dev_string}
3425This is a special option to allow the monitor to be multiplexed onto
3426another serial port.  The monitor is accessed with key sequence of
3427@key{Control-a} and then pressing @key{c}.
3428@var{dev_string} should be any one of the serial devices specified
3429above.  An example to multiplex the monitor onto a telnet server
3430listening on port 4444 would be:
3431@table @code
3432@item -serial mon:telnet::4444,server,nowait
3433@end table
3434When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3435QEMU any more but will be passed to the guest instead.
3436
3437@item braille
3438Braille device.  This will use BrlAPI to display the braille output on a real
3439or fake device.
3440
3441@item msmouse
3442Three button serial mouse. Configure the guest to use Microsoft protocol.
3443@end table
3444ETEXI
3445
3446DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3447    "-parallel dev   redirect the parallel port to char device 'dev'\n",
3448    QEMU_ARCH_ALL)
3449STEXI
3450@item -parallel @var{dev}
3451@findex -parallel
3452Redirect the virtual parallel port to host device @var{dev} (same
3453devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3454be used to use hardware devices connected on the corresponding host
3455parallel port.
3456
3457This option can be used several times to simulate up to 3 parallel
3458ports.
3459
3460Use @code{-parallel none} to disable all parallel ports.
3461ETEXI
3462
3463DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3464    "-monitor dev    redirect the monitor to char device 'dev'\n",
3465    QEMU_ARCH_ALL)
3466STEXI
3467@item -monitor @var{dev}
3468@findex -monitor
3469Redirect the monitor to host device @var{dev} (same devices as the
3470serial port).
3471The default device is @code{vc} in graphical mode and @code{stdio} in
3472non graphical mode.
3473Use @code{-monitor none} to disable the default monitor.
3474ETEXI
3475DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3476    "-qmp dev        like -monitor but opens in 'control' mode\n",
3477    QEMU_ARCH_ALL)
3478STEXI
3479@item -qmp @var{dev}
3480@findex -qmp
3481Like -monitor but opens in 'control' mode.
3482ETEXI
3483DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3484    "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3485    QEMU_ARCH_ALL)
3486STEXI
3487@item -qmp-pretty @var{dev}
3488@findex -qmp-pretty
3489Like -qmp but uses pretty JSON formatting.
3490ETEXI
3491
3492DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3493    "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3494STEXI
3495@item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]
3496@findex -mon
3497Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing
3498easing human reading and debugging.
3499ETEXI
3500
3501DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3502    "-debugcon dev   redirect the debug console to char device 'dev'\n",
3503    QEMU_ARCH_ALL)
3504STEXI
3505@item -debugcon @var{dev}
3506@findex -debugcon
3507Redirect the debug console to host device @var{dev} (same devices as the
3508serial port).  The debug console is an I/O port which is typically port
35090xe9; writing to that I/O port sends output to this device.
3510The default device is @code{vc} in graphical mode and @code{stdio} in
3511non graphical mode.
3512ETEXI
3513
3514DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3515    "-pidfile file   write PID to 'file'\n", QEMU_ARCH_ALL)
3516STEXI
3517@item -pidfile @var{file}
3518@findex -pidfile
3519Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3520from a script.
3521ETEXI
3522
3523DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3524    "-singlestep     always run in singlestep mode\n", QEMU_ARCH_ALL)
3525STEXI
3526@item -singlestep
3527@findex -singlestep
3528Run the emulation in single step mode.
3529ETEXI
3530
3531DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3532    "--preconfig     pause QEMU before machine is initialized (experimental)\n",
3533    QEMU_ARCH_ALL)
3534STEXI
3535@item --preconfig
3536@findex --preconfig
3537Pause QEMU for interactive configuration before the machine is created,
3538which allows querying and configuring properties that will affect
3539machine initialization.  Use QMP command 'x-exit-preconfig' to exit
3540the preconfig state and move to the next state (i.e. run guest if -S
3541isn't used or pause the second time if -S is used).  This option is
3542experimental.
3543ETEXI
3544
3545DEF("S", 0, QEMU_OPTION_S, \
3546    "-S              freeze CPU at startup (use 'c' to start execution)\n",
3547    QEMU_ARCH_ALL)
3548STEXI
3549@item -S
3550@findex -S
3551Do not start CPU at startup (you must type 'c' in the monitor).
3552ETEXI
3553
3554DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
3555    "-realtime [mlock=on|off]\n"
3556    "                run qemu with realtime features\n"
3557    "                mlock=on|off controls mlock support (default: on)\n",
3558    QEMU_ARCH_ALL)
3559STEXI
3560@item -realtime mlock=on|off
3561@findex -realtime
3562Run qemu with realtime features.
3563mlocking qemu and guest memory can be enabled via @option{mlock=on}
3564(enabled by default).
3565ETEXI
3566
3567DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3568    "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3569    "                run qemu with overcommit hints\n"
3570    "                mem-lock=on|off controls memory lock support (default: off)\n"
3571    "                cpu-pm=on|off controls cpu power management (default: off)\n",
3572    QEMU_ARCH_ALL)
3573STEXI
3574@item -overcommit mem-lock=on|off
3575@item -overcommit cpu-pm=on|off
3576@findex -overcommit
3577Run qemu with hints about host resource overcommit. The default is
3578to assume that host overcommits all resources.
3579
3580Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3581by default).  This works when host memory is not overcommitted and reduces the
3582worst-case latency for guest.  This is equivalent to @option{realtime}.
3583
3584Guest ability to manage power state of host cpus (increasing latency for other
3585processes on the same host cpu, but decreasing latency for guest) can be
3586enabled via @option{cpu-pm=on} (disabled by default).  This works best when
3587host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3588utilization will be incorrect, not taking into account guest idle time.
3589ETEXI
3590
3591DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3592    "-gdb dev        wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
3593STEXI
3594@item -gdb @var{dev}
3595@findex -gdb
3596Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3597connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3598stdio are reasonable use case. The latter is allowing to start QEMU from
3599within gdb and establish the connection via a pipe:
3600@example
3601(gdb) target remote | exec qemu-system-i386 -gdb stdio ...
