xref: /openbmc/qemu/qemu-options.hx (revision 40cf6a54)
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][,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\n"
146    "                threads= number of threads on one CPU core\n"
147    "                sockets= number of discrete sockets in the system\n",
148        QEMU_ARCH_ALL)
149STEXI
150@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
151@findex -smp
152Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
153CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
154to 4.
155For the PC target, the number of @var{cores} per socket, the number
156of @var{threads} per cores and the total number of @var{sockets} can be
157specified. Missing values will be computed. If any on the three values is
158given, the total number of CPUs @var{n} can be omitted. @var{maxcpus}
159specifies the maximum number of hotpluggable CPUs.
160ETEXI
161
162DEF("numa", HAS_ARG, QEMU_OPTION_numa,
163    "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
164    "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
165    "-numa dist,src=source,dst=destination,val=distance\n"
166    "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n",
167    QEMU_ARCH_ALL)
168STEXI
169@item -numa node[,mem=@var{size}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
170@itemx -numa node[,memdev=@var{id}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
171@itemx -numa dist,src=@var{source},dst=@var{destination},val=@var{distance}
172@itemx -numa cpu,node-id=@var{node}[,socket-id=@var{x}][,core-id=@var{y}][,thread-id=@var{z}]
173@findex -numa
174Define a NUMA node and assign RAM and VCPUs to it.
175Set the NUMA distance from a source node to a destination node.
176
177Legacy VCPU assignment uses @samp{cpus} option where
178@var{firstcpu} and @var{lastcpu} are CPU indexes. Each
179@samp{cpus} option represent a contiguous range of CPU indexes
180(or a single VCPU if @var{lastcpu} is omitted). A non-contiguous
181set of VCPUs can be represented by providing multiple @samp{cpus}
182options. If @samp{cpus} is omitted on all nodes, VCPUs are automatically
183split between them.
184
185For example, the following option assigns VCPUs 0, 1, 2 and 5 to
186a NUMA node:
187@example
188-numa node,cpus=0-2,cpus=5
189@end example
190
191@samp{cpu} option is a new alternative to @samp{cpus} option
192which uses @samp{socket-id|core-id|thread-id} properties to assign
193CPU objects to a @var{node} using topology layout properties of CPU.
194The set of properties is machine specific, and depends on used
195machine type/@samp{smp} options. It could be queried with
196@samp{hotpluggable-cpus} monitor command.
197@samp{node-id} property specifies @var{node} to which CPU object
198will be assigned, it's required for @var{node} to be declared
199with @samp{node} option before it's used with @samp{cpu} option.
200
201For example:
202@example
203-M pc \
204-smp 1,sockets=2,maxcpus=2 \
205-numa node,nodeid=0 -numa node,nodeid=1 \
206-numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
207@end example
208
209@samp{mem} assigns a given RAM amount to a node. @samp{memdev}
210assigns RAM from a given memory backend device to a node. If
211@samp{mem} and @samp{memdev} are omitted in all nodes, RAM is
212split equally between them.
213
214@samp{mem} and @samp{memdev} are mutually exclusive. Furthermore,
215if one node uses @samp{memdev}, all of them have to use it.
216
217@var{source} and @var{destination} are NUMA node IDs.
218@var{distance} is the NUMA distance from @var{source} to @var{destination}.
219The distance from a node to itself is always 10. If any pair of nodes is
220given a distance, then all pairs must be given distances. Although, when
221distances are only given in one direction for each pair of nodes, then
222the distances in the opposite directions are assumed to be the same. If,
223however, an asymmetrical pair of distances is given for even one node
224pair, then all node pairs must be provided distance values for both
225directions, even when they are symmetrical. When a node is unreachable
226from another node, set the pair's distance to 255.
227
228Note that the -@option{numa} option doesn't allocate any of the
229specified resources, it just assigns existing resources to NUMA
230nodes. This means that one still has to use the @option{-m},
231@option{-smp} options to allocate RAM and VCPUs respectively.
232
233ETEXI
234
235DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd,
236    "-add-fd fd=fd,set=set[,opaque=opaque]\n"
237    "                Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL)
238STEXI
239@item -add-fd fd=@var{fd},set=@var{set}[,opaque=@var{opaque}]
240@findex -add-fd
241
242Add a file descriptor to an fd set.  Valid options are:
243
244@table @option
245@item fd=@var{fd}
246This option defines the file descriptor of which a duplicate is added to fd set.
247The file descriptor cannot be stdin, stdout, or stderr.
248@item set=@var{set}
249This option defines the ID of the fd set to add the file descriptor to.
250@item opaque=@var{opaque}
251This option defines a free-form string that can be used to describe @var{fd}.
252@end table
253
254You can open an image using pre-opened file descriptors from an fd set:
255@example
256qemu-system-i386
257-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
258-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
259-drive file=/dev/fdset/2,index=0,media=disk
260@end example
261ETEXI
262
263DEF("set", HAS_ARG, QEMU_OPTION_set,
264    "-set group.id.arg=value\n"
265    "                set <arg> parameter for item <id> of type <group>\n"
266    "                i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL)
267STEXI
268@item -set @var{group}.@var{id}.@var{arg}=@var{value}
269@findex -set
270Set parameter @var{arg} for item @var{id} of type @var{group}
271ETEXI
272
273DEF("global", HAS_ARG, QEMU_OPTION_global,
274    "-global driver.property=value\n"
275    "-global driver=driver,property=property,value=value\n"
276    "                set a global default for a driver property\n",
277    QEMU_ARCH_ALL)
278STEXI
279@item -global @var{driver}.@var{prop}=@var{value}
280@itemx -global driver=@var{driver},property=@var{property},value=@var{value}
281@findex -global
282Set default value of @var{driver}'s property @var{prop} to @var{value}, e.g.:
283
284@example
285qemu-system-i386 -global ide-hd.physical_block_size=4096 disk-image.img
286@end example
287
288In particular, you can use this to set driver properties for devices which are
289created automatically by the machine model. To create a device which is not
290created automatically and set properties on it, use -@option{device}.
291
292-global @var{driver}.@var{prop}=@var{value} is shorthand for -global
293driver=@var{driver},property=@var{prop},value=@var{value}.  The
294longhand syntax works even when @var{driver} contains a dot.
295ETEXI
296
297DEF("boot", HAS_ARG, QEMU_OPTION_boot,
298    "-boot [order=drives][,once=drives][,menu=on|off]\n"
299    "      [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
300    "                'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n"
301    "                'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n"
302    "                'sp_time': the period that splash picture last if menu=on, unit is ms\n"
303    "                'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n",
304    QEMU_ARCH_ALL)
305STEXI
306@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]
307@findex -boot
308Specify boot order @var{drives} as a string of drive letters. Valid
309drive letters depend on the target architecture. The x86 PC uses: a, b
310(floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
311from network adapter 1-4), hard disk boot is the default. To apply a
312particular boot order only on the first startup, specify it via
313@option{once}. Note that the @option{order} or @option{once} parameter
314should not be used together with the @option{bootindex} property of
315devices, since the firmware implementations normally do not support both
316at the same time.
317
318Interactive boot menus/prompts can be enabled via @option{menu=on} as far
319as firmware/BIOS supports them. The default is non-interactive boot.
320
321A splash picture could be passed to bios, enabling user to show it as logo,
322when option splash=@var{sp_name} is given and menu=on, If firmware/BIOS
323supports them. Currently Seabios for X86 system support it.
324limitation: The splash file could be a jpeg file or a BMP file in 24 BPP
325format(true color). The resolution should be supported by the SVGA mode, so
326the recommended is 320x240, 640x480, 800x640.
327
328A timeout could be passed to bios, guest will pause for @var{rb_timeout} ms
329when boot failed, then reboot. If @var{rb_timeout} is '-1', guest will not
330reboot, qemu passes '-1' to bios by default. Currently Seabios for X86
331system support it.
332
333Do strict boot via @option{strict=on} as far as firmware/BIOS
334supports it. This only effects when boot priority is changed by
335bootindex options. The default is non-strict boot.
336
337@example
338# try to boot from network first, then from hard disk
339qemu-system-i386 -boot order=nc
340# boot from CD-ROM first, switch back to default order after reboot
341qemu-system-i386 -boot once=d
342# boot with a splash picture for 5 seconds.
343qemu-system-i386 -boot menu=on,splash=/root/boot.bmp,splash-time=5000
344@end example
345
346Note: The legacy format '-boot @var{drives}' is still supported but its
347use is discouraged as it may be removed from future versions.
348ETEXI
349
350DEF("m", HAS_ARG, QEMU_OPTION_m,
351    "-m [size=]megs[,slots=n,maxmem=size]\n"
352    "                configure guest RAM\n"
353    "                size: initial amount of guest memory\n"
354    "                slots: number of hotplug slots (default: none)\n"
355    "                maxmem: maximum amount of guest memory (default: none)\n"
356    "NOTE: Some architectures might enforce a specific granularity\n",
357    QEMU_ARCH_ALL)
358STEXI
359@item -m [size=]@var{megs}[,slots=n,maxmem=size]
360@findex -m
361Sets guest startup RAM size to @var{megs} megabytes. Default is 128 MiB.
362Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in
363megabytes or gigabytes respectively. Optional pair @var{slots}, @var{maxmem}
364could be used to set amount of hotpluggable memory slots and maximum amount of
365memory. Note that @var{maxmem} must be aligned to the page size.
366
367For example, the following command-line sets the guest startup RAM size to
3681GB, creates 3 slots to hotplug additional memory and sets the maximum
369memory the guest can reach to 4GB:
370
371@example
372qemu-system-x86_64 -m 1G,slots=3,maxmem=4G
373@end example
374
375If @var{slots} and @var{maxmem} are not specified, memory hotplug won't
376be enabled and the guest startup RAM will never increase.
377ETEXI
378
379DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
380    "-mem-path FILE  provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
381STEXI
382@item -mem-path @var{path}
383@findex -mem-path
384Allocate guest RAM from a temporarily created file in @var{path}.
385ETEXI
386
387DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc,
388    "-mem-prealloc   preallocate guest memory (use with -mem-path)\n",
389    QEMU_ARCH_ALL)
390STEXI
391@item -mem-prealloc
392@findex -mem-prealloc
393Preallocate memory when using -mem-path.
394ETEXI
395
396DEF("k", HAS_ARG, QEMU_OPTION_k,
397    "-k language     use keyboard layout (for example 'fr' for French)\n",
398    QEMU_ARCH_ALL)
399STEXI
400@item -k @var{language}
401@findex -k
402Use keyboard layout @var{language} (for example @code{fr} for
403French). This option is only needed where it is not easy to get raw PC
404keycodes (e.g. on Macs, with some X11 servers or with a VNC or curses
405display). You don't normally need to use it on PC/Linux or PC/Windows
406hosts.
407
408The available layouts are:
409@example
410ar  de-ch  es  fo     fr-ca  hu  ja  mk     no  pt-br  sv
411da  en-gb  et  fr     fr-ch  is  lt  nl     pl  ru     th
412de  en-us  fi  fr-be  hr     it  lv  nl-be  pt  sl     tr
413@end example
414
415The default is @code{en-us}.
416ETEXI
417
418
419DEF("audio-help", 0, QEMU_OPTION_audio_help,
420    "-audio-help     print list of audio drivers and their options\n",
421    QEMU_ARCH_ALL)
422STEXI
423@item -audio-help
424@findex -audio-help
425Will show the audio subsystem help: list of drivers, tunable
426parameters.
427ETEXI
428
429DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw,
430    "-soundhw c1,... enable audio support\n"
431    "                and only specified sound cards (comma separated list)\n"
432    "                use '-soundhw help' to get the list of supported cards\n"
433    "                use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL)
434STEXI
435@item -soundhw @var{card1}[,@var{card2},...] or -soundhw all
436@findex -soundhw
437Enable audio and selected sound hardware. Use 'help' to print all
438available sound hardware.
439
440@example
441qemu-system-i386 -soundhw sb16,adlib disk.img
442qemu-system-i386 -soundhw es1370 disk.img
443qemu-system-i386 -soundhw ac97 disk.img
444qemu-system-i386 -soundhw hda disk.img
445qemu-system-i386 -soundhw all disk.img
446qemu-system-i386 -soundhw help
447@end example
448
449Note that Linux's i810_audio OSS kernel (for AC97) module might
450require manually specifying clocking.
451
452@example
453modprobe i810_audio clocking=48000
454@end example
455ETEXI
456
457DEF("device", HAS_ARG, QEMU_OPTION_device,
458    "-device driver[,prop[=value][,...]]\n"
459    "                add device (based on driver)\n"
460    "                prop=value,... sets driver properties\n"
461    "                use '-device help' to print all possible drivers\n"
462    "                use '-device driver,help' to print all possible properties\n",
463    QEMU_ARCH_ALL)
464STEXI
465@item -device @var{driver}[,@var{prop}[=@var{value}][,...]]
466@findex -device
467Add device @var{driver}.  @var{prop}=@var{value} sets driver
468properties.  Valid properties depend on the driver.  To get help on
469possible drivers and properties, use @code{-device help} and
470@code{-device @var{driver},help}.
471
472Some drivers are:
473@item -device ipmi-bmc-sim,id=@var{id}[,slave_addr=@var{val}][,sdrfile=@var{file}][,furareasize=@var{val}][,furdatafile=@var{file}]
474
475Add an IPMI BMC.  This is a simulation of a hardware management
476interface processor that normally sits on a system.  It provides
477a watchdog and the ability to reset and power control the system.
478You need to connect this to an IPMI interface to make it useful
479
480The IPMI slave address to use for the BMC.  The default is 0x20.
481This address is the BMC's address on the I2C network of management
482controllers.  If you don't know what this means, it is safe to ignore
483it.
484
485@table @option
486@item bmc=@var{id}
487The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
488@item slave_addr=@var{val}
489Define slave address to use for the BMC.  The default is 0x20.
490@item sdrfile=@var{file}
491file containing raw Sensor Data Records (SDR) data. The default is none.
492@item fruareasize=@var{val}
493size of a Field Replaceable Unit (FRU) area.  The default is 1024.
494@item frudatafile=@var{file}
495file containing raw Field Replaceable Unit (FRU) inventory data. The default is none.
496@end table
497
498@item -device ipmi-bmc-extern,id=@var{id},chardev=@var{id}[,slave_addr=@var{val}]
499
500Add a connection to an external IPMI BMC simulator.  Instead of
501locally emulating the BMC like the above item, instead connect
502to an external entity that provides the IPMI services.
503
504A connection is made to an external BMC simulator.  If you do this, it
505is strongly recommended that you use the "reconnect=" chardev option
506to reconnect to the simulator if the connection is lost.  Note that if
507this is not used carefully, it can be a security issue, as the
508interface has the ability to send resets, NMIs, and power off the VM.
509It's best if QEMU makes a connection to an external simulator running
510on a secure port on localhost, so neither the simulator nor QEMU is
511exposed to any outside network.
512
513See the "lanserv/README.vm" file in the OpenIPMI library for more
514details on the external interface.
515
516@item -device isa-ipmi-kcs,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
517
518Add a KCS IPMI interafce on the ISA bus.  This also adds a
519corresponding ACPI and SMBIOS entries, if appropriate.
520
521@table @option
522@item bmc=@var{id}
523The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above.
524@item ioport=@var{val}
525Define the I/O address of the interface.  The default is 0xca0 for KCS.
526@item irq=@var{val}
527Define the interrupt to use.  The default is 5.  To disable interrupts,
528set this to 0.
529@end table
530
531@item -device isa-ipmi-bt,bmc=@var{id}[,ioport=@var{val}][,irq=@var{val}]
532
533Like the KCS interface, but defines a BT interface.  The default port is
5340xe4 and the default interrupt is 5.
535
536ETEXI
537
538DEF("name", HAS_ARG, QEMU_OPTION_name,
539    "-name string1[,process=string2][,debug-threads=on|off]\n"
540    "                set the name of the guest\n"
541    "                string1 sets the window title and string2 the process name (on Linux)\n"
542    "                When debug-threads is enabled, individual threads are given a separate name (on Linux)\n"
543    "                NOTE: The thread names are for debugging and not a stable API.\n",
544    QEMU_ARCH_ALL)
545STEXI
546@item -name @var{name}
547@findex -name
548Sets the @var{name} of the guest.
549This name will be displayed in the SDL window caption.
550The @var{name} will also be used for the VNC server.
551Also optionally set the top visible process name in Linux.
552Naming of individual threads can also be enabled on Linux to aid debugging.
553ETEXI
554
555DEF("uuid", HAS_ARG, QEMU_OPTION_uuid,
556    "-uuid %08x-%04x-%04x-%04x-%012x\n"
557    "                specify machine UUID\n", QEMU_ARCH_ALL)
558STEXI
559@item -uuid @var{uuid}
560@findex -uuid
561Set system UUID.
562ETEXI
563
564STEXI
565@end table
566ETEXI
567DEFHEADING()
568
569DEFHEADING(Block device options:)
570STEXI
571@table @option
572ETEXI
573
574DEF("fda", HAS_ARG, QEMU_OPTION_fda,
575    "-fda/-fdb file  use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL)
576DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL)
577STEXI
578@item -fda @var{file}
579@itemx -fdb @var{file}
580@findex -fda
581@findex -fdb
582Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
583ETEXI
584
585DEF("hda", HAS_ARG, QEMU_OPTION_hda,
586    "-hda/-hdb file  use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL)
587DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL)
588DEF("hdc", HAS_ARG, QEMU_OPTION_hdc,
589    "-hdc/-hdd file  use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL)
590DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL)
591STEXI
592@item -hda @var{file}
593@itemx -hdb @var{file}
594@itemx -hdc @var{file}
595@itemx -hdd @var{file}
596@findex -hda
597@findex -hdb
598@findex -hdc
599@findex -hdd
600Use @var{file} as hard disk 0, 1, 2 or 3 image (@pxref{disk_images}).
601ETEXI
602
603DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom,
604    "-cdrom file     use 'file' as IDE cdrom image (cdrom is ide1 master)\n",
605    QEMU_ARCH_ALL)
606STEXI
607@item -cdrom @var{file}
608@findex -cdrom
609Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
610@option{-cdrom} at the same time). You can use the host CD-ROM by
611using @file{/dev/cdrom} as filename (@pxref{host_drives}).
612ETEXI
613
614DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
615    "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
616    "          [,cache.direct=on|off][,cache.no-flush=on|off]\n"
617    "          [,read-only=on|off][,detect-zeroes=on|off|unmap]\n"
618    "          [,driver specific parameters...]\n"
619    "                configure a block backend\n", QEMU_ARCH_ALL)
620STEXI
621@item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
622@findex -blockdev
623
624Define a new block driver node. Some of the options apply to all block drivers,
625other options are only accepted for a specific block driver. See below for a
626list of generic options and options for the most common block drivers.
627
628Options that expect a reference to another node (e.g. @code{file}) can be
629given in two ways. Either you specify the node name of an already existing node
630(file=@var{node-name}), or you define a new node inline, adding options
631for the referenced node after a dot (file.filename=@var{path},file.aio=native).
