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 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\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 ``memory-encryption=`` 95 Memory encryption object to use. The default is none. 96 97 ``hmat=on|off`` 98 Enables or disables ACPI Heterogeneous Memory Attribute Table 99 (HMAT) support. The default is off. 100 101 ``memory-backend='id'`` 102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 103 Allows to use a memory backend as main RAM. 104 105 For example: 106 :: 107 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 108 -machine memory-backend=pc.ram 109 -m 512M 110 111 Migration compatibility note: 112 a) as backend id one shall use value of 'default-ram-id', advertised by 113 machine type (available via ``query-machines`` QMP command), if migration 114 to/from old QEMU (<5.0) is expected. 115 b) for machine types 4.0 and older, user shall 116 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 117 if migration to/from old QEMU (<5.0) is expected. 118 For example: 119 :: 120 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 121 -machine memory-backend=pc.ram 122 -m 512M 123ERST 124 125HXCOMM Deprecated by -machine 126DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 127 128DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 129 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 130SRST 131``-cpu model`` 132 Select CPU model (``-cpu help`` for list and additional feature 133 selection) 134ERST 135 136DEF("accel", HAS_ARG, QEMU_OPTION_accel, 137 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 138 " select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n" 139 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 140 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 141 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 142 " split-wx=on|off (enable TCG split w^x mapping)\n" 143 " tb-size=n (TCG translation block cache size)\n" 144 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 145SRST 146``-accel name[,prop=value[,...]]`` 147 This is used to enable an accelerator. Depending on the target 148 architecture, kvm, xen, hax, hvf, whpx or tcg can be available. By 149 default, tcg is used. If there is more than one accelerator 150 specified, the next one is used if the previous one fails to 151 initialize. 152 153 ``igd-passthru=on|off`` 154 When Xen is in use, this option controls whether Intel 155 integrated graphics devices can be passed through to the guest 156 (default=off) 157 158 ``kernel-irqchip=on|off|split`` 159 Controls KVM in-kernel irqchip support. The default is full 160 acceleration of the interrupt controllers. On x86, split irqchip 161 reduces the kernel attack surface, at a performance cost for 162 non-MSI interrupts. Disabling the in-kernel irqchip completely 163 is not recommended except for debugging purposes. 164 165 ``kvm-shadow-mem=size`` 166 Defines the size of the KVM shadow MMU. 167 168 ``split-wx=on|off`` 169 Controls the use of split w^x mapping for the TCG code generation 170 buffer. Some operating systems require this to be enabled, and in 171 such a case this will default on. On other operating systems, this 172 will default off, but one may enable this for testing or debugging. 173 174 ``tb-size=n`` 175 Controls the size (in MiB) of the TCG translation block cache. 176 177 ``thread=single|multi`` 178 Controls number of TCG threads. When the TCG is multi-threaded 179 there will be one thread per vCPU therefore taking advantage of 180 additional host cores. The default is to enable multi-threading 181 where both the back-end and front-ends support it and no 182 incompatible TCG features have been enabled (e.g. 183 icount/replay). 184ERST 185 186DEF("smp", HAS_ARG, QEMU_OPTION_smp, 187 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 188 " set the number of CPUs to 'n' [default=1]\n" 189 " maxcpus= maximum number of total cpus, including\n" 190 " offline CPUs for hotplug, etc\n" 191 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 192 " threads= number of threads on one CPU core\n" 193 " dies= number of CPU dies on one socket (for PC only)\n" 194 " sockets= number of discrete sockets in the system\n", 195 QEMU_ARCH_ALL) 196SRST 197``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 198 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 199 are supported. On Sparc32 target, Linux limits the number of usable 200 CPUs to 4. For the PC target, the number of cores per die, the 201 number of threads per cores, the number of dies per packages and the 202 total number of sockets can be specified. Missing values will be 203 computed. If any on the three values is given, the total number of 204 CPUs n can be omitted. maxcpus specifies the maximum number of 205 hotpluggable CPUs. 206ERST 207 208DEF("numa", HAS_ARG, QEMU_OPTION_numa, 209 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 210 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 211 "-numa dist,src=source,dst=destination,val=distance\n" 212 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 213 "-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" 214 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 215 QEMU_ARCH_ALL) 216SRST 217``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 218 \ 219``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 220 \ 221``-numa dist,src=source,dst=destination,val=distance`` 222 \ 223``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 224 \ 225``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 226 \ 227``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 228 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 229 distance from a source node to a destination node. Set the ACPI 230 Heterogeneous Memory Attributes for the given nodes. 231 232 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 233 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 234 contiguous range of CPU indexes (or a single VCPU if lastcpu is 235 omitted). A non-contiguous set of VCPUs can be represented by 236 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 237 omitted on all nodes, VCPUs are automatically split between them. 238 239 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 240 NUMA node: 241 242 :: 243 244 -numa node,cpus=0-2,cpus=5 245 246 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 247 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 248 assign CPU objects to a node using topology layout properties of 249 CPU. The set of properties is machine specific, and depends on used 250 machine type/'\ ``smp``\ ' options. It could be queried with 251 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 252 property specifies node to which CPU object will be assigned, it's 253 required for node to be declared with '\ ``node``\ ' option before 254 it's used with '\ ``cpu``\ ' option. 255 256 For example: 257 258 :: 259 260 -M pc \ 261 -smp 1,sockets=2,maxcpus=2 \ 262 -numa node,nodeid=0 -numa node,nodeid=1 \ 263 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 264 265 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 266 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 267 a given memory backend device to a node. If '\ ``mem``\ ' and 268 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 269 270 271 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 272 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 273 use it. 274 275 '\ ``initiator``\ ' is an additional option that points to an 276 initiator NUMA node that has best performance (the lowest latency or 277 largest bandwidth) to this NUMA node. Note that this option can be 278 set only when the machine property 'hmat' is set to 'on'. 279 280 Following example creates a machine with 2 NUMA nodes, node 0 has 281 CPU. node 1 has only memory, and its initiator is node 0. Note that 282 because node 0 has CPU, by default the initiator of node 0 is itself 283 and must be itself. 284 285 :: 286 287 -machine hmat=on \ 288 -m 2G,slots=2,maxmem=4G \ 289 -object memory-backend-ram,size=1G,id=m0 \ 290 -object memory-backend-ram,size=1G,id=m1 \ 291 -numa node,nodeid=0,memdev=m0 \ 292 -numa node,nodeid=1,memdev=m1,initiator=0 \ 293 -smp 2,sockets=2,maxcpus=2 \ 294 -numa cpu,node-id=0,socket-id=0 \ 295 -numa cpu,node-id=0,socket-id=1 296 297 source and destination are NUMA node IDs. distance is the NUMA 298 distance from source to destination. The distance from a node to 299 itself is always 10. If any pair of nodes is given a distance, then 300 all pairs must be given distances. Although, when distances are only 301 given in one direction for each pair of nodes, then the distances in 302 the opposite directions are assumed to be the same. If, however, an 303 asymmetrical pair of distances is given for even one node pair, then 304 all node pairs must be provided distance values for both directions, 305 even when they are symmetrical. When a node is unreachable from 306 another node, set the pair's distance to 255. 307 308 Note that the -``numa`` option doesn't allocate any of the specified 309 resources, it just assigns existing resources to NUMA nodes. This 310 means that one still has to use the ``-m``, ``-smp`` options to 311 allocate RAM and VCPUs respectively. 312 313 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 314 Information between initiator and target NUMA nodes in ACPI 315 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 316 create memory requests, usually it has one or more processors. 317 Target NUMA node contains addressable memory. 318 319 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 320 the memory hierarchy of the target NUMA node: if hierarchy is 321 'memory', the structure represents the memory performance; if 322 hierarchy is 'first-level\|second-level\|third-level', this 323 structure represents aggregated performance of memory side caches 324 for each domain. type of 'data-type' is type of data represented by 325 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 326 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 327 the target memory; if 'hierarchy' is 328 'first-level\|second-level\|third-level', 'data-type' is 329 'access\|read\|write' hit latency or 'access\|read\|write' hit 330 bandwidth of the target memory side cache. 331 332 lat is latency value in nanoseconds. bw is bandwidth value, the 333 possible value and units are NUM[M\|G\|T], mean that the bandwidth 334 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 335 used suffix). Note that if latency or bandwidth value is 0, means 336 the corresponding latency or bandwidth information is not provided. 337 338 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 339 belongs. size is the size of memory side cache in bytes. level is 340 the cache level described in this structure, note that the cache 341 level 0 should not be used with '\ ``hmat-cache``\ ' option. 342 associativity is the cache associativity, the possible value is 343 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 344 is the write policy. line is the cache Line size in bytes. 345 346 For example, the following options describe 2 NUMA nodes. Node 0 has 347 2 cpus and a ram, node 1 has only a ram. The processors in node 0 348 access memory in node 0 with access-latency 5 nanoseconds, 349 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 350 memory in NUMA node 1 with access-latency 10 nanoseconds, 351 access-bandwidth is 100 MB/s. And for memory side cache information, 352 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 353 policy is write-back, the cache Line size is 8 bytes: 354 355 :: 356 357 -machine hmat=on \ 358 -m 2G \ 359 -object memory-backend-ram,size=1G,id=m0 \ 360 -object memory-backend-ram,size=1G,id=m1 \ 361 -smp 2 \ 362 -numa node,nodeid=0,memdev=m0 \ 363 -numa node,nodeid=1,memdev=m1,initiator=0 \ 364 -numa cpu,node-id=0,socket-id=0 \ 365 -numa cpu,node-id=0,socket-id=1 \ 366 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 367 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 368 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 369 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 370 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 371 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 372ERST 373 374DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 375 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 376 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 377SRST 378``-add-fd fd=fd,set=set[,opaque=opaque]`` 379 Add a file descriptor to an fd set. Valid options are: 380 381 ``fd=fd`` 382 This option defines the file descriptor of which a duplicate is 383 added to fd set. The file descriptor cannot be stdin, stdout, or 384 stderr. 385 386 ``set=set`` 387 This option defines the ID of the fd set to add the file 388 descriptor to. 389 390 ``opaque=opaque`` 391 This option defines a free-form string that can be used to 392 describe fd. 393 394 You can open an image using pre-opened file descriptors from an fd 395 set: 396 397 .. parsed-literal:: 398 399 |qemu_system| \\ 400 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 401 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 402 -drive file=/dev/fdset/2,index=0,media=disk 403ERST 404 405DEF("set", HAS_ARG, QEMU_OPTION_set, 406 "-set group.id.arg=value\n" 407 " set <arg> parameter for item <id> of type <group>\n" 408 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 409SRST 410``-set group.id.arg=value`` 411 Set parameter arg for item id of type group 412ERST 413 414DEF("global", HAS_ARG, QEMU_OPTION_global, 415 "-global driver.property=value\n" 416 "-global driver=driver,property=property,value=value\n" 417 " set a global default for a driver property\n", 418 QEMU_ARCH_ALL) 419SRST 420``-global driver.prop=value`` 421 \ 422``-global driver=driver,property=property,value=value`` 423 Set default value of driver's property prop to value, e.g.: 424 425 .. parsed-literal:: 426 427 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 428 429 In particular, you can use this to set driver properties for devices 430 which are created automatically by the machine model. To create a 431 device which is not created automatically and set properties on it, 432 use -``device``. 433 434 -global driver.prop=value is shorthand for -global 435 driver=driver,property=prop,value=value. The longhand syntax works 436 even when driver contains a dot. 437ERST 438 439DEF("boot", HAS_ARG, QEMU_OPTION_boot, 440 "-boot [order=drives][,once=drives][,menu=on|off]\n" 441 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 442 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 443 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 444 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 445 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 446 QEMU_ARCH_ALL) 447SRST 448``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 449 Specify boot order drives as a string of drive letters. Valid drive 450 letters depend on the target architecture. The x86 PC uses: a, b 451 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 452 (Etherboot from network adapter 1-4), hard disk boot is the default. 453 To apply a particular boot order only on the first startup, specify 454 it via ``once``. Note that the ``order`` or ``once`` parameter 455 should not be used together with the ``bootindex`` property of 456 devices, since the firmware implementations normally do not support 457 both at the same time. 458 459 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 460 as firmware/BIOS supports them. The default is non-interactive boot. 461 462 A splash picture could be passed to bios, enabling user to show it 463 as logo, when option splash=sp\_name is given and menu=on, If 464 firmware/BIOS supports them. Currently Seabios for X86 system 465 support it. limitation: The splash file could be a jpeg file or a 466 BMP file in 24 BPP format(true color). The resolution should be 467 supported by the SVGA mode, so the recommended is 320x240, 640x480, 468 800x640. 469 470 A timeout could be passed to bios, guest will pause for rb\_timeout 471 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 472 not reboot, qemu passes '-1' to bios by default. Currently Seabios 473 for X86 system support it. 474 475 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 476 it. This only effects when boot priority is changed by bootindex 477 options. The default is non-strict boot. 478 479 .. parsed-literal:: 480 481 # try to boot from network first, then from hard disk 482 |qemu_system_x86| -boot order=nc 483 # boot from CD-ROM first, switch back to default order after reboot 484 |qemu_system_x86| -boot once=d 485 # boot with a splash picture for 5 seconds. 486 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 487 488 Note: The legacy format '-boot drives' is still supported but its 489 use is discouraged as it may be removed from future versions. 490ERST 491 492DEF("m", HAS_ARG, QEMU_OPTION_m, 493 "-m [size=]megs[,slots=n,maxmem=size]\n" 494 " configure guest RAM\n" 495 " size: initial amount of guest memory\n" 496 " slots: number of hotplug slots (default: none)\n" 497 " maxmem: maximum amount of guest memory (default: none)\n" 498 "NOTE: Some architectures might enforce a specific granularity\n", 499 QEMU_ARCH_ALL) 500SRST 501``-m [size=]megs[,slots=n,maxmem=size]`` 502 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 503 Optionally, a suffix of "M" or "G" can be used to signify a value in 504 megabytes or gigabytes respectively. Optional pair slots, maxmem 505 could be used to set amount of hotpluggable memory slots and maximum 506 amount of memory. Note that maxmem must be aligned to the page size. 507 508 For example, the following command-line sets the guest startup RAM 509 size to 1GB, creates 3 slots to hotplug additional memory and sets 510 the maximum memory the guest can reach to 4GB: 511 512 .. parsed-literal:: 513 514 |qemu_system| -m 1G,slots=3,maxmem=4G 515 516 If slots and maxmem are not specified, memory hotplug won't be 517 enabled and the guest startup RAM will never increase. 518ERST 519 520DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 521 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 522SRST 523``-mem-path path`` 524 Allocate guest RAM from a temporarily created file in path. 525ERST 526 527DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 528 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 529 QEMU_ARCH_ALL) 530SRST 531``-mem-prealloc`` 532 Preallocate memory when using -mem-path. 533ERST 534 535DEF("k", HAS_ARG, QEMU_OPTION_k, 536 "-k language use keyboard layout (for example 'fr' for French)\n", 537 QEMU_ARCH_ALL) 538SRST 539``-k language`` 540 Use keyboard layout language (for example ``fr`` for French). This 541 option is only needed where it is not easy to get raw PC keycodes 542 (e.g. on Macs, with some X11 servers or with a VNC or curses 543 display). You don't normally need to use it on PC/Linux or 544 PC/Windows hosts. 545 546 The available layouts are: 547 548 :: 549 550 ar de-ch es fo fr-ca hu ja mk no pt-br sv 551 da en-gb et fr fr-ch is lt nl pl ru th 552 de en-us fi fr-be hr it lv nl-be pt sl tr 553 554 The default is ``en-us``. 555ERST 556 557 558HXCOMM Deprecated by -audiodev 559DEF("audio-help", 0, QEMU_OPTION_audio_help, 560 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 561 QEMU_ARCH_ALL) 562SRST 563``-audio-help`` 564 Will show the -audiodev equivalent of the currently specified 565 (deprecated) environment variables. 566ERST 567 568DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 569 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 570 " specifies the audio backend to use\n" 571 " id= identifier of the backend\n" 572 " timer-period= timer period in microseconds\n" 573 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 574 " in|out.fixed-settings= use fixed settings for host audio\n" 575 " in|out.frequency= frequency to use with fixed settings\n" 576 " in|out.channels= number of channels to use with fixed settings\n" 577 " in|out.format= sample format to use with fixed settings\n" 578 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 579 " in|out.voices= number of voices to use\n" 580 " in|out.buffer-length= length of buffer in microseconds\n" 581 "-audiodev none,id=id,[,prop[=value][,...]]\n" 582 " dummy driver that discards all output\n" 583#ifdef CONFIG_AUDIO_ALSA 584 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 585 " in|out.dev= name of the audio device to use\n" 586 " in|out.period-length= length of period in microseconds\n" 587 " in|out.try-poll= attempt to use poll mode\n" 588 " threshold= threshold (in microseconds) when playback starts\n" 589#endif 590#ifdef CONFIG_AUDIO_COREAUDIO 591 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 592 " in|out.buffer-count= number of buffers\n" 593#endif 594#ifdef CONFIG_AUDIO_DSOUND 595 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 596 " latency= add extra latency to playback in microseconds\n" 597#endif 598#ifdef CONFIG_AUDIO_OSS 599 "-audiodev oss,id=id[,prop[=value][,...]]\n" 600 " in|out.dev= path of the audio device to use\n" 601 " in|out.buffer-count= number of buffers\n" 602 " in|out.try-poll= attempt to use poll mode\n" 603 " try-mmap= try using memory mapped access\n" 604 " exclusive= open device in exclusive mode\n" 605 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 606#endif 607#ifdef CONFIG_AUDIO_PA 608 "-audiodev pa,id=id[,prop[=value][,...]]\n" 609 " server= PulseAudio server address\n" 610 " in|out.name= source/sink device name\n" 611 " in|out.latency= desired latency in microseconds\n" 612#endif 613#ifdef CONFIG_AUDIO_SDL 614 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 615 " in|out.buffer-count= number of buffers\n" 616#endif 617#ifdef CONFIG_SPICE 618 "-audiodev spice,id=id[,prop[=value][,...]]\n" 619#endif 620 "-audiodev wav,id=id[,prop[=value][,...]]\n" 621 " path= path of wav file to record\n", 622 QEMU_ARCH_ALL) 623SRST 624``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 625 Adds a new audio backend driver identified by id. There are global 626 and driver specific properties. Some values can be set differently 627 for input and output, they're marked with ``in|out.``. You can set 628 the input's property with ``in.prop`` and the output's property with 629 ``out.prop``. For example: 630 631 :: 632 633 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 634 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 635 636 NOTE: parameter validation is known to be incomplete, in many cases 637 specifying an invalid option causes QEMU to print an error message 638 and continue emulation without sound. 639 640 Valid global options are: 641 642 ``id=identifier`` 643 Identifies the audio backend. 644 645 ``timer-period=period`` 646 Sets the timer period used by the audio subsystem in 647 microseconds. Default is 10000 (10 ms). 648 649 ``in|out.mixing-engine=on|off`` 650 Use QEMU's mixing engine to mix all streams inside QEMU and 651 convert audio formats when not supported by the backend. When 652 off, fixed-settings must be off too. Note that disabling this 653 option means that the selected backend must support multiple 654 streams and the audio formats used by the virtual cards, 655 otherwise you'll get no sound. It's not recommended to disable 656 this option unless you want to use 5.1 or 7.1 audio, as mixing 657 engine only supports mono and stereo audio. Default is on. 658 659 ``in|out.fixed-settings=on|off`` 660 Use fixed settings for host audio. When off, it will change 661 based on how the guest opens the sound card. In this case you 662 must not specify frequency, channels or format. Default is on. 663 664 ``in|out.frequency=frequency`` 665 Specify the frequency to use when using fixed-settings. Default 666 is 44100Hz. 667 668 ``in|out.channels=channels`` 669 Specify the number of channels to use when using fixed-settings. 670 Default is 2 (stereo). 671 672 ``in|out.format=format`` 673 Specify the sample format to use when using fixed-settings. 674 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 675 ``u32``, ``f32``. Default is ``s16``. 676 677 ``in|out.voices=voices`` 678 Specify the number of voices to use. Default is 1. 679 680 ``in|out.buffer-length=usecs`` 681 Sets the size of the buffer in microseconds. 682 683``-audiodev none,id=id[,prop[=value][,...]]`` 684 Creates a dummy backend that discards all outputs. This backend has 685 no backend specific properties. 686 687``-audiodev alsa,id=id[,prop[=value][,...]]`` 688 Creates backend using the ALSA. This backend is only available on 689 Linux. 690 691 ALSA specific options are: 692 693 ``in|out.dev=device`` 694 Specify the ALSA device to use for input and/or output. Default 695 is ``default``. 696 697 ``in|out.period-length=usecs`` 698 Sets the period length in microseconds. 699 700 ``in|out.try-poll=on|off`` 701 Attempt to use poll mode with the device. Default is on. 702 703 ``threshold=threshold`` 704 Threshold (in microseconds) when playback starts. Default is 0. 705 706``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 707 Creates a backend using Apple's Core Audio. This backend is only 708 available on Mac OS and only supports playback. 709 710 Core Audio specific options are: 711 712 ``in|out.buffer-count=count`` 713 Sets the count of the buffers. 714 715``-audiodev dsound,id=id[,prop[=value][,...]]