1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST 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 rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hax, hvf, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " enforce-config-section=on|off enforce configuration section migration (default=off)\n" 38 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 39 " hmat=on|off controls ACPI HMAT support (default=off)\n", 40 QEMU_ARCH_ALL) 41SRST 42``-machine [type=]name[,prop=value[,...]]`` 43 Select the emulated machine by name. Use ``-machine help`` to list 44 available machines. 45 46 For architectures which aim to support live migration compatibility 47 across releases, each release will introduce a new versioned machine 48 type. For example, the 2.8.0 release introduced machine types 49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 50 51 To allow live migration of guests from QEMU version 2.8.0, to QEMU 52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 54 skip multiple intermediate releases when upgrading, new releases of 55 QEMU will support machine types from many previous versions. 56 57 Supported machine properties are: 58 59 ``accel=accels1[:accels2[:...]]`` 60 This is used to enable an accelerator. Depending on the target 61 architecture, kvm, xen, hax, hvf, whpx or tcg can be available. 62 By default, tcg is used. If there is more than one accelerator 63 specified, the next one is used if the previous one fails to 64 initialize. 65 66 ``vmport=on|off|auto`` 67 Enables emulation of VMWare IO port, for vmmouse etc. auto says 68 to select the value based on accel. For accel=xen the default is 69 off otherwise the default is on. 70 71 ``dump-guest-core=on|off`` 72 Include guest memory in a core dump. The default is on. 73 74 ``mem-merge=on|off`` 75 Enables or disables memory merge support. This feature, when 76 supported by the host, de-duplicates identical memory pages 77 among VMs instances (enabled by default). 78 79 ``aes-key-wrap=on|off`` 80 Enables or disables AES key wrapping support on s390-ccw hosts. 81 This feature controls whether AES wrapping keys will be created 82 to allow execution of AES cryptographic functions. The default 83 is on. 84 85 ``dea-key-wrap=on|off`` 86 Enables or disables DEA key wrapping support on s390-ccw hosts. 87 This feature controls whether DEA wrapping keys will be created 88 to allow execution of DEA cryptographic functions. The default 89 is on. 90 91 ``nvdimm=on|off`` 92 Enables or disables NVDIMM support. The default is off. 93 94 ``enforce-config-section=on|off`` 95 If ``enforce-config-section`` is set to on, force migration code 96 to send configuration section even if the machine-type sets the 97 ``migration.send-configuration`` property to off. NOTE: this 98 parameter is deprecated. Please use ``-global`` 99 ``migration.send-configuration``\ =on\|off instead. 100 101 ``memory-encryption=`` 102 Memory encryption object to use. The default is none. 103 104 ``hmat=on|off`` 105 Enables or disables ACPI Heterogeneous Memory Attribute Table 106 (HMAT) support. The default is off. 107ERST 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) 114SRST 115``-cpu model`` 116 Select CPU model (``-cpu help`` for list and additional feature 117 selection) 118ERST 119 120DEF("accel", HAS_ARG, QEMU_OPTION_accel, 121 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 122 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n" 123 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 124 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 125 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 126 " tb-size=n (TCG translation block cache size)\n" 127 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 128SRST 129``-accel name[,prop=value[,...]]`` 130 This is used to enable an accelerator. Depending on the target 131 architecture, kvm, xen, hax, hvf, whpx or tcg can be available. By 132 default, tcg is used. If there is more than one accelerator 133 specified, the next one is used if the previous one fails to 134 initialize. 135 136 ``igd-passthru=on|off`` 137 When Xen is in use, this option controls whether Intel 138 integrated graphics devices can be passed through to the guest 139 (default=off) 140 141 ``kernel-irqchip=on|off|split`` 142 Controls KVM in-kernel irqchip support. The default is full 143 acceleration of the interrupt controllers. On x86, split irqchip 144 reduces the kernel attack surface, at a performance cost for 145 non-MSI interrupts. Disabling the in-kernel irqchip completely 146 is not recommended except for debugging purposes. 147 148 ``kvm-shadow-mem=size`` 149 Defines the size of the KVM shadow MMU. 150 151 ``tb-size=n`` 152 Controls the size (in MiB) of the TCG translation block cache. 153 154 ``thread=single|multi`` 155 Controls number of TCG threads. When the TCG is multi-threaded 156 there will be one thread per vCPU therefor taking advantage of 157 additional host cores. The default is to enable multi-threading 158 where both the back-end and front-ends support it and no 159 incompatible TCG features have been enabled (e.g. 160 icount/replay). 161ERST 162 163DEF("smp", HAS_ARG, QEMU_OPTION_smp, 164 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 165 " set the number of CPUs to 'n' [default=1]\n" 166 " maxcpus= maximum number of total cpus, including\n" 167 " offline CPUs for hotplug, etc\n" 168 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 169 " threads= number of threads on one CPU core\n" 170 " dies= number of CPU dies on one socket (for PC only)\n" 171 " sockets= number of discrete sockets in the system\n", 172 QEMU_ARCH_ALL) 173SRST 174``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 175 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 176 are supported. On Sparc32 target, Linux limits the number of usable 177 CPUs to 4. For the PC target, the number of cores per die, the 178 number of threads per cores, the number of dies per packages and the 179 total number of sockets can be specified. Missing values will be 180 computed. If any on the three values is given, the total number of 181 CPUs n can be omitted. maxcpus specifies the maximum number of 182 hotpluggable CPUs. 183ERST 184 185DEF("numa", HAS_ARG, QEMU_OPTION_numa, 186 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 187 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 188 "-numa dist,src=source,dst=destination,val=distance\n" 189 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 190 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 191 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 192 QEMU_ARCH_ALL) 193SRST 194``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 195 \ 196``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 197 \ 198``-numa dist,src=source,dst=destination,val=distance`` 199 \ 200``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 201 \ 202``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 203 \ 204``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 205 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 206 distance from a source node to a destination node. Set the ACPI 207 Heterogeneous Memory Attributes for the given nodes. 208 209 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 210 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 211 contiguous range of CPU indexes (or a single VCPU if lastcpu is 212 omitted). A non-contiguous set of VCPUs can be represented by 213 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 214 omitted on all nodes, VCPUs are automatically split between them. 215 216 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 217 NUMA node: 218 219 :: 220 221 -numa node,cpus=0-2,cpus=5 222 223 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 224 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 225 assign CPU objects to a node using topology layout properties of 226 CPU. The set of properties is machine specific, and depends on used 227 machine type/'\ ``smp``\ ' options. It could be queried with 228 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 229 property specifies node to which CPU object will be assigned, it's 230 required for node to be declared with '\ ``node``\ ' option before 231 it's used with '\ ``cpu``\ ' option. 232 233 For example: 234 235 :: 236 237 -M pc \ 238 -smp 1,sockets=2,maxcpus=2 \ 239 -numa node,nodeid=0 -numa node,nodeid=1 \ 240 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 241 242 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 243 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 244 a given memory backend device to a node. If '\ ``mem``\ ' and 245 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 246 247 248 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 249 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 250 use it. 251 252 '\ ``initiator``\ ' is an additional option that points to an 253 initiator NUMA node that has best performance (the lowest latency or 254 largest bandwidth) to this NUMA node. Note that this option can be 255 set only when the machine property 'hmat' is set to 'on'. 256 257 Following example creates a machine with 2 NUMA nodes, node 0 has 258 CPU. node 1 has only memory, and its initiator is node 0. Note that 259 because node 0 has CPU, by default the initiator of node 0 is itself 260 and must be itself. 261 262 :: 263 264 -machine hmat=on \ 265 -m 2G,slots=2,maxmem=4G \ 266 -object memory-backend-ram,size=1G,id=m0 \ 267 -object memory-backend-ram,size=1G,id=m1 \ 268 -numa node,nodeid=0,memdev=m0 \ 269 -numa node,nodeid=1,memdev=m1,initiator=0 \ 270 -smp 2,sockets=2,maxcpus=2 \ 271 -numa cpu,node-id=0,socket-id=0 \ 272 -numa cpu,node-id=0,socket-id=1 273 274 source and destination are NUMA node IDs. distance is the NUMA 275 distance from source to destination. The distance from a node to 276 itself is always 10. If any pair of nodes is given a distance, then 277 all pairs must be given distances. Although, when distances are only 278 given in one direction for each pair of nodes, then the distances in 279 the opposite directions are assumed to be the same. If, however, an 280 asymmetrical pair of distances is given for even one node pair, then 281 all node pairs must be provided distance values for both directions, 282 even when they are symmetrical. When a node is unreachable from 283 another node, set the pair's distance to 255. 284 285 Note that the -``numa`` option doesn't allocate any of the specified 286 resources, it just assigns existing resources to NUMA nodes. This 287 means that one still has to use the ``-m``, ``-smp`` options to 288 allocate RAM and VCPUs respectively. 289 290 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 291 Information between initiator and target NUMA nodes in ACPI 292 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 293 create memory requests, usually it has one or more processors. 294 Target NUMA node contains addressable memory. 295 296 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 297 the memory hierarchy of the target NUMA node: if hierarchy is 298 'memory', the structure represents the memory performance; if 299 hierarchy is 'first-level\|second-level\|third-level', this 300 structure represents aggregated performance of memory side caches 301 for each domain. type of 'data-type' is type of data represented by 302 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 303 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 304 the target memory; if 'hierarchy' is 305 'first-level\|second-level\|third-level', 'data-type' is 306 'access\|read\|write' hit latency or 'access\|read\|write' hit 307 bandwidth of the target memory side cache. 308 309 lat is latency value in nanoseconds. bw is bandwidth value, the 310 possible value and units are NUM[M\|G\|T], mean that the bandwidth 311 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 312 used suffix). Note that if latency or bandwidth value is 0, means 313 the corresponding latency or bandwidth information is not provided. 314 315 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 316 belongs. size is the size of memory side cache in bytes. level is 317 the cache level described in this structure, note that the cache 318 level 0 should not be used with '\ ``hmat-cache``\ ' option. 319 associativity is the cache associativity, the possible value is 320 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 321 is the write policy. line is the cache Line size in bytes. 322 323 For example, the following options describe 2 NUMA nodes. Node 0 has 324 2 cpus and a ram, node 1 has only a ram. The processors in node 0 325 access memory in node 0 with access-latency 5 nanoseconds, 326 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 327 memory in NUMA node 1 with access-latency 10 nanoseconds, 328 access-bandwidth is 100 MB/s. And for memory side cache information, 329 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 330 policy is write-back, the cache Line size is 8 bytes: 331 332 :: 333 334 -machine hmat=on \ 335 -m 2G \ 336 -object memory-backend-ram,size=1G,id=m0 \ 337 -object memory-backend-ram,size=1G,id=m1 \ 338 -smp 2 \ 339 -numa node,nodeid=0,memdev=m0 \ 340 -numa node,nodeid=1,memdev=m1,initiator=0 \ 341 -numa cpu,node-id=0,socket-id=0 \ 342 -numa cpu,node-id=0,socket-id=1 \ 343 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 344 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 345 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 346 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 347 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 348 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 349ERST 350 351DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 352 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 353 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 354SRST 355``-add-fd fd=fd,set=set[,opaque=opaque]`` 356 Add a file descriptor to an fd set. Valid options are: 357 358 ``fd=fd`` 359 This option defines the file descriptor of which a duplicate is 360 added to fd set. The file descriptor cannot be stdin, stdout, or 361 stderr. 362 363 ``set=set`` 364 This option defines the ID of the fd set to add the file 365 descriptor to. 366 367 ``opaque=opaque`` 368 This option defines a free-form string that can be used to 369 describe fd. 370 371 You can open an image using pre-opened file descriptors from an fd 372 set: 373 374 .. parsed-literal:: 375 376 |qemu_system| \ 377 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \ 378 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \ 379 -drive file=/dev/fdset/2,index=0,media=disk 380ERST 381 382DEF("set", HAS_ARG, QEMU_OPTION_set, 383 "-set group.id.arg=value\n" 384 " set <arg> parameter for item <id> of type <group>\n" 385 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 386SRST 387``-set group.id.arg=value`` 388 Set parameter arg for item id of type group 389ERST 390 391DEF("global", HAS_ARG, QEMU_OPTION_global, 392 "-global driver.property=value\n" 393 "-global driver=driver,property=property,value=value\n" 394 " set a global default for a driver property\n", 395 QEMU_ARCH_ALL) 396SRST 397``-global driver.prop=value`` 398 \ 399``-global driver=driver,property=property,value=value`` 400 Set default value of driver's property prop to value, e.g.: 401 402 .. parsed-literal:: 403 404 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 405 406 In particular, you can use this to set driver properties for devices 407 which are created automatically by the machine model. To create a 408 device which is not created automatically and set properties on it, 409 use -``device``. 410 411 -global driver.prop=value is shorthand for -global 412 driver=driver,property=prop,value=value. The longhand syntax works 413 even when driver contains a dot. 414ERST 415 416DEF("boot", HAS_ARG, QEMU_OPTION_boot, 417 "-boot [order=drives][,once=drives][,menu=on|off]\n" 418 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 419 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 420 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 421 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 422 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 423 QEMU_ARCH_ALL) 424SRST 425``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 426 Specify boot order drives as a string of drive letters. Valid drive 427 letters depend on the target architecture. The x86 PC uses: a, b 428 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 429 (Etherboot from network adapter 1-4), hard disk boot is the default. 430 To apply a particular boot order only on the first startup, specify 431 it via ``once``. Note that the ``order`` or ``once`` parameter 432 should not be used together with the ``bootindex`` property of 433 devices, since the firmware implementations normally do not support 434 both at the same time. 435 436 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 437 as firmware/BIOS supports them. The default is non-interactive boot. 438 439 A splash picture could be passed to bios, enabling user to show it 440 as logo, when option splash=sp\_name is given and menu=on, If 441 firmware/BIOS supports them. Currently Seabios for X86 system 442 support it. limitation: The splash file could be a jpeg file or a 443 BMP file in 24 BPP format(true color). The resolution should be 444 supported by the SVGA mode, so the recommended is 320x240, 640x480, 445 800x640. 446 447 A timeout could be passed to bios, guest will pause for rb\_timeout 448 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 449 not reboot, qemu passes '-1' to bios by default. Currently Seabios 450 for X86 system support it. 451 452 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 453 it. This only effects when boot priority is changed by bootindex 454 options. The default is non-strict boot. 455 456 .. parsed-literal:: 457 458 # try to boot from network first, then from hard disk 459 |qemu_system_x86| -boot order=nc 460 # boot from CD-ROM first, switch back to default order after reboot 461 |qemu_system_x86| -boot once=d 462 # boot with a splash picture for 5 seconds. 463 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 464 465 Note: The legacy format '-boot drives' is still supported but its 466 use is discouraged as it may be removed from future versions. 467ERST 468 469DEF("m", HAS_ARG, QEMU_OPTION_m, 470 "-m [size=]megs[,slots=n,maxmem=size]\n" 471 " configure guest RAM\n" 472 " size: initial amount of guest memory\n" 473 " slots: number of hotplug slots (default: none)\n" 474 " maxmem: maximum amount of guest memory (default: none)\n" 475 "NOTE: Some architectures might enforce a specific granularity\n", 476 QEMU_ARCH_ALL) 477SRST 478``-m [size=]megs[,slots=n,maxmem=size]`` 479 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 480 Optionally, a suffix of "M" or "G" can be used to signify a value in 481 megabytes or gigabytes respectively. Optional pair slots, maxmem 482 could be used to set amount of hotpluggable memory slots and maximum 483 amount of memory. Note that maxmem must be aligned to the page size. 484 485 For example, the following command-line sets the guest startup RAM 486 size to 1GB, creates 3 slots to hotplug additional memory and sets 487 the maximum memory the guest can reach to 4GB: 488 489 .. parsed-literal:: 490 491 |qemu_system| -m 1G,slots=3,maxmem=4G 492 493 If slots and maxmem are not specified, memory hotplug won't be 494 enabled and the guest startup RAM will never increase. 495ERST 496 497DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 498 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 499SRST 500``-mem-path path`` 501 Allocate guest RAM from a temporarily created file in path. 502ERST 503 504DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 505 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 506 QEMU_ARCH_ALL) 507SRST 508``-mem-prealloc`` 509 Preallocate memory when using -mem-path. 510ERST 511 512DEF("k", HAS_ARG, QEMU_OPTION_k, 513 "-k language use keyboard layout (for example 'fr' for French)\n", 514 QEMU_ARCH_ALL) 515SRST 516``-k language`` 517 Use keyboard layout language (for example ``fr`` for French). This 518 option is only needed where it is not easy to get raw PC keycodes 519 (e.g. on Macs, with some X11 servers or with a VNC or curses 520 display). You don't normally need to use it on PC/Linux or 521 PC/Windows hosts. 522 523 The available layouts are: 524 525 :: 526 527 ar de-ch es fo fr-ca hu ja mk no pt-br sv 528 da en-gb et fr fr-ch is lt nl pl ru th 529 de en-us fi fr-be hr it lv nl-be pt sl tr 530 531 The default is ``en-us``. 532ERST 533 534 535HXCOMM Deprecated by -audiodev 536DEF("audio-help", 0, QEMU_OPTION_audio_help, 537 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 538 QEMU_ARCH_ALL) 539SRST 540``-audio-help`` 541 Will show the -audiodev equivalent of the currently specified 542 (deprecated) environment variables. 543ERST 544 545DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 546 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 547 " specifies the audio backend to use\n" 548 " id= identifier of the backend\n" 549 " timer-period= timer period in microseconds\n" 550 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 551 " in|out.fixed-settings= use fixed settings for host audio\n" 552 " in|out.frequency= frequency to use with fixed settings\n" 553 " in|out.channels= number of channels to use with fixed settings\n" 554 " in|out.format= sample format to use with fixed settings\n" 555 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 556 " in|out.voices= number of voices to use\n" 557 " in|out.buffer-length= length of buffer in microseconds\n" 558 "-audiodev none,id=id,[,prop[=value][,...]]\n" 559 " dummy driver that discards all output\n" 560#ifdef CONFIG_AUDIO_ALSA 561 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 562 " in|out.dev= name of the audio device to use\n" 563 " in|out.period-length= length of period in microseconds\n" 564 " in|out.try-poll= attempt to use poll mode\n" 565 " threshold= threshold (in microseconds) when playback starts\n" 566#endif 567#ifdef CONFIG_AUDIO_COREAUDIO 568 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 569 " in|out.buffer-count= number of buffers\n" 570#endif 571#ifdef CONFIG_AUDIO_DSOUND 572 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 573 " latency= add extra latency to playback in microseconds\n" 574#endif 575#ifdef CONFIG_AUDIO_OSS 576 "-audiodev oss,id=id[,prop[=value][,...]]\n" 577 " in|out.dev= path of the audio device to use\n" 578 " in|out.buffer-count= number of buffers\n" 579 " in|out.try-poll= attempt to use poll mode\n" 580 " try-mmap= try using memory mapped access\n" 581 " exclusive= open device in exclusive mode\n" 582 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 583#endif 584#ifdef CONFIG_AUDIO_PA 585 "-audiodev pa,id=id[,prop[=value][,...]]\n" 586 " server= PulseAudio server address\n" 587 " in|out.name= source/sink device name\n" 588 " in|out.latency= desired latency in microseconds\n" 589#endif 590#ifdef CONFIG_AUDIO_SDL 591 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 592#endif 593#ifdef CONFIG_SPICE 594 "-audiodev spice,id=id[,prop[=value][,...]]\n" 595#endif 596 "-audiodev wav,id=id[,prop[=value][,...]]\n" 597 " path= path of wav file to record\n", 598 QEMU_ARCH_ALL) 599SRST 600``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 601 Adds a new audio backend driver identified by id. There are global 602 and driver specific properties. Some values can be set differently 603 for input and output, they're marked with ``in|out.``. You can set 604 the input's property with ``in.prop`` and the output's property with 605 ``out.prop``. For example: 606 607 :: 608 609 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 610 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 611 612 NOTE: parameter validation is known to be incomplete, in many cases 613 specifying an invalid option causes QEMU to print an error message 614 and continue emulation without sound. 615 616 Valid global options are: 617 618 ``id=identifier`` 619 Identifies the audio backend. 620 621 ``timer-period=period`` 622 Sets the timer period used by the audio subsystem in 623 microseconds. Default is 10000 (10 ms). 624 625 ``in|out.mixing-engine=on|off`` 626 Use QEMU's mixing engine to mix all streams inside QEMU and 627 convert audio formats when not supported by the backend. When 628 off, fixed-settings must be off too. Note that disabling this 629 option means that the selected backend must support multiple 630 streams and the audio formats used by the virtual cards, 631 otherwise you'll get no sound. It's not recommended to disable 632 this option unless you want to use 5.1 or 7.1 audio, as mixing 633 engine only supports mono and stereo audio. Default is on. 634 635 ``in|out.fixed-settings=on|off`` 636 Use fixed settings for host audio. When off, it will change 637 based on how the guest opens the sound card. In this case you 638 must not specify frequency, channels or format. Default is on. 639 640 ``in|out.frequency=frequency`` 641 Specify the frequency to use when using fixed-settings. Default 642 is 44100Hz. 643 644 ``in|out.channels=channels`` 645 Specify the number of channels to use when using fixed-settings. 