qemu/qemu-options.hx
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   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\n"
1220    "-display egl-headless[,rendernode=<file>]"
1221    "                select display type\n"
1222    "The default display is equivalent to\n"
1223#if defined(CONFIG_GTK)
1224            "\t\"-display gtk\"\n"
1225#elif defined(CONFIG_SDL)
1226            "\t\"-display sdl\"\n"
1227#elif defined(CONFIG_COCOA)
1228            "\t\"-display cocoa\"\n"
1229#elif defined(CONFIG_VNC)
1230            "\t\"-vnc localhost:0,to=99,id=default\"\n"
1231#else
1232            "\t\"-display none\"\n"
1233#endif
1234    , QEMU_ARCH_ALL)
1235STEXI
1236@item -display @var{type}
1237@findex -display
1238Select type of display to use. This option is a replacement for the
1239old style -sdl/-curses/... options. Valid values for @var{type} are
1240@table @option
1241@item sdl
1242Display video output via SDL (usually in a separate graphics
1243window; see the SDL documentation for other possibilities).
1244@item curses
1245Display video output via curses. For graphics device models which
1246support a text mode, QEMU can display this output using a
1247curses/ncurses interface. Nothing is displayed when the graphics
1248device is in graphical mode or if the graphics device does not support
1249a text mode. Generally only the VGA device models support text mode.
1250@item none
1251Do not display video output. The guest will still see an emulated
1252graphics card, but its output will not be displayed to the QEMU
1253user. This option differs from the -nographic option in that it
1254only affects what is done with video output; -nographic also changes
1255the destination of the serial and parallel port data.
1256@item gtk
1257Display video output in a GTK window. This interface provides drop-down
1258menus and other UI elements to configure and control the VM during
1259runtime.
1260@item vnc
1261Start a VNC server on display <arg>
1262@item egl-headless
1263Offload all OpenGL operations to a local DRI device. For any graphical display,
1264this display needs to be paired with either VNC or SPICE displays.
1265@end table
1266ETEXI
1267
1268DEF("nographic", 0, QEMU_OPTION_nographic,
1269    "-nographic      disable graphical output and redirect serial I/Os to console\n",
1270    QEMU_ARCH_ALL)
1271STEXI
1272@item -nographic
1273@findex -nographic
1274Normally, if QEMU is compiled with graphical window support, it displays
1275output such as guest graphics, guest console, and the QEMU monitor in a
1276window. With this option, you can totally disable graphical output so
1277that QEMU is a simple command line application. The emulated serial port
1278is redirected on the console and muxed with the monitor (unless
1279redirected elsewhere explicitly). Therefore, you can still use QEMU to
1280debug a Linux kernel with a serial console. Use @key{C-a h} for help on
1281switching between the console and monitor.
1282ETEXI
1283
1284DEF("curses", 0, QEMU_OPTION_curses,
1285    "-curses         shorthand for -display curses\n",
1286    QEMU_ARCH_ALL)
1287STEXI
1288@item -curses
1289@findex -curses
1290Normally, if QEMU is compiled with graphical window support, it displays
1291output such as guest graphics, guest console, and the QEMU monitor in a
1292window. With this option, QEMU can display the VGA output when in text
1293mode using a curses/ncurses interface. Nothing is displayed in graphical
1294mode.
1295ETEXI
1296
1297DEF("no-frame", 0, QEMU_OPTION_no_frame,
1298    "-no-frame       open SDL window without a frame and window decorations\n",
1299    QEMU_ARCH_ALL)
1300STEXI
1301@item -no-frame
1302@findex -no-frame
1303Do not use decorations for SDL windows and start them using the whole
1304available screen space. This makes the using QEMU in a dedicated desktop
1305workspace more convenient.
1306ETEXI
1307
1308DEF("alt-grab", 0, QEMU_OPTION_alt_grab,
1309    "-alt-grab       use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n",
1310    QEMU_ARCH_ALL)
1311STEXI
1312@item -alt-grab
1313@findex -alt-grab
1314Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that this also
1315affects the special keys (for fullscreen, monitor-mode switching, etc).
1316ETEXI
1317
1318DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab,
1319    "-ctrl-grab      use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n",
1320    QEMU_ARCH_ALL)
1321STEXI
1322@item -ctrl-grab
1323@findex -ctrl-grab
1324Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this also
1325affects the special keys (for fullscreen, monitor-mode switching, etc).
1326ETEXI
1327
1328DEF("no-quit", 0, QEMU_OPTION_no_quit,
1329    "-no-quit        disable SDL window close capability\n", QEMU_ARCH_ALL)
1330STEXI
1331@item -no-quit
1332@findex -no-quit
1333Disable SDL window close capability.
1334ETEXI
1335
1336DEF("sdl", 0, QEMU_OPTION_sdl,
1337    "-sdl            shorthand for -display sdl\n", QEMU_ARCH_ALL)
1338STEXI
1339@item -sdl
1340@findex -sdl
1341Enable SDL.
1342ETEXI
1343
1344DEF("spice", HAS_ARG, QEMU_OPTION_spice,
1345    "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n"
1346    "       [,x509-key-file=<file>][,x509-key-password=<file>]\n"
1347    "       [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n"
1348    "       [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n"
1349    "       [,tls-ciphers=<list>]\n"
1350    "       [,tls-channel=[main|display|cursor|inputs|record|playback]]\n"
1351    "       [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n"
1352    "       [,sasl][,password=<secret>][,disable-ticketing]\n"
1353    "       [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n"
1354    "       [,jpeg-wan-compression=[auto|never|always]]\n"
1355    "       [,zlib-glz-wan-compression=[auto|never|always]]\n"
1356    "       [,streaming-video=[off|all|filter]][,disable-copy-paste]\n"
1357    "       [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n"
1358    "       [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
1359    "       [,gl=[on|off]][,rendernode=<file>]\n"
1360    "   enable spice\n"
1361    "   at least one of {port, tls-port} is mandatory\n",
1362    QEMU_ARCH_ALL)
1363STEXI
1364@item -spice @var{option}[,@var{option}[,...]]
1365@findex -spice
1366Enable the spice remote desktop protocol. Valid options are
1367
1368@table @option
1369
1370@item port=<nr>
1371Set the TCP port spice is listening on for plaintext channels.
1372
1373@item addr=<addr>
1374Set the IP address spice is listening on.  Default is any address.
1375
1376@item ipv4
1377@itemx ipv6
1378@itemx unix
1379Force using the specified IP version.
1380
1381@item password=<secret>
1382Set the password you need to authenticate.
1383
1384@item sasl
1385Require that the client use SASL to authenticate with the spice.
1386The exact choice of authentication method used is controlled from the
1387system / user's SASL configuration file for the 'qemu' service. This
1388is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1389unprivileged user, an environment variable SASL_CONF_PATH can be used
1390to make it search alternate locations for the service config.
1391While some SASL auth methods can also provide data encryption (eg GSSAPI),
1392it is recommended that SASL always be combined with the 'tls' and
1393'x509' settings to enable use of SSL and server certificates. This
1394ensures a data encryption preventing compromise of authentication
1395credentials.
1396
1397@item disable-ticketing
1398Allow client connects without authentication.
1399
1400@item disable-copy-paste
1401Disable copy paste between the client and the guest.
1402
1403@item disable-agent-file-xfer
1404Disable spice-vdagent based file-xfer between the client and the guest.
1405
1406@item tls-port=<nr>
1407Set the TCP port spice is listening on for encrypted channels.
1408
1409@item x509-dir=<dir>
1410Set the x509 file directory. Expects same filenames as -vnc $display,x509=$dir
1411
1412@item x509-key-file=<file>
1413@itemx x509-key-password=<file>
1414@itemx x509-cert-file=<file>
1415@itemx x509-cacert-file=<file>
1416@itemx x509-dh-key-file=<file>
1417The x509 file names can also be configured individually.
1418
1419@item tls-ciphers=<list>
1420Specify which ciphers to use.
1421
1422@item tls-channel=[main|display|cursor|inputs|record|playback]
1423@itemx plaintext-channel=[main|display|cursor|inputs|record|playback]
1424Force specific channel to be used with or without TLS encryption.  The
1425options can be specified multiple times to configure multiple
1426channels.  The special name "default" can be used to set the default
1427mode.  For channels which are not explicitly forced into one mode the
1428spice client is allowed to pick tls/plaintext as he pleases.
1429
1430@item image-compression=[auto_glz|auto_lz|quic|glz|lz|off]
1431Configure image compression (lossless).
1432Default is auto_glz.
1433
1434@item jpeg-wan-compression=[auto|never|always]
1435@itemx zlib-glz-wan-compression=[auto|never|always]
1436Configure wan image compression (lossy for slow links).
1437Default is auto.
1438
1439@item streaming-video=[off|all|filter]
1440Configure video stream detection.  Default is off.
1441
1442@item agent-mouse=[on|off]
1443Enable/disable passing mouse events via vdagent.  Default is on.
1444
1445@item playback-compression=[on|off]
1446Enable/disable audio stream compression (using celt 0.5.1).  Default is on.
1447
1448@item seamless-migration=[on|off]
1449Enable/disable spice seamless migration. Default is off.
1450
1451@item gl=[on|off]
1452Enable/disable OpenGL context. Default is off.
1453
1454@item rendernode=<file>
1455DRM render node for OpenGL rendering. If not specified, it will pick
1456the first available. (Since 2.9)
1457
1458@end table
1459ETEXI
1460
1461DEF("portrait", 0, QEMU_OPTION_portrait,
1462    "-portrait       rotate graphical output 90 deg left (only PXA LCD)\n",
1463    QEMU_ARCH_ALL)
1464STEXI
1465@item -portrait
1466@findex -portrait
1467Rotate graphical output 90 deg left (only PXA LCD).
1468ETEXI
1469
1470DEF("rotate", HAS_ARG, QEMU_OPTION_rotate,
1471    "-rotate <deg>   rotate graphical output some deg left (only PXA LCD)\n",
1472    QEMU_ARCH_ALL)
1473STEXI
1474@item -rotate @var{deg}
1475@findex -rotate
1476Rotate graphical output some deg left (only PXA LCD).
1477ETEXI
1478
1479DEF("vga", HAS_ARG, QEMU_OPTION_vga,
1480    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
1481    "                select video card type\n", QEMU_ARCH_ALL)
1482STEXI
1483@item -vga @var{type}
1484@findex -vga
1485Select type of VGA card to emulate. Valid values for @var{type} are
1486@table @option
1487@item cirrus
1488Cirrus Logic GD5446 Video card. All Windows versions starting from
1489Windows 95 should recognize and use this graphic card. For optimal
1490performances, use 16 bit color depth in the guest and the host OS.
1491(This card was the default before QEMU 2.2)
1492@item std
1493Standard VGA card with Bochs VBE extensions.  If your guest OS
1494supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if you want
1495to use high resolution modes (>= 1280x1024x16) then you should use
1496this option. (This card is the default since QEMU 2.2)
1497@item vmware
1498VMWare SVGA-II compatible adapter. Use it if you have sufficiently
1499recent XFree86/XOrg server or Windows guest with a driver for this
1500card.
1501@item qxl
1502QXL paravirtual graphic card.  It is VGA compatible (including VESA
15032.0 VBE support).  Works best with qxl guest drivers installed though.
1504Recommended choice when using the spice protocol.
1505@item tcx
1506(sun4m only) Sun TCX framebuffer. This is the default framebuffer for
1507sun4m machines and offers both 8-bit and 24-bit colour depths at a
1508fixed resolution of 1024x768.
1509@item cg3
1510(sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
1511for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
1512resolutions aimed at people wishing to run older Solaris versions.
1513@item virtio
1514Virtio VGA card.
1515@item none
1516Disable VGA card.
1517@end table
1518ETEXI
1519
1520DEF("full-screen", 0, QEMU_OPTION_full_screen,
1521    "-full-screen    start in full screen\n", QEMU_ARCH_ALL)
1522STEXI
1523@item -full-screen
1524@findex -full-screen
1525Start in full screen.
1526ETEXI
1527
1528DEF("g", 1, QEMU_OPTION_g ,
1529    "-g WxH[xDEPTH]  Set the initial graphical resolution and depth\n",
1530    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
1531STEXI
1532@item -g @var{width}x@var{height}[x@var{depth}]
1533@findex -g
1534Set the initial graphical resolution and depth (PPC, SPARC only).
1535ETEXI
1536
1537DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
1538    "-vnc <display>  shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
1539STEXI
1540@item -vnc @var{display}[,@var{option}[,@var{option}[,...]]]
1541@findex -vnc
1542Normally, if QEMU is compiled with graphical window support, it displays
1543output such as guest graphics, guest console, and the QEMU monitor in a
1544window. With this option, you can have QEMU listen on VNC display
1545@var{display} and redirect the VGA display over the VNC session. It is
1546very useful to enable the usb tablet device when using this option
1547(option @option{-device usb-tablet}). When using the VNC display, you
1548must use the @option{-k} parameter to set the keyboard layout if you are
1549not using en-us. Valid syntax for the @var{display} is
1550
1551@table @option
1552
1553@item to=@var{L}
1554
1555With this option, QEMU will try next available VNC @var{display}s, until the
1556number @var{L}, if the origianlly defined "-vnc @var{display}" is not
1557available, e.g. port 5900+@var{display} is already used by another
1558application. By default, to=0.
1559
1560@item @var{host}:@var{d}
1561
1562TCP connections will only be allowed from @var{host} on display @var{d}.
1563By convention the TCP port is 5900+@var{d}. Optionally, @var{host} can
1564be omitted in which case the server will accept connections from any host.
1565
1566@item unix:@var{path}
1567
1568Connections will be allowed over UNIX domain sockets where @var{path} is the
1569location of a unix socket to listen for connections on.
1570
1571@item none
1572
1573VNC is initialized but not started. The monitor @code{change} command
1574can be used to later start the VNC server.
1575
1576@end table
1577
1578Following the @var{display} value there may be one or more @var{option} flags
1579separated by commas. Valid options are
1580
1581@table @option
1582
1583@item reverse
1584
1585Connect to a listening VNC client via a ``reverse'' connection. The
1586client is specified by the @var{display}. For reverse network
1587connections (@var{host}:@var{d},@code{reverse}), the @var{d} argument
1588is a TCP port number, not a display number.
1589
1590@item websocket
1591
1592Opens an additional TCP listening port dedicated to VNC Websocket connections.
1593If a bare @var{websocket} option is given, the Websocket port is
15945700+@var{display}. An alternative port can be specified with the
1595syntax @code{websocket}=@var{port}.
1596
1597If @var{host} is specified connections will only be allowed from this host.
1598It is possible to control the websocket listen address independently, using
1599the syntax @code{websocket}=@var{host}:@var{port}.
1600
1601If no TLS credentials are provided, the websocket connection runs in
1602unencrypted mode. If TLS credentials are provided, the websocket connection
1603requires encrypted client connections.
1604
1605@item password
1606
1607Require that password based authentication is used for client connections.
1608
1609The password must be set separately using the @code{set_password} command in
1610the @ref{pcsys_monitor}. The syntax to change your password is:
1611@code{set_password <protocol> <password>} where <protocol> could be either
1612"vnc" or "spice".
1613
1614If you would like to change <protocol> password expiration, you should use
1615@code{expire_password <protocol> <expiration-time>} where expiration time could
1616be one of the following options: now, never, +seconds or UNIX time of
1617expiration, e.g. +60 to make password expire in 60 seconds, or 1335196800
1618to make password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for this
1619date and time).