`` 716 Creates a backend using Microsoft's DirectSound. This backend is 717 only available on Windows and only supports playback. 718 719 DirectSound specific options are: 720 721 ``latency=usecs`` 722 Add extra usecs microseconds latency to playback. Default is 723 10000 (10 ms). 724 725``-audiodev oss,id=id[,prop[=value][,...]]`` 726 Creates a backend using OSS. This backend is available on most 727 Unix-like systems. 728 729 OSS specific options are: 730 731 ``in|out.dev=device`` 732 Specify the file name of the OSS device to use. Default is 733 ``/dev/dsp``. 734 735 ``in|out.buffer-count=count`` 736 Sets the count of the buffers. 737 738 ``in|out.try-poll=on|of`` 739 Attempt to use poll mode with the device. Default is on. 740 741 ``try-mmap=on|off`` 742 Try using memory mapped device access. Default is off. 743 744 ``exclusive=on|off`` 745 Open the device in exclusive mode (vmix won't work in this 746 case). Default is off. 747 748 ``dsp-policy=policy`` 749 Sets the timing policy (between 0 and 10, where smaller number 750 means smaller latency but higher CPU usage). Use -1 to use 751 buffer sizes specified by ``buffer`` and ``buffer-count``. This 752 option is ignored if you do not have OSS 4. Default is 5. 753 754``-audiodev pa,id=id[,prop[=value][,...]]`` 755 Creates a backend using PulseAudio. This backend is available on 756 most systems. 757 758 PulseAudio specific options are: 759 760 ``server=server`` 761 Sets the PulseAudio server to connect to. 762 763 ``in|out.name=sink`` 764 Use the specified source/sink for recording/playback. 765 766 ``in|out.latency=usecs`` 767 Desired latency in microseconds. The PulseAudio server will try 768 to honor this value but actual latencies may be lower or higher. 769 770``-audiodev sdl,id=id[,prop[=value][,...]]`` 771 Creates a backend using SDL. This backend is available on most 772 systems, but you should use your platform's native backend if 773 possible. 774 775 SDL specific options are: 776 777 ``in|out.buffer-count=count`` 778 Sets the count of the buffers. 779 780``-audiodev spice,id=id[,prop[=value][,...]]`` 781 Creates a backend that sends audio through SPICE. This backend 782 requires ``-spice`` and automatically selected in that case, so 783 usually you can ignore this option. This backend has no backend 784 specific properties. 785 786``-audiodev wav,id=id[,prop[=value][,...]]`` 787 Creates a backend that writes audio to a WAV file. 788 789 Backend specific options are: 790 791 ``path=path`` 792 Write recorded audio into the specified file. Default is 793 ``qemu.wav``. 794ERST 795 796DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 797 "-soundhw c1,... enable audio support\n" 798 " and only specified sound cards (comma separated list)\n" 799 " use '-soundhw help' to get the list of supported cards\n" 800 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 801SRST 802``-soundhw card1[,card2,...] or -soundhw all`` 803 Enable audio and selected sound hardware. Use 'help' to print all 804 available sound hardware. For example: 805 806 .. parsed-literal:: 807 808 |qemu_system_x86| -soundhw sb16,adlib disk.img 809 |qemu_system_x86| -soundhw es1370 disk.img 810 |qemu_system_x86| -soundhw ac97 disk.img 811 |qemu_system_x86| -soundhw hda disk.img 812 |qemu_system_x86| -soundhw all disk.img 813 |qemu_system_x86| -soundhw help 814 815 Note that Linux's i810\_audio OSS kernel (for AC97) module might 816 require manually specifying clocking. 817 818 :: 819 820 modprobe i810_audio clocking=48000 821ERST 822 823DEF("device", HAS_ARG, QEMU_OPTION_device, 824 "-device driver[,prop[=value][,...]]\n" 825 " add device (based on driver)\n" 826 " prop=value,... sets driver properties\n" 827 " use '-device help' to print all possible drivers\n" 828 " use '-device driver,help' to print all possible properties\n", 829 QEMU_ARCH_ALL) 830SRST 831``-device driver[,prop[=value][,...]]`` 832 Add device driver. prop=value sets driver properties. Valid 833 properties depend on the driver. To get help on possible drivers and 834 properties, use ``-device help`` and ``-device driver,help``. 835 836 Some drivers are: 837 838``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 839 Add an IPMI BMC. This is a simulation of a hardware management 840 interface processor that normally sits on a system. It provides a 841 watchdog and the ability to reset and power control the system. You 842 need to connect this to an IPMI interface to make it useful 843 844 The IPMI slave address to use for the BMC. The default is 0x20. This 845 address is the BMC's address on the I2C network of management 846 controllers. If you don't know what this means, it is safe to ignore 847 it. 848 849 ``id=id`` 850 The BMC id for interfaces to use this device. 851 852 ``slave_addr=val`` 853 Define slave address to use for the BMC. The default is 0x20. 854 855 ``sdrfile=file`` 856 file containing raw Sensor Data Records (SDR) data. The default 857 is none. 858 859 ``fruareasize=val`` 860 size of a Field Replaceable Unit (FRU) area. The default is 861 1024. 862 863 ``frudatafile=file`` 864 file containing raw Field Replaceable Unit (FRU) inventory data. 865 The default is none. 866 867 ``guid=uuid`` 868 value for the GUID for the BMC, in standard UUID format. If this 869 is set, get "Get GUID" command to the BMC will return it. 870 Otherwise "Get GUID" will return an error. 871 872``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 873 Add a connection to an external IPMI BMC simulator. Instead of 874 locally emulating the BMC like the above item, instead connect to an 875 external entity that provides the IPMI services. 876 877 A connection is made to an external BMC simulator. If you do this, 878 it is strongly recommended that you use the "reconnect=" chardev 879 option to reconnect to the simulator if the connection is lost. Note 880 that if this is not used carefully, it can be a security issue, as 881 the interface has the ability to send resets, NMIs, and power off 882 the VM. It's best if QEMU makes a connection to an external 883 simulator running on a secure port on localhost, so neither the 884 simulator nor QEMU is exposed to any outside network. 885 886 See the "lanserv/README.vm" file in the OpenIPMI library for more 887 details on the external interface. 888 889``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 890 Add a KCS IPMI interafce on the ISA bus. This also adds a 891 corresponding ACPI and SMBIOS entries, if appropriate. 892 893 ``bmc=id`` 894 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 895 above. 896 897 ``ioport=val`` 898 Define the I/O address of the interface. The default is 0xca0 899 for KCS. 900 901 ``irq=val`` 902 Define the interrupt to use. The default is 5. To disable 903 interrupts, set this to 0. 904 905``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 906 Like the KCS interface, but defines a BT interface. The default port 907 is 0xe4 and the default interrupt is 5. 908 909``-device pci-ipmi-kcs,bmc=id`` 910 Add a KCS IPMI interafce on the PCI bus. 911 912 ``bmc=id`` 913 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 914 915``-device pci-ipmi-bt,bmc=id`` 916 Like the KCS interface, but defines a BT interface on the PCI bus. 917ERST 918 919DEF("name", HAS_ARG, QEMU_OPTION_name, 920 "-name string1[,process=string2][,debug-threads=on|off]\n" 921 " set the name of the guest\n" 922 " string1 sets the window title and string2 the process name\n" 923 " When debug-threads is enabled, individual threads are given a separate name\n" 924 " NOTE: The thread names are for debugging and not a stable API.\n", 925 QEMU_ARCH_ALL) 926SRST 927``-name name`` 928 Sets the name of the guest. This name will be displayed in the SDL 929 window caption. The name will also be used for the VNC server. Also 930 optionally set the top visible process name in Linux. Naming of 931 individual threads can also be enabled on Linux to aid debugging. 932ERST 933 934DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 935 "-uuid %08x-%04x-%04x-%04x-%012x\n" 936 " specify machine UUID\n", QEMU_ARCH_ALL) 937SRST 938``-uuid uuid`` 939 Set system UUID. 940ERST 941 942DEFHEADING() 943 944DEFHEADING(Block device options:) 945 946DEF("fda", HAS_ARG, QEMU_OPTION_fda, 947 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 948DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 949SRST 950``-fda file`` 951 \ 952``-fdb file`` 953 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 954 the System Emulation Users Guide). 955ERST 956 957DEF("hda", HAS_ARG, QEMU_OPTION_hda, 958 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 959DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 960DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 961 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 962DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 963SRST 964``-hda file`` 965 \ 966``-hdb file`` 967 \ 968``-hdc file`` 969 \ 970``-hdd file`` 971 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 972 chapter in the System Emulation Users Guide). 973ERST 974 975DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 976 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 977 QEMU_ARCH_ALL) 978SRST 979``-cdrom file`` 980 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 981 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 982 as filename. 983ERST 984 985DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 986 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 987 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 988 " [,read-only=on|off][,auto-read-only=on|off]\n" 989 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 990 " [,driver specific parameters...]\n" 991 " configure a block backend\n", QEMU_ARCH_ALL) 992SRST 993``-blockdev option[,option[,option[,...]]]`` 994 Define a new block driver node. Some of the options apply to all 995 block drivers, other options are only accepted for a specific block 996 driver. See below for a list of generic options and options for the 997 most common block drivers. 998 999 Options that expect a reference to another node (e.g. ``file``) can 1000 be given in two ways. Either you specify the node name of an already 1001 existing node (file=node-name), or you define a new node inline, 1002 adding options for the referenced node after a dot 1003 (file.filename=path,file.aio=native). 1004 1005 A block driver node created with ``-blockdev`` can be used for a 1006 guest device by specifying its node name for the ``drive`` property 1007 in a ``-device`` argument that defines a block device. 1008 1009 ``Valid options for any block driver node:`` 1010 ``driver`` 1011 Specifies the block driver to use for the given node. 1012 1013 ``node-name`` 1014 This defines the name of the block driver node by which it 1015 will be referenced later. The name must be unique, i.e. it 1016 must not match the name of a different block driver node, or 1017 (if you use ``-drive`` as well) the ID of a drive. 1018 1019 If no node name is specified, it is automatically generated. 1020 The generated node name is not intended to be predictable 1021 and changes between QEMU invocations. For the top level, an 1022 explicit node name must be specified. 1023 1024 ``read-only`` 1025 Open the node read-only. Guest write attempts will fail. 1026 1027 Note that some block drivers support only read-only access, 1028 either generally or in certain configurations. In this case, 1029 the default value ``read-only=off`` does not work and the 1030 option must be specified explicitly. 1031 1032 ``auto-read-only`` 1033 If ``auto-read-only=on`` is set, QEMU may fall back to 1034 read-only usage even when ``read-only=off`` is requested, or 1035 even switch between modes as needed, e.g. depending on 1036 whether the image file is writable or whether a writing user 1037 is attached to the node. 1038 1039 ``force-share`` 1040 Override the image locking system of QEMU by forcing the 1041 node to utilize weaker shared access for permissions where 1042 it would normally request exclusive access. When there is 1043 the potential for multiple instances to have the same file 1044 open (whether this invocation of QEMU is the first or the 1045 second instance), both instances must permit shared access 1046 for the second instance to succeed at opening the file. 1047 1048 Enabling ``force-share=on`` requires ``read-only=on``. 1049 1050 ``cache.direct`` 1051 The host page cache can be avoided with ``cache.direct=on``. 1052 This will attempt to do disk IO directly to the guest's 1053 memory. QEMU may still perform an internal copy of the data. 1054 1055 ``cache.no-flush`` 1056 In case you don't care about data integrity over host 1057 failures, you can use ``cache.no-flush=on``. This option 1058 tells QEMU that it never needs to write any data to the disk 1059 but can instead keep things in cache. If anything goes 1060 wrong, like your host losing power, the disk storage getting 1061 disconnected accidentally, etc. your image will most 1062 probably be rendered unusable. 1063 1064 ``discard=discard`` 1065 discard is one of "ignore" (or "off") or "unmap" (or "on") 1066 and controls whether ``discard`` (also known as ``trim`` or 1067 ``unmap``) requests are ignored or passed to the filesystem. 1068 Some machine types may not support discard requests. 1069 1070 ``detect-zeroes=detect-zeroes`` 1071 detect-zeroes is "off", "on" or "unmap" and enables the 1072 automatic conversion of plain zero writes by the OS to 1073 driver specific optimized zero write commands. You may even 1074 choose "unmap" if discard is set to "unmap" to allow a zero 1075 write to be converted to an ``unmap`` operation. 1076 1077 ``Driver-specific options for file`` 1078 This is the protocol-level block driver for accessing regular 1079 files. 1080 1081 ``filename`` 1082 The path to the image file in the local filesystem 1083 1084 ``aio`` 1085 Specifies the AIO backend (threads/native/io_uring, 1086 default: threads) 1087 1088 ``locking`` 1089 Specifies whether the image file is protected with Linux OFD 1090 / POSIX locks. The default is to use the Linux Open File 1091 Descriptor API if available, otherwise no lock is applied. 1092 (auto/on/off, default: auto) 1093 1094 Example: 1095 1096 :: 1097 1098 -blockdev driver=file,node-name=disk,filename=disk.img 1099 1100 ``Driver-specific options for raw`` 1101 This is the image format block driver for raw images. It is 1102 usually stacked on top of a protocol level block driver such as 1103 ``file``. 1104 1105 ``file`` 1106 Reference to or definition of the data source block driver 1107 node (e.g. a ``file`` driver node) 1108 1109 Example 1: 1110 1111 :: 1112 1113 -blockdev driver=file,node-name=disk_file,filename=disk.img 1114 -blockdev driver=raw,node-name=disk,file=disk_file 1115 1116 Example 2: 1117 1118 :: 1119 1120 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1121 1122 ``Driver-specific options for qcow2`` 1123 This is the image format block driver for qcow2 images. It is 1124 usually stacked on top of a protocol level block driver such as 1125 ``file``. 1126 1127 ``file`` 1128 Reference to or definition of the data source block driver 1129 node (e.g. a ``file`` driver node) 1130 1131 ``backing`` 1132 Reference to or definition of the backing file block device 1133 (default is taken from the image file). It is allowed to 1134 pass ``null`` here in order to disable the default backing 1135 file. 1136 1137 ``lazy-refcounts`` 1138 Whether to enable the lazy refcounts feature (on/off; 1139 default is taken from the image file) 1140 1141 ``cache-size`` 1142 The maximum total size of the L2 table and refcount block 1143 caches in bytes (default: the sum of l2-cache-size and 1144 refcount-cache-size) 1145 1146 ``l2-cache-size`` 1147 The maximum size of the L2 table cache in bytes (default: if 1148 cache-size is not specified - 32M on Linux platforms, and 8M 1149 on non-Linux platforms; otherwise, as large as possible 1150 within the cache-size, while permitting the requested or the 1151 minimal refcount cache size) 1152 1153 ``refcount-cache-size`` 1154 The maximum size of the refcount block cache in bytes 1155 (default: 4 times the cluster size; or if cache-size is 1156 specified, the part of it which is not used for the L2 1157 cache) 1158 1159 ``cache-clean-interval`` 1160 Clean unused entries in the L2 and refcount caches. The 1161 interval is in seconds. The default value is 600 on 1162 supporting platforms, and 0 on other platforms. Setting it 1163 to 0 disables this feature. 1164 1165 ``pass-discard-request`` 1166 Whether discard requests to the qcow2 device should be 1167 forwarded to the data source (on/off; default: on if 1168 discard=unmap is specified, off otherwise) 1169 1170 ``pass-discard-snapshot`` 1171 Whether discard requests for the data source should be 1172 issued when a snapshot operation (e.g. deleting a snapshot) 1173 frees clusters in the qcow2 file (on/off; default: on) 1174 1175 ``pass-discard-other`` 1176 Whether discard requests for the data source should be 1177 issued on other occasions where a cluster gets freed 1178 (on/off; default: off) 1179 1180 ``overlap-check`` 1181 Which overlap checks to perform for writes to the image 1182 (none/constant/cached/all; default: cached). For details or 1183 finer granularity control refer to the QAPI documentation of 1184 ``blockdev-add``. 1185 1186 Example 1: 1187 1188 :: 1189 1190 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1191 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1192 1193 Example 2: 1194 1195 :: 1196 1197 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1198 1199 ``Driver-specific options for other drivers`` 1200 Please refer to the QAPI documentation of the ``blockdev-add`` 1201 QMP command. 1202ERST 1203 1204DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1205 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1206 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1207 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1208 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1209 " [,aio=threads|native|io_uring]\n" 1210 " [,readonly=on|off][,copy-on-read=on|off]\n" 1211 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1212 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1213 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1214 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1215 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1216 " [[,iops_size=is]]\n" 1217 " [[,group=g]]\n" 1218 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1219SRST 1220``-drive option[,option[,option[,...]]]`` 1221 Define a new drive. This includes creating a block driver node (the 1222 backend) as well as a guest device, and is mostly a shortcut for 1223 defining the corresponding ``-blockdev`` and ``-device`` options. 1224 1225 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1226 In addition, it knows the following options: 1227 1228 ``file=file`` 1229 This option defines which disk image (see the :ref:`disk images` 1230 chapter in the System Emulation Users Guide) to use with this drive. 1231 If the filename contains comma, you must double it (for instance, 1232 "file=my,,file" to use file "my,file"). 1233 1234 Special files such as iSCSI devices can be specified using 1235 protocol specific URLs. See the section for "Device URL Syntax" 1236 for more information. 1237 1238 ``if=interface`` 1239 This option defines on which type on interface the drive is 1240 connected. Available types are: ide, scsi, sd, mtd, floppy, 1241 pflash, virtio, none. 1242 1243 ``bus=bus,unit=unit`` 1244 These options define where is connected the drive by defining 1245 the bus number and the unit id. 1246 1247 ``index=index`` 1248 This option defines where is connected the drive by using an 1249 index in the list of available connectors of a given interface 1250 type. 1251 1252 ``media=media`` 1253 This option defines the type of the media: disk or cdrom. 1254 1255 ``snapshot=snapshot`` 1256 snapshot is "on" or "off" and controls snapshot mode for the 1257 given drive (see ``-snapshot``). 1258 1259 ``cache=cache`` 1260 cache is "none", "writeback", "unsafe", "directsync" or 1261 "writethrough" and controls how the host cache is used to access 1262 block data. This is a shortcut that sets the ``cache.direct`` 1263 and ``cache.no-flush`` options (as in ``-blockdev``), and 1264 additionally ``cache.writeback``, which provides a default for 1265 the ``write-cache`` option of block guest devices (as in 1266 ``-device``). The modes correspond to the following settings: 1267 1268 ============= =============== ============ ============== 1269 \ cache.writeback cache.direct cache.no-flush 1270 ============= =============== ============ ============== 1271 writeback on off off 1272 none on on off 1273 writethrough off off off 1274 directsync off on off 1275 unsafe on off on 1276 ============= =============== ============ ============== 1277 1278 The default mode is ``cache=writeback``. 1279 1280 ``aio=aio`` 1281 aio is "threads", "native", or "io_uring" and selects between pthread 1282 based disk I/O, native Linux AIO, or Linux io_uring API. 1283 1284 ``format=format`` 1285 Specify which disk format will be used rather than detecting the 1286 format. Can be used to specify format=raw to avoid interpreting 1287 an untrusted format header. 1288 1289 ``werror=action,rerror=action`` 1290 Specify which action to take on write and read errors. Valid 1291 actions are: "ignore" (ignore the error and try to continue), 1292 "stop" (pause QEMU), "report" (report the error to the guest), 1293 "enospc" (pause QEMU only if the host disk is full; report the 1294 error to the guest otherwise). The default setting is 1295 ``werror=enospc`` and ``rerror=report``. 1296 1297 ``copy-on-read=copy-on-read`` 1298 copy-on-read is "on" or "off" and enables whether to copy read 1299 backing file sectors into the image file. 1300 1301 ``bps=b,bps_rd=r,bps_wr=w`` 1302 Specify bandwidth throttling limits in bytes per second, either 1303 for all request types or for reads or writes only. Small values 1304 can lead to timeouts or hangs inside the guest. A safe minimum 1305 for disks is 2 MB/s. 1306 1307 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1308 Specify bursts in bytes per second, either for all request types 1309 or for reads or writes only. Bursts allow the guest I/O to spike 1310 above the limit temporarily. 1311 1312 ``iops=i,iops_rd=r,iops_wr=w`` 1313 Specify request rate limits in requests per second, either for 1314 all request types or for reads or writes only. 1315 1316 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1317 Specify bursts in requests per second, either for all request 1318 types or for reads or writes only. Bursts allow the guest I/O to 1319 spike above the limit temporarily. 1320 1321 ``iops_size=is`` 1322 Let every is bytes of a request count as a new request for iops 1323 throttling purposes. Use this option to prevent guests from 1324 circumventing iops limits by sending fewer but larger requests. 1325 1326 ``group=g`` 1327 Join a throttling quota group with given name g. All drives that 1328 are members of the same group are accounted for together. Use 1329 this option to prevent guests from circumventing throttling 1330 limits by using many small disks instead of a single larger 1331 disk. 1332 1333 By default, the ``cache.writeback=on`` mode is used. It will report 1334 data writes as completed as soon as the data is present in the host 1335 page cache. This is safe as long as your guest OS makes sure to 1336 correctly flush disk caches where needed. If your guest OS does not 1337 handle volatile disk write caches correctly and your host crashes or 1338 loses power, then the guest may experience data corruption. 1339 1340 For such guests, you should consider using ``cache.writeback=off``. 1341 This means that the host page cache will be used to read and write 1342 data, but write notification will be sent to the guest only after 1343 QEMU has made sure to flush each write to the disk. Be aware that 1344 this has a major impact on performance. 1345 1346 When using the ``-snapshot`` option, unsafe caching is always used. 1347 1348 Copy-on-read avoids accessing the same backing file sectors 1349 repeatedly and is useful when the backing file is over a slow 1350 network. By default copy-on-read is off. 1351 1352 Instead of ``-cdrom`` you can use: 1353 1354 .. parsed-literal:: 1355 1356 |qemu_system| -drive file=file,index=2,media=cdrom 1357 1358 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1359 1360 .. parsed-literal:: 1361 1362 |qemu_system| -drive file=file,index=0,media=disk 1363 |qemu_system| -drive file=file,index=1,media=disk 1364 |qemu_system| -drive file=file,index=2,media=disk 1365 |qemu_system| -drive file=file,index=3,media=disk 1366 1367 You can open an image using pre-opened file descriptors from an fd 1368 set: 1369 1370 .. parsed-literal:: 1371 1372 |qemu_system| \\ 1373 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1374 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1375 -drive file=/dev/fdset/2,index=0,media=disk 1376 1377 You can connect a CDROM to the slave of ide0: 1378 1379 .. parsed-literal:: 1380 1381 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1382 1383 If you don't specify the "file=" argument, you define an empty 1384 drive: 1385 1386 .. parsed-literal:: 1387 1388 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1389 1390 Instead of ``-fda``, ``-fdb``, you can use: 1391 1392 .. parsed-literal:: 1393 1394 |qemu_system_x86| -drive file=file,index=0,if=floppy 1395 |qemu_system_x86| -drive file=file,index=1,if=floppy 1396 1397 By default, interface is "ide" and index is automatically 1398 incremented: 1399 1400 .. parsed-literal:: 1401 1402 |qemu_system_x86| -drive file=a -drive file=b" 1403 1404 is interpreted like: 1405 1406 .. parsed-literal:: 1407 1408 |qemu_system_x86| -hda a -hdb b 1409ERST 1410 1411DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1412 "-mtdblock file use 'file' as on-board Flash memory image\n", 1413 QEMU_ARCH_ALL) 1414SRST 1415``-mtdblock file`` 1416 Use file as on-board Flash memory image. 