3602@end example
3603ETEXI
3604
3605DEF("s", 0, QEMU_OPTION_s, \
3606    "-s              shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3607    QEMU_ARCH_ALL)
3608STEXI
3609@item -s
3610@findex -s
3611Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3612(@pxref{gdb_usage}).
3613ETEXI
3614
3615DEF("d", HAS_ARG, QEMU_OPTION_d, \
3616    "-d item1,...    enable logging of specified items (use '-d help' for a list of log items)\n",
3617    QEMU_ARCH_ALL)
3618STEXI
3619@item -d @var{item1}[,...]
3620@findex -d
3621Enable logging of specified items. Use '-d help' for a list of log items.
3622ETEXI
3623
3624DEF("D", HAS_ARG, QEMU_OPTION_D, \
3625    "-D logfile      output log to logfile (default stderr)\n",
3626    QEMU_ARCH_ALL)
3627STEXI
3628@item -D @var{logfile}
3629@findex -D
3630Output log in @var{logfile} instead of to stderr
3631ETEXI
3632
3633DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3634    "-dfilter range,..  filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3635    QEMU_ARCH_ALL)
3636STEXI
3637@item -dfilter @var{range1}[,...]
3638@findex -dfilter
3639Filter debug output to that relevant to a range of target addresses. The filter
3640spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3641@var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3642addresses and sizes required. For example:
3643@example
3644    -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3645@end example
3646Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3647the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3648block starting at 0xffffffc00005f000.
3649ETEXI
3650
3651DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
3652    "-seed number       seed the pseudo-random number generator\n",
3653    QEMU_ARCH_ALL)
3654STEXI
3655@item -seed @var{number}
3656@findex -seed
3657Force the guest to use a deterministic pseudo-random number generator, seeded
3658with @var{number}.  This does not affect crypto routines within the host.
3659ETEXI
3660
3661DEF("L", HAS_ARG, QEMU_OPTION_L, \
3662    "-L path         set the directory for the BIOS, VGA BIOS and keymaps\n",
3663    QEMU_ARCH_ALL)
3664STEXI
3665@item -L  @var{path}
3666@findex -L
3667Set the directory for the BIOS, VGA BIOS and keymaps.
3668
3669To list all the data directories, use @code{-L help}.
3670ETEXI
3671
3672DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3673    "-bios file      set the filename for the BIOS\n", QEMU_ARCH_ALL)
3674STEXI
3675@item -bios @var{file}
3676@findex -bios
3677Set the filename for the BIOS.
3678ETEXI
3679
3680DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3681    "-enable-kvm     enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3682STEXI
3683@item -enable-kvm
3684@findex -enable-kvm
3685Enable KVM full virtualization support. This option is only available
3686if KVM support is enabled when compiling.
3687ETEXI
3688
3689DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3690    "-xen-domid id   specify xen guest domain id\n", QEMU_ARCH_ALL)
3691DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3692    "-xen-attach     attach to existing xen domain\n"
3693    "                libxl will use this when starting QEMU\n",
3694    QEMU_ARCH_ALL)
3695DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3696    "-xen-domid-restrict     restrict set of available xen operations\n"
3697    "                        to specified domain id. (Does not affect\n"
3698    "                        xenpv machine type).\n",
3699    QEMU_ARCH_ALL)
3700STEXI
3701@item -xen-domid @var{id}
3702@findex -xen-domid
3703Specify xen guest domain @var{id} (XEN only).
3704@item -xen-attach
3705@findex -xen-attach
3706Attach to existing xen domain.
3707libxl will use this when starting QEMU (XEN only).
3708@findex -xen-domid-restrict
3709Restrict set of available xen operations to specified domain id (XEN only).
3710ETEXI
3711
3712DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3713    "-no-reboot      exit instead of rebooting\n", QEMU_ARCH_ALL)
3714STEXI
3715@item -no-reboot
3716@findex -no-reboot
3717Exit instead of rebooting.
3718ETEXI
3719
3720DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3721    "-no-shutdown    stop before shutdown\n", QEMU_ARCH_ALL)
3722STEXI
3723@item -no-shutdown
3724@findex -no-shutdown
3725Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3726This allows for instance switching to monitor to commit changes to the
3727disk image.
3728ETEXI
3729
3730DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
3731    "-loadvm [tag|id]\n" \
3732    "                start right away with a saved state (loadvm in monitor)\n",
3733    QEMU_ARCH_ALL)
3734STEXI
3735@item -loadvm @var{file}
3736@findex -loadvm
3737Start right away with a saved state (@code{loadvm} in monitor)
3738ETEXI
3739
3740#ifndef _WIN32
3741DEF("daemonize", 0, QEMU_OPTION_daemonize, \
3742    "-daemonize      daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
3743#endif
3744STEXI
3745@item -daemonize
3746@findex -daemonize
3747Daemonize the QEMU process after initialization.  QEMU will not detach from
3748standard IO until it is ready to receive connections on any of its devices.
3749This option is a useful way for external programs to launch QEMU without having
3750to cope with initialization race conditions.
3751ETEXI
3752
3753DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
3754    "-option-rom rom load a file, rom, into the option ROM space\n",
3755    QEMU_ARCH_ALL)
3756STEXI
3757@item -option-rom @var{file}
3758@findex -option-rom
3759Load the contents of @var{file} as an option ROM.
3760This option is useful to load things like EtherBoot.
3761ETEXI
3762
3763DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
3764    "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
3765    "                set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
3766    QEMU_ARCH_ALL)
3767
3768STEXI
3769
3770@item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew]
3771@findex -rtc
3772Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3773UTC or local time, respectively. @code{localtime} is required for correct date in
3774MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the
3775format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3776
3777By default the RTC is driven by the host system time. This allows using of the
3778RTC as accurate reference clock inside the guest, specifically if the host
3779time is smoothly following an accurate external reference clock, e.g. via NTP.
3780If you want to isolate the guest time from the host, you can set @option{clock}
3781to @code{rt} instead, which provides a host monotonic clock if host support it.
3782To even prevent the RTC from progressing during suspension, you can set @option{clock}
3783to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in
3784icount mode in order to preserve determinism; however, note that in icount mode
3785the speed of the virtual clock is variable and can in general differ from the
3786host clock.
3787
3788Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3789specifically with Windows' ACPI HAL. This option will try to figure out how
3790many timer interrupts were not processed by the Windows guest and will
3791re-inject them.