1620
1621You can also use keywords "now" or "never" for the expiration time to
1622allow <protocol> password to expire immediately or never expire.
1623
1624@item tls-creds=@var{ID}
1625
1626Provides the ID of a set of TLS credentials to use to secure the
1627VNC server. They will apply to both the normal VNC server socket
1628and the websocket socket (if enabled). Setting TLS credentials
1629will cause the VNC server socket to enable the VeNCrypt auth
1630mechanism.  The credentials should have been previously created
1631using the @option{-object tls-creds} argument.
1632
1633@item sasl
1634
1635Require that the client use SASL to authenticate with the VNC server.
1636The exact choice of authentication method used is controlled from the
1637system / user's SASL configuration file for the 'qemu' service. This
1638is typically found in /etc/sasl2/qemu.conf. If running QEMU as an
1639unprivileged user, an environment variable SASL_CONF_PATH can be used
1640to make it search alternate locations for the service config.
1641While some SASL auth methods can also provide data encryption (eg GSSAPI),
1642it is recommended that SASL always be combined with the 'tls' and
1643'x509' settings to enable use of SSL and server certificates. This
1644ensures a data encryption preventing compromise of authentication
1645credentials. See the @ref{vnc_security} section for details on using
1646SASL authentication.
1647
1648@item acl
1649
1650Turn on access control lists for checking of the x509 client certificate
1651and SASL party. For x509 certs, the ACL check is made against the
1652certificate's distinguished name. This is something that looks like
1653@code{C=GB,O=ACME,L=Boston,CN=bob}. For SASL party, the ACL check is
1654made against the username, which depending on the SASL plugin, may
1655include a realm component, eg @code{bob} or @code{bob@@EXAMPLE.COM}.
1656When the @option{acl} flag is set, the initial access list will be
1657empty, with a @code{deny} policy. Thus no one will be allowed to
1658use the VNC server until the ACLs have been loaded. This can be
1659achieved using the @code{acl} monitor command.
1660
1661@item lossy
1662
1663Enable lossy compression methods (gradient, JPEG, ...). If this
1664option is set, VNC client may receive lossy framebuffer updates
1665depending on its encoding settings. Enabling this option can save
1666a lot of bandwidth at the expense of quality.
1667
1668@item non-adaptive
1669
1670Disable adaptive encodings. Adaptive encodings are enabled by default.
1671An adaptive encoding will try to detect frequently updated screen regions,
1672and send updates in these regions using a lossy encoding (like JPEG).
1673This can be really helpful to save bandwidth when playing videos. Disabling
1674adaptive encodings restores the original static behavior of encodings
1675like Tight.
1676
1677@item share=[allow-exclusive|force-shared|ignore]
1678
1679Set display sharing policy.  'allow-exclusive' allows clients to ask
1680for exclusive access.  As suggested by the rfb spec this is
1681implemented by dropping other connections.  Connecting multiple
1682clients in parallel requires all clients asking for a shared session
1683(vncviewer: -shared switch).  This is the default.  'force-shared'
1684disables exclusive client access.  Useful for shared desktop sessions,
1685where you don't want someone forgetting specify -shared disconnect
1686everybody else.  'ignore' completely ignores the shared flag and
1687allows everybody connect unconditionally.  Doesn't conform to the rfb
1688spec but is traditional QEMU behavior.
1689
1690@item key-delay-ms
1691
1692Set keyboard delay, for key down and key up events, in milliseconds.
1693Default is 10.  Keyboards are low-bandwidth devices, so this slowdown
1694can help the device and guest to keep up and not lose events in case
1695events are arriving in bulk.  Possible causes for the latter are flaky
1696network connections, or scripts for automated testing.
1697
1698@end table
1699ETEXI
1700
1701STEXI
1702@end table
1703ETEXI
1704ARCHHEADING(, QEMU_ARCH_I386)
1705
1706ARCHHEADING(i386 target only:, QEMU_ARCH_I386)
1707STEXI
1708@table @option
1709ETEXI
1710
1711DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack,
1712    "-win2k-hack     use it when installing Windows 2000 to avoid a disk full bug\n",
1713    QEMU_ARCH_I386)
1714STEXI
1715@item -win2k-hack
1716@findex -win2k-hack
1717Use it when installing Windows 2000 to avoid a disk full bug. After
1718Windows 2000 is installed, you no longer need this option (this option
1719slows down the IDE transfers).
1720ETEXI
1721
1722DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk,
1723    "-no-fd-bootchk  disable boot signature checking for floppy disks\n",
1724    QEMU_ARCH_I386)
1725STEXI
1726@item -no-fd-bootchk
1727@findex -no-fd-bootchk
1728Disable boot signature checking for floppy disks in BIOS. May
1729be needed to boot from old floppy disks.
1730ETEXI
1731
1732DEF("no-acpi", 0, QEMU_OPTION_no_acpi,
1733           "-no-acpi        disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1734STEXI
1735@item -no-acpi
1736@findex -no-acpi
1737Disable ACPI (Advanced Configuration and Power Interface) support. Use
1738it if your guest OS complains about ACPI problems (PC target machine
1739only).
1740ETEXI
1741
1742DEF("no-hpet", 0, QEMU_OPTION_no_hpet,
1743    "-no-hpet        disable HPET\n", QEMU_ARCH_I386)
1744STEXI
1745@item -no-hpet
1746@findex -no-hpet
1747Disable HPET support.
1748ETEXI
1749
1750DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
1751    "-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"
1752    "                ACPI table description\n", QEMU_ARCH_I386)
1753STEXI
1754@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}]...]
1755@findex -acpitable
1756Add ACPI table with specified header fields and context from specified files.
1757For file=, take whole ACPI table from the specified files, including all
1758ACPI headers (possible overridden by other options).
1759For data=, only data
1760portion of the table is used, all header information is specified in the
1761command line.
1762If a SLIC table is supplied to QEMU, then the SLIC's oem_id and oem_table_id
1763fields will override the same in the RSDT and the FADT (a.k.a. FACP), in order
1764to ensure the field matches required by the Microsoft SLIC spec and the ACPI
1765spec.
1766ETEXI
1767
1768DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
1769    "-smbios file=binary\n"
1770    "                load SMBIOS entry from binary file\n"
1771    "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n"
1772    "              [,uefi=on|off]\n"
1773    "                specify SMBIOS type 0 fields\n"
1774    "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
1775    "              [,uuid=uuid][,sku=str][,family=str]\n"
1776    "                specify SMBIOS type 1 fields\n"
1777    "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n"
1778    "              [,asset=str][,location=str]\n"
1779    "                specify SMBIOS type 2 fields\n"
1780    "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n"
1781    "              [,sku=str]\n"
1782    "                specify SMBIOS type 3 fields\n"
1783    "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
1784    "              [,asset=str][,part=str]\n"
1785    "                specify SMBIOS type 4 fields\n"
1786    "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
1787    "               [,asset=str][,part=str][,speed=%d]\n"
1788    "                specify SMBIOS type 17 fields\n",
1789    QEMU_ARCH_I386 | QEMU_ARCH_ARM)
1790STEXI
1791@item -smbios file=@var{binary}
1792@findex -smbios
1793Load SMBIOS entry from binary file.
1794
1795@item -smbios type=0[,vendor=@var{str}][,version=@var{str}][,date=@var{str}][,release=@var{%d.%d}][,uefi=on|off]
1796Specify SMBIOS type 0 fields
1797
1798@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}]
1799Specify SMBIOS type 1 fields
1800
1801@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}]
1802Specify SMBIOS type 2 fields
1803
1804@item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
1805Specify SMBIOS type 3 fields
1806
1807@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
1808Specify SMBIOS type 4 fields
1809
1810@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}]
1811Specify SMBIOS type 17 fields
1812ETEXI
1813
1814STEXI
1815@end table
1816ETEXI
1817DEFHEADING()
1818
1819DEFHEADING(Network options:)
1820STEXI
1821@table @option
1822ETEXI
1823
1824DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
1825#ifdef CONFIG_SLIRP
1826    "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n"
1827    "         [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n"
1828    "         [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n"
1829    "         [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n"
1830    "         [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
1831#ifndef _WIN32
1832                                             "[,smb=dir[,smbserver=addr]]\n"
1833#endif
1834    "                configure a user mode network backend with ID 'str',\n"
1835    "                its DHCP server and optional services\n"
1836#endif
1837#ifdef _WIN32
1838    "-netdev tap,id=str,ifname=name\n"
1839    "                configure a host TAP network backend with ID 'str'\n"
1840#else
1841    "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
1842    "         [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
1843    "         [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
1844    "         [,poll-us=n]\n"
1845    "                configure a host TAP network backend with ID 'str'\n"
1846    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1847    "                use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n"
1848    "                to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
1849    "                to deconfigure it\n"
1850    "                use '[down]script=no' to disable script execution\n"
1851    "                use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n"
1852    "                configure it\n"
1853    "                use 'fd=h' to connect to an already opened TAP interface\n"
1854    "                use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n"
1855    "                use 'sndbuf=nbytes' to limit the size of the send buffer (the\n"
1856    "                default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n"
1857    "                use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n"
1858    "                use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n"
1859    "                use vhost=on to enable experimental in kernel accelerator\n"
1860    "                    (only has effect for virtio guests which use MSIX)\n"
1861    "                use vhostforce=on to force vhost on for non-MSIX virtio guests\n"
1862    "                use 'vhostfd=h' to connect to an already opened vhost net device\n"
1863    "                use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n"
1864    "                use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n"
1865    "                use 'poll-us=n' to speciy the maximum number of microseconds that could be\n"
1866    "                spent on busy polling for vhost net\n"
1867    "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
1868    "                configure a host TAP network backend with ID 'str' that is\n"
1869    "                connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n"
1870    "                using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n"
1871#endif
1872#ifdef __linux__
1873    "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n"
1874    "         [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n"
1875    "         [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n"
1876    "         [,rxcookie=rxcookie][,offset=offset]\n"
1877    "                configure a network backend with ID 'str' connected to\n"
1878    "                an Ethernet over L2TPv3 pseudowire.\n"
1879    "                Linux kernel 3.3+ as well as most routers can talk\n"
1880    "                L2TPv3. This transport allows connecting a VM to a VM,\n"
1881    "                VM to a router and even VM to Host. It is a nearly-universal\n"
1882    "                standard (RFC3391). Note - this implementation uses static\n"
1883    "                pre-configured tunnels (same as the Linux kernel).\n"
1884    "                use 'src=' to specify source address\n"
1885    "                use 'dst=' to specify destination address\n"
1886    "                use 'udp=on' to specify udp encapsulation\n"
1887    "                use 'srcport=' to specify source udp port\n"
1888    "                use 'dstport=' to specify destination udp port\n"
1889    "                use 'ipv6=on' to force v6\n"
1890    "                L2TPv3 uses cookies to prevent misconfiguration as\n"
1891    "                well as a weak security measure\n"
1892    "                use 'rxcookie=0x012345678' to specify a rxcookie\n"
1893    "                use 'txcookie=0x012345678' to specify a txcookie\n"
1894    "                use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n"
1895    "                use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n"
1896    "                use 'pincounter=on' to work around broken counter handling in peer\n"
1897    "                use 'offset=X' to add an extra offset between header and data\n"
1898#endif
1899    "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n"
1900    "                configure a network backend to connect to another network\n"
1901    "                using a socket connection\n"
1902    "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
1903    "                configure a network backend to connect to a multicast maddr and port\n"
1904    "                use 'localaddr=addr' to specify the host address to send packets from\n"
1905    "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n"
1906    "                configure a network backend to connect to another network\n"
1907    "                using an UDP tunnel\n"
1908#ifdef CONFIG_VDE
1909    "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
1910    "                configure a network backend to connect to port 'n' of a vde switch\n"
1911    "                running on host and listening for incoming connections on 'socketpath'.\n"
1912    "                Use group 'groupname' and mode 'octalmode' to change default\n"
1913    "                ownership and permissions for communication port.\n"
1914#endif
1915#ifdef CONFIG_NETMAP
1916    "-netdev netmap,id=str,ifname=name[,devname=nmname]\n"
1917    "                attach to the existing netmap-enabled network interface 'name', or to a\n"
1918    "                VALE port (created on the fly) called 'name' ('nmname' is name of the \n"
1919    "                netmap device, defaults to '/dev/netmap')\n"
1920#endif
1921#ifdef CONFIG_POSIX
1922    "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n"
1923    "                configure a vhost-user network, backed by a chardev 'dev'\n"
1924#endif
1925    "-netdev hubport,id=str,hubid=n[,netdev=nd]\n"
1926    "                configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL)
1927DEF("nic", HAS_ARG, QEMU_OPTION_nic,
1928    "-nic [tap|bridge|"
1929#ifdef CONFIG_SLIRP
1930    "user|"
1931#endif
1932#ifdef __linux__
1933    "l2tpv3|"
1934#endif
1935#ifdef CONFIG_VDE
1936    "vde|"
1937#endif
1938#ifdef CONFIG_NETMAP
1939    "netmap|"
1940#endif
1941#ifdef CONFIG_POSIX
1942    "vhost-user|"
1943#endif
1944    "socket][,option][,...][mac=macaddr]\n"
1945    "                initialize an on-board / default host NIC (using MAC address\n"
1946    "                macaddr) and connect it to the given host network backend\n"
1947    "-nic none       use it alone to have zero network devices (the default is to\n"
1948    "                provided a 'user' network connection)\n",
1949    QEMU_ARCH_ALL)
1950DEF("net", HAS_ARG, QEMU_OPTION_net,
1951    "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
1952    "                configure or create an on-board (or machine default) NIC and\n"
1953    "                connect it to hub 0 (please use -nic unless you need a hub)\n"
1954    "-net ["
1955#ifdef CONFIG_SLIRP
1956    "user|"
1957#endif
1958    "tap|"
1959    "bridge|"
1960#ifdef CONFIG_VDE
1961    "vde|"
1962#endif
1963#ifdef CONFIG_NETMAP
1964    "netmap|"
1965#endif
1966    "socket][,option][,option][,...]\n"
1967    "                old way to initialize a host network interface\n"
1968    "                (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL)
1969STEXI
1970@item -nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]
1971@findex -nic
1972This option is a shortcut for configuring both the on-board (default) guest
1973NIC hardware and the host network backend in one go. The host backend options
1974are the same as with the corresponding @option{-netdev} options below.
1975The guest NIC model can be set with @option{model=@var{modelname}}.
1976Use @option{model=help} to list the available device types.
1977The hardware MAC address can be set with @option{mac=@var{macaddr}}.
1978
1979The following two example do exactly the same, to show how @option{-nic} can
1980be used to shorten the command line length (note that the e1000 is the default
1981on i386, so the @option{model=e1000} parameter could even be omitted here, too):
1982@example
1983qemu-system-i386 -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
1984qemu-system-i386 -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
1985@end example
1986
1987@item -nic none
1988Indicate that no network devices should be configured. It is used to override
1989the default configuration (default NIC with ``user'' host network backend)
1990which is activated if no other networking options are provided.
1991
1992@item -netdev user,id=@var{id}[,@var{option}][,@var{option}][,...]
1993@findex -netdev
1994Configure user mode host network backend which requires no administrator
1995privilege to run. Valid options are:
1996
1997@table @option
1998@item id=@var{id}
1999Assign symbolic name for use in monitor commands.
2000
2001@item ipv4=on|off and ipv6=on|off
2002Specify that either IPv4 or IPv6 must be enabled. If neither is specified
2003both protocols are enabled.