1417ERST 1418 1419DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1420 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1421SRST 1422``-sd file`` 1423 Use file as SecureDigital card image. 1424ERST 1425 1426DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1427 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1428SRST 1429``-pflash file`` 1430 Use file as a parallel flash image. 1431ERST 1432 1433DEF("snapshot", 0, QEMU_OPTION_snapshot, 1434 "-snapshot write to temporary files instead of disk image files\n", 1435 QEMU_ARCH_ALL) 1436SRST 1437``-snapshot`` 1438 Write to temporary files instead of disk image files. In this case, 1439 the raw disk image you use is not written back. You can however 1440 force the write back by pressing C-a s (see the :ref:`disk images` 1441 chapter in the System Emulation Users Guide). 1442ERST 1443 1444DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1445 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1446 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1447 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1448 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1449 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1450 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1451 " [[,throttling.iops-size=is]]\n" 1452 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1453 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1454 "-fsdev synth,id=id\n", 1455 QEMU_ARCH_ALL) 1456 1457SRST 1458``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1459 \ 1460``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1461 \ 1462``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1463 \ 1464``-fsdev synth,id=id[,readonly=on]`` 1465 Define a new file system device. Valid options are: 1466 1467 ``local`` 1468 Accesses to the filesystem are done by QEMU. 1469 1470 ``proxy`` 1471 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1472 1473 ``synth`` 1474 Synthetic filesystem, only used by QTests. 1475 1476 ``id=id`` 1477 Specifies identifier for this device. 1478 1479 ``path=path`` 1480 Specifies the export path for the file system device. Files 1481 under this path will be available to the 9p client on the guest. 1482 1483 ``security_model=security_model`` 1484 Specifies the security model to be used for this export path. 1485 Supported security models are "passthrough", "mapped-xattr", 1486 "mapped-file" and "none". In "passthrough" security model, files 1487 are stored using the same credentials as they are created on the 1488 guest. This requires QEMU to run as root. In "mapped-xattr" 1489 security model, some of the file attributes like uid, gid, mode 1490 bits and link target are stored as file attributes. For 1491 "mapped-file" these attributes are stored in the hidden 1492 .virtfs\_metadata directory. Directories exported by this 1493 security model cannot interact with other unix tools. "none" 1494 security model is same as passthrough except the sever won't 1495 report failures if it fails to set file attributes like 1496 ownership. Security model is mandatory only for local fsdriver. 1497 Other fsdrivers (like proxy) don't take security model as a 1498 parameter. 1499 1500 ``writeout=writeout`` 1501 This is an optional argument. The only supported value is 1502 "immediate". This means that host page cache will be used to 1503 read and write data but write notification will be sent to the 1504 guest only when the data has been reported as written by the 1505 storage subsystem. 1506 1507 ``readonly=on`` 1508 Enables exporting 9p share as a readonly mount for guests. By 1509 default read-write access is given. 1510 1511 ``socket=socket`` 1512 Enables proxy filesystem driver to use passed socket file for 1513 communicating with virtfs-proxy-helper(1). 1514 1515 ``sock_fd=sock_fd`` 1516 Enables proxy filesystem driver to use passed socket descriptor 1517 for communicating with virtfs-proxy-helper(1). Usually a helper 1518 like libvirt will create socketpair and pass one of the fds as 1519 sock\_fd. 1520 1521 ``fmode=fmode`` 1522 Specifies the default mode for newly created files on the host. 1523 Works only with security models "mapped-xattr" and 1524 "mapped-file". 1525 1526 ``dmode=dmode`` 1527 Specifies the default mode for newly created directories on the 1528 host. Works only with security models "mapped-xattr" and 1529 "mapped-file". 1530 1531 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1532 Specify bandwidth throttling limits in bytes per second, either 1533 for all request types or for reads or writes only. 1534 1535 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1536 Specify bursts in bytes per second, either for all request types 1537 or for reads or writes only. Bursts allow the guest I/O to spike 1538 above the limit temporarily. 1539 1540 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1541 Specify request rate limits in requests per second, either for 1542 all request types or for reads or writes only. 1543 1544 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1545 Specify bursts in requests per second, either for all request 1546 types or for reads or writes only. Bursts allow the guest I/O to 1547 spike above the limit temporarily. 1548 1549 ``throttling.iops-size=is`` 1550 Let every is bytes of a request count as a new request for iops 1551 throttling purposes. 1552 1553 -fsdev option is used along with -device driver "virtio-9p-...". 1554 1555``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1556 Options for virtio-9p-... driver are: 1557 1558 ``type`` 1559 Specifies the variant to be used. Supported values are "pci", 1560 "ccw" or "device", depending on the machine type. 1561 1562 ``fsdev=id`` 1563 Specifies the id value specified along with -fsdev option. 1564 1565 ``mount_tag=mount_tag`` 1566 Specifies the tag name to be used by the guest to mount this 1567 export point. 1568ERST 1569 1570DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1571 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1572 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1573 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1574 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1575 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1576 QEMU_ARCH_ALL) 1577 1578SRST 1579``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1580 \ 1581``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1582 \ 1583``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1584 \ 1585``-virtfs synth,mount_tag=mount_tag`` 1586 Define a new virtual filesystem device and expose it to the guest using 1587 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1588 directory on host is made directly accessible by guest as a pass-through 1589 file system by using the 9P network protocol for communication between 1590 host and guests, if desired even accessible, shared by several guests 1591 simultaniously. 1592 1593 Note that ``-virtfs`` is actually just a convenience shortcut for its 1594 generalized form ``-fsdev -device virtio-9p-pci``. 1595 1596 The general form of pass-through file system options are: 1597 1598 ``local`` 1599 Accesses to the filesystem are done by QEMU. 1600 1601 ``proxy`` 1602 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1603 1604 ``synth`` 1605 Synthetic filesystem, only used by QTests. 1606 1607 ``id=id`` 1608 Specifies identifier for the filesystem device 1609 1610 ``path=path`` 1611 Specifies the export path for the file system device. Files 1612 under this path will be available to the 9p client on the guest. 1613 1614 ``security_model=security_model`` 1615 Specifies the security model to be used for this export path. 1616 Supported security models are "passthrough", "mapped-xattr", 1617 "mapped-file" and "none". In "passthrough" security model, files 1618 are stored using the same credentials as they are created on the 1619 guest. This requires QEMU to run as root. In "mapped-xattr" 1620 security model, some of the file attributes like uid, gid, mode 1621 bits and link target are stored as file attributes. For 1622 "mapped-file" these attributes are stored in the hidden 1623 .virtfs\_metadata directory. Directories exported by this 1624 security model cannot interact with other unix tools. "none" 1625 security model is same as passthrough except the sever won't 1626 report failures if it fails to set file attributes like 1627 ownership. Security model is mandatory only for local fsdriver. 1628 Other fsdrivers (like proxy) don't take security model as a 1629 parameter. 1630 1631 ``writeout=writeout`` 1632 This is an optional argument. The only supported value is 1633 "immediate". This means that host page cache will be used to 1634 read and write data but write notification will be sent to the 1635 guest only when the data has been reported as written by the 1636 storage subsystem. 1637 1638 ``readonly=on`` 1639 Enables exporting 9p share as a readonly mount for guests. By 1640 default read-write access is given. 1641 1642 ``socket=socket`` 1643 Enables proxy filesystem driver to use passed socket file for 1644 communicating with virtfs-proxy-helper(1). Usually a helper like 1645 libvirt will create socketpair and pass one of the fds as 1646 sock\_fd. 1647 1648 ``sock_fd`` 1649 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1650 socket descriptor for interfacing with virtfs-proxy-helper(1). 1651 1652 ``fmode=fmode`` 1653 Specifies the default mode for newly created files on the host. 1654 Works only with security models "mapped-xattr" and 1655 "mapped-file". 1656 1657 ``dmode=dmode`` 1658 Specifies the default mode for newly created directories on the 1659 host. Works only with security models "mapped-xattr" and 1660 "mapped-file". 1661 1662 ``mount_tag=mount_tag`` 1663 Specifies the tag name to be used by the guest to mount this 1664 export point. 1665 1666 ``multidevs=multidevs`` 1667 Specifies how to deal with multiple devices being shared with a 1668 9p export. Supported behaviours are either "remap", "forbid" or 1669 "warn". The latter is the default behaviour on which virtfs 9p 1670 expects only one device to be shared with the same export, and 1671 if more than one device is shared and accessed via the same 9p 1672 export then only a warning message is logged (once) by qemu on 1673 host side. In order to avoid file ID collisions on guest you 1674 should either create a separate virtfs export for each device to 1675 be shared with guests (recommended way) or you might use "remap" 1676 instead which allows you to share multiple devices with only one 1677 export instead, which is achieved by remapping the original 1678 inode numbers from host to guest in a way that would prevent 1679 such collisions. Remapping inodes in such use cases is required 1680 because the original device IDs from host are never passed and 1681 exposed on guest. Instead all files of an export shared with 1682 virtfs always share the same device id on guest. So two files 1683 with identical inode numbers but from actually different devices 1684 on host would otherwise cause a file ID collision and hence 1685 potential misbehaviours on guest. "forbid" on the other hand 1686 assumes like "warn" that only one device is shared by the same 1687 export, however it will not only log a warning message but also 1688 deny access to additional devices on guest. Note though that 1689 "forbid" does currently not block all possible file access 1690 operations (e.g. readdir() would still return entries from other 1691 devices). 1692ERST 1693 1694DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1695 "-iscsi [user=user][,password=password]\n" 1696 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1697 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1698 " [,timeout=timeout]\n" 1699 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1700 1701SRST 1702``-iscsi`` 1703 Configure iSCSI session parameters. 1704ERST 1705 1706DEFHEADING() 1707 1708DEFHEADING(USB convenience options:) 1709 1710DEF("usb", 0, QEMU_OPTION_usb, 1711 "-usb enable on-board USB host controller (if not enabled by default)\n", 1712 QEMU_ARCH_ALL) 1713SRST 1714``-usb`` 1715 Enable USB emulation on machine types with an on-board USB host 1716 controller (if not enabled by default). Note that on-board USB host 1717 controllers may not support USB 3.0. In this case 1718 ``-device qemu-xhci`` can be used instead on machines with PCI. 1719ERST 1720 1721DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1722 "-usbdevice name add the host or guest USB device 'name'\n", 1723 QEMU_ARCH_ALL) 1724SRST 1725``-usbdevice devname`` 1726 Add the USB device devname, and enable an on-board USB controller 1727 if possible and necessary (just like it can be done via 1728 ``-machine usb=on``). Note that this option is mainly intended for 1729 the user's convenience only. More fine-grained control can be 1730 achieved by selecting a USB host controller (if necessary) and the 1731 desired USB device via the ``-device`` option instead. For example, 1732 instead of using ``-usbdevice mouse`` it is possible to use 1733 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1734 to a USB 3.0 controller instead (at least on machines that support 1735 PCI and do not have an USB controller enabled by default yet). 1736 For more details, see the chapter about 1737 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1738 Possible devices for devname are: 1739 1740 ``braille`` 1741 Braille device. This will use BrlAPI to display the braille 1742 output on a real or fake device (i.e. it also creates a 1743 corresponding ``braille`` chardev automatically beside the 1744 ``usb-braille`` USB device). 1745 1746 ``ccid`` 1747 Smartcard reader device 1748 1749 ``keyboard`` 1750 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1751 1752 ``mouse`` 1753 Virtual Mouse. This will override the PS/2 mouse emulation when 1754 activated. 1755 1756 ``tablet`` 1757 Pointer device that uses absolute coordinates (like a 1758 touchscreen). This means QEMU is able to report the mouse 1759 position without having to grab the mouse. Also overrides the 1760 PS/2 mouse emulation when activated. 1761 1762 ``wacom-tablet`` 1763 Wacom PenPartner USB tablet. 1764 1765 1766ERST 1767 1768DEFHEADING() 1769 1770DEFHEADING(Display options:) 1771 1772DEF("display", HAS_ARG, QEMU_OPTION_display, 1773#if defined(CONFIG_SPICE) 1774 "-display spice-app[,gl=on|off]\n" 1775#endif 1776#if defined(CONFIG_SDL) 1777 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1778 " [,window_close=on|off][,gl=on|core|es|off]\n" 1779#endif 1780#if defined(CONFIG_GTK) 1781 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1782#endif 1783#if defined(CONFIG_VNC) 1784 "-display vnc=<display>[,<optargs>]\n" 1785#endif 1786#if defined(CONFIG_CURSES) 1787 "-display curses[,charset=<encoding>]\n" 1788#endif 1789#if defined(CONFIG_OPENGL) 1790 "-display egl-headless[,rendernode=<file>]\n" 1791#endif 1792 "-display none\n" 1793 " select display backend type\n" 1794 " The default display is equivalent to\n " 1795#if defined(CONFIG_GTK) 1796 "\"-display gtk\"\n" 1797#elif defined(CONFIG_SDL) 1798 "\"-display sdl\"\n" 1799#elif defined(CONFIG_COCOA) 1800 "\"-display cocoa\"\n" 1801#elif defined(CONFIG_VNC) 1802 "\"-vnc localhost:0,to=99,id=default\"\n" 1803#else 1804 "\"-display none\"\n" 1805#endif 1806 , QEMU_ARCH_ALL) 1807SRST 1808``-display type`` 1809 Select type of display to use. This option is a replacement for the 1810 old style -sdl/-curses/... options. Use ``-display help`` to list 1811 the available display types. Valid values for type are 1812 1813 ``sdl`` 1814 Display video output via SDL (usually in a separate graphics 1815 window; see the SDL documentation for other possibilities). 1816 1817 ``curses`` 1818 Display video output via curses. For graphics device models 1819 which support a text mode, QEMU can display this output using a 1820 curses/ncurses interface. Nothing is displayed when the graphics 1821 device is in graphical mode or if the graphics device does not 1822 support a text mode. Generally only the VGA device models 1823 support text mode. The font charset used by the guest can be 1824 specified with the ``charset`` option, for example 1825 ``charset=CP850`` for IBM CP850 encoding. The default is 1826 ``CP437``. 1827 1828 ``none`` 1829 Do not display video output. The guest will still see an 1830 emulated graphics card, but its output will not be displayed to 1831 the QEMU user. This option differs from the -nographic option in 1832 that it only affects what is done with video output; -nographic 1833 also changes the destination of the serial and parallel port 1834 data. 1835 1836 ``gtk`` 1837 Display video output in a GTK window. This interface provides 1838 drop-down menus and other UI elements to configure and control 1839 the VM during runtime. 1840 1841 ``vnc`` 1842 Start a VNC server on display <arg> 1843 1844 ``egl-headless`` 1845 Offload all OpenGL operations to a local DRI device. For any 1846 graphical display, this display needs to be paired with either 1847 VNC or SPICE displays. 1848 1849 ``spice-app`` 1850 Start QEMU as a Spice server and launch the default Spice client 1851 application. The Spice server will redirect the serial consoles 1852 and QEMU monitors. (Since 4.0) 1853ERST 1854 1855DEF("nographic", 0, QEMU_OPTION_nographic, 1856 "-nographic disable graphical output and redirect serial I/Os to console\n", 1857 QEMU_ARCH_ALL) 1858SRST 1859``-nographic`` 1860 Normally, if QEMU is compiled with graphical window support, it 1861 displays output such as guest graphics, guest console, and the QEMU 1862 monitor in a window. With this option, you can totally disable 1863 graphical output so that QEMU is a simple command line application. 1864 The emulated serial port is redirected on the console and muxed with 1865 the monitor (unless redirected elsewhere explicitly). Therefore, you 1866 can still use QEMU to debug a Linux kernel with a serial console. 1867 Use C-a h for help on switching between the console and monitor. 1868ERST 1869 1870DEF("curses", 0, QEMU_OPTION_curses, 1871 "-curses shorthand for -display curses\n", 1872 QEMU_ARCH_ALL) 1873SRST 1874``-curses`` 1875 Normally, if QEMU is compiled with graphical window support, it 1876 displays output such as guest graphics, guest console, and the QEMU 1877 monitor in a window. With this option, QEMU can display the VGA 1878 output when in text mode using a curses/ncurses interface. Nothing 1879 is displayed in graphical mode. 1880ERST 1881 1882DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1883 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1884 QEMU_ARCH_ALL) 1885SRST 1886``-alt-grab`` 1887 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1888 this also affects the special keys (for fullscreen, monitor-mode 1889 switching, etc). 1890ERST 1891 1892DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1893 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1894 QEMU_ARCH_ALL) 1895SRST 1896``-ctrl-grab`` 1897 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1898 also affects the special keys (for fullscreen, monitor-mode 1899 switching, etc). 1900ERST 1901 1902DEF("no-quit", 0, QEMU_OPTION_no_quit, 1903 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1904SRST 1905``-no-quit`` 1906 Disable SDL window close capability. 1907ERST 1908 1909DEF("sdl", 0, QEMU_OPTION_sdl, 1910 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1911SRST 1912``-sdl`` 1913 Enable SDL. 1914ERST 1915 1916DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1917 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1918 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1919 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1920 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1921 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1922 " [,tls-ciphers=<list>]\n" 1923 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1924 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1925 " [,sasl=on|off][,password=<secret>][,disable-ticketing=on|off]\n" 1926 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1927 " [,jpeg-wan-compression=[auto|never|always]]\n" 1928 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1929 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1930 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1931 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1932 " [,gl=[on|off]][,rendernode=<file>]\n" 1933 " enable spice\n" 1934 " at least one of {port, tls-port} is mandatory\n", 1935 QEMU_ARCH_ALL) 1936SRST 1937``-spice option[,option[,...]]`` 1938 Enable the spice remote desktop protocol. Valid options are 1939 1940 ``port=<nr>`` 1941 Set the TCP port spice is listening on for plaintext channels. 1942 1943 ``addr=<addr>`` 1944 Set the IP address spice is listening on. Default is any 1945 address. 1946 1947 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1948 Force using the specified IP version. 1949 1950 ``password=<secret>`` 1951 Set the password you need to authenticate. 1952 1953 ``sasl=on|off`` 1954 Require that the client use SASL to authenticate with the spice. 1955 The exact choice of authentication method used is controlled 1956 from the system / user's SASL configuration file for the 'qemu' 1957 service. This is typically found in /etc/sasl2/qemu.conf. If 1958 running QEMU as an unprivileged user, an environment variable 1959 SASL\_CONF\_PATH can be used to make it search alternate 1960 locations for the service config. While some SASL auth methods 1961 can also provide data encryption (eg GSSAPI), it is recommended 1962 that SASL always be combined with the 'tls' and 'x509' settings 1963 to enable use of SSL and server certificates. This ensures a 1964 data encryption preventing compromise of authentication 1965 credentials. 1966 1967 ``disable-ticketing=on|off`` 1968 Allow client connects without authentication. 1969 1970 ``disable-copy-paste=on|off`` 1971 Disable copy paste between the client and the guest. 1972 1973 ``disable-agent-file-xfer=on|off`` 1974 Disable spice-vdagent based file-xfer between the client and the 1975 guest. 1976 1977 ``tls-port=<nr>`` 1978 Set the TCP port spice is listening on for encrypted channels. 1979 1980 ``x509-dir=<dir>`` 1981 Set the x509 file directory. Expects same filenames as -vnc 1982 $display,x509=$dir 1983 1984 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 1985 The x509 file names can also be configured individually. 1986 1987 ``tls-ciphers=<list>`` 1988 Specify which ciphers to use. 1989 1990 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 1991 Force specific channel to be used with or without TLS 1992 encryption. The options can be specified multiple times to 1993 configure multiple channels. The special name "default" can be 1994 used to set the default mode. For channels which are not 1995 explicitly forced into one mode the spice client is allowed to 1996 pick tls/plaintext as he pleases. 1997 1998 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 1999 Configure image compression (lossless). Default is auto\_glz. 2000 2001 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2002 Configure wan image compression (lossy for slow links). Default 2003 is auto. 2004 2005 ``streaming-video=[off|all|filter]`` 2006 Configure video stream detection. Default is off. 2007 2008 ``agent-mouse=[on|off]`` 2009 Enable/disable passing mouse events via vdagent. Default is on. 2010 2011 ``playback-compression=[on|off]`` 2012 Enable/disable audio stream compression (using celt 0.5.1). 2013 Default is on. 2014 2015 ``seamless-migration=[on|off]`` 2016 Enable/disable spice seamless migration. Default is off. 2017 2018 ``gl=[on|off]`` 2019 Enable/disable OpenGL context. Default is off. 2020 2021 ``rendernode=<file>`` 2022 DRM render node for OpenGL rendering. If not specified, it will 2023 pick the first available. (Since 2.9) 2024ERST 2025 2026DEF("portrait", 0, QEMU_OPTION_portrait, 2027 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2028 QEMU_ARCH_ALL) 2029SRST 2030``-portrait`` 2031 Rotate graphical output 90 deg left (only PXA LCD). 2032ERST 2033 2034DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2035 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2036 QEMU_ARCH_ALL) 2037SRST 2038``-rotate deg`` 2039 Rotate graphical output some deg left (only PXA LCD). 