646 Default is 2 (stereo). 647 648 ``in|out.format=format`` 649 Specify the sample format to use when using fixed-settings. 650 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 651 ``u32``, ``f32``. Default is ``s16``. 652 653 ``in|out.voices=voices`` 654 Specify the number of voices to use. Default is 1. 655 656 ``in|out.buffer-length=usecs`` 657 Sets the size of the buffer in microseconds. 658 659``-audiodev none,id=id[,prop[=value][,...]]`` 660 Creates a dummy backend that discards all outputs. This backend has 661 no backend specific properties. 662 663``-audiodev alsa,id=id[,prop[=value][,...]]`` 664 Creates backend using the ALSA. This backend is only available on 665 Linux. 666 667 ALSA specific options are: 668 669 ``in|out.dev=device`` 670 Specify the ALSA device to use for input and/or output. Default 671 is ``default``. 672 673 ``in|out.period-length=usecs`` 674 Sets the period length in microseconds. 675 676 ``in|out.try-poll=on|off`` 677 Attempt to use poll mode with the device. Default is on. 678 679 ``threshold=threshold`` 680 Threshold (in microseconds) when playback starts. Default is 0. 681 682``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 683 Creates a backend using Apple's Core Audio. This backend is only 684 available on Mac OS and only supports playback. 685 686 Core Audio specific options are: 687 688 ``in|out.buffer-count=count`` 689 Sets the count of the buffers. 690 691``-audiodev dsound,id=id[,prop[=value][,...]]`` 692 Creates a backend using Microsoft's DirectSound. This backend is 693 only available on Windows and only supports playback. 694 695 DirectSound specific options are: 696 697 ``latency=usecs`` 698 Add extra usecs microseconds latency to playback. Default is 699 10000 (10 ms). 700 701``-audiodev oss,id=id[,prop[=value][,...]]`` 702 Creates a backend using OSS. This backend is available on most 703 Unix-like systems. 704 705 OSS specific options are: 706 707 ``in|out.dev=device`` 708 Specify the file name of the OSS device to use. Default is 709 ``/dev/dsp``. 710 711 ``in|out.buffer-count=count`` 712 Sets the count of the buffers. 713 714 ``in|out.try-poll=on|of`` 715 Attempt to use poll mode with the device. Default is on. 716 717 ``try-mmap=on|off`` 718 Try using memory mapped device access. Default is off. 719 720 ``exclusive=on|off`` 721 Open the device in exclusive mode (vmix won't work in this 722 case). Default is off. 723 724 ``dsp-policy=policy`` 725 Sets the timing policy (between 0 and 10, where smaller number 726 means smaller latency but higher CPU usage). Use -1 to use 727 buffer sizes specified by ``buffer`` and ``buffer-count``. This 728 option is ignored if you do not have OSS 4. Default is 5. 729 730``-audiodev pa,id=id[,prop[=value][,...]]`` 731 Creates a backend using PulseAudio. This backend is available on 732 most systems. 733 734 PulseAudio specific options are: 735 736 ``server=server`` 737 Sets the PulseAudio server to connect to. 738 739 ``in|out.name=sink`` 740 Use the specified source/sink for recording/playback. 741 742 ``in|out.latency=usecs`` 743 Desired latency in microseconds. The PulseAudio server will try 744 to honor this value but actual latencies may be lower or higher. 745 746``-audiodev sdl,id=id[,prop[=value][,...]]`` 747 Creates a backend using SDL. This backend is available on most 748 systems, but you should use your platform's native backend if 749 possible. This backend has no backend specific properties. 750 751``-audiodev spice,id=id[,prop[=value][,...]]`` 752 Creates a backend that sends audio through SPICE. This backend 753 requires ``-spice`` and automatically selected in that case, so 754 usually you can ignore this option. This backend has no backend 755 specific properties. 756 757``-audiodev wav,id=id[,prop[=value][,...]]`` 758 Creates a backend that writes audio to a WAV file. 759 760 Backend specific options are: 761 762 ``path=path`` 763 Write recorded audio into the specified file. Default is 764 ``qemu.wav``. 765ERST 766 767DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 768 "-soundhw c1,... enable audio support\n" 769 " and only specified sound cards (comma separated list)\n" 770 " use '-soundhw help' to get the list of supported cards\n" 771 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 772SRST 773``-soundhw card1[,card2,...] or -soundhw all`` 774 Enable audio and selected sound hardware. Use 'help' to print all 775 available sound hardware. For example: 776 777 .. parsed-literal:: 778 779 |qemu_system_x86| -soundhw sb16,adlib disk.img 780 |qemu_system_x86| -soundhw es1370 disk.img 781 |qemu_system_x86| -soundhw ac97 disk.img 782 |qemu_system_x86| -soundhw hda disk.img 783 |qemu_system_x86| -soundhw all disk.img 784 |qemu_system_x86| -soundhw help 785 786 Note that Linux's i810\_audio OSS kernel (for AC97) module might 787 require manually specifying clocking. 788 789 :: 790 791 modprobe i810_audio clocking=48000 792ERST 793 794DEF("device", HAS_ARG, QEMU_OPTION_device, 795 "-device driver[,prop[=value][,...]]\n" 796 " add device (based on driver)\n" 797 " prop=value,... sets driver properties\n" 798 " use '-device help' to print all possible drivers\n" 799 " use '-device driver,help' to print all possible properties\n", 800 QEMU_ARCH_ALL) 801SRST 802``-device driver[,prop[=value][,...]]`` 803 Add device driver. prop=value sets driver properties. Valid 804 properties depend on the driver. To get help on possible drivers and 805 properties, use ``-device help`` and ``-device driver,help``. 806 807 Some drivers are: 808 809``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 810 Add an IPMI BMC. This is a simulation of a hardware management 811 interface processor that normally sits on a system. It provides a 812 watchdog and the ability to reset and power control the system. You 813 need to connect this to an IPMI interface to make it useful 814 815 The IPMI slave address to use for the BMC. The default is 0x20. This 816 address is the BMC's address on the I2C network of management 817 controllers. If you don't know what this means, it is safe to ignore 818 it. 819 820 ``id=id`` 821 The BMC id for interfaces to use this device. 822 823 ``slave_addr=val`` 824 Define slave address to use for the BMC. The default is 0x20. 825 826 ``sdrfile=file`` 827 file containing raw Sensor Data Records (SDR) data. The default 828 is none. 829 830 ``fruareasize=val`` 831 size of a Field Replaceable Unit (FRU) area. The default is 832 1024. 833 834 ``frudatafile=file`` 835 file containing raw Field Replaceable Unit (FRU) inventory data. 836 The default is none. 837 838 ``guid=uuid`` 839 value for the GUID for the BMC, in standard UUID format. If this 840 is set, get "Get GUID" command to the BMC will return it. 841 Otherwise "Get GUID" will return an error. 842 843``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 844 Add a connection to an external IPMI BMC simulator. Instead of 845 locally emulating the BMC like the above item, instead connect to an 846 external entity that provides the IPMI services. 847 848 A connection is made to an external BMC simulator. If you do this, 849 it is strongly recommended that you use the "reconnect=" chardev 850 option to reconnect to the simulator if the connection is lost. Note 851 that if this is not used carefully, it can be a security issue, as 852 the interface has the ability to send resets, NMIs, and power off 853 the VM. It's best if QEMU makes a connection to an external 854 simulator running on a secure port on localhost, so neither the 855 simulator nor QEMU is exposed to any outside network. 856 857 See the "lanserv/README.vm" file in the OpenIPMI library for more 858 details on the external interface. 859 860``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 861 Add a KCS IPMI interafce on the ISA bus. This also adds a 862 corresponding ACPI and SMBIOS entries, if appropriate. 863 864 ``bmc=id`` 865 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 866 above. 867 868 ``ioport=val`` 869 Define the I/O address of the interface. The default is 0xca0 870 for KCS. 871 872 ``irq=val`` 873 Define the interrupt to use. The default is 5. To disable 874 interrupts, set this to 0. 875 876``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 877 Like the KCS interface, but defines a BT interface. The default port 878 is 0xe4 and the default interrupt is 5. 879 880``-device pci-ipmi-kcs,bmc=id`` 881 Add a KCS IPMI interafce on the PCI bus. 882 883 ``bmc=id`` 884 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 885 886``-device pci-ipmi-bt,bmc=id`` 887 Like the KCS interface, but defines a BT interface on the PCI bus. 888ERST 889 890DEF("name", HAS_ARG, QEMU_OPTION_name, 891 "-name string1[,process=string2][,debug-threads=on|off]\n" 892 " set the name of the guest\n" 893 " string1 sets the window title and string2 the process name\n" 894 " When debug-threads is enabled, individual threads are given a separate name\n" 895 " NOTE: The thread names are for debugging and not a stable API.\n", 896 QEMU_ARCH_ALL) 897SRST 898``-name name`` 899 Sets the name of the guest. This name will be displayed in the SDL 900 window caption. The name will also be used for the VNC server. Also 901 optionally set the top visible process name in Linux. Naming of 902 individual threads can also be enabled on Linux to aid debugging. 903ERST 904 905DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 906 "-uuid %08x-%04x-%04x-%04x-%012x\n" 907 " specify machine UUID\n", QEMU_ARCH_ALL) 908SRST 909``-uuid uuid`` 910 Set system UUID. 911ERST 912 913DEFHEADING() 914 915DEFHEADING(Block device options:) 916 917DEF("fda", HAS_ARG, QEMU_OPTION_fda, 918 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 919DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 920SRST 921``-fda file`` 922 \ 923``-fdb file`` 924 Use file as floppy disk 0/1 image (see 925 :ref:`disk_005fimages`). 926ERST 927 928DEF("hda", HAS_ARG, QEMU_OPTION_hda, 929 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 930DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 931DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 932 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 933DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 934SRST 935``-hda file`` 936 \ 937``-hdb file`` 938 \ 939``-hdc file`` 940 \ 941``-hdd file`` 942 Use file as hard disk 0, 1, 2 or 3 image (see 943 :ref:`disk_005fimages`). 944ERST 945 946DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 947 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 948 QEMU_ARCH_ALL) 949SRST 950``-cdrom file`` 951 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 952 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 953 as filename. 954ERST 955 956DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 957 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 958 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 959 " [,read-only=on|off][,auto-read-only=on|off]\n" 960 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 961 " [,driver specific parameters...]\n" 962 " configure a block backend\n", QEMU_ARCH_ALL) 963SRST 964``-blockdev option[,option[,option[,...]]]`` 965 Define a new block driver node. Some of the options apply to all 966 block drivers, other options are only accepted for a specific block 967 driver. See below for a list of generic options and options for the 968 most common block drivers. 969 970 Options that expect a reference to another node (e.g. ``file``) can 971 be given in two ways. Either you specify the node name of an already 972 existing node (file=node-name), or you define a new node inline, 973 adding options for the referenced node after a dot 974 (file.filename=path,file.aio=native). 975 976 A block driver node created with ``-blockdev`` can be used for a 977 guest device by specifying its node name for the ``drive`` property 978 in a ``-device`` argument that defines a block device. 979 980 ``Valid options for any block driver node:`` 981 ``driver`` 982 Specifies the block driver to use for the given node. 983 984 ``node-name`` 985 This defines the name of the block driver node by which it 986 will be referenced later. The name must be unique, i.e. it 987 must not match the name of a different block driver node, or 988 (if you use ``-drive`` as well) the ID of a drive. 989 990 If no node name is specified, it is automatically generated. 991 The generated node name is not intended to be predictable 992 and changes between QEMU invocations. For the top level, an 993 explicit node name must be specified. 994 995 ``read-only`` 996 Open the node read-only. Guest write attempts will fail. 997 998 Note that some block drivers support only read-only access, 999 either generally or in certain configurations. In this case, 1000 the default value ``read-only=off`` does not work and the 1001 option must be specified explicitly. 1002 1003 ``auto-read-only`` 1004 If ``auto-read-only=on`` is set, QEMU may fall back to 1005 read-only usage even when ``read-only=off`` is requested, or 1006 even switch between modes as needed, e.g. depending on 1007 whether the image file is writable or whether a writing user 1008 is attached to the node. 1009 1010 ``force-share`` 1011 Override the image locking system of QEMU by forcing the 1012 node to utilize weaker shared access for permissions where 1013 it would normally request exclusive access. When there is 1014 the potential for multiple instances to have the same file 1015 open (whether this invocation of QEMU is the first or the 1016 second instance), both instances must permit shared access 1017 for the second instance to succeed at opening the file. 1018 1019 Enabling ``force-share=on`` requires ``read-only=on``. 1020 1021 ``cache.direct`` 1022 The host page cache can be avoided with ``cache.direct=on``. 1023 This will attempt to do disk IO directly to the guest's 1024 memory. QEMU may still perform an internal copy of the data. 1025 1026 ``cache.no-flush`` 1027 In case you don't care about data integrity over host 1028 failures, you can use ``cache.no-flush=on``. This option 1029 tells QEMU that it never needs to write any data to the disk 1030 but can instead keep things in cache. If anything goes 1031 wrong, like your host losing power, the disk storage getting 1032 disconnected accidentally, etc. your image will most 1033 probably be rendered unusable. 1034 1035 ``discard=discard`` 1036 discard is one of "ignore" (or "off") or "unmap" (or "on") 1037 and controls whether ``discard`` (also known as ``trim`` or 1038 ``unmap``) requests are ignored or passed to the filesystem. 1039 Some machine types may not support discard requests. 1040 1041 ``detect-zeroes=detect-zeroes`` 1042 detect-zeroes is "off", "on" or "unmap" and enables the 1043 automatic conversion of plain zero writes by the OS to 1044 driver specific optimized zero write commands. You may even 1045 choose "unmap" if discard is set to "unmap" to allow a zero 1046 write to be converted to an ``unmap`` operation. 1047 1048 ``Driver-specific options for file`` 1049 This is the protocol-level block driver for accessing regular 1050 files. 1051 1052 ``filename`` 1053 The path to the image file in the local filesystem 1054 1055 ``aio`` 1056 Specifies the AIO backend (threads/native, default: threads) 1057 1058 ``locking`` 1059 Specifies whether the image file is protected with Linux OFD 1060 / POSIX locks. The default is to use the Linux Open File 1061 Descriptor API if available, otherwise no lock is applied. 1062 (auto/on/off, default: auto) 1063 1064 Example: 1065 1066 :: 1067 1068 -blockdev driver=file,node-name=disk,filename=disk.img 1069 1070 ``Driver-specific options for raw`` 1071 This is the image format block driver for raw images. It is 1072 usually stacked on top of a protocol level block driver such as 1073 ``file``. 1074 1075 ``file`` 1076 Reference to or definition of the data source block driver 1077 node (e.g. a ``file`` driver node) 1078 1079 Example 1: 1080 1081 :: 1082 1083 -blockdev driver=file,node-name=disk_file,filename=disk.img 1084 -blockdev driver=raw,node-name=disk,file=disk_file 1085 1086 Example 2: 1087 1088 :: 1089 1090 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1091 1092 ``Driver-specific options for qcow2`` 1093 This is the image format block driver for qcow2 images. It is 1094 usually stacked on top of a protocol level block driver such as 1095 ``file``. 1096 1097 ``file`` 1098 Reference to or definition of the data source block driver 1099 node (e.g. a ``file`` driver node) 1100 1101 ``backing`` 1102 Reference to or definition of the backing file block device 1103 (default is taken from the image file). It is allowed to 1104 pass ``null`` here in order to disable the default backing 1105 file. 1106 1107 ``lazy-refcounts`` 1108 Whether to enable the lazy refcounts feature (on/off; 1109 default is taken from the image file) 1110 1111 ``cache-size`` 1112 The maximum total size of the L2 table and refcount block 1113 caches in bytes (default: the sum of l2-cache-size and 1114 refcount-cache-size) 1115 1116 ``l2-cache-size`` 1117 The maximum size of the L2 table cache in bytes (default: if 1118 cache-size is not specified - 32M on Linux platforms, and 8M 1119 on non-Linux platforms; otherwise, as large as possible 1120 within the cache-size, while permitting the requested or the 1121 minimal refcount cache size) 1122 1123 ``refcount-cache-size`` 1124 The maximum size of the refcount block cache in bytes 1125 (default: 4 times the cluster size; or if cache-size is 1126 specified, the part of it which is not used for the L2 1127 cache) 1128 1129 ``cache-clean-interval`` 1130 Clean unused entries in the L2 and refcount caches. The 1131 interval is in seconds. The default value is 600 on 1132 supporting platforms, and 0 on other platforms. Setting it 1133 to 0 disables this feature. 1134 1135 ``pass-discard-request`` 1136 Whether discard requests to the qcow2 device should be 1137 forwarded to the data source (on/off; default: on if 1138 discard=unmap is specified, off otherwise) 1139 1140 ``pass-discard-snapshot`` 1141 Whether discard requests for the data source should be 1142 issued when a snapshot operation (e.g. deleting a snapshot) 1143 frees clusters in the qcow2 file (on/off; default: on) 1144 1145 ``pass-discard-other`` 1146 Whether discard requests for the data source should be 1147 issued on other occasions where a cluster gets freed 1148 (on/off; default: off) 1149 1150 ``overlap-check`` 1151 Which overlap checks to perform for writes to the image 1152 (none/constant/cached/all; default: cached). For details or 1153 finer granularity control refer to the QAPI documentation of 1154 ``blockdev-add``. 1155 1156 Example 1: 1157 1158 :: 1159 1160 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1161 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1162 1163 Example 2: 1164 1165 :: 1166 1167 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1168 1169 ``Driver-specific options for other drivers`` 1170 Please refer to the QAPI documentation of the ``blockdev-add`` 1171 QMP command. 1172ERST 1173 1174DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1175 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1176 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1177 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1178 " [,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]\n" 1179 " [,readonly=on|off][,copy-on-read=on|off]\n" 1180 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1181 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1182 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1183 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1184 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1185 " [[,iops_size=is]]\n" 1186 " [[,group=g]]\n" 1187 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1188SRST 1189``-drive option[,option[,option[,...]]]`` 1190 Define a new drive. This includes creating a block driver node (the 1191 backend) as well as a guest device, and is mostly a shortcut for 1192 defining the corresponding ``-blockdev`` and ``-device`` options. 1193 1194 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1195 In addition, it knows the following options: 1196 1197 ``file=file`` 1198 This option defines which disk image (see 1199 :ref:`disk_005fimages`) to use with this drive. If 1200 the filename contains comma, you must double it (for instance, 1201 "file=my,,file" to use file "my,file"). 1202 1203 Special files such as iSCSI devices can be specified using 1204 protocol specific URLs. See the section for "Device URL Syntax" 1205 for more information. 1206 1207 ``if=interface`` 1208 This option defines on which type on interface the drive is 1209 connected. Available types are: ide, scsi, sd, mtd, floppy, 1210 pflash, virtio, none. 1211 1212 ``bus=bus,unit=unit`` 1213 These options define where is connected the drive by defining 1214 the bus number and the unit id. 1215 1216 ``index=index`` 1217 This option defines where is connected the drive by using an 1218 index in the list of available connectors of a given interface 1219 type. 1220 1221 ``media=media`` 1222 This option defines the type of the media: disk or cdrom. 1223 1224 ``snapshot=snapshot`` 1225 snapshot is "on" or "off" and controls snapshot mode for the 1226 given drive (see ``-snapshot``). 1227 1228 ``cache=cache`` 1229 cache is "none", "writeback", "unsafe", "directsync" or 1230 "writethrough" and controls how the host cache is used to access 1231 block data. This is a shortcut that sets the ``cache.direct`` 1232 and ``cache.no-flush`` options (as in ``-blockdev``), and 1233 additionally ``cache.writeback``, which provides a default for 1234 the ``write-cache`` option of block guest devices (as in 1235 ``-device``). The modes correspond to the following settings: 1236 1237 ============= =============== ============ ============== 1238 \ cache.writeback cache.direct cache.no-flush 1239 ============= =============== ============ ============== 1240 writeback on off off 1241 none on on off 1242 writethrough off off off 1243 directsync off on off 1244 unsafe on off on 1245 ============= =============== ============ ============== 1246 1247 The default mode is ``cache=writeback``. 1248 1249 ``aio=aio`` 1250 aio is "threads", or "native" and selects between pthread based 1251 disk I/O and native Linux AIO. 1252 1253 ``format=format`` 1254 Specify which disk format will be used rather than detecting the 1255 format. Can be used to specify format=raw to avoid interpreting 1256 an untrusted format header. 1257 1258 ``werror=action,rerror=action`` 1259 Specify which action to take on write and read errors. Valid 1260 actions are: "ignore" (ignore the error and try to continue), 1261 "stop" (pause QEMU), "report" (report the error to the guest), 1262 "enospc" (pause QEMU only if the host disk is full; report the 1263 error to the guest otherwise). The default setting is 1264 ``werror=enospc`` and ``rerror=report``. 1265 1266 ``copy-on-read=copy-on-read`` 1267 copy-on-read is "on" or "off" and enables whether to copy read 1268 backing file sectors into the image file. 1269 1270 ``bps=b,bps_rd=r,bps_wr=w`` 1271 Specify bandwidth throttling limits in bytes per second, either 1272 for all request types or for reads or writes only. Small values 1273 can lead to timeouts or hangs inside the guest. A safe minimum 1274 for disks is 2 MB/s. 1275 1276 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1277 Specify bursts in bytes per second, either for all request types 1278 or for reads or writes only. Bursts allow the guest I/O to spike 1279 above the limit temporarily. 1280 1281 ``iops=i,iops_rd=r,iops_wr=w`` 1282 Specify request rate limits in requests per second, either for 1283 all request types or for reads or writes only. 1284 1285 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1286 Specify bursts in requests per second, either for all request 1287 types or for reads or writes only. Bursts allow the guest I/O to 1288 spike above the limit temporarily. 1289 1290 ``iops_size=is`` 1291 Let every is bytes of a request count as a new request for iops 1292 throttling purposes. Use this option to prevent guests from 1293 circumventing iops limits by sending fewer but larger requests. 1294 1295 ``group=g`` 1296 Join a throttling quota group with given name g. All drives that 1297 are members of the same group are accounted for together. Use 1298 this option to prevent guests from circumventing throttling 1299 limits by using many small disks instead of a single larger 1300 disk. 1301 1302 By default, the ``cache.writeback=on`` mode is used. It will report 1303 data writes as completed as soon as the data is present in the host 1304 page cache. This is safe as long as your guest OS makes sure to 1305 correctly flush disk caches where needed. If your guest OS does not 1306 handle volatile disk write caches correctly and your host crashes or 1307 loses power, then the guest may experience data corruption. 1308 1309 For such guests, you should consider using ``cache.writeback=off``. 