2004
2005@item net=@var{addr}[/@var{mask}]
2006Set IP network address the guest will see. Optionally specify the netmask,
2007either in the form a.b.c.d or as number of valid top-most bits. Default is
200810.0.2.0/24.
2009
2010@item host=@var{addr}
2011Specify the guest-visible address of the host. Default is the 2nd IP in the
2012guest network, i.e. x.x.x.2.
2013
2014@item ipv6-net=@var{addr}[/@var{int}]
2015Set IPv6 network address the guest will see (default is fec0::/64). The
2016network prefix is given in the usual hexadecimal IPv6 address
2017notation. The prefix size is optional, and is given as the number of
2018valid top-most bits (default is 64).
2019
2020@item ipv6-host=@var{addr}
2021Specify the guest-visible IPv6 address of the host. Default is the 2nd IPv6 in
2022the guest network, i.e. xxxx::2.
2023
2024@item restrict=on|off
2025If this option is enabled, the guest will be isolated, i.e. it will not be
2026able to contact the host and no guest IP packets will be routed over the host
2027to the outside. This option does not affect any explicitly set forwarding rules.
2028
2029@item hostname=@var{name}
2030Specifies the client hostname reported by the built-in DHCP server.
2031
2032@item dhcpstart=@var{addr}
2033Specify the first of the 16 IPs the built-in DHCP server can assign. Default
2034is the 15th to 31st IP in the guest network, i.e. x.x.x.15 to x.x.x.31.
2035
2036@item dns=@var{addr}
2037Specify the guest-visible address of the virtual nameserver. The address must
2038be different from the host address. Default is the 3rd IP in the guest network,
2039i.e. x.x.x.3.
2040
2041@item ipv6-dns=@var{addr}
2042Specify the guest-visible address of the IPv6 virtual nameserver. The address
2043must be different from the host address. Default is the 3rd IP in the guest
2044network, i.e. xxxx::3.
2045
2046@item dnssearch=@var{domain}
2047Provides an entry for the domain-search list sent by the built-in
2048DHCP server. More than one domain suffix can be transmitted by specifying
2049this option multiple times. If supported, this will cause the guest to
2050automatically try to append the given domain suffix(es) in case a domain name
2051can not be resolved.
2052
2053Example:
2054@example
2055qemu-system-i386 -nic user,dnssearch=mgmt.example.org,dnssearch=example.org
2056@end example
2057
2058@item domainname=@var{domain}
2059Specifies the client domain name reported by the built-in DHCP server.
2060
2061@item tftp=@var{dir}
2062When using the user mode network stack, activate a built-in TFTP
2063server. The files in @var{dir} will be exposed as the root of a TFTP server.
2064The TFTP client on the guest must be configured in binary mode (use the command
2065@code{bin} of the Unix TFTP client).
2066
2067@item tftp-server-name=@var{name}
2068In BOOTP reply, broadcast @var{name} as the "TFTP server name" (RFC2132 option
206966). This can be used to advise the guest to load boot files or configurations
2070from a different server than the host address.
2071
2072@item bootfile=@var{file}
2073When using the user mode network stack, broadcast @var{file} as the BOOTP
2074filename. In conjunction with @option{tftp}, this can be used to network boot
2075a guest from a local directory.
2076
2077Example (using pxelinux):
2078@example
2079qemu-system-i386 -hda linux.img -boot n -device e1000,netdev=n1 \
2080    -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0
2081@end example
2082
2083@item smb=@var{dir}[,smbserver=@var{addr}]
2084When using the user mode network stack, activate a built-in SMB
2085server so that Windows OSes can access to the host files in @file{@var{dir}}
2086transparently. The IP address of the SMB server can be set to @var{addr}. By
2087default the 4th IP in the guest network is used, i.e. x.x.x.4.
2088
2089In the guest Windows OS, the line:
2090@example
209110.0.2.4 smbserver
2092@end example
2093must be added in the file @file{C:\WINDOWS\LMHOSTS} (for windows 9x/Me)
2094or @file{C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS} (Windows NT/2000).
2095
2096Then @file{@var{dir}} can be accessed in @file{\\smbserver\qemu}.
2097
2098Note that a SAMBA server must be installed on the host OS.
2099
2100@item hostfwd=[tcp|udp]:[@var{hostaddr}]:@var{hostport}-[@var{guestaddr}]:@var{guestport}
2101Redirect incoming TCP or UDP connections to the host port @var{hostport} to
2102the guest IP address @var{guestaddr} on guest port @var{guestport}. If
2103@var{guestaddr} is not specified, its value is x.x.x.15 (default first address
2104given by the built-in DHCP server). By specifying @var{hostaddr}, the rule can
2105be bound to a specific host interface. If no connection type is set, TCP is
2106used. This option can be given multiple times.
2107
2108For example, to redirect host X11 connection from screen 1 to guest
2109screen 0, use the following:
2110
2111@example
2112# on the host
2113qemu-system-i386 -nic user,hostfwd=tcp:127.0.0.1:6001-:6000
2114# this host xterm should open in the guest X11 server
2115xterm -display :1
2116@end example
2117
2118To redirect telnet connections from host port 5555 to telnet port on
2119the guest, use the following:
2120
2121@example
2122# on the host
2123qemu-system-i386 -nic user,hostfwd=tcp::5555-:23
2124telnet localhost 5555
2125@end example
2126
2127Then when you use on the host @code{telnet localhost 5555}, you
2128connect to the guest telnet server.
2129
2130@item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev}
2131@itemx guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command}
2132Forward guest TCP connections to the IP address @var{server} on port @var{port}
2133to the character device @var{dev} or to a program executed by @var{cmd:command}
2134which gets spawned for each connection. This option can be given multiple times.
2135
2136You can either use a chardev directly and have that one used throughout QEMU's
2137lifetime, like in the following example:
2138
2139@example
2140# open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever
2141# the guest accesses it
2142qemu-system-i386 -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321
2143@end example
2144
2145Or you can execute a command on every TCP connection established by the guest,
2146so that QEMU behaves similar to an inetd process for that virtual server:
2147
2148@example
2149# call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234
2150# and connect the TCP stream to its stdin/stdout
2151qemu-system-i386 -nic  'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321'
2152@end example
2153
2154@end table
2155
2156@item -netdev tap,id=@var{id}[,fd=@var{h}][,ifname=@var{name}][,script=@var{file}][,downscript=@var{dfile}][,br=@var{bridge}][,helper=@var{helper}]
2157Configure a host TAP network backend with ID @var{id}.
2158
2159Use the network script @var{file} to configure it and the network script
2160@var{dfile} to deconfigure it. If @var{name} is not provided, the OS
2161automatically provides one. The default network configure script is
2162@file{/etc/qemu-ifup} and the default network deconfigure script is
2163@file{/etc/qemu-ifdown}. Use @option{script=no} or @option{downscript=no}
2164to disable script execution.
2165
2166If running QEMU as an unprivileged user, use the network helper
2167@var{helper} to configure the TAP interface and attach it to the bridge.
2168The default network helper executable is @file{/path/to/qemu-bridge-helper}
2169and the default bridge device is @file{br0}.
2170
2171@option{fd}=@var{h} can be used to specify the handle of an already
2172opened host TAP interface.
2173
2174Examples:
2175
2176@example
2177#launch a QEMU instance with the default network script
2178qemu-system-i386 linux.img -nic tap
2179@end example
2180
2181@example
2182#launch a QEMU instance with two NICs, each one connected
2183#to a TAP device
2184qemu-system-i386 linux.img \
2185        -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \
2186        -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1
2187@end example
2188
2189@example
2190#launch a QEMU instance with the default network helper to
2191#connect a TAP device to bridge br0
2192qemu-system-i386 linux.img -device virtio-net-pci,netdev=n1 \
2193        -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper"
2194@end example
2195
2196@item -netdev bridge,id=@var{id}[,br=@var{bridge}][,helper=@var{helper}]
2197Connect a host TAP network interface to a host bridge device.
2198
2199Use the network helper @var{helper} to configure the TAP interface and
2200attach it to the bridge. The default network helper executable is
2201@file{/path/to/qemu-bridge-helper} and the default bridge
2202device is @file{br0}.
2203
2204Examples:
2205
2206@example
2207#launch a QEMU instance with the default network helper to
2208#connect a TAP device to bridge br0
2209qemu-system-i386 linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1
2210@end example
2211
2212@example
2213#launch a QEMU instance with the default network helper to
2214#connect a TAP device to bridge qemubr0
2215qemu-system-i386 linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1
2216@end example
2217
2218@item -netdev socket,id=@var{id}[,fd=@var{h}][,listen=[@var{host}]:@var{port}][,connect=@var{host}:@var{port}]
2219
2220This host network backend can be used to connect the guest's network to
2221another QEMU virtual machine using a TCP socket connection. If @option{listen}
2222is specified, QEMU waits for incoming connections on @var{port}
2223(@var{host} is optional). @option{connect} is used to connect to
2224another QEMU instance using the @option{listen} option. @option{fd}=@var{h}
2225specifies an already opened TCP socket.
2226
2227Example:
2228@example
2229# launch a first QEMU instance
2230qemu-system-i386 linux.img \
2231                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2232                 -netdev socket,id=n1,listen=:1234
2233# connect the network of this instance to the network of the first instance
2234qemu-system-i386 linux.img \
2235                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2236                 -netdev socket,id=n2,connect=127.0.0.1:1234
2237@end example
2238
2239@item -netdev socket,id=@var{id}[,fd=@var{h}][,mcast=@var{maddr}:@var{port}[,localaddr=@var{addr}]]
2240
2241Configure a socket host network backend to share the guest's network traffic
2242with another QEMU virtual machines using a UDP multicast socket, effectively
2243making a bus for every QEMU with same multicast address @var{maddr} and @var{port}.
2244NOTES:
2245@enumerate
2246@item
2247Several QEMU can be running on different hosts and share same bus (assuming
2248correct multicast setup for these hosts).
2249@item
2250mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
2251@url{http://user-mode-linux.sf.net}.
2252@item
2253Use @option{fd=h} to specify an already opened UDP multicast socket.
2254@end enumerate
2255
2256Example:
2257@example
2258# launch one QEMU instance
2259qemu-system-i386 linux.img \
2260                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2261                 -netdev socket,id=n1,mcast=230.0.0.1:1234
2262# launch another QEMU instance on same "bus"
2263qemu-system-i386 linux.img \
2264                 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \
2265                 -netdev socket,id=n2,mcast=230.0.0.1:1234
2266# launch yet another QEMU instance on same "bus"
2267qemu-system-i386 linux.img \
2268                 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \
2269                 -netdev socket,id=n3,mcast=230.0.0.1:1234
2270@end example
2271
2272Example (User Mode Linux compat.):
2273@example
2274# launch QEMU instance (note mcast address selected is UML's default)
2275qemu-system-i386 linux.img \
2276                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2277                 -netdev socket,id=n1,mcast=239.192.168.1:1102
2278# launch UML
2279/path/to/linux ubd0=/path/to/root_fs eth0=mcast
2280@end example
2281
2282Example (send packets from host's 1.2.3.4):
2283@example
2284qemu-system-i386 linux.img \
2285                 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \
2286                 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
2287@end example
2288
2289@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}]
2290Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3391) is a
2291popular protocol to transport Ethernet (and other Layer 2) data frames between
2292two systems. It is present in routers, firewalls and the Linux kernel
2293(from version 3.3 onwards).
2294
2295This transport allows a VM to communicate to another VM, router or firewall directly.
2296
2297@table @option
2298@item src=@var{srcaddr}
2299    source address (mandatory)
2300@item dst=@var{dstaddr}
2301    destination address (mandatory)
2302@item udp
2303    select udp encapsulation (default is ip).
2304@item srcport=@var{srcport}
2305    source udp port.
2306@item dstport=@var{dstport}
2307    destination udp port.
2308@item ipv6
2309    force v6, otherwise defaults to v4.
2310@item rxcookie=@var{rxcookie}
2311@itemx txcookie=@var{txcookie}
2312    Cookies are a weak form of security in the l2tpv3 specification.
2313Their function is mostly to prevent misconfiguration. By default they are 32
2314bit.
2315@item cookie64
2316    Set cookie size to 64 bit instead of the default 32
2317@item counter=off
2318    Force a 'cut-down' L2TPv3 with no counter as in
2319draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00
2320@item pincounter=on
2321    Work around broken counter handling in peer. This may also help on
2322networks which have packet reorder.
2323@item offset=@var{offset}
2324    Add an extra offset between header and data
2325@end table
2326
2327For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to the bridge br-lan
2328on the remote Linux host 1.2.3.4:
2329@example
2330# Setup tunnel on linux host using raw ip as encapsulation
2331# on 1.2.3.4
2332ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \
2333    encap udp udp_sport 16384 udp_dport 16384
2334ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \
2335    0xFFFFFFFF peer_session_id 0xFFFFFFFF
2336ifconfig vmtunnel0 mtu 1500
2337ifconfig vmtunnel0 up
2338brctl addif br-lan vmtunnel0
2339
2340
2341# on 4.3.2.1
2342# launch QEMU instance - if your network has reorder or is very lossy add ,pincounter
2343
2344qemu-system-i386 linux.img -device e1000,netdev=n1 \
2345    -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter
2346
2347@end example
2348
2349@item -netdev vde,id=@var{id}[,sock=@var{socketpath}][,port=@var{n}][,group=@var{groupname}][,mode=@var{octalmode}]
2350Configure VDE backend to connect to PORT @var{n} of a vde switch running on host and
2351listening for incoming connections on @var{socketpath}. Use GROUP @var{groupname}
2352and MODE @var{octalmode} to change default ownership and permissions for
2353communication port. This option is only available if QEMU has been compiled
2354with vde support enabled.
2355
2356Example:
2357@example
2358# launch vde switch
2359vde_switch -F -sock /tmp/myswitch
2360# launch QEMU instance
2361qemu-system-i386 linux.img -nic vde,sock=/tmp/myswitch
2362@end example
2363
2364@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
2365
2366Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
2367be a unix domain socket backed one. The vhost-user uses a specifically defined
2368protocol to pass vhost ioctl replacement messages to an application on the other
2369end of the socket. On non-MSIX guests, the feature can be forced with
2370@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
2371be created for multiqueue vhost-user.
2372
2373Example:
2374@example
2375qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
2376     -numa node,memdev=mem \
2377     -chardev socket,id=chr0,path=/path/to/socket \
2378     -netdev type=vhost-user,id=net0,chardev=chr0 \
2379     -device virtio-net-pci,netdev=net0
2380@end example
2381
2382@item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}]
2383
2384Create a hub port on the emulated hub with ID @var{hubid}.
2385
2386The hubport netdev lets you connect a NIC to a QEMU emulated hub instead of a
2387single netdev. Alternatively, you can also connect the hubport to another
2388netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option.
2389
2390@item -net nic[,netdev=@var{nd}][,macaddr=@var{mac}][,model=@var{type}] [,name=@var{name}][,addr=@var{addr}][,vectors=@var{v}]
2391@findex -net
2392Legacy option to configure or create an on-board (or machine default) Network
2393Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e.
2394the default hub), or to the netdev @var{nd}.
2395The NIC is an e1000 by default on the PC target. Optionally, the MAC address
2396can be changed to @var{mac}, the device address set to @var{addr} (PCI cards
2397only), and a @var{name} can be assigned for use in monitor commands.
2398Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
2399that the card should have; this option currently only affects virtio cards; set
2400@var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
2401NIC is created.  QEMU can emulate several different models of network card.
2402Use @code{-net nic,model=help} for a list of available devices for your target.
