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 therefor 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][,ipv4|ipv6|unix]\n" 1898 " [,tls-ciphers=<list>]\n" 1899 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1900 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1901 " [,sasl][,password=<secret>][,disable-ticketing]\n" 1902 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1903 " [,jpeg-wan-compression=[auto|never|always]]\n" 1904 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1905 " [,streaming-video=[off|all|filter]][,disable-copy-paste]\n" 1906 " [,disable-agent-file-xfer][,agent-mouse=[on|off]]\n" 1907 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1908 " [,gl=[on|off]][,rendernode=<file>]\n" 1909 " enable spice\n" 1910 " at least one of {port, tls-port} is mandatory\n", 1911 QEMU_ARCH_ALL) 1912SRST 1913``-spice option[,option[,...]]`` 1914 Enable the spice remote desktop protocol. Valid options are 1915 1916 ``port=<nr>`` 1917 Set the TCP port spice is listening on for plaintext channels. 1918 1919 ``addr=<addr>`` 1920 Set the IP address spice is listening on. Default is any 1921 address. 1922 1923 ``ipv4``; \ ``ipv6``; \ ``unix`` 1924 Force using the specified IP version. 1925 1926 ``password=<secret>`` 1927 Set the password you need to authenticate. 1928 1929 ``sasl`` 1930 Require that the client use SASL to authenticate with the spice. 1931 The exact choice of authentication method used is controlled 1932 from the system / user's SASL configuration file for the 'qemu' 1933 service. This is typically found in /etc/sasl2/qemu.conf. If 1934 running QEMU as an unprivileged user, an environment variable 1935 SASL\_CONF\_PATH can be used to make it search alternate 1936 locations for the service config. While some SASL auth methods 1937 can also provide data encryption (eg GSSAPI), it is recommended 1938 that SASL always be combined with the 'tls' and 'x509' settings 1939 to enable use of SSL and server certificates. This ensures a 1940 data encryption preventing compromise of authentication 1941 credentials. 1942 1943 ``disable-ticketing`` 1944 Allow client connects without authentication. 1945 1946 ``disable-copy-paste`` 1947 Disable copy paste between the client and the guest. 1948 1949 ``disable-agent-file-xfer`` 1950 Disable spice-vdagent based file-xfer between the client and the 1951 guest. 1952 1953 ``tls-port=<nr>`` 1954 Set the TCP port spice is listening on for encrypted channels. 1955 1956 ``x509-dir=<dir>`` 1957 Set the x509 file directory. Expects same filenames as -vnc 1958 $display,x509=$dir 1959 1960 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 1961 The x509 file names can also be configured individually. 1962 1963 ``tls-ciphers=<list>`` 1964 Specify which ciphers to use. 1965 1966 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 1967 Force specific channel to be used with or without TLS 1968 encryption. The options can be specified multiple times to 1969 configure multiple channels. The special name "default" can be 1970 used to set the default mode. For channels which are not 1971 explicitly forced into one mode the spice client is allowed to 1972 pick tls/plaintext as he pleases. 1973 1974 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 1975 Configure image compression (lossless). Default is auto\_glz. 1976 1977 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 1978 Configure wan image compression (lossy for slow links). Default 1979 is auto. 1980 1981 ``streaming-video=[off|all|filter]`` 1982 Configure video stream detection. Default is off. 1983 1984 ``agent-mouse=[on|off]`` 1985 Enable/disable passing mouse events via vdagent. Default is on. 1986 1987 ``playback-compression=[on|off]`` 1988 Enable/disable audio stream compression (using celt 0.5.1). 1989 Default is on. 1990 1991 ``seamless-migration=[on|off]`` 1992 Enable/disable spice seamless migration. Default is off. 1993 1994 ``gl=[on|off]`` 1995 Enable/disable OpenGL context. Default is off. 1996 1997 ``rendernode=<file>`` 1998 DRM render node for OpenGL rendering. If not specified, it will 1999 pick the first available. (Since 2.9) 2000ERST 2001 2002DEF("portrait", 0, QEMU_OPTION_portrait, 2003 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2004 QEMU_ARCH_ALL) 2005SRST 2006``-portrait`` 2007 Rotate graphical output 90 deg left (only PXA LCD). 2008ERST 2009 2010DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2011 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2012 QEMU_ARCH_ALL) 2013SRST 2014``-rotate deg`` 2015 Rotate graphical output some deg left (only PXA LCD). 2016ERST 2017 2018DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2019 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2020 " select video card type\n", QEMU_ARCH_ALL) 2021SRST 2022``-vga type`` 2023 Select type of VGA card to emulate. Valid values for type are 2024 2025 ``cirrus`` 2026 Cirrus Logic GD5446 Video card. All Windows versions starting 2027 from Windows 95 should recognize and use this graphic card. For 2028 optimal performances, use 16 bit color depth in the guest and 2029 the host OS. (This card was the default before QEMU 2.2) 2030 2031 ``std`` 2032 Standard VGA card with Bochs VBE extensions. If your guest OS 2033 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2034 you want to use high resolution modes (>= 1280x1024x16) then you 2035 should use this option. (This card is the default since QEMU 2036 2.2) 2037 2038 ``vmware`` 2039 VMWare SVGA-II compatible adapter. Use it if you have 2040 sufficiently recent XFree86/XOrg server or Windows guest with a 2041 driver for this card. 2042 2043 ``qxl`` 2044 QXL paravirtual graphic card. It is VGA compatible (including 2045 VESA 2.0 VBE support). Works best with qxl guest drivers 2046 installed though. Recommended choice when using the spice 2047 protocol. 2048 2049 ``tcx`` 2050 (sun4m only) Sun TCX framebuffer. This is the default 2051 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2052 colour depths at a fixed resolution of 1024x768. 2053 2054 ``cg3`` 2055 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2056 framebuffer for sun4m machines available in both 1024x768 2057 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2058 wishing to run older Solaris versions. 2059 2060 ``virtio`` 2061 Virtio VGA card. 2062 2063 ``none`` 2064 Disable VGA card. 2065ERST 2066 2067DEF("full-screen", 0, QEMU_OPTION_full_screen, 2068 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2069SRST 2070``-full-screen`` 2071 Start in full screen. 2072ERST 2073 2074DEF("g", HAS_ARG, QEMU_OPTION_g , 2075 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2076 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2077SRST 2078``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2079 Set the initial graphical resolution and depth (PPC, SPARC only). 2080 2081 For PPC the default is 800x600x32. 2082 2083 For SPARC with the TCX graphics device, the default is 1024x768x8 2084 with the option of 1024x768x24. For cgthree, the default is 2085 1024x768x8 with the option of 1152x900x8 for people who wish to use 2086 OBP. 2087ERST 2088 2089DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2090 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2091SRST 2092``-vnc display[,option[,option[,...]]]`` 2093 Normally, if QEMU is compiled with graphical window support, it 2094 displays output such as guest graphics, guest console, and the QEMU 2095 monitor in a window. With this option, you can have QEMU listen on 2096 VNC display display and redirect the VGA display over the VNC 2097 session. It is very useful to enable the usb tablet device when 2098 using this option (option ``-device usb-tablet``). When using the 2099 VNC display, you must use the ``-k`` parameter to set the keyboard 2100 layout if you are not using en-us. Valid syntax for the display is 2101 2102 ``to=L`` 2103 With this option, QEMU will try next available VNC displays, 2104 until the number L, if the origianlly defined "-vnc display" is 2105 not available, e.g. port 5900+display is already used by another 2106 application. By default, to=0. 2107 2108 ``host:d`` 2109 TCP connections will only be allowed from host on display d. By 2110 convention the TCP port is 5900+d. Optionally, host can be 2111 omitted in which case the server will accept connections from 2112 any host. 2113 2114 ``unix:path`` 2115 Connections will be allowed over UNIX domain sockets where path 2116 is the location of a unix socket to listen for connections on. 2117 2118 ``none`` 2119 VNC is initialized but not started. The monitor ``change`` 2120 command can be used to later start the VNC server. 2121 2122 Following the display value there may be one or more option flags 2123 separated by commas. Valid options are 2124 2125 ``reverse`` 2126 Connect to a listening VNC client via a "reverse" connection. 2127 The client is specified by the display. For reverse network 2128 connections (host:d,``reverse``), the d argument is a TCP port 2129 number, not a display number. 2130 2131 ``websocket`` 2132 Opens an additional TCP listening port dedicated to VNC 2133 Websocket connections. If a bare websocket option is given, the 2134 Websocket port is 5700+display. An alternative port can be 2135 specified with the syntax ``websocket``\ =port. 2136 2137 If host is specified connections will only be allowed from this 2138 host. It is possible to control the websocket listen address 2139 independently, using the syntax ``websocket``\ =host:port. 2140 2141 If no TLS credentials are provided, the websocket connection 2142 runs in unencrypted mode. If TLS credentials are provided, the 2143 websocket connection requires encrypted client connections. 2144 2145 ``password`` 2146 Require that password based authentication is used for client 2147 connections. 2148 2149 The password must be set separately using the ``set_password`` 2150 command in the :ref:`QEMU monitor`. The 2151 syntax to change your password is: 2152 ``set_password <protocol> <password>`` where <protocol> could be 2153 either "vnc" or "spice". 2154 2155 If you would like to change <protocol> password expiration, you 2156 should use ``expire_password <protocol> <expiration-time>`` 2157 where expiration time could be one of the following options: 2158 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2159 make password expire in 60 seconds, or 1335196800 to make 2160 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2161 this date and time). 2162 2163 You can also use keywords "now" or "never" for the expiration 2164 time to allow <protocol> password to expire immediately or never 2165 expire. 2166 2167 ``tls-creds=ID`` 2168 Provides the ID of a set of TLS credentials to use to secure the 2169 VNC server. They will apply to both the normal VNC server socket 2170 and the websocket socket (if enabled). Setting TLS credentials 2171 will cause the VNC server socket to enable the VeNCrypt auth 2172 mechanism. The credentials should have been previously created 2173 using the ``-object tls-creds`` argument. 2174 2175 ``tls-authz=ID`` 2176 Provides the ID of the QAuthZ authorization object against which 2177 the client's x509 distinguished name will validated. This object 2178 is only resolved at time of use, so can be deleted and recreated 2179 on the fly while the VNC server is active. If missing, it will 2180 default to denying access. 2181 2182 ``sasl`` 2183 Require that the client use SASL to authenticate with the VNC 2184 server. The exact choice of authentication method used is 2185 controlled from the system / user's SASL configuration file for 2186 the 'qemu' service. This is typically found in 2187 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2188 an environment variable SASL\_CONF\_PATH can be used to make it 2189 search alternate locations for the service config. While some 2190 SASL auth methods can also provide data encryption (eg GSSAPI), 2191 it is recommended that SASL always be combined with the 'tls' 2192 and 'x509' settings to enable use of SSL and server 2193 certificates. This ensures a data encryption preventing 2194 compromise of authentication credentials. See the 2195 :ref:`VNC security` section in the System Emulation Users Guide 2196 for details on using SASL authentication. 2197 2198 ``sasl-authz=ID`` 2199 Provides the ID of the QAuthZ authorization object against which 2200 the client's SASL username will validated. This object is only 2201 resolved at time of use, so can be deleted and recreated on the 2202 fly while the VNC server is active. If missing, it will default 2203 to denying access. 2204 2205 ``acl`` 2206 Legacy method for enabling authorization of clients against the 2207 x509 distinguished name and SASL username. It results in the 2208 creation of two ``authz-list`` objects with IDs of 2209 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2210 objects must be configured with the HMP ACL commands. 2211 2212 This option is deprecated and should no longer be used. The new 2213 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2214 2215 ``lossy`` 2216 Enable lossy compression methods (gradient, JPEG, ...). If this 2217 option is set, VNC client may receive lossy framebuffer updates 2218 depending on its encoding settings. Enabling this option can 2219 save a lot of bandwidth at the expense of quality. 2220 2221 ``non-adaptive`` 2222 Disable adaptive encodings. Adaptive encodings are enabled by 2223 default. An adaptive encoding will try to detect frequently 2224 updated screen regions, and send updates in these regions using 2225 a lossy encoding (like JPEG). This can be really helpful to save 2226 bandwidth when playing videos. Disabling adaptive encodings 2227 restores the original static behavior of encodings like Tight. 2228 2229 ``share=[allow-exclusive|force-shared|ignore]`` 2230 Set display sharing policy. 'allow-exclusive' allows clients to 2231 ask for exclusive access. As suggested by the rfb spec this is 2232 implemented by dropping other connections. Connecting multiple 2233 clients in parallel requires all clients asking for a shared 2234 session (vncviewer: -shared switch). This is the default. 2235 'force-shared' disables exclusive client access. Useful for 2236 shared desktop sessions, where you don't want someone forgetting 2237 specify -shared disconnect everybody else. 'ignore' completely 2238 ignores the shared flag and allows everybody connect 2239 unconditionally. Doesn't conform to the rfb spec but is 2240 traditional QEMU behavior. 2241 2242 ``key-delay-ms`` 2243 Set keyboard delay, for key down and key up events, in 2244 milliseconds. Default is 10. Keyboards are low-bandwidth 2245 devices, so this slowdown can help the device and guest to keep 2246 up and not lose events in case events are arriving in bulk. 2247 Possible causes for the latter are flaky network connections, or 2248 scripts for automated testing. 2249 2250 ``audiodev=audiodev`` 2251 Use the specified audiodev when the VNC client requests audio 2252 transmission. When not using an -audiodev argument, this option 2253 must be omitted, otherwise is must be present and specify a 2254 valid audiodev. 2255 2256 ``power-control`` 2257 Permit the remote client to issue shutdown, reboot or reset power 2258 control requests. 2259ERST 2260 2261ARCHHEADING(, QEMU_ARCH_I386) 2262 2263ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2264 2265DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2266 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2267 QEMU_ARCH_I386) 2268SRST 2269``-win2k-hack`` 2270 Use it when installing Windows 2000 to avoid a disk full bug. After 2271 Windows 2000 is installed, you no longer need this option (this 2272 option slows down the IDE transfers). 2273ERST 2274 2275DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2276 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2277 QEMU_ARCH_I386) 2278SRST 2279``-no-fd-bootchk`` 2280 Disable boot signature checking for floppy disks in BIOS. May be 2281 needed to boot from old floppy disks. 2282ERST 2283 2284DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2285 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2286SRST 2287``-no-acpi`` 2288 Disable ACPI (Advanced Configuration and Power Interface) support. 2289 Use it if your guest OS complains about ACPI problems (PC target 2290 machine only). 2291ERST 2292 2293DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2294 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2295SRST 2296``-no-hpet`` 2297 Disable HPET support. 