632
633A block driver node created with @option{-blockdev} can be used for a guest
634device by specifying its node name for the @code{drive} property in a
635@option{-device} argument that defines a block device.
636
637@table @option
638@item Valid options for any block driver node:
639
640@table @code
641@item driver
642Specifies the block driver to use for the given node.
643@item node-name
644This defines the name of the block driver node by which it will be referenced
645later. The name must be unique, i.e. it must not match the name of a different
646block driver node, or (if you use @option{-drive} as well) the ID of a drive.
647
648If no node name is specified, it is automatically generated. The generated node
649name is not intended to be predictable and changes between QEMU invocations.
650For the top level, an explicit node name must be specified.
651@item read-only
652Open the node read-only. Guest write attempts will fail.
653@item cache.direct
654The host page cache can be avoided with @option{cache.direct=on}. This will
655attempt to do disk IO directly to the guest's memory. QEMU may still perform an
656internal copy of the data.
657@item cache.no-flush
658In case you don't care about data integrity over host failures, you can use
659@option{cache.no-flush=on}. This option tells QEMU that it never needs to write
660any data to the disk but can instead keep things in cache. If anything goes
661wrong, like your host losing power, the disk storage getting disconnected
662accidentally, etc. your image will most probably be rendered unusable.
663@item discard=@var{discard}
664@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls
665whether @code{discard} (also known as @code{trim} or @code{unmap}) requests are
666ignored or passed to the filesystem. Some machine types may not support
667discard requests.
668@item detect-zeroes=@var{detect-zeroes}
669@var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic
670conversion of plain zero writes by the OS to driver specific optimized
671zero write commands. You may even choose "unmap" if @var{discard} is set
672to "unmap" to allow a zero write to be converted to an @code{unmap} operation.
673@end table
674
675@item Driver-specific options for @code{file}
676
677This is the protocol-level block driver for accessing regular files.
678
679@table @code
680@item filename
681The path to the image file in the local filesystem
682@item aio
683Specifies the AIO backend (threads/native, default: threads)
684@item locking
685Specifies whether the image file is protected with Linux OFD / POSIX locks. The
686default is to use the Linux Open File Descriptor API if available, otherwise no
687lock is applied.  (auto/on/off, default: auto)
688@end table
689Example:
690@example
691-blockdev driver=file,node-name=disk,filename=disk.img
692@end example
693
694@item Driver-specific options for @code{raw}
695
696This is the image format block driver for raw images. It is usually
697stacked on top of a protocol level block driver such as @code{file}.
698
699@table @code
700@item file
701Reference to or definition of the data source block driver node
702(e.g. a @code{file} driver node)
703@end table
704Example 1:
705@example
706-blockdev driver=file,node-name=disk_file,filename=disk.img
707-blockdev driver=raw,node-name=disk,file=disk_file
708@end example
709Example 2:
710@example
711-blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img
712@end example
713
714@item Driver-specific options for @code{qcow2}
715
716This is the image format block driver for qcow2 images. It is usually
717stacked on top of a protocol level block driver such as @code{file}.
718
719@table @code
720@item file
721Reference to or definition of the data source block driver node
722(e.g. a @code{file} driver node)
723
724@item backing
725Reference to or definition of the backing file block device (default is taken
726from the image file). It is allowed to pass @code{null} here in order to disable
727the default backing file.
728
729@item lazy-refcounts
730Whether to enable the lazy refcounts feature (on/off; default is taken from the
731image file)
732
733@item cache-size
734The maximum total size of the L2 table and refcount block caches in bytes
735(default: the sum of l2-cache-size and refcount-cache-size)
736
737@item l2-cache-size
738The maximum size of the L2 table cache in bytes
739(default: if cache-size is not specified - 32M on Linux platforms, and 8M on
740non-Linux platforms; otherwise, as large as possible within the cache-size,
741while permitting the requested or the minimal refcount cache size)
742
743@item refcount-cache-size
744The maximum size of the refcount block cache in bytes
745(default: 4 times the cluster size; or if cache-size is specified, the part of
746it which is not used for the L2 cache)
747
748@item cache-clean-interval
749Clean unused entries in the L2 and refcount caches. The interval is in seconds.
750The default value is 600 on supporting platforms, and 0 on other platforms.
751Setting it to 0 disables this feature.
752
753@item pass-discard-request
754Whether discard requests to the qcow2 device should be forwarded to the data
755source (on/off; default: on if discard=unmap is specified, off otherwise)
756
757@item pass-discard-snapshot
758Whether discard requests for the data source should be issued when a snapshot
759operation (e.g. deleting a snapshot) frees clusters in the qcow2 file (on/off;
760default: on)
761
762@item pass-discard-other
763Whether discard requests for the data source should be issued on other
764occasions where a cluster gets freed (on/off; default: off)
765
766@item overlap-check
767Which overlap checks to perform for writes to the image
768(none/constant/cached/all; default: cached). For details or finer
769granularity control refer to the QAPI documentation of @code{blockdev-add}.
770@end table
771
772Example 1:
773@example
774-blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2
775-blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216
776@end example
777Example 2:
778@example
779-blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2
780@end example
781
782@item Driver-specific options for other drivers
783Please refer to the QAPI documentation of the @code{blockdev-add} QMP command.
784
785@end table
786
787ETEXI
788
789DEF("drive", HAS_ARG, QEMU_OPTION_drive,
790    "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
791    "       [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
792    "       [,snapshot=on|off][,rerror=ignore|stop|report]\n"
793    "       [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n"
794    "       [,readonly=on|off][,copy-on-read=on|off]\n"
795    "       [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
796    "       [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
797    "       [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
798    "       [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
799    "       [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
800    "       [[,iops_size=is]]\n"
801    "       [[,group=g]]\n"
802    "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
803STEXI
804@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
805@findex -drive
806
807Define a new drive. This includes creating a block driver node (the backend) as
808well as a guest device, and is mostly a shortcut for defining the corresponding
809@option{-blockdev} and @option{-device} options.
810
811@option{-drive} accepts all options that are accepted by @option{-blockdev}. In
812addition, it knows the following options:
813
814@table @option
815@item file=@var{file}
816This option defines which disk image (@pxref{disk_images}) to use with
817this drive. If the filename contains comma, you must double it
818(for instance, "file=my,,file" to use file "my,file").
819
820Special files such as iSCSI devices can be specified using protocol
821specific URLs. See the section for "Device URL Syntax" for more information.
822@item if=@var{interface}
823This option defines on which type on interface the drive is connected.
824Available types are: ide, scsi, sd, mtd, floppy, pflash, virtio, none.
825@item bus=@var{bus},unit=@var{unit}
826These options define where is connected the drive by defining the bus number and
827the unit id.
828@item index=@var{index}
829This option defines where is connected the drive by using an index in the list
830of available connectors of a given interface type.
831@item media=@var{media}
832This option defines the type of the media: disk or cdrom.
833@item snapshot=@var{snapshot}
834@var{snapshot} is "on" or "off" and controls snapshot mode for the given drive
835(see @option{-snapshot}).
836@item cache=@var{cache}
837@var{cache} is "none", "writeback", "unsafe", "directsync" or "writethrough"
838and controls how the host cache is used to access block data. This is a
839shortcut that sets the @option{cache.direct} and @option{cache.no-flush}
840options (as in @option{-blockdev}), and additionally @option{cache.writeback},
841which provides a default for the @option{write-cache} option of block guest
842devices (as in @option{-device}). The modes correspond to the following
843settings:
844
845@c Our texi2pod.pl script doesn't support @multitable, so fall back to using
846@c plain ASCII art (well, UTF-8 art really). This looks okay both in the manpage
847@c and the HTML output.
848@example
849@             │ cache.writeback   cache.direct   cache.no-flush
850─────────────┼─────────────────────────────────────────────────
851writeback    │ on                off            off
852none         │ on                on             off
853writethrough │ off               off            off
854directsync   │ off               on             off
855unsafe       │ on                off            on
856@end example
857
858The default mode is @option{cache=writeback}.
859
860@item aio=@var{aio}
861@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
862@item format=@var{format}
863Specify which disk @var{format} will be used rather than detecting
864the format.  Can be used to specify format=raw to avoid interpreting
865an untrusted format header.
866@item werror=@var{action},rerror=@var{action}
867Specify which @var{action} to take on write and read errors. Valid actions are:
868"ignore" (ignore the error and try to continue), "stop" (pause QEMU),
869"report" (report the error to the guest), "enospc" (pause QEMU only if the
870host disk is full; report the error to the guest otherwise).
871The default setting is @option{werror=enospc} and @option{rerror=report}.
872@item copy-on-read=@var{copy-on-read}
873@var{copy-on-read} is "on" or "off" and enables whether to copy read backing
874file sectors into the image file.
875@item bps=@var{b},bps_rd=@var{r},bps_wr=@var{w}
876Specify bandwidth throttling limits in bytes per second, either for all request
877types or for reads or writes only.  Small values can lead to timeouts or hangs
878inside the guest.  A safe minimum for disks is 2 MB/s.
879@item bps_max=@var{bm},bps_rd_max=@var{rm},bps_wr_max=@var{wm}
880Specify bursts in bytes per second, either for all request types or for reads
881or writes only.  Bursts allow the guest I/O to spike above the limit
882temporarily.
883@item iops=@var{i},iops_rd=@var{r},iops_wr=@var{w}
884Specify request rate limits in requests per second, either for all request
885types or for reads or writes only.
886@item iops_max=@var{bm},iops_rd_max=@var{rm},iops_wr_max=@var{wm}
887Specify bursts in requests per second, either for all request types or for reads
888or writes only.  Bursts allow the guest I/O to spike above the limit
889temporarily.
890@item iops_size=@var{is}
891Let every @var{is} bytes of a request count as a new request for iops
892throttling purposes.  Use this option to prevent guests from circumventing iops
893limits by sending fewer but larger requests.
894@item group=@var{g}
895Join a throttling quota group with given name @var{g}.  All drives that are
896members of the same group are accounted for together.  Use this option to
897prevent guests from circumventing throttling limits by using many small disks
898instead of a single larger disk.
899@end table
900
901By default, the @option{cache.writeback=on} mode is used. It will report data
902writes as completed as soon as the data is present in the host page cache.
903This is safe as long as your guest OS makes sure to correctly flush disk caches
904where needed. If your guest OS does not handle volatile disk write caches
905correctly and your host crashes or loses power, then the guest may experience
906data corruption.
907
908For such guests, you should consider using @option{cache.writeback=off}. This
909means that the host page cache will be used to read and write data, but write
910notification will be sent to the guest only after QEMU has made sure to flush
911each write to the disk. Be aware that this has a major impact on performance.
912
913When using the @option{-snapshot} option, unsafe caching is always used.
914
915Copy-on-read avoids accessing the same backing file sectors repeatedly and is
916useful when the backing file is over a slow network.  By default copy-on-read
917is off.
918
919Instead of @option{-cdrom} you can use:
920@example
921qemu-system-i386 -drive file=file,index=2,media=cdrom
922@end example
923
924Instead of @option{-hda}, @option{-hdb}, @option{-hdc}, @option{-hdd}, you can
925use:
926@example
927qemu-system-i386 -drive file=file,index=0,media=disk
928qemu-system-i386 -drive file=file,index=1,media=disk
929qemu-system-i386 -drive file=file,index=2,media=disk
930qemu-system-i386 -drive file=file,index=3,media=disk
931@end example
932
933You can open an image using pre-opened file descriptors from an fd set:
934@example
935qemu-system-i386
936-add-fd fd=3,set=2,opaque="rdwr:/path/to/file"
937-add-fd fd=4,set=2,opaque="rdonly:/path/to/file"
938-drive file=/dev/fdset/2,index=0,media=disk
939@end example
940
941You can connect a CDROM to the slave of ide0:
942@example
943qemu-system-i386 -drive file=file,if=ide,index=1,media=cdrom
944@end example
945
946If you don't specify the "file=" argument, you define an empty drive:
947@example
948qemu-system-i386 -drive if=ide,index=1,media=cdrom
949@end example
950
951Instead of @option{-fda}, @option{-fdb}, you can use:
952@example
953qemu-system-i386 -drive file=file,index=0,if=floppy
954qemu-system-i386 -drive file=file,index=1,if=floppy
955@end example
956
957By default, @var{interface} is "ide" and @var{index} is automatically
958incremented:
959@example
960qemu-system-i386 -drive file=a -drive file=b"
961@end example
962is interpreted like:
963@example
964qemu-system-i386 -hda a -hdb b
965@end example
966ETEXI
967
968DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock,
969    "-mtdblock file  use 'file' as on-board Flash memory image\n",
970    QEMU_ARCH_ALL)
971STEXI
972@item -mtdblock @var{file}
973@findex -mtdblock
974Use @var{file} as on-board Flash memory image.
975ETEXI
976
977DEF("sd", HAS_ARG, QEMU_OPTION_sd,
978    "-sd file        use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL)
979STEXI
980@item -sd @var{file}
981@findex -sd
982Use @var{file} as SecureDigital card image.
983ETEXI
984
985DEF("pflash", HAS_ARG, QEMU_OPTION_pflash,
986    "-pflash file    use 'file' as a parallel flash image\n", QEMU_ARCH_ALL)
987STEXI
988@item -pflash @var{file}
989@findex -pflash
990Use @var{file} as a parallel flash image.
991ETEXI
992
993DEF("snapshot", 0, QEMU_OPTION_snapshot,
994    "-snapshot       write to temporary files instead of disk image files\n",
995    QEMU_ARCH_ALL)
996STEXI
997@item -snapshot
998@findex -snapshot
999Write to temporary files instead of disk image files. In this case,
1000the raw disk image you use is not written back. You can however force
1001the write back by pressing @key{C-a s} (@pxref{disk_images}).
1002ETEXI
1003
1004DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
1005    "-fsdev fsdriver,id=id[,path=path,][security_model={mapped-xattr|mapped-file|passthrough|none}]\n"
1006    " [,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd][,fmode=fmode][,dmode=dmode]\n"
1007    " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n"
1008    " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n"
1009    " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n"
1010    " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n"
1011    " [[,throttling.iops-size=is]]\n",
1012    QEMU_ARCH_ALL)
1013
1014STEXI
1015
1016@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}][,fmode=@var{fmode}][,dmode=@var{dmode}]
1017@findex -fsdev
1018Define a new file system device. Valid options are:
1019@table @option
1020@item @var{fsdriver}
1021This option specifies the fs driver backend to use.
1022Currently "local", "handle" and "proxy" file system drivers are supported.
1023@item id=@var{id}
1024Specifies identifier for this device
1025@item path=@var{path}
1026Specifies the export path for the file system device. Files under
1027this path will be available to the 9p client on the guest.
1028@item security_model=@var{security_model}
1029Specifies the security model to be used for this export path.
1030Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1031In "passthrough" security model, files are stored using the same
1032credentials as they are created on the guest. This requires QEMU
1033to run as root. In "mapped-xattr" security model, some of the file
1034attributes like uid, gid, mode bits and link target are stored as
1035file attributes. For "mapped-file" these attributes are stored in the
1036hidden .virtfs_metadata directory. Directories exported by this security model cannot
1037interact with other unix tools. "none" security model is same as
1038passthrough except the sever won't report failures if it fails to
1039set file attributes like ownership. Security model is mandatory
1040only for local fsdriver. Other fsdrivers (like handle, proxy) don't take
1041security model as a parameter.
1042@item writeout=@var{writeout}
1043This is an optional argument. The only supported value is "immediate".
1044This means that host page cache will be used to read and write data but
1045write notification will be sent to the guest only when the data has been
1046reported as written by the storage subsystem.
1047@item readonly
1048Enables exporting 9p share as a readonly mount for guests. By default
1049read-write access is given.
1050@item socket=@var{socket}
1051Enables proxy filesystem driver to use passed socket file for communicating
1052with virtfs-proxy-helper
1053@item sock_fd=@var{sock_fd}
1054Enables proxy filesystem driver to use passed socket descriptor for
1055communicating with virtfs-proxy-helper. Usually a helper like libvirt
1056will create socketpair and pass one of the fds as sock_fd
1057@item fmode=@var{fmode}
1058Specifies the default mode for newly created files on the host. Works only
1059with security models "mapped-xattr" and "mapped-file".
1060@item dmode=@var{dmode}
1061Specifies the default mode for newly created directories on the host. Works
1062only with security models "mapped-xattr" and "mapped-file".
1063@end table
1064
1065-fsdev option is used along with -device driver "virtio-9p-pci".
1066@item -device virtio-9p-pci,fsdev=@var{id},mount_tag=@var{mount_tag}
1067Options for virtio-9p-pci driver are:
1068@table @option
1069@item fsdev=@var{id}
1070Specifies the id value specified along with -fsdev option
1071@item mount_tag=@var{mount_tag}
1072Specifies the tag name to be used by the guest to mount this export point
1073@end table
1074
1075ETEXI
1076
1077DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
1078    "-virtfs local,path=path,mount_tag=tag,security_model=[mapped-xattr|mapped-file|passthrough|none]\n"
1079    "        [,id=id][,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd][,fmode=fmode][,dmode=dmode]\n",
1080    QEMU_ARCH_ALL)
1081
1082STEXI
1083
1084@item -virtfs @var{fsdriver}[,path=@var{path}],mount_tag=@var{mount_tag}[,security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}][,fmode=@var{fmode}][,dmode=@var{dmode}]
1085@findex -virtfs
1086
1087The general form of a Virtual File system pass-through options are:
1088@table @option
1089@item @var{fsdriver}
1090This option specifies the fs driver backend to use.
1091Currently "local", "handle" and "proxy" file system drivers are supported.
1092@item id=@var{id}
1093Specifies identifier for this device
1094@item path=@var{path}
1095Specifies the export path for the file system device. Files under
1096this path will be available to the 9p client on the guest.
1097@item security_model=@var{security_model}
1098Specifies the security model to be used for this export path.
1099Supported security models are "passthrough", "mapped-xattr", "mapped-file" and "none".
1100In "passthrough" security model, files are stored using the same
1101credentials as they are created on the guest. This requires QEMU
1102to run as root. In "mapped-xattr" security model, some of the file
1103attributes like uid, gid, mode bits and link target are stored as
1104file attributes. For "mapped-file" these attributes are stored in the
1105hidden .virtfs_metadata directory. Directories exported by this security model cannot
1106interact with other unix tools. "none" security model is same as
1107passthrough except the sever won't report failures if it fails to
1108set file attributes like ownership. Security model is mandatory only
1109for local fsdriver. Other fsdrivers (like handle, proxy) don't take security
1110model as a parameter.
1111@item writeout=@var{writeout}
1112This is an optional argument. The only supported value is "immediate".
1113This means that host page cache will be used to read and write data but
1114write notification will be sent to the guest only when the data has been
1115reported as written by the storage subsystem.
1116@item readonly
1117Enables exporting 9p share as a readonly mount for guests. By default
1118read-write access is given.