2403
2404@item -net user|tap|bridge|socket|l2tpv3|vde[,...][,name=@var{name}]
2405Configure a host network backend (with the options corresponding to the same
2406@option{-netdev} option) and connect it to the emulated hub 0 (the default
2407hub). Use @var{name} to specify the name of the hub port.
2408ETEXI
2409
2410STEXI
2411@end table
2412ETEXI
2413DEFHEADING()
2414
2415DEFHEADING(Character device options:)
2416
2417DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
2418    "-chardev help\n"
2419    "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2420    "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
2421    "         [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
2422    "         [,logfile=PATH][,logappend=on|off][,tls-creds=ID] (tcp)\n"
2423    "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n"
2424    "         [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)\n"
2425    "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
2426    "         [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
2427    "         [,logfile=PATH][,logappend=on|off]\n"
2428    "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2429    "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
2430    "         [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2431    "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
2432    "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2433    "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2434#ifdef _WIN32
2435    "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2436    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2437#else
2438    "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2439    "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
2440#endif
2441#ifdef CONFIG_BRLAPI
2442    "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2443#endif
2444#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
2445        || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
2446    "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2447    "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2448#endif
2449#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
2450    "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2451    "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
2452#endif
2453#if defined(CONFIG_SPICE)
2454    "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2455    "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
2456#endif
2457    , QEMU_ARCH_ALL
2458)
2459
2460STEXI
2461
2462The general form of a character device option is:
2463@table @option
2464@item -chardev @var{backend},id=@var{id}[,mux=on|off][,@var{options}]
2465@findex -chardev
2466Backend is one of:
2467@option{null},
2468@option{socket},
2469@option{udp},
2470@option{msmouse},
2471@option{vc},
2472@option{ringbuf},
2473@option{file},
2474@option{pipe},
2475@option{console},
2476@option{serial},
2477@option{pty},
2478@option{stdio},
2479@option{braille},
2480@option{tty},
2481@option{parallel},
2482@option{parport},
2483@option{spicevmc},
2484@option{spiceport}.
2485The specific backend will determine the applicable options.
2486
2487Use @code{-chardev help} to print all available chardev backend types.
2488
2489All devices must have an id, which can be any string up to 127 characters long.
2490It is used to uniquely identify this device in other command line directives.
2491
2492A character device may be used in multiplexing mode by multiple front-ends.
2493Specify @option{mux=on} to enable this mode.
2494A multiplexer is a "1:N" device, and here the "1" end is your specified chardev
2495backend, and the "N" end is the various parts of QEMU that can talk to a chardev.
2496If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will
2497create a multiplexer with your specified ID, and you can then configure multiple
2498front ends to use that chardev ID for their input/output. Up to four different
2499front ends can be connected to a single multiplexed chardev. (Without
2500multiplexing enabled, a chardev can only be used by a single front end.)
2501For instance you could use this to allow a single stdio chardev to be used by
2502two serial ports and the QEMU monitor:
2503
2504@example
2505-chardev stdio,mux=on,id=char0 \
2506-mon chardev=char0,mode=readline \
2507-serial chardev:char0 \
2508-serial chardev:char0
2509@end example
2510
2511You can have more than one multiplexer in a system configuration; for instance
2512you could have a TCP port multiplexed between UART 0 and UART 1, and stdio
2513multiplexed between the QEMU monitor and a parallel port:
2514
2515@example
2516-chardev stdio,mux=on,id=char0 \
2517-mon chardev=char0,mode=readline \
2518-parallel chardev:char0 \
2519-chardev tcp,...,mux=on,id=char1 \
2520-serial chardev:char1 \
2521-serial chardev:char1
2522@end example
2523
2524When you're using a multiplexed character device, some escape sequences are
2525interpreted in the input. @xref{mux_keys, Keys in the character backend
2526multiplexer}.
2527
2528Note that some other command line options may implicitly create multiplexed
2529character backends; for instance @option{-serial mon:stdio} creates a
2530multiplexed stdio backend connected to the serial port and the QEMU monitor,
2531and @option{-nographic} also multiplexes the console and the monitor to
2532stdio.
2533
2534There is currently no support for multiplexing in the other direction
2535(where a single QEMU front end takes input and output from multiple chardevs).
2536
2537Every backend supports the @option{logfile} option, which supplies the path
2538to a file to record all data transmitted via the backend. The @option{logappend}
2539option controls whether the log file will be truncated or appended to when
2540opened.
2541
2542@end table
2543
2544The available backends are:
2545
2546@table @option
2547@item -chardev null,id=@var{id}
2548A void device. This device will not emit any data, and will drop any data it
2549receives. The null backend does not take any options.
2550
2551@item -chardev socket,id=@var{id}[,@var{TCP options} or @var{unix options}][,server][,nowait][,telnet][,websocket][,reconnect=@var{seconds}][,tls-creds=@var{id}]
2552
2553Create a two-way stream socket, which can be either a TCP or a unix socket. A
2554unix socket will be created if @option{path} is specified. Behaviour is
2555undefined if TCP options are specified for a unix socket.
2556
2557@option{server} specifies that the socket shall be a listening socket.
2558
2559@option{nowait} specifies that QEMU should not block waiting for a client to
2560connect to a listening socket.
2561
2562@option{telnet} specifies that traffic on the socket should interpret telnet
2563escape sequences.
2564
2565@option{websocket} specifies that the socket uses WebSocket protocol for
2566communication.
2567
2568@option{reconnect} sets the timeout for reconnecting on non-server sockets when
2569the remote end goes away.  qemu will delay this many seconds and then attempt
2570to reconnect.  Zero disables reconnecting, and is the default.
2571
2572@option{tls-creds} requests enablement of the TLS protocol for encryption,
2573and specifies the id of the TLS credentials to use for the handshake. The
2574credentials must be previously created with the @option{-object tls-creds}
2575argument.
2576
2577TCP and unix socket options are given below:
2578
2579@table @option
2580
2581@item TCP options: port=@var{port}[,host=@var{host}][,to=@var{to}][,ipv4][,ipv6][,nodelay]
2582
2583@option{host} for a listening socket specifies the local address to be bound.
2584For a connecting socket species the remote host to connect to. @option{host} is
2585optional for listening sockets. If not specified it defaults to @code{0.0.0.0}.
2586
2587@option{port} for a listening socket specifies the local port to be bound. For a
2588connecting socket specifies the port on the remote host to connect to.
2589@option{port} can be given as either a port number or a service name.
2590@option{port} is required.
2591
2592@option{to} is only relevant to listening sockets. If it is specified, and
2593@option{port} cannot be bound, QEMU will attempt to bind to subsequent ports up
2594to and including @option{to} until it succeeds. @option{to} must be specified
2595as a port number.
2596
2597@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2598If neither is specified the socket may use either protocol.
2599
2600@option{nodelay} disables the Nagle algorithm.
2601
2602@item unix options: path=@var{path}
2603
2604@option{path} specifies the local path of the unix socket. @option{path} is
2605required.
2606
2607@end table
2608
2609@item -chardev udp,id=@var{id}[,host=@var{host}],port=@var{port}[,localaddr=@var{localaddr}][,localport=@var{localport}][,ipv4][,ipv6]
2610
2611Sends all traffic from the guest to a remote host over UDP.
2612
2613@option{host} specifies the remote host to connect to. If not specified it
2614defaults to @code{localhost}.
2615
2616@option{port} specifies the port on the remote host to connect to. @option{port}
2617is required.
2618
2619@option{localaddr} specifies the local address to bind to. If not specified it
2620defaults to @code{0.0.0.0}.
2621
2622@option{localport} specifies the local port to bind to. If not specified any
2623available local port will be used.
2624
2625@option{ipv4} and @option{ipv6} specify that either IPv4 or IPv6 must be used.
2626If neither is specified the device may use either protocol.
2627
2628@item -chardev msmouse,id=@var{id}
2629
2630Forward QEMU's emulated msmouse events to the guest. @option{msmouse} does not
2631take any options.
2632
2633@item -chardev vc,id=@var{id}[[,width=@var{width}][,height=@var{height}]][[,cols=@var{cols}][,rows=@var{rows}]]
2634
2635Connect to a QEMU text console. @option{vc} may optionally be given a specific
2636size.
2637
2638@option{width} and @option{height} specify the width and height respectively of
2639the console, in pixels.
2640
2641@option{cols} and @option{rows} specify that the console be sized to fit a text
2642console with the given dimensions.
2643
2644@item -chardev ringbuf,id=@var{id}[,size=@var{size}]
2645
2646Create a ring buffer with fixed size @option{size}.
2647@var{size} must be a power of two and defaults to @code{64K}.
2648
2649@item -chardev file,id=@var{id},path=@var{path}
2650
2651Log all traffic received from the guest to a file.
2652
2653@option{path} specifies the path of the file to be opened. This file will be
2654created if it does not already exist, and overwritten if it does. @option{path}
2655is required.
2656
2657@item -chardev pipe,id=@var{id},path=@var{path}
2658
2659Create a two-way connection to the guest. The behaviour differs slightly between
2660Windows hosts and other hosts:
2661
2662On Windows, a single duplex pipe will be created at
2663@file{\\.pipe\@option{path}}.
2664
2665On other hosts, 2 pipes will be created called @file{@option{path}.in} and
2666@file{@option{path}.out}. Data written to @file{@option{path}.in} will be
2667received by the guest. Data written by the guest can be read from
2668@file{@option{path}.out}. QEMU will not create these fifos, and requires them to
2669be present.
2670
2671@option{path} forms part of the pipe path as described above. @option{path} is
2672required.
2673
2674@item -chardev console,id=@var{id}
2675
2676Send traffic from the guest to QEMU's standard output. @option{console} does not
2677take any options.
2678
2679@option{console} is only available on Windows hosts.
2680
2681@item -chardev serial,id=@var{id},path=@option{path}
2682
2683Send traffic from the guest to a serial device on the host.
2684
2685On Unix hosts serial will actually accept any tty device,
2686not only serial lines.
2687
2688@option{path} specifies the name of the serial device to open.
2689
2690@item -chardev pty,id=@var{id}
2691
2692Create a new pseudo-terminal on the host and connect to it. @option{pty} does
2693not take any options.
2694
2695@option{pty} is not available on Windows hosts.
2696
2697@item -chardev stdio,id=@var{id}[,signal=on|off]
2698Connect to standard input and standard output of the QEMU process.
2699
2700@option{signal} controls if signals are enabled on the terminal, that includes
2701exiting QEMU with the key sequence @key{Control-c}. This option is enabled by
2702default, use @option{signal=off} to disable it.
2703
2704@item -chardev braille,id=@var{id}
2705
2706Connect to a local BrlAPI server. @option{braille} does not take any options.
2707
2708@item -chardev tty,id=@var{id},path=@var{path}
2709
2710@option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
2711DragonFlyBSD hosts.  It is an alias for @option{serial}.
2712
2713@option{path} specifies the path to the tty. @option{path} is required.
2714
2715@item -chardev parallel,id=@var{id},path=@var{path}
2716@itemx -chardev parport,id=@var{id},path=@var{path}
2717
2718@option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
2719
2720Connect to a local parallel port.
2721
2722@option{path} specifies the path to the parallel port device. @option{path} is
2723required.
2724
2725@item -chardev spicevmc,id=@var{id},debug=@var{debug},name=@var{name}
2726
2727@option{spicevmc} is only available when spice support is built in.
2728
2729@option{debug} debug level for spicevmc
2730
2731@option{name} name of spice channel to connect to
2732
2733Connect to a spice virtual machine channel, such as vdiport.
2734
2735@item -chardev spiceport,id=@var{id},debug=@var{debug},name=@var{name}
2736
2737@option{spiceport} is only available when spice support is built in.
2738
2739@option{debug} debug level for spicevmc
2740
2741@option{name} name of spice port to connect to
2742
2743Connect to a spice port, allowing a Spice client to handle the traffic
2744identified by a name (preferably a fqdn).
2745ETEXI
2746
2747STEXI
2748@end table
2749ETEXI
2750DEFHEADING()
2751
2752DEFHEADING(Bluetooth(R) options:)
2753STEXI
2754@table @option
2755ETEXI
2756
2757DEF("bt", HAS_ARG, QEMU_OPTION_bt, \
2758    "-bt hci,null    dumb bluetooth HCI - doesn't respond to commands\n" \
2759    "-bt hci,host[:id]\n" \
2760    "                use host's HCI with the given name\n" \
2761    "-bt hci[,vlan=n]\n" \
2762    "                emulate a standard HCI in virtual scatternet 'n'\n" \
2763    "-bt vhci[,vlan=n]\n" \
2764    "                add host computer to virtual scatternet 'n' using VHCI\n" \
2765    "-bt device:dev[,vlan=n]\n" \
2766    "                emulate a bluetooth device 'dev' in scatternet 'n'\n",
2767    QEMU_ARCH_ALL)
2768STEXI
2769@item -bt hci[...]
2770@findex -bt
2771Defines the function of the corresponding Bluetooth HCI.  -bt options
2772are matched with the HCIs present in the chosen machine type.  For
2773example when emulating a machine with only one HCI built into it, only
2774the first @code{-bt hci[...]} option is valid and defines the HCI's
2775logic.  The Transport Layer is decided by the machine type.  Currently
2776the machines @code{n800} and @code{n810} have one HCI and all other
2777machines have none.
2778
2779Note: This option and the whole bluetooth subsystem is considered as deprecated.
2780If you still use it, please send a mail to @email{qemu-devel@@nongnu.org} where
2781you describe your usecase.
2782
2783@anchor{bt-hcis}
2784The following three types are recognized:
2785
2786@table @option
2787@item -bt hci,null
2788(default) The corresponding Bluetooth HCI assumes no internal logic
2789and will not respond to any HCI commands or emit events.
2790
2791@item -bt hci,host[:@var{id}]
2792(@code{bluez} only) The corresponding HCI passes commands / events
2793to / from the physical HCI identified by the name @var{id} (default:
2794@code{hci0}) on the computer running QEMU.  Only available on @code{bluez}
2795capable systems like Linux.
2796
2797@item -bt hci[,vlan=@var{n}]
2798Add a virtual, standard HCI that will participate in the Bluetooth
2799scatternet @var{n} (default @code{0}).  Similarly to @option{-net}
2800VLANs, devices inside a bluetooth network @var{n} can only communicate
2801with other devices in the same network (scatternet).
2802@end table
2803
2804@item -bt vhci[,vlan=@var{n}]
2805(Linux-host only) Create a HCI in scatternet @var{n} (default 0) attached
2806to the host bluetooth stack instead of to the emulated target.  This
2807allows the host and target machines to participate in a common scatternet
2808and communicate.  Requires the Linux @code{vhci} driver installed.  Can
2809be used as following:
2810
2811@example
2812qemu-system-i386 [...OPTIONS...] -bt hci,vlan=5 -bt vhci,vlan=5
2813@end example
2814
2815@item -bt device:@var{dev}[,vlan=@var{n}]
2816Emulate a bluetooth device @var{dev} and place it in network @var{n}
2817(default @code{0}).  QEMU can only emulate one type of bluetooth devices
2818currently:
2819
2820@table @option
2821@item keyboard
2822Virtual wireless keyboard implementing the HIDP bluetooth profile.
