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, nvmm, 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, nvmm, 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, nvmm, 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 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 145 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 146SRST 147``-accel name[,prop=value[,...]]`` 148 This is used to enable an accelerator. Depending on the target 149 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 150 default, tcg is used. If there is more than one accelerator 151 specified, the next one is used if the previous one fails to 152 initialize. 153 154 ``igd-passthru=on|off`` 155 When Xen is in use, this option controls whether Intel 156 integrated graphics devices can be passed through to the guest 157 (default=off) 158 159 ``kernel-irqchip=on|off|split`` 160 Controls KVM in-kernel irqchip support. The default is full 161 acceleration of the interrupt controllers. On x86, split irqchip 162 reduces the kernel attack surface, at a performance cost for 163 non-MSI interrupts. Disabling the in-kernel irqchip completely 164 is not recommended except for debugging purposes. 165 166 ``kvm-shadow-mem=size`` 167 Defines the size of the KVM shadow MMU. 168 169 ``split-wx=on|off`` 170 Controls the use of split w^x mapping for the TCG code generation 171 buffer. Some operating systems require this to be enabled, and in 172 such a case this will default on. On other operating systems, this 173 will default off, but one may enable this for testing or debugging. 174 175 ``tb-size=n`` 176 Controls the size (in MiB) of the TCG translation block cache. 177 178 ``thread=single|multi`` 179 Controls number of TCG threads. When the TCG is multi-threaded 180 there will be one thread per vCPU therefore taking advantage of 181 additional host cores. The default is to enable multi-threading 182 where both the back-end and front-ends support it and no 183 incompatible TCG features have been enabled (e.g. 184 icount/replay). 185 186 ``dirty-ring-size=n`` 187 When the KVM accelerator is used, it controls the size of the per-vCPU 188 dirty page ring buffer (number of entries for each vCPU). It should 189 be a value that is power of two, and it should be 1024 or bigger (but 190 still less than the maximum value that the kernel supports). 4096 191 could be a good initial value if you have no idea which is the best. 192 Set this value to 0 to disable the feature. By default, this feature 193 is disabled (dirty-ring-size=0). When enabled, KVM will instead 194 record dirty pages in a bitmap. 195 196ERST 197 198DEF("smp", HAS_ARG, QEMU_OPTION_smp, 199 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 200 " set the number of CPUs to 'n' [default=1]\n" 201 " maxcpus= maximum number of total cpus, including\n" 202 " offline CPUs for hotplug, etc\n" 203 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 204 " threads= number of threads on one CPU core\n" 205 " dies= number of CPU dies on one socket (for PC only)\n" 206 " sockets= number of discrete sockets in the system\n", 207 QEMU_ARCH_ALL) 208SRST 209``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 210 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 211 are supported. On Sparc32 target, Linux limits the number of usable 212 CPUs to 4. For the PC target, the number of cores per die, the 213 number of threads per cores, the number of dies per packages and the 214 total number of sockets can be specified. Missing values will be 215 computed. If any on the three values is given, the total number of 216 CPUs n can be omitted. maxcpus specifies the maximum number of 217 hotpluggable CPUs. 218ERST 219 220DEF("numa", HAS_ARG, QEMU_OPTION_numa, 221 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 222 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 223 "-numa dist,src=source,dst=destination,val=distance\n" 224 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 225 "-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" 226 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 227 QEMU_ARCH_ALL) 228SRST 229``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 230 \ 231``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 232 \ 233``-numa dist,src=source,dst=destination,val=distance`` 234 \ 235``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 236 \ 237``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 238 \ 239``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 240 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 241 distance from a source node to a destination node. Set the ACPI 242 Heterogeneous Memory Attributes for the given nodes. 243 244 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 245 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 246 contiguous range of CPU indexes (or a single VCPU if lastcpu is 247 omitted). A non-contiguous set of VCPUs can be represented by 248 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 249 omitted on all nodes, VCPUs are automatically split between them. 250 251 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 252 NUMA node: 253 254 :: 255 256 -numa node,cpus=0-2,cpus=5 257 258 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 259 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 260 assign CPU objects to a node using topology layout properties of 261 CPU. The set of properties is machine specific, and depends on used 262 machine type/'\ ``smp``\ ' options. It could be queried with 263 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 264 property specifies node to which CPU object will be assigned, it's 265 required for node to be declared with '\ ``node``\ ' option before 266 it's used with '\ ``cpu``\ ' option. 267 268 For example: 269 270 :: 271 272 -M pc \ 273 -smp 1,sockets=2,maxcpus=2 \ 274 -numa node,nodeid=0 -numa node,nodeid=1 \ 275 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 276 277 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 278 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 279 a given memory backend device to a node. If '\ ``mem``\ ' and 280 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 281 282 283 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 284 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 285 use it. 286 287 '\ ``initiator``\ ' is an additional option that points to an 288 initiator NUMA node that has best performance (the lowest latency or 289 largest bandwidth) to this NUMA node. Note that this option can be 290 set only when the machine property 'hmat' is set to 'on'. 291 292 Following example creates a machine with 2 NUMA nodes, node 0 has 293 CPU. node 1 has only memory, and its initiator is node 0. Note that 294 because node 0 has CPU, by default the initiator of node 0 is itself 295 and must be itself. 296 297 :: 298 299 -machine hmat=on \ 300 -m 2G,slots=2,maxmem=4G \ 301 -object memory-backend-ram,size=1G,id=m0 \ 302 -object memory-backend-ram,size=1G,id=m1 \ 303 -numa node,nodeid=0,memdev=m0 \ 304 -numa node,nodeid=1,memdev=m1,initiator=0 \ 305 -smp 2,sockets=2,maxcpus=2 \ 306 -numa cpu,node-id=0,socket-id=0 \ 307 -numa cpu,node-id=0,socket-id=1 308 309 source and destination are NUMA node IDs. distance is the NUMA 310 distance from source to destination. The distance from a node to 311 itself is always 10. If any pair of nodes is given a distance, then 312 all pairs must be given distances. Although, when distances are only 313 given in one direction for each pair of nodes, then the distances in 314 the opposite directions are assumed to be the same. If, however, an 315 asymmetrical pair of distances is given for even one node pair, then 316 all node pairs must be provided distance values for both directions, 317 even when they are symmetrical. When a node is unreachable from 318 another node, set the pair's distance to 255. 319 320 Note that the -``numa`` option doesn't allocate any of the specified 321 resources, it just assigns existing resources to NUMA nodes. This 322 means that one still has to use the ``-m``, ``-smp`` options to 323 allocate RAM and VCPUs respectively. 324 325 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 326 Information between initiator and target NUMA nodes in ACPI 327 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 328 create memory requests, usually it has one or more processors. 329 Target NUMA node contains addressable memory. 330 331 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 332 the memory hierarchy of the target NUMA node: if hierarchy is 333 'memory', the structure represents the memory performance; if 334 hierarchy is 'first-level\|second-level\|third-level', this 335 structure represents aggregated performance of memory side caches 336 for each domain. type of 'data-type' is type of data represented by 337 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 338 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 339 the target memory; if 'hierarchy' is 340 'first-level\|second-level\|third-level', 'data-type' is 341 'access\|read\|write' hit latency or 'access\|read\|write' hit 342 bandwidth of the target memory side cache. 343 344 lat is latency value in nanoseconds. bw is bandwidth value, the 345 possible value and units are NUM[M\|G\|T], mean that the bandwidth 346 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 347 used suffix). Note that if latency or bandwidth value is 0, means 348 the corresponding latency or bandwidth information is not provided. 349 350 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 351 belongs. size is the size of memory side cache in bytes. level is 352 the cache level described in this structure, note that the cache 353 level 0 should not be used with '\ ``hmat-cache``\ ' option. 354 associativity is the cache associativity, the possible value is 355 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 356 is the write policy. line is the cache Line size in bytes. 