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 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. Note that this option is deprecated, 1727 please use ``-device usb-...`` instead. See the chapter about 1728 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1729 1730 ``mouse`` 1731 Virtual Mouse. This will override the PS/2 mouse emulation when 1732 activated. 1733 1734 ``tablet`` 1735 Pointer device that uses absolute coordinates (like a 1736 touchscreen). This means QEMU is able to report the mouse 1737 position without having to grab the mouse. Also overrides the 1738 PS/2 mouse emulation when activated. 1739 1740 ``braille`` 1741 Braille device. This will use BrlAPI to display the braille 1742 output on a real or fake device. 1743ERST 1744 1745DEFHEADING() 1746 1747DEFHEADING(Display options:) 1748 1749DEF("display", HAS_ARG, QEMU_OPTION_display, 1750#if defined(CONFIG_SPICE) 1751 "-display spice-app[,gl=on|off]\n" 1752#endif 1753#if defined(CONFIG_SDL) 1754 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1755 " [,window_close=on|off][,gl=on|core|es|off]\n" 1756#endif 1757#if defined(CONFIG_GTK) 1758 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1759#endif 1760#if defined(CONFIG_VNC) 1761 "-display vnc=<display>[,<optargs>]\n" 1762#endif 1763#if defined(CONFIG_CURSES) 1764 "-display curses[,charset=<encoding>]\n" 1765#endif 1766#if defined(CONFIG_OPENGL) 1767 "-display egl-headless[,rendernode=<file>]\n" 1768#endif 1769 "-display none\n" 1770 " select display backend type\n" 1771 " The default display is equivalent to\n " 1772#if defined(CONFIG_GTK) 1773 "\"-display gtk\"\n" 1774#elif defined(CONFIG_SDL) 1775 "\"-display sdl\"\n" 1776#elif defined(CONFIG_COCOA) 1777 "\"-display cocoa\"\n" 1778#elif defined(CONFIG_VNC) 1779 "\"-vnc localhost:0,to=99,id=default\"\n" 1780#else 1781 "\"-display none\"\n" 1782#endif 1783 , QEMU_ARCH_ALL) 1784SRST 1785``-display type`` 1786 Select type of display to use. This option is a replacement for the 1787 old style -sdl/-curses/... options. Use ``-display help`` to list 1788 the available display types. Valid values for type are 1789 1790 ``sdl`` 1791 Display video output via SDL (usually in a separate graphics 1792 window; see the SDL documentation for other possibilities). 1793 1794 ``curses`` 1795 Display video output via curses. For graphics device models 1796 which support a text mode, QEMU can display this output using a 1797 curses/ncurses interface. Nothing is displayed when the graphics 1798 device is in graphical mode or if the graphics device does not 1799 support a text mode. Generally only the VGA device models 1800 support text mode. The font charset used by the guest can be 1801 specified with the ``charset`` option, for example 1802 ``charset=CP850`` for IBM CP850 encoding. The default is 1803 ``CP437``. 1804 1805 ``none`` 1806 Do not display video output. The guest will still see an 1807 emulated graphics card, but its output will not be displayed to 1808 the QEMU user. This option differs from the -nographic option in 1809 that it only affects what is done with video output; -nographic 1810 also changes the destination of the serial and parallel port 1811 data. 1812 1813 ``gtk`` 1814 Display video output in a GTK window. This interface provides 1815 drop-down menus and other UI elements to configure and control 1816 the VM during runtime. 1817 1818 ``vnc`` 1819 Start a VNC server on display <arg> 1820 1821 ``egl-headless`` 1822 Offload all OpenGL operations to a local DRI device. For any 1823 graphical display, this display needs to be paired with either 1824 VNC or SPICE displays. 1825 1826 ``spice-app`` 1827 Start QEMU as a Spice server and launch the default Spice client 1828 application. The Spice server will redirect the serial consoles 1829 and QEMU monitors. (Since 4.0) 1830ERST 1831 1832DEF("nographic", 0, QEMU_OPTION_nographic, 1833 "-nographic disable graphical output and redirect serial I/Os to console\n", 1834 QEMU_ARCH_ALL) 1835SRST 1836``-nographic`` 1837 Normally, if QEMU is compiled with graphical window support, it 1838 displays output such as guest graphics, guest console, and the QEMU 1839 monitor in a window. With this option, you can totally disable 1840 graphical output so that QEMU is a simple command line application. 1841 The emulated serial port is redirected on the console and muxed with 1842 the monitor (unless redirected elsewhere explicitly). Therefore, you 1843 can still use QEMU to debug a Linux kernel with a serial console. 1844 Use C-a h for help on switching between the console and monitor. 1845ERST 1846 1847DEF("curses", 0, QEMU_OPTION_curses, 1848 "-curses shorthand for -display curses\n", 1849 QEMU_ARCH_ALL) 1850SRST 1851``-curses`` 1852 Normally, if QEMU is compiled with graphical window support, it 1853 displays output such as guest graphics, guest console, and the QEMU 1854 monitor in a window. With this option, QEMU can display the VGA 1855 output when in text mode using a curses/ncurses interface. Nothing 1856 is displayed in graphical mode. 1857ERST 1858 1859DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1860 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1861 QEMU_ARCH_ALL) 1862SRST 1863``-alt-grab`` 1864 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1865 this also affects the special keys (for fullscreen, monitor-mode 1866 switching, etc). 1867ERST 1868 1869DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1870 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1871 QEMU_ARCH_ALL) 1872SRST 1873``-ctrl-grab`` 1874 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1875 also affects the special keys (for fullscreen, monitor-mode 1876 switching, etc). 1877ERST 1878 1879DEF("no-quit", 0, QEMU_OPTION_no_quit, 1880 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1881SRST 1882``-no-quit`` 1883 Disable SDL window close capability. 1884ERST 1885 1886DEF("sdl", 0, QEMU_OPTION_sdl, 1887 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1888SRST 1889``-sdl`` 1890 Enable SDL. 1891ERST 1892 1893DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1894 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1895 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1896 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1897 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1898 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1899 " [,tls-ciphers=<list>]\n" 1900 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1901 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1902 " [,sasl=on|off][,password=<secret>][,disable-ticketing=on|off]\n" 1903 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1904 " [,jpeg-wan-compression=[auto|never|always]]\n" 1905 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1906 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1907 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1908 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1909 " [,gl=[on|off]][,rendernode=<file>]\n" 1910 " enable spice\n" 1911 " at least one of {port, tls-port} is mandatory\n", 1912 QEMU_ARCH_ALL) 1913SRST 1914``-spice option[,option[,...]]`` 1915 Enable the spice remote desktop protocol. Valid options are 1916 1917 ``port=<nr>`` 1918 Set the TCP port spice is listening on for plaintext channels. 1919 1920 ``addr=<addr>`` 1921 Set the IP address spice is listening on. Default is any 1922 address. 1923 1924 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1925 Force using the specified IP version. 1926 1927 ``password=<secret>`` 1928 Set the password you need to authenticate. 1929 1930 ``sasl=on|off`` 1931 Require that the client use SASL to authenticate with the spice. 1932 The exact choice of authentication method used is controlled 1933 from the system / user's SASL configuration file for the 'qemu' 1934 service. This is typically found in /etc/sasl2/qemu.conf. If 1935 running QEMU as an unprivileged user, an environment variable 1936 SASL\_CONF\_PATH can be used to make it search alternate 1937 locations for the service config. While some SASL auth methods 1938 can also provide data encryption (eg GSSAPI), it is recommended 1939 that SASL always be combined with the 'tls' and 'x509' settings 1940 to enable use of SSL and server certificates. This ensures a 1941 data encryption preventing compromise of authentication 1942 credentials. 1943 1944 ``disable-ticketing=on|off`` 1945 Allow client connects without authentication. 1946 1947 ``disable-copy-paste=on|off`` 1948 Disable copy paste between the client and the guest. 1949 1950 ``disable-agent-file-xfer=on|off`` 1951 Disable spice-vdagent based file-xfer between the client and the 1952 guest. 1953 1954 ``tls-port=<nr>`` 1955 Set the TCP port spice is listening on for encrypted channels. 1956 1957 ``x509-dir=<dir>`` 1958 Set the x509 file directory. Expects same filenames as -vnc 1959 $display,x509=$dir 1960 1961 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 1962 The x509 file names can also be configured individually. 1963 1964 ``tls-ciphers=<list>`` 1965 Specify which ciphers to use. 1966 1967 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 1968 Force specific channel to be used with or without TLS 1969 encryption. The options can be specified multiple times to 1970 configure multiple channels. The special name "default" can be 1971 used to set the default mode. For channels which are not 1972 explicitly forced into one mode the spice client is allowed to 1973 pick tls/plaintext as he pleases. 1974 1975 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 1976 Configure image compression (lossless). Default is auto\_glz. 1977 1978 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 1979 Configure wan image compression (lossy for slow links). Default 1980 is auto. 1981 1982 ``streaming-video=[off|all|filter]`` 1983 Configure video stream detection. Default is off. 1984 1985 ``agent-mouse=[on|off]`` 1986 Enable/disable passing mouse events via vdagent. Default is on. 1987 1988 ``playback-compression=[on|off]`` 1989 Enable/disable audio stream compression (using celt 0.5.1). 1990 Default is on. 1991 1992 ``seamless-migration=[on|off]`` 1993 Enable/disable spice seamless migration. Default is off. 1994 1995 ``gl=[on|off]`` 1996 Enable/disable OpenGL context. Default is off. 1997 1998 ``rendernode=<file>`` 1999 DRM render node for OpenGL rendering. If not specified, it will 2000 pick the first available. (Since 2.9) 2001ERST 2002 2003DEF("portrait", 0, QEMU_OPTION_portrait, 2004 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2005 QEMU_ARCH_ALL) 2006SRST 2007``-portrait`` 2008 Rotate graphical output 90 deg left (only PXA LCD). 2009ERST 2010 2011DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2012 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2013 QEMU_ARCH_ALL) 2014SRST 2015``-rotate deg`` 2016 Rotate graphical output some deg left (only PXA LCD). 2017ERST 2018 2019DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2020 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2021 " select video card type\n", QEMU_ARCH_ALL) 2022SRST 2023``-vga type`` 2024 Select type of VGA card to emulate. Valid values for type are 2025 2026 ``cirrus`` 2027 Cirrus Logic GD5446 Video card. All Windows versions starting 2028 from Windows 95 should recognize and use this graphic card. For 2029 optimal performances, use 16 bit color depth in the guest and 2030 the host OS. (This card was the default before QEMU 2.2) 2031 2032 ``std`` 2033 Standard VGA card with Bochs VBE extensions. If your guest OS 2034 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2035 you want to use high resolution modes (>= 1280x1024x16) then you 2036 should use this option. (This card is the default since QEMU 2037 2.2) 2038 2039 ``vmware`` 2040 VMWare SVGA-II compatible adapter. Use it if you have 2041 sufficiently recent XFree86/XOrg server or Windows guest with a 2042 driver for this card. 2043 2044 ``qxl`` 2045 QXL paravirtual graphic card. It is VGA compatible (including 2046 VESA 2.0 VBE support). Works best with qxl guest drivers 2047 installed though. Recommended choice when using the spice 2048 protocol. 2049 2050 ``tcx`` 2051 (sun4m only) Sun TCX framebuffer. This is the default 2052 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2053 colour depths at a fixed resolution of 1024x768. 2054 2055 ``cg3`` 2056 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2057 framebuffer for sun4m machines available in both 1024x768 2058 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2059 wishing to run older Solaris versions. 2060 2061 ``virtio`` 2062 Virtio VGA card. 2063 2064 ``none`` 2065 Disable VGA card. 2066ERST 2067 2068DEF("full-screen", 0, QEMU_OPTION_full_screen, 2069 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2070SRST 2071``-full-screen`` 2072 Start in full screen. 2073ERST 2074 2075DEF("g", HAS_ARG, QEMU_OPTION_g , 2076 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2077 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2078SRST 2079``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2080 Set the initial graphical resolution and depth (PPC, SPARC only). 2081 2082 For PPC the default is 800x600x32. 2083 2084 For SPARC with the TCX graphics device, the default is 1024x768x8 2085 with the option of 1024x768x24. For cgthree, the default is 2086 1024x768x8 with the option of 1152x900x8 for people who wish to use 2087 OBP. 2088ERST 2089 2090DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2091 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2092SRST 2093``-vnc display[,option[,option[,...]]]`` 2094 Normally, if QEMU is compiled with graphical window support, it 2095 displays output such as guest graphics, guest console, and the QEMU 2096 monitor in a window. With this option, you can have QEMU listen on 2097 VNC display display and redirect the VGA display over the VNC 2098 session. It is very useful to enable the usb tablet device when 2099 using this option (option ``-device usb-tablet``). When using the 2100 VNC display, you must use the ``-k`` parameter to set the keyboard 2101 layout if you are not using en-us. Valid syntax for the display is 2102 2103 ``to=L`` 2104 With this option, QEMU will try next available VNC displays, 2105 until the number L, if the origianlly defined "-vnc display" is 2106 not available, e.g. port 5900+display is already used by another 2107 application. By default, to=0. 2108 2109 ``host:d`` 2110 TCP connections will only be allowed from host on display d. By 2111 convention the TCP port is 5900+d. Optionally, host can be 2112 omitted in which case the server will accept connections from 2113 any host. 2114 2115 ``unix:path`` 2116 Connections will be allowed over UNIX domain sockets where path 2117 is the location of a unix socket to listen for connections on. 2118 2119 ``none`` 2120 VNC is initialized but not started. The monitor ``change`` 2121 command can be used to later start the VNC server. 2122 2123 Following the display value there may be one or more option flags 2124 separated by commas. Valid options are 2125 2126 ``reverse=on|off`` 2127 Connect to a listening VNC client via a "reverse" connection. 2128 The client is specified by the display. For reverse network 2129 connections (host:d,``reverse``), the d argument is a TCP port 2130 number, not a display number. 2131 2132 ``websocket=on|off`` 2133 Opens an additional TCP listening port dedicated to VNC 2134 Websocket connections. If a bare websocket option is given, the 2135 Websocket port is 5700+display. An alternative port can be 2136 specified with the syntax ``websocket``\ =port. 2137 2138 If host is specified connections will only be allowed from this 2139 host. It is possible to control the websocket listen address 2140 independently, using the syntax ``websocket``\ =host:port. 2141 2142 If no TLS credentials are provided, the websocket connection 2143 runs in unencrypted mode. If TLS credentials are provided, the 2144 websocket connection requires encrypted client connections. 2145 2146 ``password=on|off`` 2147 Require that password based authentication is used for client 2148 connections. 2149 2150 The password must be set separately using the ``set_password`` 2151 command in the :ref:`QEMU monitor`. The 2152 syntax to change your password is: 2153 ``set_password <protocol> <password>`` where <protocol> could be 2154 either "vnc" or "spice". 2155 2156 If you would like to change <protocol> password expiration, you 2157 should use ``expire_password <protocol> <expiration-time>`` 2158 where expiration time could be one of the following options: 2159 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2160 make password expire in 60 seconds, or 1335196800 to make 2161 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2162 this date and time). 2163 2164 You can also use keywords "now" or "never" for the expiration 2165 time to allow <protocol> password to expire immediately or never 2166 expire. 2167 2168 ``tls-creds=ID`` 2169 Provides the ID of a set of TLS credentials to use to secure the 2170 VNC server. They will apply to both the normal VNC server socket 2171 and the websocket socket (if enabled). Setting TLS credentials 2172 will cause the VNC server socket to enable the VeNCrypt auth 2173 mechanism. The credentials should have been previously created 2174 using the ``-object tls-creds`` argument. 