1119@item socket=@var{socket}
1120Enables proxy filesystem driver to use passed socket file for
1121communicating with virtfs-proxy-helper. Usually a helper like libvirt
1122will create socketpair and pass one of the fds as sock_fd
1123@item sock_fd
1124Enables proxy filesystem driver to use passed 'sock_fd' as the socket
1125descriptor for interfacing with virtfs-proxy-helper
1126@item fmode=@var{fmode}
1127Specifies the default mode for newly created files on the host. Works only
1128with security models "mapped-xattr" and "mapped-file".
1129@item dmode=@var{dmode}
1130Specifies the default mode for newly created directories on the host. Works
1131only with security models "mapped-xattr" and "mapped-file".
1132@end table
1133ETEXI
1134
1135DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
1136    "-virtfs_synth Create synthetic file system image\n",
1137    QEMU_ARCH_ALL)
1138STEXI
1139@item -virtfs_synth
1140@findex -virtfs_synth
1141Create synthetic file system image
1142ETEXI
1143
1144DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
1145    "-iscsi [user=user][,password=password]\n"
1146    "       [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
1147    "       [,initiator-name=initiator-iqn][,id=target-iqn]\n"
1148    "       [,timeout=timeout]\n"
1149    "                iSCSI session parameters\n", QEMU_ARCH_ALL)
1150
1151STEXI
1152@item -iscsi
1153@findex -iscsi
1154Configure iSCSI session parameters.
1155ETEXI
1156
1157STEXI
1158@end table
1159ETEXI
1160DEFHEADING()
1161
1162DEFHEADING(USB options:)
1163STEXI
1164@table @option
1165ETEXI
1166
1167DEF("usb", 0, QEMU_OPTION_usb,
1168    "-usb            enable the USB driver (if it is not used by default yet)\n",
1169    QEMU_ARCH_ALL)
1170STEXI
1171@item -usb
1172@findex -usb
1173Enable the USB driver (if it is not used by default yet).
1174ETEXI
1175
1176DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
1177    "-usbdevice name add the host or guest USB device 'name'\n",
1178    QEMU_ARCH_ALL)
1179STEXI
1180
1181@item -usbdevice @var{devname}
1182@findex -usbdevice
1183Add the USB device @var{devname}. Note that this option is deprecated,
1184please use @code{-device usb-...} instead. @xref{usb_devices}.
1185
1186@table @option
1187
1188@item mouse
1189Virtual Mouse. This will override the PS/2 mouse emulation when activated.
1190
1191@item tablet
1192Pointer device that uses absolute coordinates (like a touchscreen). This
1193means QEMU is able to report the mouse position without having to grab the
1194mouse. Also overrides the PS/2 mouse emulation when activated.
1195
1196@item braille
1197Braille device.  This will use BrlAPI to display the braille output on a real
1198or fake device.
1199
1200@end table
1201ETEXI
1202
1203STEXI
1204@end table
1205ETEXI
1206DEFHEADING()
1207
1208DEFHEADING(Display options:)
1209STEXI
1210@table @option
1211ETEXI
1212
1213DEF("display", HAS_ARG, QEMU_OPTION_display,
1214    "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
1215    "            [,window_close=on|off][,gl=on|core|es|off]\n"
1216    "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
1217    "-display vnc=<display>[,<optargs>]\n"
1218    "-display curses\n"
1219    "-display none"
1220    "                select display type\n"
1221    "The default display is equivalent to\n"
1222#if defined(CONFIG_GTK)
1223            "\t\"-display gtk\"\n"
1224#elif defined(CONFIG_SDL)
1225            "\t\"-display sdl\"\n"
1226#elif defined(CONFIG_COCOA)
1227            "\t\"-display cocoa\"\n"
1228#elif defined(CONFIG_VNC)
1229            "\t\"-vnc localhost:0,to=99,id=default\"\n"
1230#else
1231            "\t\"-display none\"\n"
1232#endif
1233    , QEMU_ARCH_ALL)
1234STEXI
1235@item -display @var{type}
1236@findex -display
1237Select type of display to use. This option is a replacement for the
1238old style -sdl/-curses/... options. Valid values for @var{type} are
1239@table @option
1240@item sdl
1241Display video output via SDL (usually in a separate graphics
1242window; see the SDL documentation for other possibilities).
1243@item curses
1244Display video output via curses. For graphics device models which
1245support a text mode, QEMU can display this output using a
1246curses/ncurses interface. Nothing is displayed when the graphics
1247device is in graphical mode or if the graphics device does not support
1248a text mode. Generally only the VGA device models support text mode.
1249@item none
1250Do not display video output. The guest will still see an emulated
1251graphics card, but its output will not be displayed to the QEMU
1252user. This option differs from the -nographic option in that it
1253only affects what is done with video output; -nographic also changes
1254the destination of the serial and parallel port data.
1255@item gtk
1256Display video output in a GTK window. This interface provides drop-down
1257menus and other UI elements to configure and control the VM during
1258runtime.
1259@item vnc
1260Start a VNC server on display <arg>
1261@end table
1262ETEXI
1263
1264DEF("nographic", 0, QEMU_OPTION_nographic,
1265    "-nographic      disable graphical output and redirect serial I/Os to console\n",
1266    QEMU_ARCH_ALL)
1267STEXI
1268@item -nographic
1269@findex -nographic
1270Normally, if QEMU is compiled with graphical window support, it displays
1271output such as guest graphics, guest console, and the QEMU monitor in a
1272window. With this option, you can totally disable graphical output so
1273that QEMU is a simple command line application. The emulated serial port
1274is redirected on the console and muxed with the monitor (unless
1275redirected elsewhere explicitly). Therefore, you can still use QEMU to
1276debug a Linux kernel with a serial console. Use @key{C-a h} for help on
1277switching between the console and monitor.
1278ETEXI
1279
1280DEF("curses", 0, QEMU_OPTION_curses,
1281    "-curses         shorthand for -display curses\n",
1282    QEMU_ARCH_ALL)
1283STEXI
1284@item -curses
1285@findex -curses
1286Normally, if QEMU is compiled with graphical window support, it displays
1287output such as guest graphics, guest console, and the QEMU monitor in a
1288window. With this option, QEMU can display the VGA output when in text
1289mode using a curses/ncurses interface. Nothing is displayed in graphical
1290mode.
1291ETEXI
1292
1293DEF("no-frame", 0, QEMU_OPTION_no_frame,
1294    "-no-frame       open SDL window without a frame and window decorations\n",
1295    QEMU_ARCH_ALL)
1296STEXI
1297@item -no-frame
1298@findex -no-frame
1299Do not use decorations for SDL windows and start them using the whole
1300available screen space. This makes the using QEMU in a dedicated desktop
1301workspace more convenient.
1302ETEXI
1303
1304DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1305    "-alt-grab       use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1306    QEMU_ARCH_ALL)
1307STEXI
1308@item -alt-grab
1309@findex -alt-grab
1310Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
1311affects the special keys (for fullscreen, monitor-mode switching, etc).
1312ETEXI
1313
1314DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1315    "-ctrl-grab      use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1316    QEMU_ARCH_ALL)
1317STEXI
1318@item -ctrl-grab
1319@findex -ctrl-grab
1320Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
1321affects the special keys (for fullscreen, monitor-mode switching, etc).
1322ETEXI
1323
1324DEF("no-quit", 0, QEMU_OPTION_no_quit,
1325    "-no-quit        disable SDL window close capability\n", QEMU_ARCH_ALL)
1326STEXI
1327@item -no-quit
1328@findex -no-quit
1329Disable SDL window close capability.
1330ETEXI
1331
1332DEF("sdl", 0, QEMU_OPTION_sdl,
1333    "-sdl            shorthand for -display sdl\n", QEMU_ARCH_ALL)
1334STEXI
1335@item -sdl
1336@findex -sdl
1337Enable SDL.
1338ETEXI
1339
1340DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1341    "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1342    "       [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1343    "       [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1344    "       [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n"
1345    "       [,tls-ciphers=<list>]\n"
1346    "       [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1347    "       [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1348    "       [,sasl][,password=<secret>][,disable-ticketing]\n"
1349    "       [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1350    "       [,jpeg-wan-compression=[auto|never|always]]\n"
1351    "       [,zlib-glz-wan-compression=[auto|never|always]]\n"
1352    "       [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
1353    "       [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
1354    "       [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1355    "       [,gl=[on|off]][,rendernode=<file>]\n"
1356    "   enable spice\n"
1357    "   at least one of {port, tls-port} is mandatory\n",
1358    QEMU_ARCH_ALL)
1359STEXI
1360@item -spice @var{option}[,@var{option}[,...]]
1361@findex -spice
1362Enable the spice remote desktop protocol. Valid options are
1363
1364@table @option
1365
1366@item port=<nr>
1367Set the TCP port spice is listening on for plaintext channels.
1368
1369@item addr=<addr>
1370Set the IP address spice is listening on.  Default is any address.
1371
1372@item ipv4
1373@itemx ipv6
1374@itemx unix
1375Force using the specified IP version.
1376
1377@item password=<secret>
1378Set the password you need to authenticate.
1379
1380@item sasl
1381Require that the client use SASL to authenticate with the spice.
1382The exact choice of authentication method used is controlled from the
1383system / user's SASL configuration file for the 'qemu' service. This
1384is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1385unprivileged user, an environment variable SASL_CONF_PATH can be used
1386to make it search alternate locations for the service config.
1387While some SASL auth methods can also provide data encryption (eg GSSAPI),
1388it is recommended that SASL always be combined with the 'tls' and
1389'x509' settings to enable use of SSL and server certificates. This
1390ensures a data encryption preventing compromise of authentication
1391credentials.
1392
1393@item disable-ticketing
1394Allow client connects without authentication.
1395
1396@item disable-copy-paste
1397Disable copy paste between the client and the guest.
1398
1399@item disable-agent-file-xfer
1400Disable spice-vdagent based file-xfer between the client and the guest.
1401
1402@item tls-port=<nr>
1403Set the TCP port spice is listening on for encrypted channels.
1404
1405@item x509-dir=<dir>
1406Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1407
1408@item x509-key-file=<file>
1409@itemx x509-key-password=<file>
1410@itemx x509-cert-file=<file>
1411@itemx x509-cacert-file=<file>
1412@itemx x509-dh-key-file=<file>
1413The x509 file names can also be configured individually.
1414
1415@item tls-ciphers=<list>
1416Specify which ciphers to use.
1417
1418@item tls-channel=[main|display|cursor|inputs|record|playback]
1419@itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1420Force specific channel to be used with or without TLS encryption.  The
1421options can be specified multiple times to configure multiple
1422channels.  The special name "default" can be used to set the default
1423mode.  For channels which are not explicitly forced into one mode the
1424spice client is allowed to pick tls/plaintext as he pleases.
1425
1426@item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1427Configure image compression (lossless).
1428Default is auto_glz.
1429
1430@item jpeg-wan-compression=[auto|never|always]
1431@itemx zlib-glz-wan-compression=[auto|never|always]
1432Configure wan image compression (lossy for slow links).
1433Default is auto.
1434
1435@item streaming-video=[off|all|filter]
1436Configure video stream detection.  Default is off.
1437
1438@item agent-mouse=[on|off]
1439Enable/disable passing mouse events via vdagent.  Default is on.
1440
1441@item playback-compression=[on|off]
1442Enable/disable audio stream compression (using celt 0.5.1).  Default is on.
1443
1444@item seamless-migration=[on|off]
1445Enable/disable spice seamless migration. Default is off.
1446
1447@item gl=[on|off]
1448Enable/disable OpenGL context. Default is off.
1449
1450@item rendernode=<file>
1451DRM render node for OpenGL rendering. If not specified, it will pick
1452the first available. (Since 2.9)
1453
1454@end table
1455ETEXI
1456
1457DEF("portrait", 0, QEMU_OPTION_portrait,
1458    "-portrait       rotate graphical output 90 deg left (only PXA LCD)\n",
1459    QEMU_ARCH_ALL)
1460STEXI
1461@item -portrait
1462@findex -portrait
1463Rotate graphical output 90 deg left (only PXA LCD).
1464ETEXI
1465
1466DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1467    "-rotate <deg>   rotate graphical output some deg left (only PXA LCD)\n",
1468    QEMU_ARCH_ALL)
1469STEXI
1470@item -rotate @var{deg}
1471@findex -rotate
1472Rotate graphical output some deg left (only PXA LCD).
1473ETEXI
1474
1475DEF("vga", HAS_ARG, QEMU_OPTION_vga,
1476    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
1477    "                select video card type\n", QEMU_ARCH_ALL)
1478STEXI
1479@item -vga @var{type}
1480@findex -vga
1481Select type of VGA card to emulate. Valid values for @var{type} are
1482@table @option
1483@item cirrus
1484Cirrus Logic GD5446 Video card. All Windows versions starting from
1485Windows 95 should recognize and use this graphic card. For optimal
1486performances, use 16 bit color depth in the guest and the host OS.
1487(This card was the default before QEMU 2.2)
1488@item std
1489Standard VGA card with Bochs VBE extensions.  If your guest OS
1490supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1491to use high resolution modes (>= 1280x1024x16) then you should use
1492this option. (This card is the default since QEMU 2.2)
1493@item vmware
1494VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1495recent XFree86/XOrg server or Windows guest with a driver for this
1496card.
1497@item qxl
1498QXL paravirtual graphic card.  It is VGA compatible (including VESA
14992.0 VBE support).  Works best with qxl guest drivers installed though.
1500Recommended choice when using the spice protocol.
1501@item tcx
1502(sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1503sun4m machines and offers both 8-bit and 24-bit colour depths at a
1504fixed resolution of 1024x768.
1505@item cg3
1506(sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1507for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1508resolutions aimed at people wishing to run older Solaris versions.
1509@item virtio
1510Virtio VGA card.
1511@item none
1512Disable VGA card.
1513@end table
1514ETEXI
1515
1516DEF("full-screen", 0, QEMU_OPTION_full_screen,
1517    "-full-screen    start in full screen\n", QEMU_ARCH_ALL)
1518STEXI
1519@item -full-screen
1520@findex -full-screen
1521Start in full screen.
1522ETEXI
1523
1524DEF("g", 1, QEMU_OPTION_g ,
1525    "-g WxH[xDEPTH]  Set the initial graphical resolution and depth\n",
1526    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
1527STEXI
1528@item -g @var{width}x@var{height}[x@var{depth}]
1529@findex -g
1530Set the initial graphical resolution and depth (PPC, SPARC only).
1531ETEXI
1532
1533DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1534    "-vnc <display>  shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1535STEXI
1536@item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1537@findex -vnc
1538Normally, if QEMU is compiled with graphical window support, it displays
1539output such as guest graphics, guest console, and the QEMU monitor in a
1540window. With this option, you can have QEMU listen on VNC display
1541@var{display} and redirect the VGA display over the VNC session. It is
1542very useful to enable the usb tablet device when using this option
1543(option @option{-device usb-tablet}). When using the VNC display, you
1544must use the @option{-k} parameter to set the keyboard layout if you are
1545not using en-us. Valid syntax for the @var{display} is
1546
1547@table @option
1548
1549@item to=@var{L}
1550
1551With this option, QEMU will try next available VNC @var{display}s, until the
1552number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1553available, e.g. port 5900+@var{display} is already used by another
1554application. By default, to=0.
1555
1556@item @var{host}:@var{d}
1557
1558TCP connections will only be allowed from @var{host} on display @var{d}.
1559By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1560be omitted in which case the server will accept connections from any host.
1561
1562@item unix:@var{path}
1563
1564Connections will be allowed over UNIX domain sockets where @var{path} is the
1565location of a unix socket to listen for connections on.
1566
1567@item none
1568
1569VNC is initialized but not started. The monitor @code{change} command
1570can be used to later start the VNC server.
1571
1572@end table
1573
1574Following the @var{display} value there may be one or more @var{option} flags
1575separated by commas. Valid options are
1576
1577@table @option
1578
1579@item reverse
1580
1581Connect to a listening VNC client via a ``reverse'' connection. The
1582client is specified by the @var{display}. For reverse network
1583connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
1584is a TCP port number, not a display number.
1585
1586@item websocket
1587
1588Opens an additional TCP listening port dedicated to VNC Websocket connections.
1589If a bare @var{websocket} option is given, the Websocket port is
15905700+@var{display}. An alternative port can be specified with the
1591syntax @code{websocket}=@var{port}.
1592
1593If @var{host} is specified connections will only be allowed from this host.
1594It is possible to control the websocket listen address independently, using
1595the syntax @code{websocket}=@var{host}:@var{port}.
1596
1597If no TLS credentials are provided, the websocket connection runs in
1598unencrypted mode. If TLS credentials are provided, the websocket connection
1599requires encrypted client connections.
1600
1601@item password
1602
1603Require that password based authentication is used for client connections.
1604
1605The password must be set separately using the @code{set_password} command in
1606the @ref{pcsys_monitor}. The syntax to change your password is:
1607@code{set_password <protocol> <password>} where <protocol> could be either
1608"vnc" or "spice".
1609
1610If you would like to change <protocol> password expiration, you should use
1611@code{expire_password <protocol> <expiration-time>} where expiration time could
1612be one of the following options: now, never, +seconds or UNIX time of
1613expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
1614to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
1615date and time).
1616
1617You can also use keywords "now" or "never" for the expiration time to
1618allow <protocol> password to expire immediately or never expire.
1619
1620@item tls-creds=@var{ID}
1621
1622Provides the ID of a set of TLS credentials to use to secure the
1623VNC server. They will apply to both the normal VNC server socket
1624and the websocket socket (if enabled). Setting TLS credentials
1625will cause the VNC server socket to enable the VeNCrypt auth
1626mechanism.  The credentials should have been previously created
1627using the @option{-object tls-creds} argument.
1628
1629@item sasl
1630
1631Require that the client use SASL to authenticate with the VNC server.
1632The exact choice of authentication method used is controlled from the
1633system / user's SASL configuration file for the 'qemu' service. This
1634is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1635unprivileged user, an environment variable SASL_CONF_PATH can be used
1636to make it search alternate locations for the service config.
1637While some SASL auth methods can also provide data encryption (eg GSSAPI),
1638it is recommended that SASL always be combined with the 'tls' and
1639'x509' settings to enable use of SSL and server certificates. This
1640ensures a data encryption preventing compromise of authentication
1641credentials. See the @ref{vnc_security} section for details on using
1642SASL authentication.
1643
1644@item acl
1645
1646Turn on access control lists for checking of the x509 client certificate
1647and SASL party. For x509 certs, the ACL check is made against the
1648certificate's distinguished name. This is something that looks like
1649@code{C=GB,O=ACME,L=Boston,CN=bob}. For SASL party, the ACL check is
1650made against the username, which depending on the SASL plugin, may
1651include a realm component, eg @code{bob} or @code{bob@@EXAMPLE.COM}.
1652When the @option{acl} flag is set, the initial access list will be
1653empty, with a @code{deny} policy. Thus no one will be allowed to
1654use the VNC server until the ACLs have been loaded. This can be
1655achieved using the @code{acl} monitor command.