3792ETEXI
3793
3794DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
3795    "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \
3796    "                enable virtual instruction counter with 2^N clock ticks per\n" \
3797    "                instruction, enable aligning the host and virtual clocks\n" \
3798    "                or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
3799STEXI
3800@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3801@findex -icount
3802Enable virtual instruction counter.  The virtual cpu will execute one
3803instruction every 2^@var{N} ns of virtual time.  If @code{auto} is specified
3804then the virtual cpu speed will be automatically adjusted to keep virtual
3805time within a few seconds of real time.
3806
3807When the virtual cpu is sleeping, the virtual time will advance at default
3808speed unless @option{sleep=on|off} is specified.
3809With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3810instantly whenever the virtual cpu goes to sleep mode and will not advance
3811if no timer is enabled. This behavior give deterministic execution times from
3812the guest point of view.
3813
3814Note that while this option can give deterministic behavior, it does not
3815provide cycle accurate emulation.  Modern CPUs contain superscalar out of
3816order cores with complex cache hierarchies.  The number of instructions
3817executed often has little or no correlation with actual performance.
3818
3819@option{align=on} will activate the delay algorithm which will try
3820to synchronise the host clock and the virtual clock. The goal is to
3821have a guest running at the real frequency imposed by the shift option.
3822Whenever the guest clock is behind the host clock and if
3823@option{align=on} is specified then we print a message to the user
3824to inform about the delay.
3825Currently this option does not work when @option{shift} is @code{auto}.
3826Note: The sync algorithm will work for those shift values for which
3827the guest clock runs ahead of the host clock. Typically this happens
3828when the shift value is high (how high depends on the host machine).
3829
3830When @option{rr} option is specified deterministic record/replay is enabled.
3831Replay log is written into @var{filename} file in record mode and
3832read from this file in replay mode.
3833
3834Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3835at the start of execution recording. In replay mode this option is used
3836to load the initial VM state.
3837ETEXI
3838
3839DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
3840    "-watchdog model\n" \
3841    "                enable virtual hardware watchdog [default=none]\n",
3842    QEMU_ARCH_ALL)
3843STEXI
3844@item -watchdog @var{model}
3845@findex -watchdog
3846Create a virtual hardware watchdog device.  Once enabled (by a guest
3847action), the watchdog must be periodically polled by an agent inside
3848the guest or else the guest will be restarted. Choose a model for
3849which your guest has drivers.
3850
3851The @var{model} is the model of hardware watchdog to emulate. Use
3852@code{-watchdog help} to list available hardware models. Only one
3853watchdog can be enabled for a guest.
3854
3855The following models may be available:
3856@table @option
3857@item ib700
3858iBASE 700 is a very simple ISA watchdog with a single timer.
3859@item i6300esb
3860Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3861dual-timer watchdog.
3862@item diag288
3863A virtual watchdog for s390x backed by the diagnose 288 hypercall
3864(currently KVM only).
3865@end table
3866ETEXI
3867
3868DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
3869    "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
3870    "                action when watchdog fires [default=reset]\n",
3871    QEMU_ARCH_ALL)
3872STEXI
3873@item -watchdog-action @var{action}
3874@findex -watchdog-action
3875
3876The @var{action} controls what QEMU will do when the watchdog timer
3877expires.
3878The default is
3879@code{reset} (forcefully reset the guest).
3880Other possible actions are:
3881@code{shutdown} (attempt to gracefully shutdown the guest),
3882@code{poweroff} (forcefully poweroff the guest),
3883@code{inject-nmi} (inject a NMI into the guest),
3884@code{pause} (pause the guest),
3885@code{debug} (print a debug message and continue), or
3886@code{none} (do nothing).
3887
3888Note that the @code{shutdown} action requires that the guest responds
3889to ACPI signals, which it may not be able to do in the sort of
3890situations where the watchdog would have expired, and thus
3891@code{-watchdog-action shutdown} is not recommended for production use.
3892
3893Examples:
3894
3895@table @code
3896@item -watchdog i6300esb -watchdog-action pause
3897@itemx -watchdog ib700
3898@end table
3899ETEXI
3900
3901DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
3902    "-echr chr       set terminal escape character instead of ctrl-a\n",
3903    QEMU_ARCH_ALL)
3904STEXI
3905
3906@item -echr @var{numeric_ascii_value}
3907@findex -echr
3908Change the escape character used for switching to the monitor when using
3909monitor and serial sharing.  The default is @code{0x01} when using the
3910@code{-nographic} option.  @code{0x01} is equal to pressing
3911@code{Control-a}.  You can select a different character from the ascii
3912control keys where 1 through 26 map to Control-a through Control-z.  For
3913instance you could use the either of the following to change the escape
3914character to Control-t.
3915@table @code
3916@item -echr 0x14
3917@itemx -echr 20
3918@end table
3919ETEXI
3920
3921DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
3922    "-show-cursor    show cursor\n", QEMU_ARCH_ALL)
3923STEXI
3924@item -show-cursor
3925@findex -show-cursor
3926Show cursor.
3927ETEXI
3928
3929DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
3930    "-tb-size n      set TB size\n", QEMU_ARCH_ALL)
3931STEXI
3932@item -tb-size @var{n}
3933@findex -tb-size
3934Set TB size.
3935ETEXI
3936
3937DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
3938    "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \
3939    "-incoming rdma:host:port[,ipv4][,ipv6]\n" \
3940    "-incoming unix:socketpath\n" \
3941    "                prepare for incoming migration, listen on\n" \
3942    "                specified protocol and socket address\n" \
3943    "-incoming fd:fd\n" \
3944    "-incoming exec:cmdline\n" \
3945    "                accept incoming migration on given file descriptor\n" \
3946    "                or from given external command\n" \
3947    "-incoming defer\n" \
3948    "                wait for the URI to be specified via migrate_incoming\n",
3949    QEMU_ARCH_ALL)
3950STEXI
3951@item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
3952@itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
3953@findex -incoming
3954Prepare for incoming migration, listen on a given tcp port.
3955
3956@item -incoming unix:@var{socketpath}
3957Prepare for incoming migration, listen on a given unix socket.