2823@end table
2824ETEXI
2825
2826STEXI
2827@end table
2828ETEXI
2829DEFHEADING()
2830
2831#ifdef CONFIG_TPM
2832DEFHEADING(TPM device options:)
2833
2834DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
2835    "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n"
2836    "                use path to provide path to a character device; default is /dev/tpm0\n"
2837    "                use cancel-path to provide path to TPM's cancel sysfs entry; if\n"
2838    "                not provided it will be searched for in /sys/class/misc/tpm?/device\n"
2839    "-tpmdev emulator,id=id,chardev=dev\n"
2840    "                configure the TPM device using chardev backend\n",
2841    QEMU_ARCH_ALL)
2842STEXI
2843
2844The general form of a TPM device option is:
2845@table @option
2846
2847@item -tpmdev @var{backend},id=@var{id}[,@var{options}]
2848@findex -tpmdev
2849
2850The specific backend type will determine the applicable options.
2851The @code{-tpmdev} option creates the TPM backend and requires a
2852@code{-device} option that specifies the TPM frontend interface model.
2853
2854Use @code{-tpmdev help} to print all available TPM backend types.
2855
2856@end table
2857
2858The available backends are:
2859
2860@table @option
2861
2862@item -tpmdev passthrough,id=@var{id},path=@var{path},cancel-path=@var{cancel-path}
2863
2864(Linux-host only) Enable access to the host's TPM using the passthrough
2865driver.
2866
2867@option{path} specifies the path to the host's TPM device, i.e., on
2868a Linux host this would be @code{/dev/tpm0}.
2869@option{path} is optional and by default @code{/dev/tpm0} is used.
2870
2871@option{cancel-path} specifies the path to the host TPM device's sysfs
2872entry allowing for cancellation of an ongoing TPM command.
2873@option{cancel-path} is optional and by default QEMU will search for the
2874sysfs entry to use.
2875
2876Some notes about using the host's TPM with the passthrough driver:
2877
2878The TPM device accessed by the passthrough driver must not be
2879used by any other application on the host.
2880
2881Since the host's firmware (BIOS/UEFI) has already initialized the TPM,
2882the VM's firmware (BIOS/UEFI) will not be able to initialize the
2883TPM again and may therefore not show a TPM-specific menu that would
2884otherwise allow the user to configure the TPM, e.g., allow the user to
2885enable/disable or activate/deactivate the TPM.
2886Further, if TPM ownership is released from within a VM then the host's TPM
2887will get disabled and deactivated. To enable and activate the
2888TPM again afterwards, the host has to be rebooted and the user is
2889required to enter the firmware's menu to enable and activate the TPM.
2890If the TPM is left disabled and/or deactivated most TPM commands will fail.
2891
2892To create a passthrough TPM use the following two options:
2893@example
2894-tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0
2895@end example
2896Note that the @code{-tpmdev} id is @code{tpm0} and is referenced by
2897@code{tpmdev=tpm0} in the device option.
2898
2899@item -tpmdev emulator,id=@var{id},chardev=@var{dev}
2900
2901(Linux-host only) Enable access to a TPM emulator using Unix domain socket based
2902chardev backend.
2903
2904@option{chardev} specifies the unique ID of a character device backend that provides connection to the software TPM server.
2905
2906To create a TPM emulator backend device with chardev socket backend:
2907@example
2908
2909-chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
2910
2911@end example
2912
2913ETEXI
2914
2915STEXI
2916@end table
2917ETEXI
2918DEFHEADING()
2919
2920#endif
2921
2922DEFHEADING(Linux/Multiboot boot specific:)
2923STEXI
2924
2925When using these options, you can use a given Linux or Multiboot
2926kernel without installing it in the disk image. It can be useful
2927for easier testing of various kernels.
2928
2929@table @option
2930ETEXI
2931
2932DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
2933    "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
2934STEXI
2935@item -kernel @var{bzImage}
2936@findex -kernel
2937Use @var{bzImage} as kernel image. The kernel can be either a Linux kernel
2938or in multiboot format.
2939ETEXI
2940
2941DEF("append", HAS_ARG, QEMU_OPTION_append, \
2942    "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL)
2943STEXI
2944@item -append @var{cmdline}
2945@findex -append
2946Use @var{cmdline} as kernel command line
2947ETEXI
2948
2949DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \
2950           "-initrd file    use 'file' as initial ram disk\n", QEMU_ARCH_ALL)
2951STEXI
2952@item -initrd @var{file}
2953@findex -initrd
2954Use @var{file} as initial ram disk.
2955
2956@item -initrd "@var{file1} arg=foo,@var{file2}"
2957
2958This syntax is only available with multiboot.
2959
2960Use @var{file1} and @var{file2} as modules and pass arg=foo as parameter to the
2961first module.
2962ETEXI
2963
2964DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
2965    "-dtb    file    use 'file' as device tree image\n", QEMU_ARCH_ALL)
2966STEXI
2967@item -dtb @var{file}
2968@findex -dtb
2969Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
2970on boot.
2971ETEXI
2972
2973STEXI
2974@end table
2975ETEXI
2976DEFHEADING()
2977
2978DEFHEADING(Debug/Expert options:)
2979STEXI
2980@table @option
2981ETEXI
2982
2983DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg,
2984    "-fw_cfg [name=]<name>,file=<file>\n"
2985    "                add named fw_cfg entry with contents from file\n"
2986    "-fw_cfg [name=]<name>,string=<str>\n"
2987    "                add named fw_cfg entry with contents from string\n",
2988    QEMU_ARCH_ALL)
2989STEXI
2990
2991@item -fw_cfg [name=]@var{name},file=@var{file}
2992@findex -fw_cfg
2993Add named fw_cfg entry with contents from file @var{file}.
2994
2995@item -fw_cfg [name=]@var{name},string=@var{str}
2996Add named fw_cfg entry with contents from string @var{str}.
2997
2998The terminating NUL character of the contents of @var{str} will not be
2999included as part of the fw_cfg item data. To insert contents with
3000embedded NUL characters, you have to use the @var{file} parameter.
3001
3002The fw_cfg entries are passed by QEMU through to the guest.
3003
3004Example:
3005@example
3006    -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin
3007@end example
3008creates an fw_cfg entry named opt/com.mycompany/blob with contents
3009from ./my_blob.bin.
3010
3011ETEXI
3012
3013DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
3014    "-serial dev     redirect the serial port to char device 'dev'\n",
3015    QEMU_ARCH_ALL)
3016STEXI
3017@item -serial @var{dev}
3018@findex -serial
3019Redirect the virtual serial port to host character device
3020@var{dev}. The default device is @code{vc} in graphical mode and
3021@code{stdio} in non graphical mode.
3022
3023This option can be used several times to simulate up to 4 serial
3024ports.
3025
3026Use @code{-serial none} to disable all serial ports.
3027
3028Available character devices are:
3029@table @option
3030@item vc[:@var{W}x@var{H}]
3031Virtual console. Optionally, a width and height can be given in pixel with
3032@example
3033vc:800x600
3034@end example
3035It is also possible to specify width or height in characters:
3036@example
3037vc:80Cx24C
3038@end example
3039@item pty
3040[Linux only] Pseudo TTY (a new PTY is automatically allocated)
3041@item none
3042No device is allocated.
3043@item null
3044void device
3045@item chardev:@var{id}
3046Use a named character device defined with the @code{-chardev} option.
3047@item /dev/XXX
3048[Linux only] Use host tty, e.g. @file{/dev/ttyS0}. The host serial port
3049parameters are set according to the emulated ones.
3050@item /dev/parport@var{N}
3051[Linux only, parallel port only] Use host parallel port
3052@var{N}. Currently SPP and EPP parallel port features can be used.
3053@item file:@var{filename}
3054Write output to @var{filename}. No character can be read.
3055@item stdio
3056[Unix only] standard input/output
3057@item pipe:@var{filename}
3058name pipe @var{filename}
3059@item COM@var{n}
3060[Windows only] Use host serial port @var{n}
3061@item udp:[@var{remote_host}]:@var{remote_port}[@@[@var{src_ip}]:@var{src_port}]
3062This implements UDP Net Console.
3063When @var{remote_host} or @var{src_ip} are not specified
3064they default to @code{0.0.0.0}.
3065When not using a specified @var{src_port} a random port is automatically chosen.
3066
3067If you just want a simple readonly console you can use @code{netcat} or
3068@code{nc}, by starting QEMU with: @code{-serial udp::4555} and nc as:
3069@code{nc -u -l -p 4555}. Any time QEMU writes something to that port it
3070will appear in the netconsole session.
3071
3072If you plan to send characters back via netconsole or you want to stop
3073and start QEMU a lot of times, you should have QEMU use the same
3074source port each time by using something like @code{-serial
3075udp::4555@@:4556} to QEMU. Another approach is to use a patched
3076version of netcat which can listen to a TCP port and send and receive
3077characters via udp.  If you have a patched version of netcat which
3078activates telnet remote echo and single char transfer, then you can
3079use the following options to set up a netcat redirector to allow
3080telnet on port 5555 to access the QEMU port.
3081@table @code
3082@item QEMU Options:
3083-serial udp::4555@@:4556
3084@item netcat options:
3085-u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T
3086@item telnet options:
3087localhost 5555
3088@end table
3089
3090@item tcp:[@var{host}]:@var{port}[,@var{server}][,nowait][,nodelay][,reconnect=@var{seconds}]
3091The TCP Net Console has two modes of operation.  It can send the serial
3092I/O to a location or wait for a connection from a location.  By default
3093the TCP Net Console is sent to @var{host} at the @var{port}.  If you use
3094the @var{server} option QEMU will wait for a client socket application
3095to connect to the port before continuing, unless the @code{nowait}
3096option was specified.  The @code{nodelay} option disables the Nagle buffering
3097algorithm.  The @code{reconnect} option only applies if @var{noserver} is
3098set, if the connection goes down it will attempt to reconnect at the
3099given interval.  If @var{host} is omitted, 0.0.0.0 is assumed. Only
3100one TCP connection at a time is accepted. You can use @code{telnet} to
3101connect to the corresponding character device.
3102@table @code
3103@item Example to send tcp console to 192.168.0.2 port 4444
3104-serial tcp:192.168.0.2:4444
3105@item Example to listen and wait on port 4444 for connection
3106-serial tcp::4444,server
3107@item Example to not wait and listen on ip 192.168.0.100 port 4444
3108-serial tcp:192.168.0.100:4444,server,nowait
3109@end table
3110
3111@item telnet:@var{host}:@var{port}[,server][,nowait][,nodelay]
3112The telnet protocol is used instead of raw tcp sockets.  The options
3113work the same as if you had specified @code{-serial tcp}.  The
3114difference is that the port acts like a telnet server or client using
3115telnet option negotiation.  This will also allow you to send the
3116MAGIC_SYSRQ sequence if you use a telnet that supports sending the break
3117sequence.  Typically in unix telnet you do it with Control-] and then
3118type "send break" followed by pressing the enter key.
3119
3120@item websocket:@var{host}:@var{port},server[,nowait][,nodelay]
3121The WebSocket protocol is used instead of raw tcp socket. The port acts as
3122a WebSocket server. Client mode is not supported.
3123
3124@item unix:@var{path}[,server][,nowait][,reconnect=@var{seconds}]
3125A unix domain socket is used instead of a tcp socket.  The option works the
3126same as if you had specified @code{-serial tcp} except the unix domain socket
3127@var{path} is used for connections.
3128
3129@item mon:@var{dev_string}
3130This is a special option to allow the monitor to be multiplexed onto
3131another serial port.  The monitor is accessed with key sequence of
3132@key{Control-a} and then pressing @key{c}.
3133@var{dev_string} should be any one of the serial devices specified
3134above.  An example to multiplex the monitor onto a telnet server
3135listening on port 4444 would be:
3136@table @code
3137@item -serial mon:telnet::4444,server,nowait
3138@end table
3139When the monitor is multiplexed to stdio in this way, Ctrl+C will not terminate
3140QEMU any more but will be passed to the guest instead.
3141
3142@item braille
3143Braille device.  This will use BrlAPI to display the braille output on a real
3144or fake device.
3145
3146@item msmouse
3147Three button serial mouse. Configure the guest to use Microsoft protocol.
3148@end table
3149ETEXI
3150
3151DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \
3152    "-parallel dev   redirect the parallel port to char device 'dev'\n",
3153    QEMU_ARCH_ALL)
3154STEXI
3155@item -parallel @var{dev}
3156@findex -parallel
3157Redirect the virtual parallel port to host device @var{dev} (same
3158devices as the serial port). On Linux hosts, @file{/dev/parportN} can
3159be used to use hardware devices connected on the corresponding host
3160parallel port.
3161
3162This option can be used several times to simulate up to 3 parallel
3163ports.
3164
3165Use @code{-parallel none} to disable all parallel ports.
3166ETEXI
3167
3168DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \
3169    "-monitor dev    redirect the monitor to char device 'dev'\n",
3170    QEMU_ARCH_ALL)
3171STEXI
3172@item -monitor @var{dev}
3173@findex -monitor
3174Redirect the monitor to host device @var{dev} (same devices as the
3175serial port).
3176The default device is @code{vc} in graphical mode and @code{stdio} in
3177non graphical mode.
3178Use @code{-monitor none} to disable the default monitor.
3179ETEXI
3180DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \
3181    "-qmp dev        like -monitor but opens in 'control' mode\n",
3182    QEMU_ARCH_ALL)
3183STEXI
3184@item -qmp @var{dev}
3185@findex -qmp
3186Like -monitor but opens in 'control' mode.
3187ETEXI
3188DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \
3189    "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n",
3190    QEMU_ARCH_ALL)
3191STEXI
3192@item -qmp-pretty @var{dev}
3193@findex -qmp-pretty
3194Like -qmp but uses pretty JSON formatting.
3195ETEXI
3196
3197DEF("mon", HAS_ARG, QEMU_OPTION_mon, \
3198    "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL)
3199STEXI
3200@item -mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]
3201@findex -mon
3202Setup monitor on chardev @var{name}. @code{pretty} turns on JSON pretty printing
3203easing human reading and debugging.
3204ETEXI
3205
3206DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \
3207    "-debugcon dev   redirect the debug console to char device 'dev'\n",
3208    QEMU_ARCH_ALL)
3209STEXI
3210@item -debugcon @var{dev}
3211@findex -debugcon
3212Redirect the debug console to host device @var{dev} (same devices as the
3213serial port).  The debug console is an I/O port which is typically port
32140xe9; writing to that I/O port sends output to this device.
3215The default device is @code{vc} in graphical mode and @code{stdio} in
3216non graphical mode.
3217ETEXI
3218
3219DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \
3220    "-pidfile file   write PID to 'file'\n", QEMU_ARCH_ALL)
3221STEXI
3222@item -pidfile @var{file}
3223@findex -pidfile
3224Store the QEMU process PID in @var{file}. It is useful if you launch QEMU
3225from a script.
3226ETEXI
3227
3228DEF("singlestep", 0, QEMU_OPTION_singlestep, \
3229    "-singlestep     always run in singlestep mode\n", QEMU_ARCH_ALL)
3230STEXI
3231@item -singlestep
3232@findex -singlestep
3233Run the emulation in single step mode.
3234ETEXI
3235
3236DEF("preconfig", 0, QEMU_OPTION_preconfig, \
3237    "--preconfig     pause QEMU before machine is initialized (experimental)\n",
3238    QEMU_ARCH_ALL)
3239STEXI
3240@item --preconfig
3241@findex --preconfig
3242Pause QEMU for interactive configuration before the machine is created,
3243which allows querying and configuring properties that will affect
3244machine initialization.  Use QMP command 'x-exit-preconfig' to exit
3245the preconfig state and move to the next state (i.e. run guest if -S
3246isn't used or pause the second time if -S is used).  This option is
3247experimental.