1656
1657@item lossy
1658
1659Enable lossy compression methods (gradient, JPEG, ...). If this
1660option is set, VNC client may receive lossy framebuffer updates
1661depending on its encoding settings. Enabling this option can save
1662a lot of bandwidth at the expense of quality.
1663
1664@item non-adaptive
1665
1666Disable adaptive encodings. Adaptive encodings are enabled by default.
1667An adaptive encoding will try to detect frequently updated screen regions,
1668and send updates in these regions using a lossy encoding (like JPEG).
1669This can be really helpful to save bandwidth when playing videos. Disabling
1670adaptive encodings restores the original static behavior of encodings
1671like Tight.
1672
1673@item share=[allow-exclusive|force-shared|ignore]
1674
1675Set display sharing policy.  'allow-exclusive' allows clients to ask
1676for exclusive access.  As suggested by the rfb spec this is
1677implemented by dropping other connections.  Connecting multiple
1678clients in parallel requires all clients asking for a shared session
1679(vncviewer: -shared switch).  This is the default.  'force-shared'
1680disables exclusive client access.  Useful for shared desktop sessions,
1681where you don't want someone forgetting specify -shared disconnect
1682everybody else.  'ignore' completely ignores the shared flag and
1683allows everybody connect unconditionally.  Doesn't conform to the rfb
1684spec but is traditional QEMU behavior.
1685
1686@item key-delay-ms
1687
1688Set keyboard delay, for key down and key up events, in milliseconds.
1689Default is 10.  Keyboards are low-bandwidth devices, so this slowdown
1690can help the device and guest to keep up and not lose events in case
1691events are arriving in bulk.  Possible causes for the latter are flaky
1692network connections, or scripts for automated testing.
1693
1694@end table
1695ETEXI
1696
1697STEXI
1698@end table
1699ETEXI
1700ARCHHEADING(, QEMU_ARCH_I386)
1701
1702ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
1703STEXI
1704@table @option
1705ETEXI
1706
1707DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
1708    "-win2k-hack     use it when installing Windows 2000 to avoid a disk full bug\n",
1709    QEMU_ARCH_I386)
1710STEXI
1711@item -win2k-hack
1712@findex -win2k-hack
1713Use it when installing Windows 2000 to avoid a disk full bug. After
1714Windows 2000 is installed, you no longer need this option (this option
1715slows down the IDE transfers).
1716ETEXI
1717
1718DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
1719    "-no-fd-bootchk  disable boot signature checking for floppy disks\n",
1720    QEMU_ARCH_I386)
1721STEXI
1722@item -no-fd-bootchk
1723@findex -no-fd-bootchk
1724Disable boot signature checking for floppy disks in BIOS. May
1725be needed to boot from old floppy disks.
1726ETEXI
1727
1728DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
1729           "-no-acpi        disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1730STEXI
1731@item -no-acpi
1732@findex -no-acpi
1733Disable ACPI (Advanced Configuration and Power Interface) support. Use
1734it if your guest OS complains about ACPI problems (PC target machine
1735only).
1736ETEXI
1737
1738DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
1739    "-no-hpet        disable HPET\n", QEMU_ARCH_I386)
1740STEXI
1741@item -no-hpet
1742@findex -no-hpet
1743Disable HPET support.
1744ETEXI
1745
1746DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
1747    "-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"
1748    "                ACPI table description\n", QEMU_ARCH_I386)
1749STEXI
1750@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}]...]
1751@findex -acpitable
1752Add ACPI table with specified header fields and context from specified files.
1753For file=, take whole ACPI table from the specified files, including all
1754ACPI headers (possible overridden by other options).
1755For data=, only data
1756portion of the table is used, all header information is specified in the
1757command line.
1758If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id
1759fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
1760to ensure the field matches required by the Microsoft SLIC spec and the ACPI
1761spec.
1762ETEXI
1763
1764DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
1765    "-smbios file=binary\n"
1766    "                load SMBIOS entry from binary file\n"
1767    "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
1768    "              [,uefi=on|off]\n"
1769    "                specify SMBIOS type 0 fields\n"
1770    "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
1771    "              [,uuid=uuid][,sku=str][,family=str]\n"
1772    "                specify SMBIOS type 1 fields\n"
1773    "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
1774    "              [,asset=str][,location=str]\n"
1775    "                specify SMBIOS type 2 fields\n"
1776    "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
1777    "              [,sku=str]\n"
1778    "                specify SMBIOS type 3 fields\n"
1779    "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
1780    "              [,asset=str][,part=str]\n"
1781    "                specify SMBIOS type 4 fields\n"
1782    "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
1783    "               [,asset=str][,part=str][,speed=%d]\n"
1784    "                specify SMBIOS type 17 fields\n",
1785    QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1786STEXI
1787@item -smbios file=@var{binary}
1788@findex -smbios
1789Load SMBIOS entry from binary file.
1790
1791@item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
1792Specify SMBIOS type 0 fields
1793
1794@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}]
1795Specify SMBIOS type 1 fields
1796
1797@item -smbios type=2[,manufacturer=@var{str}][,product=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,location=@var{str}][,family=@var{str}]
1798Specify SMBIOS type 2 fields
1799
1800@item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
1801Specify SMBIOS type 3 fields
1802
1803@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
1804Specify SMBIOS type 4 fields
1805
1806@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}]
1807Specify SMBIOS type 17 fields
1808ETEXI
1809
1810STEXI
1811@end table
1812ETEXI
1813DEFHEADING()
1814
1815DEFHEADING(Network options:)
1816STEXI
1817@table @option
1818ETEXI
1819
1820DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
1821#ifdef CONFIG_SLIRP
1822    "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n"
1823    "         [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
1824    "         [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
1825    "         [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
1826    "         [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
1827#ifndef _WIN32
1828                                             "[,smb=dir[,smbserver=addr]]\n"
1829#endif
1830    "                configure a user mode network backend with ID 'str',\n"
1831    "                its DHCP server and optional services\n"
1832#endif
1833#ifdef _WIN32
1834    "-netdev tap,id=str,ifname=name\n"
1835    "                configure a host TAP network backend with ID 'str'\n"
1836#else
1837    "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
1838    "         [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
1839    "         [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
1840    "         [,poll-us=n]\n"
1841    "                configure a host TAP network backend with ID 'str'\n"
1842    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1843    "                use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
1844    "                to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
1845    "                to deconfigure it\n"
1846    "                use '[down]script=no' to disable script execution\n"
1847    "                use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
1848    "                configure it\n"
1849    "                use 'fd=h' to connect to an already opened TAP interface\n"
1850    "                use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
1851    "                use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
1852    "                default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
1853    "                use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
1854    "                use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
1855    "                use vhost=on to enable experimental in kernel accelerator\n"
1856    "                    (only has effect for virtio guests which use MSIX)\n"
1857    "                use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
1858    "                use 'vhostfd=h' to connect to an already opened vhost net device\n"
1859    "                use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
1860    "                use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
1861    "                use 'poll-us=n' to speciy the maximum number of microseconds that could be\n"
1862    "                spent on busy polling for vhost net\n"
1863    "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
1864    "                configure a host TAP network backend with ID 'str' that is\n"
1865    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1866    "                using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
1867#endif
1868#ifdef __linux__
1869    "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
1870    "         [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n"
1871    "         [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n"
1872    "         [,rxcookie=rxcookie][,offset=offset]\n"
1873    "                configure a network backend with ID 'str' connected to\n"
1874    "                an Ethernet over L2TPv3 pseudowire.\n"
1875    "                Linux kernel 3.3+ as well as most routers can talk\n"
1876    "                L2TPv3. This transport allows connecting a VM to a VM,\n"
1877    "                VM to a router and even VM to Host. It is a nearly-universal\n"
1878    "                standard (RFC3391). Note - this implementation uses static\n"
1879    "                pre-configured tunnels (same as the Linux kernel).\n"
1880    "                use 'src=' to specify source address\n"
1881    "                use 'dst=' to specify destination address\n"
1882    "                use 'udp=on' to specify udp encapsulation\n"
1883    "                use 'srcport=' to specify source udp port\n"
1884    "                use 'dstport=' to specify destination udp port\n"
1885    "                use 'ipv6=on' to force v6\n"
1886    "                L2TPv3 uses cookies to prevent misconfiguration as\n"
1887    "                well as a weak security measure\n"
1888    "                use 'rxcookie=0x012345678' to specify a rxcookie\n"
1889    "                use 'txcookie=0x012345678' to specify a txcookie\n"
1890    "                use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
1891    "                use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
1892    "                use 'pincounter=on' to work around broken counter handling in peer\n"
1893    "                use 'offset=X' to add an extra offset between header and data\n"
1894#endif
1895    "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
1896    "                configure a network backend to connect to another network\n"
1897    "                using a socket connection\n"
1898    "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
1899    "                configure a network backend to connect to a multicast maddr and port\n"
1900    "                use 'localaddr=addr' to specify the host address to send packets from\n"
1901    "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
1902    "                configure a network backend to connect to another network\n"
1903    "                using an UDP tunnel\n"
1904#ifdef CONFIG_VDE
1905    "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
1906    "                configure a network backend to connect to port 'n' of a vde switch\n"
1907    "                running on host and listening for incoming connections on 'socketpath'.\n"
1908    "                Use group 'groupname' and mode 'octalmode' to change default\n"
1909    "                ownership and permissions for communication port.\n"
1910#endif
1911#ifdef CONFIG_NETMAP
1912    "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
1913    "                attach to the existing netmap-enabled network interface 'name', or to a\n"
1914    "                VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
1915    "                netmap device, defaults to '/dev/netmap')\n"
1916#endif
1917#ifdef CONFIG_POSIX
1918    "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
1919    "                configure a vhost-user network, backed by a chardev 'dev'\n"
1920#endif
1921    "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
1922    "                configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
1923DEF("nic", HAS_ARG, QEMU_OPTION_nic,
1924    "-nic [tap|bridge|"
1925#ifdef CONFIG_SLIRP
1926    "user|"
1927#endif
1928#ifdef __linux__
1929    "l2tpv3|"
1930#endif
1931#ifdef CONFIG_VDE
1932    "vde|"
1933#endif
1934#ifdef CONFIG_NETMAP
1935    "netmap|"
1936#endif
1937#ifdef CONFIG_POSIX
1938    "vhost-user|"
1939#endif
1940    "socket][,option][,...][mac=macaddr]\n"
1941    "                initialize an on-board / default host NIC (using MAC address\n"
1942    "                macaddr) and connect it to the given host network backend\n"
1943    "-nic none       use it alone to have zero network devices (the default is to\n"
1944    "                provided a 'user' network connection)\n",
1945    QEMU_ARCH_ALL)
1946DEF("net", HAS_ARG, QEMU_OPTION_net,
1947    "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
1948    "                configure or create an on-board (or machine default) NIC and\n"
1949    "                connect it to hub 0 (please use -nic unless you need a hub)\n"
1950    "-net ["
1951#ifdef CONFIG_SLIRP
1952    "user|"
1953#endif
1954    "tap|"
1955    "bridge|"
1956#ifdef CONFIG_VDE
1957    "vde|"
1958#endif
1959#ifdef CONFIG_NETMAP
1960    "netmap|"
1961#endif
1962    "socket][,option][,option][,...]\n"
1963    "                old way to initialize a host network interface\n"
1964    "                (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
1965STEXI
1966@item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
1967@findex -nic
1968This option is a shortcut for configuring both the on-board (default) guest
1969NIC hardware and the host network backend in one go. The host backend options
1970are the same as with the corresponding @option{-netdev} options below.
1971The guest NIC model can be set with @option{model=@var{modelname}}.
1972Use @option{model=help} to list the available device types.
1973The hardware MAC address can be set with @option{mac=@var{macaddr}}.
1974
1975The following two example do exactly the same, to show how @option{-nic} can
1976be used to shorten the command line length (note that the e1000 is the default
1977on i386, so the @option{model=e1000} parameter could even be omitted here, too):
1978@example
1979qemu-system-i386 -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
1980qemu-system-i386 -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
1981@end example
1982
1983@item -nic none
1984Indicate that no network devices should be configured. It is used to override
1985the default configuration (default NIC with ``user'' host network backend)
1986which is activated if no other networking options are provided.
1987
1988@item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
1989@findex -netdev
1990Configure user mode host network backend which requires no administrator
1991privilege to run. Valid options are:
1992
1993@table @option
1994@item id=@var{id}
1995Assign symbolic name for use in monitor commands.
1996
1997@item ipv4=on|off and ipv6=on|off
1998Specify that either IPv4 or IPv6 must be enabled. If neither is specified
1999both protocols are enabled.
2000
2001@item net=@var{addr}[/@var{mask}]
2002Set IP network address the guest will see. Optionally specify the netmask,
2003either in the form a.b.c.d or as number of valid top-most bits. Default is
200410.0.2.0/24.
2005
2006@item host=@var{addr}
2007Specify the guest-visible address of the host. Default is the 2nd IP in the
2008guest network, i.e. x.x.x.2.
2009
2010@item ipv6-net=@var{addr}[/@var{int}]
2011Set IPv6 network address the guest will see (default is fec0::/64). The
2012network prefix is given in the usual hexadecimal IPv6 address
2013notation. The prefix size is optional, and is given as the number of
2014valid top-most bits (default is 64).
2015
2016@item ipv6-host=@var{addr}
2017Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2018the guest network, i.e. xxxx::2.
2019
2020@item restrict=on|off
2021If this option is enabled, the guest will be isolated, i.e. it will not be
2022able to contact the host and no guest IP packets will be routed over the host
2023to the outside. This option does not affect any explicitly set forwarding rules.
2024
2025@item hostname=@var{name}
2026Specifies the client hostname reported by the built-in DHCP server.
2027
2028@item dhcpstart=@var{addr}
2029Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2030is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2031
2032@item dns=@var{addr}
2033Specify the guest-visible address of the virtual nameserver. The address must
2034be different from the host address. Default is the 3rd IP in the guest network,
2035i.e. x.x.x.3.
2036
2037@item ipv6-dns=@var{addr}
2038Specify the guest-visible address of the IPv6 virtual nameserver. The address
2039must be different from the host address. Default is the 3rd IP in the guest
2040network, i.e. xxxx::3.
2041
2042@item dnssearch=@var{domain}
2043Provides an entry for the domain-search list sent by the built-in
2044DHCP server. More than one domain suffix can be transmitted by specifying
2045this option multiple times. If supported, this will cause the guest to
2046automatically try to append the given domain suffix(es) in case a domain name
2047can not be resolved.
2048
2049Example:
2050@example
2051qemu-system-i386 -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2052@end example
2053
2054@item domainname=@var{domain}
2055Specifies the client domain name reported by the built-in DHCP server.
2056
2057@item tftp=@var{dir}
2058When using the user mode network stack, activate a built-in TFTP
2059server. The files in @var{dir} will be exposed as the root of a TFTP server.
2060The TFTP client on the guest must be configured in binary mode (use the command
2061@code{bin} of the Unix TFTP client).
2062
2063@item tftp-server-name=@var{name}
2064In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
206566). This can be used to advise the guest to load boot files or configurations
2066from a different server than the host address.
2067
2068@item bootfile=@var{file}
2069When using the user mode network stack, broadcast @var{file} as the BOOTP
2070filename. In conjunction with @option{tftp}, this can be used to network boot
2071a guest from a local directory.
2072
2073Example (using pxelinux):
2074@example
2075qemu-system-i386 -hda linux.img -boot n -device e1000,netdev=n1 \
2076    -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2077@end example
2078
2079@item smb=@var{dir}[,smbserver=@var{addr}]
2080When using the user mode network stack, activate a built-in SMB
2081server so that Windows OSes can access to the host files in @file{@var{dir}}
2082transparently. The IP address of the SMB server can be set to @var{addr}. By
2083default the 4th IP in the guest network is used, i.e. x.x.x.4.
2084
2085In the guest Windows OS, the line:
2086@example
208710.0.2.4 smbserver
2088@end example
2089must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2090or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2091
2092Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2093
2094Note that a SAMBA server must be installed on the host OS.
2095
2096@item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2097Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2098the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2099@var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2100given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2101be bound to a specific host interface. If no connection type is set, TCP is
2102used. This option can be given multiple times.
2103
2104For example, to redirect host X11 connection from screen 1 to guest
2105screen 0, use the following:
2106
2107@example
2108# on the host
2109qemu-system-i386 -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2110# this host xterm should open in the guest X11 server
2111xterm -display :1
2112@end example
2113
2114To redirect telnet connections from host port 5555 to telnet port on
2115the guest, use the following:
2116
2117@example
2118# on the host
2119qemu-system-i386 -nic user,hostfwd=tcp::5555-:23
2120telnet localhost 5555
2121@end example
2122
2123Then when you use on the host @code{telnet localhost 5555}, you
2124connect to the guest telnet server.
2125
2126@item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2127@itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2128Forward guest TCP connections to the IP address @var{server} on port @var{port}
2129to the character device @var{dev} or to a program executed by @var{cmd:command}
2130which gets spawned for each connection. This option can be given multiple times.
2131
2132You can either use a chardev directly and have that one used throughout QEMU's
2133lifetime, like in the following example:
2134
2135@example
2136# open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2137# the guest accesses it
2138qemu-system-i386 -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2139@end example
2140
2141Or you can execute a command on every TCP connection established by the guest,
2142so that QEMU behaves similar to an inetd process for that virtual server:
2143
2144@example
2145# call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2146# and connect the TCP stream to its stdin/stdout
2147qemu-system-i386 -nic  'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2148@end example
2149
2150@end table
2151
2152@item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
2153Configure a host TAP network backend with ID @var{id}.
2154
2155Use the network script @var{file} to configure it and the network script
2156@var{dfile} to deconfigure it. If @var{name} is not provided, the OS
2157automatically provides one. The default network configure script is
2158@file{/etc/qemu-ifup} and the default network deconfigure script is
2159@file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no}
2160to disable script execution.
2161
2162If running QEMU as an unprivileged user, use the network helper
2163@var{helper} to configure the TAP interface and attach it to the bridge.
2164The default network helper executable is @file{/path/to/qemu-bridge-helper}
2165and the default bridge device is @file{br0}.
2166
2167@option{fd}=@var{h} can be used to specify the handle of an already
2168opened host TAP interface.
2169
2170Examples:
2171
2172@example
2173#launch a QEMU instance with the default network script
2174qemu-system-i386 linux.img -nic tap
2175@end example
2176
2177@example
2178#launch a QEMU instance with two NICs, each one connected
2179#to a TAP device
2180qemu-system-i386 linux.img \
2181        -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \
2182        -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2183@end example
2184
2185@example
2186#launch a QEMU instance with the default network helper to
2187#connect a TAP device to bridge br0
2188qemu-system-i386 linux.img -device virtio-net-pci,netdev=n1 \
2189        -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2190@end example
2191
2192@item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}]
2193Connect a host TAP network interface to a host bridge device.