1310 This means that the host page cache will be used to read and write 1311 data, but write notification will be sent to the guest only after 1312 QEMU has made sure to flush each write to the disk. Be aware that 1313 this has a major impact on performance. 1314 1315 When using the ``-snapshot`` option, unsafe caching is always used. 1316 1317 Copy-on-read avoids accessing the same backing file sectors 1318 repeatedly and is useful when the backing file is over a slow 1319 network. By default copy-on-read is off. 1320 1321 Instead of ``-cdrom`` you can use: 1322 1323 .. parsed-literal:: 1324 1325 |qemu_system| -drive file=file,index=2,media=cdrom 1326 1327 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1328 1329 .. parsed-literal:: 1330 1331 |qemu_system| -drive file=file,index=0,media=disk 1332 |qemu_system| -drive file=file,index=1,media=disk 1333 |qemu_system| -drive file=file,index=2,media=disk 1334 |qemu_system| -drive file=file,index=3,media=disk 1335 1336 You can open an image using pre-opened file descriptors from an fd 1337 set: 1338 1339 .. parsed-literal:: 1340 1341 |qemu_system| \ 1342 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \ 1343 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \ 1344 -drive file=/dev/fdset/2,index=0,media=disk 1345 1346 You can connect a CDROM to the slave of ide0: 1347 1348 .. parsed-literal:: 1349 1350 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1351 1352 If you don't specify the "file=" argument, you define an empty 1353 drive: 1354 1355 .. parsed-literal:: 1356 1357 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1358 1359 Instead of ``-fda``, ``-fdb``, you can use: 1360 1361 .. parsed-literal:: 1362 1363 |qemu_system_x86| -drive file=file,index=0,if=floppy 1364 |qemu_system_x86| -drive file=file,index=1,if=floppy 1365 1366 By default, interface is "ide" and index is automatically 1367 incremented: 1368 1369 .. parsed-literal:: 1370 1371 |qemu_system_x86| -drive file=a -drive file=b" 1372 1373 is interpreted like: 1374 1375 .. parsed-literal:: 1376 1377 |qemu_system_x86| -hda a -hdb b 1378ERST 1379 1380DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1381 "-mtdblock file use 'file' as on-board Flash memory image\n", 1382 QEMU_ARCH_ALL) 1383SRST 1384``-mtdblock file`` 1385 Use file as on-board Flash memory image. 1386ERST 1387 1388DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1389 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1390SRST 1391``-sd file`` 1392 Use file as SecureDigital card image. 1393ERST 1394 1395DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1396 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1397SRST 1398``-pflash file`` 1399 Use file as a parallel flash image. 1400ERST 1401 1402DEF("snapshot", 0, QEMU_OPTION_snapshot, 1403 "-snapshot write to temporary files instead of disk image files\n", 1404 QEMU_ARCH_ALL) 1405SRST 1406``-snapshot`` 1407 Write to temporary files instead of disk image files. In this case, 1408 the raw disk image you use is not written back. You can however 1409 force the write back by pressing C-a s (see 1410 :ref:`disk_005fimages`). 1411ERST 1412 1413DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1414 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1415 " [,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode]\n" 1416 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1417 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1418 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1419 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1420 " [[,throttling.iops-size=is]]\n" 1421 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly]\n" 1422 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly]\n" 1423 "-fsdev synth,id=id\n", 1424 QEMU_ARCH_ALL) 1425 1426SRST 1427``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1428 \ 1429``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly]`` 1430 \ 1431``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly]`` 1432 \ 1433``-fsdev synth,id=id[,readonly]`` 1434 Define a new file system device. Valid options are: 1435 1436 ``local`` 1437 Accesses to the filesystem are done by QEMU. 1438 1439 ``proxy`` 1440 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1441 1442 ``synth`` 1443 Synthetic filesystem, only used by QTests. 1444 1445 ``id=id`` 1446 Specifies identifier for this device. 1447 1448 ``path=path`` 1449 Specifies the export path for the file system device. Files 1450 under this path will be available to the 9p client on the guest. 1451 1452 ``security_model=security_model`` 1453 Specifies the security model to be used for this export path. 1454 Supported security models are "passthrough", "mapped-xattr", 1455 "mapped-file" and "none". In "passthrough" security model, files 1456 are stored using the same credentials as they are created on the 1457 guest. This requires QEMU to run as root. In "mapped-xattr" 1458 security model, some of the file attributes like uid, gid, mode 1459 bits and link target are stored as file attributes. For 1460 "mapped-file" these attributes are stored in the hidden 1461 .virtfs\_metadata directory. Directories exported by this 1462 security model cannot interact with other unix tools. "none" 1463 security model is same as passthrough except the sever won't 1464 report failures if it fails to set file attributes like 1465 ownership. Security model is mandatory only for local fsdriver. 1466 Other fsdrivers (like proxy) don't take security model as a 1467 parameter. 1468 1469 ``writeout=writeout`` 1470 This is an optional argument. The only supported value is 1471 "immediate". This means that host page cache will be used to 1472 read and write data but write notification will be sent to the 1473 guest only when the data has been reported as written by the 1474 storage subsystem. 1475 1476 ``readonly`` 1477 Enables exporting 9p share as a readonly mount for guests. By 1478 default read-write access is given. 1479 1480 ``socket=socket`` 1481 Enables proxy filesystem driver to use passed socket file for 1482 communicating with virtfs-proxy-helper(1). 1483 1484 ``sock_fd=sock_fd`` 1485 Enables proxy filesystem driver to use passed socket descriptor 1486 for communicating with virtfs-proxy-helper(1). Usually a helper 1487 like libvirt will create socketpair and pass one of the fds as 1488 sock\_fd. 1489 1490 ``fmode=fmode`` 1491 Specifies the default mode for newly created files on the host. 1492 Works only with security models "mapped-xattr" and 1493 "mapped-file". 1494 1495 ``dmode=dmode`` 1496 Specifies the default mode for newly created directories on the 1497 host. Works only with security models "mapped-xattr" and 1498 "mapped-file". 1499 1500 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1501 Specify bandwidth throttling limits in bytes per second, either 1502 for all request types or for reads or writes only. 1503 1504 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1505 Specify bursts in bytes per second, either for all request types 1506 or for reads or writes only. Bursts allow the guest I/O to spike 1507 above the limit temporarily. 1508 1509 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1510 Specify request rate limits in requests per second, either for 1511 all request types or for reads or writes only. 1512 1513 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1514 Specify bursts in requests per second, either for all request 1515 types or for reads or writes only. Bursts allow the guest I/O to 1516 spike above the limit temporarily. 1517 1518 ``throttling.iops-size=is`` 1519 Let every is bytes of a request count as a new request for iops 1520 throttling purposes. 1521 1522 -fsdev option is used along with -device driver "virtio-9p-...". 1523 1524``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1525 Options for virtio-9p-... driver are: 1526 1527 ``type`` 1528 Specifies the variant to be used. Supported values are "pci", 1529 "ccw" or "device", depending on the machine type. 1530 1531 ``fsdev=id`` 1532 Specifies the id value specified along with -fsdev option. 1533 1534 ``mount_tag=mount_tag`` 1535 Specifies the tag name to be used by the guest to mount this 1536 export point. 1537ERST 1538 1539DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1540 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1541 " [,id=id][,writeout=immediate][,readonly][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1542 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly]\n" 1543 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly]\n" 1544 "-virtfs synth,mount_tag=tag[,id=id][,readonly]\n", 1545 QEMU_ARCH_ALL) 1546 1547SRST 1548``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1549 \ 1550``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly]`` 1551 \ 1552``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly]`` 1553 \ 1554``-virtfs synth,mount_tag=mount_tag`` 1555 Define a new virtual filesystem device and expose it to the guest using 1556 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1557 directory on host is made directly accessible by guest as a pass-through 1558 file system by using the 9P network protocol for communication between 1559 host and guests, if desired even accessible, shared by several guests 1560 simultaniously. 1561 1562 Note that ``-virtfs`` is actually just a convenience shortcut for its 1563 generalized form ``-fsdev -device virtio-9p-pci``. 1564 1565 The general form of pass-through file system options are: 1566 1567 ``local`` 1568 Accesses to the filesystem are done by QEMU. 1569 1570 ``proxy`` 1571 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1572 1573 ``synth`` 1574 Synthetic filesystem, only used by QTests. 1575 1576 ``id=id`` 1577 Specifies identifier for the filesystem device 1578 1579 ``path=path`` 1580 Specifies the export path for the file system device. Files 1581 under this path will be available to the 9p client on the guest. 1582 1583 ``security_model=security_model`` 1584 Specifies the security model to be used for this export path. 1585 Supported security models are "passthrough", "mapped-xattr", 1586 "mapped-file" and "none". In "passthrough" security model, files 1587 are stored using the same credentials as they are created on the 1588 guest. This requires QEMU to run as root. In "mapped-xattr" 1589 security model, some of the file attributes like uid, gid, mode 1590 bits and link target are stored as file attributes. For 1591 "mapped-file" these attributes are stored in the hidden 1592 .virtfs\_metadata directory. Directories exported by this 1593 security model cannot interact with other unix tools. "none" 1594 security model is same as passthrough except the sever won't 1595 report failures if it fails to set file attributes like 1596 ownership. Security model is mandatory only for local fsdriver. 1597 Other fsdrivers (like proxy) don't take security model as a 1598 parameter. 1599 1600 ``writeout=writeout`` 1601 This is an optional argument. The only supported value is 1602 "immediate". This means that host page cache will be used to 1603 read and write data but write notification will be sent to the 1604 guest only when the data has been reported as written by the 1605 storage subsystem. 1606 1607 ``readonly`` 1608 Enables exporting 9p share as a readonly mount for guests. By 1609 default read-write access is given. 1610 1611 ``socket=socket`` 1612 Enables proxy filesystem driver to use passed socket file for 1613 communicating with virtfs-proxy-helper(1). Usually a helper like 1614 libvirt will create socketpair and pass one of the fds as 1615 sock\_fd. 1616 1617 ``sock_fd`` 1618 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1619 socket descriptor for interfacing with virtfs-proxy-helper(1). 1620 1621 ``fmode=fmode`` 1622 Specifies the default mode for newly created files on the host. 1623 Works only with security models "mapped-xattr" and 1624 "mapped-file". 1625 1626 ``dmode=dmode`` 1627 Specifies the default mode for newly created directories on the 1628 host. Works only with security models "mapped-xattr" and 1629 "mapped-file". 1630 1631 ``mount_tag=mount_tag`` 1632 Specifies the tag name to be used by the guest to mount this 1633 export point. 1634 1635 ``multidevs=multidevs`` 1636 Specifies how to deal with multiple devices being shared with a 1637 9p export. Supported behaviours are either "remap", "forbid" or 1638 "warn". The latter is the default behaviour on which virtfs 9p 1639 expects only one device to be shared with the same export, and 1640 if more than one device is shared and accessed via the same 9p 1641 export then only a warning message is logged (once) by qemu on 1642 host side. In order to avoid file ID collisions on guest you 1643 should either create a separate virtfs export for each device to 1644 be shared with guests (recommended way) or you might use "remap" 1645 instead which allows you to share multiple devices with only one 1646 export instead, which is achieved by remapping the original 1647 inode numbers from host to guest in a way that would prevent 1648 such collisions. Remapping inodes in such use cases is required 1649 because the original device IDs from host are never passed and 1650 exposed on guest. Instead all files of an export shared with 1651 virtfs always share the same device id on guest. So two files 1652 with identical inode numbers but from actually different devices 1653 on host would otherwise cause a file ID collision and hence 1654 potential misbehaviours on guest. "forbid" on the other hand 1655 assumes like "warn" that only one device is shared by the same 1656 export, however it will not only log a warning message but also 1657 deny access to additional devices on guest. Note though that 1658 "forbid" does currently not block all possible file access 1659 operations (e.g. readdir() would still return entries from other 1660 devices). 1661ERST 1662 1663DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1664 "-iscsi [user=user][,password=password]\n" 1665 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1666 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1667 " [,timeout=timeout]\n" 1668 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1669 1670SRST 1671``-iscsi`` 1672 Configure iSCSI session parameters. 1673ERST 1674 1675DEFHEADING() 1676 1677DEFHEADING(USB options:) 1678 1679DEF("usb", 0, QEMU_OPTION_usb, 1680 "-usb enable on-board USB host controller (if not enabled by default)\n", 1681 QEMU_ARCH_ALL) 1682SRST 1683``-usb`` 1684 Enable USB emulation on machine types with an on-board USB host 1685 controller (if not enabled by default). Note that on-board USB host 1686 controllers may not support USB 3.0. In this case 1687 ``-device qemu-xhci`` can be used instead on machines with PCI. 1688ERST 1689 1690DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1691 "-usbdevice name add the host or guest USB device 'name'\n", 1692 QEMU_ARCH_ALL) 1693SRST 1694``-usbdevice devname`` 1695 Add the USB device devname. Note that this option is deprecated, 1696 please use ``-device usb-...`` instead. See 1697 :ref:`usb_005fdevices`. 1698 1699 ``mouse`` 1700 Virtual Mouse. This will override the PS/2 mouse emulation when 1701 activated. 1702 1703 ``tablet`` 1704 Pointer device that uses absolute coordinates (like a 1705 touchscreen). This means QEMU is able to report the mouse 1706 position without having to grab the mouse. Also overrides the 1707 PS/2 mouse emulation when activated. 1708 1709 ``braille`` 1710 Braille device. This will use BrlAPI to display the braille 1711 output on a real or fake device. 1712ERST 1713 1714DEFHEADING() 1715 1716DEFHEADING(Display options:) 1717 1718DEF("display", HAS_ARG, QEMU_OPTION_display, 1719#if defined(CONFIG_SPICE) 1720 "-display spice-app[,gl=on|off]\n" 1721#endif 1722#if defined(CONFIG_SDL) 1723 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1724 " [,window_close=on|off][,gl=on|core|es|off]\n" 1725#endif 1726#if defined(CONFIG_GTK) 1727 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1728#endif 1729#if defined(CONFIG_VNC) 1730 "-display vnc=<display>[,<optargs>]\n" 1731#endif 1732#if defined(CONFIG_CURSES) 1733 "-display curses[,charset=<encoding>]\n" 1734#endif 1735#if defined(CONFIG_OPENGL) 1736 "-display egl-headless[,rendernode=<file>]\n" 1737#endif 1738 "-display none\n" 1739 " select display backend type\n" 1740 " The default display is equivalent to\n " 1741#if defined(CONFIG_GTK) 1742 "\"-display gtk\"\n" 1743#elif defined(CONFIG_SDL) 1744 "\"-display sdl\"\n" 1745#elif defined(CONFIG_COCOA) 1746 "\"-display cocoa\"\n" 1747#elif defined(CONFIG_VNC) 1748 "\"-vnc localhost:0,to=99,id=default\"\n" 1749#else 1750 "\"-display none\"\n" 1751#endif 1752 , QEMU_ARCH_ALL) 1753SRST 1754``-display type`` 1755 Select type of display to use. This option is a replacement for the 1756 old style -sdl/-curses/... options. Use ``-display help`` to list 1757 the available display types. Valid values for type are 1758 1759 ``sdl`` 1760 Display video output via SDL (usually in a separate graphics 1761 window; see the SDL documentation for other possibilities). 1762 1763 ``curses`` 1764 Display video output via curses. For graphics device models 1765 which support a text mode, QEMU can display this output using a 1766 curses/ncurses interface. Nothing is displayed when the graphics 1767 device is in graphical mode or if the graphics device does not 1768 support a text mode. Generally only the VGA device models 1769 support text mode. The font charset used by the guest can be 1770 specified with the ``charset`` option, for example 1771 ``charset=CP850`` for IBM CP850 encoding. The default is 1772 ``CP437``. 1773 1774 ``none`` 1775 Do not display video output. The guest will still see an 1776 emulated graphics card, but its output will not be displayed to 1777 the QEMU user. This option differs from the -nographic option in 1778 that it only affects what is done with video output; -nographic 1779 also changes the destination of the serial and parallel port 1780 data. 1781 1782 ``gtk`` 1783 Display video output in a GTK window. This interface provides 1784 drop-down menus and other UI elements to configure and control 1785 the VM during runtime. 1786 1787 ``vnc`` 1788 Start a VNC server on display <arg> 1789 1790 ``egl-headless`` 1791 Offload all OpenGL operations to a local DRI device. For any 1792 graphical display, this display needs to be paired with either 1793 VNC or SPICE displays. 1794 1795 ``spice-app`` 1796 Start QEMU as a Spice server and launch the default Spice client 1797 application. The Spice server will redirect the serial consoles 1798 and QEMU monitors. (Since 4.0) 1799ERST 1800 1801DEF("nographic", 0, QEMU_OPTION_nographic, 1802 "-nographic disable graphical output and redirect serial I/Os to console\n", 1803 QEMU_ARCH_ALL) 1804SRST 1805``-nographic`` 1806 Normally, if QEMU is compiled with graphical window support, it 1807 displays output such as guest graphics, guest console, and the QEMU 1808 monitor in a window. With this option, you can totally disable 1809 graphical output so that QEMU is a simple command line application. 1810 The emulated serial port is redirected on the console and muxed with 1811 the monitor (unless redirected elsewhere explicitly). Therefore, you 1812 can still use QEMU to debug a Linux kernel with a serial console. 1813 Use C-a h for help on switching between the console and monitor. 1814ERST 1815 1816DEF("curses", 0, QEMU_OPTION_curses, 1817 "-curses shorthand for -display curses\n", 1818 QEMU_ARCH_ALL) 1819SRST 1820``-curses`` 1821 Normally, if QEMU is compiled with graphical window support, it 1822 displays output such as guest graphics, guest console, and the QEMU 1823 monitor in a window. With this option, QEMU can display the VGA 1824 output when in text mode using a curses/ncurses interface. Nothing 1825 is displayed in graphical mode. 1826ERST 1827 1828DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1829 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1830 QEMU_ARCH_ALL) 1831SRST 1832``-alt-grab`` 1833 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1834 this also affects the special keys (for fullscreen, monitor-mode 1835 switching, etc). 1836ERST 1837 1838DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1839 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1840 QEMU_ARCH_ALL) 1841SRST 1842``-ctrl-grab`` 1843 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1844 also affects the special keys (for fullscreen, monitor-mode 1845 switching, etc). 1846ERST 1847 1848DEF("no-quit", 0, QEMU_OPTION_no_quit, 1849 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1850SRST 1851``-no-quit`` 1852 Disable SDL window close capability. 1853ERST 1854 1855DEF("sdl", 0, QEMU_OPTION_sdl, 1856 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1857SRST 1858``-sdl`` 1859 Enable SDL. 1860ERST 1861 1862DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1863 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1864 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1865 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1866 " [,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]\n" 1867 " [,tls-ciphers=<list>]\n" 1868 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1869 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1870 " [,sasl][,password=<secret>][,disable-ticketing]\n" 1871 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1872 " [,jpeg-wan-compression=[auto|never|always]]\n" 1873 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1874 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n" 1875 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n" 1876 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1877 " [,gl=[on|off]][,rendernode=<file>]\n" 1878 " enable spice\n" 1879 " at least one of {port, tls-port} is mandatory\n", 1880 QEMU_ARCH_ALL) 1881SRST 1882``-spice option[,option[,...]]`` 1883 Enable the spice remote desktop protocol. Valid options are 1884 1885 ``port=<nr>`` 1886 Set the TCP port spice is listening on for plaintext channels. 1887 1888 ``addr=<addr>`` 1889 Set the IP address spice is listening on. Default is any 1890 address. 1891 1892 ``ipv4``; \ ``ipv6``; \ ``unix`` 1893 Force using the specified IP version. 1894 1895 ``password=<secret>`` 1896 Set the password you need to authenticate. 1897 1898 ``sasl`` 1899 Require that the client use SASL to authenticate with the spice. 1900 The exact choice of authentication method used is controlled 1901 from the system / user's SASL configuration file for the 'qemu' 1902 service. This is typically found in /etc/sasl2/qemu.conf. If 1903 running QEMU as an unprivileged user, an environment variable 1904 SASL\_CONF\_PATH can be used to make it search alternate 1905 locations for the service config. While some SASL auth methods 1906 can also provide data encryption (eg GSSAPI), it is recommended 1907 that SASL always be combined with the 'tls' and 'x509' settings 1908 to enable use of SSL and server certificates. This ensures a 1909 data encryption preventing compromise of authentication 1910 credentials. 1911 1912 ``disable-ticketing`` 1913 Allow client connects without authentication. 1914 1915 ``disable-copy-paste`` 1916 Disable copy paste between the client and the guest. 1917 1918 ``disable-agent-file-xfer`` 1919 Disable spice-vdagent based file-xfer between the client and the 1920 guest. 1921 1922 ``tls-port=<nr>`` 1923 Set the TCP port spice is listening on for encrypted channels. 1924 1925 ``x509-dir=<dir>`` 1926 Set the x509 file directory. Expects same filenames as -vnc 1927 $display,x509=$dir 1928 1929 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 1930 The x509 file names can also be configured individually. 1931 1932 ``tls-ciphers=<list>`` 1933 Specify which ciphers to use. 1934 1935 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 1936 Force specific channel to be used with or without TLS 1937 encryption. The options can be specified multiple times to 1938 configure multiple channels. The special name "default" can be 1939 used to set the default mode. For channels which are not 1940 explicitly forced into one mode the spice client is allowed to 1941 pick tls/plaintext as he pleases. 1942 1943 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 1944 Configure image compression (lossless). Default is auto\_glz. 1945 1946 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 1947 Configure wan image compression (lossy for slow links). Default 1948 is auto. 1949 1950 ``streaming-video=[off|all|filter]`` 1951 Configure video stream detection. Default is off. 1952 1953 ``agent-mouse=[on|off]`` 1954 Enable/disable passing mouse events via vdagent. Default is on. 1955 1956 ``playback-compression=[on|off]`` 1957 Enable/disable audio stream compression (using celt 0.5.1). 1958 Default is on. 1959 1960 ``seamless-migration=[on|off]`` 1961 Enable/disable spice seamless migration. Default is off. 1962 1963 ``gl=[on|off]`` 1964 Enable/disable OpenGL context. Default is off. 1965 1966 ``rendernode=<file>`` 1967 DRM render node for OpenGL rendering. If not specified, it will 1968 pick the first available. (Since 2.9) 1969ERST 1970 1971DEF("portrait", 0, QEMU_OPTION_portrait, 1972 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 1973 QEMU_ARCH_ALL) 1974SRST 1975``-portrait`` 1976 Rotate graphical output 90 deg left (only PXA LCD). 