357 358 For example, the following options describe 2 NUMA nodes. Node 0 has 359 2 cpus and a ram, node 1 has only a ram. The processors in node 0 360 access memory in node 0 with access-latency 5 nanoseconds, 361 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 362 memory in NUMA node 1 with access-latency 10 nanoseconds, 363 access-bandwidth is 100 MB/s. And for memory side cache information, 364 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 365 policy is write-back, the cache Line size is 8 bytes: 366 367 :: 368 369 -machine hmat=on \ 370 -m 2G \ 371 -object memory-backend-ram,size=1G,id=m0 \ 372 -object memory-backend-ram,size=1G,id=m1 \ 373 -smp 2 \ 374 -numa node,nodeid=0,memdev=m0 \ 375 -numa node,nodeid=1,memdev=m1,initiator=0 \ 376 -numa cpu,node-id=0,socket-id=0 \ 377 -numa cpu,node-id=0,socket-id=1 \ 378 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 379 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 380 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 381 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 382 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 383 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 384ERST 385 386DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 387 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 388 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 389SRST 390``-add-fd fd=fd,set=set[,opaque=opaque]`` 391 Add a file descriptor to an fd set. Valid options are: 392 393 ``fd=fd`` 394 This option defines the file descriptor of which a duplicate is 395 added to fd set. The file descriptor cannot be stdin, stdout, or 396 stderr. 397 398 ``set=set`` 399 This option defines the ID of the fd set to add the file 400 descriptor to. 401 402 ``opaque=opaque`` 403 This option defines a free-form string that can be used to 404 describe fd. 405 406 You can open an image using pre-opened file descriptors from an fd 407 set: 408 409 .. parsed-literal:: 410 411 |qemu_system| \\ 412 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 413 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 414 -drive file=/dev/fdset/2,index=0,media=disk 415ERST 416 417DEF("set", HAS_ARG, QEMU_OPTION_set, 418 "-set group.id.arg=value\n" 419 " set <arg> parameter for item <id> of type <group>\n" 420 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 421SRST 422``-set group.id.arg=value`` 423 Set parameter arg for item id of type group 424ERST 425 426DEF("global", HAS_ARG, QEMU_OPTION_global, 427 "-global driver.property=value\n" 428 "-global driver=driver,property=property,value=value\n" 429 " set a global default for a driver property\n", 430 QEMU_ARCH_ALL) 431SRST 432``-global driver.prop=value`` 433 \ 434``-global driver=driver,property=property,value=value`` 435 Set default value of driver's property prop to value, e.g.: 436 437 .. parsed-literal:: 438 439 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 440 441 In particular, you can use this to set driver properties for devices 442 which are created automatically by the machine model. To create a 443 device which is not created automatically and set properties on it, 444 use -``device``. 445 446 -global driver.prop=value is shorthand for -global 447 driver=driver,property=prop,value=value. The longhand syntax works 448 even when driver contains a dot. 449ERST 450 451DEF("boot", HAS_ARG, QEMU_OPTION_boot, 452 "-boot [order=drives][,once=drives][,menu=on|off]\n" 453 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 454 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 455 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 456 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 457 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 458 QEMU_ARCH_ALL) 459SRST 460``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 461 Specify boot order drives as a string of drive letters. Valid drive 462 letters depend on the target architecture. The x86 PC uses: a, b 463 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 464 (Etherboot from network adapter 1-4), hard disk boot is the default. 465 To apply a particular boot order only on the first startup, specify 466 it via ``once``. Note that the ``order`` or ``once`` parameter 467 should not be used together with the ``bootindex`` property of 468 devices, since the firmware implementations normally do not support 469 both at the same time. 470 471 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 472 as firmware/BIOS supports them. The default is non-interactive boot. 473 474 A splash picture could be passed to bios, enabling user to show it 475 as logo, when option splash=sp\_name is given and menu=on, If 476 firmware/BIOS supports them. Currently Seabios for X86 system 477 support it. limitation: The splash file could be a jpeg file or a 478 BMP file in 24 BPP format(true color). The resolution should be 479 supported by the SVGA mode, so the recommended is 320x240, 640x480, 480 800x640. 481 482 A timeout could be passed to bios, guest will pause for rb\_timeout 483 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 484 not reboot, qemu passes '-1' to bios by default. Currently Seabios 485 for X86 system support it. 486 487 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 488 it. This only effects when boot priority is changed by bootindex 489 options. The default is non-strict boot. 490 491 .. parsed-literal:: 492 493 # try to boot from network first, then from hard disk 494 |qemu_system_x86| -boot order=nc 495 # boot from CD-ROM first, switch back to default order after reboot 496 |qemu_system_x86| -boot once=d 497 # boot with a splash picture for 5 seconds. 498 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 499 500 Note: The legacy format '-boot drives' is still supported but its 501 use is discouraged as it may be removed from future versions. 502ERST 503 504DEF("m", HAS_ARG, QEMU_OPTION_m, 505 "-m [size=]megs[,slots=n,maxmem=size]\n" 506 " configure guest RAM\n" 507 " size: initial amount of guest memory\n" 508 " slots: number of hotplug slots (default: none)\n" 509 " maxmem: maximum amount of guest memory (default: none)\n" 510 "NOTE: Some architectures might enforce a specific granularity\n", 511 QEMU_ARCH_ALL) 512SRST 513``-m [size=]megs[,slots=n,maxmem=size]`` 514 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 515 Optionally, a suffix of "M" or "G" can be used to signify a value in 516 megabytes or gigabytes respectively. Optional pair slots, maxmem 517 could be used to set amount of hotpluggable memory slots and maximum 518 amount of memory. Note that maxmem must be aligned to the page size. 519 520 For example, the following command-line sets the guest startup RAM 521 size to 1GB, creates 3 slots to hotplug additional memory and sets 522 the maximum memory the guest can reach to 4GB: 523 524 .. parsed-literal:: 525 526 |qemu_system| -m 1G,slots=3,maxmem=4G 527 528 If slots and maxmem are not specified, memory hotplug won't be 529 enabled and the guest startup RAM will never increase. 530ERST 531 532DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 533 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 534SRST 535``-mem-path path`` 536 Allocate guest RAM from a temporarily created file in path. 537ERST 538 539DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 540 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 541 QEMU_ARCH_ALL) 542SRST 543``-mem-prealloc`` 544 Preallocate memory when using -mem-path. 545ERST 546 547DEF("k", HAS_ARG, QEMU_OPTION_k, 548 "-k language use keyboard layout (for example 'fr' for French)\n", 549 QEMU_ARCH_ALL) 550SRST 551``-k language`` 552 Use keyboard layout language (for example ``fr`` for French). This 553 option is only needed where it is not easy to get raw PC keycodes 554 (e.g. on Macs, with some X11 servers or with a VNC or curses 555 display). You don't normally need to use it on PC/Linux or 556 PC/Windows hosts. 557 558 The available layouts are: 559 560 :: 561 562 ar de-ch es fo fr-ca hu ja mk no pt-br sv 563 da en-gb et fr fr-ch is lt nl pl ru th 564 de en-us fi fr-be hr it lv nl-be pt sl tr 565 566 The default is ``en-us``. 567ERST 568 569 570HXCOMM Deprecated by -audiodev 571DEF("audio-help", 0, QEMU_OPTION_audio_help, 572 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 573 QEMU_ARCH_ALL) 574SRST 575``-audio-help`` 576 Will show the -audiodev equivalent of the currently specified 577 (deprecated) environment variables. 578ERST 579 580DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 581 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 582 " specifies the audio backend to use\n" 583 " id= identifier of the backend\n" 584 " timer-period= timer period in microseconds\n" 585 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 586 " in|out.fixed-settings= use fixed settings for host audio\n" 587 " in|out.frequency= frequency to use with fixed settings\n" 588 " in|out.channels= number of channels to use with fixed settings\n" 589 " in|out.format= sample format to use with fixed settings\n" 590 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 591 " in|out.voices= number of voices to use\n" 592 " in|out.buffer-length= length of buffer in microseconds\n" 593 "-audiodev none,id=id,[,prop[=value][,...]]\n" 594 " dummy driver that discards all output\n" 595#ifdef CONFIG_AUDIO_ALSA 596 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 597 " in|out.dev= name of the audio device to use\n" 598 " in|out.period-length= length of period in microseconds\n" 599 " in|out.try-poll= attempt to use poll mode\n" 600 " threshold= threshold (in microseconds) when playback starts\n" 601#endif 602#ifdef CONFIG_AUDIO_COREAUDIO 603 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 604 " in|out.buffer-count= number of buffers\n" 605#endif 606#ifdef CONFIG_AUDIO_DSOUND 607 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 608 " latency= add extra latency to playback in microseconds\n" 609#endif 610#ifdef CONFIG_AUDIO_OSS 611 "-audiodev oss,id=id[,prop[=value][,...]]