2194
2195Use the network helper @var{helper} to configure the TAP interface and
2196attach it to the bridge. The default network helper executable is
2197@file{/path/to/qemu-bridge-helper} and the default bridge
2198device is @file{br0}.
2199
2200Examples:
2201
2202@example
2203#launch a QEMU instance with the default network helper to
2204#connect a TAP device to bridge br0
2205qemu-system-i386 linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2206@end example
2207
2208@example
2209#launch a QEMU instance with the default network helper to
2210#connect a TAP device to bridge qemubr0
2211qemu-system-i386 linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2212@end example
2213
2214@item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2215
2216This host network backend can be used to connect the guest's network to
2217another QEMU virtual machine using a TCP socket connection. If @option{listen}
2218is specified, QEMU waits for incoming connections on @var{port}
2219(@var{host} is optional). @option{connect} is used to connect to
2220another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2221specifies an already opened TCP socket.
2222
2223Example:
2224@example
2225# launch a first QEMU instance
2226qemu-system-i386 linux.img \
2227                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2228                 -netdev socket,id=n1,listen=:1234
2229# connect the network of this instance to the network of the first instance
2230qemu-system-i386 linux.img \
2231                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2232                 -netdev socket,id=n2,connect=127.0.0.1:1234
2233@end example
2234
2235@item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2236
2237Configure a socket host network backend to share the guest's network traffic
2238with another QEMU virtual machines using a UDP multicast socket, effectively
2239making a bus for every QEMU with same multicast address @var{maddr} and @var{port}.
2240NOTES:
2241@enumerate
2242@item
2243Several QEMU can be running on different hosts and share same bus (assuming
2244correct multicast setup for these hosts).
2245@item
2246mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
2247@url{http://user-mode-linux.sf.net}.
2248@item
2249Use @option{fd=h} to specify an already opened UDP multicast socket.
2250@end enumerate
2251
2252Example:
2253@example
2254# launch one QEMU instance
2255qemu-system-i386 linux.img \
2256                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2257                 -netdev socket,id=n1,mcast=230.0.0.1:1234
2258# launch another QEMU instance on same "bus"
2259qemu-system-i386 linux.img \
2260                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2261                 -netdev socket,id=n2,mcast=230.0.0.1:1234
2262# launch yet another QEMU instance on same "bus"
2263qemu-system-i386 linux.img \
2264                 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \
2265                 -netdev socket,id=n3,mcast=230.0.0.1:1234
2266@end example
2267
2268Example (User Mode Linux compat.):
2269@example
2270# launch QEMU instance (note mcast address selected is UML's default)
2271qemu-system-i386 linux.img \
2272                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2273                 -netdev socket,id=n1,mcast=239.192.168.1:1102
2274# launch UML
2275/path/to/linux ubd0=/path/to/root_fs eth0=mcast
2276@end example
2277
2278Example (send packets from host's 1.2.3.4):
2279@example
2280qemu-system-i386 linux.img \
2281                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2282                 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2283@end example
2284
2285@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}]
2286Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3391) is a
2287popular protocol to transport Ethernet (and other Layer 2) data frames between
2288two systems. It is present in routers, firewalls and the Linux kernel
2289(from version 3.3 onwards).
2290
2291This transport allows a VM to communicate to another VM, router or firewall directly.
2292
2293@table @option
2294@item src=@var{srcaddr}
2295    source address (mandatory)
2296@item dst=@var{dstaddr}
2297    destination address (mandatory)
2298@item udp
2299    select udp encapsulation (default is ip).
2300@item srcport=@var{srcport}
2301    source udp port.
2302@item dstport=@var{dstport}
2303    destination udp port.
2304@item ipv6
2305    force v6, otherwise defaults to v4.
2306@item rxcookie=@var{rxcookie}
2307@itemx txcookie=@var{txcookie}
2308    Cookies are a weak form of security in the l2tpv3 specification.
2309Their function is mostly to prevent misconfiguration. By default they are 32
2310bit.
2311@item cookie64
2312    Set cookie size to 64 bit instead of the default 32
2313@item counter=off
2314    Force a 'cut-down' L2TPv3 with no counter as in
2315draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2316@item pincounter=on
2317    Work around broken counter handling in peer. This may also help on
2318networks which have packet reorder.
2319@item offset=@var{offset}
2320    Add an extra offset between header and data
2321@end table
2322
2323For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan
2324on the remote Linux host 1.2.3.4:
2325@example
2326# Setup tunnel on linux host using raw ip as encapsulation
2327# on 1.2.3.4
2328ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \
2329    encap udp udp_sport 16384 udp_dport 16384
2330ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \
2331    0xFFFFFFFF peer_session_id 0xFFFFFFFF
2332ifconfig vmtunnel0 mtu 1500
2333ifconfig vmtunnel0 up
2334brctl addif br-lan vmtunnel0
2335
2336
2337# on 4.3.2.1
2338# launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2339
2340qemu-system-i386 linux.img -device e1000,netdev=n1 \
2341    -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2342
2343@end example
2344
2345@item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2346Configure VDE backend to connect to PORT @var{n} of a vde switch running on host and
2347listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}
2348and MODE @var{octalmode} to change default ownership and permissions for
2349communication port. This option is only available if QEMU has been compiled
2350with vde support enabled.
2351
2352Example:
2353@example
2354# launch vde switch
2355vde_switch -F -sock /tmp/myswitch
2356# launch QEMU instance
2357qemu-system-i386 linux.img -nic vde,sock=/tmp/myswitch
2358@end example
2359
2360@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
2361
2362Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
2363be a unix domain socket backed one. The vhost-user uses a specifically defined
2364protocol to pass vhost ioctl replacement messages to an application on the other
2365end of the socket. On non-MSIX guests, the feature can be forced with
2366@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
2367be created for multiqueue vhost-user.
2368
2369Example:
2370@example
2371qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
2372     -numa node,memdev=mem \
2373     -chardev socket,id=chr0,path=/path/to/socket \
2374     -netdev type=vhost-user,id=net0,chardev=chr0 \
2375     -device virtio-net-pci,netdev=net0
2376@end example
2377
2378@item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}]
2379
2380Create a hub port on the emulated hub with ID @var{hubid}.
2381
2382The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2383single netdev. Alternatively, you can also connect the hubport to another
2384netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option.
2385
2386@item -net nic[,netdev=@var{nd}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}]
2387@findex -net
2388Legacy option to configure or create an on-board (or machine default) Network
2389Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e.
2390the default hub), or to the netdev @var{nd}.
2391The NIC is an e1000 by default on the PC target. Optionally, the MAC address
2392can be changed to @var{mac}, the device address set to @var{addr} (PCI cards
2393only), and a @var{name} can be assigned for use in monitor commands.
2394Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
2395that the card should have; this option currently only affects virtio cards; set
2396@var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
2397NIC is created.  QEMU can emulate several different models of network card.
2398Use @code{-net nic,model=help} for a list of available devices for your target.
2399
2400@item -net user|tap|bridge|socket|l2tpv3|vde[,...][,name=@var{name}]
2401Configure a host network backend (with the options corresponding to the same
2402@option{-netdev} option) and connect it to the emulated hub 0 (the default
2403hub). Use @var{name} to specify the name of the hub port.
2404ETEXI
2405
2406STEXI
2407@end table
2408ETEXI
2409DEFHEADING()
2410
2411DEFHEADING(Character device options:)
2412
2413DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
2414    "-chardev help\n"
2415    "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2416    "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2417    "         [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2418    "         [,logfile=PATH][,logappend=on|off][,tls-creds=ID] (tcp)\n"
2419    "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2420    "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2421    "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2422    "         [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2423    "         [,logfile=PATH][,logappend=on|off]\n"
2424    "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2425    "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2426    "         [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2427    "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2428    "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2429    "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2430#ifdef _WIN32
2431    "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2432    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2433#else
2434    "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2435    "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2436#endif
2437#ifdef CONFIG_BRLAPI
2438    "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2439#endif
2440#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
2441        || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
2442    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2443    "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2444#endif
2445#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
2446    "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2447    "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2448#endif
2449#if defined(CONFIG_SPICE)
2450    "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2451    "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2452#endif
2453    , QEMU_ARCH_ALL
2454)
2455
2456STEXI
2457
2458The general form of a character device option is:
2459@table @option
2460@item -chardev @var{backend},id=@var{id}[,mux=on|off][,@var{options}]
2461@findex -chardev
2462Backend is one of:
2463@option{null},
2464@option{socket},
2465@option{udp},
2466@option{msmouse},
2467@option{vc},
2468@option{ringbuf},
2469@option{file},
2470@option{pipe},
2471@option{console},
2472@option{serial},
2473@option{pty},
2474@option{stdio},
2475@option{braille},
2476@option{tty},
2477@option{parallel},
2478@option{parport},
2479@option{spicevmc},
2480@option{spiceport}.
2481The specific backend will determine the applicable options.
2482
2483Use @code{-chardev help} to print all available chardev backend types.
2484
2485All devices must have an id, which can be any string up to 127 characters long.
2486It is used to uniquely identify this device in other command line directives.
2487
2488A character device may be used in multiplexing mode by multiple front-ends.
2489Specify @option{mux=on} to enable this mode.
2490A multiplexer is a "1:N" device, and here the "1" end is your specified chardev
2491backend, and the "N" end is the various parts of QEMU that can talk to a chardev.
2492If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will
2493create a multiplexer with your specified ID, and you can then configure multiple
2494front ends to use that chardev ID for their input/output. Up to four different
2495front ends can be connected to a single multiplexed chardev. (Without
2496multiplexing enabled, a chardev can only be used by a single front end.)
2497For instance you could use this to allow a single stdio chardev to be used by
2498two serial ports and the QEMU monitor:
2499
2500@example
2501-chardev stdio,mux=on,id=char0 \
2502-mon chardev=char0,mode=readline \
2503-serial chardev:char0 \
2504-serial chardev:char0
2505@end example
2506
2507You can have more than one multiplexer in a system configuration; for instance
2508you could have a TCP port multiplexed between UART 0 and UART 1, and stdio
2509multiplexed between the QEMU monitor and a parallel port:
2510
2511@example
2512-chardev stdio,mux=on,id=char0 \
2513-mon chardev=char0,mode=readline \
2514-parallel chardev:char0 \
2515-chardev tcp,...,mux=on,id=char1 \
2516-serial chardev:char1 \
2517-serial chardev:char1
2518@end example
2519
2520When you're using a multiplexed character device, some escape sequences are
2521interpreted in the input. @xref{mux_keys, Keys in the character backend
2522multiplexer}.
2523
2524Note that some other command line options may implicitly create multiplexed
2525character backends; for instance @option{-serial mon:stdio} creates a
2526multiplexed stdio backend connected to the serial port and the QEMU monitor,
2527and @option{-nographic} also multiplexes the console and the monitor to
2528stdio.
2529
2530There is currently no support for multiplexing in the other direction
2531(where a single QEMU front end takes input and output from multiple chardevs).
2532
2533Every backend supports the @option{logfile} option, which supplies the path
2534to a file to record all data transmitted via the backend. The @option{logappend}
2535option controls whether the log file will be truncated or appended to when
2536opened.
2537
2538@end table
2539
2540The available backends are:
2541
2542@table @option
2543@item -chardev null,id=@var{id}
2544A void device. This device will not emit any data, and will drop any data it
2545receives. The null backend does not take any options.
2546
2547@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
2548
2549Create a two-way stream socket, which can be either a TCP or a unix socket. A
2550unix socket will be created if @option{path} is specified. Behaviour is
2551undefined if TCP options are specified for a unix socket.
2552
2553@option{server} specifies that the socket shall be a listening socket.
2554
2555@option{nowait} specifies that QEMU should not block waiting for a client to
2556connect to a listening socket.
2557
2558@option{telnet} specifies that traffic on the socket should interpret telnet
2559escape sequences.
2560
2561@option{websocket} specifies that the socket uses WebSocket protocol for
2562communication.
2563
2564@option{reconnect} sets the timeout for reconnecting on non-server sockets when
2565the remote end goes away.  qemu will delay this many seconds and then attempt
2566to reconnect.  Zero disables reconnecting, and is the default.
2567
2568@option{tls-creds} requests enablement of the TLS protocol for encryption,
2569and specifies the id of the TLS credentials to use for the handshake. The
2570credentials must be previously created with the @option{-object tls-creds}
2571argument.
2572
2573TCP and unix socket options are given below:
2574
2575@table @option
2576
2577@item TCP options: port=@var{port}[,host=@var{host}][,to=@var{to}][,ipv4][,ipv6][,nodelay]
2578
2579@option{host} for a listening socket specifies the local address to be bound.
2580For a connecting socket species the remote host to connect to. @option{host} is
2581optional for listening sockets. If not specified it defaults to @code{0.0.0.0}.
2582
2583@option{port} for a listening socket specifies the local port to be bound. For a
2584connecting socket specifies the port on the remote host to connect to.
2585@option{port} can be given as either a port number or a service name.
2586@option{port} is required.
2587
2588@option{to} is only relevant to listening sockets. If it is specified, and
2589@option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up
2590to and including @option{to} until it succeeds. @option{to} must be specified
2591as a port number.
2592
2593@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2594If neither is specified the socket may use either protocol.
2595
2596@option{nodelay} disables the Nagle algorithm.
2597
2598@item unix options: path=@var{path}
2599
2600@option{path} specifies the local path of the unix socket. @option{path} is
2601required.
2602
2603@end table
2604
2605@item -chardev udp,id=@var{id}[,host=@var{host}],port=@var{port}[,localaddr=@var{localaddr}][,localport=@var{localport}][,ipv4][,ipv6]
2606
2607Sends all traffic from the guest to a remote host over UDP.
2608
2609@option{host} specifies the remote host to connect to. If not specified it
2610defaults to @code{localhost}.
2611
2612@option{port} specifies the port on the remote host to connect to. @option{port}
2613is required.
2614
2615@option{localaddr} specifies the local address to bind to. If not specified it
2616defaults to @code{0.0.0.0}.
2617
2618@option{localport} specifies the local port to bind to. If not specified any
2619available local port will be used.
2620
2621@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2622If neither is specified the device may use either protocol.
2623
2624@item -chardev msmouse,id=@var{id}
2625
2626Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not
2627take any options.
2628
2629@item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
2630
2631Connect to a QEMU text console. @option{vc} may optionally be given a specific
2632size.
2633
2634@option{width} and @option{height} specify the width and height respectively of
2635the console, in pixels.
2636
2637@option{cols} and @option{rows} specify that the console be sized to fit a text
2638console with the given dimensions.
2639
2640@item -chardev ringbuf,id=@var{id}[,size=@var{size}]
2641
2642Create a ring buffer with fixed size @option{size}.
2643@var{size} must be a power of two and defaults to @code{64K}.
2644
2645@item -chardev file,id=@var{id},path=@var{path}
2646
2647Log all traffic received from the guest to a file.
2648
2649@option{path} specifies the path of the file to be opened. This file will be
2650created if it does not already exist, and overwritten if it does. @option{path}
2651is required.
2652
2653@item -chardev pipe,id=@var{id},path=@var{path}
2654
2655Create a two-way connection to the guest. The behaviour differs slightly between
2656Windows hosts and other hosts:
2657
2658On Windows, a single duplex pipe will be created at
2659@file{\\.pipe\@option{path}}.
2660
2661On other hosts, 2 pipes will be created called @file{@option{path}.in} and
2662@file{@option{path}.out}. Data written to @file{@option{path}.in} will be
2663received by the guest. Data written by the guest can be read from
2664@file{@option{path}.out}. QEMU will not create these fifos, and requires them to
2665be present.
2666
2667@option{path} forms part of the pipe path as described above. @option{path} is
2668required.
2669
2670@item -chardev console,id=@var{id}
2671
2672Send traffic from the guest to QEMU's standard output. @option{console} does not
2673take any options.
2674
2675@option{console} is only available on Windows hosts.
2676
2677@item -chardev serial,id=@var{id},path=@option{path}
2678
2679Send traffic from the guest to a serial device on the host.
2680
2681On Unix hosts serial will actually accept any tty device,
2682not only serial lines.
2683
2684@option{path} specifies the name of the serial device to open.
2685
2686@item -chardev pty,id=@var{id}
2687
2688Create a new pseudo-terminal on the host and connect to it. @option{pty} does
2689not take any options.
2690
2691@option{pty} is not available on Windows hosts.
2692
2693@item -chardev stdio,id=@var{id}[,signal=on|off]
2694Connect to standard input and standard output of the QEMU process.
2695
2696@option{signal} controls if signals are enabled on the terminal, that includes
2697exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
2698default, use @option{signal=off} to disable it.
2699
2700@item -chardev braille,id=@var{id}
2701
2702Connect to a local BrlAPI server. @option{braille} does not take any options.
2703
2704@item -chardev tty,id=@var{id},path=@var{path}
2705
2706@option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
2707DragonFlyBSD hosts.  It is an alias for @option{serial}.
2708
2709@option{path} specifies the path to the tty. @option{path} is required.
2710
2711@item -chardev parallel,id=@var{id},path=@var{path}
2712@itemx -chardev parport,id=@var{id},path=@var{path}
2713
2714@option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
2715
2716Connect to a local parallel port.
2717
2718@option{path} specifies the path to the parallel port device. @option{path} is
2719required.
2720
2721@item -chardev spicevmc,id=@var{id},debug=@var{debug},name=@var{name}
2722
2723@option{spicevmc} is only available when spice support is built in.
2724
2725@option{debug} debug level for spicevmc
2726
2727@option{name} name of spice channel to connect to
2728
2729Connect to a spice virtual machine channel, such as vdiport.
2730
2731@item -chardev spiceport,id=@var{id},debug=@var{debug},name=@var{name}
2732
2733@option{spiceport} is only available when spice support is built in.
2734
2735@option{debug} debug level for spicevmc
2736
2737@option{name} name of spice port to connect to
2738
2739Connect to a spice port, allowing a Spice client to handle the traffic
2740identified by a name (preferably a fqdn).
2741ETEXI
2742
2743STEXI
2744@end table
2745ETEXI
2746DEFHEADING()
2747
2748DEFHEADING(Bluetooth(R) options:)
2749STEXI
2750@table @option
2751ETEXI
2752
2753DEF("bt", HAS_ARG, QEMU_OPTION_bt, \
2754    "-bt hci,null    dumb bluetooth HCI - doesn't respond to commands\n" \
2755    "-bt hci,host[:id]\n" \
2756    "                use host's HCI with the given name\n" \
2757    "-bt hci[,vlan=n]\n" \
2758    "                emulate a standard HCI in virtual scatternet 'n'\n" \
2759    "-bt vhci[,vlan=n]\n" \
2760    "                add host computer to virtual scatternet 'n' using VHCI\n" \
2761    "-bt device:dev[,vlan=n]\n" \
2762    "                emulate a bluetooth device 'dev' in scatternet 'n'\n",
2763    QEMU_ARCH_ALL)
2764STEXI
2765@item -bt hci[...]