2040ERST 2041 2042DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2043 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2044 " select video card type\n", QEMU_ARCH_ALL) 2045SRST 2046``-vga type`` 2047 Select type of VGA card to emulate. Valid values for type are 2048 2049 ``cirrus`` 2050 Cirrus Logic GD5446 Video card. All Windows versions starting 2051 from Windows 95 should recognize and use this graphic card. For 2052 optimal performances, use 16 bit color depth in the guest and 2053 the host OS. (This card was the default before QEMU 2.2) 2054 2055 ``std`` 2056 Standard VGA card with Bochs VBE extensions. If your guest OS 2057 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2058 you want to use high resolution modes (>= 1280x1024x16) then you 2059 should use this option. (This card is the default since QEMU 2060 2.2) 2061 2062 ``vmware`` 2063 VMWare SVGA-II compatible adapter. Use it if you have 2064 sufficiently recent XFree86/XOrg server or Windows guest with a 2065 driver for this card. 2066 2067 ``qxl`` 2068 QXL paravirtual graphic card. It is VGA compatible (including 2069 VESA 2.0 VBE support). Works best with qxl guest drivers 2070 installed though. Recommended choice when using the spice 2071 protocol. 2072 2073 ``tcx`` 2074 (sun4m only) Sun TCX framebuffer. This is the default 2075 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2076 colour depths at a fixed resolution of 1024x768. 2077 2078 ``cg3`` 2079 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2080 framebuffer for sun4m machines available in both 1024x768 2081 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2082 wishing to run older Solaris versions. 2083 2084 ``virtio`` 2085 Virtio VGA card. 2086 2087 ``none`` 2088 Disable VGA card. 2089ERST 2090 2091DEF("full-screen", 0, QEMU_OPTION_full_screen, 2092 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2093SRST 2094``-full-screen`` 2095 Start in full screen. 2096ERST 2097 2098DEF("g", HAS_ARG, QEMU_OPTION_g , 2099 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2100 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2101SRST 2102``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2103 Set the initial graphical resolution and depth (PPC, SPARC only). 2104 2105 For PPC the default is 800x600x32. 2106 2107 For SPARC with the TCX graphics device, the default is 1024x768x8 2108 with the option of 1024x768x24. For cgthree, the default is 2109 1024x768x8 with the option of 1152x900x8 for people who wish to use 2110 OBP. 2111ERST 2112 2113DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2114 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2115SRST 2116``-vnc display[,option[,option[,...]]]`` 2117 Normally, if QEMU is compiled with graphical window support, it 2118 displays output such as guest graphics, guest console, and the QEMU 2119 monitor in a window. With this option, you can have QEMU listen on 2120 VNC display display and redirect the VGA display over the VNC 2121 session. It is very useful to enable the usb tablet device when 2122 using this option (option ``-device usb-tablet``). When using the 2123 VNC display, you must use the ``-k`` parameter to set the keyboard 2124 layout if you are not using en-us. Valid syntax for the display is 2125 2126 ``to=L`` 2127 With this option, QEMU will try next available VNC displays, 2128 until the number L, if the origianlly defined "-vnc display" is 2129 not available, e.g. port 5900+display is already used by another 2130 application. By default, to=0. 2131 2132 ``host:d`` 2133 TCP connections will only be allowed from host on display d. By 2134 convention the TCP port is 5900+d. Optionally, host can be 2135 omitted in which case the server will accept connections from 2136 any host. 2137 2138 ``unix:path`` 2139 Connections will be allowed over UNIX domain sockets where path 2140 is the location of a unix socket to listen for connections on. 2141 2142 ``none`` 2143 VNC is initialized but not started. The monitor ``change`` 2144 command can be used to later start the VNC server. 2145 2146 Following the display value there may be one or more option flags 2147 separated by commas. Valid options are 2148 2149 ``reverse=on|off`` 2150 Connect to a listening VNC client via a "reverse" connection. 2151 The client is specified by the display. For reverse network 2152 connections (host:d,``reverse``), the d argument is a TCP port 2153 number, not a display number. 2154 2155 ``websocket=on|off`` 2156 Opens an additional TCP listening port dedicated to VNC 2157 Websocket connections. If a bare websocket option is given, the 2158 Websocket port is 5700+display. An alternative port can be 2159 specified with the syntax ``websocket``\ =port. 2160 2161 If host is specified connections will only be allowed from this 2162 host. It is possible to control the websocket listen address 2163 independently, using the syntax ``websocket``\ =host:port. 2164 2165 If no TLS credentials are provided, the websocket connection 2166 runs in unencrypted mode. If TLS credentials are provided, the 2167 websocket connection requires encrypted client connections. 2168 2169 ``password=on|off`` 2170 Require that password based authentication is used for client 2171 connections. 2172 2173 The password must be set separately using the ``set_password`` 2174 command in the :ref:`QEMU monitor`. The 2175 syntax to change your password is: 2176 ``set_password <protocol> <password>`` where <protocol> could be 2177 either "vnc" or "spice". 2178 2179 If you would like to change <protocol> password expiration, you 2180 should use ``expire_password <protocol> <expiration-time>`` 2181 where expiration time could be one of the following options: 2182 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2183 make password expire in 60 seconds, or 1335196800 to make 2184 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2185 this date and time). 2186 2187 You can also use keywords "now" or "never" for the expiration 2188 time to allow <protocol> password to expire immediately or never 2189 expire. 2190 2191 ``tls-creds=ID`` 2192 Provides the ID of a set of TLS credentials to use to secure the 2193 VNC server. They will apply to both the normal VNC server socket 2194 and the websocket socket (if enabled). Setting TLS credentials 2195 will cause the VNC server socket to enable the VeNCrypt auth 2196 mechanism. The credentials should have been previously created 2197 using the ``-object tls-creds`` argument. 2198 2199 ``tls-authz=ID`` 2200 Provides the ID of the QAuthZ authorization object against which 2201 the client's x509 distinguished name will validated. This object 2202 is only resolved at time of use, so can be deleted and recreated 2203 on the fly while the VNC server is active. If missing, it will 2204 default to denying access. 2205 2206 ``sasl=on|off`` 2207 Require that the client use SASL to authenticate with the VNC 2208 server. The exact choice of authentication method used is 2209 controlled from the system / user's SASL configuration file for 2210 the 'qemu' service. This is typically found in 2211 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2212 an environment variable SASL\_CONF\_PATH can be used to make it 2213 search alternate locations for the service config. While some 2214 SASL auth methods can also provide data encryption (eg GSSAPI), 2215 it is recommended that SASL always be combined with the 'tls' 2216 and 'x509' settings to enable use of SSL and server 2217 certificates. This ensures a data encryption preventing 2218 compromise of authentication credentials. See the 2219 :ref:`VNC security` section in the System Emulation Users Guide 2220 for details on using SASL authentication. 2221 2222 ``sasl-authz=ID`` 2223 Provides the ID of the QAuthZ authorization object against which 2224 the client's SASL username will validated. This object is only 2225 resolved at time of use, so can be deleted and recreated on the 2226 fly while the VNC server is active. If missing, it will default 2227 to denying access. 2228 2229 ``acl=on|off`` 2230 Legacy method for enabling authorization of clients against the 2231 x509 distinguished name and SASL username. It results in the 2232 creation of two ``authz-list`` objects with IDs of 2233 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2234 objects must be configured with the HMP ACL commands. 2235 2236 This option is deprecated and should no longer be used. The new 2237 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2238 2239 ``lossy=on|off`` 2240 Enable lossy compression methods (gradient, JPEG, ...). If this 2241 option is set, VNC client may receive lossy framebuffer updates 2242 depending on its encoding settings. Enabling this option can 2243 save a lot of bandwidth at the expense of quality. 2244 2245 ``non-adaptive=on|off`` 2246 Disable adaptive encodings. Adaptive encodings are enabled by 2247 default. An adaptive encoding will try to detect frequently 2248 updated screen regions, and send updates in these regions using 2249 a lossy encoding (like JPEG). This can be really helpful to save 2250 bandwidth when playing videos. Disabling adaptive encodings 2251 restores the original static behavior of encodings like Tight. 2252 2253 ``share=[allow-exclusive|force-shared|ignore]`` 2254 Set display sharing policy. 'allow-exclusive' allows clients to 2255 ask for exclusive access. As suggested by the rfb spec this is 2256 implemented by dropping other connections. Connecting multiple 2257 clients in parallel requires all clients asking for a shared 2258 session (vncviewer: -shared switch). This is the default. 2259 'force-shared' disables exclusive client access. Useful for 2260 shared desktop sessions, where you don't want someone forgetting 2261 specify -shared disconnect everybody else. 'ignore' completely 2262 ignores the shared flag and allows everybody connect 2263 unconditionally. Doesn't conform to the rfb spec but is 2264 traditional QEMU behavior. 2265 2266 ``key-delay-ms`` 2267 Set keyboard delay, for key down and key up events, in 2268 milliseconds. Default is 10. Keyboards are low-bandwidth 2269 devices, so this slowdown can help the device and guest to keep 2270 up and not lose events in case events are arriving in bulk. 2271 Possible causes for the latter are flaky network connections, or 2272 scripts for automated testing. 2273 2274 ``audiodev=audiodev`` 2275 Use the specified audiodev when the VNC client requests audio 2276 transmission. When not using an -audiodev argument, this option 2277 must be omitted, otherwise is must be present and specify a 2278 valid audiodev. 2279 2280 ``power-control=on|off`` 2281 Permit the remote client to issue shutdown, reboot or reset power 2282 control requests. 2283ERST 2284 2285ARCHHEADING(, QEMU_ARCH_I386) 2286 2287ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2288 2289DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2290 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2291 QEMU_ARCH_I386) 2292SRST 2293``-win2k-hack`` 2294 Use it when installing Windows 2000 to avoid a disk full bug. After 2295 Windows 2000 is installed, you no longer need this option (this 2296 option slows down the IDE transfers). 2297ERST 2298 2299DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2300 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2301 QEMU_ARCH_I386) 2302SRST 2303``-no-fd-bootchk`` 2304 Disable boot signature checking for floppy disks in BIOS. May be 2305 needed to boot from old floppy disks. 2306ERST 2307 2308DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2309 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2310SRST 2311``-no-acpi`` 2312 Disable ACPI (Advanced Configuration and Power Interface) support. 2313 Use it if your guest OS complains about ACPI problems (PC target 2314 machine only). 2315ERST 2316 2317DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2318 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2319SRST 2320``-no-hpet`` 2321 Disable HPET support. 2322ERST 2323 2324DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2325 "-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" 2326 " ACPI table description\n", QEMU_ARCH_I386) 2327SRST 2328``-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]...]`` 2329 Add ACPI table with specified header fields and context from 2330 specified files. For file=, take whole ACPI table from the specified 2331 files, including all ACPI headers (possible overridden by other 2332 options). For data=, only data portion of the table is used, all 2333 header information is specified in the command line. If a SLIC table 2334 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2335 fields will override the same in the RSDT and the FADT (a.k.a. 2336 FACP), in order to ensure the field matches required by the 2337 Microsoft SLIC spec and the ACPI spec. 2338ERST 2339 2340DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2341 "-smbios file=binary\n" 2342 " load SMBIOS entry from binary file\n" 2343 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2344 " [,uefi=on|off]\n" 2345 " specify SMBIOS type 0 fields\n" 2346 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2347 " [,uuid=uuid][,sku=str][,family=str]\n" 2348 " specify SMBIOS type 1 fields\n" 2349 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2350 " [,asset=str][,location=str]\n" 2351 " specify SMBIOS type 2 fields\n" 2352 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2353 " [,sku=str]\n" 2354 " specify SMBIOS type 3 fields\n" 2355 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2356 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2357 " specify SMBIOS type 4 fields\n" 2358 "-smbios type=11[,value=str][,path=filename]\n" 2359 " specify SMBIOS type 11 fields\n" 2360 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2361 " [,asset=str][,part=str][,speed=%d]\n" 2362 " specify SMBIOS type 17 fields\n", 2363 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2364SRST 2365``-smbios file=binary`` 2366 Load SMBIOS entry from binary file. 2367 2368``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2369 Specify SMBIOS type 0 fields 2370 2371``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2372 Specify SMBIOS type 1 fields 2373 2374``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2375 Specify SMBIOS type 2 fields 2376 2377``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2378 Specify SMBIOS type 3 fields 2379 2380``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2381 Specify SMBIOS type 4 fields 2382 2383``-smbios type=11[,value=str][,path=filename]`` 2384 Specify SMBIOS type 11 fields 2385 2386 This argument can be repeated multiple times, and values are added in the order they are parsed. 2387 Applications intending to use OEM strings data are encouraged to use their application name as 2388 a prefix for the value string. This facilitates passing information for multiple applications 2389 concurrently. 2390 2391 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2392 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2393 2394 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2395 the SMBIOS table in the order in which they appear. 2396 2397 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2398 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2399 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2400 data set, for example, by specifying the serial ID of a block device. 2401 2402 An example passing three strings is 2403 2404 .. parsed-literal:: 2405 2406 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2407 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2408 path=/some/file/with/oemstringsdata.txt 2409 2410 In the guest OS this is visible with the ``dmidecode`` command 2411 2412 .. parsed-literal:: 2413 2414 $ dmidecode -t 11 2415 Handle 0x0E00, DMI type 11, 5 bytes 2416 OEM Strings 2417 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2418 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2419 String 3: myapp:some extra data 2420 2421 2422``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2423 Specify SMBIOS type 17 fields 2424ERST 2425 2426DEFHEADING() 2427 2428DEFHEADING(Network options:) 2429 2430DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2431#ifdef CONFIG_SLIRP 2432 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2433 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2434 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2435 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2436 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2437#ifndef _WIN32 2438 "[,smb=dir[,smbserver=addr]]\n" 2439#endif 2440 " configure a user mode network backend with ID 'str',\n" 2441 " its DHCP server and optional services\n" 2442#endif 2443#ifdef _WIN32 2444 "-netdev tap,id=str,ifname=name\n" 2445 " configure a host TAP network backend with ID 'str'\n" 2446#else 2447 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2448 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2449 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2450 " [,poll-us=n]\n" 2451 " configure a host TAP network backend with ID 'str'\n" 2452 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2453 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2454 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2455 " to deconfigure it\n" 2456 " use '[down]script=no' to disable script execution\n" 2457 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2458 " configure it\n" 2459 " use 'fd=h' to connect to an already opened TAP interface\n" 2460 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2461 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2462 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2463 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2464 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2465 " use vhost=on to enable experimental in kernel accelerator\n" 2466 " (only has effect for virtio guests which use MSIX)\n" 2467 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2468 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2469 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2470 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2471 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2472 " spent on busy polling for vhost net\n" 2473 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2474 " configure a host TAP network backend with ID 'str' that is\n" 2475 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2476 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2477#endif 2478#ifdef __linux__ 2479 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2480 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2481 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2482 " [,rxcookie=rxcookie][,offset=offset]\n" 2483 " configure a network backend with ID 'str' connected to\n" 2484 " an Ethernet over L2TPv3 pseudowire.\n" 2485 " Linux kernel 3.3+ as well as most routers can talk\n" 2486 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2487 " VM to a router and even VM to Host. It is a nearly-universal\n" 2488 " standard (RFC3931). Note - this implementation uses static\n" 2489 " pre-configured tunnels (same as the Linux kernel).\n" 2490 " use 'src=' to specify source address\n" 2491 " use 'dst=' to specify destination address\n" 2492 " use 'udp=on' to specify udp encapsulation\n" 2493 " use 'srcport=' to specify source udp port\n" 2494 " use 'dstport=' to specify destination udp port\n" 2495 " use 'ipv6=on' to force v6\n" 2496 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2497 " well as a weak security measure\n" 2498 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2499 " use 'txcookie=0x012345678' to specify a txcookie\n" 2500 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2501 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2502 " use 'pincounter=on' to work around broken counter handling in peer\n" 2503 " use 'offset=X' to add an extra offset between header and data\n" 2504#endif 2505 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2506 " configure a network backend to connect to another network\n" 2507 " using a socket connection\n" 2508 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2509 " configure a network backend to connect to a multicast maddr and port\n" 2510 " use 'localaddr=addr' to specify the host address to send packets from\n" 2511 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2512 " configure a network backend to connect to another network\n" 2513 " using an UDP tunnel\n" 2514#ifdef CONFIG_VDE 2515 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2516 " configure a network backend to connect to port 'n' of a vde switch\n" 2517 " running on host and listening for incoming connections on 'socketpath'.\n" 2518 " Use group 'groupname' and mode 'octalmode' to change default\n" 2519 " ownership and permissions for communication port.\n" 2520#endif 2521#ifdef CONFIG_NETMAP 2522 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2523 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2524 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2525 " netmap device, defaults to '/dev/netmap')\n" 2526#endif 2527#ifdef CONFIG_POSIX 2528 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2529 " configure a vhost-user network, backed by a chardev 'dev'\n" 2530#endif 2531#ifdef __linux__ 2532 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2533 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2534#endif 2535 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2536 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2537DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2538 "-nic [tap|bridge|" 2539#ifdef CONFIG_SLIRP 2540 "user|" 2541#endif 2542#ifdef __linux__ 2543 "l2tpv3|" 2544#endif 2545#ifdef CONFIG_VDE 2546 "vde|" 2547#endif 2548#ifdef CONFIG_NETMAP 2549 "netmap|" 2550#endif 2551#ifdef CONFIG_POSIX 2552 "vhost-user|" 2553#endif 2554 "socket][,option][,...][mac=macaddr]\n" 2555 " initialize an on-board / default host NIC (using MAC address\n" 2556 " macaddr) and connect it to the given host network backend\n" 2557 "-nic none use it alone to have zero network devices (the default is to\n" 2558 " provided a 'user' network connection)\n", 2559 QEMU_ARCH_ALL) 2560DEF("net", HAS_ARG, QEMU_OPTION_net, 2561 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2562 " configure or create an on-board (or machine default) NIC and\n" 2563 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2564 "-net [" 2565#ifdef CONFIG_SLIRP 2566 "user|" 2567#endif 2568 "tap|" 2569 "bridge|" 2570#ifdef CONFIG_VDE 2571 "vde|" 2572#endif 2573#ifdef CONFIG_NETMAP 2574 "netmap|" 2575#endif 2576 "socket][,option][,option][,...]\n" 2577 " old way to initialize a host network interface\n" 2578 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2579SRST 2580``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2581 This option is a shortcut for configuring both the on-board 2582 (default) guest NIC hardware and the host network backend in one go. 2583 The host backend options are the same as with the corresponding 2584 ``-netdev`` options below. The guest NIC model can be set with 2585 ``model=modelname``. Use ``model=help`` to list the available device 2586 types. The hardware MAC address can be set with ``mac=macaddr``. 2587 2588 The following two example do exactly the same, to show how ``-nic`` 2589 can be used to shorten the command line length: 2590 2591 .. parsed-literal:: 2592 2593 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2594 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2595 2596``-nic none`` 2597 Indicate that no network devices should be configured. It is used to 2598 override the default configuration (default NIC with "user" host 2599 network backend) which is activated if no other networking options 2600 are provided. 2601 2602``-netdev user,id=id[,option][,option][,...]`` 2603 Configure user mode host network backend which requires no 2604 administrator privilege to run. Valid options are: 2605 2606 ``id=id`` 2607 Assign symbolic name for use in monitor commands. 2608 2609 ``ipv4=on|off and ipv6=on|off`` 2610 Specify that either IPv4 or IPv6 must be enabled. If neither is 2611 specified both protocols are enabled. 2612 2613 ``net=addr[/mask]`` 2614 Set IP network address the guest will see. Optionally specify 2615 the netmask, either in the form a.b.c.d or as number of valid 2616 top-most bits. Default is 10.0.2.0/24. 2617 2618 ``host=addr`` 2619 Specify the guest-visible address of the host. Default is the 2620 2nd IP in the guest network, i.e. x.x.x.2. 2621 2622 ``ipv6-net=addr[/int]`` 2623 Set IPv6 network address the guest will see (default is 2624 fec0::/64). The network prefix is given in the usual hexadecimal 2625 IPv6 address notation. The prefix size is optional, and is given 2626 as the number of valid top-most bits (default is 64). 2627 2628 ``ipv6-host=addr`` 2629 Specify the guest-visible IPv6 address of the host. Default is 2630 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2631 2632 ``restrict=on|off`` 2633 If this option is enabled, the guest will be isolated, i.e. it 2634 will not be able to contact the host and no guest IP packets 2635 will be routed over the host to the outside. This option does 2636 not affect any explicitly set forwarding rules. 2637 2638 ``hostname=name`` 2639 Specifies the client hostname reported by the built-in DHCP 2640 server. 2641 2642 ``dhcpstart=addr`` 2643 Specify the first of the 16 IPs the built-in DHCP server can 2644 assign. Default is the 15th to 31st IP in the guest network, 2645 i.e. x.x.x.15 to x.x.x.31. 