\n" 612 " in|out.dev= path of the audio device to use\n" 613 " in|out.buffer-count= number of buffers\n" 614 " in|out.try-poll= attempt to use poll mode\n" 615 " try-mmap= try using memory mapped access\n" 616 " exclusive= open device in exclusive mode\n" 617 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 618#endif 619#ifdef CONFIG_AUDIO_PA 620 "-audiodev pa,id=id[,prop[=value][,...]]\n" 621 " server= PulseAudio server address\n" 622 " in|out.name= source/sink device name\n" 623 " in|out.latency= desired latency in microseconds\n" 624#endif 625#ifdef CONFIG_AUDIO_SDL 626 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 627 " in|out.buffer-count= number of buffers\n" 628#endif 629#ifdef CONFIG_SPICE 630 "-audiodev spice,id=id[,prop[=value][,...]]\n" 631#endif 632 "-audiodev wav,id=id[,prop[=value][,...]]\n" 633 " path= path of wav file to record\n", 634 QEMU_ARCH_ALL) 635SRST 636``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 637 Adds a new audio backend driver identified by id. There are global 638 and driver specific properties. Some values can be set differently 639 for input and output, they're marked with ``in|out.``. You can set 640 the input's property with ``in.prop`` and the output's property with 641 ``out.prop``. For example: 642 643 :: 644 645 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 646 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 647 648 NOTE: parameter validation is known to be incomplete, in many cases 649 specifying an invalid option causes QEMU to print an error message 650 and continue emulation without sound. 651 652 Valid global options are: 653 654 ``id=identifier`` 655 Identifies the audio backend. 656 657 ``timer-period=period`` 658 Sets the timer period used by the audio subsystem in 659 microseconds. Default is 10000 (10 ms). 660 661 ``in|out.mixing-engine=on|off`` 662 Use QEMU's mixing engine to mix all streams inside QEMU and 663 convert audio formats when not supported by the backend. When 664 off, fixed-settings must be off too. Note that disabling this 665 option means that the selected backend must support multiple 666 streams and the audio formats used by the virtual cards, 667 otherwise you'll get no sound. It's not recommended to disable 668 this option unless you want to use 5.1 or 7.1 audio, as mixing 669 engine only supports mono and stereo audio. Default is on. 670 671 ``in|out.fixed-settings=on|off`` 672 Use fixed settings for host audio. When off, it will change 673 based on how the guest opens the sound card. In this case you 674 must not specify frequency, channels or format. Default is on. 675 676 ``in|out.frequency=frequency`` 677 Specify the frequency to use when using fixed-settings. Default 678 is 44100Hz. 679 680 ``in|out.channels=channels`` 681 Specify the number of channels to use when using fixed-settings. 682 Default is 2 (stereo). 683 684 ``in|out.format=format`` 685 Specify the sample format to use when using fixed-settings. 686 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 687 ``u32``, ``f32``. Default is ``s16``. 688 689 ``in|out.voices=voices`` 690 Specify the number of voices to use. Default is 1. 691 692 ``in|out.buffer-length=usecs`` 693 Sets the size of the buffer in microseconds. 694 695``-audiodev none,id=id[,prop[=value][,...]]`` 696 Creates a dummy backend that discards all outputs. This backend has 697 no backend specific properties. 698 699``-audiodev alsa,id=id[,prop[=value][,...]]`` 700 Creates backend using the ALSA. This backend is only available on 701 Linux. 702 703 ALSA specific options are: 704 705 ``in|out.dev=device`` 706 Specify the ALSA device to use for input and/or output. Default 707 is ``default``. 708 709 ``in|out.period-length=usecs`` 710 Sets the period length in microseconds. 711 712 ``in|out.try-poll=on|off`` 713 Attempt to use poll mode with the device. Default is on. 714 715 ``threshold=threshold`` 716 Threshold (in microseconds) when playback starts. Default is 0. 717 718``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 719 Creates a backend using Apple's Core Audio. This backend is only 720 available on Mac OS and only supports playback. 721 722 Core Audio specific options are: 723 724 ``in|out.buffer-count=count`` 725 Sets the count of the buffers. 726 727``-audiodev dsound,id=id[,prop[=value][,...]]`` 728 Creates a backend using Microsoft's DirectSound. This backend is 729 only available on Windows and only supports playback. 730 731 DirectSound specific options are: 732 733 ``latency=usecs`` 734 Add extra usecs microseconds latency to playback. Default is 735 10000 (10 ms). 736 737``-audiodev oss,id=id[,prop[=value][,...]]`` 738 Creates a backend using OSS. This backend is available on most 739 Unix-like systems. 740 741 OSS specific options are: 742 743 ``in|out.dev=device`` 744 Specify the file name of the OSS device to use. Default is 745 ``/dev/dsp``. 746 747 ``in|out.buffer-count=count`` 748 Sets the count of the buffers. 749 750 ``in|out.try-poll=on|of`` 751 Attempt to use poll mode with the device. Default is on. 752 753 ``try-mmap=on|off`` 754 Try using memory mapped device access. Default is off. 755 756 ``exclusive=on|off`` 757 Open the device in exclusive mode (vmix won't work in this 758 case). Default is off. 759 760 ``dsp-policy=policy`` 761 Sets the timing policy (between 0 and 10, where smaller number 762 means smaller latency but higher CPU usage). Use -1 to use 763 buffer sizes specified by ``buffer`` and ``buffer-count``. This 764 option is ignored if you do not have OSS 4. Default is 5. 765 766``-audiodev pa,id=id[,prop[=value][,...]]`` 767 Creates a backend using PulseAudio. This backend is available on 768 most systems. 769 770 PulseAudio specific options are: 771 772 ``server=server`` 773 Sets the PulseAudio server to connect to. 774 775 ``in|out.name=sink`` 776 Use the specified source/sink for recording/playback. 777 778 ``in|out.latency=usecs`` 779 Desired latency in microseconds. The PulseAudio server will try 780 to honor this value but actual latencies may be lower or higher. 781 782``-audiodev sdl,id=id[,prop[=value][,...]]`` 783 Creates a backend using SDL. This backend is available on most 784 systems, but you should use your platform's native backend if 785 possible. 786 787 SDL specific options are: 788 789 ``in|out.buffer-count=count`` 790 Sets the count of the buffers. 791 792``-audiodev spice,id=id[,prop[=value][,...]]`` 793 Creates a backend that sends audio through SPICE. This backend 794 requires ``-spice`` and automatically selected in that case, so 795 usually you can ignore this option. This backend has no backend 796 specific properties. 797 798``-audiodev wav,id=id[,prop[=value][,...]]`` 799 Creates a backend that writes audio to a WAV file. 800 801 Backend specific options are: 802 803 ``path=path`` 804 Write recorded audio into the specified file. Default is 805 ``qemu.wav``. 806ERST 807 808DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 809 "-soundhw c1,... enable audio support\n" 810 " and only specified sound cards (comma separated list)\n" 811 " use '-soundhw help' to get the list of supported cards\n" 812 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 813SRST 814``-soundhw card1[,card2,...] or -soundhw all`` 815 Enable audio and selected sound hardware. Use 'help' to print all 816 available sound hardware. For example: 817 818 .. parsed-literal:: 819 820 |qemu_system_x86| -soundhw sb16,adlib disk.img 821 |qemu_system_x86| -soundhw es1370 disk.img 822 |qemu_system_x86| -soundhw ac97 disk.img 823 |qemu_system_x86| -soundhw hda disk.img 824 |qemu_system_x86| -soundhw all disk.img 825 |qemu_system_x86| -soundhw help 826 827 Note that Linux's i810\_audio OSS kernel (for AC97) module might 828 require manually specifying clocking. 829 830 :: 831 832 modprobe i810_audio clocking=48000 833ERST 834 835DEF("device", HAS_ARG, QEMU_OPTION_device, 836 "-device driver[,prop[=value][,...]]\n" 837 " add device (based on driver)\n" 838 " prop=value,... sets driver properties\n" 839 " use '-device help' to print all possible drivers\n" 840 " use '-device driver,help' to print all possible properties\n", 841 QEMU_ARCH_ALL) 842SRST 843``-device driver[,prop[=value][,...]]`` 844 Add device driver. prop=value sets driver properties. Valid 845 properties depend on the driver. To get help on possible drivers and 846 properties, use ``-device help`` and ``-device driver,help``. 847 848 Some drivers are: 849 850``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 851 Add an IPMI BMC. This is a simulation of a hardware management 852 interface processor that normally sits on a system. It provides a 853 watchdog and the ability to reset and power control the system. You 854 need to connect this to an IPMI interface to make it useful 855 856 The IPMI slave address to use for the BMC. The default is 0x20. This 857 address is the BMC's address on the I2C network of management 858 controllers. If you don't know what this means, it is safe to ignore 859 it. 860 861 ``id=id`` 862 The BMC id for interfaces to use this device. 863 864 ``slave_addr=val`` 865 Define slave address to use for the BMC. The default is 0x20. 866 867 ``sdrfile=file`` 868 file containing raw Sensor Data Records (SDR) data. The default 869 is none. 870 871 ``fruareasize=val`` 872 size of a Field Replaceable Unit (FRU) area. The default is 873 1024. 874 875 ``frudatafile=file`` 876 file containing raw Field Replaceable Unit (FRU) inventory data. 877 The default is none. 878 879 ``guid=uuid`` 880 value for the GUID for the BMC, in standard UUID format. If this 881 is set, get "Get GUID" command to the BMC will return it. 882 Otherwise "Get GUID" will return an error. 