2175 2176 ``tls-authz=ID`` 2177 Provides the ID of the QAuthZ authorization object against which 2178 the client's x509 distinguished name will validated. This object 2179 is only resolved at time of use, so can be deleted and recreated 2180 on the fly while the VNC server is active. If missing, it will 2181 default to denying access. 2182 2183 ``sasl=on|off`` 2184 Require that the client use SASL to authenticate with the VNC 2185 server. The exact choice of authentication method used is 2186 controlled from the system / user's SASL configuration file for 2187 the 'qemu' service. This is typically found in 2188 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2189 an environment variable SASL\_CONF\_PATH can be used to make it 2190 search alternate locations for the service config. While some 2191 SASL auth methods can also provide data encryption (eg GSSAPI), 2192 it is recommended that SASL always be combined with the 'tls' 2193 and 'x509' settings to enable use of SSL and server 2194 certificates. This ensures a data encryption preventing 2195 compromise of authentication credentials. See the 2196 :ref:`VNC security` section in the System Emulation Users Guide 2197 for details on using SASL authentication. 2198 2199 ``sasl-authz=ID`` 2200 Provides the ID of the QAuthZ authorization object against which 2201 the client's SASL username will validated. This object is only 2202 resolved at time of use, so can be deleted and recreated on the 2203 fly while the VNC server is active. If missing, it will default 2204 to denying access. 2205 2206 ``acl=on|off`` 2207 Legacy method for enabling authorization of clients against the 2208 x509 distinguished name and SASL username. It results in the 2209 creation of two ``authz-list`` objects with IDs of 2210 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2211 objects must be configured with the HMP ACL commands. 2212 2213 This option is deprecated and should no longer be used. The new 2214 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2215 2216 ``lossy=on|off`` 2217 Enable lossy compression methods (gradient, JPEG, ...). If this 2218 option is set, VNC client may receive lossy framebuffer updates 2219 depending on its encoding settings. Enabling this option can 2220 save a lot of bandwidth at the expense of quality. 2221 2222 ``non-adaptive=on|off`` 2223 Disable adaptive encodings. Adaptive encodings are enabled by 2224 default. An adaptive encoding will try to detect frequently 2225 updated screen regions, and send updates in these regions using 2226 a lossy encoding (like JPEG). This can be really helpful to save 2227 bandwidth when playing videos. Disabling adaptive encodings 2228 restores the original static behavior of encodings like Tight. 2229 2230 ``share=[allow-exclusive|force-shared|ignore]`` 2231 Set display sharing policy. 'allow-exclusive' allows clients to 2232 ask for exclusive access. As suggested by the rfb spec this is 2233 implemented by dropping other connections. Connecting multiple 2234 clients in parallel requires all clients asking for a shared 2235 session (vncviewer: -shared switch). This is the default. 2236 'force-shared' disables exclusive client access. Useful for 2237 shared desktop sessions, where you don't want someone forgetting 2238 specify -shared disconnect everybody else. 'ignore' completely 2239 ignores the shared flag and allows everybody connect 2240 unconditionally. Doesn't conform to the rfb spec but is 2241 traditional QEMU behavior. 2242 2243 ``key-delay-ms`` 2244 Set keyboard delay, for key down and key up events, in 2245 milliseconds. Default is 10. Keyboards are low-bandwidth 2246 devices, so this slowdown can help the device and guest to keep 2247 up and not lose events in case events are arriving in bulk. 2248 Possible causes for the latter are flaky network connections, or 2249 scripts for automated testing. 2250 2251 ``audiodev=audiodev`` 2252 Use the specified audiodev when the VNC client requests audio 2253 transmission. When not using an -audiodev argument, this option 2254 must be omitted, otherwise is must be present and specify a 2255 valid audiodev. 2256 2257 ``power-control=on|off`` 2258 Permit the remote client to issue shutdown, reboot or reset power 2259 control requests. 2260ERST 2261 2262ARCHHEADING(, QEMU_ARCH_I386) 2263 2264ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2265 2266DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2267 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2268 QEMU_ARCH_I386) 2269SRST 2270``-win2k-hack`` 2271 Use it when installing Windows 2000 to avoid a disk full bug. After 2272 Windows 2000 is installed, you no longer need this option (this 2273 option slows down the IDE transfers). 2274ERST 2275 2276DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2277 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2278 QEMU_ARCH_I386) 2279SRST 2280``-no-fd-bootchk`` 2281 Disable boot signature checking for floppy disks in BIOS. May be 2282 needed to boot from old floppy disks. 2283ERST 2284 2285DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2286 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2287SRST 2288``-no-acpi`` 2289 Disable ACPI (Advanced Configuration and Power Interface) support. 2290 Use it if your guest OS complains about ACPI problems (PC target 2291 machine only). 2292ERST 2293 2294DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2295 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2296SRST 2297``-no-hpet`` 2298 Disable HPET support. 2299ERST 2300 2301DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2302 "-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" 2303 " ACPI table description\n", QEMU_ARCH_I386) 2304SRST 2305``-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]...]`` 2306 Add ACPI table with specified header fields and context from 2307 specified files. For file=, take whole ACPI table from the specified 2308 files, including all ACPI headers (possible overridden by other 2309 options). For data=, only data portion of the table is used, all 2310 header information is specified in the command line. If a SLIC table 2311 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2312 fields will override the same in the RSDT and the FADT (a.k.a. 2313 FACP), in order to ensure the field matches required by the 2314 Microsoft SLIC spec and the ACPI spec. 2315ERST 2316 2317DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2318 "-smbios file=binary\n" 2319 " load SMBIOS entry from binary file\n" 2320 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2321 " [,uefi=on|off]\n" 2322 " specify SMBIOS type 0 fields\n" 2323 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2324 " [,uuid=uuid][,sku=str][,family=str]\n" 2325 " specify SMBIOS type 1 fields\n" 2326 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2327 " [,asset=str][,location=str]\n" 2328 " specify SMBIOS type 2 fields\n" 2329 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2330 " [,sku=str]\n" 2331 " specify SMBIOS type 3 fields\n" 2332 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2333 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2334 " specify SMBIOS type 4 fields\n" 2335 "-smbios type=11[,value=str][,path=filename]\n" 2336 " specify SMBIOS type 11 fields\n" 2337 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2338 " [,asset=str][,part=str][,speed=%d]\n" 2339 " specify SMBIOS type 17 fields\n", 2340 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2341SRST 2342``-smbios file=binary`` 2343 Load SMBIOS entry from binary file. 2344 2345``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2346 Specify SMBIOS type 0 fields 2347 2348``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2349 Specify SMBIOS type 1 fields 2350 2351``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2352 Specify SMBIOS type 2 fields 2353 2354``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2355 Specify SMBIOS type 3 fields 2356 2357``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2358 Specify SMBIOS type 4 fields 2359 2360``-smbios type=11[,value=str][,path=filename]`` 2361 Specify SMBIOS type 11 fields 2362 2363 This argument can be repeated multiple times, and values are added in the order they are parsed. 2364 Applications intending to use OEM strings data are encouraged to use their application name as 2365 a prefix for the value string. This facilitates passing information for multiple applications 2366 concurrently. 2367 2368 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2369 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2370 2371 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2372 the SMBIOS table in the order in which they appear. 2373 2374 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2375 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2376 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2377 data set, for example, by specifying the serial ID of a block device. 2378 2379 An example passing three strings is 2380 2381 .. parsed-literal:: 2382 2383 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2384 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2385 path=/some/file/with/oemstringsdata.txt 2386 2387 In the guest OS this is visible with the ``dmidecode`` command 2388 2389 .. parsed-literal:: 2390 2391 $ dmidecode -t 11 2392 Handle 0x0E00, DMI type 11, 5 bytes 2393 OEM Strings 2394 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2395 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2396 String 3: myapp:some extra data 2397 2398 2399``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2400 Specify SMBIOS type 17 fields 2401ERST 2402 2403DEFHEADING() 2404 2405DEFHEADING(Network options:) 2406 2407DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2408#ifdef CONFIG_SLIRP 2409 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2410 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2411 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2412 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2413 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2414#ifndef _WIN32 2415 "[,smb=dir[,smbserver=addr]]\n" 2416#endif 2417 " configure a user mode network backend with ID 'str',\n" 2418 " its DHCP server and optional services\n" 2419#endif 2420#ifdef _WIN32 2421 "-netdev tap,id=str,ifname=name\n" 2422 " configure a host TAP network backend with ID 'str'\n" 2423#else 2424 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2425 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2426 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2427 " [,poll-us=n]\n" 2428 " configure a host TAP network backend with ID 'str'\n" 2429 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2430 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2431 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2432 " to deconfigure it\n" 2433 " use '[down]script=no' to disable script execution\n" 2434 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2435 " configure it\n" 2436 " use 'fd=h' to connect to an already opened TAP interface\n" 2437 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2438 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2439 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2440 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2441 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2442 " use vhost=on to enable experimental in kernel accelerator\n" 2443 " (only has effect for virtio guests which use MSIX)\n" 2444 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2445 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2446 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2447 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2448 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2449 " spent on busy polling for vhost net\n" 2450 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2451 " configure a host TAP network backend with ID 'str' that is\n" 2452 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2453 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2454#endif 2455#ifdef __linux__ 2456 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2457 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2458 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2459 " [,rxcookie=rxcookie][,offset=offset]\n" 2460 " configure a network backend with ID 'str' connected to\n" 2461 " an Ethernet over L2TPv3 pseudowire.\n" 2462 " Linux kernel 3.3+ as well as most routers can talk\n" 2463 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2464 " VM to a router and even VM to Host. It is a nearly-universal\n" 2465 " standard (RFC3931). Note - this implementation uses static\n" 2466 " pre-configured tunnels (same as the Linux kernel).\n" 2467 " use 'src=' to specify source address\n" 2468 " use 'dst=' to specify destination address\n" 2469 " use 'udp=on' to specify udp encapsulation\n" 2470 " use 'srcport=' to specify source udp port\n" 2471 " use 'dstport=' to specify destination udp port\n" 2472 " use 'ipv6=on' to force v6\n" 2473 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2474 " well as a weak security measure\n" 2475 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2476 " use 'txcookie=0x012345678' to specify a txcookie\n" 2477 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2478 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2479 " use 'pincounter=on' to work around broken counter handling in peer\n" 2480 " use 'offset=X' to add an extra offset between header and data\n" 2481#endif 2482 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2483 " configure a network backend to connect to another network\n" 2484 " using a socket connection\n" 2485 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2486 " configure a network backend to connect to a multicast maddr and port\n" 2487 " use 'localaddr=addr' to specify the host address to send packets from\n" 2488 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2489 " configure a network backend to connect to another network\n" 2490 " using an UDP tunnel\n" 2491#ifdef CONFIG_VDE 2492 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2493 " configure a network backend to connect to port 'n' of a vde switch\n" 2494 " running on host and listening for incoming connections on 'socketpath'.\n" 2495 " Use group 'groupname' and mode 'octalmode' to change default\n" 2496 " ownership and permissions for communication port.\n" 2497#endif 2498#ifdef CONFIG_NETMAP 2499 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2500 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2501 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2502 " netmap device, defaults to '/dev/netmap')\n" 2503#endif 2504#ifdef CONFIG_POSIX 2505 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2506 " configure a vhost-user network, backed by a chardev 'dev'\n" 2507#endif 2508#ifdef __linux__ 2509 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2510 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2511#endif 2512 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2513 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2514DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2515 "-nic [tap|bridge|" 2516#ifdef CONFIG_SLIRP 2517 "user|" 2518#endif 2519#ifdef __linux__ 2520 "l2tpv3|" 2521#endif 2522#ifdef CONFIG_VDE 2523 "vde|" 2524#endif 2525#ifdef CONFIG_NETMAP 2526 "netmap|" 2527#endif 2528#ifdef CONFIG_POSIX 2529 "vhost-user|" 2530#endif 2531 "socket][,option][,...][mac=macaddr]\n" 2532 " initialize an on-board / default host NIC (using MAC address\n" 2533 " macaddr) and connect it to the given host network backend\n" 2534 "-nic none use it alone to have zero network devices (the default is to\n" 2535 " provided a 'user' network connection)\n", 2536 QEMU_ARCH_ALL) 2537DEF("net", HAS_ARG, QEMU_OPTION_net, 2538 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2539 " configure or create an on-board (or machine default) NIC and\n" 2540 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2541 "-net [" 2542#ifdef CONFIG_SLIRP 2543 "user|" 2544#endif 2545 "tap|" 2546 "bridge|" 2547#ifdef CONFIG_VDE 2548 "vde|" 2549#endif 2550#ifdef CONFIG_NETMAP 2551 "netmap|" 2552#endif 2553 "socket][,option][,option][,...]\n" 2554 " old way to initialize a host network interface\n" 2555 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2556SRST 2557``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2558 This option is a shortcut for configuring both the on-board 2559 (default) guest NIC hardware and the host network backend in one go. 2560 The host backend options are the same as with the corresponding 2561 ``-netdev`` options below. The guest NIC model can be set with 2562 ``model=modelname``. Use ``model=help`` to list the available device 2563 types. The hardware MAC address can be set with ``mac=macaddr``. 2564 2565 The following two example do exactly the same, to show how ``-nic`` 2566 can be used to shorten the command line length: 2567 2568 .. parsed-literal:: 2569 2570 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2571 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2572 2573``-nic none`` 2574 Indicate that no network devices should be configured. It is used to 2575 override the default configuration (default NIC with "user" host 2576 network backend) which is activated if no other networking options 2577 are provided. 