2646 2647 ``dns=addr`` 2648 Specify the guest-visible address of the virtual nameserver. The 2649 address must be different from the host address. Default is the 2650 3rd IP in the guest network, i.e. x.x.x.3. 2651 2652 ``ipv6-dns=addr`` 2653 Specify the guest-visible address of the IPv6 virtual 2654 nameserver. The address must be different from the host address. 2655 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2656 2657 ``dnssearch=domain`` 2658 Provides an entry for the domain-search list sent by the 2659 built-in DHCP server. More than one domain suffix can be 2660 transmitted by specifying this option multiple times. If 2661 supported, this will cause the guest to automatically try to 2662 append the given domain suffix(es) in case a domain name can not 2663 be resolved. 2664 2665 Example: 2666 2667 .. parsed-literal:: 2668 2669 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2670 2671 ``domainname=domain`` 2672 Specifies the client domain name reported by the built-in DHCP 2673 server. 2674 2675 ``tftp=dir`` 2676 When using the user mode network stack, activate a built-in TFTP 2677 server. The files in dir will be exposed as the root of a TFTP 2678 server. The TFTP client on the guest must be configured in 2679 binary mode (use the command ``bin`` of the Unix TFTP client). 2680 2681 ``tftp-server-name=name`` 2682 In BOOTP reply, broadcast name as the "TFTP server name" 2683 (RFC2132 option 66). This can be used to advise the guest to 2684 load boot files or configurations from a different server than 2685 the host address. 2686 2687 ``bootfile=file`` 2688 When using the user mode network stack, broadcast file as the 2689 BOOTP filename. In conjunction with ``tftp``, this can be used 2690 to network boot a guest from a local directory. 2691 2692 Example (using pxelinux): 2693 2694 .. parsed-literal:: 2695 2696 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2697 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2698 2699 ``smb=dir[,smbserver=addr]`` 2700 When using the user mode network stack, activate a built-in SMB 2701 server so that Windows OSes can access to the host files in 2702 ``dir`` transparently. The IP address of the SMB server can be 2703 set to addr. By default the 4th IP in the guest network is used, 2704 i.e. x.x.x.4. 2705 2706 In the guest Windows OS, the line: 2707 2708 :: 2709 2710 10.0.2.4 smbserver 2711 2712 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2713 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2714 NT/2000). 2715 2716 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2717 2718 Note that a SAMBA server must be installed on the host OS. 2719 2720 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2721 Redirect incoming TCP or UDP connections to the host port 2722 hostport to the guest IP address guestaddr on guest port 2723 guestport. If guestaddr is not specified, its value is x.x.x.15 2724 (default first address given by the built-in DHCP server). By 2725 specifying hostaddr, the rule can be bound to a specific host 2726 interface. If no connection type is set, TCP is used. This 2727 option can be given multiple times. 2728 2729 For example, to redirect host X11 connection from screen 1 to 2730 guest screen 0, use the following: 2731 2732 .. parsed-literal:: 2733 2734 # on the host 2735 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2736 # this host xterm should open in the guest X11 server 2737 xterm -display :1 2738 2739 To redirect telnet connections from host port 5555 to telnet 2740 port on the guest, use the following: 2741 2742 .. parsed-literal:: 2743 2744 # on the host 2745 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2746 telnet localhost 5555 2747 2748 Then when you use on the host ``telnet localhost 5555``, you 2749 connect to the guest telnet server. 2750 2751 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2752 Forward guest TCP connections to the IP address server on port 2753 port to the character device dev or to a program executed by 2754 cmd:command which gets spawned for each connection. This option 2755 can be given multiple times. 2756 2757 You can either use a chardev directly and have that one used 2758 throughout QEMU's lifetime, like in the following example: 2759 2760 .. parsed-literal:: 2761 2762 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2763 # the guest accesses it 2764 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2765 2766 Or you can execute a command on every TCP connection established 2767 by the guest, so that QEMU behaves similar to an inetd process 2768 for that virtual server: 2769 2770 .. parsed-literal:: 2771 2772 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2773 # and connect the TCP stream to its stdin/stdout 2774 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2775 2776``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2777 Configure a host TAP network backend with ID id. 2778 2779 Use the network script file to configure it and the network script 2780 dfile to deconfigure it. If name is not provided, the OS 2781 automatically provides one. The default network configure script is 2782 ``/etc/qemu-ifup`` and the default network deconfigure script is 2783 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2784 disable script execution. 2785 2786 If running QEMU as an unprivileged user, use the network helper 2787 to configure the TAP interface and attach it to the bridge. 2788 The default network helper executable is 2789 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2790 ``br0``. 2791 2792 ``fd``\ =h can be used to specify the handle of an already opened 2793 host TAP interface. 2794 2795 Examples: 2796 2797 .. parsed-literal:: 2798 2799 #launch a QEMU instance with the default network script 2800 |qemu_system| linux.img -nic tap 2801 2802 .. parsed-literal:: 2803 2804 #launch a QEMU instance with two NICs, each one connected 2805 #to a TAP device 2806 |qemu_system| linux.img \\ 2807 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2808 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2809 2810 .. parsed-literal:: 2811 2812 #launch a QEMU instance with the default network helper to 2813 #connect a TAP device to bridge br0 2814 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2815 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2816 2817``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2818 Connect a host TAP network interface to a host bridge device. 2819 2820 Use the network helper helper to configure the TAP interface and 2821 attach it to the bridge. The default network helper executable is 2822 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2823 ``br0``. 2824 2825 Examples: 2826 2827 .. parsed-literal:: 2828 2829 #launch a QEMU instance with the default network helper to 2830 #connect a TAP device to bridge br0 2831 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2832 2833 .. parsed-literal:: 2834 2835 #launch a QEMU instance with the default network helper to 2836 #connect a TAP device to bridge qemubr0 2837 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2838 2839``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2840 This host network backend can be used to connect the guest's network 2841 to another QEMU virtual machine using a TCP socket connection. If 2842 ``listen`` is specified, QEMU waits for incoming connections on port 2843 (host is optional). ``connect`` is used to connect to another QEMU 2844 instance using the ``listen`` option. ``fd``\ =h specifies an 2845 already opened TCP socket. 2846 2847 Example: 2848 2849 .. parsed-literal:: 2850 2851 # launch a first QEMU instance 2852 |qemu_system| linux.img \\ 2853 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2854 -netdev socket,id=n1,listen=:1234 2855 # connect the network of this instance to the network of the first instance 2856 |qemu_system| linux.img \\ 2857 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2858 -netdev socket,id=n2,connect=127.0.0.1:1234 2859 2860``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2861 Configure a socket host network backend to share the guest's network 2862 traffic with another QEMU virtual machines using a UDP multicast 2863 socket, effectively making a bus for every QEMU with same multicast 2864 address maddr and port. NOTES: 2865 2866 1. Several QEMU can be running on different hosts and share same bus 2867 (assuming correct multicast setup for these hosts). 2868 2869 2. mcast support is compatible with User Mode Linux (argument 2870 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2871 2872 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2873 2874 Example: 2875 2876 .. parsed-literal:: 2877 2878 # launch one QEMU instance 2879 |qemu_system| linux.img \\ 2880 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2881 -netdev socket,id=n1,mcast=230.0.0.1:1234 2882 # launch another QEMU instance on same "bus" 2883 |qemu_system| linux.img \\ 2884 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2885 -netdev socket,id=n2,mcast=230.0.0.1:1234 2886 # launch yet another QEMU instance on same "bus" 2887 |qemu_system| linux.img \\ 2888 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2889 -netdev socket,id=n3,mcast=230.0.0.1:1234 2890 2891 Example (User Mode Linux compat.): 2892 2893 .. parsed-literal:: 2894 2895 # launch QEMU instance (note mcast address selected is UML's default) 2896 |qemu_system| linux.img \\ 2897 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2898 -netdev socket,id=n1,mcast=239.192.168.1:1102 2899 # launch UML 2900 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2901 2902 Example (send packets from host's 1.2.3.4): 2903 2904 .. parsed-literal:: 2905 2906 |qemu_system| linux.img \\ 2907 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2908 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2909 2910``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2911 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2912 is a popular protocol to transport Ethernet (and other Layer 2) data 2913 frames between two systems. It is present in routers, firewalls and 2914 the Linux kernel (from version 3.3 onwards). 2915 2916 This transport allows a VM to communicate to another VM, router or 2917 firewall directly. 2918 2919 ``src=srcaddr`` 2920 source address (mandatory) 2921 2922 ``dst=dstaddr`` 2923 destination address (mandatory) 2924 2925 ``udp`` 2926 select udp encapsulation (default is ip). 2927 2928 ``srcport=srcport`` 2929 source udp port. 2930 2931 ``dstport=dstport`` 2932 destination udp port. 2933 2934 ``ipv6`` 2935 force v6, otherwise defaults to v4. 2936 2937 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2938 Cookies are a weak form of security in the l2tpv3 specification. 2939 Their function is mostly to prevent misconfiguration. By default 2940 they are 32 bit. 2941 2942 ``cookie64`` 2943 Set cookie size to 64 bit instead of the default 32 2944 2945 ``counter=off`` 2946 Force a 'cut-down' L2TPv3 with no counter as in 2947 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2948 2949 ``pincounter=on`` 2950 Work around broken counter handling in peer. This may also help 2951 on networks which have packet reorder. 2952 2953 ``offset=offset`` 2954 Add an extra offset between header and data 2955 2956 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 2957 the bridge br-lan on the remote Linux host 1.2.3.4: 2958 2959 .. parsed-literal:: 2960 2961 # Setup tunnel on linux host using raw ip as encapsulation 2962 # on 1.2.3.4 2963 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 2964 encap udp udp_sport 16384 udp_dport 16384 2965 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 2966 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2967 ifconfig vmtunnel0 mtu 1500 2968 ifconfig vmtunnel0 up 2969 brctl addif br-lan vmtunnel0 2970 2971 2972 # on 4.3.2.1 2973 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2974 2975 |qemu_system| linux.img -device e1000,netdev=n1 \\ 2976 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2977 2978``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 2979 Configure VDE backend to connect to PORT n of a vde switch running 2980 on host and listening for incoming connections on socketpath. Use 2981 GROUP groupname and MODE octalmode to change default ownership and 2982 permissions for communication port. This option is only available if 2983 QEMU has been compiled with vde support enabled. 2984 2985 Example: 2986 2987 .. parsed-literal:: 2988 2989 # launch vde switch 2990 vde_switch -F -sock /tmp/myswitch 2991 # launch QEMU instance 2992 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 2993 2994``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 2995 Establish a vhost-user netdev, backed by a chardev id. The chardev 2996 should be a unix domain socket backed one. The vhost-user uses a 2997 specifically defined protocol to pass vhost ioctl replacement 2998 messages to an application on the other end of the socket. On 2999 non-MSIX guests, the feature can be forced with vhostforce. Use 3000 'queues=n' to specify the number of queues to be created for 3001 multiqueue vhost-user. 3002 3003 Example: 3004 3005 :: 3006 3007 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3008 -numa node,memdev=mem \ 3009 -chardev socket,id=chr0,path=/path/to/socket \ 3010 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3011 -device virtio-net-pci,netdev=net0 3012 3013``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3014 Establish a vhost-vdpa netdev. 3015 3016 vDPA device is a device that uses a datapath which complies with 3017 the virtio specifications with a vendor specific control path. 3018 vDPA devices can be both physically located on the hardware or 3019 emulated by software. 3020 3021``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3022 Create a hub port on the emulated hub with ID hubid. 3023 3024 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3025 instead of a single netdev. Alternatively, you can also connect the 3026 hubport to another netdev with ID nd by using the ``netdev=nd`` 3027 option. 3028 3029``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3030 Legacy option to configure or create an on-board (or machine 3031 default) Network Interface Card(NIC) and connect it either to the 3032 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3033 If model is omitted, then the default NIC model associated with the 3034 machine type is used. Note that the default NIC model may change in 3035 future QEMU releases, so it is highly recommended to always specify 3036 a model. Optionally, the MAC address can be changed to mac, the 3037 device address set to addr (PCI cards only), and a name can be 3038 assigned for use in monitor commands. Optionally, for PCI cards, you 3039 can specify the number v of MSI-X vectors that the card should have; 3040 this option currently only affects virtio cards; set v = 0 to 3041 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3042 created. QEMU can emulate several different models of network card. 3043 Use ``-net nic,model=help`` for a list of available devices for your 3044 target. 3045 3046``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3047 Configure a host network backend (with the options corresponding to 3048 the same ``-netdev`` option) and connect it to the emulated hub 0 3049 (the default hub). Use name to specify the name of the hub port. 3050ERST 3051 3052DEFHEADING() 3053 3054DEFHEADING(Character device options:) 3055 3056DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3057 "-chardev help\n" 3058 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3059 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3060 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3061 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3062 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3063 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3064 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3065 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3066 " [,logfile=PATH][,logappend=on|off]\n" 3067 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3068 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3069 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3070 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3071 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3072 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3073#ifdef _WIN32 3074 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3075 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3076#else 3077 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3078 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3079#endif 3080#ifdef CONFIG_BRLAPI 3081 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3082#endif 3083#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3084 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3085 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3086 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3087#endif 3088#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3089 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3090 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3091#endif 3092#if defined(CONFIG_SPICE) 3093 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3094 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3095#endif 3096 , QEMU_ARCH_ALL 3097) 3098 3099SRST 3100The general form of a character device option is: 3101 3102``-chardev backend,id=id[,mux=on|off][,options]`` 3103 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3104 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3105 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3106 ``spicevmc``, ``spiceport``. The specific backend will determine the 3107 applicable options. 3108 3109 Use ``-chardev help`` to print all available chardev backend types. 3110 3111 All devices must have an id, which can be any string up to 127 3112 characters long. It is used to uniquely identify this device in 3113 other command line directives. 3114 3115 A character device may be used in multiplexing mode by multiple 3116 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3117 a "1:N" device, and here the "1" end is your specified chardev 3118 backend, and the "N" end is the various parts of QEMU that can talk 3119 to a chardev. If you create a chardev with ``id=myid`` and 3120 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3121 and you can then configure multiple front ends to use that chardev 3122 ID for their input/output. Up to four different front ends can be 3123 connected to a single multiplexed chardev. (Without multiplexing 3124 enabled, a chardev can only be used by a single front end.) For 3125 instance you could use this to allow a single stdio chardev to be 3126 used by two serial ports and the QEMU monitor: 3127 3128 :: 3129 3130 -chardev stdio,mux=on,id=char0 \ 3131 -mon chardev=char0,mode=readline \ 3132 -serial chardev:char0 \ 3133 -serial chardev:char0 3134 3135 You can have more than one multiplexer in a system configuration; 3136 for instance you could have a TCP port multiplexed between UART 0 3137 and UART 1, and stdio multiplexed between the QEMU monitor and a 3138 parallel port: 3139 3140 :: 3141 3142 -chardev stdio,mux=on,id=char0 \ 3143 -mon chardev=char0,mode=readline \ 3144 -parallel chardev:char0 \ 3145 -chardev tcp,...,mux=on,id=char1 \ 3146 -serial chardev:char1 \ 3147 -serial chardev:char1 3148 3149 When you're using a multiplexed character device, some escape 3150 sequences are interpreted in the input. See the chapter about 3151 :ref:`keys in the character backend multiplexer` in the 3152 System Emulation Users Guide for more details. 3153 3154 Note that some other command line options may implicitly create 3155 multiplexed character backends; for instance ``-serial mon:stdio`` 3156 creates a multiplexed stdio backend connected to the serial port and 3157 the QEMU monitor, and ``-nographic`` also multiplexes the console 3158 and the monitor to stdio. 3159 3160 There is currently no support for multiplexing in the other 3161 direction (where a single QEMU front end takes input and output from 3162 multiple chardevs). 3163 3164 Every backend supports the ``logfile`` option, which supplies the 3165 path to a file to record all data transmitted via the backend. The 3166 ``logappend`` option controls whether the log file will be truncated 3167 or appended to when opened. 3168 3169The available backends are: 3170 3171``-chardev null,id=id`` 3172 A void device. This device will not emit any data, and will drop any 3173 data it receives. The null backend does not take any options. 3174 3175``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3176 Create a two-way stream socket, which can be either a TCP or a unix 3177 socket. A unix socket will be created if ``path`` is specified. 3178 Behaviour is undefined if TCP options are specified for a unix 3179 socket. 3180 3181 ``server=on|off`` specifies that the socket shall be a listening socket. 3182 3183 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3184 to connect to a listening socket. 3185 3186 ``telnet=on|off`` specifies that traffic on the socket should interpret 3187 telnet escape sequences. 3188 3189 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3190 communication. 3191 3192 ``reconnect`` sets the timeout for reconnecting on non-server 3193 sockets when the remote end goes away. qemu will delay this many 3194 seconds and then attempt to reconnect. Zero disables reconnecting, 3195 and is the default. 3196 3197 ``tls-creds`` requests enablement of the TLS protocol for 3198 encryption, and specifies the id of the TLS credentials to use for 3199 the handshake. The credentials must be previously created with the 3200 ``-object tls-creds`` argument. 3201 3202 ``tls-auth`` provides the ID of the QAuthZ authorization object 3203 against which the client's x509 distinguished name will be 3204 validated. This object is only resolved at time of use, so can be 3205 deleted and recreated on the fly while the chardev server is active. 3206 If missing, it will default to denying access. 3207 3208 TCP and unix socket options are given below: 3209 3210 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3211 ``host`` for a listening socket specifies the local address to 3212 be bound. For a connecting socket species the remote host to 3213 connect to. ``host`` is optional for listening sockets. If not 3214 specified it defaults to ``0.0.0.0``. 3215 3216 ``port`` for a listening socket specifies the local port to be 3217 bound. For a connecting socket specifies the port on the remote 3218 host to connect to. ``port`` can be given as either a port 3219 number or a service name. ``port`` is required. 3220 3221 ``to`` is only relevant to listening sockets. If it is 3222 specified, and ``port`` cannot be bound, QEMU will attempt to 3223 bind to subsequent ports up to and including ``to`` until it 3224 succeeds. ``to`` must be specified as a port number. 3225 3226 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3227 or IPv6 must be used. If neither is specified the socket may 3228 use either protocol. 3229 3230 ``nodelay=on|off`` disables the Nagle algorithm. 3231 3232 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3233 ``path`` specifies the local path of the unix socket. ``path`` 3234 is required. 3235 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3236 rather than the filesystem. Optional, defaults to false. 3237 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3238 rather than the full sun_path length. Optional, defaults to true. 3239 3240``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3241 Sends all traffic from the guest to a remote host over UDP. 3242 3243 ``host`` specifies the remote host to connect to. If not specified 3244 it defaults to ``localhost``. 3245 3246 ``port`` specifies the port on the remote host to connect to. 3247 ``port`` is required. 3248 3249 ``localaddr`` specifies the local address to bind to. If not 3250 specified it defaults to ``0.0.0.0``. 3251 3252 ``localport`` specifies the local port to bind to. If not specified 3253 any available local port will be used. 3254 3255 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3256 If neither is specified the device may use either protocol. 3257 3258``-chardev msmouse,id=id`` 3259 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3260 does not take any options. 3261 3262``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3263 Connect to a QEMU text console. ``vc`` may optionally be given a 3264 specific size. 3265 3266 ``width`` and ``height`` specify the width and height respectively 3267 of the console, in pixels. 3268 3269 ``cols`` and ``rows`` specify that the console be sized to fit a 3270 text console with the given dimensions. 3271 3272``-chardev ringbuf,id=id[,size=size]`` 3273 Create a ring buffer with fixed size ``size``. size must be a power 3274 of two and defaults to ``64K``. 3275 3276``-chardev file,id=id,path=path`` 3277 Log all traffic received from the guest to a file. 3278 3279 ``path`` specifies the path of the file to be opened. This file will 3280 be created if it does not already exist, and overwritten if it does. 3281 ``path`` is required. 3282 3283``-chardev pipe,id=id,path=path`` 3284 Create a two-way connection to the guest. The behaviour differs 3285 slightly between Windows hosts and other hosts: 3286 3287 On Windows, a single duplex pipe will be created at 3288 ``\\.pipe\path``. 