3958
3959@item -incoming fd:@var{fd}
3960Accept incoming migration from a given filedescriptor.
3961
3962@item -incoming exec:@var{cmdline}
3963Accept incoming migration as an output from specified external command.
3964
3965@item -incoming defer
3966Wait for the URI to be specified via migrate_incoming.  The monitor can
3967be used to change settings (such as migration parameters) prior to issuing
3968the migrate_incoming to allow the migration to begin.
3969ETEXI
3970
3971DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
3972    "-only-migratable     allow only migratable devices\n", QEMU_ARCH_ALL)
3973STEXI
3974@item -only-migratable
3975@findex -only-migratable
3976Only allow migratable devices. Devices will not be allowed to enter an
3977unmigratable state.
3978ETEXI
3979
3980DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
3981    "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
3982STEXI
3983@item -nodefaults
3984@findex -nodefaults
3985Don't create default devices. Normally, QEMU sets the default devices like serial
3986port, parallel port, virtual console, monitor device, VGA adapter, floppy and
3987CD-ROM drive and others. The @code{-nodefaults} option will disable all those
3988default devices.
3989ETEXI
3990
3991#ifndef _WIN32
3992DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
3993    "-chroot dir     chroot to dir just before starting the VM\n",
3994    QEMU_ARCH_ALL)
3995#endif
3996STEXI
3997@item -chroot @var{dir}
3998@findex -chroot
3999Immediately before starting guest execution, chroot to the specified
4000directory.  Especially useful in combination with -runas.
4001ETEXI
4002
4003#ifndef _WIN32
4004DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
4005    "-runas user     change to user id user just before starting the VM\n" \
4006    "                user can be numeric uid:gid instead\n",
4007    QEMU_ARCH_ALL)
4008#endif
4009STEXI
4010@item -runas @var{user}
4011@findex -runas
4012Immediately before starting guest execution, drop root privileges, switching
4013to the specified user.
4014ETEXI
4015
4016DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
4017    "-prom-env variable=value\n"
4018    "                set OpenBIOS nvram variables\n",
4019    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
4020STEXI
4021@item -prom-env @var{variable}=@var{value}
4022@findex -prom-env
4023Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
4024ETEXI
4025DEF("semihosting", 0, QEMU_OPTION_semihosting,
4026    "-semihosting    semihosting mode\n",
4027    QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4028    QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4029STEXI
4030@item -semihosting
4031@findex -semihosting
4032Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
4033ETEXI
4034DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
4035    "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
4036    "                semihosting configuration\n",
4037QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
4038QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
4039STEXI
4040@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]
4041@findex -semihosting-config
4042Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II only).
4043@table @option
4044@item target=@code{native|gdb|auto}
4045Defines where the semihosting calls will be addressed, to QEMU (@code{native})
4046or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
4047during debug sessions and @code{native} otherwise.
4048@item chardev=@var{str1}
4049Send the output to a chardev backend output for native or auto output when not in gdb
4050@item arg=@var{str1},arg=@var{str2},...
4051Allows the user to pass input arguments, and can be used multiple times to build
4052up a list. The old-style @code{-kernel}/@code{-append} method of passing a
4053command line is still supported for backward compatibility. If both the
4054@code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
4055specified, the former is passed to semihosting as it always takes precedence.
4056@end table
4057ETEXI
4058DEF("old-param", 0, QEMU_OPTION_old_param,
4059    "-old-param      old param mode\n", QEMU_ARCH_ARM)
4060STEXI
4061@item -old-param
4062@findex -old-param (ARM)
4063Old param mode (ARM only).
4064ETEXI
4065
4066DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
4067    "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
4068    "          [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
4069    "                Enable seccomp mode 2 system call filter (default 'off').\n" \
4070    "                use 'obsolete' to allow obsolete system calls that are provided\n" \
4071    "                    by the kernel, but typically no longer used by modern\n" \
4072    "                    C library implementations.\n" \
4073    "                use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
4074    "                    its privileges by blacklisting all set*uid|gid system calls.\n" \
4075    "                    The value 'children' will deny set*uid|gid system calls for\n" \
4076    "                    main QEMU process but will allow forks and execves to run unprivileged\n" \
4077    "                use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
4078    "                     blacklisting *fork and execve\n" \
4079    "                use 'resourcecontrol' to disable process affinity and schedular priority\n",
4080    QEMU_ARCH_ALL)
4081STEXI
4082@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
4083@findex -sandbox
4084Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
4085disable it.  The default is 'off'.
4086@table @option
4087@item obsolete=@var{string}
4088Enable Obsolete system calls
4089@item elevateprivileges=@var{string}
4090Disable set*uid|gid system calls
4091@item spawn=@var{string}
4092Disable *fork and execve
4093@item resourcecontrol=@var{string}
4094Disable process affinity and schedular priority
4095@end table
4096ETEXI
4097
4098DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
4099    "-readconfig <file>\n", QEMU_ARCH_ALL)
4100STEXI
4101@item -readconfig @var{file}
4102@findex -readconfig
4103Read device configuration from @var{file}. This approach is useful when you want to spawn
4104QEMU process with many command line options but you don't want to exceed the command line
4105character limit.
4106ETEXI
4107DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
4108    "-writeconfig <file>\n"
4109    "                read/write config file\n", QEMU_ARCH_ALL)
4110STEXI
4111@item -writeconfig @var{file}
4112@findex -writeconfig
4113Write device configuration to @var{file}. The @var{file} can be either filename to save
4114command line and device configuration into file or dash @code{-}) character to print the
4115output to stdout. This can be later used as input file for @code{-readconfig} option.
4116ETEXI
4117
4118DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
4119    "-no-user-config\n"
4120    "                do not load default user-provided config files at startup\n",
4121    QEMU_ARCH_ALL)
4122STEXI
4123@item -no-user-config
4124@findex -no-user-config
4125The @code{-no-user-config} option makes QEMU not load any of the user-provided
4126config files on @var{sysconfdir}.
4127ETEXI
4128
4129DEF("trace", HAS_ARG, QEMU_OPTION_trace,
4130    "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
4131    "                specify tracing options\n",
4132    QEMU_ARCH_ALL)
4133STEXI
4134HXCOMM This line is not accurate, as some sub-options are backend-specific but
4135HXCOMM HX does not support conditional compilation of text.