3248ETEXI
3249
3250DEF("S", 0, QEMU_OPTION_S, \
3251    "-S              freeze CPU at startup (use 'c' to start execution)\n",
3252    QEMU_ARCH_ALL)
3253STEXI
3254@item -S
3255@findex -S
3256Do not start CPU at startup (you must type 'c' in the monitor).
3257ETEXI
3258
3259DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
3260    "-realtime [mlock=on|off]\n"
3261    "                run qemu with realtime features\n"
3262    "                mlock=on|off controls mlock support (default: on)\n",
3263    QEMU_ARCH_ALL)
3264STEXI
3265@item -realtime mlock=on|off
3266@findex -realtime
3267Run qemu with realtime features.
3268mlocking qemu and guest memory can be enabled via @option{mlock=on}
3269(enabled by default).
3270ETEXI
3271
3272DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit,
3273    "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n"
3274    "                run qemu with overcommit hints\n"
3275    "                mem-lock=on|off controls memory lock support (default: off)\n"
3276    "                cpu-pm=on|off controls cpu power management (default: off)\n",
3277    QEMU_ARCH_ALL)
3278STEXI
3279@item -overcommit mem-lock=on|off
3280@item -overcommit cpu-pm=on|off
3281@findex -overcommit
3282Run qemu with hints about host resource overcommit. The default is
3283to assume that host overcommits all resources.
3284
3285Locking qemu and guest memory can be enabled via @option{mem-lock=on} (disabled
3286by default).  This works when host memory is not overcommitted and reduces the
3287worst-case latency for guest.  This is equivalent to @option{realtime}.
3288
3289Guest ability to manage power state of host cpus (increasing latency for other
3290processes on the same host cpu, but decreasing latency for guest) can be
3291enabled via @option{cpu-pm=on} (disabled by default).  This works best when
3292host CPU is not overcommitted. When used, host estimates of CPU cycle and power
3293utilization will be incorrect, not taking into account guest idle time.
3294ETEXI
3295
3296DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
3297    "-gdb dev        wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
3298STEXI
3299@item -gdb @var{dev}
3300@findex -gdb
3301Wait for gdb connection on device @var{dev} (@pxref{gdb_usage}). Typical
3302connections will likely be TCP-based, but also UDP, pseudo TTY, or even
3303stdio are reasonable use case. The latter is allowing to start QEMU from
3304within gdb and establish the connection via a pipe:
3305@example
3306(gdb) target remote | exec qemu-system-i386 -gdb stdio ...
3307@end example
3308ETEXI
3309
3310DEF("s", 0, QEMU_OPTION_s, \
3311    "-s              shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n",
3312    QEMU_ARCH_ALL)
3313STEXI
3314@item -s
3315@findex -s
3316Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234
3317(@pxref{gdb_usage}).
3318ETEXI
3319
3320DEF("d", HAS_ARG, QEMU_OPTION_d, \
3321    "-d item1,...    enable logging of specified items (use '-d help' for a list of log items)\n",
3322    QEMU_ARCH_ALL)
3323STEXI
3324@item -d @var{item1}[,...]
3325@findex -d
3326Enable logging of specified items. Use '-d help' for a list of log items.
3327ETEXI
3328
3329DEF("D", HAS_ARG, QEMU_OPTION_D, \
3330    "-D logfile      output log to logfile (default stderr)\n",
3331    QEMU_ARCH_ALL)
3332STEXI
3333@item -D @var{logfile}
3334@findex -D
3335Output log in @var{logfile} instead of to stderr
3336ETEXI
3337
3338DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
3339    "-dfilter range,..  filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n",
3340    QEMU_ARCH_ALL)
3341STEXI
3342@item -dfilter @var{range1}[,...]
3343@findex -dfilter
3344Filter debug output to that relevant to a range of target addresses. The filter
3345spec can be either @var{start}+@var{size}, @var{start}-@var{size} or
3346@var{start}..@var{end} where @var{start} @var{end} and @var{size} are the
3347addresses and sizes required. For example:
3348@example
3349    -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
3350@end example
3351Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
3352the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
3353block starting at 0xffffffc00005f000.
3354ETEXI
3355
3356DEF("L", HAS_ARG, QEMU_OPTION_L, \
3357    "-L path         set the directory for the BIOS, VGA BIOS and keymaps\n",
3358    QEMU_ARCH_ALL)
3359STEXI
3360@item -L  @var{path}
3361@findex -L
3362Set the directory for the BIOS, VGA BIOS and keymaps.
3363
3364To list all the data directories, use @code{-L help}.
3365ETEXI
3366
3367DEF("bios", HAS_ARG, QEMU_OPTION_bios, \
3368    "-bios file      set the filename for the BIOS\n", QEMU_ARCH_ALL)
3369STEXI
3370@item -bios @var{file}
3371@findex -bios
3372Set the filename for the BIOS.
3373ETEXI
3374
3375DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \
3376    "-enable-kvm     enable KVM full virtualization support\n", QEMU_ARCH_ALL)
3377STEXI
3378@item -enable-kvm
3379@findex -enable-kvm
3380Enable KVM full virtualization support. This option is only available
3381if KVM support is enabled when compiling.
3382ETEXI
3383
3384DEF("enable-hax", 0, QEMU_OPTION_enable_hax, \
3385    "-enable-hax     enable HAX virtualization support\n", QEMU_ARCH_I386)
3386STEXI
3387@item -enable-hax
3388@findex -enable-hax
3389Enable HAX (Hardware-based Acceleration eXecution) support. This option
3390is only available if HAX support is enabled when compiling. HAX is only
3391applicable to MAC and Windows platform, and thus does not conflict with
3392KVM. This option is deprecated, use @option{-accel hax} instead.
3393ETEXI
3394
3395DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid,
3396    "-xen-domid id   specify xen guest domain id\n", QEMU_ARCH_ALL)
3397DEF("xen-create", 0, QEMU_OPTION_xen_create,
3398    "-xen-create     create domain using xen hypercalls, bypassing xend\n"
3399    "                warning: should not be used when xend is in use\n",
3400    QEMU_ARCH_ALL)
3401DEF("xen-attach", 0, QEMU_OPTION_xen_attach,
3402    "-xen-attach     attach to existing xen domain\n"
3403    "                xend will use this when starting QEMU\n",
3404    QEMU_ARCH_ALL)
3405DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict,
3406    "-xen-domid-restrict     restrict set of available xen operations\n"
3407    "                        to specified domain id. (Does not affect\n"
3408    "                        xenpv machine type).\n",
3409    QEMU_ARCH_ALL)
3410STEXI
3411@item -xen-domid @var{id}
3412@findex -xen-domid
3413Specify xen guest domain @var{id} (XEN only).
3414@item -xen-create
3415@findex -xen-create
3416Create domain using xen hypercalls, bypassing xend.
3417Warning: should not be used when xend is in use (XEN only).
3418@item -xen-attach
3419@findex -xen-attach
3420Attach to existing xen domain.
3421xend will use this when starting QEMU (XEN only).
3422@findex -xen-domid-restrict
3423Restrict set of available xen operations to specified domain id (XEN only).
3424ETEXI
3425
3426DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \
3427    "-no-reboot      exit instead of rebooting\n", QEMU_ARCH_ALL)
3428STEXI
3429@item -no-reboot
3430@findex -no-reboot
3431Exit instead of rebooting.
3432ETEXI
3433
3434DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \
3435    "-no-shutdown    stop before shutdown\n", QEMU_ARCH_ALL)
3436STEXI
3437@item -no-shutdown
3438@findex -no-shutdown
3439Don't exit QEMU on guest shutdown, but instead only stop the emulation.
3440This allows for instance switching to monitor to commit changes to the
3441disk image.
3442ETEXI
3443
3444DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \
3445    "-loadvm [tag|id]\n" \
3446    "                start right away with a saved state (loadvm in monitor)\n",
3447    QEMU_ARCH_ALL)
3448STEXI
3449@item -loadvm @var{file}
3450@findex -loadvm
3451Start right away with a saved state (@code{loadvm} in monitor)
3452ETEXI
3453
3454#ifndef _WIN32
3455DEF("daemonize", 0, QEMU_OPTION_daemonize, \
3456    "-daemonize      daemonize QEMU after initializing\n", QEMU_ARCH_ALL)
3457#endif
3458STEXI
3459@item -daemonize
3460@findex -daemonize
3461Daemonize the QEMU process after initialization.  QEMU will not detach from
3462standard IO until it is ready to receive connections on any of its devices.
3463This option is a useful way for external programs to launch QEMU without having
3464to cope with initialization race conditions.
3465ETEXI
3466
3467DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \
3468    "-option-rom rom load a file, rom, into the option ROM space\n",
3469    QEMU_ARCH_ALL)
3470STEXI
3471@item -option-rom @var{file}
3472@findex -option-rom
3473Load the contents of @var{file} as an option ROM.
3474This option is useful to load things like EtherBoot.
3475ETEXI
3476
3477HXCOMM Silently ignored for compatibility
3478DEF("clock", HAS_ARG, QEMU_OPTION_clock, "", QEMU_ARCH_ALL)
3479
3480DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
3481    "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \
3482    "                set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n",
3483    QEMU_ARCH_ALL)
3484
3485STEXI
3486
3487@item -rtc [base=utc|localtime|@var{datetime}][,clock=host|rt|vm][,driftfix=none|slew]
3488@findex -rtc
3489Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start at the current
3490UTC or local time, respectively. @code{localtime} is required for correct date in
3491MS-DOS or Windows. To start at a specific point in time, provide @var{datetime} in the
3492format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is UTC.
3493
3494By default the RTC is driven by the host system time. This allows using of the
3495RTC as accurate reference clock inside the guest, specifically if the host
3496time is smoothly following an accurate external reference clock, e.g. via NTP.
3497If you want to isolate the guest time from the host, you can set @option{clock}
3498to @code{rt} instead, which provides a host monotonic clock if host support it.
3499To even prevent the RTC from progressing during suspension, you can set @option{clock}
3500to @code{vm} (virtual clock). @samp{clock=vm} is recommended especially in
3501icount mode in order to preserve determinism; however, note that in icount mode
3502the speed of the virtual clock is variable and can in general differ from the
3503host clock.
3504
3505Enable @option{driftfix} (i386 targets only) if you experience time drift problems,
3506specifically with Windows' ACPI HAL. This option will try to figure out how
3507many timer interrupts were not processed by the Windows guest and will
3508re-inject them.
3509ETEXI
3510
3511DEF("icount", HAS_ARG, QEMU_OPTION_icount, \
3512    "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \
3513    "                enable virtual instruction counter with 2^N clock ticks per\n" \
3514    "                instruction, enable aligning the host and virtual clocks\n" \
3515    "                or disable real time cpu sleeping\n", QEMU_ARCH_ALL)
3516STEXI
3517@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}]
3518@findex -icount
3519Enable virtual instruction counter.  The virtual cpu will execute one
3520instruction every 2^@var{N} ns of virtual time.  If @code{auto} is specified
3521then the virtual cpu speed will be automatically adjusted to keep virtual
3522time within a few seconds of real time.
3523
3524When the virtual cpu is sleeping, the virtual time will advance at default
3525speed unless @option{sleep=on|off} is specified.
3526With @option{sleep=on|off}, the virtual time will jump to the next timer deadline
3527instantly whenever the virtual cpu goes to sleep mode and will not advance
3528if no timer is enabled. This behavior give deterministic execution times from
3529the guest point of view.
3530
3531Note that while this option can give deterministic behavior, it does not
3532provide cycle accurate emulation.  Modern CPUs contain superscalar out of
3533order cores with complex cache hierarchies.  The number of instructions
3534executed often has little or no correlation with actual performance.
3535
3536@option{align=on} will activate the delay algorithm which will try
3537to synchronise the host clock and the virtual clock. The goal is to
3538have a guest running at the real frequency imposed by the shift option.
3539Whenever the guest clock is behind the host clock and if
3540@option{align=on} is specified then we print a message to the user
3541to inform about the delay.
3542Currently this option does not work when @option{shift} is @code{auto}.
3543Note: The sync algorithm will work for those shift values for which
3544the guest clock runs ahead of the host clock. Typically this happens
3545when the shift value is high (how high depends on the host machine).
3546
3547When @option{rr} option is specified deterministic record/replay is enabled.
3548Replay log is written into @var{filename} file in record mode and
3549read from this file in replay mode.
3550
3551Option rrsnapshot is used to create new vm snapshot named @var{snapshot}
3552at the start of execution recording. In replay mode this option is used
3553to load the initial VM state.
3554ETEXI
3555
3556DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
3557    "-watchdog model\n" \
3558    "                enable virtual hardware watchdog [default=none]\n",
3559    QEMU_ARCH_ALL)
3560STEXI
3561@item -watchdog @var{model}
3562@findex -watchdog
3563Create a virtual hardware watchdog device.  Once enabled (by a guest
3564action), the watchdog must be periodically polled by an agent inside
3565the guest or else the guest will be restarted. Choose a model for
3566which your guest has drivers.
3567
3568The @var{model} is the model of hardware watchdog to emulate. Use
3569@code{-watchdog help} to list available hardware models. Only one
3570watchdog can be enabled for a guest.
3571
3572The following models may be available:
3573@table @option
3574@item ib700
3575iBASE 700 is a very simple ISA watchdog with a single timer.
3576@item i6300esb
3577Intel 6300ESB I/O controller hub is a much more featureful PCI-based
3578dual-timer watchdog.
3579@item diag288
3580A virtual watchdog for s390x backed by the diagnose 288 hypercall
3581(currently KVM only).
3582@end table
3583ETEXI
3584
3585DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
3586    "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \
3587    "                action when watchdog fires [default=reset]\n",
3588    QEMU_ARCH_ALL)
3589STEXI
3590@item -watchdog-action @var{action}
3591@findex -watchdog-action
3592
3593The @var{action} controls what QEMU will do when the watchdog timer
3594expires.
3595The default is
3596@code{reset} (forcefully reset the guest).
3597Other possible actions are:
3598@code{shutdown} (attempt to gracefully shutdown the guest),
3599@code{poweroff} (forcefully poweroff the guest),
3600@code{inject-nmi} (inject a NMI into the guest),
3601@code{pause} (pause the guest),
3602@code{debug} (print a debug message and continue), or
3603@code{none} (do nothing).
3604
3605Note that the @code{shutdown} action requires that the guest responds
3606to ACPI signals, which it may not be able to do in the sort of
3607situations where the watchdog would have expired, and thus
3608@code{-watchdog-action shutdown} is not recommended for production use.
3609
3610Examples:
3611
3612@table @code
3613@item -watchdog i6300esb -watchdog-action pause
3614@itemx -watchdog ib700
3615@end table
3616ETEXI
3617
3618DEF("echr", HAS_ARG, QEMU_OPTION_echr, \
3619    "-echr chr       set terminal escape character instead of ctrl-a\n",
3620    QEMU_ARCH_ALL)
3621STEXI
3622
3623@item -echr @var{numeric_ascii_value}
3624@findex -echr
3625Change the escape character used for switching to the monitor when using
3626monitor and serial sharing.  The default is @code{0x01} when using the
3627@code{-nographic} option.  @code{0x01} is equal to pressing
3628@code{Control-a}.  You can select a different character from the ascii
3629control keys where 1 through 26 map to Control-a through Control-z.  For
3630instance you could use the either of the following to change the escape
3631character to Control-t.