3289 3290 On other hosts, 2 pipes will be created called ``path.in`` and 3291 ``path.out``. Data written to ``path.in`` will be received by the 3292 guest. Data written by the guest can be read from ``path.out``. QEMU 3293 will not create these fifos, and requires them to be present. 3294 3295 ``path`` forms part of the pipe path as described above. ``path`` is 3296 required. 3297 3298``-chardev console,id=id`` 3299 Send traffic from the guest to QEMU's standard output. ``console`` 3300 does not take any options. 3301 3302 ``console`` is only available on Windows hosts. 3303 3304``-chardev serial,id=id,path=path`` 3305 Send traffic from the guest to a serial device on the host. 3306 3307 On Unix hosts serial will actually accept any tty device, not only 3308 serial lines. 3309 3310 ``path`` specifies the name of the serial device to open. 3311 3312``-chardev pty,id=id`` 3313 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3314 does not take any options. 3315 3316 ``pty`` is not available on Windows hosts. 3317 3318``-chardev stdio,id=id[,signal=on|off]`` 3319 Connect to standard input and standard output of the QEMU process. 3320 3321 ``signal`` controls if signals are enabled on the terminal, that 3322 includes exiting QEMU with the key sequence Control-c. This option 3323 is enabled by default, use ``signal=off`` to disable it. 3324 3325``-chardev braille,id=id`` 3326 Connect to a local BrlAPI server. ``braille`` does not take any 3327 options. 3328 3329``-chardev tty,id=id,path=path`` 3330 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3331 and DragonFlyBSD hosts. It is an alias for ``serial``. 3332 3333 ``path`` specifies the path to the tty. ``path`` is required. 3334 3335``-chardev parallel,id=id,path=path`` 3336 \ 3337``-chardev parport,id=id,path=path`` 3338 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3339 hosts. 3340 3341 Connect to a local parallel port. 3342 3343 ``path`` specifies the path to the parallel port device. ``path`` is 3344 required. 3345 3346``-chardev spicevmc,id=id,debug=debug,name=name`` 3347 ``spicevmc`` is only available when spice support is built in. 3348 3349 ``debug`` debug level for spicevmc 3350 3351 ``name`` name of spice channel to connect to 3352 3353 Connect to a spice virtual machine channel, such as vdiport. 3354 3355``-chardev spiceport,id=id,debug=debug,name=name`` 3356 ``spiceport`` is only available when spice support is built in. 3357 3358 ``debug`` debug level for spicevmc 3359 3360 ``name`` name of spice port to connect to 3361 3362 Connect to a spice port, allowing a Spice client to handle the 3363 traffic identified by a name (preferably a fqdn). 3364ERST 3365 3366DEFHEADING() 3367 3368#ifdef CONFIG_TPM 3369DEFHEADING(TPM device options:) 3370 3371DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3372 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3373 " use path to provide path to a character device; default is /dev/tpm0\n" 3374 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3375 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3376 "-tpmdev emulator,id=id,chardev=dev\n" 3377 " configure the TPM device using chardev backend\n", 3378 QEMU_ARCH_ALL) 3379SRST 3380The general form of a TPM device option is: 3381 3382``-tpmdev backend,id=id[,options]`` 3383 The specific backend type will determine the applicable options. The 3384 ``-tpmdev`` option creates the TPM backend and requires a 3385 ``-device`` option that specifies the TPM frontend interface model. 3386 3387 Use ``-tpmdev help`` to print all available TPM backend types. 3388 3389The available backends are: 3390 3391``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3392 (Linux-host only) Enable access to the host's TPM using the 3393 passthrough driver. 3394 3395 ``path`` specifies the path to the host's TPM device, i.e., on a 3396 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3397 default ``/dev/tpm0`` is used. 3398 3399 ``cancel-path`` specifies the path to the host TPM device's sysfs 3400 entry allowing for cancellation of an ongoing TPM command. 3401 ``cancel-path`` is optional and by default QEMU will search for the 3402 sysfs entry to use. 3403 3404 Some notes about using the host's TPM with the passthrough driver: 3405 3406 The TPM device accessed by the passthrough driver must not be used 3407 by any other application on the host. 3408 3409 Since the host's firmware (BIOS/UEFI) has already initialized the 3410 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3411 the TPM again and may therefore not show a TPM-specific menu that 3412 would otherwise allow the user to configure the TPM, e.g., allow the 3413 user to enable/disable or activate/deactivate the TPM. Further, if 3414 TPM ownership is released from within a VM then the host's TPM will 3415 get disabled and deactivated. To enable and activate the TPM again 3416 afterwards, the host has to be rebooted and the user is required to 3417 enter the firmware's menu to enable and activate the TPM. If the TPM 3418 is left disabled and/or deactivated most TPM commands will fail. 3419 3420 To create a passthrough TPM use the following two options: 3421 3422 :: 3423 3424 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3425 3426 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3427 ``tpmdev=tpm0`` in the device option. 3428 3429``-tpmdev emulator,id=id,chardev=dev`` 3430 (Linux-host only) Enable access to a TPM emulator using Unix domain 3431 socket based chardev backend. 3432 3433 ``chardev`` specifies the unique ID of a character device backend 3434 that provides connection to the software TPM server. 3435 3436 To create a TPM emulator backend device with chardev socket backend: 3437 3438 :: 3439 3440 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3441ERST 3442 3443DEFHEADING() 3444 3445#endif 3446 3447DEFHEADING(Linux/Multiboot boot specific:) 3448SRST 3449When using these options, you can use a given Linux or Multiboot kernel 3450without installing it in the disk image. It can be useful for easier 3451testing of various kernels. 3452 3453 3454ERST 3455 3456DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3457 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3458SRST 3459``-kernel bzImage`` 3460 Use bzImage as kernel image. The kernel can be either a Linux kernel 3461 or in multiboot format. 3462ERST 3463 3464DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3465 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3466SRST 3467``-append cmdline`` 3468 Use cmdline as kernel command line 3469ERST 3470 3471DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3472 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3473SRST 3474``-initrd file`` 3475 Use file as initial ram disk. 3476 3477``-initrd "file1 arg=foo,file2"`` 3478 This syntax is only available with multiboot. 3479 3480 Use file1 and file2 as modules and pass arg=foo as parameter to the 3481 first module. 3482ERST 3483 3484DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3485 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3486SRST 3487``-dtb file`` 3488 Use file as a device tree binary (dtb) image and pass it to the 3489 kernel on boot. 3490ERST 3491 3492DEFHEADING() 3493 3494DEFHEADING(Debug/Expert options:) 3495 3496DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3497 "-fw_cfg [name=]<name>,file=<file>\n" 3498 " add named fw_cfg entry with contents from file\n" 3499 "-fw_cfg [name=]<name>,string=<str>\n" 3500 " add named fw_cfg entry with contents from string\n", 3501 QEMU_ARCH_ALL) 3502SRST 3503``-fw_cfg [name=]name,file=file`` 3504 Add named fw\_cfg entry with contents from file file. 3505 3506``-fw_cfg [name=]name,string=str`` 3507 Add named fw\_cfg entry with contents from string str. 3508 3509 The terminating NUL character of the contents of str will not be 3510 included as part of the fw\_cfg item data. To insert contents with 3511 embedded NUL characters, you have to use the file parameter. 3512 3513 The fw\_cfg entries are passed by QEMU through to the guest. 3514 3515 Example: 3516 3517 :: 3518 3519 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3520 3521 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3522 from ./my\_blob.bin. 3523ERST 3524 3525DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3526 "-serial dev redirect the serial port to char device 'dev'\n", 3527 QEMU_ARCH_ALL) 3528SRST 3529``-serial dev`` 3530 Redirect the virtual serial port to host character device dev. The 3531 default device is ``vc`` in graphical mode and ``stdio`` in non 3532 graphical mode. 3533 3534 This option can be used several times to simulate up to 4 serial 3535 ports. 3536 3537 Use ``-serial none`` to disable all serial ports. 3538 3539 Available character devices are: 3540 3541 ``vc[:WxH]`` 3542 Virtual console. Optionally, a width and height can be given in 3543 pixel with 3544 3545 :: 3546 3547 vc:800x600 3548 3549 It is also possible to specify width or height in characters: 3550 3551 :: 3552 3553 vc:80Cx24C 3554 3555 ``pty`` 3556 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3557 3558 ``none`` 3559 No device is allocated. 3560 3561 ``null`` 3562 void device 3563 3564 ``chardev:id`` 3565 Use a named character device defined with the ``-chardev`` 3566 option. 3567 3568 ``/dev/XXX`` 3569 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3570 port parameters are set according to the emulated ones. 3571 3572 ``/dev/parportN`` 3573 [Linux only, parallel port only] Use host parallel port N. 3574 Currently SPP and EPP parallel port features can be used. 3575 3576 ``file:filename`` 3577 Write output to filename. No character can be read. 3578 3579 ``stdio`` 3580 [Unix only] standard input/output 3581 3582 ``pipe:filename`` 3583 name pipe filename 3584 3585 ``COMn`` 3586 [Windows only] Use host serial port n 3587 3588 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3589 This implements UDP Net Console. When remote\_host or src\_ip 3590 are not specified they default to ``0.0.0.0``. When not using a 3591 specified src\_port a random port is automatically chosen. 3592 3593 If you just want a simple readonly console you can use 3594 ``netcat`` or ``nc``, by starting QEMU with: 3595 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3596 QEMU writes something to that port it will appear in the 3597 netconsole session. 3598 3599 If you plan to send characters back via netconsole or you want 3600 to stop and start QEMU a lot of times, you should have QEMU use 3601 the same source port each time by using something like ``-serial 3602 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3603 version of netcat which can listen to a TCP port and send and 3604 receive characters via udp. If you have a patched version of 3605 netcat which activates telnet remote echo and single char 3606 transfer, then you can use the following options to set up a 3607 netcat redirector to allow telnet on port 5555 to access the 3608 QEMU port. 3609 3610 ``QEMU Options:`` 3611 -serial udp::4555@:4556 3612 3613 ``netcat options:`` 3614 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3615 3616 ``telnet options:`` 3617 localhost 5555 3618 3619 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3620 The TCP Net Console has two modes of operation. It can send the 3621 serial I/O to a location or wait for a connection from a 3622 location. By default the TCP Net Console is sent to host at the 3623 port. If you use the ``server=on`` option QEMU will wait for a client 3624 socket application to connect to the port before continuing, 3625 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3626 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3627 option only applies if ``server=no`` is set, if the connection goes 3628 down it will attempt to reconnect at the given interval. If host 3629 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3630 time is accepted. You can use ``telnet=on`` to connect to the 3631 corresponding character device. 3632 3633 ``Example to send tcp console to 192.168.0.2 port 4444`` 3634 -serial tcp:192.168.0.2:4444 3635 3636 ``Example to listen and wait on port 4444 for connection`` 3637 -serial tcp::4444,server=on 3638 3639 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3640 -serial tcp:192.168.0.100:4444,server=on,wait=off 3641 3642 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3643 The telnet protocol is used instead of raw tcp sockets. The 3644 options work the same as if you had specified ``-serial tcp``. 3645 The difference is that the port acts like a telnet server or 3646 client using telnet option negotiation. This will also allow you 3647 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3648 supports sending the break sequence. Typically in unix telnet 3649 you do it with Control-] and then type "send break" followed by 3650 pressing the enter key. 3651 3652 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3653 The WebSocket protocol is used instead of raw tcp socket. The 3654 port acts as a WebSocket server. Client mode is not supported. 3655 3656 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3657 A unix domain socket is used instead of a tcp socket. The option 3658 works the same as if you had specified ``-serial tcp`` except 3659 the unix domain socket path is used for connections. 3660 3661 ``mon:dev_string`` 3662 This is a special option to allow the monitor to be multiplexed 3663 onto another serial port. The monitor is accessed with key 3664 sequence of Control-a and then pressing c. dev\_string should be 3665 any one of the serial devices specified above. An example to 3666 multiplex the monitor onto a telnet server listening on port 3667 4444 would be: 3668 3669 ``-serial mon:telnet::4444,server=on,wait=off`` 3670 3671 When the monitor is multiplexed to stdio in this way, Ctrl+C 3672 will not terminate QEMU any more but will be passed to the guest 3673 instead. 3674 3675 ``braille`` 3676 Braille device. This will use BrlAPI to display the braille 3677 output on a real or fake device. 3678 3679 ``msmouse`` 3680 Three button serial mouse. Configure the guest to use Microsoft 3681 protocol. 3682ERST 3683 3684DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3685 "-parallel dev redirect the parallel port to char device 'dev'\n", 3686 QEMU_ARCH_ALL) 3687SRST 3688``-parallel dev`` 3689 Redirect the virtual parallel port to host device dev (same devices 3690 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3691 to use hardware devices connected on the corresponding host parallel 3692 port. 3693 3694 This option can be used several times to simulate up to 3 parallel 3695 ports. 3696 3697 Use ``-parallel none`` to disable all parallel ports. 3698ERST 3699 3700DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3701 "-monitor dev redirect the monitor to char device 'dev'\n", 3702 QEMU_ARCH_ALL) 3703SRST 3704``-monitor dev`` 3705 Redirect the monitor to host device dev (same devices as the serial 3706 port). The default device is ``vc`` in graphical mode and ``stdio`` 3707 in non graphical mode. Use ``-monitor none`` to disable the default 3708 monitor. 3709ERST 3710DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3711 "-qmp dev like -monitor but opens in 'control' mode\n", 3712 QEMU_ARCH_ALL) 3713SRST 3714``-qmp dev`` 3715 Like -monitor but opens in 'control' mode. 3716ERST 3717DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3718 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3719 QEMU_ARCH_ALL) 3720SRST 3721``-qmp-pretty dev`` 3722 Like -qmp but uses pretty JSON formatting. 3723ERST 3724 3725DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3726 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3727SRST 3728``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3729 Setup monitor on chardev name. ``pretty`` turns on JSON pretty 3730 printing easing human reading and debugging. 3731ERST 3732 3733DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3734 "-debugcon dev redirect the debug console to char device 'dev'\n", 3735 QEMU_ARCH_ALL) 3736SRST 3737``-debugcon dev`` 3738 Redirect the debug console to host device dev (same devices as the 3739 serial port). The debug console is an I/O port which is typically 3740 port 0xe9; writing to that I/O port sends output to this device. The 3741 default device is ``vc`` in graphical mode and ``stdio`` in non 3742 graphical mode. 3743ERST 3744 3745DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3746 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3747SRST 3748``-pidfile file`` 3749 Store the QEMU process PID in file. It is useful if you launch QEMU 3750 from a script. 3751ERST 3752 3753DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3754 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3755SRST 3756``-singlestep`` 3757 Run the emulation in single step mode. 3758ERST 3759 3760DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3761 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3762 QEMU_ARCH_ALL) 3763SRST 3764``--preconfig`` 3765 Pause QEMU for interactive configuration before the machine is 3766 created, which allows querying and configuring properties that will 3767 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3768 exit the preconfig state and move to the next state (i.e. run guest 3769 if -S isn't used or pause the second time if -S is used). This 3770 option is experimental. 3771ERST 3772 3773DEF("S", 0, QEMU_OPTION_S, \ 3774 "-S freeze CPU at startup (use 'c' to start execution)\n", 3775 QEMU_ARCH_ALL) 3776SRST 3777``-S`` 3778 Do not start CPU at startup (you must type 'c' in the monitor). 3779ERST 3780 3781DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3782 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3783 " run qemu with overcommit hints\n" 3784 " mem-lock=on|off controls memory lock support (default: off)\n" 3785 " cpu-pm=on|off controls cpu power management (default: off)\n", 3786 QEMU_ARCH_ALL) 3787SRST 3788``-overcommit mem-lock=on|off`` 3789 \ 3790``-overcommit cpu-pm=on|off`` 3791 Run qemu with hints about host resource overcommit. The default is 3792 to assume that host overcommits all resources. 3793 3794 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3795 (disabled by default). This works when host memory is not 3796 overcommitted and reduces the worst-case latency for guest. 3797 3798 Guest ability to manage power state of host cpus (increasing latency 3799 for other processes on the same host cpu, but decreasing latency for 3800 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3801 works best when host CPU is not overcommitted. When used, host 3802 estimates of CPU cycle and power utilization will be incorrect, not 3803 taking into account guest idle time. 3804ERST 3805 3806DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3807 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3808 " the guest without waiting for gdb to connect; use -S too\n" 3809 " if you want it to not start execution.)\n", 3810 QEMU_ARCH_ALL) 3811SRST 3812``-gdb dev`` 3813 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3814 in the System Emulation Users Guide). Note that this option does not pause QEMU 3815 execution -- if you want QEMU to not start the guest until you 3816 connect with gdb and issue a ``continue`` command, you will need to 3817 also pass the ``-S`` option to QEMU. 3818 3819 The most usual configuration is to listen on a local TCP socket:: 3820 3821 -gdb tcp::3117 3822 3823 but you can specify other backends; UDP, pseudo TTY, or even stdio 3824 are all reasonable use cases. For example, a stdio connection 3825 allows you to start QEMU from within gdb and establish the 3826 connection via a pipe: 3827 3828 .. parsed-literal:: 3829 3830 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3831ERST 3832 3833DEF("s", 0, QEMU_OPTION_s, \ 3834 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3835 QEMU_ARCH_ALL) 3836SRST 3837``-s`` 3838 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3839 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3840ERST 3841 3842DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3843 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3844 QEMU_ARCH_ALL) 3845SRST 3846``-d item1[,...]`` 3847 Enable logging of specified items. Use '-d help' for a list of log 3848 items. 3849ERST 3850 3851DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3852 "-D logfile output log to logfile (default stderr)\n", 3853 QEMU_ARCH_ALL) 3854SRST 3855``-D logfile`` 3856 Output log in logfile instead of to stderr 3857ERST 3858 3859DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3860 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3861 QEMU_ARCH_ALL) 3862SRST 3863``-dfilter range1[,...]`` 3864 Filter debug output to that relevant to a range of target addresses. 3865 The filter spec can be either start+size, start-size or start..end 3866 where start end and size are the addresses and sizes required. For 3867 example: 3868 3869 :: 3870 3871 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3872 3873 Will dump output for any code in the 0x1000 sized block starting at 3874 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3875 another 0x1000 sized block starting at 0xffffffc00005f000. 3876ERST 3877 3878DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3879 "-seed number seed the pseudo-random number generator\n", 3880 QEMU_ARCH_ALL) 3881SRST 3882``-seed number`` 3883 Force the guest to use a deterministic pseudo-random number 3884 generator, seeded with number. This does not affect crypto routines 3885 within the host. 3886ERST 3887 3888DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3889 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3890 QEMU_ARCH_ALL) 3891SRST 3892``-L path`` 3893 Set the directory for the BIOS, VGA BIOS and keymaps. 3894 3895 To list all the data directories, use ``-L help``. 3896ERST 3897 3898DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3899 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3900SRST 3901``-bios file`` 3902 Set the filename for the BIOS. 3903ERST 3904 3905DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3906 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3907SRST 3908``-enable-kvm`` 3909 Enable KVM full virtualization support. This option is only 3910 available if KVM support is enabled when compiling. 3911ERST 3912 3913DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3914 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3915DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3916 "-xen-attach attach to existing xen domain\n" 3917 " libxl will use this when starting QEMU\n", 3918 QEMU_ARCH_ALL) 3919DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3920 "-xen-domid-restrict restrict set of available xen operations\n" 3921 " to specified domain id. (Does not affect\n" 3922 " xenpv machine type).\n", 3923 QEMU_ARCH_ALL) 3924SRST 3925``-xen-domid id`` 3926 Specify xen guest domain id (XEN only). 3927 3928``-xen-attach`` 3929 Attach to existing xen domain. libxl will use this when starting 3930 QEMU (XEN only). Restrict set of available xen operations to 3931 specified domain id (XEN only). 3932ERST 3933 3934DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3935 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3936SRST 3937``-no-reboot`` 3938 Exit instead of rebooting. 3939ERST 3940 3941DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3942 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3943SRST 3944``-no-shutdown`` 3945 Don't exit QEMU on guest shutdown, but instead only stop the 3946 emulation. This allows for instance switching to monitor to commit 3947 changes to the disk image. 3948ERST 3949 3950DEF("action", HAS_ARG, QEMU_OPTION_action, 3951 "-action reboot=reset|shutdown\n" 3952 " action when guest reboots [default=reset]\n" 3953 "-action shutdown=poweroff|pause\n" 3954 " action when guest shuts down [default=poweroff]\n" 3955 "-action panic=pause|shutdown|none\n" 3956 " action when guest panics [default=shutdown]\n" 3957 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 3958 " action when watchdog fires [default=reset]\n", 3959 QEMU_ARCH_ALL) 3960SRST 3961``-action event=action`` 3962 The action parameter serves to modify QEMU's default behavior when 3963 certain guest events occur. It provides a generic method for specifying the 3964 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 3965 parameters. 3966 3967 Examples: 3968 3969 ``-action panic=none`` 3970 ``-action reboot=shutdown,shutdown=pause`` 3971 ``-watchdog i6300esb -action watchdog=pause`` 3972 3973ERST 3974 3975DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3976 "-loadvm [tag|id]\n" \ 3977 " start right away with a saved state (loadvm in monitor)\n", 3978 QEMU_ARCH_ALL) 3979SRST 3980``-loadvm file`` 3981 Start right away with a saved state (``loadvm`` in monitor) 3982ERST 3983 3984#ifndef _WIN32 3985DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3986 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3987#endif 3988SRST 3989``-daemonize`` 3990 Daemonize the QEMU process after initialization. QEMU will not 3991 detach from standard IO until it is ready to receive connections on 3992 any of its devices. This option is a useful way for external 3993 programs to launch QEMU without having to cope with initialization 3994 race conditions. 