2298ERST 2299 2300DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2301 "-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" 2302 " ACPI table description\n", QEMU_ARCH_I386) 2303SRST 2304``-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]...]`` 2305 Add ACPI table with specified header fields and context from 2306 specified files. For file=, take whole ACPI table from the specified 2307 files, including all ACPI headers (possible overridden by other 2308 options). For data=, only data portion of the table is used, all 2309 header information is specified in the command line. If a SLIC table 2310 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2311 fields will override the same in the RSDT and the FADT (a.k.a. 2312 FACP), in order to ensure the field matches required by the 2313 Microsoft SLIC spec and the ACPI spec. 2314ERST 2315 2316DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2317 "-smbios file=binary\n" 2318 " load SMBIOS entry from binary file\n" 2319 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2320 " [,uefi=on|off]\n" 2321 " specify SMBIOS type 0 fields\n" 2322 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2323 " [,uuid=uuid][,sku=str][,family=str]\n" 2324 " specify SMBIOS type 1 fields\n" 2325 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2326 " [,asset=str][,location=str]\n" 2327 " specify SMBIOS type 2 fields\n" 2328 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2329 " [,sku=str]\n" 2330 " specify SMBIOS type 3 fields\n" 2331 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2332 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2333 " specify SMBIOS type 4 fields\n" 2334 "-smbios type=11[,value=str][,path=filename]\n" 2335 " specify SMBIOS type 11 fields\n" 2336 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2337 " [,asset=str][,part=str][,speed=%d]\n" 2338 " specify SMBIOS type 17 fields\n", 2339 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2340SRST 2341``-smbios file=binary`` 2342 Load SMBIOS entry from binary file. 2343 2344``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2345 Specify SMBIOS type 0 fields 2346 2347``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2348 Specify SMBIOS type 1 fields 2349 2350``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2351 Specify SMBIOS type 2 fields 2352 2353``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2354 Specify SMBIOS type 3 fields 2355 2356``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2357 Specify SMBIOS type 4 fields 2358 2359``-smbios type=11[,value=str][,path=filename]`` 2360 Specify SMBIOS type 11 fields 2361 2362 This argument can be repeated multiple times, and values are added in the order they are parsed. 2363 Applications intending to use OEM strings data are encouraged to use their application name as 2364 a prefix for the value string. This facilitates passing information for multiple applications 2365 concurrently. 2366 2367 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2368 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2369 2370 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2371 the SMBIOS table in the order in which they appear. 2372 2373 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2374 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2375 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2376 data set, for example, by specifying the serial ID of a block device. 2377 2378 An example passing three strings is 2379 2380 .. parsed-literal:: 2381 2382 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2383 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2384 path=/some/file/with/oemstringsdata.txt 2385 2386 In the guest OS this is visible with the ``dmidecode`` command 2387 2388 .. parsed-literal:: 2389 2390 $ dmidecode -t 11 2391 Handle 0x0E00, DMI type 11, 5 bytes 2392 OEM Strings 2393 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2394 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2395 String 3: myapp:some extra data 2396 2397 2398``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2399 Specify SMBIOS type 17 fields 2400ERST 2401 2402DEFHEADING() 2403 2404DEFHEADING(Network options:) 2405 2406DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2407#ifdef CONFIG_SLIRP 2408 "-netdev user,id=str[,ipv4[=on|off]][,net=addr[/mask]][,host=addr]\n" 2409 " [,ipv6[=on|off]][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2410 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2411 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2412 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2413#ifndef _WIN32 2414 "[,smb=dir[,smbserver=addr]]\n" 2415#endif 2416 " configure a user mode network backend with ID 'str',\n" 2417 " its DHCP server and optional services\n" 2418#endif 2419#ifdef _WIN32 2420 "-netdev tap,id=str,ifname=name\n" 2421 " configure a host TAP network backend with ID 'str'\n" 2422#else 2423 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2424 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2425 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2426 " [,poll-us=n]\n" 2427 " configure a host TAP network backend with ID 'str'\n" 2428 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2429 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2430 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2431 " to deconfigure it\n" 2432 " use '[down]script=no' to disable script execution\n" 2433 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2434 " configure it\n" 2435 " use 'fd=h' to connect to an already opened TAP interface\n" 2436 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2437 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2438 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2439 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2440 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2441 " use vhost=on to enable experimental in kernel accelerator\n" 2442 " (only has effect for virtio guests which use MSIX)\n" 2443 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2444 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2445 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2446 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2447 " use 'poll-us=n' to speciy the maximum number of microseconds that could be\n" 2448 " spent on busy polling for vhost net\n" 2449 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2450 " configure a host TAP network backend with ID 'str' that is\n" 2451 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2452 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2453#endif 2454#ifdef __linux__ 2455 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2456 " [,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]\n" 2457 " [,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]\n" 2458 " [,rxcookie=rxcookie][,offset=offset]\n" 2459 " configure a network backend with ID 'str' connected to\n" 2460 " an Ethernet over L2TPv3 pseudowire.\n" 2461 " Linux kernel 3.3+ as well as most routers can talk\n" 2462 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2463 " VM to a router and even VM to Host. It is a nearly-universal\n" 2464 " standard (RFC3931). Note - this implementation uses static\n" 2465 " pre-configured tunnels (same as the Linux kernel).\n" 2466 " use 'src=' to specify source address\n" 2467 " use 'dst=' to specify destination address\n" 2468 " use 'udp=on' to specify udp encapsulation\n" 2469 " use 'srcport=' to specify source udp port\n" 2470 " use 'dstport=' to specify destination udp port\n" 2471 " use 'ipv6=on' to force v6\n" 2472 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2473 " well as a weak security measure\n" 2474 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2475 " use 'txcookie=0x012345678' to specify a txcookie\n" 2476 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2477 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2478 " use 'pincounter=on' to work around broken counter handling in peer\n" 2479 " use 'offset=X' to add an extra offset between header and data\n" 2480#endif 2481 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2482 " configure a network backend to connect to another network\n" 2483 " using a socket connection\n" 2484 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2485 " configure a network backend to connect to a multicast maddr and port\n" 2486 " use 'localaddr=addr' to specify the host address to send packets from\n" 2487 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2488 " configure a network backend to connect to another network\n" 2489 " using an UDP tunnel\n" 2490#ifdef CONFIG_VDE 2491 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2492 " configure a network backend to connect to port 'n' of a vde switch\n" 2493 " running on host and listening for incoming connections on 'socketpath'.\n" 2494 " Use group 'groupname' and mode 'octalmode' to change default\n" 2495 " ownership and permissions for communication port.\n" 2496#endif 2497#ifdef CONFIG_NETMAP 2498 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2499 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2500 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2501 " netmap device, defaults to '/dev/netmap')\n" 2502#endif 2503#ifdef CONFIG_POSIX 2504 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2505 " configure a vhost-user network, backed by a chardev 'dev'\n" 2506#endif 2507#ifdef __linux__ 2508 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2509 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2510#endif 2511 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2512 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2513DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2514 "-nic [tap|bridge|" 2515#ifdef CONFIG_SLIRP 2516 "user|" 2517#endif 2518#ifdef __linux__ 2519 "l2tpv3|" 2520#endif 2521#ifdef CONFIG_VDE 2522 "vde|" 2523#endif 2524#ifdef CONFIG_NETMAP 2525 "netmap|" 2526#endif 2527#ifdef CONFIG_POSIX 2528 "vhost-user|" 2529#endif 2530 "socket][,option][,...][mac=macaddr]\n" 2531 " initialize an on-board / default host NIC (using MAC address\n" 2532 " macaddr) and connect it to the given host network backend\n" 2533 "-nic none use it alone to have zero network devices (the default is to\n" 2534 " provided a 'user' network connection)\n", 2535 QEMU_ARCH_ALL) 2536DEF("net", HAS_ARG, QEMU_OPTION_net, 2537 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2538 " configure or create an on-board (or machine default) NIC and\n" 2539 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2540 "-net [" 2541#ifdef CONFIG_SLIRP 2542 "user|" 2543#endif 2544 "tap|" 2545 "bridge|" 2546#ifdef CONFIG_VDE 2547 "vde|" 2548#endif 2549#ifdef CONFIG_NETMAP 2550 "netmap|" 2551#endif 2552 "socket][,option][,option][,...]\n" 2553 " old way to initialize a host network interface\n" 2554 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2555SRST 2556``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2557 This option is a shortcut for configuring both the on-board 2558 (default) guest NIC hardware and the host network backend in one go. 2559 The host backend options are the same as with the corresponding 2560 ``-netdev`` options below. The guest NIC model can be set with 2561 ``model=modelname``. Use ``model=help`` to list the available device 2562 types. The hardware MAC address can be set with ``mac=macaddr``. 2563 2564 The following two example do exactly the same, to show how ``-nic`` 2565 can be used to shorten the command line length: 2566 2567 .. parsed-literal:: 2568 2569 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2570 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2571 2572``-nic none`` 2573 Indicate that no network devices should be configured. It is used to 2574 override the default configuration (default NIC with "user" host 2575 network backend) which is activated if no other networking options 2576 are provided. 2577 2578``-netdev user,id=id[,option][,option][,...]`` 2579 Configure user mode host network backend which requires no 2580 administrator privilege to run. Valid options are: 2581 2582 ``id=id`` 2583 Assign symbolic name for use in monitor commands. 2584 2585 ``ipv4=on|off and ipv6=on|off`` 2586 Specify that either IPv4 or IPv6 must be enabled. If neither is 2587 specified both protocols are enabled. 2588 2589 ``net=addr[/mask]`` 2590 Set IP network address the guest will see. Optionally specify 2591 the netmask, either in the form a.b.c.d or as number of valid 2592 top-most bits. Default is 10.0.2.0/24. 2593 2594 ``host=addr`` 2595 Specify the guest-visible address of the host. Default is the 2596 2nd IP in the guest network, i.e. x.x.x.2. 2597 2598 ``ipv6-net=addr[/int]`` 2599 Set IPv6 network address the guest will see (default is 2600 fec0::/64). The network prefix is given in the usual hexadecimal 2601 IPv6 address notation. The prefix size is optional, and is given 2602 as the number of valid top-most bits (default is 64). 2603 2604 ``ipv6-host=addr`` 2605 Specify the guest-visible IPv6 address of the host. Default is 2606 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2607 2608 ``restrict=on|off`` 2609 If this option is enabled, the guest will be isolated, i.e. it 2610 will not be able to contact the host and no guest IP packets 2611 will be routed over the host to the outside. This option does 2612 not affect any explicitly set forwarding rules. 2613 2614 ``hostname=name`` 2615 Specifies the client hostname reported by the built-in DHCP 2616 server. 2617 2618 ``dhcpstart=addr`` 2619 Specify the first of the 16 IPs the built-in DHCP server can 2620 assign. Default is the 15th to 31st IP in the guest network, 2621 i.e. x.x.x.15 to x.x.x.31. 2622 2623 ``dns=addr`` 2624 Specify the guest-visible address of the virtual nameserver. The 2625 address must be different from the host address. Default is the 2626 3rd IP in the guest network, i.e. x.x.x.3. 2627 2628 ``ipv6-dns=addr`` 2629 Specify the guest-visible address of the IPv6 virtual 2630 nameserver. The address must be different from the host address. 2631 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2632 2633 ``dnssearch=domain`` 2634 Provides an entry for the domain-search list sent by the 2635 built-in DHCP server. More than one domain suffix can be 2636 transmitted by specifying this option multiple times. If 2637 supported, this will cause the guest to automatically try to 2638 append the given domain suffix(es) in case a domain name can not 2639 be resolved. 2640 2641 Example: 2642 2643 .. parsed-literal:: 2644 2645 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2646 2647 ``domainname=domain`` 2648 Specifies the client domain name reported by the built-in DHCP 2649 server. 2650 2651 ``tftp=dir`` 2652 When using the user mode network stack, activate a built-in TFTP 2653 server. The files in dir will be exposed as the root of a TFTP 2654 server. The TFTP client on the guest must be configured in 2655 binary mode (use the command ``bin`` of the Unix TFTP client). 2656 2657 ``tftp-server-name=name`` 2658 In BOOTP reply, broadcast name as the "TFTP server name" 2659 (RFC2132 option 66). This can be used to advise the guest to 2660 load boot files or configurations from a different server than 2661 the host address. 2662 2663 ``bootfile=file`` 2664 When using the user mode network stack, broadcast file as the 2665 BOOTP filename. In conjunction with ``tftp``, this can be used 2666 to network boot a guest from a local directory. 2667 2668 Example (using pxelinux): 2669 2670 .. parsed-literal:: 2671 2672 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2673 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2674 2675 ``smb=dir[,smbserver=addr]`` 2676 When using the user mode network stack, activate a built-in SMB 2677 server so that Windows OSes can access to the host files in 2678 ``dir`` transparently. The IP address of the SMB server can be 2679 set to addr. By default the 4th IP in the guest network is used, 2680 i.e. x.x.x.4. 2681 2682 In the guest Windows OS, the line: 2683 2684 :: 2685 2686 10.0.2.4 smbserver 2687 2688 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2689 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2690 NT/2000). 2691 2692 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2693 2694 Note that a SAMBA server must be installed on the host OS. 2695 2696 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2697 Redirect incoming TCP or UDP connections to the host port 2698 hostport to the guest IP address guestaddr on guest port 2699 guestport. If guestaddr is not specified, its value is x.x.x.15 2700 (default first address given by the built-in DHCP server). By 2701 specifying hostaddr, the rule can be bound to a specific host 2702 interface. If no connection type is set, TCP is used. This 2703 option can be given multiple times. 