2578 2579``-netdev user,id=id[,option][,option][,...]`` 2580 Configure user mode host network backend which requires no 2581 administrator privilege to run. Valid options are: 2582 2583 ``id=id`` 2584 Assign symbolic name for use in monitor commands. 2585 2586 ``ipv4=on|off and ipv6=on|off`` 2587 Specify that either IPv4 or IPv6 must be enabled. If neither is 2588 specified both protocols are enabled. 2589 2590 ``net=addr[/mask]`` 2591 Set IP network address the guest will see. Optionally specify 2592 the netmask, either in the form a.b.c.d or as number of valid 2593 top-most bits. Default is 10.0.2.0/24. 2594 2595 ``host=addr`` 2596 Specify the guest-visible address of the host. Default is the 2597 2nd IP in the guest network, i.e. x.x.x.2. 2598 2599 ``ipv6-net=addr[/int]`` 2600 Set IPv6 network address the guest will see (default is 2601 fec0::/64). The network prefix is given in the usual hexadecimal 2602 IPv6 address notation. The prefix size is optional, and is given 2603 as the number of valid top-most bits (default is 64). 2604 2605 ``ipv6-host=addr`` 2606 Specify the guest-visible IPv6 address of the host. Default is 2607 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2608 2609 ``restrict=on|off`` 2610 If this option is enabled, the guest will be isolated, i.e. it 2611 will not be able to contact the host and no guest IP packets 2612 will be routed over the host to the outside. This option does 2613 not affect any explicitly set forwarding rules. 2614 2615 ``hostname=name`` 2616 Specifies the client hostname reported by the built-in DHCP 2617 server. 2618 2619 ``dhcpstart=addr`` 2620 Specify the first of the 16 IPs the built-in DHCP server can 2621 assign. Default is the 15th to 31st IP in the guest network, 2622 i.e. x.x.x.15 to x.x.x.31. 2623 2624 ``dns=addr`` 2625 Specify the guest-visible address of the virtual nameserver. The 2626 address must be different from the host address. Default is the 2627 3rd IP in the guest network, i.e. x.x.x.3. 2628 2629 ``ipv6-dns=addr`` 2630 Specify the guest-visible address of the IPv6 virtual 2631 nameserver. The address must be different from the host address. 2632 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2633 2634 ``dnssearch=domain`` 2635 Provides an entry for the domain-search list sent by the 2636 built-in DHCP server. More than one domain suffix can be 2637 transmitted by specifying this option multiple times. If 2638 supported, this will cause the guest to automatically try to 2639 append the given domain suffix(es) in case a domain name can not 2640 be resolved. 2641 2642 Example: 2643 2644 .. parsed-literal:: 2645 2646 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2647 2648 ``domainname=domain`` 2649 Specifies the client domain name reported by the built-in DHCP 2650 server. 2651 2652 ``tftp=dir`` 2653 When using the user mode network stack, activate a built-in TFTP 2654 server. The files in dir will be exposed as the root of a TFTP 2655 server. The TFTP client on the guest must be configured in 2656 binary mode (use the command ``bin`` of the Unix TFTP client). 2657 2658 ``tftp-server-name=name`` 2659 In BOOTP reply, broadcast name as the "TFTP server name" 2660 (RFC2132 option 66). This can be used to advise the guest to 2661 load boot files or configurations from a different server than 2662 the host address. 2663 2664 ``bootfile=file`` 2665 When using the user mode network stack, broadcast file as the 2666 BOOTP filename. In conjunction with ``tftp``, this can be used 2667 to network boot a guest from a local directory. 2668 2669 Example (using pxelinux): 2670 2671 .. parsed-literal:: 2672 2673 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2674 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2675 2676 ``smb=dir[,smbserver=addr]`` 2677 When using the user mode network stack, activate a built-in SMB 2678 server so that Windows OSes can access to the host files in 2679 ``dir`` transparently. The IP address of the SMB server can be 2680 set to addr. By default the 4th IP in the guest network is used, 2681 i.e. x.x.x.4. 2682 2683 In the guest Windows OS, the line: 2684 2685 :: 2686 2687 10.0.2.4 smbserver 2688 2689 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2690 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2691 NT/2000). 2692 2693 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2694 2695 Note that a SAMBA server must be installed on the host OS. 2696 2697 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2698 Redirect incoming TCP or UDP connections to the host port 2699 hostport to the guest IP address guestaddr on guest port 2700 guestport. If guestaddr is not specified, its value is x.x.x.15 2701 (default first address given by the built-in DHCP server). By 2702 specifying hostaddr, the rule can be bound to a specific host 2703 interface. If no connection type is set, TCP is used. This 2704 option can be given multiple times. 2705 2706 For example, to redirect host X11 connection from screen 1 to 2707 guest screen 0, use the following: 2708 2709 .. parsed-literal:: 2710 2711 # on the host 2712 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2713 # this host xterm should open in the guest X11 server 2714 xterm -display :1 2715 2716 To redirect telnet connections from host port 5555 to telnet 2717 port on the guest, use the following: 2718 2719 .. parsed-literal:: 2720 2721 # on the host 2722 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2723 telnet localhost 5555 2724 2725 Then when you use on the host ``telnet localhost 5555``, you 2726 connect to the guest telnet server. 2727 2728 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2729 Forward guest TCP connections to the IP address server on port 2730 port to the character device dev or to a program executed by 2731 cmd:command which gets spawned for each connection. This option 2732 can be given multiple times. 2733 2734 You can either use a chardev directly and have that one used 2735 throughout QEMU's lifetime, like in the following example: 2736 2737 .. parsed-literal:: 2738 2739 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2740 # the guest accesses it 2741 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2742 2743 Or you can execute a command on every TCP connection established 2744 by the guest, so that QEMU behaves similar to an inetd process 2745 for that virtual server: 2746 2747 .. parsed-literal:: 2748 2749 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2750 # and connect the TCP stream to its stdin/stdout 2751 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2752 2753``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2754 Configure a host TAP network backend with ID id. 2755 2756 Use the network script file to configure it and the network script 2757 dfile to deconfigure it. If name is not provided, the OS 2758 automatically provides one. The default network configure script is 2759 ``/etc/qemu-ifup`` and the default network deconfigure script is 2760 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2761 disable script execution. 2762 2763 If running QEMU as an unprivileged user, use the network helper 2764 to configure the TAP interface and attach it to the bridge. 2765 The default network helper executable is 2766 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2767 ``br0``. 2768 2769 ``fd``\ =h can be used to specify the handle of an already opened 2770 host TAP interface. 2771 2772 Examples: 2773 2774 .. parsed-literal:: 2775 2776 #launch a QEMU instance with the default network script 2777 |qemu_system| linux.img -nic tap 2778 2779 .. parsed-literal:: 2780 2781 #launch a QEMU instance with two NICs, each one connected 2782 #to a TAP device 2783 |qemu_system| linux.img \\ 2784 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2785 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2786 2787 .. parsed-literal:: 2788 2789 #launch a QEMU instance with the default network helper to 2790 #connect a TAP device to bridge br0 2791 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2792 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2793 2794``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2795 Connect a host TAP network interface to a host bridge device. 2796 2797 Use the network helper helper to configure the TAP interface and 2798 attach it to the bridge. The default network helper executable is 2799 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2800 ``br0``. 2801 2802 Examples: 2803 2804 .. parsed-literal:: 2805 2806 #launch a QEMU instance with the default network helper to 2807 #connect a TAP device to bridge br0 2808 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2809 2810 .. parsed-literal:: 2811 2812 #launch a QEMU instance with the default network helper to 2813 #connect a TAP device to bridge qemubr0 2814 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2815 2816``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2817 This host network backend can be used to connect the guest's network 2818 to another QEMU virtual machine using a TCP socket connection. If 2819 ``listen`` is specified, QEMU waits for incoming connections on port 2820 (host is optional). ``connect`` is used to connect to another QEMU 2821 instance using the ``listen`` option. ``fd``\ =h specifies an 2822 already opened TCP socket. 2823 2824 Example: 2825 2826 .. parsed-literal:: 2827 2828 # launch a first QEMU instance 2829 |qemu_system| linux.img \\ 2830 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2831 -netdev socket,id=n1,listen=:1234 2832 # connect the network of this instance to the network of the first instance 2833 |qemu_system| linux.img \\ 2834 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2835 -netdev socket,id=n2,connect=127.0.0.1:1234 2836 2837``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2838 Configure a socket host network backend to share the guest's network 2839 traffic with another QEMU virtual machines using a UDP multicast 2840 socket, effectively making a bus for every QEMU with same multicast 2841 address maddr and port. NOTES: 2842 2843 1. Several QEMU can be running on different hosts and share same bus 2844 (assuming correct multicast setup for these hosts). 2845 2846 2. mcast support is compatible with User Mode Linux (argument 2847 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2848 2849 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2850 2851 Example: 2852 2853 .. parsed-literal:: 2854 2855 # launch one QEMU instance 2856 |qemu_system| linux.img \\ 2857 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2858 -netdev socket,id=n1,mcast=230.0.0.1:1234 2859 # launch another QEMU instance on same "bus" 2860 |qemu_system| linux.img \\ 2861 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2862 -netdev socket,id=n2,mcast=230.0.0.1:1234 2863 # launch yet another QEMU instance on same "bus" 2864 |qemu_system| linux.img \\ 2865 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2866 -netdev socket,id=n3,mcast=230.0.0.1:1234 2867 2868 Example (User Mode Linux compat.): 2869 2870 .. parsed-literal:: 2871 2872 # launch QEMU instance (note mcast address selected is UML's default) 2873 |qemu_system| linux.img \\ 2874 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2875 -netdev socket,id=n1,mcast=239.192.168.1:1102 2876 # launch UML 2877 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2878 2879 Example (send packets from host's 1.2.3.4): 2880 2881 .. parsed-literal:: 2882 2883 |qemu_system| linux.img \\ 2884 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2885 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2886 2887``-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]`` 2888 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2889 is a popular protocol to transport Ethernet (and other Layer 2) data 2890 frames between two systems. It is present in routers, firewalls and 2891 the Linux kernel (from version 3.3 onwards). 2892 2893 This transport allows a VM to communicate to another VM, router or 2894 firewall directly. 2895 2896 ``src=srcaddr`` 2897 source address (mandatory) 2898 2899 ``dst=dstaddr`` 2900 destination address (mandatory) 2901 2902 ``udp`` 2903 select udp encapsulation (default is ip). 2904 2905 ``srcport=srcport`` 2906 source udp port. 2907 2908 ``dstport=dstport`` 2909 destination udp port. 2910 2911 ``ipv6`` 2912 force v6, otherwise defaults to v4. 2913 2914 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2915 Cookies are a weak form of security in the l2tpv3 specification. 2916 Their function is mostly to prevent misconfiguration. By default 2917 they are 32 bit. 2918 2919 ``cookie64`` 2920 Set cookie size to 64 bit instead of the default 32 2921 2922 ``counter=off`` 2923 Force a 'cut-down' L2TPv3 with no counter as in 2924 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2925 2926 ``pincounter=on`` 2927 Work around broken counter handling in peer. This may also help 2928 on networks which have packet reorder. 2929 2930 ``offset=offset`` 2931 Add an extra offset between header and data 2932 2933 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 2934 the bridge br-lan on the remote Linux host 1.2.3.4: 2935 2936 .. parsed-literal:: 2937 2938 # Setup tunnel on linux host using raw ip as encapsulation 2939 # on 1.2.3.4 2940 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 2941 encap udp udp_sport 16384 udp_dport 16384 2942 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 2943 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2944 ifconfig vmtunnel0 mtu 1500 2945 ifconfig vmtunnel0 up 2946 brctl addif br-lan vmtunnel0 2947 2948 2949 # on 4.3.2.1 2950 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2951 2952 |qemu_system| linux.img -device e1000,netdev=n1 \\ 2953 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2954 2955``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 2956 Configure VDE backend to connect to PORT n of a vde switch running 2957 on host and listening for incoming connections on socketpath. Use 2958 GROUP groupname and MODE octalmode to change default ownership and 2959 permissions for communication port. This option is only available if 2960 QEMU has been compiled with vde support enabled. 2961 2962 Example: 2963 2964 .. parsed-literal:: 2965 2966 # launch vde switch 2967 vde_switch -F -sock /tmp/myswitch 2968 # launch QEMU instance 2969 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 2970 2971``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 2972 Establish a vhost-user netdev, backed by a chardev id. The chardev 2973 should be a unix domain socket backed one. The vhost-user uses a 2974 specifically defined protocol to pass vhost ioctl replacement 2975 messages to an application on the other end of the socket. On 2976 non-MSIX guests, the feature can be forced with vhostforce. Use 2977 'queues=n' to specify the number of queues to be created for 2978 multiqueue vhost-user. 2979 2980 Example: 2981 2982 :: 2983 2984 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 2985 -numa node,memdev=mem \ 2986 -chardev socket,id=chr0,path=/path/to/socket \ 2987 -netdev type=vhost-user,id=net0,chardev=chr0 \ 2988 -device virtio-net-pci,netdev=net0 2989 2990``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 2991 Establish a vhost-vdpa netdev. 2992 2993 vDPA device is a device that uses a datapath which complies with 2994 the virtio specifications with a vendor specific control path. 2995 vDPA devices can be both physically located on the hardware or 2996 emulated by software. 2997 2998``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 2999 Create a hub port on the emulated hub with ID hubid. 3000 3001 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3002 instead of a single netdev. Alternatively, you can also connect the 3003 hubport to another netdev with ID nd by using the ``netdev=nd`` 3004 option. 3005 3006``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3007 Legacy option to configure or create an on-board (or machine 3008 default) Network Interface Card(NIC) and connect it either to the 3009 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3010 If model is omitted, then the default NIC model associated with the 3011 machine type is used. Note that the default NIC model may change in 3012 future QEMU releases, so it is highly recommended to always specify 3013 a model. Optionally, the MAC address can be changed to mac, the 3014 device address set to addr (PCI cards only), and a name can be 3015 assigned for use in monitor commands. Optionally, for PCI cards, you 3016 can specify the number v of MSI-X vectors that the card should have; 3017 this option currently only affects virtio cards; set v = 0 to 3018 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3019 created. QEMU can emulate several different models of network card. 3020 Use ``-net nic,model=help`` for a list of available devices for your 3021 target. 