3995ERST 3996 3997DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3998 "-option-rom rom load a file, rom, into the option ROM space\n", 3999 QEMU_ARCH_ALL) 4000SRST 4001``-option-rom file`` 4002 Load the contents of file as an option ROM. This option is useful to 4003 load things like EtherBoot. 4004ERST 4005 4006DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4007 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4008 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4009 QEMU_ARCH_ALL) 4010 4011SRST 4012``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4013 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4014 the current UTC or local time, respectively. ``localtime`` is 4015 required for correct date in MS-DOS or Windows. To start at a 4016 specific point in time, provide datetime in the format 4017 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4018 4019 By default the RTC is driven by the host system time. This allows 4020 using of the RTC as accurate reference clock inside the guest, 4021 specifically if the host time is smoothly following an accurate 4022 external reference clock, e.g. via NTP. If you want to isolate the 4023 guest time from the host, you can set ``clock`` to ``rt`` instead, 4024 which provides a host monotonic clock if host support it. To even 4025 prevent the RTC from progressing during suspension, you can set 4026 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4027 recommended especially in icount mode in order to preserve 4028 determinism; however, note that in icount mode the speed of the 4029 virtual clock is variable and can in general differ from the host 4030 clock. 4031 4032 Enable ``driftfix`` (i386 targets only) if you experience time drift 4033 problems, specifically with Windows' ACPI HAL. This option will try 4034 to figure out how many timer interrupts were not processed by the 4035 Windows guest and will re-inject them. 4036ERST 4037 4038DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4039 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4040 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4041 " instruction, enable aligning the host and virtual clocks\n" \ 4042 " or disable real time cpu sleeping, and optionally enable\n" \ 4043 " record-and-replay mode\n", QEMU_ARCH_ALL) 4044SRST 4045``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4046 Enable virtual instruction counter. The virtual cpu will execute one 4047 instruction every 2^N ns of virtual time. If ``auto`` is specified 4048 then the virtual cpu speed will be automatically adjusted to keep 4049 virtual time within a few seconds of real time. 4050 4051 Note that while this option can give deterministic behavior, it does 4052 not provide cycle accurate emulation. Modern CPUs contain 4053 superscalar out of order cores with complex cache hierarchies. The 4054 number of instructions executed often has little or no correlation 4055 with actual performance. 4056 4057 When the virtual cpu is sleeping, the virtual time will advance at 4058 default speed unless ``sleep=on`` is specified. With 4059 ``sleep=on``, the virtual time will jump to the next timer 4060 deadline instantly whenever the virtual cpu goes to sleep mode and 4061 will not advance if no timer is enabled. This behavior gives 4062 deterministic execution times from the guest point of view. 4063 The default if icount is enabled is ``sleep=off``. 4064 ``sleep=on`` cannot be used together with either ``shift=auto`` 4065 or ``align=on``. 4066 4067 ``align=on`` will activate the delay algorithm which will try to 4068 synchronise the host clock and the virtual clock. The goal is to 4069 have a guest running at the real frequency imposed by the shift 4070 option. Whenever the guest clock is behind the host clock and if 4071 ``align=on`` is specified then we print a message to the user to 4072 inform about the delay. Currently this option does not work when 4073 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4074 shift values for which the guest clock runs ahead of the host clock. 4075 Typically this happens when the shift value is high (how high 4076 depends on the host machine). The default if icount is enabled 4077 is ``align=off``. 4078 4079 When the ``rr`` option is specified deterministic record/replay is 4080 enabled. The ``rrfile=`` option must also be provided to 4081 specify the path to the replay log. In record mode data is written 4082 to this file, and in replay mode it is read back. 4083 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4084 name. In record mode, a new VM snapshot with the given name is created 4085 at the start of execution recording. In replay mode this option 4086 specifies the snapshot name used to load the initial VM state. 4087ERST 4088 4089DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4090 "-watchdog model\n" \ 4091 " enable virtual hardware watchdog [default=none]\n", 4092 QEMU_ARCH_ALL) 4093SRST 4094``-watchdog model`` 4095 Create a virtual hardware watchdog device. Once enabled (by a guest 4096 action), the watchdog must be periodically polled by an agent inside 4097 the guest or else the guest will be restarted. Choose a model for 4098 which your guest has drivers. 4099 4100 The model is the model of hardware watchdog to emulate. Use 4101 ``-watchdog help`` to list available hardware models. Only one 4102 watchdog can be enabled for a guest. 4103 4104 The following models may be available: 4105 4106 ``ib700`` 4107 iBASE 700 is a very simple ISA watchdog with a single timer. 4108 4109 ``i6300esb`` 4110 Intel 6300ESB I/O controller hub is a much more featureful 4111 PCI-based dual-timer watchdog. 4112 4113 ``diag288`` 4114 A virtual watchdog for s390x backed by the diagnose 288 4115 hypercall (currently KVM only). 4116ERST 4117 4118DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4119 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4120 " action when watchdog fires [default=reset]\n", 4121 QEMU_ARCH_ALL) 4122SRST 4123``-watchdog-action action`` 4124 The action controls what QEMU will do when the watchdog timer 4125 expires. The default is ``reset`` (forcefully reset the guest). 4126 Other possible actions are: ``shutdown`` (attempt to gracefully 4127 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4128 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4129 guest), ``debug`` (print a debug message and continue), or ``none`` 4130 (do nothing). 4131 4132 Note that the ``shutdown`` action requires that the guest responds 4133 to ACPI signals, which it may not be able to do in the sort of 4134 situations where the watchdog would have expired, and thus 4135 ``-watchdog-action shutdown`` is not recommended for production use. 4136 4137 Examples: 4138 4139 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4140 4141ERST 4142 4143DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4144 "-echr chr set terminal escape character instead of ctrl-a\n", 4145 QEMU_ARCH_ALL) 4146SRST 4147``-echr numeric_ascii_value`` 4148 Change the escape character used for switching to the monitor when 4149 using monitor and serial sharing. The default is ``0x01`` when using 4150 the ``-nographic`` option. ``0x01`` is equal to pressing 4151 ``Control-a``. You can select a different character from the ascii 4152 control keys where 1 through 26 map to Control-a through Control-z. 4153 For instance you could use the either of the following to change the 4154 escape character to Control-t. 4155 4156 ``-echr 0x14``; \ ``-echr 20`` 4157 4158ERST 4159 4160DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4161 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4162 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4163 "-incoming unix:socketpath\n" \ 4164 " prepare for incoming migration, listen on\n" \ 4165 " specified protocol and socket address\n" \ 4166 "-incoming fd:fd\n" \ 4167 "-incoming exec:cmdline\n" \ 4168 " accept incoming migration on given file descriptor\n" \ 4169 " or from given external command\n" \ 4170 "-incoming defer\n" \ 4171 " wait for the URI to be specified via migrate_incoming\n", 4172 QEMU_ARCH_ALL) 4173SRST 4174``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4175 \ 4176``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4177 Prepare for incoming migration, listen on a given tcp port. 4178 4179``-incoming unix:socketpath`` 4180 Prepare for incoming migration, listen on a given unix socket. 4181 4182``-incoming fd:fd`` 4183 Accept incoming migration from a given filedescriptor. 4184 4185``-incoming exec:cmdline`` 4186 Accept incoming migration as an output from specified external 4187 command. 4188 4189``-incoming defer`` 4190 Wait for the URI to be specified via migrate\_incoming. The monitor 4191 can be used to change settings (such as migration parameters) prior 4192 to issuing the migrate\_incoming to allow the migration to begin. 4193ERST 4194 4195DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4196 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4197SRST 4198``-only-migratable`` 4199 Only allow migratable devices. Devices will not be allowed to enter 4200 an unmigratable state. 4201ERST 4202 4203DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4204 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4205SRST 4206``-nodefaults`` 4207 Don't create default devices. Normally, QEMU sets the default 4208 devices like serial port, parallel port, virtual console, monitor 4209 device, VGA adapter, floppy and CD-ROM drive and others. The 4210 ``-nodefaults`` option will disable all those default devices. 4211ERST 4212 4213#ifndef _WIN32 4214DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4215 "-chroot dir chroot to dir just before starting the VM\n", 4216 QEMU_ARCH_ALL) 4217#endif 4218SRST 4219``-chroot dir`` 4220 Immediately before starting guest execution, chroot to the specified 4221 directory. Especially useful in combination with -runas. 4222ERST 4223 4224#ifndef _WIN32 4225DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4226 "-runas user change to user id user just before starting the VM\n" \ 4227 " user can be numeric uid:gid instead\n", 4228 QEMU_ARCH_ALL) 4229#endif 4230SRST 4231``-runas user`` 4232 Immediately before starting guest execution, drop root privileges, 4233 switching to the specified user. 4234ERST 4235 4236DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4237 "-prom-env variable=value\n" 4238 " set OpenBIOS nvram variables\n", 4239 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4240SRST 4241``-prom-env variable=value`` 4242 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4243 4244 :: 4245 4246 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4247 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4248 4249 :: 4250 4251 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4252 -prom-env 'boot-device=hd:2,\yaboot' \ 4253 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4254ERST 4255DEF("semihosting", 0, QEMU_OPTION_semihosting, 4256 "-semihosting semihosting mode\n", 4257 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4258 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4259SRST 4260``-semihosting`` 4261 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4262 4263 Note that this allows guest direct access to the host filesystem, so 4264 should only be used with a trusted guest OS. 4265 4266 See the -semihosting-config option documentation for further 4267 information about the facilities this enables. 4268ERST 4269DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4270 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4271 " semihosting configuration\n", 4272QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4273QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4274SRST 4275``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4276 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4277 only). 4278 4279 Note that this allows guest direct access to the host filesystem, so 4280 should only be used with a trusted guest OS. 4281 4282 On Arm this implements the standard semihosting API, version 2.0. 4283 4284 On M68K this implements the "ColdFire GDB" interface used by 4285 libgloss. 4286 4287 Xtensa semihosting provides basic file IO calls, such as 4288 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4289 linux platform "sim" use this interface. 4290 4291 On RISC-V this implements the standard semihosting API, version 0.2. 4292 4293 ``target=native|gdb|auto`` 4294 Defines where the semihosting calls will be addressed, to QEMU 4295 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4296 means ``gdb`` during debug sessions and ``native`` otherwise. 4297 4298 ``chardev=str1`` 4299 Send the output to a chardev backend output for native or auto 4300 output when not in gdb 4301 4302 ``arg=str1,arg=str2,...`` 4303 Allows the user to pass input arguments, and can be used 4304 multiple times to build up a list. The old-style 4305 ``-kernel``/``-append`` method of passing a command line is 4306 still supported for backward compatibility. If both the 4307 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4308 specified, the former is passed to semihosting as it always 4309 takes precedence. 4310ERST 4311DEF("old-param", 0, QEMU_OPTION_old_param, 4312 "-old-param old param mode\n", QEMU_ARCH_ARM) 4313SRST 4314``-old-param`` 4315 Old param mode (ARM only). 4316ERST 4317 4318DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4319 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4320 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4321 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4322 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4323 " by the kernel, but typically no longer used by modern\n" \ 4324 " C library implementations.\n" \ 4325 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4326 " to elevate privileges using set*uid|gid system calls.\n" \ 4327 " The value 'children' will deny set*uid|gid system calls for\n" \ 4328 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4329 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4330 " blocking *fork and execve\n" \ 4331 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4332 QEMU_ARCH_ALL) 4333SRST 4334``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4335 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4336 filtering and 'off' will disable it. The default is 'off'. 4337 4338 ``obsolete=string`` 4339 Enable Obsolete system calls 4340 4341 ``elevateprivileges=string`` 4342 Disable set\*uid\|gid system calls 4343 4344 ``spawn=string`` 4345 Disable \*fork and execve 4346 4347 ``resourcecontrol=string`` 4348 Disable process affinity and schedular priority 4349ERST 4350 4351DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4352 "-readconfig <file>\n", QEMU_ARCH_ALL) 4353SRST 4354``-readconfig file`` 4355 Read device configuration from file. This approach is useful when 4356 you want to spawn QEMU process with many command line options but 4357 you don't want to exceed the command line character limit. 4358ERST 4359DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4360 "-writeconfig <file>\n" 4361 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4362SRST 4363ERST 4364 4365DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4366 "-no-user-config\n" 4367 " do not load default user-provided config files at startup\n", 4368 QEMU_ARCH_ALL) 4369SRST 4370``-no-user-config`` 4371 The ``-no-user-config`` option makes QEMU not load any of the 4372 user-provided config files on sysconfdir. 4373ERST 4374 4375DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4376 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4377 " specify tracing options\n", 4378 QEMU_ARCH_ALL) 4379SRST 4380``-trace [[enable=]pattern][,events=file][,file=file]`` 4381 .. include:: ../qemu-option-trace.rst.inc 4382 4383ERST 4384DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4385 "-plugin [file=]<file>[,arg=<string>]\n" 4386 " load a plugin\n", 4387 QEMU_ARCH_ALL) 4388SRST 4389``-plugin file=file[,arg=string]`` 4390 Load a plugin. 4391 4392 ``file=file`` 4393 Load the given plugin from a shared library file. 4394 4395 ``arg=string`` 4396 Argument string passed to the plugin. (Can be given multiple 4397 times.) 4398ERST 4399 4400HXCOMM Internal use 4401DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4402DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4403 4404#ifdef __linux__ 4405DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4406 "-enable-fips enable FIPS 140-2 compliance\n", 4407 QEMU_ARCH_ALL) 4408#endif 4409SRST 4410``-enable-fips`` 4411 Enable FIPS 140-2 compliance mode. 4412ERST 4413 4414DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4415 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4416 " control error message format\n" 4417 " timestamp=on enables timestamps (default: off)\n" 4418 " guest-name=on enables guest name prefix but only if\n" 4419 " -name guest option is set (default: off)\n", 4420 QEMU_ARCH_ALL) 4421SRST 4422``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4423 Control error message format. 4424 4425 ``timestamp=on|off`` 4426 Prefix messages with a timestamp. Default is off. 4427 4428 ``guest-name=on|off`` 4429 Prefix messages with guest name but only if -name guest option is set 4430 otherwise the option is ignored. Default is off. 4431ERST 4432 4433DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4434 "-dump-vmstate <file>\n" 4435 " Output vmstate information in JSON format to file.\n" 4436 " Use the scripts/vmstate-static-checker.py file to\n" 4437 " check for possible regressions in migration code\n" 4438 " by comparing two such vmstate dumps.\n", 4439 QEMU_ARCH_ALL) 4440SRST 4441``-dump-vmstate file`` 4442 Dump json-encoded vmstate information for current machine type to 4443 file in file 4444ERST 4445 4446DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4447 "-enable-sync-profile\n" 4448 " enable synchronization profiling\n", 4449 QEMU_ARCH_ALL) 4450SRST 4451``-enable-sync-profile`` 4452 Enable synchronization profiling. 4453ERST 4454 4455DEFHEADING() 4456 4457DEFHEADING(Generic object creation:) 4458 4459DEF("object", HAS_ARG, QEMU_OPTION_object, 4460 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4461 " create a new object of type TYPENAME setting properties\n" 4462 " in the order they are specified. Note that the 'id'\n" 4463 " property must be set. These objects are placed in the\n" 4464 " '/objects' path.\n", 4465 QEMU_ARCH_ALL) 4466SRST 4467``-object typename[,prop1=value1,...]`` 4468 Create a new object of type typename setting properties in the order 4469 they are specified. Note that the 'id' property must be set. These 4470 objects are placed in the '/objects' path. 4471 4472 ``-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,readonly=on|off`` 4473 Creates a memory file backend object, which can be used to back 4474 the guest RAM with huge pages. 4475 4476 The ``id`` parameter is a unique ID that will be used to 4477 reference this memory region when configuring the ``-numa`` 4478 argument. 4479 4480 The ``size`` option provides the size of the memory region, and 4481 accepts common suffixes, eg ``500M``. 4482 4483 The ``mem-path`` provides the path to either a shared memory or 4484 huge page filesystem mount. 4485 4486 The ``share`` boolean option determines whether the memory 4487 region is marked as private to QEMU, or shared. The latter 4488 allows a co-operating external process to access the QEMU memory 4489 region. 4490 4491 The ``share`` is also required for pvrdma devices due to 4492 limitations in the RDMA API provided by Linux. 4493 4494 Setting share=on might affect the ability to configure NUMA 4495 bindings for the memory backend under some circumstances, see 4496 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4497 source tree for additional details. 4498 4499 Setting the ``discard-data`` boolean option to on indicates that 4500 file contents can be destroyed when QEMU exits, to avoid 4501 unnecessarily flushing data to the backing file. Note that 4502 ``discard-data`` is only an optimization, and QEMU might not 4503 discard file contents if it aborts unexpectedly or is terminated 4504 using SIGKILL. 4505 4506 The ``merge`` boolean option enables memory merge, also known as 4507 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4508 the pages for memory deduplication. 4509 4510 Setting the ``dump`` boolean option to off excludes the memory 4511 from core dumps. This feature is also known as MADV\_DONTDUMP. 4512 4513 The ``prealloc`` boolean option enables memory preallocation. 4514 4515 The ``host-nodes`` option binds the memory range to a list of 4516 NUMA host nodes. 4517 4518 The ``policy`` option sets the NUMA policy to one of the 4519 following values: 4520 4521 ``default`` 4522 default host policy 4523 4524 ``preferred`` 4525 prefer the given host node list for allocation 4526 4527 ``bind`` 4528 restrict memory allocation to the given host node list 4529 4530 ``interleave`` 4531 interleave memory allocations across the given host node 4532 list 4533 4534 The ``align`` option specifies the base address alignment when 4535 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4536 ``2M``. Some backend store specified by ``mem-path`` requires an 4537 alignment different than the default one used by QEMU, eg the 4538 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4539 such cases, users can specify the required alignment via this 4540 option. 4541 4542 The ``pmem`` option specifies whether the backing file specified 4543 by ``mem-path`` is in host persistent memory that can be 4544 accessed using the SNIA NVM programming model (e.g. Intel 4545 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4546 operations to guarantee the persistence of its own writes to 4547 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4548 migration). Also, we will map the backend-file with MAP\_SYNC 4549 flag, which ensures the file metadata is in sync for 4550 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4551 requires support from both the host kernel (since Linux kernel 4552 4.15) and the filesystem of ``mem-path`` mounted with DAX 4553 option. 4554 4555 The ``readonly`` option specifies whether the backing file is opened 4556 read-only or read-write (default). 4557 4558 ``-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`` 4559 Creates a memory backend object, which can be used to back the 4560 guest RAM. Memory backend objects offer more control than the 4561 ``-m`` option that is traditionally used to define guest RAM. 4562 Please refer to ``memory-backend-file`` for a description of the 4563 options. 4564 4565 ``-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`` 4566 Creates an anonymous memory file backend object, which allows 4567 QEMU to share the memory with an external process (e.g. when 4568 using vhost-user). The memory is allocated with memfd and 4569 optional sealing. (Linux only) 4570 4571 The ``seal`` option creates a sealed-file, that will block 4572 further resizing the memory ('on' by default). 4573 4574 The ``hugetlb`` option specify the file to be created resides in 4575 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4576 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4577 the hugetlb page size on systems that support multiple hugetlb 4578 page sizes (it must be a power of 2 value supported by the 4579 system). 4580 4581 In some versions of Linux, the ``hugetlb`` option is 4582 incompatible with the ``seal`` option (requires at least Linux 4583 4.16). 4584 4585 Please refer to ``memory-backend-file`` for a description of the 4586 other options. 4587 4588 The ``share`` boolean option is on by default with memfd. 4589 4590 ``-object rng-builtin,id=id`` 4591 Creates a random number generator backend which obtains entropy 4592 from QEMU builtin functions. The ``id`` parameter is a unique ID 4593 that will be used to reference this entropy backend from the 4594 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4595 uses this RNG backend. 4596 4597 ``-object rng-random,id=id,filename=/dev/random`` 4598 Creates a random number generator backend which obtains entropy 4599 from a device on the host. The ``id`` parameter is a unique ID 4600 that will be used to reference this entropy backend from the 4601 ``virtio-rng`` device. The ``filename`` parameter specifies 4602 which file to obtain entropy from and if omitted defaults to 4603 ``/dev/urandom``. 4604 4605 ``-object rng-egd,id=id,chardev=chardevid`` 4606 Creates a random number generator backend which obtains entropy 4607 from an external daemon running on the host. The ``id`` 4608 parameter is a unique ID that will be used to reference this 4609 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4610 parameter is the unique ID of a character device backend that 4611 provides the connection to the RNG daemon. 4612 4613 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4614 Creates a TLS anonymous credentials object, which can be used to 4615 provide TLS support on network backends. The ``id`` parameter is 4616 a unique ID which network backends will use to access the 4617 credentials. The ``endpoint`` is either ``server`` or ``client`` 4618 depending on whether the QEMU network backend that uses the 4619 credentials will be acting as a client or as a server. If 4620 ``verify-peer`` is enabled (the default) then once the handshake 4621 is completed, the peer credentials will be verified, though this 4622 is a no-op for anonymous credentials. 