883 884``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 885 Add a connection to an external IPMI BMC simulator. Instead of 886 locally emulating the BMC like the above item, instead connect to an 887 external entity that provides the IPMI services. 888 889 A connection is made to an external BMC simulator. If you do this, 890 it is strongly recommended that you use the "reconnect=" chardev 891 option to reconnect to the simulator if the connection is lost. Note 892 that if this is not used carefully, it can be a security issue, as 893 the interface has the ability to send resets, NMIs, and power off 894 the VM. It's best if QEMU makes a connection to an external 895 simulator running on a secure port on localhost, so neither the 896 simulator nor QEMU is exposed to any outside network. 897 898 See the "lanserv/README.vm" file in the OpenIPMI library for more 899 details on the external interface. 900 901``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 902 Add a KCS IPMI interafce on the ISA bus. This also adds a 903 corresponding ACPI and SMBIOS entries, if appropriate. 904 905 ``bmc=id`` 906 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 907 above. 908 909 ``ioport=val`` 910 Define the I/O address of the interface. The default is 0xca0 911 for KCS. 912 913 ``irq=val`` 914 Define the interrupt to use. The default is 5. To disable 915 interrupts, set this to 0. 916 917``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 918 Like the KCS interface, but defines a BT interface. The default port 919 is 0xe4 and the default interrupt is 5. 920 921``-device pci-ipmi-kcs,bmc=id`` 922 Add a KCS IPMI interafce on the PCI bus. 923 924 ``bmc=id`` 925 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 926 927``-device pci-ipmi-bt,bmc=id`` 928 Like the KCS interface, but defines a BT interface on the PCI bus. 929ERST 930 931DEF("name", HAS_ARG, QEMU_OPTION_name, 932 "-name string1[,process=string2][,debug-threads=on|off]\n" 933 " set the name of the guest\n" 934 " string1 sets the window title and string2 the process name\n" 935 " When debug-threads is enabled, individual threads are given a separate name\n" 936 " NOTE: The thread names are for debugging and not a stable API.\n", 937 QEMU_ARCH_ALL) 938SRST 939``-name name`` 940 Sets the name of the guest. This name will be displayed in the SDL 941 window caption. The name will also be used for the VNC server. Also 942 optionally set the top visible process name in Linux. Naming of 943 individual threads can also be enabled on Linux to aid debugging. 944ERST 945 946DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 947 "-uuid %08x-%04x-%04x-%04x-%012x\n" 948 " specify machine UUID\n", QEMU_ARCH_ALL) 949SRST 950``-uuid uuid`` 951 Set system UUID. 952ERST 953 954DEFHEADING() 955 956DEFHEADING(Block device options:) 957 958DEF("fda", HAS_ARG, QEMU_OPTION_fda, 959 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 960DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 961SRST 962``-fda file`` 963 \ 964``-fdb file`` 965 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 966 the System Emulation Users Guide). 967ERST 968 969DEF("hda", HAS_ARG, QEMU_OPTION_hda, 970 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 971DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 972DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 973 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 974DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 975SRST 976``-hda file`` 977 \ 978``-hdb file`` 979 \ 980``-hdc file`` 981 \ 982``-hdd file`` 983 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 984 chapter in the System Emulation Users Guide). 985ERST 986 987DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 988 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 989 QEMU_ARCH_ALL) 990SRST 991``-cdrom file`` 992 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 993 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 994 as filename. 995ERST 996 997DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 998 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 999 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1000 " [,read-only=on|off][,auto-read-only=on|off]\n" 1001 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1002 " [,driver specific parameters...]\n" 1003 " configure a block backend\n", QEMU_ARCH_ALL) 1004SRST 1005``-blockdev option[,option[,option[,...]]]`` 1006 Define a new block driver node. Some of the options apply to all 1007 block drivers, other options are only accepted for a specific block 1008 driver. See below for a list of generic options and options for the 1009 most common block drivers. 1010 1011 Options that expect a reference to another node (e.g. ``file``) can 1012 be given in two ways. Either you specify the node name of an already 1013 existing node (file=node-name), or you define a new node inline, 1014 adding options for the referenced node after a dot 1015 (file.filename=path,file.aio=native). 1016 1017 A block driver node created with ``-blockdev`` can be used for a 1018 guest device by specifying its node name for the ``drive`` property 1019 in a ``-device`` argument that defines a block device. 1020 1021 ``Valid options for any block driver node:`` 1022 ``driver`` 1023 Specifies the block driver to use for the given node. 1024 1025 ``node-name`` 1026 This defines the name of the block driver node by which it 1027 will be referenced later. The name must be unique, i.e. it 1028 must not match the name of a different block driver node, or 1029 (if you use ``-drive`` as well) the ID of a drive. 1030 1031 If no node name is specified, it is automatically generated. 1032 The generated node name is not intended to be predictable 1033 and changes between QEMU invocations. For the top level, an 1034 explicit node name must be specified. 1035 1036 ``read-only`` 1037 Open the node read-only. Guest write attempts will fail. 1038 1039 Note that some block drivers support only read-only access, 1040 either generally or in certain configurations. In this case, 1041 the default value ``read-only=off`` does not work and the 1042 option must be specified explicitly. 1043 1044 ``auto-read-only`` 1045 If ``auto-read-only=on`` is set, QEMU may fall back to 1046 read-only usage even when ``read-only=off`` is requested, or 1047 even switch between modes as needed, e.g. depending on 1048 whether the image file is writable or whether a writing user 1049 is attached to the node. 1050 1051 ``force-share`` 1052 Override the image locking system of QEMU by forcing the 1053 node to utilize weaker shared access for permissions where 1054 it would normally request exclusive access. When there is 1055 the potential for multiple instances to have the same file 1056 open (whether this invocation of QEMU is the first or the 1057 second instance), both instances must permit shared access 1058 for the second instance to succeed at opening the file. 1059 1060 Enabling ``force-share=on`` requires ``read-only=on``. 1061 1062 ``cache.direct`` 1063 The host page cache can be avoided with ``cache.direct=on``. 1064 This will attempt to do disk IO directly to the guest's 1065 memory. QEMU may still perform an internal copy of the data. 1066 1067 ``cache.no-flush`` 1068 In case you don't care about data integrity over host 1069 failures, you can use ``cache.no-flush=on``. This option 1070 tells QEMU that it never needs to write any data to the disk 1071 but can instead keep things in cache. If anything goes 1072 wrong, like your host losing power, the disk storage getting 1073 disconnected accidentally, etc. your image will most 1074 probably be rendered unusable. 1075 1076 ``discard=discard`` 1077 discard is one of "ignore" (or "off") or "unmap" (or "on") 1078 and controls whether ``discard`` (also known as ``trim`` or 1079 ``unmap``) requests are ignored or passed to the filesystem. 1080 Some machine types may not support discard requests. 1081 1082 ``detect-zeroes=detect-zeroes`` 1083 detect-zeroes is "off", "on" or "unmap" and enables the 1084 automatic conversion of plain zero writes by the OS to 1085 driver specific optimized zero write commands. You may even 1086 choose "unmap" if discard is set to "unmap" to allow a zero 1087 write to be converted to an ``unmap`` operation. 1088 1089 ``Driver-specific options for file`` 1090 This is the protocol-level block driver for accessing regular 1091 files. 1092 1093 ``filename`` 1094 The path to the image file in the local filesystem 1095 1096 ``aio`` 1097 Specifies the AIO backend (threads/native/io_uring, 1098 default: threads) 1099 1100 ``locking`` 1101 Specifies whether the image file is protected with Linux OFD 1102 / POSIX locks. The default is to use the Linux Open File 1103 Descriptor API if available, otherwise no lock is applied. 1104 (auto/on/off, default: auto) 1105 1106 Example: 1107 1108 :: 1109 1110 -blockdev driver=file,node-name=disk,filename=disk.img 1111 1112 ``Driver-specific options for raw`` 1113 This is the image format block driver for raw images. It is 1114 usually stacked on top of a protocol level block driver such as 1115 ``file``. 1116 1117 ``file`` 1118 Reference to or definition of the data source block driver 1119 node (e.g. a ``file`` driver node) 1120 1121 Example 1: 1122 1123 :: 1124 1125 -blockdev driver=file,node-name=disk_file,filename=disk.img 1126 -blockdev driver=raw,node-name=disk,file=disk_file 1127 1128 Example 2: 1129 1130 :: 1131 1132 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1133 1134 ``Driver-specific options for qcow2`` 1135 This is the image format block driver for qcow2 images. It is 1136 usually stacked on top of a protocol level block driver such as 1137 ``file``. 