4136@item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
4137@findex -trace
4138@include qemu-option-trace.texi
4139ETEXI
4140
4141HXCOMM Internal use
4142DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
4143DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
4144
4145#ifdef __linux__
4146DEF("enable-fips", 0, QEMU_OPTION_enablefips,
4147    "-enable-fips    enable FIPS 140-2 compliance\n",
4148    QEMU_ARCH_ALL)
4149#endif
4150STEXI
4151@item -enable-fips
4152@findex -enable-fips
4153Enable FIPS 140-2 compliance mode.
4154ETEXI
4155
4156HXCOMM Deprecated by -machine accel=tcg property
4157DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
4158
4159DEF("msg", HAS_ARG, QEMU_OPTION_msg,
4160    "-msg timestamp[=on|off]\n"
4161    "                change the format of messages\n"
4162    "                on|off controls leading timestamps (default:on)\n",
4163    QEMU_ARCH_ALL)
4164STEXI
4165@item -msg timestamp[=on|off]
4166@findex -msg
4167prepend a timestamp to each log message.(default:on)
4168ETEXI
4169
4170DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
4171    "-dump-vmstate <file>\n"
4172    "                Output vmstate information in JSON format to file.\n"
4173    "                Use the scripts/vmstate-static-checker.py file to\n"
4174    "                check for possible regressions in migration code\n"
4175    "                by comparing two such vmstate dumps.\n",
4176    QEMU_ARCH_ALL)
4177STEXI
4178@item -dump-vmstate @var{file}
4179@findex -dump-vmstate
4180Dump json-encoded vmstate information for current machine type to file
4181in @var{file}
4182ETEXI
4183
4184DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
4185    "-enable-sync-profile\n"
4186    "                enable synchronization profiling\n",
4187    QEMU_ARCH_ALL)
4188STEXI
4189@item -enable-sync-profile
4190@findex -enable-sync-profile
4191Enable synchronization profiling.
4192ETEXI
4193
4194STEXI
4195@end table
4196ETEXI
4197DEFHEADING()
4198
4199DEFHEADING(Generic object creation:)
4200STEXI
4201@table @option
4202ETEXI
4203
4204DEF("object", HAS_ARG, QEMU_OPTION_object,
4205    "-object TYPENAME[,PROP1=VALUE1,...]\n"
4206    "                create a new object of type TYPENAME setting properties\n"
4207    "                in the order they are specified.  Note that the 'id'\n"
4208    "                property must be set.  These objects are placed in the\n"
4209    "                '/objects' path.\n",
4210    QEMU_ARCH_ALL)
4211STEXI
4212@item -object @var{typename}[,@var{prop1}=@var{value1},...]
4213@findex -object
4214Create a new object of type @var{typename} setting properties
4215in the order they are specified.  Note that the 'id'
4216property must be set.  These objects are placed in the
4217'/objects' path.
4218
4219@table @option
4220
4221@item -object memory-backend-file,id=@var{id},size=@var{size},mem-path=@var{dir},share=@var{on|off},discard-data=@var{on|off},merge=@var{on|off},dump=@var{on|off},prealloc=@var{on|off},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},align=@var{align}
4222
4223Creates a memory file backend object, which can be used to back
4224the guest RAM with huge pages.
4225
4226The @option{id} parameter is a unique ID that will be used to reference this
4227memory region when configuring the @option{-numa} argument.
4228
4229The @option{size} option provides the size of the memory region, and accepts
4230common suffixes, eg @option{500M}.
4231
4232The @option{mem-path} provides the path to either a shared memory or huge page
4233filesystem mount.
4234
4235The @option{share} boolean option determines whether the memory
4236region is marked as private to QEMU, or shared. The latter allows
4237a co-operating external process to access the QEMU memory region.
4238
4239The @option{share} is also required for pvrdma devices due to
4240limitations in the RDMA API provided by Linux.
4241
4242Setting share=on might affect the ability to configure NUMA
4243bindings for the memory backend under some circumstances, see
4244Documentation/vm/numa_memory_policy.txt on the Linux kernel
4245source tree for additional details.
4246
4247Setting the @option{discard-data} boolean option to @var{on}
4248indicates that file contents can be destroyed when QEMU exits,
4249to avoid unnecessarily flushing data to the backing file.  Note
4250that @option{discard-data} is only an optimization, and QEMU
4251might not discard file contents if it aborts unexpectedly or is
4252terminated using SIGKILL.
4253
4254The @option{merge} boolean option enables memory merge, also known as
4255MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
4256memory deduplication.
4257
4258Setting the @option{dump} boolean option to @var{off} excludes the memory from
4259core dumps. This feature is also known as MADV_DONTDUMP.
4260
4261The @option{prealloc} boolean option enables memory preallocation.
4262
4263The @option{host-nodes} option binds the memory range to a list of NUMA host
4264nodes.
4265
4266The @option{policy} option sets the NUMA policy to one of the following values:
4267
4268@table @option
4269@item @var{default}
4270default host policy
4271
4272@item @var{preferred}
4273prefer the given host node list for allocation
4274
4275@item @var{bind}
4276restrict memory allocation to the given host node list
4277
4278@item @var{interleave}
4279interleave memory allocations across the given host node list
4280@end table
4281
4282The @option{align} option specifies the base address alignment when
4283QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4284@option{2M}. Some backend store specified by @option{mem-path}
4285requires an alignment different than the default one used by QEMU, eg
4286the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4287such cases, users can specify the required alignment via this option.
4288
4289The @option{pmem} option specifies whether the backing file specified
4290by @option{mem-path} is in host persistent memory that can be accessed
4291using the SNIA NVM programming model (e.g. Intel NVDIMM).
4292If @option{pmem} is set to 'on', QEMU will take necessary operations to
4293guarantee the persistence of its own writes to @option{mem-path}
4294(e.g. in vNVDIMM label emulation and live migration).
4295Also, we will map the backend-file with MAP_SYNC flag, which ensures the
4296file metadata is in sync for @option{mem-path} in case of host crash
4297or a power failure. MAP_SYNC requires support from both the host kernel
4298(since Linux kernel 4.15) and the filesystem of @option{mem-path} mounted
4299with DAX option.