1977ERST 1978 1979DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 1980 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 1981 QEMU_ARCH_ALL) 1982SRST 1983``-rotate deg`` 1984 Rotate graphical output some deg left (only PXA LCD). 1985ERST 1986 1987DEF("vga", HAS_ARG, QEMU_OPTION_vga, 1988 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 1989 " select video card type\n", QEMU_ARCH_ALL) 1990SRST 1991``-vga type`` 1992 Select type of VGA card to emulate. Valid values for type are 1993 1994 ``cirrus`` 1995 Cirrus Logic GD5446 Video card. All Windows versions starting 1996 from Windows 95 should recognize and use this graphic card. For 1997 optimal performances, use 16 bit color depth in the guest and 1998 the host OS. (This card was the default before QEMU 2.2) 1999 2000 ``std`` 2001 Standard VGA card with Bochs VBE extensions. If your guest OS 2002 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2003 you want to use high resolution modes (>= 1280x1024x16) then you 2004 should use this option. (This card is the default since QEMU 2005 2.2) 2006 2007 ``vmware`` 2008 VMWare SVGA-II compatible adapter. Use it if you have 2009 sufficiently recent XFree86/XOrg server or Windows guest with a 2010 driver for this card. 2011 2012 ``qxl`` 2013 QXL paravirtual graphic card. It is VGA compatible (including 2014 VESA 2.0 VBE support). Works best with qxl guest drivers 2015 installed though. Recommended choice when using the spice 2016 protocol. 2017 2018 ``tcx`` 2019 (sun4m only) Sun TCX framebuffer. This is the default 2020 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2021 colour depths at a fixed resolution of 1024x768. 2022 2023 ``cg3`` 2024 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2025 framebuffer for sun4m machines available in both 1024x768 2026 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2027 wishing to run older Solaris versions. 2028 2029 ``virtio`` 2030 Virtio VGA card. 2031 2032 ``none`` 2033 Disable VGA card. 2034ERST 2035 2036DEF("full-screen", 0, QEMU_OPTION_full_screen, 2037 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2038SRST 2039``-full-screen`` 2040 Start in full screen. 2041ERST 2042 2043DEF("g", HAS_ARG, QEMU_OPTION_g , 2044 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2045 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2046SRST 2047``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2048 Set the initial graphical resolution and depth (PPC, SPARC only). 2049 2050 For PPC the default is 800x600x32. 2051 2052 For SPARC with the TCX graphics device, the default is 1024x768x8 2053 with the option of 1024x768x24. For cgthree, the default is 2054 1024x768x8 with the option of 1152x900x8 for people who wish to use 2055 OBP. 2056ERST 2057 2058DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2059 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2060SRST 2061``-vnc display[,option[,option[,...]]]`` 2062 Normally, if QEMU is compiled with graphical window support, it 2063 displays output such as guest graphics, guest console, and the QEMU 2064 monitor in a window. With this option, you can have QEMU listen on 2065 VNC display display and redirect the VGA display over the VNC 2066 session. It is very useful to enable the usb tablet device when 2067 using this option (option ``-device usb-tablet``). When using the 2068 VNC display, you must use the ``-k`` parameter to set the keyboard 2069 layout if you are not using en-us. Valid syntax for the display is 2070 2071 ``to=L`` 2072 With this option, QEMU will try next available VNC displays, 2073 until the number L, if the origianlly defined "-vnc display" is 2074 not available, e.g. port 5900+display is already used by another 2075 application. By default, to=0. 2076 2077 ``host:d`` 2078 TCP connections will only be allowed from host on display d. By 2079 convention the TCP port is 5900+d. Optionally, host can be 2080 omitted in which case the server will accept connections from 2081 any host. 2082 2083 ``unix:path`` 2084 Connections will be allowed over UNIX domain sockets where path 2085 is the location of a unix socket to listen for connections on. 2086 2087 ``none`` 2088 VNC is initialized but not started. The monitor ``change`` 2089 command can be used to later start the VNC server. 2090 2091 Following the display value there may be one or more option flags 2092 separated by commas. Valid options are 2093 2094 ``reverse`` 2095 Connect to a listening VNC client via a "reverse" connection. 2096 The client is specified by the display. For reverse network 2097 connections (host:d,``reverse``), the d argument is a TCP port 2098 number, not a display number. 2099 2100 ``websocket`` 2101 Opens an additional TCP listening port dedicated to VNC 2102 Websocket connections. If a bare websocket option is given, the 2103 Websocket port is 5700+display. An alternative port can be 2104 specified with the syntax ``websocket``\ =port. 2105 2106 If host is specified connections will only be allowed from this 2107 host. It is possible to control the websocket listen address 2108 independently, using the syntax ``websocket``\ =host:port. 2109 2110 If no TLS credentials are provided, the websocket connection 2111 runs in unencrypted mode. If TLS credentials are provided, the 2112 websocket connection requires encrypted client connections. 2113 2114 ``password`` 2115 Require that password based authentication is used for client 2116 connections. 2117 2118 The password must be set separately using the ``set_password`` 2119 command in the :ref:`pcsys_005fmonitor`. The 2120 syntax to change your password is: 2121 ``set_password <protocol> <password>`` where <protocol> could be 2122 either "vnc" or "spice". 2123 2124 If you would like to change <protocol> password expiration, you 2125 should use ``expire_password <protocol> <expiration-time>`` 2126 where expiration time could be one of the following options: 2127 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2128 make password expire in 60 seconds, or 1335196800 to make 2129 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2130 this date and time). 2131 2132 You can also use keywords "now" or "never" for the expiration 2133 time to allow <protocol> password to expire immediately or never 2134 expire. 2135 2136 ``tls-creds=ID`` 2137 Provides the ID of a set of TLS credentials to use to secure the 2138 VNC server. They will apply to both the normal VNC server socket 2139 and the websocket socket (if enabled). Setting TLS credentials 2140 will cause the VNC server socket to enable the VeNCrypt auth 2141 mechanism. The credentials should have been previously created 2142 using the ``-object tls-creds`` argument. 2143 2144 ``tls-authz=ID`` 2145 Provides the ID of the QAuthZ authorization object against which 2146 the client's x509 distinguished name will validated. This object 2147 is only resolved at time of use, so can be deleted and recreated 2148 on the fly while the VNC server is active. If missing, it will 2149 default to denying access. 2150 2151 ``sasl`` 2152 Require that the client use SASL to authenticate with the VNC 2153 server. The exact choice of authentication method used is 2154 controlled from the system / user's SASL configuration file for 2155 the 'qemu' service. This is typically found in 2156 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2157 an environment variable SASL\_CONF\_PATH can be used to make it 2158 search alternate locations for the service config. While some 2159 SASL auth methods can also provide data encryption (eg GSSAPI), 2160 it is recommended that SASL always be combined with the 'tls' 2161 and 'x509' settings to enable use of SSL and server 2162 certificates. This ensures a data encryption preventing 2163 compromise of authentication credentials. See the 2164 :ref:`vnc_005fsecurity` section for details on 2165 using SASL authentication. 2166 2167 ``sasl-authz=ID`` 2168 Provides the ID of the QAuthZ authorization object against which 2169 the client's SASL username will validated. This object is only 2170 resolved at time of use, so can be deleted and recreated on the 2171 fly while the VNC server is active. If missing, it will default 2172 to denying access. 2173 2174 ``acl`` 2175 Legacy method for enabling authorization of clients against the 2176 x509 distinguished name and SASL username. It results in the 2177 creation of two ``authz-list`` objects with IDs of 2178 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2179 objects must be configured with the HMP ACL commands. 2180 2181 This option is deprecated and should no longer be used. The new 2182 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2183 2184 ``lossy`` 2185 Enable lossy compression methods (gradient, JPEG, ...). If this 2186 option is set, VNC client may receive lossy framebuffer updates 2187 depending on its encoding settings. Enabling this option can 2188 save a lot of bandwidth at the expense of quality. 2189 2190 ``non-adaptive`` 2191 Disable adaptive encodings. Adaptive encodings are enabled by 2192 default. An adaptive encoding will try to detect frequently 2193 updated screen regions, and send updates in these regions using 2194 a lossy encoding (like JPEG). This can be really helpful to save 2195 bandwidth when playing videos. Disabling adaptive encodings 2196 restores the original static behavior of encodings like Tight. 2197 2198 ``share=[allow-exclusive|force-shared|ignore]`` 2199 Set display sharing policy. 'allow-exclusive' allows clients to 2200 ask for exclusive access. As suggested by the rfb spec this is 2201 implemented by dropping other connections. Connecting multiple 2202 clients in parallel requires all clients asking for a shared 2203 session (vncviewer: -shared switch). This is the default. 2204 'force-shared' disables exclusive client access. Useful for 2205 shared desktop sessions, where you don't want someone forgetting 2206 specify -shared disconnect everybody else. 'ignore' completely 2207 ignores the shared flag and allows everybody connect 2208 unconditionally. Doesn't conform to the rfb spec but is 2209 traditional QEMU behavior. 2210 2211 ``key-delay-ms`` 2212 Set keyboard delay, for key down and key up events, in 2213 milliseconds. Default is 10. Keyboards are low-bandwidth 2214 devices, so this slowdown can help the device and guest to keep 2215 up and not lose events in case events are arriving in bulk. 2216 Possible causes for the latter are flaky network connections, or 2217 scripts for automated testing. 2218 2219 ``audiodev=audiodev`` 2220 Use the specified audiodev when the VNC client requests audio 2221 transmission. When not using an -audiodev argument, this option 2222 must be omitted, otherwise is must be present and specify a 2223 valid audiodev. 2224ERST 2225 2226ARCHHEADING(, QEMU_ARCH_I386) 2227 2228ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2229 2230DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2231 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2232 QEMU_ARCH_I386) 2233SRST 2234``-win2k-hack`` 2235 Use it when installing Windows 2000 to avoid a disk full bug. After 2236 Windows 2000 is installed, you no longer need this option (this 2237 option slows down the IDE transfers). 2238ERST 2239 2240DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2241 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2242 QEMU_ARCH_I386) 2243SRST 2244``-no-fd-bootchk`` 2245 Disable boot signature checking for floppy disks in BIOS. May be 2246 needed to boot from old floppy disks. 2247ERST 2248 2249DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2250 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2251SRST 2252``-no-acpi`` 2253 Disable ACPI (Advanced Configuration and Power Interface) support. 2254 Use it if your guest OS complains about ACPI problems (PC target 2255 machine only). 2256ERST 2257 2258DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2259 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2260SRST 2261``-no-hpet`` 2262 Disable HPET support. 2263ERST 2264 2265DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2266 "-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" 2267 " ACPI table description\n", QEMU_ARCH_I386) 2268SRST 2269``-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n] [,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]`` 2270 Add ACPI table with specified header fields and context from 2271 specified files. For file=, take whole ACPI table from the specified 2272 files, including all ACPI headers (possible overridden by other 2273 options). For data=, only data portion of the table is used, all 2274 header information is specified in the command line. If a SLIC table 2275 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2276 fields will override the same in the RSDT and the FADT (a.k.a. 2277 FACP), in order to ensure the field matches required by the 2278 Microsoft SLIC spec and the ACPI spec. 2279ERST 2280 2281DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2282 "-smbios file=binary\n" 2283 " load SMBIOS entry from binary file\n" 2284 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2285 " [,uefi=on|off]\n" 2286 " specify SMBIOS type 0 fields\n" 2287 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2288 " [,uuid=uuid][,sku=str][,family=str]\n" 2289 " specify SMBIOS type 1 fields\n" 2290 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2291 " [,asset=str][,location=str]\n" 2292 " specify SMBIOS type 2 fields\n" 2293 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2294 " [,sku=str]\n" 2295 " specify SMBIOS type 3 fields\n" 2296 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2297 " [,asset=str][,part=str]\n" 2298 " specify SMBIOS type 4 fields\n" 2299 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2300 " [,asset=str][,part=str][,speed=%d]\n" 2301 " specify SMBIOS type 17 fields\n", 2302 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2303SRST 2304``-smbios file=binary`` 2305 Load SMBIOS entry from binary file. 2306 2307``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2308 Specify SMBIOS type 0 fields 2309 2310``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2311 Specify SMBIOS type 1 fields 2312 2313``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2314 Specify SMBIOS type 2 fields 2315 2316``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2317 Specify SMBIOS type 3 fields 2318 2319``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2320 Specify SMBIOS type 4 fields 2321 2322``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2323 Specify SMBIOS type 17 fields 2324ERST 2325 2326DEFHEADING() 2327 2328DEFHEADING(Network options:) 2329 2330DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2331#ifdef CONFIG_SLIRP 2332 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n" 2333 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2334 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2335 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2336 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2337#ifndef _WIN32 2338 "[,smb=dir[,smbserver=addr]]\n" 2339#endif 2340 " configure a user mode network backend with ID 'str',\n" 2341 " its DHCP server and optional services\n" 2342#endif 2343#ifdef _WIN32 2344 "-netdev tap,id=str,ifname=name\n" 2345 " configure a host TAP network backend with ID 'str'\n" 2346#else 2347 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2348 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2349 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2350 " [,poll-us=n]\n" 2351 " configure a host TAP network backend with ID 'str'\n" 2352 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2353 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2354 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2355 " to deconfigure it\n" 2356 " use '[down]script=no' to disable script execution\n" 2357 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2358 " configure it\n" 2359 " use 'fd=h' to connect to an already opened TAP interface\n" 2360 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2361 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2362 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2363 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2364 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2365 " use vhost=on to enable experimental in kernel accelerator\n" 2366 " (only has effect for virtio guests which use MSIX)\n" 2367 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2368 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2369 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2370 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2371 " use 'poll-us=n' to speciy the maximum number of microseconds that could be\n" 2372 " spent on busy polling for vhost net\n" 2373 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2374 " configure a host TAP network backend with ID 'str' that is\n" 2375 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2376 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2377#endif 2378#ifdef __linux__ 2379 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2380 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n" 2381 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n" 2382 " [,rxcookie=rxcookie][,offset=offset]\n" 2383 " configure a network backend with ID 'str' connected to\n" 2384 " an Ethernet over L2TPv3 pseudowire.\n" 2385 " Linux kernel 3.3+ as well as most routers can talk\n" 2386 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2387 " VM to a router and even VM to Host. It is a nearly-universal\n" 2388 " standard (RFC3931). Note - this implementation uses static\n" 2389 " pre-configured tunnels (same as the Linux kernel).\n" 2390 " use 'src=' to specify source address\n" 2391 " use 'dst=' to specify destination address\n" 2392 " use 'udp=on' to specify udp encapsulation\n" 2393 " use 'srcport=' to specify source udp port\n" 2394 " use 'dstport=' to specify destination udp port\n" 2395 " use 'ipv6=on' to force v6\n" 2396 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2397 " well as a weak security measure\n" 2398 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2399 " use 'txcookie=0x012345678' to specify a txcookie\n" 2400 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2401 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2402 " use 'pincounter=on' to work around broken counter handling in peer\n" 2403 " use 'offset=X' to add an extra offset between header and data\n" 2404#endif 2405 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2406 " configure a network backend to connect to another network\n" 2407 " using a socket connection\n" 2408 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2409 " configure a network backend to connect to a multicast maddr and port\n" 2410 " use 'localaddr=addr' to specify the host address to send packets from\n" 2411 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2412 " configure a network backend to connect to another network\n" 2413 " using an UDP tunnel\n" 2414#ifdef CONFIG_VDE 2415 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2416 " configure a network backend to connect to port 'n' of a vde switch\n" 2417 " running on host and listening for incoming connections on 'socketpath'.\n" 2418 " Use group 'groupname' and mode 'octalmode' to change default\n" 2419 " ownership and permissions for communication port.\n" 2420#endif 2421#ifdef CONFIG_NETMAP 2422 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2423 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2424 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2425 " netmap device, defaults to '/dev/netmap')\n" 2426#endif 2427#ifdef CONFIG_POSIX 2428 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2429 " configure a vhost-user network, backed by a chardev 'dev'\n" 2430#endif 2431#ifdef __linux__ 2432 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2433 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2434#endif 2435 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2436 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2437DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2438 "-nic [tap|bridge|" 2439#ifdef CONFIG_SLIRP 2440 "user|" 2441#endif 2442#ifdef __linux__ 2443 "l2tpv3|" 2444#endif 2445#ifdef CONFIG_VDE 2446 "vde|" 2447#endif 2448#ifdef CONFIG_NETMAP 2449 "netmap|" 2450#endif 2451#ifdef CONFIG_POSIX 2452 "vhost-user|" 2453#endif 2454 "socket][,option][,...][mac=macaddr]\n" 2455 " initialize an on-board / default host NIC (using MAC address\n" 2456 " macaddr) and connect it to the given host network backend\n" 2457 "-nic none use it alone to have zero network devices (the default is to\n" 2458 " provided a 'user' network connection)\n", 2459 QEMU_ARCH_ALL) 2460DEF("net", HAS_ARG, QEMU_OPTION_net, 2461 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2462 " configure or create an on-board (or machine default) NIC and\n" 2463 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2464 "-net [" 2465#ifdef CONFIG_SLIRP 2466 "user|" 2467#endif 2468 "tap|" 2469 "bridge|" 2470#ifdef CONFIG_VDE 2471 "vde|" 2472#endif 2473#ifdef CONFIG_NETMAP 2474 "netmap|" 2475#endif 2476 "socket][,option][,option][,...]\n" 2477 " old way to initialize a host network interface\n" 2478 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2479SRST 2480``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2481 This option is a shortcut for configuring both the on-board 2482 (default) guest NIC hardware and the host network backend in one go. 2483 The host backend options are the same as with the corresponding 2484 ``-netdev`` options below. The guest NIC model can be set with 2485 ``model=modelname``. Use ``model=help`` to list the available device 2486 types. The hardware MAC address can be set with ``mac=macaddr``. 2487 2488 The following two example do exactly the same, to show how ``-nic`` 2489 can be used to shorten the command line length: 2490 2491 .. parsed-literal:: 2492 2493 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2494 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2495 2496``-nic none`` 2497 Indicate that no network devices should be configured. It is used to 2498 override the default configuration (default NIC with "user" host 2499 network backend) which is activated if no other networking options 2500 are provided. 2501 2502``-netdev user,id=id[,option][,option][,...]`` 2503 Configure user mode host network backend which requires no 2504 administrator privilege to run. Valid options are: 2505 2506 ``id=id`` 2507 Assign symbolic name for use in monitor commands. 2508 2509 ``ipv4=on|off and ipv6=on|off`` 2510 Specify that either IPv4 or IPv6 must be enabled. If neither is 2511 specified both protocols are enabled. 2512 2513 ``net=addr[/mask]`` 2514 Set IP network address the guest will see. Optionally specify 2515 the netmask, either in the form a.b.c.d or as number of valid 2516 top-most bits. Default is 10.0.2.0/24. 2517 2518 ``host=addr`` 2519 Specify the guest-visible address of the host. Default is the 2520 2nd IP in the guest network, i.e. x.x.x.2. 2521 2522 ``ipv6-net=addr[/int]`` 2523 Set IPv6 network address the guest will see (default is 2524 fec0::/64). The network prefix is given in the usual hexadecimal 2525 IPv6 address notation. The prefix size is optional, and is given 2526 as the number of valid top-most bits (default is 64). 2527 2528 ``ipv6-host=addr`` 2529 Specify the guest-visible IPv6 address of the host. Default is 2530 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2531 2532 ``restrict=on|off`` 2533 If this option is enabled, the guest will be isolated, i.e. it 2534 will not be able to contact the host and no guest IP packets 2535 will be routed over the host to the outside. This option does 2536 not affect any explicitly set forwarding rules. 2537 2538 ``hostname=name`` 2539 Specifies the client hostname reported by the built-in DHCP 2540 server. 2541 2542 ``dhcpstart=addr`` 2543 Specify the first of the 16 IPs the built-in DHCP server can 2544 assign. Default is the 15th to 31st IP in the guest network, 2545 i.e. x.x.x.15 to x.x.x.31. 2546 2547 ``dns=addr`` 2548 Specify the guest-visible address of the virtual nameserver. The 2549 address must be different from the host address. Default is the 2550 3rd IP in the guest network, i.e. x.x.x.3. 2551 2552 ``ipv6-dns=addr`` 2553 Specify the guest-visible address of the IPv6 virtual 2554 nameserver. The address must be different from the host address. 2555 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2556 2557 ``dnssearch=domain`` 2558 Provides an entry for the domain-search list sent by the 2559 built-in DHCP server. More than one domain suffix can be 2560 transmitted by specifying this option multiple times. If 2561 supported, this will cause the guest to automatically try to 2562 append the given domain suffix(es) in case a domain name can not 2563 be resolved. 