3022 3023``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3024 Configure a host network backend (with the options corresponding to 3025 the same ``-netdev`` option) and connect it to the emulated hub 0 3026 (the default hub). Use name to specify the name of the hub port. 3027ERST 3028 3029DEFHEADING() 3030 3031DEFHEADING(Character device options:) 3032 3033DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3034 "-chardev help\n" 3035 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3036 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3037 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3038 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3039 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3040 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3041 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3042 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3043 " [,logfile=PATH][,logappend=on|off]\n" 3044 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3045 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3046 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3047 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3048 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3049 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3050#ifdef _WIN32 3051 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3052 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3053#else 3054 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3055 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3056#endif 3057#ifdef CONFIG_BRLAPI 3058 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3059#endif 3060#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3061 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3062 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3063 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3064#endif 3065#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3066 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3067 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3068#endif 3069#if defined(CONFIG_SPICE) 3070 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3071 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3072#endif 3073 , QEMU_ARCH_ALL 3074) 3075 3076SRST 3077The general form of a character device option is: 3078 3079``-chardev backend,id=id[,mux=on|off][,options]`` 3080 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3081 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3082 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3083 ``spicevmc``, ``spiceport``. The specific backend will determine the 3084 applicable options. 3085 3086 Use ``-chardev help`` to print all available chardev backend types. 3087 3088 All devices must have an id, which can be any string up to 127 3089 characters long. It is used to uniquely identify this device in 3090 other command line directives. 3091 3092 A character device may be used in multiplexing mode by multiple 3093 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3094 a "1:N" device, and here the "1" end is your specified chardev 3095 backend, and the "N" end is the various parts of QEMU that can talk 3096 to a chardev. If you create a chardev with ``id=myid`` and 3097 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3098 and you can then configure multiple front ends to use that chardev 3099 ID for their input/output. Up to four different front ends can be 3100 connected to a single multiplexed chardev. (Without multiplexing 3101 enabled, a chardev can only be used by a single front end.) For 3102 instance you could use this to allow a single stdio chardev to be 3103 used by two serial ports and the QEMU monitor: 3104 3105 :: 3106 3107 -chardev stdio,mux=on,id=char0 \ 3108 -mon chardev=char0,mode=readline \ 3109 -serial chardev:char0 \ 3110 -serial chardev:char0 3111 3112 You can have more than one multiplexer in a system configuration; 3113 for instance you could have a TCP port multiplexed between UART 0 3114 and UART 1, and stdio multiplexed between the QEMU monitor and a 3115 parallel port: 3116 3117 :: 3118 3119 -chardev stdio,mux=on,id=char0 \ 3120 -mon chardev=char0,mode=readline \ 3121 -parallel chardev:char0 \ 3122 -chardev tcp,...,mux=on,id=char1 \ 3123 -serial chardev:char1 \ 3124 -serial chardev:char1 3125 3126 When you're using a multiplexed character device, some escape 3127 sequences are interpreted in the input. See the chapter about 3128 :ref:`keys in the character backend multiplexer` in the 3129 System Emulation Users Guide for more details. 3130 3131 Note that some other command line options may implicitly create 3132 multiplexed character backends; for instance ``-serial mon:stdio`` 3133 creates a multiplexed stdio backend connected to the serial port and 3134 the QEMU monitor, and ``-nographic`` also multiplexes the console 3135 and the monitor to stdio. 3136 3137 There is currently no support for multiplexing in the other 3138 direction (where a single QEMU front end takes input and output from 3139 multiple chardevs). 3140 3141 Every backend supports the ``logfile`` option, which supplies the 3142 path to a file to record all data transmitted via the backend. The 3143 ``logappend`` option controls whether the log file will be truncated 3144 or appended to when opened. 3145 3146The available backends are: 3147 3148``-chardev null,id=id`` 3149 A void device. This device will not emit any data, and will drop any 3150 data it receives. The null backend does not take any options. 3151 3152``-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]`` 3153 Create a two-way stream socket, which can be either a TCP or a unix 3154 socket. A unix socket will be created if ``path`` is specified. 3155 Behaviour is undefined if TCP options are specified for a unix 3156 socket. 3157 3158 ``server=on|off`` specifies that the socket shall be a listening socket. 3159 3160 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3161 to connect to a listening socket. 3162 3163 ``telnet=on|off`` specifies that traffic on the socket should interpret 3164 telnet escape sequences. 3165 3166 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3167 communication. 3168 3169 ``reconnect`` sets the timeout for reconnecting on non-server 3170 sockets when the remote end goes away. qemu will delay this many 3171 seconds and then attempt to reconnect. Zero disables reconnecting, 3172 and is the default. 3173 3174 ``tls-creds`` requests enablement of the TLS protocol for 3175 encryption, and specifies the id of the TLS credentials to use for 3176 the handshake. The credentials must be previously created with the 3177 ``-object tls-creds`` argument. 3178 3179 ``tls-auth`` provides the ID of the QAuthZ authorization object 3180 against which the client's x509 distinguished name will be 3181 validated. This object is only resolved at time of use, so can be 3182 deleted and recreated on the fly while the chardev server is active. 3183 If missing, it will default to denying access. 3184 3185 TCP and unix socket options are given below: 3186 3187 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3188 ``host`` for a listening socket specifies the local address to 3189 be bound. For a connecting socket species the remote host to 3190 connect to. ``host`` is optional for listening sockets. If not 3191 specified it defaults to ``0.0.0.0``. 3192 3193 ``port`` for a listening socket specifies the local port to be 3194 bound. For a connecting socket specifies the port on the remote 3195 host to connect to. ``port`` can be given as either a port 3196 number or a service name. ``port`` is required. 3197 3198 ``to`` is only relevant to listening sockets. If it is 3199 specified, and ``port`` cannot be bound, QEMU will attempt to 3200 bind to subsequent ports up to and including ``to`` until it 3201 succeeds. ``to`` must be specified as a port number. 3202 3203 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3204 or IPv6 must be used. If neither is specified the socket may 3205 use either protocol. 3206 3207 ``nodelay=on|off`` disables the Nagle algorithm. 3208 3209 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3210 ``path`` specifies the local path of the unix socket. ``path`` 3211 is required. 3212 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3213 rather than the filesystem. Optional, defaults to false. 3214 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3215 rather than the full sun_path length. Optional, defaults to true. 3216 3217``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3218 Sends all traffic from the guest to a remote host over UDP. 3219 3220 ``host`` specifies the remote host to connect to. If not specified 3221 it defaults to ``localhost``. 3222 3223 ``port`` specifies the port on the remote host to connect to. 3224 ``port`` is required. 3225 3226 ``localaddr`` specifies the local address to bind to. If not 3227 specified it defaults to ``0.0.0.0``. 3228 3229 ``localport`` specifies the local port to bind to. If not specified 3230 any available local port will be used. 3231 3232 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3233 If neither is specified the device may use either protocol. 3234 3235``-chardev msmouse,id=id`` 3236 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3237 does not take any options. 3238 3239``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3240 Connect to a QEMU text console. ``vc`` may optionally be given a 3241 specific size. 3242 3243 ``width`` and ``height`` specify the width and height respectively 3244 of the console, in pixels. 3245 3246 ``cols`` and ``rows`` specify that the console be sized to fit a 3247 text console with the given dimensions. 3248 3249``-chardev ringbuf,id=id[,size=size]`` 3250 Create a ring buffer with fixed size ``size``. size must be a power 3251 of two and defaults to ``64K``. 3252 3253``-chardev file,id=id,path=path`` 3254 Log all traffic received from the guest to a file. 3255 3256 ``path`` specifies the path of the file to be opened. This file will 3257 be created if it does not already exist, and overwritten if it does. 3258 ``path`` is required. 3259 3260``-chardev pipe,id=id,path=path`` 3261 Create a two-way connection to the guest. The behaviour differs 3262 slightly between Windows hosts and other hosts: 3263 3264 On Windows, a single duplex pipe will be created at 3265 ``\\.pipe\path``. 3266 3267 On other hosts, 2 pipes will be created called ``path.in`` and 3268 ``path.out``. Data written to ``path.in`` will be received by the 3269 guest. Data written by the guest can be read from ``path.out``. QEMU 3270 will not create these fifos, and requires them to be present. 3271 3272 ``path`` forms part of the pipe path as described above. ``path`` is 3273 required. 3274 3275``-chardev console,id=id`` 3276 Send traffic from the guest to QEMU's standard output. ``console`` 3277 does not take any options. 3278 3279 ``console`` is only available on Windows hosts. 3280 3281``-chardev serial,id=id,path=path`` 3282 Send traffic from the guest to a serial device on the host. 3283 3284 On Unix hosts serial will actually accept any tty device, not only 3285 serial lines. 3286 3287 ``path`` specifies the name of the serial device to open. 3288 3289``-chardev pty,id=id`` 3290 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3291 does not take any options. 3292 3293 ``pty`` is not available on Windows hosts. 3294 3295``-chardev stdio,id=id[,signal=on|off]`` 3296 Connect to standard input and standard output of the QEMU process. 3297 3298 ``signal`` controls if signals are enabled on the terminal, that 3299 includes exiting QEMU with the key sequence Control-c. This option 3300 is enabled by default, use ``signal=off`` to disable it. 3301 3302``-chardev braille,id=id`` 3303 Connect to a local BrlAPI server. ``braille`` does not take any 3304 options. 3305 3306``-chardev tty,id=id,path=path`` 3307 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3308 and DragonFlyBSD hosts. It is an alias for ``serial``. 3309 3310 ``path`` specifies the path to the tty. ``path`` is required. 3311 3312``-chardev parallel,id=id,path=path`` 3313 \ 3314``-chardev parport,id=id,path=path`` 3315 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3316 hosts. 3317 3318 Connect to a local parallel port. 3319 3320 ``path`` specifies the path to the parallel port device. ``path`` is 3321 required. 3322 3323``-chardev spicevmc,id=id,debug=debug,name=name`` 3324 ``spicevmc`` is only available when spice support is built in. 3325 3326 ``debug`` debug level for spicevmc 3327 3328 ``name`` name of spice channel to connect to 3329 3330 Connect to a spice virtual machine channel, such as vdiport. 3331 3332``-chardev spiceport,id=id,debug=debug,name=name`` 3333 ``spiceport`` is only available when spice support is built in. 3334 3335 ``debug`` debug level for spicevmc 3336 3337 ``name`` name of spice port to connect to 3338 3339 Connect to a spice port, allowing a Spice client to handle the 3340 traffic identified by a name (preferably a fqdn). 3341ERST 3342 3343DEFHEADING() 3344 3345#ifdef CONFIG_TPM 3346DEFHEADING(TPM device options:) 3347 3348DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3349 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3350 " use path to provide path to a character device; default is /dev/tpm0\n" 3351 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3352 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3353 "-tpmdev emulator,id=id,chardev=dev\n" 3354 " configure the TPM device using chardev backend\n", 3355 QEMU_ARCH_ALL) 3356SRST 3357The general form of a TPM device option is: 3358 3359``-tpmdev backend,id=id[,options]`` 3360 The specific backend type will determine the applicable options. The 3361 ``-tpmdev`` option creates the TPM backend and requires a 3362 ``-device`` option that specifies the TPM frontend interface model. 3363 3364 Use ``-tpmdev help`` to print all available TPM backend types. 3365 3366The available backends are: 3367 3368``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3369 (Linux-host only) Enable access to the host's TPM using the 3370 passthrough driver. 3371 3372 ``path`` specifies the path to the host's TPM device, i.e., on a 3373 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3374 default ``/dev/tpm0`` is used. 3375 3376 ``cancel-path`` specifies the path to the host TPM device's sysfs 3377 entry allowing for cancellation of an ongoing TPM command. 3378 ``cancel-path`` is optional and by default QEMU will search for the 3379 sysfs entry to use. 3380 3381 Some notes about using the host's TPM with the passthrough driver: 3382 3383 The TPM device accessed by the passthrough driver must not be used 3384 by any other application on the host. 3385 3386 Since the host's firmware (BIOS/UEFI) has already initialized the 3387 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3388 the TPM again and may therefore not show a TPM-specific menu that 3389 would otherwise allow the user to configure the TPM, e.g., allow the 3390 user to enable/disable or activate/deactivate the TPM. Further, if 3391 TPM ownership is released from within a VM then the host's TPM will 3392 get disabled and deactivated. To enable and activate the TPM again 3393 afterwards, the host has to be rebooted and the user is required to 3394 enter the firmware's menu to enable and activate the TPM. If the TPM 3395 is left disabled and/or deactivated most TPM commands will fail. 3396 3397 To create a passthrough TPM use the following two options: 3398 3399 :: 3400 3401 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3402 3403 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3404 ``tpmdev=tpm0`` in the device option. 3405 3406``-tpmdev emulator,id=id,chardev=dev`` 3407 (Linux-host only) Enable access to a TPM emulator using Unix domain 3408 socket based chardev backend. 3409 3410 ``chardev`` specifies the unique ID of a character device backend 3411 that provides connection to the software TPM server. 3412 3413 To create a TPM emulator backend device with chardev socket backend: 3414 3415 :: 3416 3417 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3418ERST 3419 3420DEFHEADING() 3421 3422#endif 3423 3424DEFHEADING(Linux/Multiboot boot specific:) 3425SRST 3426When using these options, you can use a given Linux or Multiboot kernel 3427without installing it in the disk image. It can be useful for easier 3428testing of various kernels. 3429 3430 3431ERST 3432 3433DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3434 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3435SRST 3436``-kernel bzImage`` 3437 Use bzImage as kernel image. The kernel can be either a Linux kernel 3438 or in multiboot format. 3439ERST 3440 3441DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3442 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3443SRST 3444``-append cmdline`` 3445 Use cmdline as kernel command line 3446ERST 3447 3448DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3449 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3450SRST 3451``-initrd file`` 3452 Use file as initial ram disk. 3453 3454``-initrd "file1 arg=foo,file2"`` 3455 This syntax is only available with multiboot. 3456 3457 Use file1 and file2 as modules and pass arg=foo as parameter to the 3458 first module. 