1138 1139 ``file`` 1140 Reference to or definition of the data source block driver 1141 node (e.g. a ``file`` driver node) 1142 1143 ``backing`` 1144 Reference to or definition of the backing file block device 1145 (default is taken from the image file). It is allowed to 1146 pass ``null`` here in order to disable the default backing 1147 file. 1148 1149 ``lazy-refcounts`` 1150 Whether to enable the lazy refcounts feature (on/off; 1151 default is taken from the image file) 1152 1153 ``cache-size`` 1154 The maximum total size of the L2 table and refcount block 1155 caches in bytes (default: the sum of l2-cache-size and 1156 refcount-cache-size) 1157 1158 ``l2-cache-size`` 1159 The maximum size of the L2 table cache in bytes (default: if 1160 cache-size is not specified - 32M on Linux platforms, and 8M 1161 on non-Linux platforms; otherwise, as large as possible 1162 within the cache-size, while permitting the requested or the 1163 minimal refcount cache size) 1164 1165 ``refcount-cache-size`` 1166 The maximum size of the refcount block cache in bytes 1167 (default: 4 times the cluster size; or if cache-size is 1168 specified, the part of it which is not used for the L2 1169 cache) 1170 1171 ``cache-clean-interval`` 1172 Clean unused entries in the L2 and refcount caches. The 1173 interval is in seconds. The default value is 600 on 1174 supporting platforms, and 0 on other platforms. Setting it 1175 to 0 disables this feature. 1176 1177 ``pass-discard-request`` 1178 Whether discard requests to the qcow2 device should be 1179 forwarded to the data source (on/off; default: on if 1180 discard=unmap is specified, off otherwise) 1181 1182 ``pass-discard-snapshot`` 1183 Whether discard requests for the data source should be 1184 issued when a snapshot operation (e.g. deleting a snapshot) 1185 frees clusters in the qcow2 file (on/off; default: on) 1186 1187 ``pass-discard-other`` 1188 Whether discard requests for the data source should be 1189 issued on other occasions where a cluster gets freed 1190 (on/off; default: off) 1191 1192 ``overlap-check`` 1193 Which overlap checks to perform for writes to the image 1194 (none/constant/cached/all; default: cached). For details or 1195 finer granularity control refer to the QAPI documentation of 1196 ``blockdev-add``. 1197 1198 Example 1: 1199 1200 :: 1201 1202 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1203 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1204 1205 Example 2: 1206 1207 :: 1208 1209 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1210 1211 ``Driver-specific options for other drivers`` 1212 Please refer to the QAPI documentation of the ``blockdev-add`` 1213 QMP command. 1214ERST 1215 1216DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1217 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1218 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1219 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1220 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1221 " [,aio=threads|native|io_uring]\n" 1222 " [,readonly=on|off][,copy-on-read=on|off]\n" 1223 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1224 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1225 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1226 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1227 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1228 " [[,iops_size=is]]\n" 1229 " [[,group=g]]\n" 1230 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1231SRST 1232``-drive option[,option[,option[,...]]]`` 1233 Define a new drive. This includes creating a block driver node (the 1234 backend) as well as a guest device, and is mostly a shortcut for 1235 defining the corresponding ``-blockdev`` and ``-device`` options. 1236 1237 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1238 In addition, it knows the following options: 1239 1240 ``file=file`` 1241 This option defines which disk image (see the :ref:`disk images` 1242 chapter in the System Emulation Users Guide) to use with this drive. 1243 If the filename contains comma, you must double it (for instance, 1244 "file=my,,file" to use file "my,file"). 1245 1246 Special files such as iSCSI devices can be specified using 1247 protocol specific URLs. See the section for "Device URL Syntax" 1248 for more information. 1249 1250 ``if=interface`` 1251 This option defines on which type on interface the drive is 1252 connected. Available types are: ide, scsi, sd, mtd, floppy, 1253 pflash, virtio, none. 1254 1255 ``bus=bus,unit=unit`` 1256 These options define where is connected the drive by defining 1257 the bus number and the unit id. 1258 1259 ``index=index`` 1260 This option defines where is connected the drive by using an 1261 index in the list of available connectors of a given interface 1262 type. 1263 1264 ``media=media`` 1265 This option defines the type of the media: disk or cdrom. 1266 1267 ``snapshot=snapshot`` 1268 snapshot is "on" or "off" and controls snapshot mode for the 1269 given drive (see ``-snapshot``). 1270 1271 ``cache=cache`` 1272 cache is "none", "writeback", "unsafe", "directsync" or 1273 "writethrough" and controls how the host cache is used to access 1274 block data. This is a shortcut that sets the ``cache.direct`` 1275 and ``cache.no-flush`` options (as in ``-blockdev``), and 1276 additionally ``cache.writeback``, which provides a default for 1277 the ``write-cache`` option of block guest devices (as in 1278 ``-device``). The modes correspond to the following settings: 1279 1280 ============= =============== ============ ============== 1281 \ cache.writeback cache.direct cache.no-flush 1282 ============= =============== ============ ============== 1283 writeback on off off 1284 none on on off 1285 writethrough off off off 1286 directsync off on off 1287 unsafe on off on 1288 ============= =============== ============ ============== 1289 1290 The default mode is ``cache=writeback``. 1291 1292 ``aio=aio`` 1293 aio is "threads", "native", or "io_uring" and selects between pthread 1294 based disk I/O, native Linux AIO, or Linux io_uring API. 1295 1296 ``format=format`` 1297 Specify which disk format will be used rather than detecting the 1298 format. Can be used to specify format=raw to avoid interpreting 1299 an untrusted format header. 1300 1301 ``werror=action,rerror=action`` 1302 Specify which action to take on write and read errors. Valid 1303 actions are: "ignore" (ignore the error and try to continue), 1304 "stop" (pause QEMU), "report" (report the error to the guest), 1305 "enospc" (pause QEMU only if the host disk is full; report the 1306 error to the guest otherwise). The default setting is 1307 ``werror=enospc`` and ``rerror=report``. 1308 1309 ``copy-on-read=copy-on-read`` 1310 copy-on-read is "on" or "off" and enables whether to copy read 1311 backing file sectors into the image file. 1312 1313 ``bps=b,bps_rd=r,bps_wr=w`` 1314 Specify bandwidth throttling limits in bytes per second, either 1315 for all request types or for reads or writes only. Small values 1316 can lead to timeouts or hangs inside the guest. A safe minimum 1317 for disks is 2 MB/s. 1318 1319 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1320 Specify bursts in bytes per second, either for all request types 1321 or for reads or writes only. Bursts allow the guest I/O to spike 1322 above the limit temporarily. 1323 1324 ``iops=i,iops_rd=r,iops_wr=w`` 1325 Specify request rate limits in requests per second, either for 1326 all request types or for reads or writes only. 1327 1328 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1329 Specify bursts in requests per second, either for all request 1330 types or for reads or writes only. Bursts allow the guest I/O to 1331 spike above the limit temporarily. 1332 1333 ``iops_size=is`` 1334 Let every is bytes of a request count as a new request for iops 1335 throttling purposes. Use this option to prevent guests from 1336 circumventing iops limits by sending fewer but larger requests. 1337 1338 ``group=g`` 1339 Join a throttling quota group with given name g. All drives that 1340 are members of the same group are accounted for together. Use 1341 this option to prevent guests from circumventing throttling 1342 limits by using many small disks instead of a single larger 1343 disk. 1344 1345 By default, the ``cache.writeback=on`` mode is used. It will report 1346 data writes as completed as soon as the data is present in the host 1347 page cache. This is safe as long as your guest OS makes sure to 1348 correctly flush disk caches where needed. If your guest OS does not 1349 handle volatile disk write caches correctly and your host crashes or 1350 loses power, then the guest may experience data corruption. 1351 1352 For such guests, you should consider using ``cache.writeback=off``. 1353 This means that the host page cache will be used to read and write 1354 data, but write notification will be sent to the guest only after 1355 QEMU has made sure to flush each write to the disk. Be aware that 1356 this has a major impact on performance. 