2564 2565 Example: 2566 2567 .. parsed-literal:: 2568 2569 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2570 2571 ``domainname=domain`` 2572 Specifies the client domain name reported by the built-in DHCP 2573 server. 2574 2575 ``tftp=dir`` 2576 When using the user mode network stack, activate a built-in TFTP 2577 server. The files in dir will be exposed as the root of a TFTP 2578 server. The TFTP client on the guest must be configured in 2579 binary mode (use the command ``bin`` of the Unix TFTP client). 2580 2581 ``tftp-server-name=name`` 2582 In BOOTP reply, broadcast name as the "TFTP server name" 2583 (RFC2132 option 66). This can be used to advise the guest to 2584 load boot files or configurations from a different server than 2585 the host address. 2586 2587 ``bootfile=file`` 2588 When using the user mode network stack, broadcast file as the 2589 BOOTP filename. In conjunction with ``tftp``, this can be used 2590 to network boot a guest from a local directory. 2591 2592 Example (using pxelinux): 2593 2594 .. parsed-literal:: 2595 2596 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \ 2597 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2598 2599 ``smb=dir[,smbserver=addr]`` 2600 When using the user mode network stack, activate a built-in SMB 2601 server so that Windows OSes can access to the host files in 2602 ``dir`` transparently. The IP address of the SMB server can be 2603 set to addr. By default the 4th IP in the guest network is used, 2604 i.e. x.x.x.4. 2605 2606 In the guest Windows OS, the line: 2607 2608 :: 2609 2610 10.0.2.4 smbserver 2611 2612 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2613 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2614 NT/2000). 2615 2616 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2617 2618 Note that a SAMBA server must be installed on the host OS. 2619 2620 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2621 Redirect incoming TCP or UDP connections to the host port 2622 hostport to the guest IP address guestaddr on guest port 2623 guestport. If guestaddr is not specified, its value is x.x.x.15 2624 (default first address given by the built-in DHCP server). By 2625 specifying hostaddr, the rule can be bound to a specific host 2626 interface. If no connection type is set, TCP is used. This 2627 option can be given multiple times. 2628 2629 For example, to redirect host X11 connection from screen 1 to 2630 guest screen 0, use the following: 2631 2632 .. parsed-literal:: 2633 2634 # on the host 2635 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2636 # this host xterm should open in the guest X11 server 2637 xterm -display :1 2638 2639 To redirect telnet connections from host port 5555 to telnet 2640 port on the guest, use the following: 2641 2642 .. parsed-literal:: 2643 2644 # on the host 2645 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2646 telnet localhost 5555 2647 2648 Then when you use on the host ``telnet localhost 5555``, you 2649 connect to the guest telnet server. 2650 2651 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2652 Forward guest TCP connections to the IP address server on port 2653 port to the character device dev or to a program executed by 2654 cmd:command which gets spawned for each connection. This option 2655 can be given multiple times. 2656 2657 You can either use a chardev directly and have that one used 2658 throughout QEMU's lifetime, like in the following example: 2659 2660 .. parsed-literal:: 2661 2662 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2663 # the guest accesses it 2664 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2665 2666 Or you can execute a command on every TCP connection established 2667 by the guest, so that QEMU behaves similar to an inetd process 2668 for that virtual server: 2669 2670 .. parsed-literal:: 2671 2672 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2673 # and connect the TCP stream to its stdin/stdout 2674 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2675 2676``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2677 Configure a host TAP network backend with ID id. 2678 2679 Use the network script file to configure it and the network script 2680 dfile to deconfigure it. If name is not provided, the OS 2681 automatically provides one. The default network configure script is 2682 ``/etc/qemu-ifup`` and the default network deconfigure script is 2683 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2684 disable script execution. 2685 2686 If running QEMU as an unprivileged user, use the network helper 2687 helper to configure the TAP interface and attach it to the bridge. 2688 The default network helper executable is 2689 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2690 ``br0``. 2691 2692 ``fd``\ =h can be used to specify the handle of an already opened 2693 host TAP interface. 2694 2695 Examples: 2696 2697 .. parsed-literal:: 2698 2699 #launch a QEMU instance with the default network script 2700 |qemu_system| linux.img -nic tap 2701 2702 .. parsed-literal:: 2703 2704 #launch a QEMU instance with two NICs, each one connected 2705 #to a TAP device 2706 |qemu_system| linux.img \ 2707 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \ 2708 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2709 2710 .. parsed-literal:: 2711 2712 #launch a QEMU instance with the default network helper to 2713 #connect a TAP device to bridge br0 2714 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \ 2715 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2716 2717``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2718 Connect a host TAP network interface to a host bridge device. 2719 2720 Use the network helper helper to configure the TAP interface and 2721 attach it to the bridge. The default network helper executable is 2722 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2723 ``br0``. 2724 2725 Examples: 2726 2727 .. parsed-literal:: 2728 2729 #launch a QEMU instance with the default network helper to 2730 #connect a TAP device to bridge br0 2731 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2732 2733 .. parsed-literal:: 2734 2735 #launch a QEMU instance with the default network helper to 2736 #connect a TAP device to bridge qemubr0 2737 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2738 2739``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2740 This host network backend can be used to connect the guest's network 2741 to another QEMU virtual machine using a TCP socket connection. If 2742 ``listen`` is specified, QEMU waits for incoming connections on port 2743 (host is optional). ``connect`` is used to connect to another QEMU 2744 instance using the ``listen`` option. ``fd``\ =h specifies an 2745 already opened TCP socket. 2746 2747 Example: 2748 2749 .. parsed-literal:: 2750 2751 # launch a first QEMU instance 2752 |qemu_system| linux.img \ 2753 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2754 -netdev socket,id=n1,listen=:1234 2755 # connect the network of this instance to the network of the first instance 2756 |qemu_system| linux.img \ 2757 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \ 2758 -netdev socket,id=n2,connect=127.0.0.1:1234 2759 2760``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2761 Configure a socket host network backend to share the guest's network 2762 traffic with another QEMU virtual machines using a UDP multicast 2763 socket, effectively making a bus for every QEMU with same multicast 2764 address maddr and port. NOTES: 2765 2766 1. Several QEMU can be running on different hosts and share same bus 2767 (assuming correct multicast setup for these hosts). 2768 2769 2. mcast support is compatible with User Mode Linux (argument 2770 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2771 2772 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2773 2774 Example: 2775 2776 .. parsed-literal:: 2777 2778 # launch one QEMU instance 2779 |qemu_system| linux.img \ 2780 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2781 -netdev socket,id=n1,mcast=230.0.0.1:1234 2782 # launch another QEMU instance on same "bus" 2783 |qemu_system| linux.img \ 2784 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \ 2785 -netdev socket,id=n2,mcast=230.0.0.1:1234 2786 # launch yet another QEMU instance on same "bus" 2787 |qemu_system| linux.img \ 2788 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \ 2789 -netdev socket,id=n3,mcast=230.0.0.1:1234 2790 2791 Example (User Mode Linux compat.): 2792 2793 .. parsed-literal:: 2794 2795 # launch QEMU instance (note mcast address selected is UML's default) 2796 |qemu_system| linux.img \ 2797 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2798 -netdev socket,id=n1,mcast=239.192.168.1:1102 2799 # launch UML 2800 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2801 2802 Example (send packets from host's 1.2.3.4): 2803 2804 .. parsed-literal:: 2805 2806 |qemu_system| linux.img \ 2807 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \ 2808 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2809 2810``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6][,udp][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2811 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2812 is a popular protocol to transport Ethernet (and other Layer 2) data 2813 frames between two systems. It is present in routers, firewalls and 2814 the Linux kernel (from version 3.3 onwards). 2815 2816 This transport allows a VM to communicate to another VM, router or 2817 firewall directly. 2818 2819 ``src=srcaddr`` 2820 source address (mandatory) 2821 2822 ``dst=dstaddr`` 2823 destination address (mandatory) 2824 2825 ``udp`` 2826 select udp encapsulation (default is ip). 2827 2828 ``srcport=srcport`` 2829 source udp port. 2830 2831 ``dstport=dstport`` 2832 destination udp port. 2833 2834 ``ipv6`` 2835 force v6, otherwise defaults to v4. 2836 2837 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2838 Cookies are a weak form of security in the l2tpv3 specification. 2839 Their function is mostly to prevent misconfiguration. By default 2840 they are 32 bit. 2841 2842 ``cookie64`` 2843 Set cookie size to 64 bit instead of the default 32 2844 2845 ``counter=off`` 2846 Force a 'cut-down' L2TPv3 with no counter as in 2847 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2848 2849 ``pincounter=on`` 2850 Work around broken counter handling in peer. This may also help 2851 on networks which have packet reorder. 2852 2853 ``offset=offset`` 2854 Add an extra offset between header and data 2855 2856 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 2857 the bridge br-lan on the remote Linux host 1.2.3.4: 2858 2859 .. parsed-literal:: 2860 2861 # Setup tunnel on linux host using raw ip as encapsulation 2862 # on 1.2.3.4 2863 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \ 2864 encap udp udp_sport 16384 udp_dport 16384 2865 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \ 2866 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2867 ifconfig vmtunnel0 mtu 1500 2868 ifconfig vmtunnel0 up 2869 brctl addif br-lan vmtunnel0 2870 2871 2872 # on 4.3.2.1 2873 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2874 2875 |qemu_system| linux.img -device e1000,netdev=n1 \ 2876 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2877 2878``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 2879 Configure VDE backend to connect to PORT n of a vde switch running 2880 on host and listening for incoming connections on socketpath. Use 2881 GROUP groupname and MODE octalmode to change default ownership and 2882 permissions for communication port. This option is only available if 2883 QEMU has been compiled with vde support enabled. 2884 2885 Example: 2886 2887 .. parsed-literal:: 2888 2889 # launch vde switch 2890 vde_switch -F -sock /tmp/myswitch 2891 # launch QEMU instance 2892 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 2893 2894``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 2895 Establish a vhost-user netdev, backed by a chardev id. The chardev 2896 should be a unix domain socket backed one. The vhost-user uses a 2897 specifically defined protocol to pass vhost ioctl replacement 2898 messages to an application on the other end of the socket. On 2899 non-MSIX guests, the feature can be forced with vhostforce. Use 2900 'queues=n' to specify the number of queues to be created for 2901 multiqueue vhost-user. 2902 2903 Example: 2904 2905 :: 2906 2907 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 2908 -numa node,memdev=mem \ 2909 -chardev socket,id=chr0,path=/path/to/socket \ 2910 -netdev type=vhost-user,id=net0,chardev=chr0 \ 2911 -device virtio-net-pci,netdev=net0 2912 2913``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 2914 Establish a vhost-vdpa netdev. 2915 2916 vDPA device is a device that uses a datapath which complies with 2917 the virtio specifications with a vendor specific control path. 2918 vDPA devices can be both physically located on the hardware or 2919 emulated by software. 2920 2921``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 2922 Create a hub port on the emulated hub with ID hubid. 2923 2924 The hubport netdev lets you connect a NIC to a QEMU emulated hub 2925 instead of a single netdev. Alternatively, you can also connect the 2926 hubport to another netdev with ID nd by using the ``netdev=nd`` 2927 option. 2928 2929``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 2930 Legacy option to configure or create an on-board (or machine 2931 default) Network Interface Card(NIC) and connect it either to the 2932 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 2933 If model is omitted, then the default NIC model associated with the 2934 machine type is used. Note that the default NIC model may change in 2935 future QEMU releases, so it is highly recommended to always specify 2936 a model. Optionally, the MAC address can be changed to mac, the 2937 device address set to addr (PCI cards only), and a name can be 2938 assigned for use in monitor commands. Optionally, for PCI cards, you 2939 can specify the number v of MSI-X vectors that the card should have; 2940 this option currently only affects virtio cards; set v = 0 to 2941 disable MSI-X. If no ``-net`` option is specified, a single NIC is 2942 created. QEMU can emulate several different models of network card. 2943 Use ``-net nic,model=help`` for a list of available devices for your 2944 target. 2945 2946``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 2947 Configure a host network backend (with the options corresponding to 2948 the same ``-netdev`` option) and connect it to the emulated hub 0 2949 (the default hub). Use name to specify the name of the hub port. 2950ERST 2951 2952DEFHEADING() 2953 2954DEFHEADING(Character device options:) 2955 2956DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 2957 "-chardev help\n" 2958 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2959 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n" 2960 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n" 2961 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 2962 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n" 2963 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 2964 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 2965 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n" 2966 " [,logfile=PATH][,logappend=on|off]\n" 2967 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2968 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 2969 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2970 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 2971 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2972 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2973#ifdef _WIN32 2974 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2975 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2976#else 2977 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2978 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 2979#endif 2980#ifdef CONFIG_BRLAPI 2981 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2982#endif 2983#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 2984 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 2985 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2986 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2987#endif 2988#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 2989 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2990 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 2991#endif 2992#if defined(CONFIG_SPICE) 2993 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 2994 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 2995#endif 2996 , QEMU_ARCH_ALL 2997) 2998 2999SRST 3000The general form of a character device option is: 3001 3002``-chardev backend,id=id[,mux=on|off][,options]`` 3003 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3004 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3005 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3006 ``spicevmc``, ``spiceport``. The specific backend will determine the 3007 applicable options. 3008 3009 Use ``-chardev help`` to print all available chardev backend types. 3010 3011 All devices must have an id, which can be any string up to 127 3012 characters long. It is used to uniquely identify this device in 3013 other command line directives. 3014 3015 A character device may be used in multiplexing mode by multiple 3016 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3017 a "1:N" device, and here the "1" end is your specified chardev 3018 backend, and the "N" end is the various parts of QEMU that can talk 3019 to a chardev. If you create a chardev with ``id=myid`` and 3020 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3021 and you can then configure multiple front ends to use that chardev 3022 ID for their input/output. Up to four different front ends can be 3023 connected to a single multiplexed chardev. (Without multiplexing 3024 enabled, a chardev can only be used by a single front end.) For 3025 instance you could use this to allow a single stdio chardev to be 3026 used by two serial ports and the QEMU monitor: 3027 3028 :: 3029 3030 -chardev stdio,mux=on,id=char0 \ 3031 -mon chardev=char0,mode=readline \ 3032 -serial chardev:char0 \ 3033 -serial chardev:char0 3034 3035 You can have more than one multiplexer in a system configuration; 3036 for instance you could have a TCP port multiplexed between UART 0 3037 and UART 1, and stdio multiplexed between the QEMU monitor and a 3038 parallel port: 3039 3040 :: 3041 3042 -chardev stdio,mux=on,id=char0 \ 3043 -mon chardev=char0,mode=readline \ 3044 -parallel chardev:char0 \ 3045 -chardev tcp,...,mux=on,id=char1 \ 3046 -serial chardev:char1 \ 3047 -serial chardev:char1 3048 3049 When you're using a multiplexed character device, some escape 3050 sequences are interpreted in the input. See :ref:`mux_005fkeys`. 3051 3052 Note that some other command line options may implicitly create 3053 multiplexed character backends; for instance ``-serial mon:stdio`` 3054 creates a multiplexed stdio backend connected to the serial port and 3055 the QEMU monitor, and ``-nographic`` also multiplexes the console 3056 and the monitor to stdio. 3057 3058 There is currently no support for multiplexing in the other 3059 direction (where a single QEMU front end takes input and output from 3060 multiple chardevs). 3061 3062 Every backend supports the ``logfile`` option, which supplies the 3063 path to a file to record all data transmitted via the backend. The 3064 ``logappend`` option controls whether the log file will be truncated 3065 or appended to when opened. 3066 3067The available backends are: 3068 3069``-chardev null,id=id`` 3070 A void device. This device will not emit any data, and will drop any 3071 data it receives. The null backend does not take any options. 3072 3073``-chardev socket,id=id[,TCP options or unix options][,server][,nowait][,telnet][,websocket][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3074 Create a two-way stream socket, which can be either a TCP or a unix 3075 socket. A unix socket will be created if ``path`` is specified. 3076 Behaviour is undefined if TCP options are specified for a unix 3077 socket. 3078 3079 ``server`` specifies that the socket shall be a listening socket. 3080 3081 ``nowait`` specifies that QEMU should not block waiting for a client 3082 to connect to a listening socket. 3083 3084 ``telnet`` specifies that traffic on the socket should interpret 3085 telnet escape sequences. 3086 3087 ``websocket`` specifies that the socket uses WebSocket protocol for 3088 communication. 3089 3090 ``reconnect`` sets the timeout for reconnecting on non-server 3091 sockets when the remote end goes away. qemu will delay this many 3092 seconds and then attempt to reconnect. Zero disables reconnecting, 3093 and is the default. 3094 3095 ``tls-creds`` requests enablement of the TLS protocol for 3096 encryption, and specifies the id of the TLS credentials to use for 3097 the handshake. The credentials must be previously created with the 3098 ``-object tls-creds`` argument. 3099 3100 ``tls-auth`` provides the ID of the QAuthZ authorization object 3101 against which the client's x509 distinguished name will be 3102 validated. This object is only resolved at time of use, so can be 3103 deleted and recreated on the fly while the chardev server is active. 3104 If missing, it will default to denying access. 3105 3106 TCP and unix socket options are given below: 3107 3108 ``TCP options: port=port[,host=host][,to=to][,ipv4][,ipv6][,nodelay]`` 3109 ``host`` for a listening socket specifies the local address to 3110 be bound. For a connecting socket species the remote host to 3111 connect to. ``host`` is optional for listening sockets. If not 3112 specified it defaults to ``0.0.0.0``. 3113 3114 ``port`` for a listening socket specifies the local port to be 3115 bound. For a connecting socket specifies the port on the remote 3116 host to connect to. ``port`` can be given as either a port 3117 number or a service name. ``port`` is required. 3118 3119 ``to`` is only relevant to listening sockets. If it is 3120 specified, and ``port`` cannot be bound, QEMU will attempt to 3121 bind to subsequent ports up to and including ``to`` until it 3122 succeeds. ``to`` must be specified as a port number. 3123 3124 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be 3125 used. If neither is specified the socket may use either 3126 protocol. 3127 3128 ``nodelay`` disables the Nagle algorithm. 3129 3130 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3131 ``path`` specifies the local path of the unix socket. ``path`` 3132 is required. 3133 ``abstract`` specifies the use of the abstract socket namespace, 3134 rather than the filesystem. Optional, defaults to false. 3135 ``tight`` sets the socket length of abstract sockets to their minimum, 3136 rather than the full sun_path length. Optional, defaults to true. 3137 3138``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4][,ipv6]`` 3139 Sends all traffic from the guest to a remote host over UDP. 3140 3141 ``host`` specifies the remote host to connect to. If not specified 3142 it defaults to ``localhost``. 3143 3144 ``port`` specifies the port on the remote host to connect to. 3145 ``port`` is required. 3146 3147 ``localaddr`` specifies the local address to bind to. If not 3148 specified it defaults to ``0.0.0.0``. 3149 3150 ``localport`` specifies the local port to bind to. If not specified 3151 any available local port will be used. 3152 3153 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be used. 3154 If neither is specified the device may use either protocol. 3155 3156``-chardev msmouse,id=id`` 3157 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3158 does not take any options. 3159 3160``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3161 Connect to a QEMU text console. ``vc`` may optionally be given a 3162 specific size. 3163 3164 ``width`` and ``height`` specify the width and height respectively 3165 of the console, in pixels. 3166 3167 ``cols`` and ``rows`` specify that the console be sized to fit a 3168 text console with the given dimensions. 3169 3170``-chardev ringbuf,id=id[,size=size]`` 3171 Create a ring buffer with fixed size ``size``. size must be a power 3172 of two and defaults to ``64K``. 3173 3174``-chardev file,id=id,path=path`` 3175 Log all traffic received from the guest to a file. 3176 3177 ``path`` specifies the path of the file to be opened. This file will 3178 be created if it does not already exist, and overwritten if it does. 3179 ``path`` is required. 3180 3181``-chardev pipe,id=id,path=path`` 3182 Create a two-way connection to the guest. The behaviour differs 3183 slightly between Windows hosts and other hosts: 3184 3185 On Windows, a single duplex pipe will be created at 3186 ``\\.pipe\path``. 3187 3188 On other hosts, 2 pipes will be created called ``path.in`` and 3189 ``path.out``. Data written to ``path.in`` will be received by the 3190 guest. Data written by the guest can be read from ``path.out``. QEMU 3191 will not create these fifos, and requires them to be present. 3192 3193 ``path`` forms part of the pipe path as described above. ``path`` is 3194 required. 