2704 2705 For example, to redirect host X11 connection from screen 1 to 2706 guest screen 0, use the following: 2707 2708 .. parsed-literal:: 2709 2710 # on the host 2711 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2712 # this host xterm should open in the guest X11 server 2713 xterm -display :1 2714 2715 To redirect telnet connections from host port 5555 to telnet 2716 port on the guest, use the following: 2717 2718 .. parsed-literal:: 2719 2720 # on the host 2721 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2722 telnet localhost 5555 2723 2724 Then when you use on the host ``telnet localhost 5555``, you 2725 connect to the guest telnet server. 2726 2727 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2728 Forward guest TCP connections to the IP address server on port 2729 port to the character device dev or to a program executed by 2730 cmd:command which gets spawned for each connection. This option 2731 can be given multiple times. 2732 2733 You can either use a chardev directly and have that one used 2734 throughout QEMU's lifetime, like in the following example: 2735 2736 .. parsed-literal:: 2737 2738 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2739 # the guest accesses it 2740 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2741 2742 Or you can execute a command on every TCP connection established 2743 by the guest, so that QEMU behaves similar to an inetd process 2744 for that virtual server: 2745 2746 .. parsed-literal:: 2747 2748 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2749 # and connect the TCP stream to its stdin/stdout 2750 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2751 2752``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2753 Configure a host TAP network backend with ID id. 2754 2755 Use the network script file to configure it and the network script 2756 dfile to deconfigure it. If name is not provided, the OS 2757 automatically provides one. The default network configure script is 2758 ``/etc/qemu-ifup`` and the default network deconfigure script is 2759 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2760 disable script execution. 2761 2762 If running QEMU as an unprivileged user, use the network helper 2763 to configure the TAP interface and attach it to the bridge. 2764 The default network helper executable is 2765 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2766 ``br0``. 2767 2768 ``fd``\ =h can be used to specify the handle of an already opened 2769 host TAP interface. 2770 2771 Examples: 2772 2773 .. parsed-literal:: 2774 2775 #launch a QEMU instance with the default network script 2776 |qemu_system| linux.img -nic tap 2777 2778 .. parsed-literal:: 2779 2780 #launch a QEMU instance with two NICs, each one connected 2781 #to a TAP device 2782 |qemu_system| linux.img \\ 2783 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2784 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2785 2786 .. parsed-literal:: 2787 2788 #launch a QEMU instance with the default network helper to 2789 #connect a TAP device to bridge br0 2790 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2791 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2792 2793``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2794 Connect a host TAP network interface to a host bridge device. 2795 2796 Use the network helper helper to configure the TAP interface and 2797 attach it to the bridge. The default network helper executable is 2798 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2799 ``br0``. 2800 2801 Examples: 2802 2803 .. parsed-literal:: 2804 2805 #launch a QEMU instance with the default network helper to 2806 #connect a TAP device to bridge br0 2807 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2808 2809 .. parsed-literal:: 2810 2811 #launch a QEMU instance with the default network helper to 2812 #connect a TAP device to bridge qemubr0 2813 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2814 2815``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2816 This host network backend can be used to connect the guest's network 2817 to another QEMU virtual machine using a TCP socket connection. If 2818 ``listen`` is specified, QEMU waits for incoming connections on port 2819 (host is optional). ``connect`` is used to connect to another QEMU 2820 instance using the ``listen`` option. ``fd``\ =h specifies an 2821 already opened TCP socket. 2822 2823 Example: 2824 2825 .. parsed-literal:: 2826 2827 # launch a first QEMU instance 2828 |qemu_system| linux.img \\ 2829 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2830 -netdev socket,id=n1,listen=:1234 2831 # connect the network of this instance to the network of the first instance 2832 |qemu_system| linux.img \\ 2833 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2834 -netdev socket,id=n2,connect=127.0.0.1:1234 2835 2836``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2837 Configure a socket host network backend to share the guest's network 2838 traffic with another QEMU virtual machines using a UDP multicast 2839 socket, effectively making a bus for every QEMU with same multicast 2840 address maddr and port. NOTES: 2841 2842 1. Several QEMU can be running on different hosts and share same bus 2843 (assuming correct multicast setup for these hosts). 2844 2845 2. mcast support is compatible with User Mode Linux (argument 2846 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2847 2848 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2849 2850 Example: 2851 2852 .. parsed-literal:: 2853 2854 # launch one QEMU instance 2855 |qemu_system| linux.img \\ 2856 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2857 -netdev socket,id=n1,mcast=230.0.0.1:1234 2858 # launch another QEMU instance on same "bus" 2859 |qemu_system| linux.img \\ 2860 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2861 -netdev socket,id=n2,mcast=230.0.0.1:1234 2862 # launch yet another QEMU instance on same "bus" 2863 |qemu_system| linux.img \\ 2864 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2865 -netdev socket,id=n3,mcast=230.0.0.1:1234 2866 2867 Example (User Mode Linux compat.): 2868 2869 .. parsed-literal:: 2870 2871 # launch QEMU instance (note mcast address selected is UML's default) 2872 |qemu_system| linux.img \\ 2873 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2874 -netdev socket,id=n1,mcast=239.192.168.1:1102 2875 # launch UML 2876 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2877 2878 Example (send packets from host's 1.2.3.4): 2879 2880 .. parsed-literal:: 2881 2882 |qemu_system| linux.img \\ 2883 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2884 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2885 2886``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6][,udp][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2887 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2888 is a popular protocol to transport Ethernet (and other Layer 2) data 2889 frames between two systems. It is present in routers, firewalls and 2890 the Linux kernel (from version 3.3 onwards). 2891 2892 This transport allows a VM to communicate to another VM, router or 2893 firewall directly. 2894 2895 ``src=srcaddr`` 2896 source address (mandatory) 2897 2898 ``dst=dstaddr`` 2899 destination address (mandatory) 2900 2901 ``udp`` 2902 select udp encapsulation (default is ip). 2903 2904 ``srcport=srcport`` 2905 source udp port. 2906 2907 ``dstport=dstport`` 2908 destination udp port. 2909 2910 ``ipv6`` 2911 force v6, otherwise defaults to v4. 2912 2913 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2914 Cookies are a weak form of security in the l2tpv3 specification. 2915 Their function is mostly to prevent misconfiguration. By default 2916 they are 32 bit. 2917 2918 ``cookie64`` 2919 Set cookie size to 64 bit instead of the default 32 2920 2921 ``counter=off`` 2922 Force a 'cut-down' L2TPv3 with no counter as in 2923 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2924 2925 ``pincounter=on`` 2926 Work around broken counter handling in peer. This may also help 2927 on networks which have packet reorder. 2928 2929 ``offset=offset`` 2930 Add an extra offset between header and data 2931 2932 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 2933 the bridge br-lan on the remote Linux host 1.2.3.4: 2934 2935 .. parsed-literal:: 2936 2937 # Setup tunnel on linux host using raw ip as encapsulation 2938 # on 1.2.3.4 2939 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 2940 encap udp udp_sport 16384 udp_dport 16384 2941 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 2942 0xFFFFFFFF peer_session_id 0xFFFFFFFF 2943 ifconfig vmtunnel0 mtu 1500 2944 ifconfig vmtunnel0 up 2945 brctl addif br-lan vmtunnel0 2946 2947 2948 # on 4.3.2.1 2949 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 2950 2951 |qemu_system| linux.img -device e1000,netdev=n1 \\ 2952 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 2953 2954``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 2955 Configure VDE backend to connect to PORT n of a vde switch running 2956 on host and listening for incoming connections on socketpath. Use 2957 GROUP groupname and MODE octalmode to change default ownership and 2958 permissions for communication port. This option is only available if 2959 QEMU has been compiled with vde support enabled. 2960 2961 Example: 2962 2963 .. parsed-literal:: 2964 2965 # launch vde switch 2966 vde_switch -F -sock /tmp/myswitch 2967 # launch QEMU instance 2968 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 2969 2970``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 2971 Establish a vhost-user netdev, backed by a chardev id. The chardev 2972 should be a unix domain socket backed one. The vhost-user uses a 2973 specifically defined protocol to pass vhost ioctl replacement 2974 messages to an application on the other end of the socket. On 2975 non-MSIX guests, the feature can be forced with vhostforce. Use 2976 'queues=n' to specify the number of queues to be created for 2977 multiqueue vhost-user. 2978 2979 Example: 2980 2981 :: 2982 2983 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 2984 -numa node,memdev=mem \ 2985 -chardev socket,id=chr0,path=/path/to/socket \ 2986 -netdev type=vhost-user,id=net0,chardev=chr0 \ 2987 -device virtio-net-pci,netdev=net0 2988 2989``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 2990 Establish a vhost-vdpa netdev. 2991 2992 vDPA device is a device that uses a datapath which complies with 2993 the virtio specifications with a vendor specific control path. 2994 vDPA devices can be both physically located on the hardware or 2995 emulated by software. 2996 2997``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 2998 Create a hub port on the emulated hub with ID hubid. 2999 3000 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3001 instead of a single netdev. Alternatively, you can also connect the 3002 hubport to another netdev with ID nd by using the ``netdev=nd`` 3003 option. 3004 3005``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3006 Legacy option to configure or create an on-board (or machine 3007 default) Network Interface Card(NIC) and connect it either to the 3008 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3009 If model is omitted, then the default NIC model associated with the 3010 machine type is used. Note that the default NIC model may change in 3011 future QEMU releases, so it is highly recommended to always specify 3012 a model. Optionally, the MAC address can be changed to mac, the 3013 device address set to addr (PCI cards only), and a name can be 3014 assigned for use in monitor commands. Optionally, for PCI cards, you 3015 can specify the number v of MSI-X vectors that the card should have; 3016 this option currently only affects virtio cards; set v = 0 to 3017 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3018 created. QEMU can emulate several different models of network card. 3019 Use ``-net nic,model=help`` for a list of available devices for your 3020 target. 3021 3022``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3023 Configure a host network backend (with the options corresponding to 3024 the same ``-netdev`` option) and connect it to the emulated hub 0 3025 (the default hub). Use name to specify the name of the hub port. 3026ERST 3027 3028DEFHEADING() 3029 3030DEFHEADING(Character device options:) 3031 3032DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3033 "-chardev help\n" 3034 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3035 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n" 3036 " [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n" 3037 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3038 "-chardev socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,reconnect=seconds]\n" 3039 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3040 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3041 " [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n" 3042 " [,logfile=PATH][,logappend=on|off]\n" 3043 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3044 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3045 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3046 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3047 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3048 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3049#ifdef _WIN32 3050 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3051 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3052#else 3053 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3054 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3055#endif 3056#ifdef CONFIG_BRLAPI 3057 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3058#endif 3059#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3060 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3061 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3062 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3063#endif 3064#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3065 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3066 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3067#endif 3068#if defined(CONFIG_SPICE) 3069 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3070 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3071#endif 3072 , QEMU_ARCH_ALL 3073) 3074 3075SRST 3076The general form of a character device option is: 3077 3078``-chardev backend,id=id[,mux=on|off][,options]`` 3079 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3080 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3081 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3082 ``spicevmc``, ``spiceport``. The specific backend will determine the 3083 applicable options. 3084 3085 Use ``-chardev help`` to print all available chardev backend types. 3086 3087 All devices must have an id, which can be any string up to 127 3088 characters long. It is used to uniquely identify this device in 3089 other command line directives. 3090 3091 A character device may be used in multiplexing mode by multiple 3092 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3093 a "1:N" device, and here the "1" end is your specified chardev 3094 backend, and the "N" end is the various parts of QEMU that can talk 3095 to a chardev. If you create a chardev with ``id=myid`` and 3096 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3097 and you can then configure multiple front ends to use that chardev 3098 ID for their input/output. Up to four different front ends can be 3099 connected to a single multiplexed chardev. (Without multiplexing 3100 enabled, a chardev can only be used by a single front end.) For 3101 instance you could use this to allow a single stdio chardev to be 3102 used by two serial ports and the QEMU monitor: 3103 3104 :: 3105 3106 -chardev stdio,mux=on,id=char0 \ 3107 -mon chardev=char0,mode=readline \ 3108 -serial chardev:char0 \ 3109 -serial chardev:char0 3110 3111 You can have more than one multiplexer in a system configuration; 3112 for instance you could have a TCP port multiplexed between UART 0 3113 and UART 1, and stdio multiplexed between the QEMU monitor and a 3114 parallel port: 3115 3116 :: 3117 3118 -chardev stdio,mux=on,id=char0 \ 3119 -mon chardev=char0,mode=readline \ 3120 -parallel chardev:char0 \ 3121 -chardev tcp,...,mux=on,id=char1 \ 3122 -serial chardev:char1 \ 3123 -serial chardev:char1 3124 3125 When you're using a multiplexed character device, some escape 3126 sequences are interpreted in the input. See the chapter about 3127 :ref:`keys in the character backend multiplexer` in the 3128 System Emulation Users Guide for more details. 