1357 1358 When using the ``-snapshot`` option, unsafe caching is always used. 1359 1360 Copy-on-read avoids accessing the same backing file sectors 1361 repeatedly and is useful when the backing file is over a slow 1362 network. By default copy-on-read is off. 1363 1364 Instead of ``-cdrom`` you can use: 1365 1366 .. parsed-literal:: 1367 1368 |qemu_system| -drive file=file,index=2,media=cdrom 1369 1370 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1371 1372 .. parsed-literal:: 1373 1374 |qemu_system| -drive file=file,index=0,media=disk 1375 |qemu_system| -drive file=file,index=1,media=disk 1376 |qemu_system| -drive file=file,index=2,media=disk 1377 |qemu_system| -drive file=file,index=3,media=disk 1378 1379 You can open an image using pre-opened file descriptors from an fd 1380 set: 1381 1382 .. parsed-literal:: 1383 1384 |qemu_system| \\ 1385 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1386 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1387 -drive file=/dev/fdset/2,index=0,media=disk 1388 1389 You can connect a CDROM to the slave of ide0: 1390 1391 .. parsed-literal:: 1392 1393 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1394 1395 If you don't specify the "file=" argument, you define an empty 1396 drive: 1397 1398 .. parsed-literal:: 1399 1400 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1401 1402 Instead of ``-fda``, ``-fdb``, you can use: 1403 1404 .. parsed-literal:: 1405 1406 |qemu_system_x86| -drive file=file,index=0,if=floppy 1407 |qemu_system_x86| -drive file=file,index=1,if=floppy 1408 1409 By default, interface is "ide" and index is automatically 1410 incremented: 1411 1412 .. parsed-literal:: 1413 1414 |qemu_system_x86| -drive file=a -drive file=b" 1415 1416 is interpreted like: 1417 1418 .. parsed-literal:: 1419 1420 |qemu_system_x86| -hda a -hdb b 1421ERST 1422 1423DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1424 "-mtdblock file use 'file' as on-board Flash memory image\n", 1425 QEMU_ARCH_ALL) 1426SRST 1427``-mtdblock file`` 1428 Use file as on-board Flash memory image. 1429ERST 1430 1431DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1432 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1433SRST 1434``-sd file`` 1435 Use file as SecureDigital card image. 1436ERST 1437 1438DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1439 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1440SRST 1441``-pflash file`` 1442 Use file as a parallel flash image. 1443ERST 1444 1445DEF("snapshot", 0, QEMU_OPTION_snapshot, 1446 "-snapshot write to temporary files instead of disk image files\n", 1447 QEMU_ARCH_ALL) 1448SRST 1449``-snapshot`` 1450 Write to temporary files instead of disk image files. In this case, 1451 the raw disk image you use is not written back. You can however 1452 force the write back by pressing C-a s (see the :ref:`disk images` 1453 chapter in the System Emulation Users Guide). 1454ERST 1455 1456DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1457 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1458 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1459 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1460 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1461 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1462 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1463 " [[,throttling.iops-size=is]]\n" 1464 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1465 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1466 "-fsdev synth,id=id\n", 1467 QEMU_ARCH_ALL) 1468 1469SRST 1470``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1471 \ 1472``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1473 \ 1474``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1475 \ 1476``-fsdev synth,id=id[,readonly=on]`` 1477 Define a new file system device. Valid options are: 1478 1479 ``local`` 1480 Accesses to the filesystem are done by QEMU. 1481 1482 ``proxy`` 1483 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1484 1485 ``synth`` 1486 Synthetic filesystem, only used by QTests. 1487 1488 ``id=id`` 1489 Specifies identifier for this device. 1490 1491 ``path=path`` 1492 Specifies the export path for the file system device. Files 1493 under this path will be available to the 9p client on the guest. 1494 1495 ``security_model=security_model`` 1496 Specifies the security model to be used for this export path. 1497 Supported security models are "passthrough", "mapped-xattr", 1498 "mapped-file" and "none". In "passthrough" security model, files 1499 are stored using the same credentials as they are created on the 1500 guest. This requires QEMU to run as root. In "mapped-xattr" 1501 security model, some of the file attributes like uid, gid, mode 1502 bits and link target are stored as file attributes. For 1503 "mapped-file" these attributes are stored in the hidden 1504 .virtfs\_metadata directory. Directories exported by this 1505 security model cannot interact with other unix tools. "none" 1506 security model is same as passthrough except the sever won't 1507 report failures if it fails to set file attributes like 1508 ownership. Security model is mandatory only for local fsdriver. 1509 Other fsdrivers (like proxy) don't take security model as a 1510 parameter. 1511 1512 ``writeout=writeout`` 1513 This is an optional argument. The only supported value is 1514 "immediate". This means that host page cache will be used to 1515 read and write data but write notification will be sent to the 1516 guest only when the data has been reported as written by the 1517 storage subsystem. 1518 1519 ``readonly=on`` 1520 Enables exporting 9p share as a readonly mount for guests. By 1521 default read-write access is given. 1522 1523 ``socket=socket`` 1524 Enables proxy filesystem driver to use passed socket file for 1525 communicating with virtfs-proxy-helper(1). 1526 1527 ``sock_fd=sock_fd`` 1528 Enables proxy filesystem driver to use passed socket descriptor 1529 for communicating with virtfs-proxy-helper(1). Usually a helper 1530 like libvirt will create socketpair and pass one of the fds as 1531 sock\_fd. 1532 1533 ``fmode=fmode`` 1534 Specifies the default mode for newly created files on the host. 1535 Works only with security models "mapped-xattr" and 1536 "mapped-file". 1537 1538 ``dmode=dmode`` 1539 Specifies the default mode for newly created directories on the 1540 host. Works only with security models "mapped-xattr" and 1541 "mapped-file". 1542 1543 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1544 Specify bandwidth throttling limits in bytes per second, either 1545 for all request types or for reads or writes only. 1546 1547 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1548 Specify bursts in bytes per second, either for all request types 1549 or for reads or writes only. Bursts allow the guest I/O to spike 1550 above the limit temporarily. 1551 1552 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1553 Specify request rate limits in requests per second, either for 1554 all request types or for reads or writes only. 1555 1556 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1557 Specify bursts in requests per second, either for all request 1558 types or for reads or writes only. Bursts allow the guest I/O to 1559 spike above the limit temporarily. 1560 1561 ``throttling.iops-size=is`` 1562 Let every is bytes of a request count as a new request for iops 1563 throttling purposes. 1564 1565 -fsdev option is used along with -device driver "virtio-9p-...". 1566 1567``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1568 Options for virtio-9p-... driver are: 1569 1570 ``type`` 1571 Specifies the variant to be used. Supported values are "pci", 1572 "ccw" or "device", depending on the machine type. 1573 1574 ``fsdev=id`` 1575 Specifies the id value specified along with -fsdev option. 1576 1577 ``mount_tag=mount_tag`` 1578 Specifies the tag name to be used by the guest to mount this 1579 export point. 1580ERST 1581 1582DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1583 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1584 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1585 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1586 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1587 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1588 QEMU_ARCH_ALL) 1589 1590SRST 1591``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1592 \ 1593``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1594 \ 1595``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1596 \ 1597``-virtfs synth,mount_tag=mount_tag`` 1598 Define a new virtual filesystem device and expose it to the guest using 1599 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1600 directory on host is made directly accessible by guest as a pass-through 1601 file system by using the 9P network protocol for communication between 1602 host and guests, if desired even accessible, shared by several guests 1603 simultaniously. 1604 1605 Note that ``-virtfs`` is actually just a convenience shortcut for its 1606 generalized form ``-fsdev -device virtio-9p-pci``. 1607 1608 The general form of pass-through file system options are: 1609 1610 ``local`` 1611 Accesses to the filesystem are done by QEMU. 1612 1613 ``proxy`` 1614 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1615 1616 ``synth`` 1617 Synthetic filesystem, only used by QTests. 1618 1619 ``id=id`` 1620 Specifies identifier for the filesystem device 1621 1622 ``path=path`` 1623 Specifies the export path for the file system device. Files 1624 under this path will be available to the 9p client on the guest. 1625 1626 ``security_model=security_model`` 1627 Specifies the security model to be used for this export path. 1628 Supported security models are "passthrough", "mapped-xattr", 1629 "mapped-file" and "none". In "passthrough" security model, files 1630 are stored using the same credentials as they are created on the 1631 guest. This requires QEMU to run as root. In "mapped-xattr" 1632 security model, some of the file attributes like uid, gid, mode 1633 bits and link target are stored as file attributes. For 1634 "mapped-file" these attributes are stored in the hidden 1635 .virtfs\_metadata directory. Directories exported by this 1636 security model cannot interact with other unix tools. "none" 1637 security model is same as passthrough except the sever won't 1638 report failures if it fails to set file attributes like 1639 ownership. Security model is mandatory only for local fsdriver. 1640 Other fsdrivers (like proxy) don't take security model as a 1641 parameter. 1642 1643 ``writeout=writeout`` 1644 This is an optional argument. The only supported value is 1645 "immediate". This means that host page cache will be used to 1646 read and write data but write notification will be sent to the 1647 guest only when the data has been reported as written by the 1648 storage subsystem. 