3195 3196``-chardev console,id=id`` 3197 Send traffic from the guest to QEMU's standard output. ``console`` 3198 does not take any options. 3199 3200 ``console`` is only available on Windows hosts. 3201 3202``-chardev serial,id=id,path=path`` 3203 Send traffic from the guest to a serial device on the host. 3204 3205 On Unix hosts serial will actually accept any tty device, not only 3206 serial lines. 3207 3208 ``path`` specifies the name of the serial device to open. 3209 3210``-chardev pty,id=id`` 3211 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3212 does not take any options. 3213 3214 ``pty`` is not available on Windows hosts. 3215 3216``-chardev stdio,id=id[,signal=on|off]`` 3217 Connect to standard input and standard output of the QEMU process. 3218 3219 ``signal`` controls if signals are enabled on the terminal, that 3220 includes exiting QEMU with the key sequence Control-c. This option 3221 is enabled by default, use ``signal=off`` to disable it. 3222 3223``-chardev braille,id=id`` 3224 Connect to a local BrlAPI server. ``braille`` does not take any 3225 options. 3226 3227``-chardev tty,id=id,path=path`` 3228 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3229 and DragonFlyBSD hosts. It is an alias for ``serial``. 3230 3231 ``path`` specifies the path to the tty. ``path`` is required. 3232 3233``-chardev parallel,id=id,path=path`` 3234 \ 3235``-chardev parport,id=id,path=path`` 3236 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3237 hosts. 3238 3239 Connect to a local parallel port. 3240 3241 ``path`` specifies the path to the parallel port device. ``path`` is 3242 required. 3243 3244``-chardev spicevmc,id=id,debug=debug,name=name`` 3245 ``spicevmc`` is only available when spice support is built in. 3246 3247 ``debug`` debug level for spicevmc 3248 3249 ``name`` name of spice channel to connect to 3250 3251 Connect to a spice virtual machine channel, such as vdiport. 3252 3253``-chardev spiceport,id=id,debug=debug,name=name`` 3254 ``spiceport`` is only available when spice support is built in. 3255 3256 ``debug`` debug level for spicevmc 3257 3258 ``name`` name of spice port to connect to 3259 3260 Connect to a spice port, allowing a Spice client to handle the 3261 traffic identified by a name (preferably a fqdn). 3262ERST 3263 3264DEFHEADING() 3265 3266#ifdef CONFIG_TPM 3267DEFHEADING(TPM device options:) 3268 3269DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3270 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3271 " use path to provide path to a character device; default is /dev/tpm0\n" 3272 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3273 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3274 "-tpmdev emulator,id=id,chardev=dev\n" 3275 " configure the TPM device using chardev backend\n", 3276 QEMU_ARCH_ALL) 3277SRST 3278The general form of a TPM device option is: 3279 3280``-tpmdev backend,id=id[,options]`` 3281 The specific backend type will determine the applicable options. The 3282 ``-tpmdev`` option creates the TPM backend and requires a 3283 ``-device`` option that specifies the TPM frontend interface model. 3284 3285 Use ``-tpmdev help`` to print all available TPM backend types. 3286 3287The available backends are: 3288 3289``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3290 (Linux-host only) Enable access to the host's TPM using the 3291 passthrough driver. 3292 3293 ``path`` specifies the path to the host's TPM device, i.e., on a 3294 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3295 default ``/dev/tpm0`` is used. 3296 3297 ``cancel-path`` specifies the path to the host TPM device's sysfs 3298 entry allowing for cancellation of an ongoing TPM command. 3299 ``cancel-path`` is optional and by default QEMU will search for the 3300 sysfs entry to use. 3301 3302 Some notes about using the host's TPM with the passthrough driver: 3303 3304 The TPM device accessed by the passthrough driver must not be used 3305 by any other application on the host. 3306 3307 Since the host's firmware (BIOS/UEFI) has already initialized the 3308 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3309 the TPM again and may therefore not show a TPM-specific menu that 3310 would otherwise allow the user to configure the TPM, e.g., allow the 3311 user to enable/disable or activate/deactivate the TPM. Further, if 3312 TPM ownership is released from within a VM then the host's TPM will 3313 get disabled and deactivated. To enable and activate the TPM again 3314 afterwards, the host has to be rebooted and the user is required to 3315 enter the firmware's menu to enable and activate the TPM. If the TPM 3316 is left disabled and/or deactivated most TPM commands will fail. 3317 3318 To create a passthrough TPM use the following two options: 3319 3320 :: 3321 3322 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3323 3324 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3325 ``tpmdev=tpm0`` in the device option. 3326 3327``-tpmdev emulator,id=id,chardev=dev`` 3328 (Linux-host only) Enable access to a TPM emulator using Unix domain 3329 socket based chardev backend. 3330 3331 ``chardev`` specifies the unique ID of a character device backend 3332 that provides connection to the software TPM server. 3333 3334 To create a TPM emulator backend device with chardev socket backend: 3335 3336 :: 3337 3338 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3339ERST 3340 3341DEFHEADING() 3342 3343#endif 3344 3345DEFHEADING(Linux/Multiboot boot specific:) 3346SRST 3347When using these options, you can use a given Linux or Multiboot kernel 3348without installing it in the disk image. It can be useful for easier 3349testing of various kernels. 3350 3351 3352ERST 3353 3354DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3355 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3356SRST 3357``-kernel bzImage`` 3358 Use bzImage as kernel image. The kernel can be either a Linux kernel 3359 or in multiboot format. 3360ERST 3361 3362DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3363 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3364SRST 3365``-append cmdline`` 3366 Use cmdline as kernel command line 3367ERST 3368 3369DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3370 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3371SRST 3372``-initrd file`` 3373 Use file as initial ram disk. 3374 3375``-initrd "file1 arg=foo,file2"`` 3376 This syntax is only available with multiboot. 3377 3378 Use file1 and file2 as modules and pass arg=foo as parameter to the 3379 first module. 3380ERST 3381 3382DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3383 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3384SRST 3385``-dtb file`` 3386 Use file as a device tree binary (dtb) image and pass it to the 3387 kernel on boot. 3388ERST 3389 3390DEFHEADING() 3391 3392DEFHEADING(Debug/Expert options:) 3393 3394DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3395 "-fw_cfg [name=]<name>,file=<file>\n" 3396 " add named fw_cfg entry with contents from file\n" 3397 "-fw_cfg [name=]<name>,string=<str>\n" 3398 " add named fw_cfg entry with contents from string\n", 3399 QEMU_ARCH_ALL) 3400SRST 3401``-fw_cfg [name=]name,file=file`` 3402 Add named fw\_cfg entry with contents from file file. 3403 3404``-fw_cfg [name=]name,string=str`` 3405 Add named fw\_cfg entry with contents from string str. 3406 3407 The terminating NUL character of the contents of str will not be 3408 included as part of the fw\_cfg item data. To insert contents with 3409 embedded NUL characters, you have to use the file parameter. 3410 3411 The fw\_cfg entries are passed by QEMU through to the guest. 3412 3413 Example: 3414 3415 :: 3416 3417 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3418 3419 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3420 from ./my\_blob.bin. 3421ERST 3422 3423DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3424 "-serial dev redirect the serial port to char device 'dev'\n", 3425 QEMU_ARCH_ALL) 3426SRST 3427``-serial dev`` 3428 Redirect the virtual serial port to host character device dev. The 3429 default device is ``vc`` in graphical mode and ``stdio`` in non 3430 graphical mode. 3431 3432 This option can be used several times to simulate up to 4 serial 3433 ports. 3434 3435 Use ``-serial none`` to disable all serial ports. 3436 3437 Available character devices are: 3438 3439 ``vc[:WxH]`` 3440 Virtual console. Optionally, a width and height can be given in 3441 pixel with 3442 3443 :: 3444 3445 vc:800x600 3446 3447 It is also possible to specify width or height in characters: 3448 3449 :: 3450 3451 vc:80Cx24C 3452 3453 ``pty`` 3454 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3455 3456 ``none`` 3457 No device is allocated. 3458 3459 ``null`` 3460 void device 3461 3462 ``chardev:id`` 3463 Use a named character device defined with the ``-chardev`` 3464 option. 3465 3466 ``/dev/XXX`` 3467 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3468 port parameters are set according to the emulated ones. 3469 3470 ``/dev/parportN`` 3471 [Linux only, parallel port only] Use host parallel port N. 3472 Currently SPP and EPP parallel port features can be used. 3473 3474 ``file:filename`` 3475 Write output to filename. No character can be read. 3476 3477 ``stdio`` 3478 [Unix only] standard input/output 3479 3480 ``pipe:filename`` 3481 name pipe filename 3482 3483 ``COMn`` 3484 [Windows only] Use host serial port n 3485 3486 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3487 This implements UDP Net Console. When remote\_host or src\_ip 3488 are not specified they default to ``0.0.0.0``. When not using a 3489 specified src\_port a random port is automatically chosen. 3490 3491 If you just want a simple readonly console you can use 3492 ``netcat`` or ``nc``, by starting QEMU with: 3493 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3494 QEMU writes something to that port it will appear in the 3495 netconsole session. 3496 3497 If you plan to send characters back via netconsole or you want 3498 to stop and start QEMU a lot of times, you should have QEMU use 3499 the same source port each time by using something like ``-serial 3500 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3501 version of netcat which can listen to a TCP port and send and 3502 receive characters via udp. If you have a patched version of 3503 netcat which activates telnet remote echo and single char 3504 transfer, then you can use the following options to set up a 3505 netcat redirector to allow telnet on port 5555 to access the 3506 QEMU port. 3507 3508 ``QEMU Options:`` 3509 -serial udp::4555@:4556 3510 3511 ``netcat options:`` 3512 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3513 3514 ``telnet options:`` 3515 localhost 5555 3516 3517 ``tcp:[host]:port[,server][,nowait][,nodelay][,reconnect=seconds]`` 3518 The TCP Net Console has two modes of operation. It can send the 3519 serial I/O to a location or wait for a connection from a 3520 location. By default the TCP Net Console is sent to host at the 3521 port. If you use the server option QEMU will wait for a client 3522 socket application to connect to the port before continuing, 3523 unless the ``nowait`` option was specified. The ``nodelay`` 3524 option disables the Nagle buffering algorithm. The ``reconnect`` 3525 option only applies if noserver is set, if the connection goes 3526 down it will attempt to reconnect at the given interval. If host 3527 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3528 time is accepted. You can use ``telnet`` to connect to the 3529 corresponding character device. 3530 3531 ``Example to send tcp console to 192.168.0.2 port 4444`` 3532 -serial tcp:192.168.0.2:4444 3533 3534 ``Example to listen and wait on port 4444 for connection`` 3535 -serial tcp::4444,server 3536 3537 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3538 -serial tcp:192.168.0.100:4444,server,nowait 3539 3540 ``telnet:host:port[,server][,nowait][,nodelay]`` 3541 The telnet protocol is used instead of raw tcp sockets. The 3542 options work the same as if you had specified ``-serial tcp``. 3543 The difference is that the port acts like a telnet server or 3544 client using telnet option negotiation. This will also allow you 3545 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3546 supports sending the break sequence. Typically in unix telnet 3547 you do it with Control-] and then type "send break" followed by 3548 pressing the enter key. 3549 3550 ``websocket:host:port,server[,nowait][,nodelay]`` 3551 The WebSocket protocol is used instead of raw tcp socket. The 3552 port acts as a WebSocket server. Client mode is not supported. 3553 3554 ``unix:path[,server][,nowait][,reconnect=seconds]`` 3555 A unix domain socket is used instead of a tcp socket. The option 3556 works the same as if you had specified ``-serial tcp`` except 3557 the unix domain socket path is used for connections. 3558 3559 ``mon:dev_string`` 3560 This is a special option to allow the monitor to be multiplexed 3561 onto another serial port. The monitor is accessed with key 3562 sequence of Control-a and then pressing c. dev\_string should be 3563 any one of the serial devices specified above. An example to 3564 multiplex the monitor onto a telnet server listening on port 3565 4444 would be: 3566 3567 ``-serial mon:telnet::4444,server,nowait`` 3568 3569 When the monitor is multiplexed to stdio in this way, Ctrl+C 3570 will not terminate QEMU any more but will be passed to the guest 3571 instead. 3572 3573 ``braille`` 3574 Braille device. This will use BrlAPI to display the braille 3575 output on a real or fake device. 3576 3577 ``msmouse`` 3578 Three button serial mouse. Configure the guest to use Microsoft 3579 protocol. 3580ERST 3581 3582DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3583 "-parallel dev redirect the parallel port to char device 'dev'\n", 3584 QEMU_ARCH_ALL) 3585SRST 3586``-parallel dev`` 3587 Redirect the virtual parallel port to host device dev (same devices 3588 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3589 to use hardware devices connected on the corresponding host parallel 3590 port. 3591 3592 This option can be used several times to simulate up to 3 parallel 3593 ports. 3594 3595 Use ``-parallel none`` to disable all parallel ports. 3596ERST 3597 3598DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3599 "-monitor dev redirect the monitor to char device 'dev'\n", 3600 QEMU_ARCH_ALL) 3601SRST 3602``-monitor dev`` 3603 Redirect the monitor to host device dev (same devices as the serial 3604 port). The default device is ``vc`` in graphical mode and ``stdio`` 3605 in non graphical mode. Use ``-monitor none`` to disable the default 3606 monitor. 3607ERST 3608DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3609 "-qmp dev like -monitor but opens in 'control' mode\n", 3610 QEMU_ARCH_ALL) 3611SRST 3612``-qmp dev`` 3613 Like -monitor but opens in 'control' mode. 3614ERST 3615DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3616 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3617 QEMU_ARCH_ALL) 3618SRST 3619``-qmp-pretty dev`` 3620 Like -qmp but uses pretty JSON formatting. 3621ERST 3622 3623DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3624 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3625SRST 3626``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3627 Setup monitor on chardev name. ``pretty`` turns on JSON pretty 3628 printing easing human reading and debugging. 3629ERST 3630 3631DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3632 "-debugcon dev redirect the debug console to char device 'dev'\n", 3633 QEMU_ARCH_ALL) 3634SRST 3635``-debugcon dev`` 3636 Redirect the debug console to host device dev (same devices as the 3637 serial port). The debug console is an I/O port which is typically 3638 port 0xe9; writing to that I/O port sends output to this device. The 3639 default device is ``vc`` in graphical mode and ``stdio`` in non 3640 graphical mode. 3641ERST 3642 3643DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3644 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3645SRST 3646``-pidfile file`` 3647 Store the QEMU process PID in file. It is useful if you launch QEMU 3648 from a script. 3649ERST 3650 3651DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3652 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3653SRST 3654``-singlestep`` 3655 Run the emulation in single step mode. 3656ERST 3657 3658DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3659 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3660 QEMU_ARCH_ALL) 3661SRST 3662``--preconfig`` 3663 Pause QEMU for interactive configuration before the machine is 3664 created, which allows querying and configuring properties that will 3665 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3666 exit the preconfig state and move to the next state (i.e. run guest 3667 if -S isn't used or pause the second time if -S is used). This 3668 option is experimental. 3669ERST 3670 3671DEF("S", 0, QEMU_OPTION_S, \ 3672 "-S freeze CPU at startup (use 'c' to start execution)\n", 3673 QEMU_ARCH_ALL) 3674SRST 3675``-S`` 3676 Do not start CPU at startup (you must type 'c' in the monitor). 3677ERST 3678 3679DEF("realtime", HAS_ARG, QEMU_OPTION_realtime, 3680 "-realtime [mlock=on|off]\n" 3681 " run qemu with realtime features\n" 3682 " mlock=on|off controls mlock support (default: on)\n", 3683 QEMU_ARCH_ALL) 3684SRST 3685``-realtime mlock=on|off`` 3686 Run qemu with realtime features. mlocking qemu and guest memory can 3687 be enabled via ``mlock=on`` (enabled by default). 3688ERST 3689 3690DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3691 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3692 " run qemu with overcommit hints\n" 3693 " mem-lock=on|off controls memory lock support (default: off)\n" 3694 " cpu-pm=on|off controls cpu power management (default: off)\n", 3695 QEMU_ARCH_ALL) 3696SRST 3697``-overcommit mem-lock=on|off`` 3698 \ 3699``-overcommit cpu-pm=on|off`` 3700 Run qemu with hints about host resource overcommit. The default is 3701 to assume that host overcommits all resources. 3702 3703 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3704 (disabled by default). This works when host memory is not 3705 overcommitted and reduces the worst-case latency for guest. This is 3706 equivalent to ``realtime``. 3707 3708 Guest ability to manage power state of host cpus (increasing latency 3709 for other processes on the same host cpu, but decreasing latency for 3710 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3711 works best when host CPU is not overcommitted. When used, host 3712 estimates of CPU cycle and power utilization will be incorrect, not 3713 taking into account guest idle time. 3714ERST 3715 3716DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3717 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3718 " the guest without waiting for gdb to connect; use -S too\n" 3719 " if you want it to not start execution.)\n", 3720 QEMU_ARCH_ALL) 3721SRST 3722``-gdb dev`` 3723 Accept a gdb connection on device dev (see 3724 :ref:`gdb_005fusage`). Note that this option does not pause QEMU 3725 execution -- if you want QEMU to not start the guest until you 3726 connect with gdb and issue a ``continue`` command, you will need to 3727 also pass the ``-S`` option to QEMU. 3728 3729 The most usual configuration is to listen on a local TCP socket:: 3730 3731 -gdb tcp::3117 3732 3733 but you can specify other backends; UDP, pseudo TTY, or even stdio 3734 are all reasonable use cases. For example, a stdio connection 3735 allows you to start QEMU from within gdb and establish the 3736 connection via a pipe: 3737 3738 .. parsed-literal:: 3739 3740 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3741ERST 3742 3743DEF("s", 0, QEMU_OPTION_s, \ 3744 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3745 QEMU_ARCH_ALL) 3746SRST 3747``-s`` 3748 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3749 (see :ref:`gdb_005fusage`). 3750ERST 3751 3752DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3753 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3754 QEMU_ARCH_ALL) 3755SRST 3756``-d item1[,...]`` 3757 Enable logging of specified items. Use '-d help' for a list of log 3758 items. 3759ERST 3760 3761DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3762 "-D logfile output log to logfile (default stderr)\n", 3763 QEMU_ARCH_ALL) 3764SRST 3765``-D logfile`` 3766 Output log in logfile instead of to stderr 3767ERST 3768 3769DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3770 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3771 QEMU_ARCH_ALL) 3772SRST 3773``-dfilter range1[,...]`` 3774 Filter debug output to that relevant to a range of target addresses. 3775 The filter spec can be either start+size, start-size or start..end 3776 where start end and size are the addresses and sizes required. For 3777 example: 3778 3779 :: 3780 3781 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3782 3783 Will dump output for any code in the 0x1000 sized block starting at 3784 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3785 another 0x1000 sized block starting at 0xffffffc00005f000. 3786ERST 3787 3788DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3789 "-seed number seed the pseudo-random number generator\n", 3790 QEMU_ARCH_ALL) 3791SRST 3792``-seed number`` 3793 Force the guest to use a deterministic pseudo-random number 3794 generator, seeded with number. This does not affect crypto routines 3795 within the host. 3796ERST 3797 3798DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3799 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3800 QEMU_ARCH_ALL) 3801SRST 3802``-L path`` 3803 Set the directory for the BIOS, VGA BIOS and keymaps. 3804 3805 To list all the data directories, use ``-L help``. 3806ERST 3807 3808DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3809 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3810SRST 3811``-bios file`` 3812 Set the filename for the BIOS. 3813ERST 3814 3815DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3816 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3817SRST 3818``-enable-kvm`` 3819 Enable KVM full virtualization support. This option is only 3820 available if KVM support is enabled when compiling. 3821ERST 3822 3823DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3824 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3825DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3826 "-xen-attach attach to existing xen domain\n" 3827 " libxl will use this when starting QEMU\n", 3828 QEMU_ARCH_ALL) 3829DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3830 "-xen-domid-restrict restrict set of available xen operations\n" 3831 " to specified domain id. (Does not affect\n" 3832 " xenpv machine type).\n", 3833 QEMU_ARCH_ALL) 3834SRST 3835``-xen-domid id`` 3836 Specify xen guest domain id (XEN only). 3837 3838``-xen-attach`` 3839 Attach to existing xen domain. libxl will use this when starting 3840 QEMU (XEN only). Restrict set of available xen operations to 3841 specified domain id (XEN only). 3842ERST 3843 3844DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3845 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3846SRST 3847``-no-reboot`` 3848 Exit instead of rebooting. 3849ERST 3850 3851DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3852 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3853SRST 3854``-no-shutdown`` 3855 Don't exit QEMU on guest shutdown, but instead only stop the 3856 emulation. This allows for instance switching to monitor to commit 3857 changes to the disk image. 3858ERST 3859 3860DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3861 "-loadvm [tag|id]\n" \ 3862 " start right away with a saved state (loadvm in monitor)\n", 3863 QEMU_ARCH_ALL) 3864SRST 3865``-loadvm file`` 3866 Start right away with a saved state (``loadvm`` in monitor) 3867ERST 3868 3869#ifndef _WIN32 3870DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3871 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3872#endif 3873SRST 3874``-daemonize`` 3875 Daemonize the QEMU process after initialization. QEMU will not 3876 detach from standard IO until it is ready to receive connections on 3877 any of its devices. This option is a useful way for external 3878 programs to launch QEMU without having to cope with initialization 3879 race conditions. 3880ERST 3881 3882DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3883 "-option-rom rom load a file, rom, into the option ROM space\n", 3884 QEMU_ARCH_ALL) 3885SRST 3886``-option-rom file`` 3887 Load the contents of file as an option ROM. This option is useful to 3888 load things like EtherBoot. 