3129 3130 Note that some other command line options may implicitly create 3131 multiplexed character backends; for instance ``-serial mon:stdio`` 3132 creates a multiplexed stdio backend connected to the serial port and 3133 the QEMU monitor, and ``-nographic`` also multiplexes the console 3134 and the monitor to stdio. 3135 3136 There is currently no support for multiplexing in the other 3137 direction (where a single QEMU front end takes input and output from 3138 multiple chardevs). 3139 3140 Every backend supports the ``logfile`` option, which supplies the 3141 path to a file to record all data transmitted via the backend. The 3142 ``logappend`` option controls whether the log file will be truncated 3143 or appended to when opened. 3144 3145The available backends are: 3146 3147``-chardev null,id=id`` 3148 A void device. This device will not emit any data, and will drop any 3149 data it receives. The null backend does not take any options. 3150 3151``-chardev socket,id=id[,TCP options or unix options][,server][,nowait][,telnet][,websocket][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3152 Create a two-way stream socket, which can be either a TCP or a unix 3153 socket. A unix socket will be created if ``path`` is specified. 3154 Behaviour is undefined if TCP options are specified for a unix 3155 socket. 3156 3157 ``server`` specifies that the socket shall be a listening socket. 3158 3159 ``nowait`` specifies that QEMU should not block waiting for a client 3160 to connect to a listening socket. 3161 3162 ``telnet`` specifies that traffic on the socket should interpret 3163 telnet escape sequences. 3164 3165 ``websocket`` specifies that the socket uses WebSocket protocol for 3166 communication. 3167 3168 ``reconnect`` sets the timeout for reconnecting on non-server 3169 sockets when the remote end goes away. qemu will delay this many 3170 seconds and then attempt to reconnect. Zero disables reconnecting, 3171 and is the default. 3172 3173 ``tls-creds`` requests enablement of the TLS protocol for 3174 encryption, and specifies the id of the TLS credentials to use for 3175 the handshake. The credentials must be previously created with the 3176 ``-object tls-creds`` argument. 3177 3178 ``tls-auth`` provides the ID of the QAuthZ authorization object 3179 against which the client's x509 distinguished name will be 3180 validated. This object is only resolved at time of use, so can be 3181 deleted and recreated on the fly while the chardev server is active. 3182 If missing, it will default to denying access. 3183 3184 TCP and unix socket options are given below: 3185 3186 ``TCP options: port=port[,host=host][,to=to][,ipv4][,ipv6][,nodelay]`` 3187 ``host`` for a listening socket specifies the local address to 3188 be bound. For a connecting socket species the remote host to 3189 connect to. ``host`` is optional for listening sockets. If not 3190 specified it defaults to ``0.0.0.0``. 3191 3192 ``port`` for a listening socket specifies the local port to be 3193 bound. For a connecting socket specifies the port on the remote 3194 host to connect to. ``port`` can be given as either a port 3195 number or a service name. ``port`` is required. 3196 3197 ``to`` is only relevant to listening sockets. If it is 3198 specified, and ``port`` cannot be bound, QEMU will attempt to 3199 bind to subsequent ports up to and including ``to`` until it 3200 succeeds. ``to`` must be specified as a port number. 3201 3202 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be 3203 used. If neither is specified the socket may use either 3204 protocol. 3205 3206 ``nodelay`` disables the Nagle algorithm. 3207 3208 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3209 ``path`` specifies the local path of the unix socket. ``path`` 3210 is required. 3211 ``abstract`` specifies the use of the abstract socket namespace, 3212 rather than the filesystem. Optional, defaults to false. 3213 ``tight`` sets the socket length of abstract sockets to their minimum, 3214 rather than the full sun_path length. Optional, defaults to true. 3215 3216``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4][,ipv6]`` 3217 Sends all traffic from the guest to a remote host over UDP. 3218 3219 ``host`` specifies the remote host to connect to. If not specified 3220 it defaults to ``localhost``. 3221 3222 ``port`` specifies the port on the remote host to connect to. 3223 ``port`` is required. 3224 3225 ``localaddr`` specifies the local address to bind to. If not 3226 specified it defaults to ``0.0.0.0``. 3227 3228 ``localport`` specifies the local port to bind to. If not specified 3229 any available local port will be used. 3230 3231 ``ipv4`` and ``ipv6`` specify that either IPv4 or IPv6 must be used. 3232 If neither is specified the device may use either protocol. 3233 3234``-chardev msmouse,id=id`` 3235 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3236 does not take any options. 3237 3238``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3239 Connect to a QEMU text console. ``vc`` may optionally be given a 3240 specific size. 3241 3242 ``width`` and ``height`` specify the width and height respectively 3243 of the console, in pixels. 3244 3245 ``cols`` and ``rows`` specify that the console be sized to fit a 3246 text console with the given dimensions. 3247 3248``-chardev ringbuf,id=id[,size=size]`` 3249 Create a ring buffer with fixed size ``size``. size must be a power 3250 of two and defaults to ``64K``. 3251 3252``-chardev file,id=id,path=path`` 3253 Log all traffic received from the guest to a file. 3254 3255 ``path`` specifies the path of the file to be opened. This file will 3256 be created if it does not already exist, and overwritten if it does. 3257 ``path`` is required. 3258 3259``-chardev pipe,id=id,path=path`` 3260 Create a two-way connection to the guest. The behaviour differs 3261 slightly between Windows hosts and other hosts: 3262 3263 On Windows, a single duplex pipe will be created at 3264 ``\\.pipe\path``. 3265 3266 On other hosts, 2 pipes will be created called ``path.in`` and 3267 ``path.out``. Data written to ``path.in`` will be received by the 3268 guest. Data written by the guest can be read from ``path.out``. QEMU 3269 will not create these fifos, and requires them to be present. 3270 3271 ``path`` forms part of the pipe path as described above. ``path`` is 3272 required. 3273 3274``-chardev console,id=id`` 3275 Send traffic from the guest to QEMU's standard output. ``console`` 3276 does not take any options. 3277 3278 ``console`` is only available on Windows hosts. 3279 3280``-chardev serial,id=id,path=path`` 3281 Send traffic from the guest to a serial device on the host. 3282 3283 On Unix hosts serial will actually accept any tty device, not only 3284 serial lines. 3285 3286 ``path`` specifies the name of the serial device to open. 3287 3288``-chardev pty,id=id`` 3289 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3290 does not take any options. 3291 3292 ``pty`` is not available on Windows hosts. 3293 3294``-chardev stdio,id=id[,signal=on|off]`` 3295 Connect to standard input and standard output of the QEMU process. 3296 3297 ``signal`` controls if signals are enabled on the terminal, that 3298 includes exiting QEMU with the key sequence Control-c. This option 3299 is enabled by default, use ``signal=off`` to disable it. 3300 3301``-chardev braille,id=id`` 3302 Connect to a local BrlAPI server. ``braille`` does not take any 3303 options. 3304 3305``-chardev tty,id=id,path=path`` 3306 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3307 and DragonFlyBSD hosts. It is an alias for ``serial``. 3308 3309 ``path`` specifies the path to the tty. ``path`` is required. 3310 3311``-chardev parallel,id=id,path=path`` 3312 \ 3313``-chardev parport,id=id,path=path`` 3314 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3315 hosts. 3316 3317 Connect to a local parallel port. 3318 3319 ``path`` specifies the path to the parallel port device. ``path`` is 3320 required. 3321 3322``-chardev spicevmc,id=id,debug=debug,name=name`` 3323 ``spicevmc`` is only available when spice support is built in. 3324 3325 ``debug`` debug level for spicevmc 3326 3327 ``name`` name of spice channel to connect to 3328 3329 Connect to a spice virtual machine channel, such as vdiport. 3330 3331``-chardev spiceport,id=id,debug=debug,name=name`` 3332 ``spiceport`` is only available when spice support is built in. 3333 3334 ``debug`` debug level for spicevmc 3335 3336 ``name`` name of spice port to connect to 3337 3338 Connect to a spice port, allowing a Spice client to handle the 3339 traffic identified by a name (preferably a fqdn). 3340ERST 3341 3342DEFHEADING() 3343 3344#ifdef CONFIG_TPM 3345DEFHEADING(TPM device options:) 3346 3347DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3348 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3349 " use path to provide path to a character device; default is /dev/tpm0\n" 3350 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3351 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3352 "-tpmdev emulator,id=id,chardev=dev\n" 3353 " configure the TPM device using chardev backend\n", 3354 QEMU_ARCH_ALL) 3355SRST 3356The general form of a TPM device option is: 3357 3358``-tpmdev backend,id=id[,options]`` 3359 The specific backend type will determine the applicable options. The 3360 ``-tpmdev`` option creates the TPM backend and requires a 3361 ``-device`` option that specifies the TPM frontend interface model. 3362 3363 Use ``-tpmdev help`` to print all available TPM backend types. 3364 3365The available backends are: 3366 3367``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3368 (Linux-host only) Enable access to the host's TPM using the 3369 passthrough driver. 3370 3371 ``path`` specifies the path to the host's TPM device, i.e., on a 3372 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3373 default ``/dev/tpm0`` is used. 3374 3375 ``cancel-path`` specifies the path to the host TPM device's sysfs 3376 entry allowing for cancellation of an ongoing TPM command. 3377 ``cancel-path`` is optional and by default QEMU will search for the 3378 sysfs entry to use. 3379 3380 Some notes about using the host's TPM with the passthrough driver: 3381 3382 The TPM device accessed by the passthrough driver must not be used 3383 by any other application on the host. 3384 3385 Since the host's firmware (BIOS/UEFI) has already initialized the 3386 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3387 the TPM again and may therefore not show a TPM-specific menu that 3388 would otherwise allow the user to configure the TPM, e.g., allow the 3389 user to enable/disable or activate/deactivate the TPM. Further, if 3390 TPM ownership is released from within a VM then the host's TPM will 3391 get disabled and deactivated. To enable and activate the TPM again 3392 afterwards, the host has to be rebooted and the user is required to 3393 enter the firmware's menu to enable and activate the TPM. If the TPM 3394 is left disabled and/or deactivated most TPM commands will fail. 3395 3396 To create a passthrough TPM use the following two options: 3397 3398 :: 3399 3400 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3401 3402 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3403 ``tpmdev=tpm0`` in the device option. 3404 3405``-tpmdev emulator,id=id,chardev=dev`` 3406 (Linux-host only) Enable access to a TPM emulator using Unix domain 3407 socket based chardev backend. 3408 3409 ``chardev`` specifies the unique ID of a character device backend 3410 that provides connection to the software TPM server. 3411 3412 To create a TPM emulator backend device with chardev socket backend: 3413 3414 :: 3415 3416 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3417ERST 3418 3419DEFHEADING() 3420 3421#endif 3422 3423DEFHEADING(Linux/Multiboot boot specific:) 3424SRST 3425When using these options, you can use a given Linux or Multiboot kernel 3426without installing it in the disk image. It can be useful for easier 3427testing of various kernels. 3428 3429 3430ERST 3431 3432DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3433 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3434SRST 3435``-kernel bzImage`` 3436 Use bzImage as kernel image. The kernel can be either a Linux kernel 3437 or in multiboot format. 3438ERST 3439 3440DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3441 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3442SRST 3443``-append cmdline`` 3444 Use cmdline as kernel command line 3445ERST 3446 3447DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3448 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3449SRST 3450``-initrd file`` 3451 Use file as initial ram disk. 3452 3453``-initrd "file1 arg=foo,file2"`` 3454 This syntax is only available with multiboot. 3455 3456 Use file1 and file2 as modules and pass arg=foo as parameter to the 3457 first module. 3458ERST 3459 3460DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3461 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3462SRST 3463``-dtb file`` 3464 Use file as a device tree binary (dtb) image and pass it to the 3465 kernel on boot. 3466ERST 3467 3468DEFHEADING() 3469 3470DEFHEADING(Debug/Expert options:) 3471 3472DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3473 "-fw_cfg [name=]<name>,file=<file>\n" 3474 " add named fw_cfg entry with contents from file\n" 3475 "-fw_cfg [name=]<name>,string=<str>\n" 3476 " add named fw_cfg entry with contents from string\n", 3477 QEMU_ARCH_ALL) 3478SRST 3479``-fw_cfg [name=]name,file=file`` 3480 Add named fw\_cfg entry with contents from file file. 3481 3482``-fw_cfg [name=]name,string=str`` 3483 Add named fw\_cfg entry with contents from string str. 3484 3485 The terminating NUL character of the contents of str will not be 3486 included as part of the fw\_cfg item data. To insert contents with 3487 embedded NUL characters, you have to use the file parameter. 3488 3489 The fw\_cfg entries are passed by QEMU through to the guest. 3490 3491 Example: 3492 3493 :: 3494 3495 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3496 3497 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3498 from ./my\_blob.bin. 3499ERST 3500 3501DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3502 "-serial dev redirect the serial port to char device 'dev'\n", 3503 QEMU_ARCH_ALL) 3504SRST 3505``-serial dev`` 3506 Redirect the virtual serial port to host character device dev. The 3507 default device is ``vc`` in graphical mode and ``stdio`` in non 3508 graphical mode. 3509 3510 This option can be used several times to simulate up to 4 serial 3511 ports. 3512 3513 Use ``-serial none`` to disable all serial ports. 3514 3515 Available character devices are: 3516 3517 ``vc[:WxH]`` 3518 Virtual console. Optionally, a width and height can be given in 3519 pixel with 3520 3521 :: 3522 3523 vc:800x600 3524 3525 It is also possible to specify width or height in characters: 3526 3527 :: 3528 3529 vc:80Cx24C 3530 3531 ``pty`` 3532 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3533 3534 ``none`` 3535 No device is allocated. 3536 3537 ``null`` 3538 void device 3539 3540 ``chardev:id`` 3541 Use a named character device defined with the ``-chardev`` 3542 option. 3543 3544 ``/dev/XXX`` 3545 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3546 port parameters are set according to the emulated ones. 3547 3548 ``/dev/parportN`` 3549 [Linux only, parallel port only] Use host parallel port N. 3550 Currently SPP and EPP parallel port features can be used. 3551 3552 ``file:filename`` 3553 Write output to filename. No character can be read. 3554 3555 ``stdio`` 3556 [Unix only] standard input/output 3557 3558 ``pipe:filename`` 3559 name pipe filename 3560 3561 ``COMn`` 3562 [Windows only] Use host serial port n 3563 3564 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3565 This implements UDP Net Console. When remote\_host or src\_ip 3566 are not specified they default to ``0.0.0.0``. When not using a 3567 specified src\_port a random port is automatically chosen. 3568 3569 If you just want a simple readonly console you can use 3570 ``netcat`` or ``nc``, by starting QEMU with: 3571 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3572 QEMU writes something to that port it will appear in the 3573 netconsole session. 