3459ERST 3460 3461DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3462 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3463SRST 3464``-dtb file`` 3465 Use file as a device tree binary (dtb) image and pass it to the 3466 kernel on boot. 3467ERST 3468 3469DEFHEADING() 3470 3471DEFHEADING(Debug/Expert options:) 3472 3473DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3474 "-fw_cfg [name=]<name>,file=<file>\n" 3475 " add named fw_cfg entry with contents from file\n" 3476 "-fw_cfg [name=]<name>,string=<str>\n" 3477 " add named fw_cfg entry with contents from string\n", 3478 QEMU_ARCH_ALL) 3479SRST 3480``-fw_cfg [name=]name,file=file`` 3481 Add named fw\_cfg entry with contents from file file. 3482 3483``-fw_cfg [name=]name,string=str`` 3484 Add named fw\_cfg entry with contents from string str. 3485 3486 The terminating NUL character of the contents of str will not be 3487 included as part of the fw\_cfg item data. To insert contents with 3488 embedded NUL characters, you have to use the file parameter. 3489 3490 The fw\_cfg entries are passed by QEMU through to the guest. 3491 3492 Example: 3493 3494 :: 3495 3496 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3497 3498 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3499 from ./my\_blob.bin. 3500ERST 3501 3502DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3503 "-serial dev redirect the serial port to char device 'dev'\n", 3504 QEMU_ARCH_ALL) 3505SRST 3506``-serial dev`` 3507 Redirect the virtual serial port to host character device dev. The 3508 default device is ``vc`` in graphical mode and ``stdio`` in non 3509 graphical mode. 3510 3511 This option can be used several times to simulate up to 4 serial 3512 ports. 3513 3514 Use ``-serial none`` to disable all serial ports. 3515 3516 Available character devices are: 3517 3518 ``vc[:WxH]`` 3519 Virtual console. Optionally, a width and height can be given in 3520 pixel with 3521 3522 :: 3523 3524 vc:800x600 3525 3526 It is also possible to specify width or height in characters: 3527 3528 :: 3529 3530 vc:80Cx24C 3531 3532 ``pty`` 3533 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3534 3535 ``none`` 3536 No device is allocated. 3537 3538 ``null`` 3539 void device 3540 3541 ``chardev:id`` 3542 Use a named character device defined with the ``-chardev`` 3543 option. 3544 3545 ``/dev/XXX`` 3546 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3547 port parameters are set according to the emulated ones. 3548 3549 ``/dev/parportN`` 3550 [Linux only, parallel port only] Use host parallel port N. 3551 Currently SPP and EPP parallel port features can be used. 3552 3553 ``file:filename`` 3554 Write output to filename. No character can be read. 3555 3556 ``stdio`` 3557 [Unix only] standard input/output 3558 3559 ``pipe:filename`` 3560 name pipe filename 3561 3562 ``COMn`` 3563 [Windows only] Use host serial port n 3564 3565 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3566 This implements UDP Net Console. When remote\_host or src\_ip 3567 are not specified they default to ``0.0.0.0``. When not using a 3568 specified src\_port a random port is automatically chosen. 3569 3570 If you just want a simple readonly console you can use 3571 ``netcat`` or ``nc``, by starting QEMU with: 3572 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3573 QEMU writes something to that port it will appear in the 3574 netconsole session. 3575 3576 If you plan to send characters back via netconsole or you want 3577 to stop and start QEMU a lot of times, you should have QEMU use 3578 the same source port each time by using something like ``-serial 3579 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3580 version of netcat which can listen to a TCP port and send and 3581 receive characters via udp. If you have a patched version of 3582 netcat which activates telnet remote echo and single char 3583 transfer, then you can use the following options to set up a 3584 netcat redirector to allow telnet on port 5555 to access the 3585 QEMU port. 3586 3587 ``QEMU Options:`` 3588 -serial udp::4555@:4556 3589 3590 ``netcat options:`` 3591 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3592 3593 ``telnet options:`` 3594 localhost 5555 3595 3596 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3597 The TCP Net Console has two modes of operation. It can send the 3598 serial I/O to a location or wait for a connection from a 3599 location. By default the TCP Net Console is sent to host at the 3600 port. If you use the ``server=on`` option QEMU will wait for a client 3601 socket application to connect to the port before continuing, 3602 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3603 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3604 option only applies if ``server=no`` is set, if the connection goes 3605 down it will attempt to reconnect at the given interval. If host 3606 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3607 time is accepted. You can use ``telnet=on`` to connect to the 3608 corresponding character device. 3609 3610 ``Example to send tcp console to 192.168.0.2 port 4444`` 3611 -serial tcp:192.168.0.2:4444 3612 3613 ``Example to listen and wait on port 4444 for connection`` 3614 -serial tcp::4444,server=on 3615 3616 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3617 -serial tcp:192.168.0.100:4444,server=on,wait=off 3618 3619 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3620 The telnet protocol is used instead of raw tcp sockets. The 3621 options work the same as if you had specified ``-serial tcp``. 3622 The difference is that the port acts like a telnet server or 3623 client using telnet option negotiation. This will also allow you 3624 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3625 supports sending the break sequence. Typically in unix telnet 3626 you do it with Control-] and then type "send break" followed by 3627 pressing the enter key. 3628 3629 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3630 The WebSocket protocol is used instead of raw tcp socket. The 3631 port acts as a WebSocket server. Client mode is not supported. 3632 3633 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3634 A unix domain socket is used instead of a tcp socket. The option 3635 works the same as if you had specified ``-serial tcp`` except 3636 the unix domain socket path is used for connections. 3637 3638 ``mon:dev_string`` 3639 This is a special option to allow the monitor to be multiplexed 3640 onto another serial port. The monitor is accessed with key 3641 sequence of Control-a and then pressing c. dev\_string should be 3642 any one of the serial devices specified above. An example to 3643 multiplex the monitor onto a telnet server listening on port 3644 4444 would be: 3645 3646 ``-serial mon:telnet::4444,server=on,wait=off`` 3647 3648 When the monitor is multiplexed to stdio in this way, Ctrl+C 3649 will not terminate QEMU any more but will be passed to the guest 3650 instead. 3651 3652 ``braille`` 3653 Braille device. This will use BrlAPI to display the braille 3654 output on a real or fake device. 3655 3656 ``msmouse`` 3657 Three button serial mouse. Configure the guest to use Microsoft 3658 protocol. 3659ERST 3660 3661DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3662 "-parallel dev redirect the parallel port to char device 'dev'\n", 3663 QEMU_ARCH_ALL) 3664SRST 3665``-parallel dev`` 3666 Redirect the virtual parallel port to host device dev (same devices 3667 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3668 to use hardware devices connected on the corresponding host parallel 3669 port. 3670 3671 This option can be used several times to simulate up to 3 parallel 3672 ports. 3673 3674 Use ``-parallel none`` to disable all parallel ports. 3675ERST 3676 3677DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3678 "-monitor dev redirect the monitor to char device 'dev'\n", 3679 QEMU_ARCH_ALL) 3680SRST 3681``-monitor dev`` 3682 Redirect the monitor to host device dev (same devices as the serial 3683 port). The default device is ``vc`` in graphical mode and ``stdio`` 3684 in non graphical mode. Use ``-monitor none`` to disable the default 3685 monitor. 3686ERST 3687DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3688 "-qmp dev like -monitor but opens in 'control' mode\n", 3689 QEMU_ARCH_ALL) 3690SRST 3691``-qmp dev`` 3692 Like -monitor but opens in 'control' mode. 3693ERST 3694DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3695 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3696 QEMU_ARCH_ALL) 3697SRST 3698``-qmp-pretty dev`` 3699 Like -qmp but uses pretty JSON formatting. 3700ERST 3701 3702DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3703 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3704SRST 3705``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3706 Setup monitor on chardev name. ``pretty`` turns on JSON pretty 3707 printing easing human reading and debugging. 3708ERST 3709 3710DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3711 "-debugcon dev redirect the debug console to char device 'dev'\n", 3712 QEMU_ARCH_ALL) 3713SRST 3714``-debugcon dev`` 3715 Redirect the debug console to host device dev (same devices as the 3716 serial port). The debug console is an I/O port which is typically 3717 port 0xe9; writing to that I/O port sends output to this device. The 3718 default device is ``vc`` in graphical mode and ``stdio`` in non 3719 graphical mode. 3720ERST 3721 3722DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3723 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3724SRST 3725``-pidfile file`` 3726 Store the QEMU process PID in file. It is useful if you launch QEMU 3727 from a script. 3728ERST 3729 3730DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3731 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3732SRST 3733``-singlestep`` 3734 Run the emulation in single step mode. 3735ERST 3736 3737DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3738 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3739 QEMU_ARCH_ALL) 3740SRST 3741``--preconfig`` 3742 Pause QEMU for interactive configuration before the machine is 3743 created, which allows querying and configuring properties that will 3744 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3745 exit the preconfig state and move to the next state (i.e. run guest 3746 if -S isn't used or pause the second time if -S is used). This 3747 option is experimental. 3748ERST 3749 3750DEF("S", 0, QEMU_OPTION_S, \ 3751 "-S freeze CPU at startup (use 'c' to start execution)\n", 3752 QEMU_ARCH_ALL) 3753SRST 3754``-S`` 3755 Do not start CPU at startup (you must type 'c' in the monitor). 3756ERST 3757 3758DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3759 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3760 " run qemu with overcommit hints\n" 3761 " mem-lock=on|off controls memory lock support (default: off)\n" 3762 " cpu-pm=on|off controls cpu power management (default: off)\n", 3763 QEMU_ARCH_ALL) 3764SRST 3765``-overcommit mem-lock=on|off`` 3766 \ 3767``-overcommit cpu-pm=on|off`` 3768 Run qemu with hints about host resource overcommit. The default is 3769 to assume that host overcommits all resources. 3770 3771 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3772 (disabled by default). This works when host memory is not 3773 overcommitted and reduces the worst-case latency for guest. 3774 3775 Guest ability to manage power state of host cpus (increasing latency 3776 for other processes on the same host cpu, but decreasing latency for 3777 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3778 works best when host CPU is not overcommitted. When used, host 3779 estimates of CPU cycle and power utilization will be incorrect, not 3780 taking into account guest idle time. 3781ERST 3782 3783DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3784 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3785 " the guest without waiting for gdb to connect; use -S too\n" 3786 " if you want it to not start execution.)\n", 3787 QEMU_ARCH_ALL) 3788SRST 3789``-gdb dev`` 3790 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3791 in the System Emulation Users Guide). Note that this option does not pause QEMU 3792 execution -- if you want QEMU to not start the guest until you 3793 connect with gdb and issue a ``continue`` command, you will need to 3794 also pass the ``-S`` option to QEMU. 3795 3796 The most usual configuration is to listen on a local TCP socket:: 3797 3798 -gdb tcp::3117 3799 3800 but you can specify other backends; UDP, pseudo TTY, or even stdio 3801 are all reasonable use cases. For example, a stdio connection 3802 allows you to start QEMU from within gdb and establish the 3803 connection via a pipe: 3804 3805 .. parsed-literal:: 3806 3807 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3808ERST 3809 3810DEF("s", 0, QEMU_OPTION_s, \ 3811 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3812 QEMU_ARCH_ALL) 3813SRST 3814``-s`` 3815 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3816 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3817ERST 3818 3819DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3820 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3821 QEMU_ARCH_ALL) 3822SRST 3823``-d item1[,...]`` 3824 Enable logging of specified items. Use '-d help' for a list of log 3825 items. 3826ERST 3827 3828DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3829 "-D logfile output log to logfile (default stderr)\n", 3830 QEMU_ARCH_ALL) 3831SRST 3832``-D logfile`` 3833 Output log in logfile instead of to stderr 3834ERST 3835 3836DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3837 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3838 QEMU_ARCH_ALL) 3839SRST 3840``-dfilter range1[,...]`` 3841 Filter debug output to that relevant to a range of target addresses. 3842 The filter spec can be either start+size, start-size or start..end 3843 where start end and size are the addresses and sizes required. For 3844 example: 3845 3846 :: 3847 3848 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3849 3850 Will dump output for any code in the 0x1000 sized block starting at 3851 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3852 another 0x1000 sized block starting at 0xffffffc00005f000. 3853ERST 3854 3855DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3856 "-seed number seed the pseudo-random number generator\n", 3857 QEMU_ARCH_ALL) 3858SRST 3859``-seed number`` 3860 Force the guest to use a deterministic pseudo-random number 3861 generator, seeded with number. This does not affect crypto routines 3862 within the host. 3863ERST 3864 3865DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3866 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3867 QEMU_ARCH_ALL) 3868SRST 3869``-L path`` 3870 Set the directory for the BIOS, VGA BIOS and keymaps. 3871 3872 To list all the data directories, use ``-L help``. 3873ERST 3874 3875DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3876 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3877SRST 3878``-bios file`` 3879 Set the filename for the BIOS. 3880ERST 3881 3882DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3883 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3884SRST 3885``-enable-kvm`` 3886 Enable KVM full virtualization support. This option is only 3887 available if KVM support is enabled when compiling. 3888ERST 3889 3890DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3891 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3892DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3893 "-xen-attach attach to existing xen domain\n" 3894 " libxl will use this when starting QEMU\n", 3895 QEMU_ARCH_ALL) 3896DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3897 "-xen-domid-restrict restrict set of available xen operations\n" 3898 " to specified domain id. (Does not affect\n" 3899 " xenpv machine type).\n", 3900 QEMU_ARCH_ALL) 3901SRST 3902``-xen-domid id`` 3903 Specify xen guest domain id (XEN only). 3904 3905``-xen-attach`` 3906 Attach to existing xen domain. libxl will use this when starting 3907 QEMU (XEN only). Restrict set of available xen operations to 3908 specified domain id (XEN only). 3909ERST 3910 3911DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3912 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3913SRST 3914``-no-reboot`` 3915 Exit instead of rebooting. 3916ERST 3917 3918DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3919 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3920SRST 3921``-no-shutdown`` 3922 Don't exit QEMU on guest shutdown, but instead only stop the 3923 emulation. This allows for instance switching to monitor to commit 3924 changes to the disk image. 3925ERST 3926 3927DEF("action", HAS_ARG, QEMU_OPTION_action, 3928 "-action reboot=reset|shutdown\n" 3929 " action when guest reboots [default=reset]\n" 3930 "-action shutdown=poweroff|pause\n" 3931 " action when guest shuts down [default=poweroff]\n" 3932 "-action panic=pause|shutdown|none\n" 3933 " action when guest panics [default=shutdown]\n" 3934 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 3935 " action when watchdog fires [default=reset]\n", 3936 QEMU_ARCH_ALL) 3937SRST 3938``-action event=action`` 3939 The action parameter serves to modify QEMU's default behavior when 3940 certain guest events occur. It provides a generic method for specifying the 3941 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 3942 parameters. 