3632@table @code
3633@item -echr 0x14
3634@itemx -echr 20
3635@end table
3636ETEXI
3637
3638DEF("virtioconsole", HAS_ARG, QEMU_OPTION_virtiocon, \
3639    "-virtioconsole c\n" \
3640    "                set virtio console\n", QEMU_ARCH_ALL)
3641STEXI
3642@item -virtioconsole @var{c}
3643@findex -virtioconsole
3644Set virtio console.
3645This option is deprecated, please use @option{-device virtconsole} instead.
3646ETEXI
3647
3648DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
3649    "-show-cursor    show cursor\n", QEMU_ARCH_ALL)
3650STEXI
3651@item -show-cursor
3652@findex -show-cursor
3653Show cursor.
3654ETEXI
3655
3656DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
3657    "-tb-size n      set TB size\n", QEMU_ARCH_ALL)
3658STEXI
3659@item -tb-size @var{n}
3660@findex -tb-size
3661Set TB size.
3662ETEXI
3663
3664DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
3665    "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \
3666    "-incoming rdma:host:port[,ipv4][,ipv6]\n" \
3667    "-incoming unix:socketpath\n" \
3668    "                prepare for incoming migration, listen on\n" \
3669    "                specified protocol and socket address\n" \
3670    "-incoming fd:fd\n" \
3671    "-incoming exec:cmdline\n" \
3672    "                accept incoming migration on given file descriptor\n" \
3673    "                or from given external command\n" \
3674    "-incoming defer\n" \
3675    "                wait for the URI to be specified via migrate_incoming\n",
3676    QEMU_ARCH_ALL)
3677STEXI
3678@item -incoming tcp:[@var{host}]:@var{port}[,to=@var{maxport}][,ipv4][,ipv6]
3679@itemx -incoming rdma:@var{host}:@var{port}[,ipv4][,ipv6]
3680@findex -incoming
3681Prepare for incoming migration, listen on a given tcp port.
3682
3683@item -incoming unix:@var{socketpath}
3684Prepare for incoming migration, listen on a given unix socket.
3685
3686@item -incoming fd:@var{fd}
3687Accept incoming migration from a given filedescriptor.
3688
3689@item -incoming exec:@var{cmdline}
3690Accept incoming migration as an output from specified external command.
3691
3692@item -incoming defer
3693Wait for the URI to be specified via migrate_incoming.  The monitor can
3694be used to change settings (such as migration parameters) prior to issuing
3695the migrate_incoming to allow the migration to begin.
3696ETEXI
3697
3698DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \
3699    "-only-migratable     allow only migratable devices\n", QEMU_ARCH_ALL)
3700STEXI
3701@item -only-migratable
3702@findex -only-migratable
3703Only allow migratable devices. Devices will not be allowed to enter an
3704unmigratable state.
3705ETEXI
3706
3707DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
3708    "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
3709STEXI
3710@item -nodefaults
3711@findex -nodefaults
3712Don't create default devices. Normally, QEMU sets the default devices like serial
3713port, parallel port, virtual console, monitor device, VGA adapter, floppy and
3714CD-ROM drive and others. The @code{-nodefaults} option will disable all those
3715default devices.
3716ETEXI
3717
3718#ifndef _WIN32
3719DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \
3720    "-chroot dir     chroot to dir just before starting the VM\n",
3721    QEMU_ARCH_ALL)
3722#endif
3723STEXI
3724@item -chroot @var{dir}
3725@findex -chroot
3726Immediately before starting guest execution, chroot to the specified
3727directory.  Especially useful in combination with -runas.
3728ETEXI
3729
3730#ifndef _WIN32
3731DEF("runas", HAS_ARG, QEMU_OPTION_runas, \
3732    "-runas user     change to user id user just before starting the VM\n" \
3733    "                user can be numeric uid:gid instead\n",
3734    QEMU_ARCH_ALL)
3735#endif
3736STEXI
3737@item -runas @var{user}
3738@findex -runas
3739Immediately before starting guest execution, drop root privileges, switching
3740to the specified user.
3741ETEXI
3742
3743DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env,
3744    "-prom-env variable=value\n"
3745    "                set OpenBIOS nvram variables\n",
3746    QEMU_ARCH_PPC | QEMU_ARCH_SPARC)
3747STEXI
3748@item -prom-env @var{variable}=@var{value}
3749@findex -prom-env
3750Set OpenBIOS nvram @var{variable} to given @var{value} (PPC, SPARC only).
3751ETEXI
3752DEF("semihosting", 0, QEMU_OPTION_semihosting,
3753    "-semihosting    semihosting mode\n",
3754    QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3755    QEMU_ARCH_MIPS)
3756STEXI
3757@item -semihosting
3758@findex -semihosting
3759Enable semihosting mode (ARM, M68K, Xtensa, MIPS only).
3760ETEXI
3761DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
3762    "-semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
3763    "                semihosting configuration\n",
3764QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
3765QEMU_ARCH_MIPS)
3766STEXI
3767@item -semihosting-config [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]
3768@findex -semihosting-config
3769Enable and configure semihosting (ARM, M68K, Xtensa, MIPS only).
3770@table @option
3771@item target=@code{native|gdb|auto}
3772Defines where the semihosting calls will be addressed, to QEMU (@code{native})
3773or to GDB (@code{gdb}). The default is @code{auto}, which means @code{gdb}
3774during debug sessions and @code{native} otherwise.
3775@item arg=@var{str1},arg=@var{str2},...
3776Allows the user to pass input arguments, and can be used multiple times to build
3777up a list. The old-style @code{-kernel}/@code{-append} method of passing a
3778command line is still supported for backward compatibility. If both the
3779@code{--semihosting-config arg} and the @code{-kernel}/@code{-append} are
3780specified, the former is passed to semihosting as it always takes precedence.
3781@end table
3782ETEXI
3783DEF("old-param", 0, QEMU_OPTION_old_param,
3784    "-old-param      old param mode\n", QEMU_ARCH_ARM)
3785STEXI
3786@item -old-param
3787@findex -old-param (ARM)
3788Old param mode (ARM only).
3789ETEXI
3790
3791DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
3792    "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \
3793    "          [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \
3794    "                Enable seccomp mode 2 system call filter (default 'off').\n" \
3795    "                use 'obsolete' to allow obsolete system calls that are provided\n" \
3796    "                    by the kernel, but typically no longer used by modern\n" \
3797    "                    C library implementations.\n" \
3798    "                use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \
3799    "                    its privileges by blacklisting all set*uid|gid system calls.\n" \
3800    "                    The value 'children' will deny set*uid|gid system calls for\n" \
3801    "                    main QEMU process but will allow forks and execves to run unprivileged\n" \
3802    "                use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \
3803    "                     blacklisting *fork and execve\n" \
3804    "                use 'resourcecontrol' to disable process affinity and schedular priority\n",
3805    QEMU_ARCH_ALL)
3806STEXI
3807@item -sandbox @var{arg}[,obsolete=@var{string}][,elevateprivileges=@var{string}][,spawn=@var{string}][,resourcecontrol=@var{string}]
3808@findex -sandbox
3809Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
3810disable it.  The default is 'off'.
3811@table @option
3812@item obsolete=@var{string}
3813Enable Obsolete system calls
3814@item elevateprivileges=@var{string}
3815Disable set*uid|gid system calls
3816@item spawn=@var{string}
3817Disable *fork and execve
3818@item resourcecontrol=@var{string}
3819Disable process affinity and schedular priority
3820@end table
3821ETEXI
3822
3823DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
3824    "-readconfig <file>\n", QEMU_ARCH_ALL)
3825STEXI
3826@item -readconfig @var{file}
3827@findex -readconfig
3828Read device configuration from @var{file}. This approach is useful when you want to spawn
3829QEMU process with many command line options but you don't want to exceed the command line
3830character limit.
3831ETEXI
3832DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig,
3833    "-writeconfig <file>\n"
3834    "                read/write config file\n", QEMU_ARCH_ALL)
3835STEXI
3836@item -writeconfig @var{file}
3837@findex -writeconfig
3838Write device configuration to @var{file}. The @var{file} can be either filename to save
3839command line and device configuration into file or dash @code{-}) character to print the
3840output to stdout. This can be later used as input file for @code{-readconfig} option.
3841ETEXI
3842
3843DEF("no-user-config", 0, QEMU_OPTION_nouserconfig,
3844    "-no-user-config\n"
3845    "                do not load default user-provided config files at startup\n",
3846    QEMU_ARCH_ALL)
3847STEXI
3848@item -no-user-config
3849@findex -no-user-config
3850The @code{-no-user-config} option makes QEMU not load any of the user-provided
3851config files on @var{sysconfdir}.
3852ETEXI
3853
3854DEF("trace", HAS_ARG, QEMU_OPTION_trace,
3855    "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
3856    "                specify tracing options\n",
3857    QEMU_ARCH_ALL)
3858STEXI
3859HXCOMM This line is not accurate, as some sub-options are backend-specific but
3860HXCOMM HX does not support conditional compilation of text.
3861@item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
3862@findex -trace
3863@include qemu-option-trace.texi
3864ETEXI
3865
3866HXCOMM Internal use
3867DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL)
3868DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
3869
3870#ifdef __linux__
3871DEF("enable-fips", 0, QEMU_OPTION_enablefips,
3872    "-enable-fips    enable FIPS 140-2 compliance\n",
3873    QEMU_ARCH_ALL)
3874#endif
3875STEXI
3876@item -enable-fips
3877@findex -enable-fips
3878Enable FIPS 140-2 compliance mode.
3879ETEXI
3880
3881HXCOMM Deprecated by -machine accel=tcg property
3882DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
3883
3884DEF("msg", HAS_ARG, QEMU_OPTION_msg,
3885    "-msg timestamp[=on|off]\n"
3886    "                change the format of messages\n"
3887    "                on|off controls leading timestamps (default:on)\n",
3888    QEMU_ARCH_ALL)
3889STEXI
3890@item -msg timestamp[=on|off]
3891@findex -msg
3892prepend a timestamp to each log message.(default:on)
3893ETEXI
3894
3895DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
3896    "-dump-vmstate <file>\n"
3897    "                Output vmstate information in JSON format to file.\n"
3898    "                Use the scripts/vmstate-static-checker.py file to\n"
3899    "                check for possible regressions in migration code\n"
3900    "                by comparing two such vmstate dumps.\n",
3901    QEMU_ARCH_ALL)
3902STEXI
3903@item -dump-vmstate @var{file}
3904@findex -dump-vmstate
3905Dump json-encoded vmstate information for current machine type to file
3906in @var{file}
3907ETEXI
3908
3909DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile,
3910    "-enable-sync-profile\n"
3911    "                enable synchronization profiling\n",
3912    QEMU_ARCH_ALL)
3913STEXI
3914@item -enable-sync-profile
3915@findex -enable-sync-profile
3916Enable synchronization profiling.
3917ETEXI
3918
3919STEXI
3920@end table
3921ETEXI
3922DEFHEADING()
3923
3924DEFHEADING(Generic object creation:)
3925STEXI
3926@table @option
3927ETEXI
3928
3929DEF("object", HAS_ARG, QEMU_OPTION_object,
3930    "-object TYPENAME[,PROP1=VALUE1,...]\n"
3931    "                create a new object of type TYPENAME setting properties\n"
3932    "                in the order they are specified.  Note that the 'id'\n"
3933    "                property must be set.  These objects are placed in the\n"
3934    "                '/objects' path.\n",
3935    QEMU_ARCH_ALL)
3936STEXI
3937@item -object @var{typename}[,@var{prop1}=@var{value1},...]
3938@findex -object
3939Create a new object of type @var{typename} setting properties
3940in the order they are specified.  Note that the 'id'
3941property must be set.  These objects are placed in the
3942'/objects' path.
3943
3944@table @option
3945
3946@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}
3947
3948Creates a memory file backend object, which can be used to back
3949the guest RAM with huge pages.
3950
3951The @option{id} parameter is a unique ID that will be used to reference this
3952memory region when configuring the @option{-numa} argument.
3953
3954The @option{size} option provides the size of the memory region, and accepts
3955common suffixes, eg @option{500M}.
3956
3957The @option{mem-path} provides the path to either a shared memory or huge page
3958filesystem mount.
3959
3960The @option{share} boolean option determines whether the memory
3961region is marked as private to QEMU, or shared. The latter allows
3962a co-operating external process to access the QEMU memory region.
3963
3964The @option{share} is also required for pvrdma devices due to
3965limitations in the RDMA API provided by Linux.
3966
3967Setting share=on might affect the ability to configure NUMA
3968bindings for the memory backend under some circumstances, see
3969Documentation/vm/numa_memory_policy.txt on the Linux kernel
3970source tree for additional details.
3971
3972Setting the @option{discard-data} boolean option to @var{on}
3973indicates that file contents can be destroyed when QEMU exits,
3974to avoid unnecessarily flushing data to the backing file.  Note
3975that @option{discard-data} is only an optimization, and QEMU
3976might not discard file contents if it aborts unexpectedly or is
3977terminated using SIGKILL.
3978
3979The @option{merge} boolean option enables memory merge, also known as
3980MADV_MERGEABLE, so that Kernel Samepage Merging will consider the pages for
3981memory deduplication.
3982
3983Setting the @option{dump} boolean option to @var{off} excludes the memory from
3984core dumps. This feature is also known as MADV_DONTDUMP.
3985
3986The @option{prealloc} boolean option enables memory preallocation.
3987
3988The @option{host-nodes} option binds the memory range to a list of NUMA host
3989nodes.
3990
3991The @option{policy} option sets the NUMA policy to one of the following values:
3992
3993@table @option
3994@item @var{default}
3995default host policy
3996
3997@item @var{preferred}
3998prefer the given host node list for allocation
3999
4000@item @var{bind}
4001restrict memory allocation to the given host node list
4002
4003@item @var{interleave}
4004interleave memory allocations across the given host node list
4005@end table
4006
4007The @option{align} option specifies the base address alignment when
4008QEMU mmap(2) @option{mem-path}, and accepts common suffixes, eg
4009@option{2M}. Some backend store specified by @option{mem-path}
4010requires an alignment different than the default one used by QEMU, eg
4011the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In
4012such cases, users can specify the required alignment via this option.
4013
4014The @option{pmem} option specifies whether the backing file specified
4015by @option{mem-path} is in host persistent memory that can be accessed
4016using the SNIA NVM programming model (e.g. Intel NVDIMM).
4017If @option{pmem} is set to 'on', QEMU will take necessary operations to
4018guarantee the persistence of its own writes to @option{mem-path}
4019(e.g. in vNVDIMM label emulation and live migration).
4020
4021@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}
4022
4023Creates a memory backend object, which can be used to back the guest RAM.
4024Memory backend objects offer more control than the @option{-m} option that is
4025traditionally used to define guest RAM. Please refer to
4026@option{memory-backend-file} for a description of the options.
4027
4028@item -object memory-backend-memfd,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave},seal=@var{on|off},hugetlb=@var{on|off},hugetlbsize=@var{size}
4029
4030Creates an anonymous memory file backend object, which allows QEMU to
4031share the memory with an external process (e.g. when using
4032vhost-user). The memory is allocated with memfd and optional
4033sealing. (Linux only)
4034
4035The @option{seal} option creates a sealed-file, that will block
4036further resizing the memory ('on' by default).
4037
4038The @option{hugetlb} option specify the file to be created resides in
4039the hugetlbfs filesystem (since Linux 4.14).  Used in conjunction with
4040the @option{hugetlb} option, the @option{hugetlbsize} option specify
4041the hugetlb page size on systems that support multiple hugetlb page
4042sizes (it must be a power of 2 value supported by the system).