2766@findex -bt
2767Defines the function of the corresponding Bluetooth HCI.  -bt options
2768are matched with the HCIs present in the chosen machine type.  For
2769example when emulating a machine with only one HCI built into it, only
2770the first @code{-bt hci[...]} option is valid and defines the HCI's
2771logic.  The Transport Layer is decided by the machine type.  Currently
2772the machines @code{n800} and @code{n810} have one HCI and all other
2773machines have none.
2774
2775Note: This option and the whole bluetooth subsystem is considered as deprecated.
2776If you still use it, please send a mail to @email{qemu-devel@@nongnu.org} where
2777you describe your usecase.
2778
2779@anchor{bt-hcis}
2780The following three types are recognized:
2781
2782@table @option
2783@item -bt hci,null
2784(default) The corresponding Bluetooth HCI assumes no internal logic
2785and will not respond to any HCI commands or emit events.
2786
2787@item -bt hci,host[:@var{id}]
2788(@code{bluez} only) The corresponding HCI passes commands / events
2789to / from the physical HCI identified by the name @var{id} (default:
2790@code{hci0}) on the computer running QEMU.  Only available on @code{bluez}
2791capable systems like Linux.
2792
2793@item -bt hci[,vlan=@var{n}]
2794Add a virtual, standard HCI that will participate in the Bluetooth
2795scatternet @var{n} (default @code{0}).  Similarly to @option{-net}
2796VLANs, devices inside a bluetooth network @var{n} can only communicate
2797with other devices in the same network (scatternet).
2798@end table
2799
2800@item -bt vhci[,vlan=@var{n}]
2801(Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached
2802to the host bluetooth stack instead of to the emulated target.  This
2803allows the host and target machines to participate in a common scatternet
2804and communicate.  Requires the Linux @code{vhci} driver installed.  Can
2805be used as following:
2806
2807@example
2808qemu-system-i386 [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5
2809@end example
2810
2811@item -bt device:@var{dev}[,vlan=@var{n}]
2812Emulate a bluetooth device @var{dev} and place it in network @var{n}
2813(default @code{0}).  QEMU can only emulate one type of bluetooth devices
2814currently:
2815
2816@table @option
2817@item keyboard
2818Virtual wireless keyboard implementing the HIDP bluetooth profile.
2819@end table
2820ETEXI
2821
2822STEXI
2823@end table
2824ETEXI
2825DEFHEADING()
2826
2827#ifdef CONFIG_TPM
2828DEFHEADING(TPM device options:)
2829
2830DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
2831    "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
2832    "                use path to provide path to a character device; default is /dev/tpm0\n"
2833    "                use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
2834    "                not provided it will be searched for in /sys/class/misc/tpm?/device\n"
2835    "-tpmdev emulator,id=id,chardev=dev\n"
2836    "                configure the TPM device using chardev backend\n",
2837    QEMU_ARCH_ALL)
2838STEXI
2839
2840The general form of a TPM device option is:
2841@table @option
2842
2843@item -tpmdev @var{backend},id=@var{id}[,@var{options}]
2844@findex -tpmdev
2845
2846The specific backend type will determine the applicable options.
2847The @code{-tpmdev} option creates the TPM backend and requires a
2848@code{-device} option that specifies the TPM frontend interface model.
2849
2850Use @code{-tpmdev help} to print all available TPM backend types.
2851
2852@end table
2853
2854The available backends are:
2855
2856@table @option
2857
2858@item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path}
2859
2860(Linux-host only) Enable access to the host's TPM using the passthrough
2861driver.
2862
2863@option{path} specifies the path to the host's TPM device, i.e., on
2864a Linux host this would be @code{/dev/tpm0}.
2865@option{path} is optional and by default @code{/dev/tpm0} is used.
2866
2867@option{cancel-path} specifies the path to the host TPM device's sysfs
2868entry allowing for cancellation of an ongoing TPM command.
2869@option{cancel-path} is optional and by default QEMU will search for the
2870sysfs entry to use.
2871
2872Some notes about using the host's TPM with the passthrough driver:
2873
2874The TPM device accessed by the passthrough driver must not be
2875used by any other application on the host.
2876
2877Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
2878the VM's firmware (BIOS/UEFI) will not be able to initialize the
2879TPM again and may therefore not show a TPM-specific menu that would
2880otherwise allow the user to configure the TPM, e.g., allow the user to
2881enable/disable or activate/deactivate the TPM.
2882Further, if TPM ownership is released from within a VM then the host's TPM
2883will get disabled and deactivated. To enable and activate the
2884TPM again afterwards, the host has to be rebooted and the user is
2885required to enter the firmware's menu to enable and activate the TPM.
2886If the TPM is left disabled and/or deactivated most TPM commands will fail.
2887
2888To create a passthrough TPM use the following two options:
2889@example
2890-tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
2891@end example
2892Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
2893@code{tpmdev=tpm0} in the device option.
2894
2895@item -tpmdev emulator,id=@var{id},chardev=@var{dev}
2896
2897(Linux-host only) Enable access to a TPM emulator using Unix domain socket based
2898chardev backend.
2899
2900@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
2901
2902To create a TPM emulator backend device with chardev socket backend:
2903@example
2904
2905-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
2906
2907@end example
2908
2909ETEXI
2910
2911STEXI
2912@end table
2913ETEXI
2914DEFHEADING()
2915
2916#endif
2917
2918DEFHEADING(Linux/Multiboot boot specific:)
2919STEXI
2920
2921When using these options, you can use a given Linux or Multiboot
2922kernel without installing it in the disk image. It can be useful
2923for easier testing of various kernels.
2924
2925@table @option
2926ETEXI
2927
2928DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
2929    "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
2930STEXI
2931@item -kernel @var{bzImage}
2932@findex -kernel
2933Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
2934or in multiboot format.
2935ETEXI
2936
2937DEF("append", HAS_ARG, QEMU_OPTION_append, \
2938    "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
2939STEXI
2940@item -append @var{cmdline}
2941@findex -append
2942Use @var{cmdline} as kernel command line
2943ETEXI
2944
2945DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
2946           "-initrd file    use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
2947STEXI
2948@item -initrd @var{file}
2949@findex -initrd
2950Use @var{file} as initial ram disk.
2951
2952@item -initrd "@var{file1} arg=foo,@var{file2}"
2953
2954This syntax is only available with multiboot.
2955
2956Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
2957first module.
2958ETEXI
2959
2960DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
2961    "-dtb    file    use 'file' as device tree image\n", QEMU_ARCH_ALL)
2962STEXI
2963@item -dtb @var{file}
2964@findex -dtb
2965Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
2966on boot.
2967ETEXI
2968
2969STEXI
2970@end table
2971ETEXI
2972DEFHEADING()
2973
2974DEFHEADING(Debug/Expert options:)
2975STEXI
2976@table @option
2977ETEXI
2978
2979DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
2980    "-fw_cfg [name=]<name>,file=<file>\n"
2981    "                add named fw_cfg entry with contents from file\n"
2982    "-fw_cfg [name=]<name>,string=<str>\n"
2983    "                add named fw_cfg entry with contents from string\n",
2984    QEMU_ARCH_ALL)
2985STEXI
2986
2987@item -fw_cfg [name=]@var{name},file=@var{file}
2988@findex -fw_cfg
2989Add named fw_cfg entry with contents from file @var{file}.
2990
2991@item -fw_cfg [name=]@var{name},string=@var{str}
2992Add named fw_cfg entry with contents from string @var{str}.
2993
2994The terminating NUL character of the contents of @var{str} will not be
2995included as part of the fw_cfg item data. To insert contents with
2996embedded NUL characters, you have to use the @var{file} parameter.
2997
2998The fw_cfg entries are passed by QEMU through to the guest.
2999
3000Example:
3001@example
3002    -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3003@end example
3004creates an fw_cfg entry named opt/com.mycompany/blob with contents
3005from ./my_blob.bin.
3006
3007ETEXI
3008
3009DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3010    "-serial dev     redirect the serial port to char device 'dev'\n",
3011    QEMU_ARCH_ALL)
3012STEXI
3013@item -serial @var{dev}
3014@findex -serial
3015Redirect the virtual serial port to host character device
3016@var{dev}. The default device is @code{vc} in graphical mode and
3017@code{stdio} in non graphical mode.
3018
3019This option can be used several times to simulate up to 4 serial
3020ports.
3021
3022Use @code{-serial none} to disable all serial ports.
3023
3024Available character devices are:
3025@table @option
3026@item vc[:@var{W}x@var{H}]
3027Virtual console. Optionally, a width and height can be given in pixel with
3028@example
3029vc:800x600
3030@end example
3031It is also possible to specify width or height in characters:
3032@example
3033vc:80Cx24C
3034@end example
3035@item pty
3036[Linux only] Pseudo TTY (a new PTY is automatically allocated)
3037@item none
3038No device is allocated.
3039@item null
3040void device
3041@item chardev:@var{id}
3042Use a named character device defined with the @code{-chardev} option.
3043@item /dev/XXX
3044[Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3045parameters are set according to the emulated ones.
3046@item /dev/parport@var{N}
3047[Linux only, parallel port only] Use host parallel port
3048@var{N}. Currently SPP and EPP parallel port features can be used.
3049@item file:@var{filename}
3050Write output to @var{filename}. No character can be read.
3051@item stdio
3052[Unix only] standard input/output
3053@item pipe:@var{filename}
3054name pipe @var{filename}
3055@item COM@var{n}
3056[Windows only] Use host serial port @var{n}
3057@item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3058This implements UDP Net Console.
3059When @var{remote_host} or @var{src_ip} are not specified
3060they default to @code{0.0.0.0}.
3061When not using a specified @var{src_port} a random port is automatically chosen.
3062
3063If you just want a simple readonly console you can use @code{netcat} or
3064@code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3065@code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3066will appear in the netconsole session.
3067
3068If you plan to send characters back via netconsole or you want to stop
3069and start QEMU a lot of times, you should have QEMU use the same
3070source port each time by using something like @code{-serial
3071udp::4555@@:4556} to QEMU. Another approach is to use a patched
3072version of netcat which can listen to a TCP port and send and receive
3073characters via udp.  If you have a patched version of netcat which
3074activates telnet remote echo and single char transfer, then you can
3075use the following options to set up a netcat redirector to allow
3076telnet on port 5555 to access the QEMU port.
3077@table @code
3078@item QEMU Options:
3079-serial udp::4555@@:4556
3080@item netcat options:
3081-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3082@item telnet options:
3083localhost 5555
3084@end table
3085
3086@item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3087The TCP Net Console has two modes of operation.  It can send the serial
3088I/O to a location or wait for a connection from a location.  By default
3089the TCP Net Console is sent to @var{host} at the @var{port}.  If you use
3090the @var{server} option QEMU will wait for a client socket application
3091to connect to the port before continuing, unless the @code{nowait}
3092option was specified.  The @code{nodelay} option disables the Nagle buffering
3093algorithm.  The @code{reconnect} option only applies if @var{noserver} is
3094set, if the connection goes down it will attempt to reconnect at the
3095given interval.  If @var{host} is omitted, 0.0.0.0 is assumed. Only
3096one TCP connection at a time is accepted. You can use @code{telnet} to
3097connect to the corresponding character device.
3098@table @code
3099@item Example to send tcp console to 192.168.0.2 port 4444
3100-serial tcp:192.168.0.2:4444
3101@item Example to listen and wait on port 4444 for connection
3102-serial tcp::4444,server
3103@item Example to not wait and listen on ip 192.168.0.100 port 4444
3104-serial tcp:192.168.0.100:4444,server,nowait
3105@end table
3106
3107@item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3108The telnet protocol is used instead of raw tcp sockets.  The options
3109work the same as if you had specified @code{-serial tcp}.  The
3110difference is that the port acts like a telnet server or client using
3111telnet option negotiation.  This will also allow you to send the
3112MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3113sequence.  Typically in unix telnet you do it with Control-] and then
3114type "send break" followed by pressing the enter key.
3115
3116@item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
3117The WebSocket protocol is used instead of raw tcp socket. The port acts as
3118a WebSocket server. Client mode is not supported.
3119
3120@item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3121A unix domain socket is used instead of a tcp socket.  The option works the
3122same as if you had specified @code{-serial tcp} except the unix domain socket
3123@var{path} is used for connections.
3124
3125@item mon:@var{dev_string}
3126This is a special option to allow the monitor to be multiplexed onto
3127another serial port.  The monitor is accessed with key sequence of
3128@key{Control-a} and then pressing @key{c}.
3129@var{dev_string} should be any one of the serial devices specified
3130above.  An example to multiplex the monitor onto a telnet server
3131listening on port 4444 would be:
3132@table @code
3133@item -serial mon:telnet::4444,server,nowait
3134@end table
3135When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3136QEMU any more but will be passed to the guest instead.
3137
3138@item braille
3139Braille device.  This will use BrlAPI to display the braille output on a real
3140or fake device.
3141
3142@item msmouse
3143Three button serial mouse. Configure the guest to use Microsoft protocol.
3144@end table
3145ETEXI
3146
3147DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3148    "-parallel dev   redirect the parallel port to char device 'dev'\n",
3149    QEMU_ARCH_ALL)
3150STEXI
3151@item -parallel @var{dev}
3152@findex -parallel
3153Redirect the virtual parallel port to host device @var{dev} (same
3154devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3155be used to use hardware devices connected on the corresponding host
3156parallel port.
3157
3158This option can be used several times to simulate up to 3 parallel
3159ports.
3160
3161Use @code{-parallel none} to disable all parallel ports.
3162ETEXI
3163
3164DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3165    "-monitor dev    redirect the monitor to char device 'dev'\n",
3166    QEMU_ARCH_ALL)
3167STEXI
3168@item -monitor @var{dev}
3169@findex -monitor
3170Redirect the monitor to host device @var{dev} (same devices as the
3171serial port).
3172The default device is @code{vc} in graphical mode and @code{stdio} in
3173non graphical mode.
3174Use @code{-monitor none} to disable the default monitor.
3175ETEXI
3176DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3177    "-qmp dev        like -monitor but opens in 'control' mode\n",
3178    QEMU_ARCH_ALL)
3179STEXI
3180@item -qmp @var{dev}
3181@findex -qmp
3182Like -monitor but opens in 'control' mode.
3183ETEXI
3184DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3185    "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3186    QEMU_ARCH_ALL)
3187STEXI
3188@item -qmp-pretty @var{dev}
3189@findex -qmp-pretty
3190Like -qmp but uses pretty JSON formatting.
3191ETEXI
3192
3193DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3194    "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3195STEXI
3196@item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]
3197@findex -mon
3198Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing
3199easing human reading and debugging.
3200ETEXI
3201
3202DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3203    "-debugcon dev   redirect the debug console to char device 'dev'\n",
3204    QEMU_ARCH_ALL)
3205STEXI
3206@item -debugcon @var{dev}
3207@findex -debugcon
3208Redirect the debug console to host device @var{dev} (same devices as the
3209serial port).  The debug console is an I/O port which is typically port
32100xe9; writing to that I/O port sends output to this device.
3211The default device is @code{vc} in graphical mode and @code{stdio} in
3212non graphical mode.
3213ETEXI
3214
3215DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3216    "-pidfile file   write PID to 'file'\n", QEMU_ARCH_ALL)
3217STEXI
3218@item -pidfile @var{file}
3219@findex -pidfile
3220Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3221from a script.
3222ETEXI
3223
3224DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3225    "-singlestep     always run in singlestep mode\n", QEMU_ARCH_ALL)
3226STEXI
3227@item -singlestep
3228@findex -singlestep
3229Run the emulation in single step mode.
3230ETEXI
3231
3232DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3233    "--preconfig     pause QEMU before machine is initialized (experimental)\n",
3234    QEMU_ARCH_ALL)
3235STEXI
3236@item --preconfig
3237@findex --preconfig
3238Pause QEMU for interactive configuration before the machine is created,
3239which allows querying and configuring properties that will affect
3240machine initialization.  Use QMP command 'x-exit-preconfig' to exit
3241the preconfig state and move to the next state (i.e. run guest if -S
3242isn't used or pause the second time if -S is used).  This option is
3243experimental.
3244ETEXI
3245
3246DEF("S", 0, QEMU_OPTION_S, \
3247    "-S              freeze CPU at startup (use 'c' to start execution)\n",
3248    QEMU_ARCH_ALL)
3249STEXI
3250@item -S
3251@findex -S
3252Do not start CPU at startup (you must type 'c' in the monitor).
3253ETEXI
3254
3255DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
3256    "-realtime [mlock=on|off]\n"
3257    "                run qemu with realtime features\n"
3258    "                mlock=on|off controls mlock support (default: on)\n",
3259    QEMU_ARCH_ALL)
3260STEXI
3261@item -realtime mlock=on|off
3262@findex -realtime
3263Run qemu with realtime features.
3264mlocking qemu and guest memory can be enabled via @option{mlock=on}
3265(enabled by default).
3266ETEXI
3267
3268DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3269    "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3270    "                run qemu with overcommit hints\n"
3271    "                mem-lock=on|off controls memory lock support (default: off)\n"
3272    "                cpu-pm=on|off controls cpu power management (default: off)\n",
3273    QEMU_ARCH_ALL)
3274STEXI
3275@item -overcommit mem-lock=on|off
3276@item -overcommit cpu-pm=on|off
3277@findex -overcommit
3278Run qemu with hints about host resource overcommit. The default is
3279to assume that host overcommits all resources.
3280
3281Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3282by default).  This works when host memory is not overcommitted and reduces the
3283worst-case latency for guest.  This is equivalent to @option{realtime}.
3284
3285Guest ability to manage power state of host cpus (increasing latency for other
3286processes on the same host cpu, but decreasing latency for guest) can be
3287enabled via @option{cpu-pm=on} (disabled by default).  This works best when
3288host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3289utilization will be incorrect, not taking into account guest idle time.
3290ETEXI
3291
3292DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3293    "-gdb dev        wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
3294STEXI
3295@item -gdb @var{dev}
3296@findex -gdb
3297Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3298connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3299stdio are reasonable use case. The latter is allowing to start QEMU from
3300within gdb and establish the connection via a pipe:
3301@example
3302(gdb) target remote | exec qemu-system-i386 -gdb stdio ...
3303@end example
3304ETEXI
3305
3306DEF("s", 0, QEMU_OPTION_s, \
3307    "-s              shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3308    QEMU_ARCH_ALL)
3309STEXI
3310@item -s
3311@findex -s
3312Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3313(@pxref{gdb_usage}).
3314ETEXI
3315
3316DEF("d", HAS_ARG, QEMU_OPTION_d, \
3317    "-d item1,...    enable logging of specified items (use '-d help' for a list of log items)\n",
3318    QEMU_ARCH_ALL)
3319STEXI
3320@item -d @var{item1}[,...]
3321@findex -d
3322Enable logging of specified items. Use '-d help' for a list of log items.