1649 1650 ``readonly=on`` 1651 Enables exporting 9p share as a readonly mount for guests. By 1652 default read-write access is given. 1653 1654 ``socket=socket`` 1655 Enables proxy filesystem driver to use passed socket file for 1656 communicating with virtfs-proxy-helper(1). Usually a helper like 1657 libvirt will create socketpair and pass one of the fds as 1658 sock\_fd. 1659 1660 ``sock_fd`` 1661 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1662 socket descriptor for interfacing with virtfs-proxy-helper(1). 1663 1664 ``fmode=fmode`` 1665 Specifies the default mode for newly created files on the host. 1666 Works only with security models "mapped-xattr" and 1667 "mapped-file". 1668 1669 ``dmode=dmode`` 1670 Specifies the default mode for newly created directories on the 1671 host. Works only with security models "mapped-xattr" and 1672 "mapped-file". 1673 1674 ``mount_tag=mount_tag`` 1675 Specifies the tag name to be used by the guest to mount this 1676 export point. 1677 1678 ``multidevs=multidevs`` 1679 Specifies how to deal with multiple devices being shared with a 1680 9p export. Supported behaviours are either "remap", "forbid" or 1681 "warn". The latter is the default behaviour on which virtfs 9p 1682 expects only one device to be shared with the same export, and 1683 if more than one device is shared and accessed via the same 9p 1684 export then only a warning message is logged (once) by qemu on 1685 host side. In order to avoid file ID collisions on guest you 1686 should either create a separate virtfs export for each device to 1687 be shared with guests (recommended way) or you might use "remap" 1688 instead which allows you to share multiple devices with only one 1689 export instead, which is achieved by remapping the original 1690 inode numbers from host to guest in a way that would prevent 1691 such collisions. Remapping inodes in such use cases is required 1692 because the original device IDs from host are never passed and 1693 exposed on guest. Instead all files of an export shared with 1694 virtfs always share the same device id on guest. So two files 1695 with identical inode numbers but from actually different devices 1696 on host would otherwise cause a file ID collision and hence 1697 potential misbehaviours on guest. "forbid" on the other hand 1698 assumes like "warn" that only one device is shared by the same 1699 export, however it will not only log a warning message but also 1700 deny access to additional devices on guest. Note though that 1701 "forbid" does currently not block all possible file access 1702 operations (e.g. readdir() would still return entries from other 1703 devices). 1704ERST 1705 1706DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1707 "-iscsi [user=user][,password=password]\n" 1708 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1709 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1710 " [,timeout=timeout]\n" 1711 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1712 1713SRST 1714``-iscsi`` 1715 Configure iSCSI session parameters. 1716ERST 1717 1718DEFHEADING() 1719 1720DEFHEADING(USB convenience options:) 1721 1722DEF("usb", 0, QEMU_OPTION_usb, 1723 "-usb enable on-board USB host controller (if not enabled by default)\n", 1724 QEMU_ARCH_ALL) 1725SRST 1726``-usb`` 1727 Enable USB emulation on machine types with an on-board USB host 1728 controller (if not enabled by default). Note that on-board USB host 1729 controllers may not support USB 3.0. In this case 1730 ``-device qemu-xhci`` can be used instead on machines with PCI. 1731ERST 1732 1733DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1734 "-usbdevice name add the host or guest USB device 'name'\n", 1735 QEMU_ARCH_ALL) 1736SRST 1737``-usbdevice devname`` 1738 Add the USB device devname, and enable an on-board USB controller 1739 if possible and necessary (just like it can be done via 1740 ``-machine usb=on``). Note that this option is mainly intended for 1741 the user's convenience only. More fine-grained control can be 1742 achieved by selecting a USB host controller (if necessary) and the 1743 desired USB device via the ``-device`` option instead. For example, 1744 instead of using ``-usbdevice mouse`` it is possible to use 1745 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1746 to a USB 3.0 controller instead (at least on machines that support 1747 PCI and do not have an USB controller enabled by default yet). 1748 For more details, see the chapter about 1749 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1750 Possible devices for devname are: 1751 1752 ``braille`` 1753 Braille device. This will use BrlAPI to display the braille 1754 output on a real or fake device (i.e. it also creates a 1755 corresponding ``braille`` chardev automatically beside the 1756 ``usb-braille`` USB device). 1757 1758 ``keyboard`` 1759 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1760 1761 ``mouse`` 1762 Virtual Mouse. This will override the PS/2 mouse emulation when 1763 activated. 1764 1765 ``tablet`` 1766 Pointer device that uses absolute coordinates (like a 1767 touchscreen). This means QEMU is able to report the mouse 1768 position without having to grab the mouse. Also overrides the 1769 PS/2 mouse emulation when activated. 1770 1771 ``wacom-tablet`` 1772 Wacom PenPartner USB tablet. 1773 1774 1775ERST 1776 1777DEFHEADING() 1778 1779DEFHEADING(Display options:) 1780 1781DEF("display", HAS_ARG, QEMU_OPTION_display, 1782#if defined(CONFIG_SPICE) 1783 "-display spice-app[,gl=on|off]\n" 1784#endif 1785#if defined(CONFIG_SDL) 1786 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n" 1787 " [,window_close=on|off][,gl=on|core|es|off]\n" 1788#endif 1789#if defined(CONFIG_GTK) 1790 "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n" 1791#endif 1792#if defined(CONFIG_VNC) 1793 "-display vnc=<display>[,<optargs>]\n" 1794#endif 1795#if defined(CONFIG_CURSES) 1796 "-display curses[,charset=<encoding>]\n" 1797#endif 1798#if defined(CONFIG_OPENGL) 1799 "-display egl-headless[,rendernode=<file>]\n" 1800#endif 1801 "-display none\n" 1802 " select display backend type\n" 1803 " The default display is equivalent to\n " 1804#if defined(CONFIG_GTK) 1805 "\"-display gtk\"\n" 1806#elif defined(CONFIG_SDL) 1807 "\"-display sdl\"\n" 1808#elif defined(CONFIG_COCOA) 1809 "\"-display cocoa\"\n" 1810#elif defined(CONFIG_VNC) 1811 "\"-vnc localhost:0,to=99,id=default\"\n" 1812#else 1813 "\"-display none\"\n" 1814#endif 1815 , QEMU_ARCH_ALL) 1816SRST 1817``-display type`` 1818 Select type of display to use. This option is a replacement for the 1819 old style -sdl/-curses/... options. Use ``-display help`` to list 1820 the available display types. Valid values for type are 1821 1822 ``sdl`` 1823 Display video output via SDL (usually in a separate graphics 1824 window; see the SDL documentation for other possibilities). 1825 1826 ``curses`` 1827 Display video output via curses. For graphics device models 1828 which support a text mode, QEMU can display this output using a 1829 curses/ncurses interface. Nothing is displayed when the graphics 1830 device is in graphical mode or if the graphics device does not 1831 support a text mode. Generally only the VGA device models 1832 support text mode. The font charset used by the guest can be 1833 specified with the ``charset`` option, for example 1834 ``charset=CP850`` for IBM CP850 encoding. The default is 1835 ``CP437``. 1836 1837 ``none`` 1838 Do not display video output. The guest will still see an 1839 emulated graphics card, but its output will not be displayed to 1840 the QEMU user. This option differs from the -nographic option in 1841 that it only affects what is done with video output; -nographic 1842 also changes the destination of the serial and parallel port 1843 data. 1844 1845 ``gtk`` 1846 Display video output in a GTK window. This interface provides 1847 drop-down menus and other UI elements to configure and control 1848 the VM during runtime. 1849 1850 ``vnc`` 1851 Start a VNC server on display <arg> 1852 1853 ``egl-headless`` 1854 Offload all OpenGL operations to a local DRI device. For any 1855 graphical display, this display needs to be paired with either 1856 VNC or SPICE displays. 1857 1858 ``spice-app`` 1859 Start QEMU as a Spice server and launch the default Spice client 1860 application. The Spice server will redirect the serial consoles 1861 and QEMU monitors. (Since 4.0) 1862ERST 1863 1864DEF("nographic", 0, QEMU_OPTION_nographic, 1865 "-nographic disable graphical output and redirect serial I/Os to console\n", 1866 QEMU_ARCH_ALL) 1867SRST 1868``-nographic`` 1869 Normally, if QEMU is compiled with graphical window support, it 1870 displays output such as guest graphics, guest console, and the QEMU 1871 monitor in a window. With this option, you can totally disable 1872 graphical output so that QEMU is a simple command line application. 1873 The emulated serial port is redirected on the console and muxed with 1874 the monitor (unless redirected elsewhere explicitly). Therefore, you 1875 can still use QEMU to debug a Linux kernel with a serial console. 1876 Use C-a h for help on switching between the console and monitor. 1877ERST 1878 1879DEF("curses", 0, QEMU_OPTION_curses, 1880 "-curses shorthand for -display curses\n", 1881 QEMU_ARCH_ALL) 1882SRST 1883``-curses`` 1884 Normally, if QEMU is compiled with graphical window support, it 1885 displays output such as guest graphics, guest console, and the QEMU 1886 monitor in a window. With this option, QEMU can display the VGA 1887 output when in text mode using a curses/ncurses interface. Nothing 1888 is displayed in graphical mode. 1889ERST 1890 1891DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1892 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1893 QEMU_ARCH_ALL) 1894SRST 1895``-alt-grab`` 1896 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1897 this also affects the special keys (for fullscreen, monitor-mode 1898 switching, etc). 