4043
4044In some versions of Linux, the @option{hugetlb} option is incompatible
4045with the @option{seal} option (requires at least Linux 4.16).
4046
4047Please refer to @option{memory-backend-file} for a description of the
4048other options.
4049
4050The @option{share} boolean option is @var{on} by default with memfd.
4051
4052@item -object rng-random,id=@var{id},filename=@var{/dev/random}
4053
4054Creates a random number generator backend which obtains entropy from
4055a device on the host. The @option{id} parameter is a unique ID that
4056will be used to reference this entropy backend from the @option{virtio-rng}
4057device. The @option{filename} parameter specifies which file to obtain
4058entropy from and if omitted defaults to @option{/dev/random}.
4059
4060@item -object rng-egd,id=@var{id},chardev=@var{chardevid}
4061
4062Creates a random number generator backend which obtains entropy from
4063an external daemon running on the host. The @option{id} parameter is
4064a unique ID that will be used to reference this entropy backend from
4065the @option{virtio-rng} device. The @option{chardev} parameter is
4066the unique ID of a character device backend that provides the connection
4067to the RNG daemon.
4068
4069@item -object tls-creds-anon,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/cred/dir},verify-peer=@var{on|off}
4070
4071Creates a TLS anonymous credentials object, which can be used to provide
4072TLS support on network backends. The @option{id} parameter is a unique
4073ID which network backends will use to access the credentials. The
4074@option{endpoint} is either @option{server} or @option{client} depending
4075on whether the QEMU network backend that uses the credentials will be
4076acting as a client or as a server. If @option{verify-peer} is enabled
4077(the default) then once the handshake is completed, the peer credentials
4078will be verified, though this is a no-op for anonymous credentials.
4079
4080The @var{dir} parameter tells QEMU where to find the credential
4081files. For server endpoints, this directory may contain a file
4082@var{dh-params.pem} providing diffie-hellman parameters to use
4083for the TLS server. If the file is missing, QEMU will generate
4084a set of DH parameters at startup. This is a computationally
4085expensive operation that consumes random pool entropy, so it is
4086recommended that a persistent set of parameters be generated
4087upfront and saved.
4088
4089@item -object tls-creds-psk,id=@var{id},endpoint=@var{endpoint},dir=@var{/path/to/keys/dir}[,username=@var{username}]
4090
4091Creates a TLS Pre-Shared Keys (PSK) credentials object, which can be used to provide
4092TLS support on network backends. The @option{id} parameter is a unique
4093ID which network backends will use to access the credentials. The
4094@option{endpoint} is either @option{server} or @option{client} depending
4095on whether the QEMU network backend that uses the credentials will be
4096acting as a client or as a server. For clients only, @option{username}
4097is the username which will be sent to the server.  If omitted
4098it defaults to ``qemu''.
4099
4100The @var{dir} parameter tells QEMU where to find the keys file.
4101It is called ``@var{dir}/keys.psk'' and contains ``username:key''
4102pairs.  This file can most easily be created using the GnuTLS
4103@code{psktool} program.
4104
4105For server endpoints, @var{dir} may also contain a file
4106@var{dh-params.pem} providing diffie-hellman parameters to use
4107for the TLS server. If the file is missing, QEMU will generate
4108a set of DH parameters at startup. This is a computationally
4109expensive operation that consumes random pool entropy, so it is
4110recommended that a persistent set of parameters be generated
4111up front and saved.
4112
4113@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}
4114
4115Creates a TLS anonymous credentials object, which can be used to provide
4116TLS support on network backends. The @option{id} parameter is a unique
4117ID which network backends will use to access the credentials. The
4118@option{endpoint} is either @option{server} or @option{client} depending
4119on whether the QEMU network backend that uses the credentials will be
4120acting as a client or as a server. If @option{verify-peer} is enabled
4121(the default) then once the handshake is completed, the peer credentials
4122will be verified. With x509 certificates, this implies that the clients
4123must be provided with valid client certificates too.
4124
4125The @var{dir} parameter tells QEMU where to find the credential
4126files. For server endpoints, this directory may contain a file
4127@var{dh-params.pem} providing diffie-hellman parameters to use
4128for the TLS server. If the file is missing, QEMU will generate
4129a set of DH parameters at startup. This is a computationally
4130expensive operation that consumes random pool entropy, so it is
4131recommended that a persistent set of parameters be generated
4132upfront and saved.
4133
4134For x509 certificate credentials the directory will contain further files
4135providing the x509 certificates. The certificates must be stored
4136in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
4137@var{server-cert.pem} (only servers), @var{server-key.pem} (only servers),
4138@var{client-cert.pem} (only clients), and @var{client-key.pem} (only clients).
4139
4140For the @var{server-key.pem} and @var{client-key.pem} files which
4141contain sensitive private keys, it is possible to use an encrypted
4142version by providing the @var{passwordid} parameter. This provides
4143the ID of a previously created @code{secret} object containing the
4144password for decryption.
4145
4146The @var{priority} parameter allows to override the global default
4147priority used by gnutls. This can be useful if the system administrator
4148needs to use a weaker set of crypto priorities for QEMU without
4149potentially forcing the weakness onto all applications. Or conversely
4150if one wants wants a stronger default for QEMU than for all other
4151applications, they can do this through this parameter. Its format is
4152a gnutls priority string as described at
4153@url{https://gnutls.org/manual/html_node/Priority-Strings.html}.
4154
4155@item -object filter-buffer,id=@var{id},netdev=@var{netdevid},interval=@var{t}[,queue=@var{all|rx|tx}][,status=@var{on|off}]
4156
4157Interval @var{t} can't be 0, this filter batches the packet delivery: all
4158packets arriving in a given interval on netdev @var{netdevid} are delayed
4159until the end of the interval. Interval is in microseconds.
4160@option{status} is optional that indicate whether the netfilter is
4161on (enabled) or off (disabled), the default status for netfilter will be 'on'.
4162
4163queue @var{all|rx|tx} is an option that can be applied to any netfilter.
4164
4165@option{all}: the filter is attached both to the receive and the transmit
4166              queue of the netdev (default).
4167
4168@option{rx}: the filter is attached to the receive queue of the netdev,
4169             where it will receive packets sent to the netdev.
4170
4171@option{tx}: the filter is attached to the transmit queue of the netdev,
4172             where it will receive packets sent by the netdev.
4173
4174@item -object filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4175
4176filter-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.
4177
4178@item -object filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},outdev=@var{chardevid},queue=@var{all|rx|tx}[,vnet_hdr_support]
4179
4180filter-redirector on netdev @var{netdevid},redirect filter's net packet to chardev
4181@var{chardevid},and redirect indev's packet to filter.if it has the vnet_hdr_support flag,
4182filter-redirector will redirect packet with vnet_hdr_len.
4183Create a filter-redirector we need to differ outdev id from indev id, id can not
4184be the same. we can just use indev or outdev, but at least one of indev or outdev
4185need to be specified.
4186
4187@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},queue=@var{all|rx|tx},[vnet_hdr_support]
4188
4189Filter-rewriter is a part of COLO project.It will rewrite tcp packet to
4190secondary from primary to keep secondary tcp connection,and rewrite
4191tcp packet to primary from secondary make tcp packet can be handled by
4192client.if it has the vnet_hdr_support flag, we can parse packet with vnet header.
4193
4194usage:
4195colo secondary:
4196-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4197-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4198-object filter-rewriter,id=rew0,netdev=hn0,queue=all
4199
4200@item -object filter-dump,id=@var{id},netdev=@var{dev}[,file=@var{filename}][,maxlen=@var{len}]
4201
4202Dump the network traffic on netdev @var{dev} to the file specified by
4203@var{filename}. At most @var{len} bytes (64k by default) per packet are stored.
4204The file format is libpcap, so it can be analyzed with tools such as tcpdump
4205or Wireshark.
4206
4207@item -object colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},outdev=@var{chardevid}[,vnet_hdr_support]
4208
4209Colo-compare gets packet from primary_in@var{chardevid} and secondary_in@var{chardevid}, than compare primary packet with
4210secondary packet. If the packets are same, we will output primary
4211packet to outdev@var{chardevid}, else we will notify colo-frame
4212do checkpoint and send primary packet to outdev@var{chardevid}.
4213if it has the vnet_hdr_support flag, colo compare will send/recv packet with vnet_hdr_len.
4214
4215we must use it with the help of filter-mirror and filter-redirector.
4216
4217@example
4218
4219primary:
4220-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
4221-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
4222-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
4223-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
4224-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
4225-chardev socket,id=compare0-0,host=3.3.3.3,port=9001
4226-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
4227-chardev socket,id=compare_out0,host=3.3.3.3,port=9005
4228-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
4229-object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
4230-object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
4231-object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
4232
4233secondary:
4234-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown
4235-device e1000,netdev=hn0,mac=52:a4:00:12:78:66
4236-chardev socket,id=red0,host=3.3.3.3,port=9003
4237-chardev socket,id=red1,host=3.3.3.3,port=9004
4238-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
4239-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
4240
4241@end example
4242
4243If you want to know the detail of above command line, you can read
4244the colo-compare git log.
4245
4246@item -object cryptodev-backend-builtin,id=@var{id}[,queues=@var{queues}]
4247
4248Creates a cryptodev backend which executes crypto opreation from
4249the QEMU cipher APIS. The @var{id} parameter is
4250a unique ID that will be used to reference this cryptodev backend from
4251the @option{virtio-crypto} device. The @var{queues} parameter is optional,
4252which specify the queue number of cryptodev backend, the default of
4253@var{queues} is 1.
4254
4255@example
4256
4257 # qemu-system-x86_64 \
4258   [...] \
4259       -object cryptodev-backend-builtin,id=cryptodev0 \
4260       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4261   [...]
4262@end example
4263
4264@item -object cryptodev-vhost-user,id=@var{id},chardev=@var{chardevid}[,queues=@var{queues}]
4265
4266Creates a vhost-user cryptodev backend, backed by a chardev @var{chardevid}.
4267The @var{id} parameter is a unique ID that will be used to reference this
4268cryptodev backend from the @option{virtio-crypto} device.
4269The chardev should be a unix domain socket backed one. The vhost-user uses
4270a specifically defined protocol to pass vhost ioctl replacement messages
4271to an application on the other end of the socket.
4272The @var{queues} parameter is optional, which specify the queue number
4273of cryptodev backend for multiqueue vhost-user, the default of @var{queues} is 1.
4274
4275@example
4276
4277 # qemu-system-x86_64 \
4278   [...] \
4279       -chardev socket,id=chardev0,path=/path/to/socket \
4280       -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \
4281       -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \
4282   [...]
4283@end example
4284
4285@item -object secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4286@item -object secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
4287
4288Defines a secret to store a password, encryption key, or some other sensitive
4289data. The sensitive data can either be passed directly via the @var{data}
4290parameter, or indirectly via the @var{file} parameter. Using the @var{data}
4291parameter is insecure unless the sensitive data is encrypted.
4292
4293The sensitive data can be provided in raw format (the default), or base64.
4294When encoded as JSON, the raw format only supports valid UTF-8 characters,
4295so base64 is recommended for sending binary data. QEMU will convert from
4296which ever format is provided to the format it needs internally. eg, an
4297RBD password can be provided in raw format, even though it will be base64
4298encoded when passed onto the RBD sever.
4299
4300For added protection, it is possible to encrypt the data associated with
4301a secret using the AES-256-CBC cipher. Use of encryption is indicated
4302by providing the @var{keyid} and @var{iv} parameters. The @var{keyid}
4303parameter provides the ID of a previously defined secret that contains
4304the AES-256 decryption key. This key should be 32-bytes long and be
4305base64 encoded. The @var{iv} parameter provides the random initialization
4306vector used for encryption of this particular secret and should be a
4307base64 encrypted string of the 16-byte IV.
4308
4309The simplest (insecure) usage is to provide the secret inline
4310
4311@example
4312
4313 # $QEMU -object secret,id=sec0,data=letmein,format=raw
4314
4315@end example
4316
4317The simplest secure usage is to provide the secret via a file
4318
4319 # printf "letmein" > mypasswd.txt
4320 # $QEMU -object secret,id=sec0,file=mypasswd.txt,format=raw
4321
4322For greater security, AES-256-CBC should be used. To illustrate usage,
4323consider the openssl command line tool which can encrypt the data. Note
4324that when encrypting, the plaintext must be padded to the cipher block
4325size (32 bytes) using the standard PKCS#5/6 compatible padding algorithm.
4326
4327First a master key needs to be created in base64 encoding:
4328
4329@example
4330 # openssl rand -base64 32 > key.b64
4331 # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
4332@end example
4333
4334Each secret to be encrypted needs to have a random initialization vector
4335generated. These do not need to be kept secret
4336
4337@example
4338 # openssl rand -base64 16 > iv.b64
4339 # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
4340@end example
4341
4342The secret to be defined can now be encrypted, in this case we're
4343telling openssl to base64 encode the result, but it could be left
4344as raw bytes if desired.
4345
4346@example
4347 # SECRET=$(printf "letmein" |
4348            openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
4349@end example
4350
4351When launching QEMU, create a master secret pointing to @code{key.b64}
4352and specify that to be used to decrypt the user password. Pass the
4353contents of @code{iv.b64} to the second secret
4354
4355@example
4356 # $QEMU \
4357     -object secret,id=secmaster0,format=base64,file=key.b64 \
4358     -object secret,id=sec0,keyid=secmaster0,format=base64,\
4359         data=$SECRET,iv=$(<iv.b64)
4360@end example
4361
4362@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}]
4363
4364Create a Secure Encrypted Virtualization (SEV) guest object, which can be used
4365to provide the guest memory encryption support on AMD processors.
4366
4367When memory encryption is enabled, one of the physical address bit (aka the
4368C-bit) is utilized to mark if a memory page is protected. The @option{cbitpos}
4369is used to provide the C-bit position. The C-bit position is Host family dependent
4370hence user must provide this value. On EPYC, the value should be 47.
4371
4372When memory encryption is enabled, we loose certain bits in physical address space.
4373The @option{reduced-phys-bits} is used to provide the number of bits we loose in
4374physical address space. Similar to C-bit, the value is Host family dependent.
4375On EPYC, the value should be 5.
4376
4377The @option{sev-device} provides the device file to use for communicating with
4378the SEV firmware running inside AMD Secure Processor. The default device is
4379'/dev/sev'. If hardware supports memory encryption then /dev/sev devices are
4380created by CCP driver.
4381
4382The @option{policy} provides the guest policy to be enforced by the SEV firmware
4383and restrict what configuration and operational commands can be performed on this
4384guest by the hypervisor. The policy should be provided by the guest owner and is
4385bound to the guest and cannot be changed throughout the lifetime of the guest.
4386The default is 0.
4387
4388If guest @option{policy} allows sharing the key with another SEV guest then
4389@option{handle} can be use to provide handle of the guest from which to share
4390the key.
4391
4392The @option{dh-cert-file} and @option{session-file} provides the guest owner's
4393Public Diffie-Hillman key defined in SEV spec. The PDH and session parameters
4394are used for establishing a cryptographic session with the guest owner to
4395negotiate keys used for attestation. The file must be encoded in base64.
4396
4397e.g to launch a SEV guest
4398@example
4399 # $QEMU \
4400     ......
4401     -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
4402     -machine ...,memory-encryption=sev0
4403     .....
4404
4405@end example
4406@end table
4407
4408ETEXI
4409
4410
4411HXCOMM This is the last statement. Insert new options before this line!
4412STEXI
4413@end table
4414ETEXI
4415