4300
4301@item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave}
4302
4303Creates a memory backend object, which can be used to back the guest RAM.
4304Memory backend objects offer more control than the @option{-m} option that is
4305traditionally used to define guest RAM. Please refer to
4306@option{memory-backend-file} for a description of the options.
4307
4308@item -object memory-backend-memfd,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},seal=@var{on|off},hugetlb=@var{on|off},hugetlbsize=@var{size}
4309
4310Creates an anonymous memory file backend object, which allows QEMU to
4311share the memory with an external process (e.g. when using
4312vhost-user). The memory is allocated with memfd and optional
4313sealing. (Linux only)
4314
4315The @option{seal} option creates a sealed-file, that will block
4316further resizing the memory ('on' by default).
4317
4318The @option{hugetlb} option specify the file to be created resides in
4319the hugetlbfs filesystem (since Linux 4.14).  Used in conjunction with
4320the @option{hugetlb} option, the @option{hugetlbsize} option specify
4321the hugetlb page size on systems that support multiple hugetlb page
4322sizes (it must be a power of 2 value supported by the system).
4323
4324In some versions of Linux, the @option{hugetlb} option is incompatible
4325with the @option{seal} option (requires at least Linux 4.16).
4326
4327Please refer to @option{memory-backend-file} for a description of the
4328other options.
4329
4330The @option{share} boolean option is @var{on} by default with memfd.
4331
4332@item -object rng-random,id=@var{id},filename=@var{/dev/random}
4333
4334Creates a random number generator backend which obtains entropy from
4335a device on the host. The @option{id} parameter is a unique ID that
4336will be used to reference this entropy backend from the @option{virtio-rng}
4337device. The @option{filename} parameter specifies which file to obtain
4338entropy from and if omitted defaults to @option{/dev/urandom}.
4339
4340@item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4341
4342Creates a random number generator backend which obtains entropy from
4343an external daemon running on the host. The @option{id} parameter is
4344a unique ID that will be used to reference this entropy backend from
4345the @option{virtio-rng} device. The @option{chardev} parameter is
4346the unique ID of a character device backend that provides the connection
4347to the RNG daemon.
4348
4349@item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4350
4351Creates a TLS anonymous credentials object, which can be used to provide
4352TLS support on network backends. The @option{id} parameter is a unique
4353ID which network backends will use to access the credentials. The
4354@option{endpoint} is either @option{server} or @option{client} depending
4355on whether the QEMU network backend that uses the credentials will be
4356acting as a client or as a server. If @option{verify-peer} is enabled
4357(the default) then once the handshake is completed, the peer credentials
4358will be verified, though this is a no-op for anonymous credentials.
4359
4360The @var{dir} parameter tells QEMU where to find the credential
4361files. For server endpoints, this directory may contain a file
4362@var{dh-params.pem} providing diffie-hellman parameters to use
4363for the TLS server. If the file is missing, QEMU will generate
4364a set of DH parameters at startup. This is a computationally
4365expensive operation that consumes random pool entropy, so it is
4366recommended that a persistent set of parameters be generated
4367upfront and saved.
4368
4369@item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4370
4371Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4372TLS support on network backends. The @option{id} parameter is a unique
4373ID which network backends will use to access the credentials. The
4374@option{endpoint} is either @option{server} or @option{client} depending
4375on whether the QEMU network backend that uses the credentials will be
4376acting as a client or as a server. For clients only, @option{username}
4377is the username which will be sent to the server.  If omitted
4378it defaults to ``qemu''.
4379
4380The @var{dir} parameter tells QEMU where to find the keys file.
4381It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4382pairs.  This file can most easily be created using the GnuTLS
4383@code{psktool} program.
4384
4385For server endpoints, @var{dir} may also contain a file
4386@var{dh-params.pem} providing diffie-hellman parameters to use
4387for the TLS server. If the file is missing, QEMU will generate
4388a set of DH parameters at startup. This is a computationally
4389expensive operation that consumes random pool entropy, so it is
4390recommended that a persistent set of parameters be generated
4391up front and saved.
4392
4393@item -object tls-creds-x509,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},priority=@var{priority},verify-peer=@var{on|off},passwordid=@var{id}
4394
4395Creates a TLS anonymous credentials object, which can be used to provide
4396TLS support on network backends. The @option{id} parameter is a unique
4397ID which network backends will use to access the credentials. The
4398@option{endpoint} is either @option{server} or @option{client} depending
4399on whether the QEMU network backend that uses the credentials will be
4400acting as a client or as a server. If @option{verify-peer} is enabled
4401(the default) then once the handshake is completed, the peer credentials
4402will be verified. With x509 certificates, this implies that the clients
4403must be provided with valid client certificates too.
4404
4405The @var{dir} parameter tells QEMU where to find the credential
4406files. For server endpoints, this directory may contain a file
4407@var{dh-params.pem} providing diffie-hellman parameters to use
4408for the TLS server. If the file is missing, QEMU will generate
4409a set of DH parameters at startup. This is a computationally
4410expensive operation that consumes random pool entropy, so it is
4411recommended that a persistent set of parameters be generated
4412upfront and saved.
4413
4414For x509 certificate credentials the directory will contain further files
4415providing the x509 certificates. The certificates must be stored
4416in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4417@var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4418@var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4419
4420For the @var{server-key.pem} and @var{client-key.pem} files which
4421contain sensitive private keys, it is possible to use an encrypted
4422version by providing the @var{passwordid} parameter. This provides
4423the ID of a previously created @code{secret} object containing the
4424password for decryption.
4425
4426The @var{priority} parameter allows to override the global default
4427priority used by gnutls. This can be useful if the system administrator
4428needs to use a weaker set of crypto priorities for QEMU without
4429potentially forcing the weakness onto all applications. Or conversely
4430if one wants wants a stronger default for QEMU than for all other
4431applications, they can do this through this parameter. Its format is
4432a gnutls priority string as described at
4433@url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4434
4435@item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4436
4437Interval @var{t} can't be 0, this filter batches the packet delivery: all
4438packets arriving in a given interval on netdev @var{netdevid} are delayed
4439until the end of the interval. Interval is in microseconds.
4440@option{status} is optional that indicate whether the netfilter is
4441on (enabled) or off (disabled), the default status for netfilter will be 'on'.