3574 3575 If you plan to send characters back via netconsole or you want 3576 to stop and start QEMU a lot of times, you should have QEMU use 3577 the same source port each time by using something like ``-serial 3578 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3579 version of netcat which can listen to a TCP port and send and 3580 receive characters via udp. If you have a patched version of 3581 netcat which activates telnet remote echo and single char 3582 transfer, then you can use the following options to set up a 3583 netcat redirector to allow telnet on port 5555 to access the 3584 QEMU port. 3585 3586 ``QEMU Options:`` 3587 -serial udp::4555@:4556 3588 3589 ``netcat options:`` 3590 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3591 3592 ``telnet options:`` 3593 localhost 5555 3594 3595 ``tcp:[host]:port[,server][,nowait][,nodelay][,reconnect=seconds]`` 3596 The TCP Net Console has two modes of operation. It can send the 3597 serial I/O to a location or wait for a connection from a 3598 location. By default the TCP Net Console is sent to host at the 3599 port. If you use the server option QEMU will wait for a client 3600 socket application to connect to the port before continuing, 3601 unless the ``nowait`` option was specified. The ``nodelay`` 3602 option disables the Nagle buffering algorithm. The ``reconnect`` 3603 option only applies if noserver is set, if the connection goes 3604 down it will attempt to reconnect at the given interval. If host 3605 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3606 time is accepted. You can use ``telnet`` to connect to the 3607 corresponding character device. 3608 3609 ``Example to send tcp console to 192.168.0.2 port 4444`` 3610 -serial tcp:192.168.0.2:4444 3611 3612 ``Example to listen and wait on port 4444 for connection`` 3613 -serial tcp::4444,server 3614 3615 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3616 -serial tcp:192.168.0.100:4444,server,nowait 3617 3618 ``telnet:host:port[,server][,nowait][,nodelay]`` 3619 The telnet protocol is used instead of raw tcp sockets. The 3620 options work the same as if you had specified ``-serial tcp``. 3621 The difference is that the port acts like a telnet server or 3622 client using telnet option negotiation. This will also allow you 3623 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3624 supports sending the break sequence. Typically in unix telnet 3625 you do it with Control-] and then type "send break" followed by 3626 pressing the enter key. 3627 3628 ``websocket:host:port,server[,nowait][,nodelay]`` 3629 The WebSocket protocol is used instead of raw tcp socket. The 3630 port acts as a WebSocket server. Client mode is not supported. 3631 3632 ``unix:path[,server][,nowait][,reconnect=seconds]`` 3633 A unix domain socket is used instead of a tcp socket. The option 3634 works the same as if you had specified ``-serial tcp`` except 3635 the unix domain socket path is used for connections. 3636 3637 ``mon:dev_string`` 3638 This is a special option to allow the monitor to be multiplexed 3639 onto another serial port. The monitor is accessed with key 3640 sequence of Control-a and then pressing c. dev\_string should be 3641 any one of the serial devices specified above. An example to 3642 multiplex the monitor onto a telnet server listening on port 3643 4444 would be: 3644 3645 ``-serial mon:telnet::4444,server,nowait`` 3646 3647 When the monitor is multiplexed to stdio in this way, Ctrl+C 3648 will not terminate QEMU any more but will be passed to the guest 3649 instead. 3650 3651 ``braille`` 3652 Braille device. This will use BrlAPI to display the braille 3653 output on a real or fake device. 3654 3655 ``msmouse`` 3656 Three button serial mouse. Configure the guest to use Microsoft 3657 protocol. 3658ERST 3659 3660DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3661 "-parallel dev redirect the parallel port to char device 'dev'\n", 3662 QEMU_ARCH_ALL) 3663SRST 3664``-parallel dev`` 3665 Redirect the virtual parallel port to host device dev (same devices 3666 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3667 to use hardware devices connected on the corresponding host parallel 3668 port. 3669 3670 This option can be used several times to simulate up to 3 parallel 3671 ports. 3672 3673 Use ``-parallel none`` to disable all parallel ports. 3674ERST 3675 3676DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3677 "-monitor dev redirect the monitor to char device 'dev'\n", 3678 QEMU_ARCH_ALL) 3679SRST 3680``-monitor dev`` 3681 Redirect the monitor to host device dev (same devices as the serial 3682 port). The default device is ``vc`` in graphical mode and ``stdio`` 3683 in non graphical mode. Use ``-monitor none`` to disable the default 3684 monitor. 3685ERST 3686DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3687 "-qmp dev like -monitor but opens in 'control' mode\n", 3688 QEMU_ARCH_ALL) 3689SRST 3690``-qmp dev`` 3691 Like -monitor but opens in 'control' mode. 3692ERST 3693DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3694 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3695 QEMU_ARCH_ALL) 3696SRST 3697``-qmp-pretty dev`` 3698 Like -qmp but uses pretty JSON formatting. 3699ERST 3700 3701DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3702 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3703SRST 3704``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3705 Setup monitor on chardev name. ``pretty`` turns on JSON pretty 3706 printing easing human reading and debugging. 3707ERST 3708 3709DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3710 "-debugcon dev redirect the debug console to char device 'dev'\n", 3711 QEMU_ARCH_ALL) 3712SRST 3713``-debugcon dev`` 3714 Redirect the debug console to host device dev (same devices as the 3715 serial port). The debug console is an I/O port which is typically 3716 port 0xe9; writing to that I/O port sends output to this device. The 3717 default device is ``vc`` in graphical mode and ``stdio`` in non 3718 graphical mode. 3719ERST 3720 3721DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3722 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3723SRST 3724``-pidfile file`` 3725 Store the QEMU process PID in file. It is useful if you launch QEMU 3726 from a script. 3727ERST 3728 3729DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3730 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3731SRST 3732``-singlestep`` 3733 Run the emulation in single step mode. 3734ERST 3735 3736DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3737 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3738 QEMU_ARCH_ALL) 3739SRST 3740``--preconfig`` 3741 Pause QEMU for interactive configuration before the machine is 3742 created, which allows querying and configuring properties that will 3743 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3744 exit the preconfig state and move to the next state (i.e. run guest 3745 if -S isn't used or pause the second time if -S is used). This 3746 option is experimental. 3747ERST 3748 3749DEF("S", 0, QEMU_OPTION_S, \ 3750 "-S freeze CPU at startup (use 'c' to start execution)\n", 3751 QEMU_ARCH_ALL) 3752SRST 3753``-S`` 3754 Do not start CPU at startup (you must type 'c' in the monitor). 3755ERST 3756 3757DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3758 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3759 " run qemu with overcommit hints\n" 3760 " mem-lock=on|off controls memory lock support (default: off)\n" 3761 " cpu-pm=on|off controls cpu power management (default: off)\n", 3762 QEMU_ARCH_ALL) 3763SRST 3764``-overcommit mem-lock=on|off`` 3765 \ 3766``-overcommit cpu-pm=on|off`` 3767 Run qemu with hints about host resource overcommit. The default is 3768 to assume that host overcommits all resources. 3769 3770 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3771 (disabled by default). This works when host memory is not 3772 overcommitted and reduces the worst-case latency for guest. 3773 3774 Guest ability to manage power state of host cpus (increasing latency 3775 for other processes on the same host cpu, but decreasing latency for 3776 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3777 works best when host CPU is not overcommitted. When used, host 3778 estimates of CPU cycle and power utilization will be incorrect, not 3779 taking into account guest idle time. 3780ERST 3781 3782DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3783 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3784 " the guest without waiting for gdb to connect; use -S too\n" 3785 " if you want it to not start execution.)\n", 3786 QEMU_ARCH_ALL) 3787SRST 3788``-gdb dev`` 3789 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3790 in the System Emulation Users Guide). Note that this option does not pause QEMU 3791 execution -- if you want QEMU to not start the guest until you 3792 connect with gdb and issue a ``continue`` command, you will need to 3793 also pass the ``-S`` option to QEMU. 3794 3795 The most usual configuration is to listen on a local TCP socket:: 3796 3797 -gdb tcp::3117 3798 3799 but you can specify other backends; UDP, pseudo TTY, or even stdio 3800 are all reasonable use cases. For example, a stdio connection 3801 allows you to start QEMU from within gdb and establish the 3802 connection via a pipe: 3803 3804 .. parsed-literal:: 3805 3806 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3807ERST 3808 3809DEF("s", 0, QEMU_OPTION_s, \ 3810 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3811 QEMU_ARCH_ALL) 3812SRST 3813``-s`` 3814 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3815 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3816ERST 3817 3818DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3819 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3820 QEMU_ARCH_ALL) 3821SRST 3822``-d item1[,...]`` 3823 Enable logging of specified items. Use '-d help' for a list of log 3824 items. 3825ERST 3826 3827DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3828 "-D logfile output log to logfile (default stderr)\n", 3829 QEMU_ARCH_ALL) 3830SRST 3831``-D logfile`` 3832 Output log in logfile instead of to stderr 3833ERST 3834 3835DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3836 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3837 QEMU_ARCH_ALL) 3838SRST 3839``-dfilter range1[,...]`` 3840 Filter debug output to that relevant to a range of target addresses. 3841 The filter spec can be either start+size, start-size or start..end 3842 where start end and size are the addresses and sizes required. For 3843 example: 3844 3845 :: 3846 3847 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3848 3849 Will dump output for any code in the 0x1000 sized block starting at 3850 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3851 another 0x1000 sized block starting at 0xffffffc00005f000. 3852ERST 3853 3854DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3855 "-seed number seed the pseudo-random number generator\n", 3856 QEMU_ARCH_ALL) 3857SRST 3858``-seed number`` 3859 Force the guest to use a deterministic pseudo-random number 3860 generator, seeded with number. This does not affect crypto routines 3861 within the host. 3862ERST 3863 3864DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3865 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3866 QEMU_ARCH_ALL) 3867SRST 3868``-L path`` 3869 Set the directory for the BIOS, VGA BIOS and keymaps. 3870 3871 To list all the data directories, use ``-L help``. 3872ERST 3873 3874DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3875 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3876SRST 3877``-bios file`` 3878 Set the filename for the BIOS. 3879ERST 3880 3881DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3882 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3883SRST 3884``-enable-kvm`` 3885 Enable KVM full virtualization support. This option is only 3886 available if KVM support is enabled when compiling. 3887ERST 3888 3889DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3890 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3891DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3892 "-xen-attach attach to existing xen domain\n" 3893 " libxl will use this when starting QEMU\n", 3894 QEMU_ARCH_ALL) 3895DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3896 "-xen-domid-restrict restrict set of available xen operations\n" 3897 " to specified domain id. (Does not affect\n" 3898 " xenpv machine type).\n", 3899 QEMU_ARCH_ALL) 3900SRST 3901``-xen-domid id`` 3902 Specify xen guest domain id (XEN only). 3903 3904``-xen-attach`` 3905 Attach to existing xen domain. libxl will use this when starting 3906 QEMU (XEN only). Restrict set of available xen operations to 3907 specified domain id (XEN only). 3908ERST 3909 3910DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 3911 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 3912SRST 3913``-no-reboot`` 3914 Exit instead of rebooting. 3915ERST 3916 3917DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 3918 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 3919SRST 3920``-no-shutdown`` 3921 Don't exit QEMU on guest shutdown, but instead only stop the 3922 emulation. This allows for instance switching to monitor to commit 3923 changes to the disk image. 3924ERST 3925 3926DEF("action", HAS_ARG, QEMU_OPTION_action, 3927 "-action reboot=reset|shutdown\n" 3928 " action when guest reboots [default=reset]\n" 3929 "-action shutdown=poweroff|pause\n" 3930 " action when guest shuts down [default=poweroff]\n" 3931 "-action panic=pause|shutdown|none\n" 3932 " action when guest panics [default=shutdown]\n" 3933 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 3934 " action when watchdog fires [default=reset]\n", 3935 QEMU_ARCH_ALL) 3936SRST 3937``-action event=action`` 3938 The action parameter serves to modify QEMU's default behavior when 3939 certain guest events occur. It provides a generic method for specifying the 3940 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 3941 parameters. 3942 3943 Examples: 3944 3945 ``-action panic=none`` 3946 ``-action reboot=shutdown,shutdown=pause`` 3947 ``-watchdog i6300esb -action watchdog=pause`` 3948 3949ERST 3950 3951DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 3952 "-loadvm [tag|id]\n" \ 3953 " start right away with a saved state (loadvm in monitor)\n", 3954 QEMU_ARCH_ALL) 3955SRST 3956``-loadvm file`` 3957 Start right away with a saved state (``loadvm`` in monitor) 3958ERST 3959 3960#ifndef _WIN32 3961DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 3962 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 3963#endif 3964SRST 3965``-daemonize`` 3966 Daemonize the QEMU process after initialization. QEMU will not 3967 detach from standard IO until it is ready to receive connections on 3968 any of its devices. This option is a useful way for external 3969 programs to launch QEMU without having to cope with initialization 3970 race conditions. 3971ERST 3972 3973DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 3974 "-option-rom rom load a file, rom, into the option ROM space\n", 3975 QEMU_ARCH_ALL) 3976SRST 3977``-option-rom file`` 3978 Load the contents of file as an option ROM. This option is useful to 3979 load things like EtherBoot. 3980ERST 3981 3982DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 3983 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 3984 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 3985 QEMU_ARCH_ALL) 3986 3987SRST 3988``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 3989 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 3990 the current UTC or local time, respectively. ``localtime`` is 3991 required for correct date in MS-DOS or Windows. To start at a 3992 specific point in time, provide datetime in the format 3993 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 3994 3995 By default the RTC is driven by the host system time. This allows 3996 using of the RTC as accurate reference clock inside the guest, 3997 specifically if the host time is smoothly following an accurate 3998 external reference clock, e.g. via NTP. If you want to isolate the 3999 guest time from the host, you can set ``clock`` to ``rt`` instead, 4000 which provides a host monotonic clock if host support it. To even 4001 prevent the RTC from progressing during suspension, you can set 4002 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4003 recommended especially in icount mode in order to preserve 4004 determinism; however, note that in icount mode the speed of the 4005 virtual clock is variable and can in general differ from the host 4006 clock. 