3889ERST 3890 3891DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 3892 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 3893 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 3894 QEMU_ARCH_ALL) 3895 3896SRST 3897``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 3898 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 3899 the current UTC or local time, respectively. ``localtime`` is 3900 required for correct date in MS-DOS or Windows. To start at a 3901 specific point in time, provide datetime in the format 3902 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 3903 3904 By default the RTC is driven by the host system time. This allows 3905 using of the RTC as accurate reference clock inside the guest, 3906 specifically if the host time is smoothly following an accurate 3907 external reference clock, e.g. via NTP. If you want to isolate the 3908 guest time from the host, you can set ``clock`` to ``rt`` instead, 3909 which provides a host monotonic clock if host support it. To even 3910 prevent the RTC from progressing during suspension, you can set 3911 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 3912 recommended especially in icount mode in order to preserve 3913 determinism; however, note that in icount mode the speed of the 3914 virtual clock is variable and can in general differ from the host 3915 clock. 3916 3917 Enable ``driftfix`` (i386 targets only) if you experience time drift 3918 problems, specifically with Windows' ACPI HAL. This option will try 3919 to figure out how many timer interrupts were not processed by the 3920 Windows guest and will re-inject them. 3921ERST 3922 3923DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 3924 "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \ 3925 " enable virtual instruction counter with 2^N clock ticks per\n" \ 3926 " instruction, enable aligning the host and virtual clocks\n" \ 3927 " or disable real time cpu sleeping\n", QEMU_ARCH_ALL) 3928SRST 3929``-icount [shift=N|auto][,rr=record|replay,rrfile=filename,rrsnapshot=snapshot]`` 3930 Enable virtual instruction counter. The virtual cpu will execute one 3931 instruction every 2^N ns of virtual time. If ``auto`` is specified 3932 then the virtual cpu speed will be automatically adjusted to keep 3933 virtual time within a few seconds of real time. 3934 3935 When the virtual cpu is sleeping, the virtual time will advance at 3936 default speed unless ``sleep=on|off`` is specified. With 3937 ``sleep=on|off``, the virtual time will jump to the next timer 3938 deadline instantly whenever the virtual cpu goes to sleep mode and 3939 will not advance if no timer is enabled. This behavior give 3940 deterministic execution times from the guest point of view. 3941 3942 Note that while this option can give deterministic behavior, it does 3943 not provide cycle accurate emulation. Modern CPUs contain 3944 superscalar out of order cores with complex cache hierarchies. The 3945 number of instructions executed often has little or no correlation 3946 with actual performance. 3947 3948 ``align=on`` will activate the delay algorithm which will try to 3949 synchronise the host clock and the virtual clock. The goal is to 3950 have a guest running at the real frequency imposed by the shift 3951 option. Whenever the guest clock is behind the host clock and if 3952 ``align=on`` is specified then we print a message to the user to 3953 inform about the delay. Currently this option does not work when 3954 ``shift`` is ``auto``. Note: The sync algorithm will work for those 3955 shift values for which the guest clock runs ahead of the host clock. 3956 Typically this happens when the shift value is high (how high 3957 depends on the host machine). 3958 3959 When ``rr`` option is specified deterministic record/replay is 3960 enabled. Replay log is written into filename file in record mode and 3961 read from this file in replay mode. 3962 3963 Option rrsnapshot is used to create new vm snapshot named snapshot 3964 at the start of execution recording. In replay mode this option is 3965 used to load the initial VM state. 3966ERST 3967 3968DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 3969 "-watchdog model\n" \ 3970 " enable virtual hardware watchdog [default=none]\n", 3971 QEMU_ARCH_ALL) 3972SRST 3973``-watchdog model`` 3974 Create a virtual hardware watchdog device. Once enabled (by a guest 3975 action), the watchdog must be periodically polled by an agent inside 3976 the guest or else the guest will be restarted. Choose a model for 3977 which your guest has drivers. 3978 3979 The model is the model of hardware watchdog to emulate. Use 3980 ``-watchdog help`` to list available hardware models. Only one 3981 watchdog can be enabled for a guest. 3982 3983 The following models may be available: 3984 3985 ``ib700`` 3986 iBASE 700 is a very simple ISA watchdog with a single timer. 3987 3988 ``i6300esb`` 3989 Intel 6300ESB I/O controller hub is a much more featureful 3990 PCI-based dual-timer watchdog. 3991 3992 ``diag288`` 3993 A virtual watchdog for s390x backed by the diagnose 288 3994 hypercall (currently KVM only). 3995ERST 3996 3997DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 3998 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 3999 " action when watchdog fires [default=reset]\n", 4000 QEMU_ARCH_ALL) 4001SRST 4002``-watchdog-action action`` 4003 The action controls what QEMU will do when the watchdog timer 4004 expires. The default is ``reset`` (forcefully reset the guest). 4005 Other possible actions are: ``shutdown`` (attempt to gracefully 4006 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4007 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4008 guest), ``debug`` (print a debug message and continue), or ``none`` 4009 (do nothing). 4010 4011 Note that the ``shutdown`` action requires that the guest responds 4012 to ACPI signals, which it may not be able to do in the sort of 4013 situations where the watchdog would have expired, and thus 4014 ``-watchdog-action shutdown`` is not recommended for production use. 4015 4016 Examples: 4017 4018 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4019 4020ERST 4021 4022DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4023 "-echr chr set terminal escape character instead of ctrl-a\n", 4024 QEMU_ARCH_ALL) 4025SRST 4026``-echr numeric_ascii_value`` 4027 Change the escape character used for switching to the monitor when 4028 using monitor and serial sharing. The default is ``0x01`` when using 4029 the ``-nographic`` option. ``0x01`` is equal to pressing 4030 ``Control-a``. You can select a different character from the ascii 4031 control keys where 1 through 26 map to Control-a through Control-z. 4032 For instance you could use the either of the following to change the 4033 escape character to Control-t. 4034 4035 ``-echr 0x14``; \ ``-echr 20`` 4036 4037ERST 4038 4039DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \ 4040 "-show-cursor show cursor\n", QEMU_ARCH_ALL) 4041SRST 4042``-show-cursor`` 4043 Show cursor. 4044ERST 4045 4046DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \ 4047 "-tb-size n set TB size\n", QEMU_ARCH_ALL) 4048SRST 4049``-tb-size n`` 4050 Set TCG translation block cache size. Deprecated, use 4051 '\ ``-accel tcg,tb-size=n``\ ' instead. 4052ERST 4053 4054DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4055 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \ 4056 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \ 4057 "-incoming unix:socketpath\n" \ 4058 " prepare for incoming migration, listen on\n" \ 4059 " specified protocol and socket address\n" \ 4060 "-incoming fd:fd\n" \ 4061 "-incoming exec:cmdline\n" \ 4062 " accept incoming migration on given file descriptor\n" \ 4063 " or from given external command\n" \ 4064 "-incoming defer\n" \ 4065 " wait for the URI to be specified via migrate_incoming\n", 4066 QEMU_ARCH_ALL) 4067SRST 4068``-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]`` 4069 \ 4070``-incoming rdma:host:port[,ipv4][,ipv6]`` 4071 Prepare for incoming migration, listen on a given tcp port. 4072 4073``-incoming unix:socketpath`` 4074 Prepare for incoming migration, listen on a given unix socket. 4075 4076``-incoming fd:fd`` 4077 Accept incoming migration from a given filedescriptor. 4078 4079``-incoming exec:cmdline`` 4080 Accept incoming migration as an output from specified external 4081 command. 4082 4083``-incoming defer`` 4084 Wait for the URI to be specified via migrate\_incoming. The monitor 4085 can be used to change settings (such as migration parameters) prior 4086 to issuing the migrate\_incoming to allow the migration to begin. 4087ERST 4088 4089DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4090 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4091SRST 4092``-only-migratable`` 4093 Only allow migratable devices. Devices will not be allowed to enter 4094 an unmigratable state. 4095ERST 4096 4097DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4098 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4099SRST 4100``-nodefaults`` 4101 Don't create default devices. Normally, QEMU sets the default 4102 devices like serial port, parallel port, virtual console, monitor 4103 device, VGA adapter, floppy and CD-ROM drive and others. The 4104 ``-nodefaults`` option will disable all those default devices. 4105ERST 4106 4107#ifndef _WIN32 4108DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4109 "-chroot dir chroot to dir just before starting the VM\n", 4110 QEMU_ARCH_ALL) 4111#endif 4112SRST 4113``-chroot dir`` 4114 Immediately before starting guest execution, chroot to the specified 4115 directory. Especially useful in combination with -runas. 4116ERST 4117 4118#ifndef _WIN32 4119DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4120 "-runas user change to user id user just before starting the VM\n" \ 4121 " user can be numeric uid:gid instead\n", 4122 QEMU_ARCH_ALL) 4123#endif 4124SRST 4125``-runas user`` 4126 Immediately before starting guest execution, drop root privileges, 4127 switching to the specified user. 4128ERST 4129 4130DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4131 "-prom-env variable=value\n" 4132 " set OpenBIOS nvram variables\n", 4133 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4134SRST 4135``-prom-env variable=value`` 4136 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4137 4138 :: 4139 4140 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4141 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4142 4143 :: 4144 4145 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4146 -prom-env 'boot-device=hd:2,\yaboot' \ 4147 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4148ERST 4149DEF("semihosting", 0, QEMU_OPTION_semihosting, 4150 "-semihosting semihosting mode\n", 4151 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4152 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2) 4153SRST 4154``-semihosting`` 4155 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only). 4156 4157 Note that this allows guest direct access to the host filesystem, so 4158 should only be used with a trusted guest OS. 4159 4160 See the -semihosting-config option documentation for further 4161 information about the facilities this enables. 4162ERST 4163DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4164 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4165 " semihosting configuration\n", 4166QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4167QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2) 4168SRST 4169``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4170 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II 4171 only). 4172 4173 Note that this allows guest direct access to the host filesystem, so 4174 should only be used with a trusted guest OS. 4175 4176 On Arm this implements the standard semihosting API, version 2.0. 4177 4178 On M68K this implements the "ColdFire GDB" interface used by 4179 libgloss. 4180 4181 Xtensa semihosting provides basic file IO calls, such as 4182 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4183 linux platform "sim" use this interface. 4184 4185 ``target=native|gdb|auto`` 4186 Defines where the semihosting calls will be addressed, to QEMU 4187 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4188 means ``gdb`` during debug sessions and ``native`` otherwise. 4189 4190 ``chardev=str1`` 4191 Send the output to a chardev backend output for native or auto 4192 output when not in gdb 4193 4194 ``arg=str1,arg=str2,...`` 4195 Allows the user to pass input arguments, and can be used 4196 multiple times to build up a list. The old-style 4197 ``-kernel``/``-append`` method of passing a command line is 4198 still supported for backward compatibility. If both the 4199 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4200 specified, the former is passed to semihosting as it always 4201 takes precedence. 4202ERST 4203DEF("old-param", 0, QEMU_OPTION_old_param, 4204 "-old-param old param mode\n", QEMU_ARCH_ARM) 4205SRST 4206``-old-param`` 4207 Old param mode (ARM only). 4208ERST 4209 4210DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4211 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4212 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4213 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4214 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4215 " by the kernel, but typically no longer used by modern\n" \ 4216 " C library implementations.\n" \ 4217 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \ 4218 " its privileges by blacklisting all set*uid|gid system calls.\n" \ 4219 " The value 'children' will deny set*uid|gid system calls for\n" \ 4220 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4221 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4222 " blacklisting *fork and execve\n" \ 4223 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4224 QEMU_ARCH_ALL) 4225SRST 4226``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4227 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4228 filtering and 'off' will disable it. The default is 'off'. 4229 4230 ``obsolete=string`` 4231 Enable Obsolete system calls 4232 4233 ``elevateprivileges=string`` 4234 Disable set\*uid\|gid system calls 4235 4236 ``spawn=string`` 4237 Disable \*fork and execve 4238 4239 ``resourcecontrol=string`` 4240 Disable process affinity and schedular priority 4241ERST 4242 4243DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4244 "-readconfig <file>\n", QEMU_ARCH_ALL) 4245SRST 4246``-readconfig file`` 4247 Read device configuration from file. This approach is useful when 4248 you want to spawn QEMU process with many command line options but 4249 you don't want to exceed the command line character limit. 4250ERST 4251DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4252 "-writeconfig <file>\n" 4253 " read/write config file\n", QEMU_ARCH_ALL) 4254SRST 4255``-writeconfig file`` 4256 Write device configuration to file. The file can be either filename 4257 to save command line and device configuration into file or dash 4258 ``-``) character to print the output to stdout. This can be later 4259 used as input file for ``-readconfig`` option. 4260ERST 4261 4262DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4263 "-no-user-config\n" 4264 " do not load default user-provided config files at startup\n", 4265 QEMU_ARCH_ALL) 4266SRST 4267``-no-user-config`` 4268 The ``-no-user-config`` option makes QEMU not load any of the 4269 user-provided config files on sysconfdir. 4270ERST 4271 4272DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4273 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4274 " specify tracing options\n", 4275 QEMU_ARCH_ALL) 4276SRST 4277``-trace [[enable=]pattern][,events=file][,file=file]`` 4278 .. include:: ../qemu-option-trace.rst.inc 4279 4280ERST 4281DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4282 "-plugin [file=]<file>[,arg=<string>]\n" 4283 " load a plugin\n", 4284 QEMU_ARCH_ALL) 4285SRST 4286``-plugin file=file[,arg=string]`` 4287 Load a plugin. 4288 4289 ``file=file`` 4290 Load the given plugin from a shared library file. 4291 4292 ``arg=string`` 4293 Argument string passed to the plugin. (Can be given multiple 4294 times.) 4295ERST 4296 4297HXCOMM Internal use 4298DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4299DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4300 4301#ifdef __linux__ 4302DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4303 "-enable-fips enable FIPS 140-2 compliance\n", 4304 QEMU_ARCH_ALL) 4305#endif 4306SRST 4307``-enable-fips`` 4308 Enable FIPS 140-2 compliance mode. 4309ERST 4310 4311HXCOMM Deprecated by -accel tcg 4312DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386) 4313 4314DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4315 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4316 " control error message format\n" 4317 " timestamp=on enables timestamps (default: off)\n" 4318 " guest-name=on enables guest name prefix but only if\n" 4319 " -name guest option is set (default: off)\n", 4320 QEMU_ARCH_ALL) 4321SRST 4322``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4323 Control error message format. 4324 4325 ``timestamp=on|off`` 4326 Prefix messages with a timestamp. Default is off. 4327 4328 ``guest-name=on|off`` 4329 Prefix messages with guest name but only if -name guest option is set 4330 otherwise the option is ignored. Default is off. 4331ERST 4332 4333DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4334 "-dump-vmstate <file>\n" 4335 " Output vmstate information in JSON format to file.\n" 4336 " Use the scripts/vmstate-static-checker.py file to\n" 4337 " check for possible regressions in migration code\n" 4338 " by comparing two such vmstate dumps.\n", 4339 QEMU_ARCH_ALL) 4340SRST 4341``-dump-vmstate file`` 4342 Dump json-encoded vmstate information for current machine type to 4343 file in file 4344ERST 4345 4346DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4347 "-enable-sync-profile\n" 4348 " enable synchronization profiling\n", 4349 QEMU_ARCH_ALL) 4350SRST 4351``-enable-sync-profile`` 4352 Enable synchronization profiling. 4353ERST 4354 4355DEFHEADING() 4356 4357DEFHEADING(Generic object creation:) 4358 4359DEF("object", HAS_ARG, QEMU_OPTION_object, 4360 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4361 " create a new object of type TYPENAME setting properties\n" 4362 " in the order they are specified. Note that the 'id'\n" 4363 " property must be set. These objects are placed in the\n" 4364 " '/objects' path.\n", 4365 QEMU_ARCH_ALL) 4366SRST 4367``-object typename[,prop1=value1,...]`` 4368 Create a new object of type typename setting properties in the order 4369 they are specified. Note that the 'id' property must be set. These 4370 objects are placed in the '/objects' path. 4371 4372 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align`` 4373 Creates a memory file backend object, which can be used to back 4374 the guest RAM with huge pages. 4375 4376 The ``id`` parameter is a unique ID that will be used to 4377 reference this memory region when configuring the ``-numa`` 4378 argument. 4379 4380 The ``size`` option provides the size of the memory region, and 4381 accepts common suffixes, eg ``500M``. 4382 4383 The ``mem-path`` provides the path to either a shared memory or 4384 huge page filesystem mount. 4385 4386 The ``share`` boolean option determines whether the memory 4387 region is marked as private to QEMU, or shared. The latter 4388 allows a co-operating external process to access the QEMU memory 4389 region. 4390 4391 The ``share`` is also required for pvrdma devices due to 4392 limitations in the RDMA API provided by Linux. 4393 4394 Setting share=on might affect the ability to configure NUMA 4395 bindings for the memory backend under some circumstances, see 4396 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4397 source tree for additional details. 4398 4399 Setting the ``discard-data`` boolean option to on indicates that 4400 file contents can be destroyed when QEMU exits, to avoid 4401 unnecessarily flushing data to the backing file. Note that 4402 ``discard-data`` is only an optimization, and QEMU might not 4403 discard file contents if it aborts unexpectedly or is terminated 4404 using SIGKILL. 4405 4406 The ``merge`` boolean option enables memory merge, also known as 4407 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4408 the pages for memory deduplication. 4409 4410 Setting the ``dump`` boolean option to off excludes the memory 4411 from core dumps. This feature is also known as MADV\_DONTDUMP. 4412 4413 The ``prealloc`` boolean option enables memory preallocation. 4414 4415 The ``host-nodes`` option binds the memory range to a list of 4416 NUMA host nodes. 4417 4418 The ``policy`` option sets the NUMA policy to one of the 4419 following values: 4420 4421 ``default`` 4422 default host policy 4423 4424 ``preferred`` 4425 prefer the given host node list for allocation 4426 4427 ``bind`` 4428 restrict memory allocation to the given host node list 4429 4430 ``interleave`` 4431 interleave memory allocations across the given host node 4432 list 4433 4434 The ``align`` option specifies the base address alignment when 4435 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4436 ``2M``. Some backend store specified by ``mem-path`` requires an 4437 alignment different than the default one used by QEMU, eg the 4438 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4439 such cases, users can specify the required alignment via this 4440 option. 4441 4442 The ``pmem`` option specifies whether the backing file specified 4443 by ``mem-path`` is in host persistent memory that can be 4444 accessed using the SNIA NVM programming model (e.g. Intel 4445 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4446 operations to guarantee the persistence of its own writes to 4447 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4448 migration). Also, we will map the backend-file with MAP\_SYNC 4449 flag, which ensures the file metadata is in sync for 4450 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4451 requires support from both the host kernel (since Linux kernel 4452 4.15) and the filesystem of ``mem-path`` mounted with DAX 4453 option. 4454 4455 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave`` 4456 Creates a memory backend object, which can be used to back the 4457 guest RAM. Memory backend objects offer more control than the 4458 ``-m`` option that is traditionally used to define guest RAM. 4459 Please refer to ``memory-backend-file`` for a description of the 4460 options. 4461 4462 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size`` 4463 Creates an anonymous memory file backend object, which allows 4464 QEMU to share the memory with an external process (e.g. when 4465 using vhost-user). The memory is allocated with memfd and 4466 optional sealing. (Linux only) 4467 4468 The ``seal`` option creates a sealed-file, that will block 4469 further resizing the memory ('on' by default). 4470 4471 The ``hugetlb`` option specify the file to be created resides in 4472 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4473 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4474 the hugetlb page size on systems that support multiple hugetlb 4475 page sizes (it must be a power of 2 value supported by the 4476 system). 4477 4478 In some versions of Linux, the ``hugetlb`` option is 4479 incompatible with the ``seal`` option (requires at least Linux 4480 4.16). 4481 4482 Please refer to ``memory-backend-file`` for a description of the 4483 other options. 4484 4485 The ``share`` boolean option is on by default with memfd. 4486 4487 ``-object rng-builtin,id=id`` 4488 Creates a random number generator backend which obtains entropy 4489 from QEMU builtin functions. The ``id`` parameter is a unique ID 4490 that will be used to reference this entropy backend from the 4491 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4492 uses this RNG backend. 4493 4494 ``-object rng-random,id=id,filename=/dev/random`` 4495 Creates a random number generator backend which obtains entropy 4496 from a device on the host. The ``id`` parameter is a unique ID 4497 that will be used to reference this entropy backend from the 4498 ``virtio-rng`` device. The ``filename`` parameter specifies 4499 which file to obtain entropy from and if omitted defaults to 4500 ``/dev/urandom``. 4501 4502 ``-object rng-egd,id=id,chardev=chardevid`` 4503 Creates a random number generator backend which obtains entropy 4504 from an external daemon running on the host. The ``id`` 4505 parameter is a unique ID that will be used to reference this 4506 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4507 parameter is the unique ID of a character device backend that 4508 provides the connection to the RNG daemon. 4509 4510 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4511 Creates a TLS anonymous credentials object, which can be used to 4512 provide TLS support on network backends. The ``id`` parameter is 4513 a unique ID which network backends will use to access the 4514 credentials. The ``endpoint`` is either ``server`` or ``client`` 4515 depending on whether the QEMU network backend that uses the 4516 credentials will be acting as a client or as a server. If 4517 ``verify-peer`` is enabled (the default) then once the handshake 4518 is completed, the peer credentials will be verified, though this 4519 is a no-op for anonymous credentials. 4520 4521 The dir parameter tells QEMU where to find the credential files. 