3943 3944 Examples: 3945 3946 ``-action panic=none`` 3947 ``-action reboot=shutdown,shutdown=pause`` 3948 ``-watchdog i6300esb -action watchdog=pause`` 3949 3950ERST 3951 3952DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3953 "-loadvm [tag|id]\n" \ 3954 " start right away with a saved state (loadvm in monitor)\n", 3955 QEMU_ARCH_ALL) 3956SRST 3957``-loadvm file`` 3958 Start right away with a saved state (``loadvm`` in monitor) 3959ERST 3960 3961#ifndef _WIN32 3962DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3963 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3964#endif 3965SRST 3966``-daemonize`` 3967 Daemonize the QEMU process after initialization. QEMU will not 3968 detach from standard IO until it is ready to receive connections on 3969 any of its devices. This option is a useful way for external 3970 programs to launch QEMU without having to cope with initialization 3971 race conditions. 3972ERST 3973 3974DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3975 "-option-rom rom load a file, rom, into the option ROM space\n", 3976 QEMU_ARCH_ALL) 3977SRST 3978``-option-rom file`` 3979 Load the contents of file as an option ROM. This option is useful to 3980 load things like EtherBoot. 3981ERST 3982 3983DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 3984 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 3985 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 3986 QEMU_ARCH_ALL) 3987 3988SRST 3989``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 3990 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 3991 the current UTC or local time, respectively. ``localtime`` is 3992 required for correct date in MS-DOS or Windows. To start at a 3993 specific point in time, provide datetime in the format 3994 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 3995 3996 By default the RTC is driven by the host system time. This allows 3997 using of the RTC as accurate reference clock inside the guest, 3998 specifically if the host time is smoothly following an accurate 3999 external reference clock, e.g. via NTP. If you want to isolate the 4000 guest time from the host, you can set ``clock`` to ``rt`` instead, 4001 which provides a host monotonic clock if host support it. To even 4002 prevent the RTC from progressing during suspension, you can set 4003 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4004 recommended especially in icount mode in order to preserve 4005 determinism; however, note that in icount mode the speed of the 4006 virtual clock is variable and can in general differ from the host 4007 clock. 4008 4009 Enable ``driftfix`` (i386 targets only) if you experience time drift 4010 problems, specifically with Windows' ACPI HAL. This option will try 4011 to figure out how many timer interrupts were not processed by the 4012 Windows guest and will re-inject them. 4013ERST 4014 4015DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4016 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4017 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4018 " instruction, enable aligning the host and virtual clocks\n" \ 4019 " or disable real time cpu sleeping, and optionally enable\n" \ 4020 " record-and-replay mode\n", QEMU_ARCH_ALL) 4021SRST 4022``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4023 Enable virtual instruction counter. The virtual cpu will execute one 4024 instruction every 2^N ns of virtual time. If ``auto`` is specified 4025 then the virtual cpu speed will be automatically adjusted to keep 4026 virtual time within a few seconds of real time. 4027 4028 Note that while this option can give deterministic behavior, it does 4029 not provide cycle accurate emulation. Modern CPUs contain 4030 superscalar out of order cores with complex cache hierarchies. The 4031 number of instructions executed often has little or no correlation 4032 with actual performance. 4033 4034 When the virtual cpu is sleeping, the virtual time will advance at 4035 default speed unless ``sleep=on`` is specified. With 4036 ``sleep=on``, the virtual time will jump to the next timer 4037 deadline instantly whenever the virtual cpu goes to sleep mode and 4038 will not advance if no timer is enabled. This behavior gives 4039 deterministic execution times from the guest point of view. 4040 The default if icount is enabled is ``sleep=off``. 4041 ``sleep=on`` cannot be used together with either ``shift=auto`` 4042 or ``align=on``. 4043 4044 ``align=on`` will activate the delay algorithm which will try to 4045 synchronise the host clock and the virtual clock. The goal is to 4046 have a guest running at the real frequency imposed by the shift 4047 option. Whenever the guest clock is behind the host clock and if 4048 ``align=on`` is specified then we print a message to the user to 4049 inform about the delay. Currently this option does not work when 4050 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4051 shift values for which the guest clock runs ahead of the host clock. 4052 Typically this happens when the shift value is high (how high 4053 depends on the host machine). The default if icount is enabled 4054 is ``align=off``. 4055 4056 When the ``rr`` option is specified deterministic record/replay is 4057 enabled. The ``rrfile=`` option must also be provided to 4058 specify the path to the replay log. In record mode data is written 4059 to this file, and in replay mode it is read back. 4060 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4061 name. In record mode, a new VM snapshot with the given name is created 4062 at the start of execution recording. In replay mode this option 4063 specifies the snapshot name used to load the initial VM state. 4064ERST 4065 4066DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4067 "-watchdog model\n" \ 4068 " enable virtual hardware watchdog [default=none]\n", 4069 QEMU_ARCH_ALL) 4070SRST 4071``-watchdog model`` 4072 Create a virtual hardware watchdog device. Once enabled (by a guest 4073 action), the watchdog must be periodically polled by an agent inside 4074 the guest or else the guest will be restarted. Choose a model for 4075 which your guest has drivers. 4076 4077 The model is the model of hardware watchdog to emulate. Use 4078 ``-watchdog help`` to list available hardware models. Only one 4079 watchdog can be enabled for a guest. 4080 4081 The following models may be available: 4082 4083 ``ib700`` 4084 iBASE 700 is a very simple ISA watchdog with a single timer. 4085 4086 ``i6300esb`` 4087 Intel 6300ESB I/O controller hub is a much more featureful 4088 PCI-based dual-timer watchdog. 4089 4090 ``diag288`` 4091 A virtual watchdog for s390x backed by the diagnose 288 4092 hypercall (currently KVM only). 4093ERST 4094 4095DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4096 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4097 " action when watchdog fires [default=reset]\n", 4098 QEMU_ARCH_ALL) 4099SRST 4100``-watchdog-action action`` 4101 The action controls what QEMU will do when the watchdog timer 4102 expires. The default is ``reset`` (forcefully reset the guest). 4103 Other possible actions are: ``shutdown`` (attempt to gracefully 4104 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4105 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4106 guest), ``debug`` (print a debug message and continue), or ``none`` 4107 (do nothing). 4108 4109 Note that the ``shutdown`` action requires that the guest responds 4110 to ACPI signals, which it may not be able to do in the sort of 4111 situations where the watchdog would have expired, and thus 4112 ``-watchdog-action shutdown`` is not recommended for production use. 4113 4114 Examples: 4115 4116 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4117 4118ERST 4119 4120DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4121 "-echr chr set terminal escape character instead of ctrl-a\n", 4122 QEMU_ARCH_ALL) 4123SRST 4124``-echr numeric_ascii_value`` 4125 Change the escape character used for switching to the monitor when 4126 using monitor and serial sharing. The default is ``0x01`` when using 4127 the ``-nographic`` option. ``0x01`` is equal to pressing 4128 ``Control-a``. You can select a different character from the ascii 4129 control keys where 1 through 26 map to Control-a through Control-z. 4130 For instance you could use the either of the following to change the 4131 escape character to Control-t. 4132 4133 ``-echr 0x14``; \ ``-echr 20`` 4134 4135ERST 4136 4137DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4138 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4139 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4140 "-incoming unix:socketpath\n" \ 4141 " prepare for incoming migration, listen on\n" \ 4142 " specified protocol and socket address\n" \ 4143 "-incoming fd:fd\n" \ 4144 "-incoming exec:cmdline\n" \ 4145 " accept incoming migration on given file descriptor\n" \ 4146 " or from given external command\n" \ 4147 "-incoming defer\n" \ 4148 " wait for the URI to be specified via migrate_incoming\n", 4149 QEMU_ARCH_ALL) 4150SRST 4151``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4152 \ 4153``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4154 Prepare for incoming migration, listen on a given tcp port. 4155 4156``-incoming unix:socketpath`` 4157 Prepare for incoming migration, listen on a given unix socket. 4158 4159``-incoming fd:fd`` 4160 Accept incoming migration from a given filedescriptor. 4161 4162``-incoming exec:cmdline`` 4163 Accept incoming migration as an output from specified external 4164 command. 4165 4166``-incoming defer`` 4167 Wait for the URI to be specified via migrate\_incoming. The monitor 4168 can be used to change settings (such as migration parameters) prior 4169 to issuing the migrate\_incoming to allow the migration to begin. 4170ERST 4171 4172DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4173 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4174SRST 4175``-only-migratable`` 4176 Only allow migratable devices. Devices will not be allowed to enter 4177 an unmigratable state. 4178ERST 4179 4180DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4181 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4182SRST 4183``-nodefaults`` 4184 Don't create default devices. Normally, QEMU sets the default 4185 devices like serial port, parallel port, virtual console, monitor 4186 device, VGA adapter, floppy and CD-ROM drive and others. The 4187 ``-nodefaults`` option will disable all those default devices. 4188ERST 4189 4190#ifndef _WIN32 4191DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4192 "-chroot dir chroot to dir just before starting the VM\n", 4193 QEMU_ARCH_ALL) 4194#endif 4195SRST 4196``-chroot dir`` 4197 Immediately before starting guest execution, chroot to the specified 4198 directory. Especially useful in combination with -runas. 4199ERST 4200 4201#ifndef _WIN32 4202DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4203 "-runas user change to user id user just before starting the VM\n" \ 4204 " user can be numeric uid:gid instead\n", 4205 QEMU_ARCH_ALL) 4206#endif 4207SRST 4208``-runas user`` 4209 Immediately before starting guest execution, drop root privileges, 4210 switching to the specified user. 4211ERST 4212 4213DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4214 "-prom-env variable=value\n" 4215 " set OpenBIOS nvram variables\n", 4216 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4217SRST 4218``-prom-env variable=value`` 4219 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4220 4221 :: 4222 4223 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4224 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4225 4226 :: 4227 4228 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4229 -prom-env 'boot-device=hd:2,\yaboot' \ 4230 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4231ERST 4232DEF("semihosting", 0, QEMU_OPTION_semihosting, 4233 "-semihosting semihosting mode\n", 4234 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4235 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4236SRST 4237``-semihosting`` 4238 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4239 4240 Note that this allows guest direct access to the host filesystem, so 4241 should only be used with a trusted guest OS. 4242 4243 See the -semihosting-config option documentation for further 4244 information about the facilities this enables. 4245ERST 4246DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4247 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4248 " semihosting configuration\n", 4249QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4250QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4251SRST 4252``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4253 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4254 only). 4255 4256 Note that this allows guest direct access to the host filesystem, so 4257 should only be used with a trusted guest OS. 4258 4259 On Arm this implements the standard semihosting API, version 2.0. 4260 4261 On M68K this implements the "ColdFire GDB" interface used by 4262 libgloss. 4263 4264 Xtensa semihosting provides basic file IO calls, such as 4265 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4266 linux platform "sim" use this interface. 4267 4268 On RISC-V this implements the standard semihosting API, version 0.2. 4269 4270 ``target=native|gdb|auto`` 4271 Defines where the semihosting calls will be addressed, to QEMU 4272 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4273 means ``gdb`` during debug sessions and ``native`` otherwise. 4274 4275 ``chardev=str1`` 4276 Send the output to a chardev backend output for native or auto 4277 output when not in gdb 4278 4279 ``arg=str1,arg=str2,...`` 4280 Allows the user to pass input arguments, and can be used 4281 multiple times to build up a list. The old-style 4282 ``-kernel``/``-append`` method of passing a command line is 4283 still supported for backward compatibility. If both the 4284 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4285 specified, the former is passed to semihosting as it always 4286 takes precedence. 4287ERST 4288DEF("old-param", 0, QEMU_OPTION_old_param, 4289 "-old-param old param mode\n", QEMU_ARCH_ARM) 4290SRST 4291``-old-param`` 4292 Old param mode (ARM only). 4293ERST 4294 4295DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4296 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4297 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4298 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4299 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4300 " by the kernel, but typically no longer used by modern\n" \ 4301 " C library implementations.\n" \ 4302 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \ 4303 " its privileges by blacklisting all set*uid|gid system calls.\n" \ 4304 " The value 'children' will deny set*uid|gid system calls for\n" \ 4305 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4306 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4307 " blacklisting *fork and execve\n" \ 4308 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4309 QEMU_ARCH_ALL) 4310SRST 4311``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4312 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4313 filtering and 'off' will disable it. The default is 'off'. 4314 4315 ``obsolete=string`` 4316 Enable Obsolete system calls 4317 4318 ``elevateprivileges=string`` 4319 Disable set\*uid\|gid system calls 4320 4321 ``spawn=string`` 4322 Disable \*fork and execve 4323 4324 ``resourcecontrol=string`` 4325 Disable process affinity and schedular priority 4326ERST 4327 4328DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4329 "-readconfig <file>\n", QEMU_ARCH_ALL) 4330SRST 4331``-readconfig file`` 4332 Read device configuration from file. This approach is useful when 4333 you want to spawn QEMU process with many command line options but 4334 you don't want to exceed the command line character limit. 4335ERST 4336DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4337 "-writeconfig <file>\n" 4338 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4339SRST 4340ERST 4341 4342DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4343 "-no-user-config\n" 4344 " do not load default user-provided config files at startup\n", 4345 QEMU_ARCH_ALL) 4346SRST 4347``-no-user-config`` 4348 The ``-no-user-config`` option makes QEMU not load any of the 4349 user-provided config files on sysconfdir. 4350ERST 4351 4352DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4353 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4354 " specify tracing options\n", 4355 QEMU_ARCH_ALL) 4356SRST 4357``-trace [[enable=]pattern][,events=file][,file=file]`` 4358 .. include:: ../qemu-option-trace.rst.inc 4359 4360ERST 4361DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4362 "-plugin [file=]<file>[,arg=<string>]\n" 4363 " load a plugin\n", 4364 QEMU_ARCH_ALL) 4365SRST 4366``-plugin file=file[,arg=string]`` 4367 Load a plugin. 4368 4369 ``file=file`` 4370 Load the given plugin from a shared library file. 4371 4372 ``arg=string`` 4373 Argument string passed to the plugin. (Can be given multiple 4374 times.) 