4007 4008 Enable ``driftfix`` (i386 targets only) if you experience time drift 4009 problems, specifically with Windows' ACPI HAL. This option will try 4010 to figure out how many timer interrupts were not processed by the 4011 Windows guest and will re-inject them. 4012ERST 4013 4014DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4015 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4016 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4017 " instruction, enable aligning the host and virtual clocks\n" \ 4018 " or disable real time cpu sleeping, and optionally enable\n" \ 4019 " record-and-replay mode\n", QEMU_ARCH_ALL) 4020SRST 4021``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4022 Enable virtual instruction counter. The virtual cpu will execute one 4023 instruction every 2^N ns of virtual time. If ``auto`` is specified 4024 then the virtual cpu speed will be automatically adjusted to keep 4025 virtual time within a few seconds of real time. 4026 4027 Note that while this option can give deterministic behavior, it does 4028 not provide cycle accurate emulation. Modern CPUs contain 4029 superscalar out of order cores with complex cache hierarchies. The 4030 number of instructions executed often has little or no correlation 4031 with actual performance. 4032 4033 When the virtual cpu is sleeping, the virtual time will advance at 4034 default speed unless ``sleep=on`` is specified. With 4035 ``sleep=on``, the virtual time will jump to the next timer 4036 deadline instantly whenever the virtual cpu goes to sleep mode and 4037 will not advance if no timer is enabled. This behavior gives 4038 deterministic execution times from the guest point of view. 4039 The default if icount is enabled is ``sleep=off``. 4040 ``sleep=on`` cannot be used together with either ``shift=auto`` 4041 or ``align=on``. 4042 4043 ``align=on`` will activate the delay algorithm which will try to 4044 synchronise the host clock and the virtual clock. The goal is to 4045 have a guest running at the real frequency imposed by the shift 4046 option. Whenever the guest clock is behind the host clock and if 4047 ``align=on`` is specified then we print a message to the user to 4048 inform about the delay. Currently this option does not work when 4049 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4050 shift values for which the guest clock runs ahead of the host clock. 4051 Typically this happens when the shift value is high (how high 4052 depends on the host machine). The default if icount is enabled 4053 is ``align=off``. 4054 4055 When the ``rr`` option is specified deterministic record/replay is 4056 enabled. The ``rrfile=`` option must also be provided to 4057 specify the path to the replay log. In record mode data is written 4058 to this file, and in replay mode it is read back. 4059 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4060 name. In record mode, a new VM snapshot with the given name is created 4061 at the start of execution recording. In replay mode this option 4062 specifies the snapshot name used to load the initial VM state. 4063ERST 4064 4065DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4066 "-watchdog model\n" \ 4067 " enable virtual hardware watchdog [default=none]\n", 4068 QEMU_ARCH_ALL) 4069SRST 4070``-watchdog model`` 4071 Create a virtual hardware watchdog device. Once enabled (by a guest 4072 action), the watchdog must be periodically polled by an agent inside 4073 the guest or else the guest will be restarted. Choose a model for 4074 which your guest has drivers. 4075 4076 The model is the model of hardware watchdog to emulate. Use 4077 ``-watchdog help`` to list available hardware models. Only one 4078 watchdog can be enabled for a guest. 4079 4080 The following models may be available: 4081 4082 ``ib700`` 4083 iBASE 700 is a very simple ISA watchdog with a single timer. 4084 4085 ``i6300esb`` 4086 Intel 6300ESB I/O controller hub is a much more featureful 4087 PCI-based dual-timer watchdog. 4088 4089 ``diag288`` 4090 A virtual watchdog for s390x backed by the diagnose 288 4091 hypercall (currently KVM only). 4092ERST 4093 4094DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4095 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4096 " action when watchdog fires [default=reset]\n", 4097 QEMU_ARCH_ALL) 4098SRST 4099``-watchdog-action action`` 4100 The action controls what QEMU will do when the watchdog timer 4101 expires. The default is ``reset`` (forcefully reset the guest). 4102 Other possible actions are: ``shutdown`` (attempt to gracefully 4103 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4104 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4105 guest), ``debug`` (print a debug message and continue), or ``none`` 4106 (do nothing). 4107 4108 Note that the ``shutdown`` action requires that the guest responds 4109 to ACPI signals, which it may not be able to do in the sort of 4110 situations where the watchdog would have expired, and thus 4111 ``-watchdog-action shutdown`` is not recommended for production use. 4112 4113 Examples: 4114 4115 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4116 4117ERST 4118 4119DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4120 "-echr chr set terminal escape character instead of ctrl-a\n", 4121 QEMU_ARCH_ALL) 4122SRST 4123``-echr numeric_ascii_value`` 4124 Change the escape character used for switching to the monitor when 4125 using monitor and serial sharing. The default is ``0x01`` when using 4126 the ``-nographic`` option. ``0x01`` is equal to pressing 4127 ``Control-a``. You can select a different character from the ascii 4128 control keys where 1 through 26 map to Control-a through Control-z. 4129 For instance you could use the either of the following to change the 4130 escape character to Control-t. 4131 4132 ``-echr 0x14``; \ ``-echr 20`` 4133 4134ERST 4135 4136DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4137 "-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]\n" \ 4138 "-incoming rdma:host:port[,ipv4][,ipv6]\n" \ 4139 "-incoming unix:socketpath\n" \ 4140 " prepare for incoming migration, listen on\n" \ 4141 " specified protocol and socket address\n" \ 4142 "-incoming fd:fd\n" \ 4143 "-incoming exec:cmdline\n" \ 4144 " accept incoming migration on given file descriptor\n" \ 4145 " or from given external command\n" \ 4146 "-incoming defer\n" \ 4147 " wait for the URI to be specified via migrate_incoming\n", 4148 QEMU_ARCH_ALL) 4149SRST 4150``-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]`` 4151 \ 4152``-incoming rdma:host:port[,ipv4][,ipv6]`` 4153 Prepare for incoming migration, listen on a given tcp port. 4154 4155``-incoming unix:socketpath`` 4156 Prepare for incoming migration, listen on a given unix socket. 4157 4158``-incoming fd:fd`` 4159 Accept incoming migration from a given filedescriptor. 4160 4161``-incoming exec:cmdline`` 4162 Accept incoming migration as an output from specified external 4163 command. 4164 4165``-incoming defer`` 4166 Wait for the URI to be specified via migrate\_incoming. The monitor 4167 can be used to change settings (such as migration parameters) prior 4168 to issuing the migrate\_incoming to allow the migration to begin. 4169ERST 4170 4171DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4172 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4173SRST 4174``-only-migratable`` 4175 Only allow migratable devices. Devices will not be allowed to enter 4176 an unmigratable state. 4177ERST 4178 4179DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4180 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4181SRST 4182``-nodefaults`` 4183 Don't create default devices. Normally, QEMU sets the default 4184 devices like serial port, parallel port, virtual console, monitor 4185 device, VGA adapter, floppy and CD-ROM drive and others. The 4186 ``-nodefaults`` option will disable all those default devices. 4187ERST 4188 4189#ifndef _WIN32 4190DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4191 "-chroot dir chroot to dir just before starting the VM\n", 4192 QEMU_ARCH_ALL) 4193#endif 4194SRST 4195``-chroot dir`` 4196 Immediately before starting guest execution, chroot to the specified 4197 directory. Especially useful in combination with -runas. 4198ERST 4199 4200#ifndef _WIN32 4201DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4202 "-runas user change to user id user just before starting the VM\n" \ 4203 " user can be numeric uid:gid instead\n", 4204 QEMU_ARCH_ALL) 4205#endif 4206SRST 4207``-runas user`` 4208 Immediately before starting guest execution, drop root privileges, 4209 switching to the specified user. 4210ERST 4211 4212DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4213 "-prom-env variable=value\n" 4214 " set OpenBIOS nvram variables\n", 4215 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4216SRST 4217``-prom-env variable=value`` 4218 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4219 4220 :: 4221 4222 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4223 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4224 4225 :: 4226 4227 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4228 -prom-env 'boot-device=hd:2,\yaboot' \ 4229 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4230ERST 4231DEF("semihosting", 0, QEMU_OPTION_semihosting, 4232 "-semihosting semihosting mode\n", 4233 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4234 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4235SRST 4236``-semihosting`` 4237 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4238 4239 Note that this allows guest direct access to the host filesystem, so 4240 should only be used with a trusted guest OS. 4241 4242 See the -semihosting-config option documentation for further 4243 information about the facilities this enables. 4244ERST 4245DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4246 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4247 " semihosting configuration\n", 4248QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 | 4249QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4250SRST 4251``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4252 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4253 only). 4254 4255 Note that this allows guest direct access to the host filesystem, so 4256 should only be used with a trusted guest OS. 4257 4258 On Arm this implements the standard semihosting API, version 2.0. 4259 4260 On M68K this implements the "ColdFire GDB" interface used by 4261 libgloss. 4262 4263 Xtensa semihosting provides basic file IO calls, such as 4264 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4265 linux platform "sim" use this interface. 4266 4267 On RISC-V this implements the standard semihosting API, version 0.2. 4268 4269 ``target=native|gdb|auto`` 4270 Defines where the semihosting calls will be addressed, to QEMU 4271 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4272 means ``gdb`` during debug sessions and ``native`` otherwise. 4273 4274 ``chardev=str1`` 4275 Send the output to a chardev backend output for native or auto 4276 output when not in gdb 4277 4278 ``arg=str1,arg=str2,...`` 4279 Allows the user to pass input arguments, and can be used 4280 multiple times to build up a list. The old-style 4281 ``-kernel``/``-append`` method of passing a command line is 4282 still supported for backward compatibility. If both the 4283 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4284 specified, the former is passed to semihosting as it always 4285 takes precedence. 4286ERST 4287DEF("old-param", 0, QEMU_OPTION_old_param, 4288 "-old-param old param mode\n", QEMU_ARCH_ARM) 4289SRST 4290``-old-param`` 4291 Old param mode (ARM only). 4292ERST 4293 4294DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4295 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4296 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4297 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4298 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4299 " by the kernel, but typically no longer used by modern\n" \ 4300 " C library implementations.\n" \ 4301 " use 'elevateprivileges' to allow or deny QEMU process to elevate\n" \ 4302 " its privileges by blacklisting all set*uid|gid system calls.\n" \ 4303 " The value 'children' will deny set*uid|gid system calls for\n" \ 4304 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4305 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4306 " blacklisting *fork and execve\n" \ 4307 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4308 QEMU_ARCH_ALL) 4309SRST 4310``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4311 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4312 filtering and 'off' will disable it. The default is 'off'. 4313 4314 ``obsolete=string`` 4315 Enable Obsolete system calls 4316 4317 ``elevateprivileges=string`` 4318 Disable set\*uid\|gid system calls 4319 4320 ``spawn=string`` 4321 Disable \*fork and execve 4322 4323 ``resourcecontrol=string`` 4324 Disable process affinity and schedular priority 4325ERST 4326 4327DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4328 "-readconfig <file>\n", QEMU_ARCH_ALL) 4329SRST 4330``-readconfig file`` 4331 Read device configuration from file. This approach is useful when 4332 you want to spawn QEMU process with many command line options but 4333 you don't want to exceed the command line character limit. 4334ERST 4335DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4336 "-writeconfig <file>\n" 4337 " read/write config file\n", QEMU_ARCH_ALL) 4338SRST 4339``-writeconfig file`` 4340 Write device configuration to file. The file can be either filename 4341 to save command line and device configuration into file or dash 4342 ``-``) character to print the output to stdout. This can be later 4343 used as input file for ``-readconfig`` option. 4344ERST 4345 4346DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4347 "-no-user-config\n" 4348 " do not load default user-provided config files at startup\n", 4349 QEMU_ARCH_ALL) 4350SRST 4351``-no-user-config`` 4352 The ``-no-user-config`` option makes QEMU not load any of the 4353 user-provided config files on sysconfdir. 4354ERST 4355 4356DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4357 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4358 " specify tracing options\n", 4359 QEMU_ARCH_ALL) 4360SRST 4361``-trace [[enable=]pattern][,events=file][,file=file]`` 4362 .. include:: ../qemu-option-trace.rst.inc 4363 4364ERST 4365DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4366 "-plugin [file=]<file>[,arg=<string>]\n" 4367 " load a plugin\n", 4368 QEMU_ARCH_ALL) 4369SRST 4370``-plugin file=file[,arg=string]`` 4371 Load a plugin. 4372 4373 ``file=file`` 4374 Load the given plugin from a shared library file. 4375 4376 ``arg=string`` 4377 Argument string passed to the plugin. (Can be given multiple 4378 times.) 4379ERST 4380 4381HXCOMM Internal use 4382DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4383DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4384 4385#ifdef __linux__ 4386DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4387 "-enable-fips enable FIPS 140-2 compliance\n", 4388 QEMU_ARCH_ALL) 4389#endif 4390SRST 4391``-enable-fips`` 4392 Enable FIPS 140-2 compliance mode. 4393ERST 4394 4395DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4396 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4397 " control error message format\n" 4398 " timestamp=on enables timestamps (default: off)\n" 4399 " guest-name=on enables guest name prefix but only if\n" 4400 " -name guest option is set (default: off)\n", 4401 QEMU_ARCH_ALL) 4402SRST 4403``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4404 Control error message format. 4405 4406 ``timestamp=on|off`` 4407 Prefix messages with a timestamp. Default is off. 4408 4409 ``guest-name=on|off`` 4410 Prefix messages with guest name but only if -name guest option is set 4411 otherwise the option is ignored. Default is off. 4412ERST 4413 4414DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4415 "-dump-vmstate <file>\n" 4416 " Output vmstate information in JSON format to file.\n" 4417 " Use the scripts/vmstate-static-checker.py file to\n" 4418 " check for possible regressions in migration code\n" 4419 " by comparing two such vmstate dumps.