4522 For server endpoints, this directory may contain a file 4523 dh-params.pem providing diffie-hellman parameters to use for the 4524 TLS server. If the file is missing, QEMU will generate a set of 4525 DH parameters at startup. This is a computationally expensive 4526 operation that consumes random pool entropy, so it is 4527 recommended that a persistent set of parameters be generated 4528 upfront and saved. 4529 4530 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4531 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4532 can be used to provide TLS support on network backends. The 4533 ``id`` parameter is a unique ID which network backends will use 4534 to access the credentials. The ``endpoint`` is either ``server`` 4535 or ``client`` depending on whether the QEMU network backend that 4536 uses the credentials will be acting as a client or as a server. 4537 For clients only, ``username`` is the username which will be 4538 sent to the server. If omitted it defaults to "qemu". 4539 4540 The dir parameter tells QEMU where to find the keys file. It is 4541 called "dir/keys.psk" and contains "username:key" pairs. This 4542 file can most easily be created using the GnuTLS ``psktool`` 4543 program. 4544 4545 For server endpoints, dir may also contain a file dh-params.pem 4546 providing diffie-hellman parameters to use for the TLS server. 4547 If the file is missing, QEMU will generate a set of DH 4548 parameters at startup. This is a computationally expensive 4549 operation that consumes random pool entropy, so it is 4550 recommended that a persistent set of parameters be generated up 4551 front and saved. 4552 4553 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4554 Creates a TLS anonymous credentials object, which can be used to 4555 provide TLS support on network backends. The ``id`` parameter is 4556 a unique ID which network backends will use to access the 4557 credentials. The ``endpoint`` is either ``server`` or ``client`` 4558 depending on whether the QEMU network backend that uses the 4559 credentials will be acting as a client or as a server. If 4560 ``verify-peer`` is enabled (the default) then once the handshake 4561 is completed, the peer credentials will be verified. With x509 4562 certificates, this implies that the clients must be provided 4563 with valid client certificates too. 4564 4565 The dir parameter tells QEMU where to find the credential files. 4566 For server endpoints, this directory may contain a file 4567 dh-params.pem providing diffie-hellman parameters to use for the 4568 TLS server. If the file is missing, QEMU will generate a set of 4569 DH parameters at startup. This is a computationally expensive 4570 operation that consumes random pool entropy, so it is 4571 recommended that a persistent set of parameters be generated 4572 upfront and saved. 4573 4574 For x509 certificate credentials the directory will contain 4575 further files providing the x509 certificates. The certificates 4576 must be stored in PEM format, in filenames ca-cert.pem, 4577 ca-crl.pem (optional), server-cert.pem (only servers), 4578 server-key.pem (only servers), client-cert.pem (only clients), 4579 and client-key.pem (only clients). 4580 4581 For the server-key.pem and client-key.pem files which contain 4582 sensitive private keys, it is possible to use an encrypted 4583 version by providing the passwordid parameter. This provides the 4584 ID of a previously created ``secret`` object containing the 4585 password for decryption. 4586 4587 The priority parameter allows to override the global default 4588 priority used by gnutls. This can be useful if the system 4589 administrator needs to use a weaker set of crypto priorities for 4590 QEMU without potentially forcing the weakness onto all 4591 applications. Or conversely if one wants wants a stronger 4592 default for QEMU than for all other applications, they can do 4593 this through this parameter. Its format is a gnutls priority 4594 string as described at 4595 https://gnutls.org/manual/html_node/Priority-Strings.html. 4596 4597 ``-object tls-cipher-suites,id=id,priority=priority`` 4598 Creates a TLS cipher suites object, which can be used to control 4599 the TLS cipher/protocol algorithms that applications are permitted 4600 to use. 4601 4602 The ``id`` parameter is a unique ID which frontends will use to 4603 access the ordered list of permitted TLS cipher suites from the 4604 host. 4605 4606 The ``priority`` parameter allows to override the global default 4607 priority used by gnutls. This can be useful if the system 4608 administrator needs to use a weaker set of crypto priorities for 4609 QEMU without potentially forcing the weakness onto all 4610 applications. Or conversely if one wants wants a stronger 4611 default for QEMU than for all other applications, they can do 4612 this through this parameter. Its format is a gnutls priority 4613 string as described at 4614 https://gnutls.org/manual/html_node/Priority-Strings.html. 4615 4616 An example of use of this object is to control UEFI HTTPS Boot. 4617 The tls-cipher-suites object exposes the ordered list of permitted 4618 TLS cipher suites from the host side to the guest firmware, via 4619 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4620 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4621 guest-side TLS. 4622 4623 In the following example, the priority at which the host-side policy 4624 is retrieved is given by the ``priority`` property. 4625 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4626 refer to /etc/crypto-policies/back-ends/gnutls.config. 4627 4628 .. parsed-literal:: 4629 4630 # |qemu_system| \ 4631 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \ 4632 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4633 4634 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4635 Interval t can't be 0, this filter batches the packet delivery: 4636 all packets arriving in a given interval on netdev netdevid are 4637 delayed until the end of the interval. Interval is in 4638 microseconds. ``status`` is optional that indicate whether the 4639 netfilter is on (enabled) or off (disabled), the default status 4640 for netfilter will be 'on'. 4641 4642 queue all\|rx\|tx is an option that can be applied to any 4643 netfilter. 4644 4645 ``all``: the filter is attached both to the receive and the 4646 transmit queue of the netdev (default). 4647 4648 ``rx``: the filter is attached to the receive queue of the 4649 netdev, where it will receive packets sent to the netdev. 4650 4651 ``tx``: the filter is attached to the transmit queue of the 4652 netdev, where it will receive packets sent by the netdev. 4653 4654 position head\|tail\|id=<id> is an option to specify where the 4655 filter should be inserted in the filter list. It can be applied 4656 to any netfilter. 4657 4658 ``head``: the filter is inserted at the head of the filter list, 4659 before any existing filters. 4660 4661 ``tail``: the filter is inserted at the tail of the filter list, 4662 behind any existing filters (default). 4663 4664 ``id=<id>``: the filter is inserted before or behind the filter 4665 specified by <id>, see the insert option below. 4666 4667 insert behind\|before is an option to specify where to insert 4668 the new filter relative to the one specified with 4669 position=id=<id>. It can be applied to any netfilter. 4670 4671 ``before``: insert before the specified filter. 4672 4673 ``behind``: insert behind the specified filter (default). 4674 4675 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4676 filter-mirror on netdev netdevid,mirror net packet to 4677 chardevchardevid, if it has the vnet\_hdr\_support flag, 4678 filter-mirror will mirror packet with vnet\_hdr\_len. 4679 4680 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4681 filter-redirector on netdev netdevid,redirect filter's net 4682 packet to chardev chardevid,and redirect indev's packet to 4683 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4684 will redirect packet with vnet\_hdr\_len. Create a 4685 filter-redirector we need to differ outdev id from indev id, id 4686 can not be the same. we can just use indev or outdev, but at 4687 least one of indev or outdev need to be specified. 4688 4689 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4690 Filter-rewriter is a part of COLO project.It will rewrite tcp 4691 packet to secondary from primary to keep secondary tcp 4692 connection,and rewrite tcp packet to primary from secondary make 4693 tcp packet can be handled by client.if it has the 4694 vnet\_hdr\_support flag, we can parse packet with vnet header. 4695 4696 usage: colo secondary: -object 4697 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4698 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4699 filter-rewriter,id=rew0,netdev=hn0,queue=all 4700 4701 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4702 Dump the network traffic on netdev dev to the file specified by 4703 filename. At most len bytes (64k by default) per packet are 4704 stored. The file format is libpcap, so it can be analyzed with 4705 tools such as tcpdump or Wireshark. 4706 4707 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]`` 4708 Colo-compare gets packet from primary\_in chardevid and 4709 secondary\_in, then compare whether the payload of primary packet 4710 and secondary packet are the same. If same, it will output 4711 primary packet to out\_dev, else it will notify COLO-framework to do 4712 checkpoint and send primary packet to out\_dev. In order to 4713 improve efficiency, we need to put the task of comparison in 4714 another iothread. If it has the vnet\_hdr\_support flag, 4715 colo compare will send/recv packet with vnet\_hdr\_len. 4716 The compare\_timeout=@var{ms} determines the maximum time of the 4717 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4718 is to set the period of scanning expired primary node network packets. 4719 The max\_queue\_size=@var{size} is to set the max compare queue 4720 size depend on user environment. 4721 If user want to use Xen COLO, need to add the notify\_dev to 4722 notify Xen colo-frame to do checkpoint. 4723 4724 COLO-compare must be used with the help of filter-mirror, 4725 filter-redirector and filter-rewriter. 4726 4727 :: 4728 4729 KVM COLO 4730 4731 primary: 4732 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4733 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4734 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4735 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4736 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4737 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4738 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4739 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4740 -object iothread,id=iothread1 4741 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4742 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4743 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4744 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4745 4746 secondary: 4747 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4748 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4749 -chardev socket,id=red0,host=3.3.3.3,port=9003 4750 -chardev socket,id=red1,host=3.3.3.3,port=9004 4751 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4752 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4753 4754 4755 Xen COLO 4756 4757 primary: 4758 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4759 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4760 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4761 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4762 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4763 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4764 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4765 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4766 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait 4767 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4768 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4769 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4770 -object iothread,id=iothread1 4771 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4772 4773 secondary: 4774 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4775 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4776 -chardev socket,id=red0,host=3.3.3.3,port=9003 4777 -chardev socket,id=red1,host=3.3.3.3,port=9004 4778 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4779 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4780 4781 If you want to know the detail of above command line, you can 4782 read the colo-compare git log. 4783 4784 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4785 Creates a cryptodev backend which executes crypto opreation from 4786 the QEMU cipher APIS. The id parameter is a unique ID that will 4787 be used to reference this cryptodev backend from the 4788 ``virtio-crypto`` device. The queues parameter is optional, 4789 which specify the queue number of cryptodev backend, the default 4790 of queues is 1. 4791 4792 .. parsed-literal:: 4793 4794 # |qemu_system| \ 4795 [...] \ 4796 -object cryptodev-backend-builtin,id=cryptodev0 \ 4797 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \ 4798 [...] 4799 4800 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4801 Creates a vhost-user cryptodev backend, backed by a chardev 4802 chardevid. The id parameter is a unique ID that will be used to 4803 reference this cryptodev backend from the ``virtio-crypto`` 4804 device. The chardev should be a unix domain socket backed one. 4805 The vhost-user uses a specifically defined protocol to pass 4806 vhost ioctl replacement messages to an application on the other 4807 end of the socket. The queues parameter is optional, which 4808 specify the queue number of cryptodev backend for multiqueue 4809 vhost-user, the default of queues is 1. 4810 4811 .. parsed-literal:: 4812 4813 # |qemu_system| \ 4814 [...] \ 4815 -chardev socket,id=chardev0,path=/path/to/socket \ 4816 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \ 4817 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \ 4818 [...] 4819 4820 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 4821 \ 4822 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 4823 Defines a secret to store a password, encryption key, or some 4824 other sensitive data. The sensitive data can either be passed 4825 directly via the data parameter, or indirectly via the file 4826 parameter. Using the data parameter is insecure unless the 4827 sensitive data is encrypted. 4828 4829 The sensitive data can be provided in raw format (the default), 4830 or base64. When encoded as JSON, the raw format only supports 4831 valid UTF-8 characters, so base64 is recommended for sending 4832 binary data. QEMU will convert from which ever format is 4833 provided to the format it needs internally. eg, an RBD password 4834 can be provided in raw format, even though it will be base64 4835 encoded when passed onto the RBD sever. 4836 4837 For added protection, it is possible to encrypt the data 4838 associated with a secret using the AES-256-CBC cipher. Use of 4839 encryption is indicated by providing the keyid and iv 4840 parameters. The keyid parameter provides the ID of a previously 4841 defined secret that contains the AES-256 decryption key. This 4842 key should be 32-bytes long and be base64 encoded. The iv 4843 parameter provides the random initialization vector used for 4844 encryption of this particular secret and should be a base64 4845 encrypted string of the 16-byte IV. 4846 4847 The simplest (insecure) usage is to provide the secret inline 4848 4849 .. parsed-literal:: 4850 4851 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 4852 4853 The simplest secure usage is to provide the secret via a file 4854 4855 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 4856 secret,id=sec0,file=mypasswd.txt,format=raw 4857 4858 For greater security, AES-256-CBC should be used. To illustrate 4859 usage, consider the openssl command line tool which can encrypt 4860 the data. Note that when encrypting, the plaintext must be 4861 padded to the cipher block size (32 bytes) using the standard 4862 PKCS#5/6 compatible padding algorithm. 4863 4864 First a master key needs to be created in base64 encoding: 4865 4866 :: 4867 4868 # openssl rand -base64 32 > key.b64 4869 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4870 4871 Each secret to be encrypted needs to have a random 4872 initialization vector generated. These do not need to be kept 4873 secret 4874 4875 :: 4876 4877 # openssl rand -base64 16 > iv.b64 4878 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4879 4880 The secret to be defined can now be encrypted, in this case 4881 we're telling openssl to base64 encode the result, but it could 4882 be left as raw bytes if desired. 4883 4884 :: 4885 4886 # SECRET=$(printf "letmein" | 4887 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4888 4889 When launching QEMU, create a master secret pointing to 4890 ``key.b64`` and specify that to be used to decrypt the user 4891 password. Pass the contents of ``iv.b64`` to the second secret 4892 4893 .. parsed-literal:: 4894 4895 # |qemu_system| \ 4896 -object secret,id=secmaster0,format=base64,file=key.b64 \ 4897 -object secret,id=sec0,keyid=secmaster0,format=base64,\ 4898 data=$SECRET,iv=$(<iv.b64) 4899 4900 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file]`` 4901 Create a Secure Encrypted Virtualization (SEV) guest object, 4902 which can be used to provide the guest memory encryption support 4903 on AMD processors. 4904 4905 When memory encryption is enabled, one of the physical address 4906 bit (aka the C-bit) is utilized to mark if a memory page is 4907 protected. The ``cbitpos`` is used to provide the C-bit 4908 position. The C-bit position is Host family dependent hence user 4909 must provide this value. On EPYC, the value should be 47. 4910 4911 When memory encryption is enabled, we loose certain bits in 4912 physical address space. The ``reduced-phys-bits`` is used to 4913 provide the number of bits we loose in physical address space. 4914 Similar to C-bit, the value is Host family dependent. On EPYC, 4915 the value should be 5. 4916 4917 The ``sev-device`` provides the device file to use for 4918 communicating with the SEV firmware running inside AMD Secure 4919 Processor. The default device is '/dev/sev'. If hardware 4920 supports memory encryption then /dev/sev devices are created by 4921 CCP driver. 4922 4923 The ``policy`` provides the guest policy to be enforced by the 4924 SEV firmware and restrict what configuration and operational 4925 commands can be performed on this guest by the hypervisor. The 4926 policy should be provided by the guest owner and is bound to the 4927 guest and cannot be changed throughout the lifetime of the 4928 guest. The default is 0. 4929 4930 If guest ``policy`` allows sharing the key with another SEV 4931 guest then ``handle`` can be use to provide handle of the guest 4932 from which to share the key. 4933 4934 The ``dh-cert-file`` and ``session-file`` provides the guest 4935 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 4936 and session parameters are used for establishing a cryptographic 4937 session with the guest owner to negotiate keys used for 4938 attestation. The file must be encoded in base64. 4939 4940 e.g to launch a SEV guest 4941 4942 .. parsed-literal:: 4943 4944 # |qemu_system_x86| \ 4945 ...... 4946 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \ 4947 -machine ...,memory-encryption=sev0 4948 ..... 4949 4950 ``-object authz-simple,id=id,identity=string`` 4951 Create an authorization object that will control access to 4952 network services. 4953 4954 The ``identity`` parameter is identifies the user and its format 4955 depends on the network service that authorization object is 4956 associated with. For authorizing based on TLS x509 certificates, 4957 the identity must be the x509 distinguished name. Note that care 4958 must be taken to escape any commas in the distinguished name. 4959 4960 An example authorization object to validate a x509 distinguished 4961 name would look like: 4962 4963 .. parsed-literal:: 4964 4965 # |qemu_system| \ 4966 ... 4967 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \ 4968 ... 4969 4970 Note the use of quotes due to the x509 distinguished name 4971 containing whitespace, and escaping of ','. 4972 4973 ``-object authz-listfile,id=id,filename=path,refresh=yes|no`` 4974 Create an authorization object that will control access to 4975 network services. 4976 4977 The ``filename`` parameter is the fully qualified path to a file 4978 containing the access control list rules in JSON format. 4979 4980 An example set of rules that match against SASL usernames might 4981 look like: 4982 4983 :: 4984 4985 { 4986 "rules": [ 4987 { "match": "fred", "policy": "allow", "format": "exact" }, 4988 { "match": "bob", "policy": "allow", "format": "exact" }, 4989 { "match": "danb", "policy": "deny", "format": "glob" }, 4990 { "match": "dan*", "policy": "allow", "format": "exact" }, 4991 ], 4992 "policy": "deny" 4993 } 4994 4995 When checking access the object will iterate over all the rules 4996 and the first rule to match will have its ``policy`` value 4997 returned as the result. If no rules match, then the default 4998 ``policy`` value is returned. 4999 5000 The rules can either be an exact string match, or they can use 5001 the simple UNIX glob pattern matching to allow wildcards to be 5002 used. 5003 5004 If ``refresh`` is set to true the file will be monitored and 5005 automatically reloaded whenever its content changes. 5006 5007 As with the ``authz-simple`` object, the format of the identity 5008 strings being matched depends on the network service, but is 5009 usually a TLS x509 distinguished name, or a SASL username. 5010 5011 An example authorization object to validate a SASL username 5012 would look like: 5013 5014 .. parsed-literal:: 5015 5016 # |qemu_system| \ 5017 ... 5018 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=yes 5019 ... 5020 5021 ``-object authz-pam,id=id,service=string`` 5022 Create an authorization object that will control access to 5023 network services. 5024 5025 The ``service`` parameter provides the name of a PAM service to 5026 use for authorization. It requires that a file 5027 ``/etc/pam.d/service`` exist to provide the configuration for 5028 the ``account`` subsystem. 5029 5030 An example authorization object to validate a TLS x509 5031 distinguished name would look like: 5032 5033 .. parsed-literal:: 5034 5035 # |qemu_system| \ 5036 ... 5037 -object authz-pam,id=auth0,service=qemu-vnc 5038 ... 5039 5040 There would then be a corresponding config file for PAM at 5041 ``/etc/pam.d/qemu-vnc`` that contains: 5042 5043 :: 5044 5045 account requisite pam_listfile.so item=user sense=allow \ 5046 file=/etc/qemu/vnc.allow 5047 5048 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5049 of x509 distingished names that are permitted access 5050 5051 :: 5052 5053 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5054 5055 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5056 Creates a dedicated event loop thread that devices can be 5057 assigned to. This is known as an IOThread. By default device 5058 emulation happens in vCPU threads or the main event loop thread. 5059 This can become a scalability bottleneck. IOThreads allow device 5060 emulation and I/O to run on other host CPUs. 5061 5062 The ``id`` parameter is a unique ID that will be used to 5063 reference this IOThread from ``-device ...,iothread=id``. 5064 Multiple devices can be assigned to an IOThread. Note that not 5065 all devices support an ``iothread`` parameter. 5066 5067 The ``query-iothreads`` QMP command lists IOThreads and reports 5068 their thread IDs so that the user can configure host CPU 5069 pinning/affinity. 5070 5071 IOThreads use an adaptive polling algorithm to reduce event loop 5072 latency. Instead of entering a blocking system call to monitor 5073 file descriptors and then pay the cost of being woken up when an 5074 event occurs, the polling algorithm spins waiting for events for 5075 a short time. The algorithm's default parameters are suitable 5076 for many cases but can be adjusted based on knowledge of the 5077 workload and/or host device latency. 5078 5079 The ``poll-max-ns`` parameter is the maximum number of 5080 nanoseconds to busy wait for events. Polling can be disabled by 5081 setting this value to 0. 5082 5083 The ``poll-grow`` parameter is the multiplier used to increase 5084 the polling time when the algorithm detects it is missing events 5085 due to not polling long enough. 5086 5087 The ``poll-shrink`` parameter is the divisor used to decrease 5088 the polling time when the algorithm detects it is spending too 5089 long polling without encountering events. 5090 5091 The polling parameters can be modified at run-time using the 5092 ``qom-set`` command (where ``iothread1`` is the IOThread's 5093 ``id``): 5094 5095 :: 5096 5097 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5098ERST 5099 5100 5101HXCOMM This is the last statement. Insert new options before this line! 5102