4375ERST 4376 4377HXCOMM Internal use 4378DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4379DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4380 4381#ifdef __linux__ 4382DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4383 "-enable-fips enable FIPS 140-2 compliance\n", 4384 QEMU_ARCH_ALL) 4385#endif 4386SRST 4387``-enable-fips`` 4388 Enable FIPS 140-2 compliance mode. 4389ERST 4390 4391DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4392 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4393 " control error message format\n" 4394 " timestamp=on enables timestamps (default: off)\n" 4395 " guest-name=on enables guest name prefix but only if\n" 4396 " -name guest option is set (default: off)\n", 4397 QEMU_ARCH_ALL) 4398SRST 4399``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4400 Control error message format. 4401 4402 ``timestamp=on|off`` 4403 Prefix messages with a timestamp. Default is off. 4404 4405 ``guest-name=on|off`` 4406 Prefix messages with guest name but only if -name guest option is set 4407 otherwise the option is ignored. Default is off. 4408ERST 4409 4410DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4411 "-dump-vmstate <file>\n" 4412 " Output vmstate information in JSON format to file.\n" 4413 " Use the scripts/vmstate-static-checker.py file to\n" 4414 " check for possible regressions in migration code\n" 4415 " by comparing two such vmstate dumps.\n", 4416 QEMU_ARCH_ALL) 4417SRST 4418``-dump-vmstate file`` 4419 Dump json-encoded vmstate information for current machine type to 4420 file in file 4421ERST 4422 4423DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4424 "-enable-sync-profile\n" 4425 " enable synchronization profiling\n", 4426 QEMU_ARCH_ALL) 4427SRST 4428``-enable-sync-profile`` 4429 Enable synchronization profiling. 4430ERST 4431 4432DEFHEADING() 4433 4434DEFHEADING(Generic object creation:) 4435 4436DEF("object", HAS_ARG, QEMU_OPTION_object, 4437 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4438 " create a new object of type TYPENAME setting properties\n" 4439 " in the order they are specified. Note that the 'id'\n" 4440 " property must be set. These objects are placed in the\n" 4441 " '/objects' path.\n", 4442 QEMU_ARCH_ALL) 4443SRST 4444``-object typename[,prop1=value1,...]`` 4445 Create a new object of type typename setting properties in the order 4446 they are specified. Note that the 'id' property must be set. These 4447 objects are placed in the '/objects' path. 4448 4449 ``-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`` 4450 Creates a memory file backend object, which can be used to back 4451 the guest RAM with huge pages. 4452 4453 The ``id`` parameter is a unique ID that will be used to 4454 reference this memory region when configuring the ``-numa`` 4455 argument. 4456 4457 The ``size`` option provides the size of the memory region, and 4458 accepts common suffixes, eg ``500M``. 4459 4460 The ``mem-path`` provides the path to either a shared memory or 4461 huge page filesystem mount. 4462 4463 The ``share`` boolean option determines whether the memory 4464 region is marked as private to QEMU, or shared. The latter 4465 allows a co-operating external process to access the QEMU memory 4466 region. 4467 4468 The ``share`` is also required for pvrdma devices due to 4469 limitations in the RDMA API provided by Linux. 4470 4471 Setting share=on might affect the ability to configure NUMA 4472 bindings for the memory backend under some circumstances, see 4473 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4474 source tree for additional details. 4475 4476 Setting the ``discard-data`` boolean option to on indicates that 4477 file contents can be destroyed when QEMU exits, to avoid 4478 unnecessarily flushing data to the backing file. Note that 4479 ``discard-data`` is only an optimization, and QEMU might not 4480 discard file contents if it aborts unexpectedly or is terminated 4481 using SIGKILL. 4482 4483 The ``merge`` boolean option enables memory merge, also known as 4484 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4485 the pages for memory deduplication. 4486 4487 Setting the ``dump`` boolean option to off excludes the memory 4488 from core dumps. This feature is also known as MADV\_DONTDUMP. 4489 4490 The ``prealloc`` boolean option enables memory preallocation. 4491 4492 The ``host-nodes`` option binds the memory range to a list of 4493 NUMA host nodes. 4494 4495 The ``policy`` option sets the NUMA policy to one of the 4496 following values: 4497 4498 ``default`` 4499 default host policy 4500 4501 ``preferred`` 4502 prefer the given host node list for allocation 4503 4504 ``bind`` 4505 restrict memory allocation to the given host node list 4506 4507 ``interleave`` 4508 interleave memory allocations across the given host node 4509 list 4510 4511 The ``align`` option specifies the base address alignment when 4512 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4513 ``2M``. Some backend store specified by ``mem-path`` requires an 4514 alignment different than the default one used by QEMU, eg the 4515 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4516 such cases, users can specify the required alignment via this 4517 option. 4518 4519 The ``pmem`` option specifies whether the backing file specified 4520 by ``mem-path`` is in host persistent memory that can be 4521 accessed using the SNIA NVM programming model (e.g. Intel 4522 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4523 operations to guarantee the persistence of its own writes to 4524 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4525 migration). Also, we will map the backend-file with MAP\_SYNC 4526 flag, which ensures the file metadata is in sync for 4527 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4528 requires support from both the host kernel (since Linux kernel 4529 4.15) and the filesystem of ``mem-path`` mounted with DAX 4530 option. 4531 4532 The ``readonly`` option specifies whether the backing file is opened 4533 read-only or read-write (default). 4534 4535 ``-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`` 4536 Creates a memory backend object, which can be used to back the 4537 guest RAM. Memory backend objects offer more control than the 4538 ``-m`` option that is traditionally used to define guest RAM. 4539 Please refer to ``memory-backend-file`` for a description of the 4540 options. 4541 4542 ``-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`` 4543 Creates an anonymous memory file backend object, which allows 4544 QEMU to share the memory with an external process (e.g. when 4545 using vhost-user). The memory is allocated with memfd and 4546 optional sealing. (Linux only) 4547 4548 The ``seal`` option creates a sealed-file, that will block 4549 further resizing the memory ('on' by default). 4550 4551 The ``hugetlb`` option specify the file to be created resides in 4552 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4553 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4554 the hugetlb page size on systems that support multiple hugetlb 4555 page sizes (it must be a power of 2 value supported by the 4556 system). 4557 4558 In some versions of Linux, the ``hugetlb`` option is 4559 incompatible with the ``seal`` option (requires at least Linux 4560 4.16). 4561 4562 Please refer to ``memory-backend-file`` for a description of the 4563 other options. 4564 4565 The ``share`` boolean option is on by default with memfd. 4566 4567 ``-object rng-builtin,id=id`` 4568 Creates a random number generator backend which obtains entropy 4569 from QEMU builtin functions. The ``id`` parameter is a unique ID 4570 that will be used to reference this entropy backend from the 4571 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4572 uses this RNG backend. 4573 4574 ``-object rng-random,id=id,filename=/dev/random`` 4575 Creates a random number generator backend which obtains entropy 4576 from a device on the host. The ``id`` parameter is a unique ID 4577 that will be used to reference this entropy backend from the 4578 ``virtio-rng`` device. The ``filename`` parameter specifies 4579 which file to obtain entropy from and if omitted defaults to 4580 ``/dev/urandom``. 4581 4582 ``-object rng-egd,id=id,chardev=chardevid`` 4583 Creates a random number generator backend which obtains entropy 4584 from an external daemon running on the host. The ``id`` 4585 parameter is a unique ID that will be used to reference this 4586 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4587 parameter is the unique ID of a character device backend that 4588 provides the connection to the RNG daemon. 4589 4590 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4591 Creates a TLS anonymous credentials object, which can be used to 4592 provide TLS support on network backends. The ``id`` parameter is 4593 a unique ID which network backends will use to access the 4594 credentials. The ``endpoint`` is either ``server`` or ``client`` 4595 depending on whether the QEMU network backend that uses the 4596 credentials will be acting as a client or as a server. If 4597 ``verify-peer`` is enabled (the default) then once the handshake 4598 is completed, the peer credentials will be verified, though this 4599 is a no-op for anonymous credentials. 4600 4601 The dir parameter tells QEMU where to find the credential files. 4602 For server endpoints, this directory may contain a file 4603 dh-params.pem providing diffie-hellman parameters to use for the 4604 TLS server. If the file is missing, QEMU will generate a set of 4605 DH parameters at startup. This is a computationally expensive 4606 operation that consumes random pool entropy, so it is 4607 recommended that a persistent set of parameters be generated 4608 upfront and saved. 4609 4610 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4611 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4612 can be used to provide TLS support on network backends. The 4613 ``id`` parameter is a unique ID which network backends will use 4614 to access the credentials. The ``endpoint`` is either ``server`` 4615 or ``client`` depending on whether the QEMU network backend that 4616 uses the credentials will be acting as a client or as a server. 4617 For clients only, ``username`` is the username which will be 4618 sent to the server. If omitted it defaults to "qemu". 4619 4620 The dir parameter tells QEMU where to find the keys file. It is 4621 called "dir/keys.psk" and contains "username:key" pairs. This 4622 file can most easily be created using the GnuTLS ``psktool`` 4623 program. 4624 4625 For server endpoints, dir may also contain a file dh-params.pem 4626 providing diffie-hellman parameters to use for the TLS server. 4627 If the file is missing, QEMU will generate a set of DH 4628 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 up 4631 front and saved. 4632 4633 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4634 Creates a TLS anonymous credentials object, which can be used to 4635 provide TLS support on network backends. The ``id`` parameter is 4636 a unique ID which network backends will use to access the 4637 credentials. The ``endpoint`` is either ``server`` or ``client`` 4638 depending on whether the QEMU network backend that uses the 4639 credentials will be acting as a client or as a server. If 4640 ``verify-peer`` is enabled (the default) then once the handshake 4641 is completed, the peer credentials will be verified. With x509 4642 certificates, this implies that the clients must be provided 4643 with valid client certificates too. 4644 4645 The dir parameter tells QEMU where to find the credential files. 4646 For server endpoints, this directory may contain a file 4647 dh-params.pem providing diffie-hellman parameters to use for the 4648 TLS server. If the file is missing, QEMU will generate a set of 4649 DH parameters at startup. This is a computationally expensive 4650 operation that consumes random pool entropy, so it is 4651 recommended that a persistent set of parameters be generated 4652 upfront and saved. 4653 4654 For x509 certificate credentials the directory will contain 4655 further files providing the x509 certificates. The certificates 4656 must be stored in PEM format, in filenames ca-cert.pem, 4657 ca-crl.pem (optional), server-cert.pem (only servers), 4658 server-key.pem (only servers), client-cert.pem (only clients), 4659 and client-key.pem (only clients). 4660 4661 For the server-key.pem and client-key.pem files which contain 4662 sensitive private keys, it is possible to use an encrypted 4663 version by providing the passwordid parameter. This provides the 4664 ID of a previously created ``secret`` object containing the 4665 password for decryption. 4666 4667 The priority parameter allows to override the global default 4668 priority used by gnutls. This can be useful if the system 4669 administrator needs to use a weaker set of crypto priorities for 4670 QEMU without potentially forcing the weakness onto all 4671 applications. Or conversely if one wants wants a stronger 4672 default for QEMU than for all other applications, they can do 4673 this through this parameter. Its format is a gnutls priority 4674 string as described at 4675 https://gnutls.org/manual/html_node/Priority-Strings.html. 4676 4677 ``-object tls-cipher-suites,id=id,priority=priority`` 4678 Creates a TLS cipher suites object, which can be used to control 4679 the TLS cipher/protocol algorithms that applications are permitted 4680 to use. 4681 4682 The ``id`` parameter is a unique ID which frontends will use to 4683 access the ordered list of permitted TLS cipher suites from the 4684 host. 4685 4686 The ``priority`` parameter allows to override the global default 4687 priority used by gnutls. This can be useful if the system 4688 administrator needs to use a weaker set of crypto priorities for 4689 QEMU without potentially forcing the weakness onto all 4690 applications. Or conversely if one wants wants a stronger 4691 default for QEMU than for all other applications, they can do 4692 this through this parameter. Its format is a gnutls priority 4693 string as described at 4694 https://gnutls.org/manual/html_node/Priority-Strings.html. 4695 4696 An example of use of this object is to control UEFI HTTPS Boot. 4697 The tls-cipher-suites object exposes the ordered list of permitted 4698 TLS cipher suites from the host side to the guest firmware, via 4699 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4700 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4701 guest-side TLS. 4702 4703 In the following example, the priority at which the host-side policy 4704 is retrieved is given by the ``priority`` property. 4705 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4706 refer to /etc/crypto-policies/back-ends/gnutls.config. 4707 4708 .. parsed-literal:: 4709 4710 # |qemu_system| \\ 4711 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4712 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4713 4714 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4715 Interval t can't be 0, this filter batches the packet delivery: 4716 all packets arriving in a given interval on netdev netdevid are 4717 delayed until the end of the interval. Interval is in 4718 microseconds. ``status`` is optional that indicate whether the 4719 netfilter is on (enabled) or off (disabled), the default status 4720 for netfilter will be 'on'. 4721 4722 queue all\|rx\|tx is an option that can be applied to any 4723 netfilter. 4724 4725 ``all``: the filter is attached both to the receive and the 4726 transmit queue of the netdev (default). 4727 4728 ``rx``: the filter is attached to the receive queue of the 4729 netdev, where it will receive packets sent to the netdev. 4730 4731 ``tx``: the filter is attached to the transmit queue of the 4732 netdev, where it will receive packets sent by the netdev. 4733 4734 position head\|tail\|id=<id> is an option to specify where the 4735 filter should be inserted in the filter list. It can be applied 4736 to any netfilter. 4737 4738 ``head``: the filter is inserted at the head of the filter list, 4739 before any existing filters. 4740 4741 ``tail``: the filter is inserted at the tail of the filter list, 4742 behind any existing filters (default). 4743 4744 ``id=<id>``: the filter is inserted before or behind the filter 4745 specified by <id>, see the insert option below. 4746 4747 insert behind\|before is an option to specify where to insert 4748 the new filter relative to the one specified with 4749 position=id=<id>. It can be applied to any netfilter. 4750 4751 ``before``: insert before the specified filter. 4752 4753 ``behind``: insert behind the specified filter (default). 4754 4755 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4756 filter-mirror on netdev netdevid,mirror net packet to 4757 chardevchardevid, if it has the vnet\_hdr\_support flag, 4758 filter-mirror will mirror packet with vnet\_hdr\_len. 4759 4760 ``-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]`` 4761 filter-redirector on netdev netdevid,redirect filter's net 4762 packet to chardev chardevid,and redirect indev's packet to 4763 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4764 will redirect packet with vnet\_hdr\_len. Create a 4765 filter-redirector we need to differ outdev id from indev id, id 4766 can not be the same. we can just use indev or outdev, but at 4767 least one of indev or outdev need to be specified. 