\n", 4420 QEMU_ARCH_ALL) 4421SRST 4422``-dump-vmstate file`` 4423 Dump json-encoded vmstate information for current machine type to 4424 file in file 4425ERST 4426 4427DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4428 "-enable-sync-profile\n" 4429 " enable synchronization profiling\n", 4430 QEMU_ARCH_ALL) 4431SRST 4432``-enable-sync-profile`` 4433 Enable synchronization profiling. 4434ERST 4435 4436DEFHEADING() 4437 4438DEFHEADING(Generic object creation:) 4439 4440DEF("object", HAS_ARG, QEMU_OPTION_object, 4441 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4442 " create a new object of type TYPENAME setting properties\n" 4443 " in the order they are specified. Note that the 'id'\n" 4444 " property must be set. These objects are placed in the\n" 4445 " '/objects' path.\n", 4446 QEMU_ARCH_ALL) 4447SRST 4448``-object typename[,prop1=value1,...]`` 4449 Create a new object of type typename setting properties in the order 4450 they are specified. Note that the 'id' property must be set. These 4451 objects are placed in the '/objects' path. 4452 4453 ``-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`` 4454 Creates a memory file backend object, which can be used to back 4455 the guest RAM with huge pages. 4456 4457 The ``id`` parameter is a unique ID that will be used to 4458 reference this memory region when configuring the ``-numa`` 4459 argument. 4460 4461 The ``size`` option provides the size of the memory region, and 4462 accepts common suffixes, eg ``500M``. 4463 4464 The ``mem-path`` provides the path to either a shared memory or 4465 huge page filesystem mount. 4466 4467 The ``share`` boolean option determines whether the memory 4468 region is marked as private to QEMU, or shared. The latter 4469 allows a co-operating external process to access the QEMU memory 4470 region. 4471 4472 The ``share`` is also required for pvrdma devices due to 4473 limitations in the RDMA API provided by Linux. 4474 4475 Setting share=on might affect the ability to configure NUMA 4476 bindings for the memory backend under some circumstances, see 4477 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4478 source tree for additional details. 4479 4480 Setting the ``discard-data`` boolean option to on indicates that 4481 file contents can be destroyed when QEMU exits, to avoid 4482 unnecessarily flushing data to the backing file. Note that 4483 ``discard-data`` is only an optimization, and QEMU might not 4484 discard file contents if it aborts unexpectedly or is terminated 4485 using SIGKILL. 4486 4487 The ``merge`` boolean option enables memory merge, also known as 4488 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4489 the pages for memory deduplication. 4490 4491 Setting the ``dump`` boolean option to off excludes the memory 4492 from core dumps. This feature is also known as MADV\_DONTDUMP. 4493 4494 The ``prealloc`` boolean option enables memory preallocation. 4495 4496 The ``host-nodes`` option binds the memory range to a list of 4497 NUMA host nodes. 4498 4499 The ``policy`` option sets the NUMA policy to one of the 4500 following values: 4501 4502 ``default`` 4503 default host policy 4504 4505 ``preferred`` 4506 prefer the given host node list for allocation 4507 4508 ``bind`` 4509 restrict memory allocation to the given host node list 4510 4511 ``interleave`` 4512 interleave memory allocations across the given host node 4513 list 4514 4515 The ``align`` option specifies the base address alignment when 4516 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4517 ``2M``. Some backend store specified by ``mem-path`` requires an 4518 alignment different than the default one used by QEMU, eg the 4519 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4520 such cases, users can specify the required alignment via this 4521 option. 4522 4523 The ``pmem`` option specifies whether the backing file specified 4524 by ``mem-path`` is in host persistent memory that can be 4525 accessed using the SNIA NVM programming model (e.g. Intel 4526 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4527 operations to guarantee the persistence of its own writes to 4528 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4529 migration). Also, we will map the backend-file with MAP\_SYNC 4530 flag, which ensures the file metadata is in sync for 4531 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4532 requires support from both the host kernel (since Linux kernel 4533 4.15) and the filesystem of ``mem-path`` mounted with DAX 4534 option. 4535 4536 The ``readonly`` option specifies whether the backing file is opened 4537 read-only or read-write (default). 4538 4539 ``-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`` 4540 Creates a memory backend object, which can be used to back the 4541 guest RAM. Memory backend objects offer more control than the 4542 ``-m`` option that is traditionally used to define guest RAM. 4543 Please refer to ``memory-backend-file`` for a description of the 4544 options. 4545 4546 ``-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`` 4547 Creates an anonymous memory file backend object, which allows 4548 QEMU to share the memory with an external process (e.g. when 4549 using vhost-user). The memory is allocated with memfd and 4550 optional sealing. (Linux only) 4551 4552 The ``seal`` option creates a sealed-file, that will block 4553 further resizing the memory ('on' by default). 4554 4555 The ``hugetlb`` option specify the file to be created resides in 4556 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4557 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4558 the hugetlb page size on systems that support multiple hugetlb 4559 page sizes (it must be a power of 2 value supported by the 4560 system). 4561 4562 In some versions of Linux, the ``hugetlb`` option is 4563 incompatible with the ``seal`` option (requires at least Linux 4564 4.16). 4565 4566 Please refer to ``memory-backend-file`` for a description of the 4567 other options. 4568 4569 The ``share`` boolean option is on by default with memfd. 4570 4571 ``-object rng-builtin,id=id`` 4572 Creates a random number generator backend which obtains entropy 4573 from QEMU builtin functions. The ``id`` parameter is a unique ID 4574 that will be used to reference this entropy backend from the 4575 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4576 uses this RNG backend. 4577 4578 ``-object rng-random,id=id,filename=/dev/random`` 4579 Creates a random number generator backend which obtains entropy 4580 from a device on the host. The ``id`` parameter is a unique ID 4581 that will be used to reference this entropy backend from the 4582 ``virtio-rng`` device. The ``filename`` parameter specifies 4583 which file to obtain entropy from and if omitted defaults to 4584 ``/dev/urandom``. 4585 4586 ``-object rng-egd,id=id,chardev=chardevid`` 4587 Creates a random number generator backend which obtains entropy 4588 from an external daemon running on the host. The ``id`` 4589 parameter is a unique ID that will be used to reference this 4590 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4591 parameter is the unique ID of a character device backend that 4592 provides the connection to the RNG daemon. 4593 4594 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4595 Creates a TLS anonymous credentials object, which can be used to 4596 provide TLS support on network backends. The ``id`` parameter is 4597 a unique ID which network backends will use to access the 4598 credentials. The ``endpoint`` is either ``server`` or ``client`` 4599 depending on whether the QEMU network backend that uses the 4600 credentials will be acting as a client or as a server. If 4601 ``verify-peer`` is enabled (the default) then once the handshake 4602 is completed, the peer credentials will be verified, though this 4603 is a no-op for anonymous credentials. 4604 4605 The dir parameter tells QEMU where to find the credential files. 4606 For server endpoints, this directory may contain a file 4607 dh-params.pem providing diffie-hellman parameters to use for the 4608 TLS server. If the file is missing, QEMU will generate a set of 4609 DH parameters at startup. This is a computationally expensive 4610 operation that consumes random pool entropy, so it is 4611 recommended that a persistent set of parameters be generated 4612 upfront and saved. 4613 4614 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4615 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4616 can be used to provide TLS support on network backends. The 4617 ``id`` parameter is a unique ID which network backends will use 4618 to access the credentials. The ``endpoint`` is either ``server`` 4619 or ``client`` depending on whether the QEMU network backend that 4620 uses the credentials will be acting as a client or as a server. 4621 For clients only, ``username`` is the username which will be 4622 sent to the server. If omitted it defaults to "qemu". 4623 4624 The dir parameter tells QEMU where to find the keys file. It is 4625 called "dir/keys.psk" and contains "username:key" pairs. This 4626 file can most easily be created using the GnuTLS ``psktool`` 4627 program. 4628 4629 For server endpoints, dir may also contain a file dh-params.pem 4630 providing diffie-hellman parameters to use for the TLS server. 4631 If the file is missing, QEMU will generate a set of DH 4632 parameters at startup. This is a computationally expensive 4633 operation that consumes random pool entropy, so it is 4634 recommended that a persistent set of parameters be generated up 4635 front and saved. 4636 4637 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4638 Creates a TLS anonymous credentials object, which can be used to 4639 provide TLS support on network backends. The ``id`` parameter is 4640 a unique ID which network backends will use to access the 4641 credentials. The ``endpoint`` is either ``server`` or ``client`` 4642 depending on whether the QEMU network backend that uses the 4643 credentials will be acting as a client or as a server. If 4644 ``verify-peer`` is enabled (the default) then once the handshake 4645 is completed, the peer credentials will be verified. With x509 4646 certificates, this implies that the clients must be provided 4647 with valid client certificates too. 4648 4649 The dir parameter tells QEMU where to find the credential files. 4650 For server endpoints, this directory may contain a file 4651 dh-params.pem providing diffie-hellman parameters to use for the 4652 TLS server. If the file is missing, QEMU will generate a set of 4653 DH parameters at startup. This is a computationally expensive 4654 operation that consumes random pool entropy, so it is 4655 recommended that a persistent set of parameters be generated 4656 upfront and saved. 4657 4658 For x509 certificate credentials the directory will contain 4659 further files providing the x509 certificates. The certificates 4660 must be stored in PEM format, in filenames ca-cert.pem, 4661 ca-crl.pem (optional), server-cert.pem (only servers), 4662 server-key.pem (only servers), client-cert.pem (only clients), 4663 and client-key.pem (only clients). 4664 4665 For the server-key.pem and client-key.pem files which contain 4666 sensitive private keys, it is possible to use an encrypted 4667 version by providing the passwordid parameter. This provides the 4668 ID of a previously created ``secret`` object containing the 4669 password for decryption. 4670 4671 The priority parameter allows to override the global default 4672 priority used by gnutls. This can be useful if the system 4673 administrator needs to use a weaker set of crypto priorities for 4674 QEMU without potentially forcing the weakness onto all 4675 applications. Or conversely if one wants wants a stronger 4676 default for QEMU than for all other applications, they can do 4677 this through this parameter. Its format is a gnutls priority 4678 string as described at 4679 https://gnutls.org/manual/html_node/Priority-Strings.html. 4680 4681 ``-object tls-cipher-suites,id=id,priority=priority`` 4682 Creates a TLS cipher suites object, which can be used to control 4683 the TLS cipher/protocol algorithms that applications are permitted 4684 to use. 4685 4686 The ``id`` parameter is a unique ID which frontends will use to 4687 access the ordered list of permitted TLS cipher suites from the 4688 host. 4689 4690 The ``priority`` parameter allows to override the global default 4691 priority used by gnutls. This can be useful if the system 4692 administrator needs to use a weaker set of crypto priorities for 4693 QEMU without potentially forcing the weakness onto all 4694 applications. Or conversely if one wants wants a stronger 4695 default for QEMU than for all other applications, they can do 4696 this through this parameter. Its format is a gnutls priority 4697 string as described at 4698 https://gnutls.org/manual/html_node/Priority-Strings.html. 4699 4700 An example of use of this object is to control UEFI HTTPS Boot. 4701 The tls-cipher-suites object exposes the ordered list of permitted 4702 TLS cipher suites from the host side to the guest firmware, via 4703 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4704 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4705 guest-side TLS. 4706 4707 In the following example, the priority at which the host-side policy 4708 is retrieved is given by the ``priority`` property. 4709 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4710 refer to /etc/crypto-policies/back-ends/gnutls.config. 4711 4712 .. parsed-literal:: 4713 4714 # |qemu_system| \\ 4715 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4716 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4717 4718 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4719 Interval t can't be 0, this filter batches the packet delivery: 4720 all packets arriving in a given interval on netdev netdevid are 4721 delayed until the end of the interval. Interval is in 4722 microseconds. ``status`` is optional that indicate whether the 4723 netfilter is on (enabled) or off (disabled), the default status 4724 for netfilter will be 'on'. 4725 4726 queue all\|rx\|tx is an option that can be applied to any 4727 netfilter. 4728 4729 ``all``: the filter is attached both to the receive and the 4730 transmit queue of the netdev (default). 4731 4732 ``rx``: the filter is attached to the receive queue of the 4733 netdev, where it will receive packets sent to the netdev. 4734 4735 ``tx``: the filter is attached to the transmit queue of the 4736 netdev, where it will receive packets sent by the netdev. 4737 4738 position head\|tail\|id=<id> is an option to specify where the 4739 filter should be inserted in the filter list. It can be applied 4740 to any netfilter. 4741 4742 ``head``: the filter is inserted at the head of the filter list, 4743 before any existing filters. 4744 4745 ``tail``: the filter is inserted at the tail of the filter list, 4746 behind any existing filters (default). 4747 4748 ``id=<id>``: the filter is inserted before or behind the filter 4749 specified by <id>, see the insert option below. 4750 4751 insert behind\|before is an option to specify where to insert 4752 the new filter relative to the one specified with 4753 position=id=<id>. It can be applied to any netfilter. 4754 4755 ``before``: insert before the specified filter. 4756 4757 ``behind``: insert behind the specified filter (default). 4758 4759 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4760 filter-mirror on netdev netdevid,mirror net packet to 4761 chardevchardevid, if it has the vnet\_hdr\_support flag, 4762 filter-mirror will mirror packet with vnet\_hdr\_len. 4763 4764 ``-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]`` 4765 filter-redirector on netdev netdevid,redirect filter's net 4766 packet to chardev chardevid,and redirect indev's packet to 4767 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4768 will redirect packet with vnet\_hdr\_len. Create a 4769 filter-redirector we need to differ outdev id from indev id, id 4770 can not be the same. we can just use indev or outdev, but at 4771 least one of indev or outdev need to be specified. 4772 4773 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4774 Filter-rewriter is a part of COLO project.It will rewrite tcp 4775 packet to secondary from primary to keep secondary tcp 4776 connection,and rewrite tcp packet to primary from secondary make 4777 tcp packet can be handled by client.if it has the 4778 vnet\_hdr\_support flag, we can parse packet with vnet header. 