3323ETEXI
3324
3325DEF("D", HAS_ARG, QEMU_OPTION_D, \
3326    "-D logfile      output log to logfile (default stderr)\n",
3327    QEMU_ARCH_ALL)
3328STEXI
3329@item -D @var{logfile}
3330@findex -D
3331Output log in @var{logfile} instead of to stderr
3332ETEXI
3333
3334DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3335    "-dfilter range,..  filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3336    QEMU_ARCH_ALL)
3337STEXI
3338@item -dfilter @var{range1}[,...]
3339@findex -dfilter
3340Filter debug output to that relevant to a range of target addresses. The filter
3341spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3342@var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3343addresses and sizes required. For example:
3344@example
3345    -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3346@end example
3347Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3348the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3349block starting at 0xffffffc00005f000.
3350ETEXI
3351
3352DEF("L", HAS_ARG, QEMU_OPTION_L, \
3353    "-L path         set the directory for the BIOS, VGA BIOS and keymaps\n",
3354    QEMU_ARCH_ALL)
3355STEXI
3356@item -L  @var{path}
3357@findex -L
3358Set the directory for the BIOS, VGA BIOS and keymaps.
3359
3360To list all the data directories, use @code{-L help}.
3361ETEXI
3362
3363DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3364    "-bios file      set the filename for the BIOS\n", QEMU_ARCH_ALL)
3365STEXI
3366@item -bios @var{file}
3367@findex -bios
3368Set the filename for the BIOS.
3369ETEXI
3370
3371DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3372    "-enable-kvm     enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3373STEXI
3374@item -enable-kvm
3375@findex -enable-kvm
3376Enable KVM full virtualization support. This option is only available
3377if KVM support is enabled when compiling.
3378ETEXI
3379
3380DEF("enable-hax", 0, QEMU_OPTION_enable_hax, \
3381    "-enable-hax     enable HAX virtualization support\n", QEMU_ARCH_I386)
3382STEXI
3383@item -enable-hax
3384@findex -enable-hax
3385Enable HAX (Hardware-based Acceleration eXecution) support. This option
3386is only available if HAX support is enabled when compiling. HAX is only
3387applicable to MAC and Windows platform, and thus does not conflict with
3388KVM. This option is deprecated, use @option{-accel hax} instead.
3389ETEXI
3390
3391DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3392    "-xen-domid id   specify xen guest domain id\n", QEMU_ARCH_ALL)
3393DEF("xen-create", 0, QEMU_OPTION_xen_create,
3394    "-xen-create     create domain using xen hypercalls, bypassing xend\n"
3395    "                warning: should not be used when xend is in use\n",
3396    QEMU_ARCH_ALL)
3397DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3398    "-xen-attach     attach to existing xen domain\n"
3399    "                xend will use this when starting QEMU\n",
3400    QEMU_ARCH_ALL)
3401DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3402    "-xen-domid-restrict     restrict set of available xen operations\n"
3403    "                        to specified domain id. (Does not affect\n"
3404    "                        xenpv machine type).\n",
3405    QEMU_ARCH_ALL)
3406STEXI
3407@item -xen-domid @var{id}
3408@findex -xen-domid
3409Specify xen guest domain @var{id} (XEN only).
3410@item -xen-create
3411@findex -xen-create
3412Create domain using xen hypercalls, bypassing xend.
3413Warning: should not be used when xend is in use (XEN only).
3414@item -xen-attach
3415@findex -xen-attach
3416Attach to existing xen domain.
3417xend will use this when starting QEMU (XEN only).
3418@findex -xen-domid-restrict
3419Restrict set of available xen operations to specified domain id (XEN only).
3420ETEXI
3421
3422DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3423    "-no-reboot      exit instead of rebooting\n", QEMU_ARCH_ALL)
3424STEXI
3425@item -no-reboot
3426@findex -no-reboot
3427Exit instead of rebooting.
3428ETEXI
3429
3430DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3431    "-no-shutdown    stop before shutdown\n", QEMU_ARCH_ALL)
3432STEXI
3433@item -no-shutdown
3434@findex -no-shutdown
3435Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3436This allows for instance switching to monitor to commit changes to the
3437disk image.
3438ETEXI
3439
3440DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
3441    "-loadvm [tag|id]\n" \
3442    "                start right away with a saved state (loadvm in monitor)\n",
3443    QEMU_ARCH_ALL)
3444STEXI
3445@item -loadvm @var{file}
3446@findex -loadvm
3447Start right away with a saved state (@code{loadvm} in monitor)
3448ETEXI
3449
3450#ifndef _WIN32
3451DEF("daemonize", 0, QEMU_OPTION_daemonize, \
3452    "-daemonize      daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
3453#endif
3454STEXI
3455@item -daemonize
3456@findex -daemonize
3457Daemonize the QEMU process after initialization.  QEMU will not detach from
3458standard IO until it is ready to receive connections on any of its devices.
3459This option is a useful way for external programs to launch QEMU without having
3460to cope with initialization race conditions.
3461ETEXI
3462
3463DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
3464    "-option-rom rom load a file, rom, into the option ROM space\n",
3465    QEMU_ARCH_ALL)
3466STEXI
3467@item -option-rom @var{file}
3468@findex -option-rom
3469Load the contents of @var{file} as an option ROM.
3470This option is useful to load things like EtherBoot.
3471ETEXI
3472
3473HXCOMM Silently ignored for compatibility
3474DEF("clock", HAS_ARG, QEMU_OPTION_clock, "", QEMU_ARCH_ALL)
3475
3476DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
3477    "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
3478    "                set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
3479    QEMU_ARCH_ALL)
3480
3481STEXI
3482
3483@item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew]
3484@findex -rtc
3485Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3486UTC or local time, respectively. @code{localtime} is required for correct date in
3487MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the
3488format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3489
3490By default the RTC is driven by the host system time. This allows using of the
3491RTC as accurate reference clock inside the guest, specifically if the host
3492time is smoothly following an accurate external reference clock, e.g. via NTP.
3493If you want to isolate the guest time from the host, you can set @option{clock}
3494to @code{rt} instead, which provides a host monotonic clock if host support it.
3495To even prevent the RTC from progressing during suspension, you can set @option{clock}
3496to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in
3497icount mode in order to preserve determinism; however, note that in icount mode
3498the speed of the virtual clock is variable and can in general differ from the
3499host clock.
3500
3501Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3502specifically with Windows' ACPI HAL. This option will try to figure out how
3503many timer interrupts were not processed by the Windows guest and will
3504re-inject them.
3505ETEXI
3506
3507DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
3508    "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \
3509    "                enable virtual instruction counter with 2^N clock ticks per\n" \
3510    "                instruction, enable aligning the host and virtual clocks\n" \
3511    "                or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
3512STEXI
3513@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3514@findex -icount
3515Enable virtual instruction counter.  The virtual cpu will execute one
3516instruction every 2^@var{N} ns of virtual time.  If @code{auto} is specified
3517then the virtual cpu speed will be automatically adjusted to keep virtual
3518time within a few seconds of real time.
3519
3520When the virtual cpu is sleeping, the virtual time will advance at default
3521speed unless @option{sleep=on|off} is specified.
3522With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3523instantly whenever the virtual cpu goes to sleep mode and will not advance
3524if no timer is enabled. This behavior give deterministic execution times from
3525the guest point of view.
3526
3527Note that while this option can give deterministic behavior, it does not
3528provide cycle accurate emulation.  Modern CPUs contain superscalar out of
3529order cores with complex cache hierarchies.  The number of instructions
3530executed often has little or no correlation with actual performance.
3531
3532@option{align=on} will activate the delay algorithm which will try
3533to synchronise the host clock and the virtual clock. The goal is to
3534have a guest running at the real frequency imposed by the shift option.
3535Whenever the guest clock is behind the host clock and if
3536@option{align=on} is specified then we print a message to the user
3537to inform about the delay.
3538Currently this option does not work when @option{shift} is @code{auto}.
3539Note: The sync algorithm will work for those shift values for which
3540the guest clock runs ahead of the host clock. Typically this happens
3541when the shift value is high (how high depends on the host machine).
3542
3543When @option{rr} option is specified deterministic record/replay is enabled.
3544Replay log is written into @var{filename} file in record mode and
3545read from this file in replay mode.
3546
3547Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3548at the start of execution recording. In replay mode this option is used
3549to load the initial VM state.
3550ETEXI
3551
3552DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
3553    "-watchdog model\n" \
3554    "                enable virtual hardware watchdog [default=none]\n",
3555    QEMU_ARCH_ALL)
3556STEXI
3557@item -watchdog @var{model}
3558@findex -watchdog
3559Create a virtual hardware watchdog device.  Once enabled (by a guest
3560action), the watchdog must be periodically polled by an agent inside
3561the guest or else the guest will be restarted. Choose a model for
3562which your guest has drivers.
3563
3564The @var{model} is the model of hardware watchdog to emulate. Use
3565@code{-watchdog help} to list available hardware models. Only one
3566watchdog can be enabled for a guest.
3567
3568The following models may be available:
3569@table @option
3570@item ib700
3571iBASE 700 is a very simple ISA watchdog with a single timer.
3572@item i6300esb
3573Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3574dual-timer watchdog.
3575@item diag288
3576A virtual watchdog for s390x backed by the diagnose 288 hypercall
3577(currently KVM only).
3578@end table
3579ETEXI
3580
3581DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
3582    "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
3583    "                action when watchdog fires [default=reset]\n",
3584    QEMU_ARCH_ALL)
3585STEXI
3586@item -watchdog-action @var{action}
3587@findex -watchdog-action
3588
3589The @var{action} controls what QEMU will do when the watchdog timer
3590expires.
3591The default is
3592@code{reset} (forcefully reset the guest).
3593Other possible actions are:
3594@code{shutdown} (attempt to gracefully shutdown the guest),
3595@code{poweroff} (forcefully poweroff the guest),
3596@code{inject-nmi} (inject a NMI into the guest),
3597@code{pause} (pause the guest),
3598@code{debug} (print a debug message and continue), or
3599@code{none} (do nothing).
3600
3601Note that the @code{shutdown} action requires that the guest responds
3602to ACPI signals, which it may not be able to do in the sort of
3603situations where the watchdog would have expired, and thus
3604@code{-watchdog-action shutdown} is not recommended for production use.
3605
3606Examples:
3607
3608@table @code
3609@item -watchdog i6300esb -watchdog-action pause
3610@itemx -watchdog ib700
3611@end table
3612ETEXI
3613
3614DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
3615    "-echr chr       set terminal escape character instead of ctrl-a\n",
3616    QEMU_ARCH_ALL)
3617STEXI
3618
3619@item -echr @var{numeric_ascii_value}
3620@findex -echr
3621Change the escape character used for switching to the monitor when using
3622monitor and serial sharing.  The default is @code{0x01} when using the
3623@code{-nographic} option.  @code{0x01} is equal to pressing
3624@code{Control-a}.  You can select a different character from the ascii
3625control keys where 1 through 26 map to Control-a through Control-z.  For
3626instance you could use the either of the following to change the escape
3627character to Control-t.
3628@table @code
3629@item -echr 0x14
3630@itemx -echr 20
3631@end table
3632ETEXI
3633
3634DEF("virtioconsole", HAS_ARG, QEMU_OPTION_virtiocon, \
3635    "-virtioconsole c\n" \
3636    "                set virtio console\n", QEMU_ARCH_ALL)
3637STEXI
3638@item -virtioconsole @var{c}
3639@findex -virtioconsole
3640Set virtio console.
3641This option is deprecated, please use @option{-device virtconsole} instead.
3642ETEXI
3643
3644DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
3645    "-show-cursor    show cursor\n", QEMU_ARCH_ALL)
3646STEXI
3647@item -show-cursor
3648@findex -show-cursor
3649Show cursor.
3650ETEXI
3651
3652DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
3653    "-tb-size n      set TB size\n", QEMU_ARCH_ALL)
3654STEXI
3655@item -tb-size @var{n}
3656@findex -tb-size
3657Set TB size.
3658ETEXI
3659
3660DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
3661    "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \
3662    "-incoming rdma:host:port[,ipv4][,ipv6]\n" \
3663    "-incoming unix:socketpath\n" \
3664    "                prepare for incoming migration, listen on\n" \
3665    "                specified protocol and socket address\n" \
3666    "-incoming fd:fd\n" \
3667    "-incoming exec:cmdline\n" \
3668    "                accept incoming migration on given file descriptor\n" \
3669    "                or from given external command\n" \
3670    "-incoming defer\n" \
3671    "                wait for the URI to be specified via migrate_incoming\n",
3672    QEMU_ARCH_ALL)
3673STEXI
3674@item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
3675@itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
3676@findex -incoming
3677Prepare for incoming migration, listen on a given tcp port.
3678
3679@item -incoming unix:@var{socketpath}
3680Prepare for incoming migration, listen on a given unix socket.
3681
3682@item -incoming fd:@var{fd}
3683Accept incoming migration from a given filedescriptor.
3684
3685@item -incoming exec:@var{cmdline}
3686Accept incoming migration as an output from specified external command.
3687
3688@item -incoming defer
3689Wait for the URI to be specified via migrate_incoming.  The monitor can
3690be used to change settings (such as migration parameters) prior to issuing
3691the migrate_incoming to allow the migration to begin.
3692ETEXI
3693
3694DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
3695    "-only-migratable     allow only migratable devices\n", QEMU_ARCH_ALL)
3696STEXI
3697@item -only-migratable
3698@findex -only-migratable
3699Only allow migratable devices. Devices will not be allowed to enter an
3700unmigratable state.
3701ETEXI
3702
3703DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
3704    "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
3705STEXI
3706@item -nodefaults
3707@findex -nodefaults
3708Don't create default devices. Normally, QEMU sets the default devices like serial
3709port, parallel port, virtual console, monitor device, VGA adapter, floppy and
3710CD-ROM drive and others. The @code{-nodefaults} option will disable all those
3711default devices.
3712ETEXI
3713
3714#ifndef _WIN32
3715DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
3716    "-chroot dir     chroot to dir just before starting the VM\n",
3717    QEMU_ARCH_ALL)
3718#endif
3719STEXI
3720@item -chroot @var{dir}
3721@findex -chroot
3722Immediately before starting guest execution, chroot to the specified
3723directory.  Especially useful in combination with -runas.
3724ETEXI
3725
3726#ifndef _WIN32
3727DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
3728    "-runas user     change to user id user just before starting the VM\n" \
3729    "                user can be numeric uid:gid instead\n",
3730    QEMU_ARCH_ALL)
3731#endif
3732STEXI
3733@item -runas @var{user}
3734@findex -runas
3735Immediately before starting guest execution, drop root privileges, switching
3736to the specified user.
3737ETEXI
3738
3739DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
3740    "-prom-env variable=value\n"
3741    "                set OpenBIOS nvram variables\n",
3742    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
3743STEXI
3744@item -prom-env @var{variable}=@var{value}
3745@findex -prom-env
3746Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
3747ETEXI
3748DEF("semihosting", 0, QEMU_OPTION_semihosting,
3749    "-semihosting    semihosting mode\n",
3750    QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3751    QEMU_ARCH_MIPS)
3752STEXI
3753@item -semihosting
3754@findex -semihosting
3755Enable semihosting mode (ARM, M68K, Xtensa, MIPS only).
3756ETEXI
3757DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
3758    "-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
3759    "                semihosting configuration\n",
3760QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3761QEMU_ARCH_MIPS)
3762STEXI
3763@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
3764@findex -semihosting-config
3765Enable and configure semihosting (ARM, M68K, Xtensa, MIPS only).
3766@table @option
3767@item target=@code{native|gdb|auto}
3768Defines where the semihosting calls will be addressed, to QEMU (@code{native})
3769or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
3770during debug sessions and @code{native} otherwise.
3771@item arg=@var{str1},arg=@var{str2},...
3772Allows the user to pass input arguments, and can be used multiple times to build
3773up a list. The old-style @code{-kernel}/@code{-append} method of passing a
3774command line is still supported for backward compatibility. If both the
3775@code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
3776specified, the former is passed to semihosting as it always takes precedence.
3777@end table
3778ETEXI
3779DEF("old-param", 0, QEMU_OPTION_old_param,
3780    "-old-param      old param mode\n", QEMU_ARCH_ARM)
3781STEXI
3782@item -old-param
3783@findex -old-param (ARM)
3784Old param mode (ARM only).
3785ETEXI
3786
3787DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
3788    "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
3789    "          [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
3790    "                Enable seccomp mode 2 system call filter (default 'off').\n" \
3791    "                use 'obsolete' to allow obsolete system calls that are provided\n" \
3792    "                    by the kernel, but typically no longer used by modern\n" \
3793    "                    C library implementations.\n" \
3794    "                use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
3795    "                    its privileges by blacklisting all set*uid|gid system calls.\n" \
3796    "                    The value 'children' will deny set*uid|gid system calls for\n" \
3797    "                    main QEMU process but will allow forks and execves to run unprivileged\n" \
3798    "                use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
3799    "                     blacklisting *fork and execve\n" \
3800    "                use 'resourcecontrol' to disable process affinity and schedular priority\n",
3801    QEMU_ARCH_ALL)
3802STEXI
3803@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
3804@findex -sandbox
3805Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
3806disable it.  The default is 'off'.
3807@table @option
3808@item obsolete=@var{string}
3809Enable Obsolete system calls
3810@item elevateprivileges=@var{string}
3811Disable set*uid|gid system calls
3812@item spawn=@var{string}
3813Disable *fork and execve
3814@item resourcecontrol=@var{string}
3815Disable process affinity and schedular priority
3816@end table
3817ETEXI
3818
3819DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
3820    "-readconfig <file>\n", QEMU_ARCH_ALL)
3821STEXI
3822@item -readconfig @var{file}
3823@findex -readconfig
3824Read device configuration from @var{file}. This approach is useful when you want to spawn
3825QEMU process with many command line options but you don't want to exceed the command line
3826character limit.
3827ETEXI
3828DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
3829    "-writeconfig <file>\n"
3830    "                read/write config file\n", QEMU_ARCH_ALL)
3831STEXI
3832@item -writeconfig @var{file}
3833@findex -writeconfig
3834Write device configuration to @var{file}. The @var{file} can be either filename to save
3835command line and device configuration into file or dash @code{-}) character to print the
3836output to stdout. This can be later used as input file for @code{-readconfig} option.
3837ETEXI
3838
3839DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
3840    "-no-user-config\n"
3841    "                do not load default user-provided config files at startup\n",
3842    QEMU_ARCH_ALL)
3843STEXI
3844@item -no-user-config
3845@findex -no-user-config
3846The @code{-no-user-config} option makes QEMU not load any of the user-provided
3847config files on @var{sysconfdir}.
3848ETEXI
3849
3850DEF("trace", HAS_ARG, QEMU_OPTION_trace,
3851    "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
3852    "                specify tracing options\n",
3853    QEMU_ARCH_ALL)
3854STEXI
3855HXCOMM This line is not accurate, as some sub-options are backend-specific but
3856HXCOMM HX does not support conditional compilation of text.