4623 4624 The dir parameter tells QEMU where to find the credential files. 4625 For server endpoints, this directory may contain a file 4626 dh-params.pem providing diffie-hellman parameters to use for the 4627 TLS server. If the file is missing, QEMU will generate a set of 4628 DH parameters at startup. This is a computationally expensive 4629 operation that consumes random pool entropy, so it is 4630 recommended that a persistent set of parameters be generated 4631 upfront and saved. 4632 4633 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4634 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4635 can be used to provide TLS support on network backends. The 4636 ``id`` parameter is a unique ID which network backends will use 4637 to access the credentials. The ``endpoint`` is either ``server`` 4638 or ``client`` depending on whether the QEMU network backend that 4639 uses the credentials will be acting as a client or as a server. 4640 For clients only, ``username`` is the username which will be 4641 sent to the server. If omitted it defaults to "qemu". 4642 4643 The dir parameter tells QEMU where to find the keys file. It is 4644 called "dir/keys.psk" and contains "username:key" pairs. This 4645 file can most easily be created using the GnuTLS ``psktool`` 4646 program. 4647 4648 For server endpoints, dir may also contain a file dh-params.pem 4649 providing diffie-hellman parameters to use for the TLS server. 4650 If the file is missing, QEMU will generate a set of DH 4651 parameters at startup. This is a computationally expensive 4652 operation that consumes random pool entropy, so it is 4653 recommended that a persistent set of parameters be generated up 4654 front and saved. 4655 4656 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4657 Creates a TLS anonymous credentials object, which can be used to 4658 provide TLS support on network backends. The ``id`` parameter is 4659 a unique ID which network backends will use to access the 4660 credentials. The ``endpoint`` is either ``server`` or ``client`` 4661 depending on whether the QEMU network backend that uses the 4662 credentials will be acting as a client or as a server. If 4663 ``verify-peer`` is enabled (the default) then once the handshake 4664 is completed, the peer credentials will be verified. With x509 4665 certificates, this implies that the clients must be provided 4666 with valid client certificates too. 4667 4668 The dir parameter tells QEMU where to find the credential files. 4669 For server endpoints, this directory may contain a file 4670 dh-params.pem providing diffie-hellman parameters to use for the 4671 TLS server. If the file is missing, QEMU will generate a set of 4672 DH parameters at startup. This is a computationally expensive 4673 operation that consumes random pool entropy, so it is 4674 recommended that a persistent set of parameters be generated 4675 upfront and saved. 4676 4677 For x509 certificate credentials the directory will contain 4678 further files providing the x509 certificates. The certificates 4679 must be stored in PEM format, in filenames ca-cert.pem, 4680 ca-crl.pem (optional), server-cert.pem (only servers), 4681 server-key.pem (only servers), client-cert.pem (only clients), 4682 and client-key.pem (only clients). 4683 4684 For the server-key.pem and client-key.pem files which contain 4685 sensitive private keys, it is possible to use an encrypted 4686 version by providing the passwordid parameter. This provides the 4687 ID of a previously created ``secret`` object containing the 4688 password for decryption. 4689 4690 The priority parameter allows to override the global default 4691 priority used by gnutls. This can be useful if the system 4692 administrator needs to use a weaker set of crypto priorities for 4693 QEMU without potentially forcing the weakness onto all 4694 applications. Or conversely if one wants wants a stronger 4695 default for QEMU than for all other applications, they can do 4696 this through this parameter. Its format is a gnutls priority 4697 string as described at 4698 https://gnutls.org/manual/html_node/Priority-Strings.html. 4699 4700 ``-object tls-cipher-suites,id=id,priority=priority`` 4701 Creates a TLS cipher suites object, which can be used to control 4702 the TLS cipher/protocol algorithms that applications are permitted 4703 to use. 4704 4705 The ``id`` parameter is a unique ID which frontends will use to 4706 access the ordered list of permitted TLS cipher suites from the 4707 host. 4708 4709 The ``priority`` parameter allows to override the global default 4710 priority used by gnutls. This can be useful if the system 4711 administrator needs to use a weaker set of crypto priorities for 4712 QEMU without potentially forcing the weakness onto all 4713 applications. Or conversely if one wants wants a stronger 4714 default for QEMU than for all other applications, they can do 4715 this through this parameter. Its format is a gnutls priority 4716 string as described at 4717 https://gnutls.org/manual/html_node/Priority-Strings.html. 4718 4719 An example of use of this object is to control UEFI HTTPS Boot. 4720 The tls-cipher-suites object exposes the ordered list of permitted 4721 TLS cipher suites from the host side to the guest firmware, via 4722 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4723 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4724 guest-side TLS. 4725 4726 In the following example, the priority at which the host-side policy 4727 is retrieved is given by the ``priority`` property. 4728 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4729 refer to /etc/crypto-policies/back-ends/gnutls.config. 4730 4731 .. parsed-literal:: 4732 4733 # |qemu_system| \\ 4734 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4735 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4736 4737 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4738 Interval t can't be 0, this filter batches the packet delivery: 4739 all packets arriving in a given interval on netdev netdevid are 4740 delayed until the end of the interval. Interval is in 4741 microseconds. ``status`` is optional that indicate whether the 4742 netfilter is on (enabled) or off (disabled), the default status 4743 for netfilter will be 'on'. 4744 4745 queue all\|rx\|tx is an option that can be applied to any 4746 netfilter. 4747 4748 ``all``: the filter is attached both to the receive and the 4749 transmit queue of the netdev (default). 4750 4751 ``rx``: the filter is attached to the receive queue of the 4752 netdev, where it will receive packets sent to the netdev. 4753 4754 ``tx``: the filter is attached to the transmit queue of the 4755 netdev, where it will receive packets sent by the netdev. 4756 4757 position head\|tail\|id=<id> is an option to specify where the 4758 filter should be inserted in the filter list. It can be applied 4759 to any netfilter. 4760 4761 ``head``: the filter is inserted at the head of the filter list, 4762 before any existing filters. 4763 4764 ``tail``: the filter is inserted at the tail of the filter list, 4765 behind any existing filters (default). 4766 4767 ``id=<id>``: the filter is inserted before or behind the filter 4768 specified by <id>, see the insert option below. 4769 4770 insert behind\|before is an option to specify where to insert 4771 the new filter relative to the one specified with 4772 position=id=<id>. It can be applied to any netfilter. 4773 4774 ``before``: insert before the specified filter. 4775 4776 ``behind``: insert behind the specified filter (default). 4777 4778 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4779 filter-mirror on netdev netdevid,mirror net packet to 4780 chardevchardevid, if it has the vnet\_hdr\_support flag, 4781 filter-mirror will mirror packet with vnet\_hdr\_len. 4782 4783 ``-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]`` 4784 filter-redirector on netdev netdevid,redirect filter's net 4785 packet to chardev chardevid,and redirect indev's packet to 4786 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4787 will redirect packet with vnet\_hdr\_len. Create a 4788 filter-redirector we need to differ outdev id from indev id, id 4789 can not be the same. we can just use indev or outdev, but at 4790 least one of indev or outdev need to be specified. 4791 4792 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4793 Filter-rewriter is a part of COLO project.It will rewrite tcp 4794 packet to secondary from primary to keep secondary tcp 4795 connection,and rewrite tcp packet to primary from secondary make 4796 tcp packet can be handled by client.if it has the 4797 vnet\_hdr\_support flag, we can parse packet with vnet header. 4798 4799 usage: colo secondary: -object 4800 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4801 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4802 filter-rewriter,id=rew0,netdev=hn0,queue=all 4803 4804 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4805 Dump the network traffic on netdev dev to the file specified by 4806 filename. At most len bytes (64k by default) per packet are 4807 stored. The file format is libpcap, so it can be analyzed with 4808 tools such as tcpdump or Wireshark. 4809 4810 ``-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}]`` 4811 Colo-compare gets packet from primary\_in chardevid and 4812 secondary\_in, then compare whether the payload of primary packet 4813 and secondary packet are the same. If same, it will output 4814 primary packet to out\_dev, else it will notify COLO-framework to do 4815 checkpoint and send primary packet to out\_dev. In order to 4816 improve efficiency, we need to put the task of comparison in 4817 another iothread. If it has the vnet\_hdr\_support flag, 4818 colo compare will send/recv packet with vnet\_hdr\_len. 4819 The compare\_timeout=@var{ms} determines the maximum time of the 4820 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4821 is to set the period of scanning expired primary node network packets. 4822 The max\_queue\_size=@var{size} is to set the max compare queue 4823 size depend on user environment. 4824 If user want to use Xen COLO, need to add the notify\_dev to 4825 notify Xen colo-frame to do checkpoint. 4826 4827 COLO-compare must be used with the help of filter-mirror, 4828 filter-redirector and filter-rewriter. 4829 4830 :: 4831 4832 KVM COLO 4833 4834 primary: 4835 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4836 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4837 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4838 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4839 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4840 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4841 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4842 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4843 -object iothread,id=iothread1 4844 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4845 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4846 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4847 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4848 4849 secondary: 4850 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4851 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4852 -chardev socket,id=red0,host=3.3.3.3,port=9003 4853 -chardev socket,id=red1,host=3.3.3.3,port=9004 4854 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4855 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4856 4857 4858 Xen COLO 4859 4860 primary: 4861 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4862 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4863 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4864 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4865 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4866 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4867 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4868 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4869 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4870 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4871 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4872 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4873 -object iothread,id=iothread1 4874 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4875 4876 secondary: 4877 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4878 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4879 -chardev socket,id=red0,host=3.3.3.3,port=9003 4880 -chardev socket,id=red1,host=3.3.3.3,port=9004 4881 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4882 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4883 4884 If you want to know the detail of above command line, you can 4885 read the colo-compare git log. 4886 4887 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4888 Creates a cryptodev backend which executes crypto opreation from 4889 the QEMU cipher APIS. The id parameter is a unique ID that will 4890 be used to reference this cryptodev backend from the 4891 ``virtio-crypto`` device. The queues parameter is optional, 4892 which specify the queue number of cryptodev backend, the default 4893 of queues is 1. 4894 4895 .. parsed-literal:: 4896 4897 # |qemu_system| \\ 4898 [...] \\ 4899 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4900 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4901 [...] 4902 4903 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4904 Creates a vhost-user cryptodev backend, backed by a chardev 4905 chardevid. The id parameter is a unique ID that will be used to 4906 reference this cryptodev backend from the ``virtio-crypto`` 4907 device. The chardev should be a unix domain socket backed one. 4908 The vhost-user uses a specifically defined protocol to pass 4909 vhost ioctl replacement messages to an application on the other 4910 end of the socket. The queues parameter is optional, which 4911 specify the queue number of cryptodev backend for multiqueue 4912 vhost-user, the default of queues is 1. 4913 4914 .. parsed-literal:: 4915 4916 # |qemu_system| \\ 4917 [...] \\ 4918 -chardev socket,id=chardev0,path=/path/to/socket \\ 4919 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4920 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4921 [...] 4922 4923 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 4924 \ 4925 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 4926 Defines a secret to store a password, encryption key, or some 4927 other sensitive data. The sensitive data can either be passed 4928 directly via the data parameter, or indirectly via the file 4929 parameter. Using the data parameter is insecure unless the 4930 sensitive data is encrypted. 4931 4932 The sensitive data can be provided in raw format (the default), 4933 or base64. When encoded as JSON, the raw format only supports 4934 valid UTF-8 characters, so base64 is recommended for sending 4935 binary data. QEMU will convert from which ever format is 4936 provided to the format it needs internally. eg, an RBD password 4937 can be provided in raw format, even though it will be base64 4938 encoded when passed onto the RBD sever. 4939 4940 For added protection, it is possible to encrypt the data 4941 associated with a secret using the AES-256-CBC cipher. Use of 4942 encryption is indicated by providing the keyid and iv 4943 parameters. The keyid parameter provides the ID of a previously 4944 defined secret that contains the AES-256 decryption key. This 4945 key should be 32-bytes long and be base64 encoded. The iv 4946 parameter provides the random initialization vector used for 4947 encryption of this particular secret and should be a base64 4948 encrypted string of the 16-byte IV. 4949 4950 The simplest (insecure) usage is to provide the secret inline 4951 4952 .. parsed-literal:: 4953 4954 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 4955 4956 The simplest secure usage is to provide the secret via a file 4957 4958 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 4959 secret,id=sec0,file=mypasswd.txt,format=raw 4960 4961 For greater security, AES-256-CBC should be used. To illustrate 4962 usage, consider the openssl command line tool which can encrypt 4963 the data. Note that when encrypting, the plaintext must be 4964 padded to the cipher block size (32 bytes) using the standard 4965 PKCS#5/6 compatible padding algorithm. 4966 4967 First a master key needs to be created in base64 encoding: 4968 4969 :: 4970 4971 # openssl rand -base64 32 > key.b64 4972 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4973 4974 Each secret to be encrypted needs to have a random 4975 initialization vector generated. These do not need to be kept 4976 secret 4977 4978 :: 4979 4980 # openssl rand -base64 16 > iv.b64 4981 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4982 4983 The secret to be defined can now be encrypted, in this case 4984 we're telling openssl to base64 encode the result, but it could 4985 be left as raw bytes if desired. 4986 4987 :: 4988 4989 # SECRET=$(printf "letmein" | 4990 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4991 4992 When launching QEMU, create a master secret pointing to 4993 ``key.b64`` and specify that to be used to decrypt the user 4994 password. Pass the contents of ``iv.b64`` to the second secret 4995 4996 .. parsed-literal:: 4997 4998 # |qemu_system| \\ 4999 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5000 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5001 data=$SECRET,iv=$(<iv.b64) 5002 5003 ``-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]`` 5004 Create a Secure Encrypted Virtualization (SEV) guest object, 5005 which can be used to provide the guest memory encryption support 5006 on AMD processors. 5007 5008 When memory encryption is enabled, one of the physical address 5009 bit (aka the C-bit) is utilized to mark if a memory page is 5010 protected. The ``cbitpos`` is used to provide the C-bit 5011 position. The C-bit position is Host family dependent hence user 5012 must provide this value. On EPYC, the value should be 47. 5013 5014 When memory encryption is enabled, we loose certain bits in 5015 physical address space. The ``reduced-phys-bits`` is used to 5016 provide the number of bits we loose in physical address space. 5017 Similar to C-bit, the value is Host family dependent. On EPYC, 5018 the value should be 5. 5019 5020 The ``sev-device`` provides the device file to use for 5021 communicating with the SEV firmware running inside AMD Secure 5022 Processor. The default device is '/dev/sev'. If hardware 5023 supports memory encryption then /dev/sev devices are created by 5024 CCP driver. 5025 5026 The ``policy`` provides the guest policy to be enforced by the 5027 SEV firmware and restrict what configuration and operational 5028 commands can be performed on this guest by the hypervisor. The 5029 policy should be provided by the guest owner and is bound to the 5030 guest and cannot be changed throughout the lifetime of the 5031 guest. The default is 0. 5032 5033 If guest ``policy`` allows sharing the key with another SEV 5034 guest then ``handle`` can be use to provide handle of the guest 5035 from which to share the key. 5036 5037 The ``dh-cert-file`` and ``session-file`` provides the guest 5038 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5039 and session parameters are used for establishing a cryptographic 5040 session with the guest owner to negotiate keys used for 5041 attestation. The file must be encoded in base64. 5042 5043 e.g to launch a SEV guest 5044 5045 .. parsed-literal:: 5046 5047 # |qemu_system_x86| \\ 5048 ...... \\ 5049 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5050 -machine ...,memory-encryption=sev0 \\ 5051 ..... 5052 5053 ``-object authz-simple,id=id,identity=string`` 5054 Create an authorization object that will control access to 5055 network services. 5056 5057 The ``identity`` parameter is identifies the user and its format 5058 depends on the network service that authorization object is 5059 associated with. For authorizing based on TLS x509 certificates, 5060 the identity must be the x509 distinguished name. Note that care 5061 must be taken to escape any commas in the distinguished name. 5062 5063 An example authorization object to validate a x509 distinguished 5064 name would look like: 5065 5066 .. parsed-literal:: 5067 5068 # |qemu_system| \\ 5069 ... \\ 5070 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5071 ... 5072 5073 Note the use of quotes due to the x509 distinguished name 5074 containing whitespace, and escaping of ','. 5075 5076 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5077 Create an authorization object that will control access to 5078 network services. 5079 5080 The ``filename`` parameter is the fully qualified path to a file 5081 containing the access control list rules in JSON format. 5082 5083 An example set of rules that match against SASL usernames might 5084 look like: 5085 5086 :: 5087 5088 { 5089 "rules": [ 5090 { "match": "fred", "policy": "allow", "format": "exact" }, 5091 { "match": "bob", "policy": "allow", "format": "exact" }, 5092 { "match": "danb", "policy": "deny", "format": "glob" }, 5093 { "match": "dan*", "policy": "allow", "format": "exact" }, 5094 ], 5095 "policy": "deny" 5096 } 5097 5098 When checking access the object will iterate over all the rules 5099 and the first rule to match will have its ``policy`` value 5100 returned as the result. If no rules match, then the default 5101 ``policy`` value is returned. 5102 5103 The rules can either be an exact string match, or they can use 5104 the simple UNIX glob pattern matching to allow wildcards to be 5105 used. 5106 5107 If ``refresh`` is set to true the file will be monitored and 5108 automatically reloaded whenever its content changes. 5109 5110 As with the ``authz-simple`` object, the format of the identity 5111 strings being matched depends on the network service, but is 5112 usually a TLS x509 distinguished name, or a SASL username. 5113 5114 An example authorization object to validate a SASL username 5115 would look like: 5116 5117 .. parsed-literal:: 5118 5119 # |qemu_system| \\ 5120 ... \\ 5121 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5122 ... 5123 5124 ``-object authz-pam,id=id,service=string`` 5125 Create an authorization object that will control access to 5126 network services. 5127 5128 The ``service`` parameter provides the name of a PAM service to 5129 use for authorization. It requires that a file 5130 ``/etc/pam.d/service`` exist to provide the configuration for 5131 the ``account`` subsystem. 5132 5133 An example authorization object to validate a TLS x509 5134 distinguished name would look like: 5135 5136 .. parsed-literal:: 5137 5138 # |qemu_system| \\ 5139 ... \\ 5140 -object authz-pam,id=auth0,service=qemu-vnc \\ 5141 ... 5142 5143 There would then be a corresponding config file for PAM at 5144 ``/etc/pam.d/qemu-vnc`` that contains: 5145 5146 :: 5147 5148 account requisite pam_listfile.so item=user sense=allow \ 5149 file=/etc/qemu/vnc.allow 5150 5151 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5152 of x509 distingished names that are permitted access 5153 5154 :: 5155 5156 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5157 5158 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5159 Creates a dedicated event loop thread that devices can be 5160 assigned to. This is known as an IOThread. By default device 5161 emulation happens in vCPU threads or the main event loop thread. 5162 This can become a scalability bottleneck. IOThreads allow device 5163 emulation and I/O to run on other host CPUs. 5164 5165 The ``id`` parameter is a unique ID that will be used to 5166 reference this IOThread from ``-device ...,iothread=id``. 5167 Multiple devices can be assigned to an IOThread. Note that not 5168 all devices support an ``iothread`` parameter. 5169 5170 The ``query-iothreads`` QMP command lists IOThreads and reports 5171 their thread IDs so that the user can configure host CPU 5172 pinning/affinity. 5173 5174 IOThreads use an adaptive polling algorithm to reduce event loop 5175 latency. Instead of entering a blocking system call to monitor 5176 file descriptors and then pay the cost of being woken up when an 5177 event occurs, the polling algorithm spins waiting for events for 5178 a short time. The algorithm's default parameters are suitable 5179 for many cases but can be adjusted based on knowledge of the 5180 workload and/or host device latency. 5181 5182 The ``poll-max-ns`` parameter is the maximum number of 5183 nanoseconds to busy wait for events. Polling can be disabled by 5184 setting this value to 0. 5185 5186 The ``poll-grow`` parameter is the multiplier used to increase 5187 the polling time when the algorithm detects it is missing events 5188 due to not polling long enough. 5189 5190 The ``poll-shrink`` parameter is the divisor used to decrease 5191 the polling time when the algorithm detects it is spending too 5192 long polling without encountering events. 5193 5194 The polling parameters can be modified at run-time using the 5195 ``qom-set`` command (where ``iothread1`` is the IOThread's 5196 ``id``): 5197 5198 :: 5199 5200 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5201ERST 5202 5203 5204HXCOMM This is the last statement. Insert new options before this line! 5205