4779 4780 usage: colo secondary: -object 4781 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4782 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4783 filter-rewriter,id=rew0,netdev=hn0,queue=all 4784 4785 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4786 Dump the network traffic on netdev dev to the file specified by 4787 filename. At most len bytes (64k by default) per packet are 4788 stored. The file format is libpcap, so it can be analyzed with 4789 tools such as tcpdump or Wireshark. 4790 4791 ``-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}]`` 4792 Colo-compare gets packet from primary\_in chardevid and 4793 secondary\_in, then compare whether the payload of primary packet 4794 and secondary packet are the same. If same, it will output 4795 primary packet to out\_dev, else it will notify COLO-framework to do 4796 checkpoint and send primary packet to out\_dev. In order to 4797 improve efficiency, we need to put the task of comparison in 4798 another iothread. If it has the vnet\_hdr\_support flag, 4799 colo compare will send/recv packet with vnet\_hdr\_len. 4800 The compare\_timeout=@var{ms} determines the maximum time of the 4801 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4802 is to set the period of scanning expired primary node network packets. 4803 The max\_queue\_size=@var{size} is to set the max compare queue 4804 size depend on user environment. 4805 If user want to use Xen COLO, need to add the notify\_dev to 4806 notify Xen colo-frame to do checkpoint. 4807 4808 COLO-compare must be used with the help of filter-mirror, 4809 filter-redirector and filter-rewriter. 4810 4811 :: 4812 4813 KVM COLO 4814 4815 primary: 4816 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4817 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4818 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4819 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4820 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4821 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4822 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4823 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4824 -object iothread,id=iothread1 4825 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4826 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4827 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4828 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4829 4830 secondary: 4831 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4832 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4833 -chardev socket,id=red0,host=3.3.3.3,port=9003 4834 -chardev socket,id=red1,host=3.3.3.3,port=9004 4835 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4836 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4837 4838 4839 Xen COLO 4840 4841 primary: 4842 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4843 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4844 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait 4845 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait 4846 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait 4847 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4848 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait 4849 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4850 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server,nowait 4851 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4852 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4853 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4854 -object iothread,id=iothread1 4855 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4856 4857 secondary: 4858 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4859 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4860 -chardev socket,id=red0,host=3.3.3.3,port=9003 4861 -chardev socket,id=red1,host=3.3.3.3,port=9004 4862 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4863 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4864 4865 If you want to know the detail of above command line, you can 4866 read the colo-compare git log. 4867 4868 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4869 Creates a cryptodev backend which executes crypto opreation from 4870 the QEMU cipher APIS. The id parameter is a unique ID that will 4871 be used to reference this cryptodev backend from the 4872 ``virtio-crypto`` device. The queues parameter is optional, 4873 which specify the queue number of cryptodev backend, the default 4874 of queues is 1. 4875 4876 .. parsed-literal:: 4877 4878 # |qemu_system| \\ 4879 [...] \\ 4880 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4881 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4882 [...] 4883 4884 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4885 Creates a vhost-user cryptodev backend, backed by a chardev 4886 chardevid. The id parameter is a unique ID that will be used to 4887 reference this cryptodev backend from the ``virtio-crypto`` 4888 device. The chardev should be a unix domain socket backed one. 4889 The vhost-user uses a specifically defined protocol to pass 4890 vhost ioctl replacement messages to an application on the other 4891 end of the socket. The queues parameter is optional, which 4892 specify the queue number of cryptodev backend for multiqueue 4893 vhost-user, the default of queues is 1. 4894 4895 .. parsed-literal:: 4896 4897 # |qemu_system| \\ 4898 [...] \\ 4899 -chardev socket,id=chardev0,path=/path/to/socket \\ 4900 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4901 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4902 [...] 4903 4904 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 4905 \ 4906 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 4907 Defines a secret to store a password, encryption key, or some 4908 other sensitive data. The sensitive data can either be passed 4909 directly via the data parameter, or indirectly via the file 4910 parameter. Using the data parameter is insecure unless the 4911 sensitive data is encrypted. 4912 4913 The sensitive data can be provided in raw format (the default), 4914 or base64. When encoded as JSON, the raw format only supports 4915 valid UTF-8 characters, so base64 is recommended for sending 4916 binary data. QEMU will convert from which ever format is 4917 provided to the format it needs internally. eg, an RBD password 4918 can be provided in raw format, even though it will be base64 4919 encoded when passed onto the RBD sever. 4920 4921 For added protection, it is possible to encrypt the data 4922 associated with a secret using the AES-256-CBC cipher. Use of 4923 encryption is indicated by providing the keyid and iv 4924 parameters. The keyid parameter provides the ID of a previously 4925 defined secret that contains the AES-256 decryption key. This 4926 key should be 32-bytes long and be base64 encoded. The iv 4927 parameter provides the random initialization vector used for 4928 encryption of this particular secret and should be a base64 4929 encrypted string of the 16-byte IV. 4930 4931 The simplest (insecure) usage is to provide the secret inline 4932 4933 .. parsed-literal:: 4934 4935 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 4936 4937 The simplest secure usage is to provide the secret via a file 4938 4939 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 4940 secret,id=sec0,file=mypasswd.txt,format=raw 4941 4942 For greater security, AES-256-CBC should be used. To illustrate 4943 usage, consider the openssl command line tool which can encrypt 4944 the data. Note that when encrypting, the plaintext must be 4945 padded to the cipher block size (32 bytes) using the standard 4946 PKCS#5/6 compatible padding algorithm. 4947 4948 First a master key needs to be created in base64 encoding: 4949 4950 :: 4951 4952 # openssl rand -base64 32 > key.b64 4953 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 4954 4955 Each secret to be encrypted needs to have a random 4956 initialization vector generated. These do not need to be kept 4957 secret 4958 4959 :: 4960 4961 # openssl rand -base64 16 > iv.b64 4962 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 4963 4964 The secret to be defined can now be encrypted, in this case 4965 we're telling openssl to base64 encode the result, but it could 4966 be left as raw bytes if desired. 4967 4968 :: 4969 4970 # SECRET=$(printf "letmein" | 4971 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 4972 4973 When launching QEMU, create a master secret pointing to 4974 ``key.b64`` and specify that to be used to decrypt the user 4975 password. Pass the contents of ``iv.b64`` to the second secret 4976 4977 .. parsed-literal:: 4978 4979 # |qemu_system| \\ 4980 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 4981 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 4982 data=$SECRET,iv=$(<iv.b64) 4983 4984 ``-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]`` 4985 Create a Secure Encrypted Virtualization (SEV) guest object, 4986 which can be used to provide the guest memory encryption support 4987 on AMD processors. 4988 4989 When memory encryption is enabled, one of the physical address 4990 bit (aka the C-bit) is utilized to mark if a memory page is 4991 protected. The ``cbitpos`` is used to provide the C-bit 4992 position. The C-bit position is Host family dependent hence user 4993 must provide this value. On EPYC, the value should be 47. 4994 4995 When memory encryption is enabled, we loose certain bits in 4996 physical address space. The ``reduced-phys-bits`` is used to 4997 provide the number of bits we loose in physical address space. 4998 Similar to C-bit, the value is Host family dependent. On EPYC, 4999 the value should be 5. 5000 5001 The ``sev-device`` provides the device file to use for 5002 communicating with the SEV firmware running inside AMD Secure 5003 Processor. The default device is '/dev/sev'. If hardware 5004 supports memory encryption then /dev/sev devices are created by 5005 CCP driver. 5006 5007 The ``policy`` provides the guest policy to be enforced by the 5008 SEV firmware and restrict what configuration and operational 5009 commands can be performed on this guest by the hypervisor. The 5010 policy should be provided by the guest owner and is bound to the 5011 guest and cannot be changed throughout the lifetime of the 5012 guest. The default is 0. 5013 5014 If guest ``policy`` allows sharing the key with another SEV 5015 guest then ``handle`` can be use to provide handle of the guest 5016 from which to share the key. 5017 5018 The ``dh-cert-file`` and ``session-file`` provides the guest 5019 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5020 and session parameters are used for establishing a cryptographic 5021 session with the guest owner to negotiate keys used for 5022 attestation. The file must be encoded in base64. 5023 5024 e.g to launch a SEV guest 5025 5026 .. parsed-literal:: 5027 5028 # |qemu_system_x86| \\ 5029 ...... \\ 5030 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5031 -machine ...,memory-encryption=sev0 \\ 5032 ..... 5033 5034 ``-object authz-simple,id=id,identity=string`` 5035 Create an authorization object that will control access to 5036 network services. 5037 5038 The ``identity`` parameter is identifies the user and its format 5039 depends on the network service that authorization object is 5040 associated with. For authorizing based on TLS x509 certificates, 5041 the identity must be the x509 distinguished name. Note that care 5042 must be taken to escape any commas in the distinguished name. 5043 5044 An example authorization object to validate a x509 distinguished 5045 name would look like: 5046 5047 .. parsed-literal:: 5048 5049 # |qemu_system| \\ 5050 ... \\ 5051 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5052 ... 5053 5054 Note the use of quotes due to the x509 distinguished name 5055 containing whitespace, and escaping of ','. 5056 5057 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5058 Create an authorization object that will control access to 5059 network services. 5060 5061 The ``filename`` parameter is the fully qualified path to a file 5062 containing the access control list rules in JSON format. 5063 5064 An example set of rules that match against SASL usernames might 5065 look like: 5066 5067 :: 5068 5069 { 5070 "rules": [ 5071 { "match": "fred", "policy": "allow", "format": "exact" }, 5072 { "match": "bob", "policy": "allow", "format": "exact" }, 5073 { "match": "danb", "policy": "deny", "format": "glob" }, 5074 { "match": "dan*", "policy": "allow", "format": "exact" }, 5075 ], 5076 "policy": "deny" 5077 } 5078 5079 When checking access the object will iterate over all the rules 5080 and the first rule to match will have its ``policy`` value 5081 returned as the result. If no rules match, then the default 5082 ``policy`` value is returned. 5083 5084 The rules can either be an exact string match, or they can use 5085 the simple UNIX glob pattern matching to allow wildcards to be 5086 used. 5087 5088 If ``refresh`` is set to true the file will be monitored and 5089 automatically reloaded whenever its content changes. 5090 5091 As with the ``authz-simple`` object, the format of the identity 5092 strings being matched depends on the network service, but is 5093 usually a TLS x509 distinguished name, or a SASL username. 5094 5095 An example authorization object to validate a SASL username 5096 would look like: 5097 5098 .. parsed-literal:: 5099 5100 # |qemu_system| \\ 5101 ... \\ 5102 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5103 ... 5104 5105 ``-object authz-pam,id=id,service=string`` 5106 Create an authorization object that will control access to 5107 network services. 5108 5109 The ``service`` parameter provides the name of a PAM service to 5110 use for authorization. It requires that a file 5111 ``/etc/pam.d/service`` exist to provide the configuration for 5112 the ``account`` subsystem. 5113 5114 An example authorization object to validate a TLS x509 5115 distinguished name would look like: 5116 5117 .. parsed-literal:: 5118 5119 # |qemu_system| \\ 5120 ... \\ 5121 -object authz-pam,id=auth0,service=qemu-vnc \\ 5122 ... 5123 5124 There would then be a corresponding config file for PAM at 5125 ``/etc/pam.d/qemu-vnc`` that contains: 5126 5127 :: 5128 5129 account requisite pam_listfile.so item=user sense=allow \ 5130 file=/etc/qemu/vnc.allow 5131 5132 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5133 of x509 distingished names that are permitted access 5134 5135 :: 5136 5137 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5138 5139 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5140 Creates a dedicated event loop thread that devices can be 5141 assigned to. This is known as an IOThread. By default device 5142 emulation happens in vCPU threads or the main event loop thread. 5143 This can become a scalability bottleneck. IOThreads allow device 5144 emulation and I/O to run on other host CPUs. 5145 5146 The ``id`` parameter is a unique ID that will be used to 5147 reference this IOThread from ``-device ...,iothread=id``. 5148 Multiple devices can be assigned to an IOThread. Note that not 5149 all devices support an ``iothread`` parameter. 5150 5151 The ``query-iothreads`` QMP command lists IOThreads and reports 5152 their thread IDs so that the user can configure host CPU 5153 pinning/affinity. 5154 5155 IOThreads use an adaptive polling algorithm to reduce event loop 5156 latency. Instead of entering a blocking system call to monitor 5157 file descriptors and then pay the cost of being woken up when an 5158 event occurs, the polling algorithm spins waiting for events for 5159 a short time. The algorithm's default parameters are suitable 5160 for many cases but can be adjusted based on knowledge of the 5161 workload and/or host device latency. 5162 5163 The ``poll-max-ns`` parameter is the maximum number of 5164 nanoseconds to busy wait for events. Polling can be disabled by 5165 setting this value to 0. 5166 5167 The ``poll-grow`` parameter is the multiplier used to increase 5168 the polling time when the algorithm detects it is missing events 5169 due to not polling long enough. 5170 5171 The ``poll-shrink`` parameter is the divisor used to decrease 5172 the polling time when the algorithm detects it is spending too 5173 long polling without encountering events. 5174 5175 The polling parameters can be modified at run-time using the 5176 ``qom-set`` command (where ``iothread1`` is the IOThread's 5177 ``id``): 5178 5179 :: 5180 5181 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5182ERST 5183 5184 5185HXCOMM This is the last statement. Insert new options before this line! 5186