4442
4443queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4444
4445@option{all}: the filter is attached both to the receive and the transmit
4446              queue of the netdev (default).
4447
4448@option{rx}: the filter is attached to the receive queue of the netdev,
4449             where it will receive packets sent to the netdev.
4450
4451@option{tx}: the filter is attached to the transmit queue of the netdev,
4452             where it will receive packets sent by the netdev.
4453
4454@item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4455
4456filter-mirror on netdev @var{netdevid},mirror net packet to chardev@var{chardevid}, if it has the vnet_hdr_support flag, filter-mirror will mirror packet with vnet_hdr_len.
4457
4458@item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4459
4460filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4461@var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag,
4462filter-redirector will redirect packet with vnet_hdr_len.
4463Create a filter-redirector we need to differ outdev id from indev id, id can not
4464be the same. we can just use indev or outdev, but at least one of indev or outdev
4465need to be specified.
4466
4467@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support]
4468
4469Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4470secondary from primary to keep secondary tcp connection,and rewrite
4471tcp packet to primary from secondary make tcp packet can be handled by
4472client.if it has the vnet_hdr_support flag, we can parse packet with vnet header.
4473
4474usage:
4475colo secondary:
4476-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4477-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4478-object filter-rewriter,id=rew0,netdev=hn0,queue=all
4479
4480@item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4481
4482Dump the network traffic on netdev @var{dev} to the file specified by
4483@var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4484The file format is libpcap, so it can be analyzed with tools such as tcpdump
4485or Wireshark.
4486
4487@item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},outdev=@var{chardevid},iothread=@var{id}[,vnet_hdr_support][,notify_dev=@var{id}]
4488
4489Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4490secondary packet. If the packets are same, we will output primary
4491packet to outdev@var{chardevid}, else we will notify colo-frame
4492do checkpoint and send primary packet to outdev@var{chardevid}.
4493In order to improve efficiency, we need to put the task of comparison
4494in another thread. If it has the vnet_hdr_support flag, colo compare
4495will send/recv packet with vnet_hdr_len.
4496If you want to use Xen COLO, will need the notify_dev to notify Xen
4497colo-frame to do checkpoint.
4498
4499we must use it with the help of filter-mirror and filter-redirector.
4500
4501@example
4502
4503KVM COLO
4504
4505primary:
4506-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4507-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4508-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4509-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4510-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4511-chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4512-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4513-chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4514-object iothread,id=iothread1
4515-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4516-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4517-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4518-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
4519
4520secondary:
4521-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4522-device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4523-chardev socket,id=red0,host=3.3.3.3,port=9003
4524-chardev socket,id=red1,host=3.3.3.3,port=9004
4525-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4526-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4527
4528
4529Xen COLO
4530
4531primary:
4532-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4533-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4534-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4535-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4536-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4537-chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4538-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4539-chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4540-chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait
4541-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4542-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4543-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4544-object iothread,id=iothread1
4545-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1
4546
4547secondary:
4548-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4549-device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4550-chardev socket,id=red0,host=3.3.3.3,port=9003
4551-chardev socket,id=red1,host=3.3.3.3,port=9004
4552-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4553-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4554
4555@end example
4556
4557If you want to know the detail of above command line, you can read
4558the colo-compare git log.
4559
4560@item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4561
4562Creates a cryptodev backend which executes crypto opreation from
4563the QEMU cipher APIS. The @var{id} parameter is
4564a unique ID that will be used to reference this cryptodev backend from
4565the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4566which specify the queue number of cryptodev backend, the default of
4567@var{queues} is 1.
4568
4569@example
4570
4571 # qemu-system-x86_64 \
4572   [...] \
4573       -object cryptodev-backend-builtin,id=cryptodev0 \
4574       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4575   [...]
4576@end example
4577
4578@item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}]
4579
4580Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}.
4581The @var{id} parameter is a unique ID that will be used to reference this
4582cryptodev backend from the @option{virtio-crypto} device.
4583The chardev should be a unix domain socket backed one. The vhost-user uses
4584a specifically defined protocol to pass vhost ioctl replacement messages
4585to an application on the other end of the socket.
4586The @var{queues} parameter is optional, which specify the queue number
4587of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1.
4588
4589@example
4590
4591 # qemu-system-x86_64 \
4592   [...] \
4593       -chardev socket,id=chardev0,path=/path/to/socket \
4594       -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \
4595       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4596   [...]
4597@end example
4598
4599@item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4600@item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4601
4602Defines a secret to store a password, encryption key, or some other sensitive
4603data. The sensitive data can either be passed directly via the @var{data}
4604parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4605parameter is insecure unless the sensitive data is encrypted.
4606
4607The sensitive data can be provided in raw format (the default), or base64.
4608When encoded as JSON, the raw format only supports valid UTF-8 characters,
4609so base64 is recommended for sending binary data. QEMU will convert from
4610which ever format is provided to the format it needs internally. eg, an
4611RBD password can be provided in raw format, even though it will be base64
4612encoded when passed onto the RBD sever.
4613
4614For added protection, it is possible to encrypt the data associated with
4615a secret using the AES-256-CBC cipher. Use of encryption is indicated
4616by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4617parameter provides the ID of a previously defined secret that contains
4618the AES-256 decryption key. This key should be 32-bytes long and be
4619base64 encoded. The @var{iv} parameter provides the random initialization
4620vector used for encryption of this particular secret and should be a
4621base64 encrypted string of the 16-byte IV.
4622
4623The simplest (insecure) usage is to provide the secret inline
4624
4625@example
4626
4627 # $QEMU -object secret,id=sec0,data=letmein,format=raw
4628
4629@end example
4630
4631The simplest secure usage is to provide the secret via a file
4632
4633 # printf "letmein" > mypasswd.txt
4634 # $QEMU -object secret,id=sec0,file=mypasswd.txt,format=raw
4635
4636For greater security, AES-256-CBC should be used. To illustrate usage,
4637consider the openssl command line tool which can encrypt the data. Note
4638that when encrypting, the plaintext must be padded to the cipher block
4639size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4640
4641First a master key needs to be created in base64 encoding:
4642
4643@example
4644 # openssl rand -base64 32 > key.b64
4645 # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
4646@end example
4647
4648Each secret to be encrypted needs to have a random initialization vector
4649generated. These do not need to be kept secret
4650
4651@example
4652 # openssl rand -base64 16 > iv.b64
4653 # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
4654@end example
4655
4656The secret to be defined can now be encrypted, in this case we're
4657telling openssl to base64 encode the result, but it could be left
4658as raw bytes if desired.