4768 4769 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4770 Filter-rewriter is a part of COLO project.It will rewrite tcp 4771 packet to secondary from primary to keep secondary tcp 4772 connection,and rewrite tcp packet to primary from secondary make 4773 tcp packet can be handled by client.if it has the 4774 vnet\_hdr\_support flag, we can parse packet with vnet header. 4775 4776 usage: colo secondary: -object 4777 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4778 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4779 filter-rewriter,id=rew0,netdev=hn0,queue=all 4780 4781 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4782 Dump the network traffic on netdev dev to the file specified by 4783 filename. At most len bytes (64k by default) per packet are 4784 stored. The file format is libpcap, so it can be analyzed with 4785 tools such as tcpdump or Wireshark. 4786 4787 ``-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}]`` 4788 Colo-compare gets packet from primary\_in chardevid and 4789 secondary\_in, then compare whether the payload of primary packet 4790 and secondary packet are the same. If same, it will output 4791 primary packet to out\_dev, else it will notify COLO-framework to do 4792 checkpoint and send primary packet to out\_dev. In order to 4793 improve efficiency, we need to put the task of comparison in 4794 another iothread. If it has the vnet\_hdr\_support flag, 4795 colo compare will send/recv packet with vnet\_hdr\_len. 4796 The compare\_timeout=@var{ms} determines the maximum time of the 4797 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4798 is to set the period of scanning expired primary node network packets. 4799 The max\_queue\_size=@var{size} is to set the max compare queue 4800 size depend on user environment. 4801 If user want to use Xen COLO, need to add the notify\_dev to 4802 notify Xen colo-frame to do checkpoint. 4803 4804 COLO-compare must be used with the help of filter-mirror, 4805 filter-redirector and filter-rewriter. 4806 4807 :: 4808 4809 KVM COLO 4810 4811 primary: 4812 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4813 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4814 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4815 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4816 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4817 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4818 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4819 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4820 -object iothread,id=iothread1 4821 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4822 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4823 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4824 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4825 4826 secondary: 4827 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4828 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4829 -chardev socket,id=red0,host=3.3.3.3,port=9003 4830 -chardev socket,id=red1,host=3.3.3.3,port=9004 4831 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4832 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4833 4834 4835 Xen COLO 4836 4837 primary: 4838 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4839 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4840 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4841 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4842 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4843 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4844 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4845 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4846 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4847 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4848 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4849 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4850 -object iothread,id=iothread1 4851 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4852 4853 secondary: 4854 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4855 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4856 -chardev socket,id=red0,host=3.3.3.3,port=9003 4857 -chardev socket,id=red1,host=3.3.3.3,port=9004 4858 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4859 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4860 4861 If you want to know the detail of above command line, you can 4862 read the colo-compare git log. 4863 4864 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4865 Creates a cryptodev backend which executes crypto opreation from 4866 the QEMU cipher APIS. The id parameter is a unique ID that will 4867 be used to reference this cryptodev backend from the 4868 ``virtio-crypto`` device. The queues parameter is optional, 4869 which specify the queue number of cryptodev backend, the default 4870 of queues is 1. 4871 4872 .. parsed-literal:: 4873 4874 # |qemu_system| \\ 4875 [...] \\ 4876 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4877 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4878 [...] 4879 4880 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4881 Creates a vhost-user cryptodev backend, backed by a chardev 4882 chardevid. The id parameter is a unique ID that will be used to 4883 reference this cryptodev backend from the ``virtio-crypto`` 4884 device. The chardev should be a unix domain socket backed one. 4885 The vhost-user uses a specifically defined protocol to pass 4886 vhost ioctl replacement messages to an application on the other 4887 end of the socket. The queues parameter is optional, which 4888 specify the queue number of cryptodev backend for multiqueue 4889 vhost-user, the default of queues is 1. 4890 4891 .. parsed-literal:: 4892 4893 # |qemu_system| \\ 4894 [...] \\ 4895 -chardev socket,id=chardev0,path=/path/to/socket \\ 4896 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4897 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4898 [...] 4899 4900 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 4901 \ 4902 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 4903 Defines a secret to store a password, encryption key, or some 4904 other sensitive data. The sensitive data can either be passed 4905 directly via the data parameter, or indirectly via the file 4906 parameter. Using the data parameter is insecure unless the 4907 sensitive data is encrypted. 4908 4909 The sensitive data can be provided in raw format (the default), 4910 or base64. When encoded as JSON, the raw format only supports 4911 valid UTF-8 characters, so base64 is recommended for sending 4912 binary data. QEMU will convert from which ever format is 4913 provided to the format it needs internally. eg, an RBD password 4914 can be provided in raw format, even though it will be base64 4915 encoded when passed onto the RBD sever. 4916 4917 For added protection, it is possible to encrypt the data 4918 associated with a secret using the AES-256-CBC cipher. Use of 4919 encryption is indicated by providing the keyid and iv 4920 parameters. The keyid parameter provides the ID of a previously 4921 defined secret that contains the AES-256 decryption key. This 4922 key should be 32-bytes long and be base64 encoded. The iv 4923 parameter provides the random initialization vector used for 4924 encryption of this particular secret and should be a base64 4925 encrypted string of the 16-byte IV. 4926 4927 The simplest (insecure) usage is to provide the secret inline 4928 4929 .. parsed-literal:: 4930 4931 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 4932 4933 The simplest secure usage is to provide the secret via a file 4934 4935 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 4936 secret,id=sec0,file=mypasswd.txt,format=raw 4937 4938 For greater security, AES-256-CBC should be used. To illustrate 4939 usage, consider the openssl command line tool which can encrypt 4940 the data. Note that when encrypting, the plaintext must be 4941 padded to the cipher block size (32 bytes) using the standard 4942 PKCS#5/6 compatible padding algorithm. 4943 4944 First a master key needs to be created in base64 encoding: 4945 4946 :: 4947 4948 # openssl rand -base64 32 > key.b64 4949 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4950 4951 Each secret to be encrypted needs to have a random 4952 initialization vector generated. These do not need to be kept 4953 secret 4954 4955 :: 4956 4957 # openssl rand -base64 16 > iv.b64 4958 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4959 4960 The secret to be defined can now be encrypted, in this case 4961 we're telling openssl to base64 encode the result, but it could 4962 be left as raw bytes if desired. 4963 4964 :: 4965 4966 # SECRET=$(printf "letmein" | 4967 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4968 4969 When launching QEMU, create a master secret pointing to 4970 ``key.b64`` and specify that to be used to decrypt the user 4971 password. Pass the contents of ``iv.b64`` to the second secret 4972 4973 .. parsed-literal:: 4974 4975 # |qemu_system| \\ 4976 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 4977 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 4978 data=$SECRET,iv=$(<iv.b64) 4979 4980 ``-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]`` 4981 Create a Secure Encrypted Virtualization (SEV) guest object, 4982 which can be used to provide the guest memory encryption support 4983 on AMD processors. 4984 4985 When memory encryption is enabled, one of the physical address 4986 bit (aka the C-bit) is utilized to mark if a memory page is 4987 protected. The ``cbitpos`` is used to provide the C-bit 4988 position. The C-bit position is Host family dependent hence user 4989 must provide this value. On EPYC, the value should be 47. 4990 4991 When memory encryption is enabled, we loose certain bits in 4992 physical address space. The ``reduced-phys-bits`` is used to 4993 provide the number of bits we loose in physical address space. 4994 Similar to C-bit, the value is Host family dependent. On EPYC, 4995 the value should be 5. 4996 4997 The ``sev-device`` provides the device file to use for 4998 communicating with the SEV firmware running inside AMD Secure 4999 Processor. The default device is '/dev/sev'. If hardware 5000 supports memory encryption then /dev/sev devices are created by 5001 CCP driver. 5002 5003 The ``policy`` provides the guest policy to be enforced by the 5004 SEV firmware and restrict what configuration and operational 5005 commands can be performed on this guest by the hypervisor. The 5006 policy should be provided by the guest owner and is bound to the 5007 guest and cannot be changed throughout the lifetime of the 5008 guest. The default is 0. 5009 5010 If guest ``policy`` allows sharing the key with another SEV 5011 guest then ``handle`` can be use to provide handle of the guest 5012 from which to share the key. 5013 5014 The ``dh-cert-file`` and ``session-file`` provides the guest 5015 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5016 and session parameters are used for establishing a cryptographic 5017 session with the guest owner to negotiate keys used for 5018 attestation. The file must be encoded in base64. 5019 5020 e.g to launch a SEV guest 5021 5022 .. parsed-literal:: 5023 5024 # |qemu_system_x86| \\ 5025 ...... \\ 5026 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5027 -machine ...,memory-encryption=sev0 \\ 5028 ..... 5029 5030 ``-object authz-simple,id=id,identity=string`` 5031 Create an authorization object that will control access to 5032 network services. 5033 5034 The ``identity`` parameter is identifies the user and its format 5035 depends on the network service that authorization object is 5036 associated with. For authorizing based on TLS x509 certificates, 5037 the identity must be the x509 distinguished name. Note that care 5038 must be taken to escape any commas in the distinguished name. 5039 5040 An example authorization object to validate a x509 distinguished 5041 name would look like: 5042 5043 .. parsed-literal:: 5044 5045 # |qemu_system| \\ 5046 ... \\ 5047 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5048 ... 5049 5050 Note the use of quotes due to the x509 distinguished name 5051 containing whitespace, and escaping of ','. 5052 5053 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5054 Create an authorization object that will control access to 5055 network services. 5056 5057 The ``filename`` parameter is the fully qualified path to a file 5058 containing the access control list rules in JSON format. 5059 5060 An example set of rules that match against SASL usernames might 5061 look like: 5062 5063 :: 5064 5065 { 5066 "rules": [ 5067 { "match": "fred", "policy": "allow", "format": "exact" }, 5068 { "match": "bob", "policy": "allow", "format": "exact" }, 5069 { "match": "danb", "policy": "deny", "format": "glob" }, 5070 { "match": "dan*", "policy": "allow", "format": "exact" }, 5071 ], 5072 "policy": "deny" 5073 } 5074 5075 When checking access the object will iterate over all the rules 5076 and the first rule to match will have its ``policy`` value 5077 returned as the result. If no rules match, then the default 5078 ``policy`` value is returned. 5079 5080 The rules can either be an exact string match, or they can use 5081 the simple UNIX glob pattern matching to allow wildcards to be 5082 used. 5083 5084 If ``refresh`` is set to true the file will be monitored and 5085 automatically reloaded whenever its content changes. 5086 5087 As with the ``authz-simple`` object, the format of the identity 5088 strings being matched depends on the network service, but is 5089 usually a TLS x509 distinguished name, or a SASL username. 5090 5091 An example authorization object to validate a SASL username 5092 would look like: 5093 5094 .. parsed-literal:: 5095 5096 # |qemu_system| \\ 5097 ... \\ 5098 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5099 ... 5100 5101 ``-object authz-pam,id=id,service=string`` 5102 Create an authorization object that will control access to 5103 network services. 5104 5105 The ``service`` parameter provides the name of a PAM service to 5106 use for authorization. It requires that a file 5107 ``/etc/pam.d/service`` exist to provide the configuration for 5108 the ``account`` subsystem. 5109 5110 An example authorization object to validate a TLS x509 5111 distinguished name would look like: 5112 5113 .. parsed-literal:: 5114 5115 # |qemu_system| \\ 5116 ... \\ 5117 -object authz-pam,id=auth0,service=qemu-vnc \\ 5118 ... 5119 5120 There would then be a corresponding config file for PAM at 5121 ``/etc/pam.d/qemu-vnc`` that contains: 5122 5123 :: 5124 5125 account requisite pam_listfile.so item=user sense=allow \ 5126 file=/etc/qemu/vnc.allow 5127 5128 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5129 of x509 distingished names that are permitted access 5130 5131 :: 5132 5133 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5134 5135 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5136 Creates a dedicated event loop thread that devices can be 5137 assigned to. This is known as an IOThread. By default device 5138 emulation happens in vCPU threads or the main event loop thread. 5139 This can become a scalability bottleneck. IOThreads allow device 5140 emulation and I/O to run on other host CPUs. 5141 5142 The ``id`` parameter is a unique ID that will be used to 5143 reference this IOThread from ``-device ...,iothread=id``. 5144 Multiple devices can be assigned to an IOThread. Note that not 5145 all devices support an ``iothread`` parameter. 5146 5147 The ``query-iothreads`` QMP command lists IOThreads and reports 5148 their thread IDs so that the user can configure host CPU 5149 pinning/affinity. 5150 5151 IOThreads use an adaptive polling algorithm to reduce event loop 5152 latency. Instead of entering a blocking system call to monitor 5153 file descriptors and then pay the cost of being woken up when an 5154 event occurs, the polling algorithm spins waiting for events for 5155 a short time. The algorithm's default parameters are suitable 5156 for many cases but can be adjusted based on knowledge of the 5157 workload and/or host device latency. 5158 5159 The ``poll-max-ns`` parameter is the maximum number of 5160 nanoseconds to busy wait for events. Polling can be disabled by 5161 setting this value to 0. 5162 5163 The ``poll-grow`` parameter is the multiplier used to increase 5164 the polling time when the algorithm detects it is missing events 5165 due to not polling long enough. 5166 5167 The ``poll-shrink`` parameter is the divisor used to decrease 5168 the polling time when the algorithm detects it is spending too 5169 long polling without encountering events. 5170 5171 The polling parameters can be modified at run-time using the 5172 ``qom-set`` command (where ``iothread1`` is the IOThread's 5173 ``id``): 5174 5175 :: 5176 5177 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5178ERST 5179 5180 5181HXCOMM This is the last statement. Insert new options before this line! 5182