3857@item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
3858@findex -trace
3859@include qemu-option-trace.texi
3860ETEXI
3861
3862HXCOMM Internal use
3863DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
3864DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
3865
3866#ifdef __linux__
3867DEF("enable-fips", 0, QEMU_OPTION_enablefips,
3868    "-enable-fips    enable FIPS 140-2 compliance\n",
3869    QEMU_ARCH_ALL)
3870#endif
3871STEXI
3872@item -enable-fips
3873@findex -enable-fips
3874Enable FIPS 140-2 compliance mode.
3875ETEXI
3876
3877HXCOMM Deprecated by -machine accel=tcg property
3878DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
3879
3880DEF("msg", HAS_ARG, QEMU_OPTION_msg,
3881    "-msg timestamp[=on|off]\n"
3882    "                change the format of messages\n"
3883    "                on|off controls leading timestamps (default:on)\n",
3884    QEMU_ARCH_ALL)
3885STEXI
3886@item -msg timestamp[=on|off]
3887@findex -msg
3888prepend a timestamp to each log message.(default:on)
3889ETEXI
3890
3891DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
3892    "-dump-vmstate <file>\n"
3893    "                Output vmstate information in JSON format to file.\n"
3894    "                Use the scripts/vmstate-static-checker.py file to\n"
3895    "                check for possible regressions in migration code\n"
3896    "                by comparing two such vmstate dumps.\n",
3897    QEMU_ARCH_ALL)
3898STEXI
3899@item -dump-vmstate @var{file}
3900@findex -dump-vmstate
3901Dump json-encoded vmstate information for current machine type to file
3902in @var{file}
3903ETEXI
3904
3905DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
3906    "-enable-sync-profile\n"
3907    "                enable synchronization profiling\n",
3908    QEMU_ARCH_ALL)
3909STEXI
3910@item -enable-sync-profile
3911@findex -enable-sync-profile
3912Enable synchronization profiling.
3913ETEXI
3914
3915STEXI
3916@end table
3917ETEXI
3918DEFHEADING()
3919
3920DEFHEADING(Generic object creation:)
3921STEXI
3922@table @option
3923ETEXI
3924
3925DEF("object", HAS_ARG, QEMU_OPTION_object,
3926    "-object TYPENAME[,PROP1=VALUE1,...]\n"
3927    "                create a new object of type TYPENAME setting properties\n"
3928    "                in the order they are specified.  Note that the 'id'\n"
3929    "                property must be set.  These objects are placed in the\n"
3930    "                '/objects' path.\n",
3931    QEMU_ARCH_ALL)
3932STEXI
3933@item -object @var{typename}[,@var{prop1}=@var{value1},...]
3934@findex -object
3935Create a new object of type @var{typename} setting properties
3936in the order they are specified.  Note that the 'id'
3937property must be set.  These objects are placed in the
3938'/objects' path.
3939
3940@table @option
3941
3942@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}
3943
3944Creates a memory file backend object, which can be used to back
3945the guest RAM with huge pages.
3946
3947The @option{id} parameter is a unique ID that will be used to reference this
3948memory region when configuring the @option{-numa} argument.
3949
3950The @option{size} option provides the size of the memory region, and accepts
3951common suffixes, eg @option{500M}.
3952
3953The @option{mem-path} provides the path to either a shared memory or huge page
3954filesystem mount.
3955
3956The @option{share} boolean option determines whether the memory
3957region is marked as private to QEMU, or shared. The latter allows
3958a co-operating external process to access the QEMU memory region.
3959
3960The @option{share} is also required for pvrdma devices due to
3961limitations in the RDMA API provided by Linux.
3962
3963Setting share=on might affect the ability to configure NUMA
3964bindings for the memory backend under some circumstances, see
3965Documentation/vm/numa_memory_policy.txt on the Linux kernel
3966source tree for additional details.
3967
3968Setting the @option{discard-data} boolean option to @var{on}
3969indicates that file contents can be destroyed when QEMU exits,
3970to avoid unnecessarily flushing data to the backing file.  Note
3971that @option{discard-data} is only an optimization, and QEMU
3972might not discard file contents if it aborts unexpectedly or is
3973terminated using SIGKILL.
3974
3975The @option{merge} boolean option enables memory merge, also known as
3976MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
3977memory deduplication.
3978
3979Setting the @option{dump} boolean option to @var{off} excludes the memory from
3980core dumps. This feature is also known as MADV_DONTDUMP.
3981
3982The @option{prealloc} boolean option enables memory preallocation.
3983
3984The @option{host-nodes} option binds the memory range to a list of NUMA host
3985nodes.
3986
3987The @option{policy} option sets the NUMA policy to one of the following values:
3988
3989@table @option
3990@item @var{default}
3991default host policy
3992
3993@item @var{preferred}
3994prefer the given host node list for allocation
3995
3996@item @var{bind}
3997restrict memory allocation to the given host node list
3998
3999@item @var{interleave}
4000interleave memory allocations across the given host node list
4001@end table
4002
4003The @option{align} option specifies the base address alignment when
4004QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4005@option{2M}. Some backend store specified by @option{mem-path}
4006requires an alignment different than the default one used by QEMU, eg
4007the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4008such cases, users can specify the required alignment via this option.
4009
4010The @option{pmem} option specifies whether the backing file specified
4011by @option{mem-path} is in host persistent memory that can be accessed
4012using the SNIA NVM programming model (e.g. Intel NVDIMM).
4013If @option{pmem} is set to 'on', QEMU will take necessary operations to
4014guarantee the persistence of its own writes to @option{mem-path}
4015(e.g. in vNVDIMM label emulation and live migration).
4016
4017@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}
4018
4019Creates a memory backend object, which can be used to back the guest RAM.
4020Memory backend objects offer more control than the @option{-m} option that is
4021traditionally used to define guest RAM. Please refer to
4022@option{memory-backend-file} for a description of the options.
4023
4024@item -object memory-backend-memfd,id=@var{id},merge=@var{on|off},dump=@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}
4025
4026Creates an anonymous memory file backend object, which allows QEMU to
4027share the memory with an external process (e.g. when using
4028vhost-user). The memory is allocated with memfd and optional
4029sealing. (Linux only)
4030
4031The @option{seal} option creates a sealed-file, that will block
4032further resizing the memory ('on' by default).
4033
4034The @option{hugetlb} option specify the file to be created resides in
4035the hugetlbfs filesystem (since Linux 4.14).  Used in conjunction with
4036the @option{hugetlb} option, the @option{hugetlbsize} option specify
4037the hugetlb page size on systems that support multiple hugetlb page
4038sizes (it must be a power of 2 value supported by the system).
4039
4040In some versions of Linux, the @option{hugetlb} option is incompatible
4041with the @option{seal} option (requires at least Linux 4.16).
4042
4043Please refer to @option{memory-backend-file} for a description of the
4044other options.
4045
4046@item -object rng-random,id=@var{id},filename=@var{/dev/random}
4047
4048Creates a random number generator backend which obtains entropy from
4049a device on the host. The @option{id} parameter is a unique ID that
4050will be used to reference this entropy backend from the @option{virtio-rng}
4051device. The @option{filename} parameter specifies which file to obtain
4052entropy from and if omitted defaults to @option{/dev/random}.
4053
4054@item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4055
4056Creates a random number generator backend which obtains entropy from
4057an external daemon running on the host. The @option{id} parameter is
4058a unique ID that will be used to reference this entropy backend from
4059the @option{virtio-rng} device. The @option{chardev} parameter is
4060the unique ID of a character device backend that provides the connection
4061to the RNG daemon.
4062
4063@item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4064
4065Creates a TLS anonymous credentials object, which can be used to provide
4066TLS support on network backends. The @option{id} parameter is a unique
4067ID which network backends will use to access the credentials. The
4068@option{endpoint} is either @option{server} or @option{client} depending
4069on whether the QEMU network backend that uses the credentials will be
4070acting as a client or as a server. If @option{verify-peer} is enabled
4071(the default) then once the handshake is completed, the peer credentials
4072will be verified, though this is a no-op for anonymous credentials.
4073
4074The @var{dir} parameter tells QEMU where to find the credential
4075files. For server endpoints, this directory may contain a file
4076@var{dh-params.pem} providing diffie-hellman parameters to use
4077for the TLS server. If the file is missing, QEMU will generate
4078a set of DH parameters at startup. This is a computationally
4079expensive operation that consumes random pool entropy, so it is
4080recommended that a persistent set of parameters be generated
4081upfront and saved.
4082
4083@item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4084
4085Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4086TLS support on network backends. The @option{id} parameter is a unique
4087ID which network backends will use to access the credentials. The
4088@option{endpoint} is either @option{server} or @option{client} depending
4089on whether the QEMU network backend that uses the credentials will be
4090acting as a client or as a server. For clients only, @option{username}
4091is the username which will be sent to the server.  If omitted
4092it defaults to ``qemu''.
4093
4094The @var{dir} parameter tells QEMU where to find the keys file.
4095It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4096pairs.  This file can most easily be created using the GnuTLS
4097@code{psktool} program.
4098
4099For server endpoints, @var{dir} may also contain a file
4100@var{dh-params.pem} providing diffie-hellman parameters to use
4101for the TLS server. If the file is missing, QEMU will generate
4102a set of DH parameters at startup. This is a computationally
4103expensive operation that consumes random pool entropy, so it is
4104recommended that a persistent set of parameters be generated
4105up front and saved.
4106
4107@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}
4108
4109Creates a TLS anonymous credentials object, which can be used to provide
4110TLS support on network backends. The @option{id} parameter is a unique
4111ID which network backends will use to access the credentials. The
4112@option{endpoint} is either @option{server} or @option{client} depending
4113on whether the QEMU network backend that uses the credentials will be
4114acting as a client or as a server. If @option{verify-peer} is enabled
4115(the default) then once the handshake is completed, the peer credentials
4116will be verified. With x509 certificates, this implies that the clients
4117must be provided with valid client certificates too.
4118
4119The @var{dir} parameter tells QEMU where to find the credential
4120files. For server endpoints, this directory may contain a file
4121@var{dh-params.pem} providing diffie-hellman parameters to use
4122for the TLS server. If the file is missing, QEMU will generate
4123a set of DH parameters at startup. This is a computationally
4124expensive operation that consumes random pool entropy, so it is
4125recommended that a persistent set of parameters be generated
4126upfront and saved.
4127
4128For x509 certificate credentials the directory will contain further files
4129providing the x509 certificates. The certificates must be stored
4130in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4131@var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4132@var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4133
4134For the @var{server-key.pem} and @var{client-key.pem} files which
4135contain sensitive private keys, it is possible to use an encrypted
4136version by providing the @var{passwordid} parameter. This provides
4137the ID of a previously created @code{secret} object containing the
4138password for decryption.
4139
4140The @var{priority} parameter allows to override the global default
4141priority used by gnutls. This can be useful if the system administrator
4142needs to use a weaker set of crypto priorities for QEMU without
4143potentially forcing the weakness onto all applications. Or conversely
4144if one wants wants a stronger default for QEMU than for all other
4145applications, they can do this through this parameter. Its format is
4146a gnutls priority string as described at
4147@url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4148
4149@item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4150
4151Interval @var{t} can't be 0, this filter batches the packet delivery: all
4152packets arriving in a given interval on netdev @var{netdevid} are delayed
4153until the end of the interval. Interval is in microseconds.
4154@option{status} is optional that indicate whether the netfilter is
4155on (enabled) or off (disabled), the default status for netfilter will be 'on'.
4156
4157queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4158
4159@option{all}: the filter is attached both to the receive and the transmit
4160              queue of the netdev (default).
4161
4162@option{rx}: the filter is attached to the receive queue of the netdev,
4163             where it will receive packets sent to the netdev.
4164
4165@option{tx}: the filter is attached to the transmit queue of the netdev,
4166             where it will receive packets sent by the netdev.
4167
4168@item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4169
4170filter-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.
4171
4172@item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4173
4174filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4175@var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag,
4176filter-redirector will redirect packet with vnet_hdr_len.
4177Create a filter-redirector we need to differ outdev id from indev id, id can not
4178be the same. we can just use indev or outdev, but at least one of indev or outdev
4179need to be specified.
4180
4181@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support]
4182
4183Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4184secondary from primary to keep secondary tcp connection,and rewrite
4185tcp packet to primary from secondary make tcp packet can be handled by
4186client.if it has the vnet_hdr_support flag, we can parse packet with vnet header.
4187
4188usage:
4189colo secondary:
4190-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4191-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4192-object filter-rewriter,id=rew0,netdev=hn0,queue=all
4193
4194@item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4195
4196Dump the network traffic on netdev @var{dev} to the file specified by
4197@var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4198The file format is libpcap, so it can be analyzed with tools such as tcpdump
4199or Wireshark.
4200
4201@item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},outdev=@var{chardevid}[,vnet_hdr_support]
4202
4203Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4204secondary packet. If the packets are same, we will output primary
4205packet to outdev@var{chardevid}, else we will notify colo-frame
4206do checkpoint and send primary packet to outdev@var{chardevid}.
4207if it has the vnet_hdr_support flag, colo compare will send/recv packet with vnet_hdr_len.
4208
4209we must use it with the help of filter-mirror and filter-redirector.
4210
4211@example
4212
4213primary:
4214-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4215-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4216-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4217-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4218-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4219-chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4220-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4221-chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4222-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4223-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4224-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4225-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
4226
4227secondary:
4228-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4229-device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4230-chardev socket,id=red0,host=3.3.3.3,port=9003
4231-chardev socket,id=red1,host=3.3.3.3,port=9004
4232-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4233-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4234
4235@end example
4236
4237If you want to know the detail of above command line, you can read
4238the colo-compare git log.
4239
4240@item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4241
4242Creates a cryptodev backend which executes crypto opreation from
4243the QEMU cipher APIS. The @var{id} parameter is
4244a unique ID that will be used to reference this cryptodev backend from
4245the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4246which specify the queue number of cryptodev backend, the default of
4247@var{queues} is 1.
4248
4249@example
4250
4251 # qemu-system-x86_64 \
4252   [...] \
4253       -object cryptodev-backend-builtin,id=cryptodev0 \
4254       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4255   [...]
4256@end example
4257
4258@item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}]
4259
4260Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}.
4261The @var{id} parameter is a unique ID that will be used to reference this
4262cryptodev backend from the @option{virtio-crypto} device.
4263The chardev should be a unix domain socket backed one. The vhost-user uses
4264a specifically defined protocol to pass vhost ioctl replacement messages
4265to an application on the other end of the socket.
4266The @var{queues} parameter is optional, which specify the queue number
4267of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1.
4268
4269@example
4270
4271 # qemu-system-x86_64 \
4272   [...] \
4273       -chardev socket,id=chardev0,path=/path/to/socket \
4274       -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \
4275       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4276   [...]
4277@end example
4278
4279@item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4280@item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4281
4282Defines a secret to store a password, encryption key, or some other sensitive
4283data. The sensitive data can either be passed directly via the @var{data}
4284parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4285parameter is insecure unless the sensitive data is encrypted.
4286
4287The sensitive data can be provided in raw format (the default), or base64.
4288When encoded as JSON, the raw format only supports valid UTF-8 characters,
4289so base64 is recommended for sending binary data. QEMU will convert from
4290which ever format is provided to the format it needs internally. eg, an
4291RBD password can be provided in raw format, even though it will be base64
4292encoded when passed onto the RBD sever.
4293
4294For added protection, it is possible to encrypt the data associated with
4295a secret using the AES-256-CBC cipher. Use of encryption is indicated
4296by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4297parameter provides the ID of a previously defined secret that contains
4298the AES-256 decryption key. This key should be 32-bytes long and be
4299base64 encoded. The @var{iv} parameter provides the random initialization
4300vector used for encryption of this particular secret and should be a
4301base64 encrypted string of the 16-byte IV.
4302
4303The simplest (insecure) usage is to provide the secret inline
4304
4305@example
4306
4307 # $QEMU -object secret,id=sec0,data=letmein,format=raw
4308
4309@end example
4310
4311The simplest secure usage is to provide the secret via a file
4312
4313 # printf "letmein" > mypasswd.txt
4314 # $QEMU -object secret,id=sec0,file=mypasswd.txt,format=raw
4315
4316For greater security, AES-256-CBC should be used. To illustrate usage,
4317consider the openssl command line tool which can encrypt the data. Note
4318that when encrypting, the plaintext must be padded to the cipher block
4319size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4320
4321First a master key needs to be created in base64 encoding:
4322
4323@example
4324 # openssl rand -base64 32 > key.b64
4325 # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
4326@end example
4327
4328Each secret to be encrypted needs to have a random initialization vector
4329generated. These do not need to be kept secret
4330
4331@example
4332 # openssl rand -base64 16 > iv.b64
4333 # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
4334@end example
4335
4336The secret to be defined can now be encrypted, in this case we're
4337telling openssl to base64 encode the result, but it could be left
4338as raw bytes if desired.
4339
4340@example
4341 # SECRET=$(printf "letmein" |
4342            openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4343@end example
4344
4345When launching QEMU, create a master secret pointing to @code{key.b64}
4346and specify that to be used to decrypt the user password. Pass the
4347contents of @code{iv.b64} to the second secret
4348
4349@example
4350 # $QEMU \
4351     -object secret,id=secmaster0,format=base64,file=key.b64 \
4352     -object secret,id=sec0,keyid=secmaster0,format=base64,\
4353         data=$SECRET,iv=$(<iv.b64)
4354@end example
4355
4356@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}]
4357
4358Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4359to provide the guest memory encryption support on AMD processors.
4360
4361When memory encryption is enabled, one of the physical address bit (aka the
4362C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4363is used to provide the C-bit position. The C-bit position is Host family dependent
4364hence user must provide this value. On EPYC, the value should be 47.
4365
4366When memory encryption is enabled, we loose certain bits in physical address space.
4367The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4368physical address space. Similar to C-bit, the value is Host family dependent.
4369On EPYC, the value should be 5.
4370
4371The @option{sev-device} provides the device file to use for communicating with
4372the SEV firmware running inside AMD Secure Processor. The default device is
4373'/dev/sev'. If hardware supports memory encryption then /dev/sev devices are
4374created by CCP driver.
4375
4376The @option{policy} provides the guest policy to be enforced by the SEV firmware
4377and restrict what configuration and operational commands can be performed on this
4378guest by the hypervisor. The policy should be provided by the guest owner and is
4379bound to the guest and cannot be changed throughout the lifetime of the guest.
4380The default is 0.
4381
4382If guest @option{policy} allows sharing the key with another SEV guest then
4383@option{handle} can be use to provide handle of the guest from which to share
4384the key.
4385
4386The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4387Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters
4388are used for establishing a cryptographic session with the guest owner to
4389negotiate keys used for attestation. The file must be encoded in base64.
4390
4391e.g to launch a SEV guest
4392@example
4393 # $QEMU \
4394     ......
4395     -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
4396     -machine ...,memory-encryption=sev0
4397     .....
4398
4399@end example
4400@end table
4401
4402ETEXI
4403
4404
4405HXCOMM This is the last statement. Insert new options before this line!
4406STEXI
4407@end table
4408ETEXI
4409