4659
4660@example
4661 # SECRET=$(printf "letmein" |
4662            openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4663@end example
4664
4665When launching QEMU, create a master secret pointing to @code{key.b64}
4666and specify that to be used to decrypt the user password. Pass the
4667contents of @code{iv.b64} to the second secret
4668
4669@example
4670 # $QEMU \
4671     -object secret,id=secmaster0,format=base64,file=key.b64 \
4672     -object secret,id=sec0,keyid=secmaster0,format=base64,\
4673         data=$SECRET,iv=$(<iv.b64)
4674@end example
4675
4676@item -object sev-guest,id=@var{id},cbitpos=@var{cbitpos},reduced-phys-bits=@var{val},[sev-device=@var{string},policy=@var{policy},handle=@var{handle},dh-cert-file=@var{file},session-file=@var{file}]
4677
4678Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4679to provide the guest memory encryption support on AMD processors.
4680
4681When memory encryption is enabled, one of the physical address bit (aka the
4682C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4683is used to provide the C-bit position. The C-bit position is Host family dependent
4684hence user must provide this value. On EPYC, the value should be 47.
4685
4686When memory encryption is enabled, we loose certain bits in physical address space.
4687The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4688physical address space. Similar to C-bit, the value is Host family dependent.
4689On EPYC, the value should be 5.
4690
4691The @option{sev-device} provides the device file to use for communicating with
4692the SEV firmware running inside AMD Secure Processor. The default device is
4693'/dev/sev'. If hardware supports memory encryption then /dev/sev devices are
4694created by CCP driver.
4695
4696The @option{policy} provides the guest policy to be enforced by the SEV firmware
4697and restrict what configuration and operational commands can be performed on this
4698guest by the hypervisor. The policy should be provided by the guest owner and is
4699bound to the guest and cannot be changed throughout the lifetime of the guest.
4700The default is 0.
4701
4702If guest @option{policy} allows sharing the key with another SEV guest then
4703@option{handle} can be use to provide handle of the guest from which to share
4704the key.
4705
4706The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4707Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters
4708are used for establishing a cryptographic session with the guest owner to
4709negotiate keys used for attestation. The file must be encoded in base64.
4710
4711e.g to launch a SEV guest
4712@example
4713 # $QEMU \
4714     ......
4715     -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
4716     -machine ...,memory-encryption=sev0
4717     .....
4718
4719@end example
4720
4721
4722@item -object authz-simple,id=@var{id},identity=@var{string}
4723
4724Create an authorization object that will control access to network services.
4725
4726The @option{identity} parameter is identifies the user and its format
4727depends on the network service that authorization object is associated
4728with. For authorizing based on TLS x509 certificates, the identity must
4729be the x509 distinguished name. Note that care must be taken to escape
4730any commas in the distinguished name.
4731
4732An example authorization object to validate a x509 distinguished name
4733would look like:
4734@example
4735 # $QEMU \
4736     ...
4737     -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \
4738     ...
4739@end example
4740
4741Note the use of quotes due to the x509 distinguished name containing
4742whitespace, and escaping of ','.
4743
4744@item -object authz-listfile,id=@var{id},filename=@var{path},refresh=@var{yes|no}
4745
4746Create an authorization object that will control access to network services.
4747
4748The @option{filename} parameter is the fully qualified path to a file
4749containing the access control list rules in JSON format.
4750
4751An example set of rules that match against SASL usernames might look
4752like:
4753
4754@example
4755  @{
4756    "rules": [
4757       @{ "match": "fred", "policy": "allow", "format": "exact" @},
4758       @{ "match": "bob", "policy": "allow", "format": "exact" @},
4759       @{ "match": "danb", "policy": "deny", "format": "glob" @},
4760       @{ "match": "dan*", "policy": "allow", "format": "exact" @},
4761    ],
4762    "policy": "deny"
4763  @}
4764@end example
4765
4766When checking access the object will iterate over all the rules and
4767the first rule to match will have its @option{policy} value returned
4768as the result. If no rules match, then the default @option{policy}
4769value is returned.
4770
4771The rules can either be an exact string match, or they can use the
4772simple UNIX glob pattern matching to allow wildcards to be used.
4773
4774If @option{refresh} is set to true the file will be monitored
4775and automatically reloaded whenever its content changes.
4776
4777As with the @code{authz-simple} object, the format of the identity
4778strings being matched depends on the network service, but is usually
4779a TLS x509 distinguished name, or a SASL username.
4780
4781An example authorization object to validate a SASL username
4782would look like:
4783@example
4784 # $QEMU \
4785     ...
4786     -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes
4787     ...
4788@end example
4789
4790@item -object authz-pam,id=@var{id},service=@var{string}
4791
4792Create an authorization object that will control access to network services.
4793
4794The @option{service} parameter provides the name of a PAM service to use
4795for authorization. It requires that a file @code{/etc/pam.d/@var{service}}
4796exist to provide the configuration for the @code{account} subsystem.
4797
4798An example authorization object to validate a TLS x509 distinguished
4799name would look like:
4800
4801@example
4802 # $QEMU \
4803     ...
4804     -object authz-pam,id=auth0,service=qemu-vnc
4805     ...
4806@end example
4807
4808There would then be a corresponding config file for PAM at
4809@code{/etc/pam.d/qemu-vnc} that contains:
4810
4811@example
4812account requisite  pam_listfile.so item=user sense=allow \
4813           file=/etc/qemu/vnc.allow
4814@end example
4815
4816Finally the @code{/etc/qemu/vnc.allow} file would contain
4817the list of x509 distingished names that are permitted
4818access
4819
4820@example
4821CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB
4822@end example
4823
4824
4825@end table
4826
4827ETEXI
4828
4829
4830HXCOMM This is the last statement. Insert new options before this line!
4831STEXI
4832@end table
4833ETEXI
4834