1899ERST 1900 1901DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1902 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1903 QEMU_ARCH_ALL) 1904SRST 1905``-ctrl-grab`` 1906 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1907 also affects the special keys (for fullscreen, monitor-mode 1908 switching, etc). 1909ERST 1910 1911DEF("no-quit", 0, QEMU_OPTION_no_quit, 1912 "-no-quit disable SDL window close capability\n", QEMU_ARCH_ALL) 1913SRST 1914``-no-quit`` 1915 Disable SDL window close capability. 1916ERST 1917 1918DEF("sdl", 0, QEMU_OPTION_sdl, 1919 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1920SRST 1921``-sdl`` 1922 Enable SDL. 1923ERST 1924 1925DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1926 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1927 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1928 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1929 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1930 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1931 " [,tls-ciphers=<list>]\n" 1932 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1933 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1934 " [,sasl=on|off][,disable-ticketing=on|off]\n" 1935 " [,password=<string>][,password-secret=<secret-id>]\n" 1936 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1937 " [,jpeg-wan-compression=[auto|never|always]]\n" 1938 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1939 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1940 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1941 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1942 " [,gl=[on|off]][,rendernode=<file>]\n" 1943 " enable spice\n" 1944 " at least one of {port, tls-port} is mandatory\n", 1945 QEMU_ARCH_ALL) 1946SRST 1947``-spice option[,option[,...]]`` 1948 Enable the spice remote desktop protocol. Valid options are 1949 1950 ``port=<nr>`` 1951 Set the TCP port spice is listening on for plaintext channels. 1952 1953 ``addr=<addr>`` 1954 Set the IP address spice is listening on. Default is any 1955 address. 1956 1957 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1958 Force using the specified IP version. 1959 1960 ``password=<string>`` 1961 Set the password you need to authenticate. 1962 1963 This option is deprecated and insecure because it leaves the 1964 password visible in the process listing. Use ``password-secret`` 1965 instead. 1966 1967 ``password-secret=<secret-id>`` 1968 Set the ID of the ``secret`` object containing the password 1969 you need to authenticate. 1970 1971 ``sasl=on|off`` 1972 Require that the client use SASL to authenticate with the spice. 1973 The exact choice of authentication method used is controlled 1974 from the system / user's SASL configuration file for the 'qemu' 1975 service. This is typically found in /etc/sasl2/qemu.conf. If 1976 running QEMU as an unprivileged user, an environment variable 1977 SASL\_CONF\_PATH can be used to make it search alternate 1978 locations for the service config. While some SASL auth methods 1979 can also provide data encryption (eg GSSAPI), it is recommended 1980 that SASL always be combined with the 'tls' and 'x509' settings 1981 to enable use of SSL and server certificates. This ensures a 1982 data encryption preventing compromise of authentication 1983 credentials. 1984 1985 ``disable-ticketing=on|off`` 1986 Allow client connects without authentication. 1987 1988 ``disable-copy-paste=on|off`` 1989 Disable copy paste between the client and the guest. 1990 1991 ``disable-agent-file-xfer=on|off`` 1992 Disable spice-vdagent based file-xfer between the client and the 1993 guest. 1994 1995 ``tls-port=<nr>`` 1996 Set the TCP port spice is listening on for encrypted channels. 1997 1998 ``x509-dir=<dir>`` 1999 Set the x509 file directory. Expects same filenames as -vnc 2000 $display,x509=$dir 2001 2002 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2003 The x509 file names can also be configured individually. 2004 2005 ``tls-ciphers=<list>`` 2006 Specify which ciphers to use. 2007 2008 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2009 Force specific channel to be used with or without TLS 2010 encryption. The options can be specified multiple times to 2011 configure multiple channels. The special name "default" can be 2012 used to set the default mode. For channels which are not 2013 explicitly forced into one mode the spice client is allowed to 2014 pick tls/plaintext as he pleases. 2015 2016 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2017 Configure image compression (lossless). Default is auto\_glz. 2018 2019 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2020 Configure wan image compression (lossy for slow links). Default 2021 is auto. 2022 2023 ``streaming-video=[off|all|filter]`` 2024 Configure video stream detection. Default is off. 2025 2026 ``agent-mouse=[on|off]`` 2027 Enable/disable passing mouse events via vdagent. Default is on. 2028 2029 ``playback-compression=[on|off]`` 2030 Enable/disable audio stream compression (using celt 0.5.1). 2031 Default is on. 2032 2033 ``seamless-migration=[on|off]`` 2034 Enable/disable spice seamless migration. Default is off. 2035 2036 ``gl=[on|off]`` 2037 Enable/disable OpenGL context. Default is off. 2038 2039 ``rendernode=<file>`` 2040 DRM render node for OpenGL rendering. If not specified, it will 2041 pick the first available. (Since 2.9) 2042ERST 2043 2044DEF("portrait", 0, QEMU_OPTION_portrait, 2045 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2046 QEMU_ARCH_ALL) 2047SRST 2048``-portrait`` 2049 Rotate graphical output 90 deg left (only PXA LCD). 2050ERST 2051 2052DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2053 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2054 QEMU_ARCH_ALL) 2055SRST 2056``-rotate deg`` 2057 Rotate graphical output some deg left (only PXA LCD). 2058ERST 2059 2060DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2061 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2062 " select video card type\n", QEMU_ARCH_ALL) 2063SRST 2064``-vga type`` 2065 Select type of VGA card to emulate. Valid values for type are 2066 2067 ``cirrus`` 2068 Cirrus Logic GD5446 Video card. All Windows versions starting 2069 from Windows 95 should recognize and use this graphic card. For 2070 optimal performances, use 16 bit color depth in the guest and 2071 the host OS. (This card was the default before QEMU 2.2) 2072 2073 ``std`` 2074 Standard VGA card with Bochs VBE extensions. If your guest OS 2075 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2076 you want to use high resolution modes (>= 1280x1024x16) then you 2077 should use this option. (This card is the default since QEMU 2078 2.2) 2079 2080 ``vmware`` 2081 VMWare SVGA-II compatible adapter. Use it if you have 2082 sufficiently recent XFree86/XOrg server or Windows guest with a 2083 driver for this card. 2084 2085 ``qxl`` 2086 QXL paravirtual graphic card. It is VGA compatible (including 2087 VESA 2.0 VBE support). Works best with qxl guest drivers 2088 installed though. Recommended choice when using the spice 2089 protocol. 2090 2091 ``tcx`` 2092 (sun4m only) Sun TCX framebuffer. This is the default 2093 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2094 colour depths at a fixed resolution of 1024x768. 2095 2096 ``cg3`` 2097 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2098 framebuffer for sun4m machines available in both 1024x768 2099 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2100 wishing to run older Solaris versions. 2101 2102 ``virtio`` 2103 Virtio VGA card. 2104 2105 ``none`` 2106 Disable VGA card. 2107ERST 2108 2109DEF("full-screen", 0, QEMU_OPTION_full_screen, 2110 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2111SRST 2112``-full-screen`` 2113 Start in full screen. 2114ERST 2115 2116DEF("g", HAS_ARG, QEMU_OPTION_g , 2117 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2118 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2119SRST 2120``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2121 Set the initial graphical resolution and depth (PPC, SPARC only). 2122 2123 For PPC the default is 800x600x32. 2124 2125 For SPARC with the TCX graphics device, the default is 1024x768x8 2126 with the option of 1024x768x24. For cgthree, the default is 2127 1024x768x8 with the option of 1152x900x8 for people who wish to use 2128 OBP. 2129ERST 2130 2131DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2132 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2133SRST 2134``-vnc display[,option[,option[,...]]]`` 2135 Normally, if QEMU is compiled with graphical window support, it 2136 displays output such as guest graphics, guest console, and the QEMU 2137 monitor in a window. With this option, you can have QEMU listen on 2138 VNC display display and redirect the VGA display over the VNC 2139 session. It is very useful to enable the usb tablet device when 2140 using this option (option ``-device usb-tablet``). When using the 2141 VNC display, you must use the ``-k`` parameter to set the keyboard 2142 layout if you are not using en-us. Valid syntax for the display is 2143 2144 ``to=L`` 2145 With this option, QEMU will try next available VNC displays, 2146 until the number L, if the origianlly defined "-vnc display" is 2147 not available, e.g. port 5900+display is already used by another 2148 application. By default, to=0. 2149 2150 ``host:d`` 2151 TCP connections will only be allowed from host on display d. By 2152 convention the TCP port is 5900+d. Optionally, host can be 2153 omitted in which case the server will accept connections from 2154 any host. 2155 2156 ``unix:path`` 2157 Connections will be allowed over UNIX domain sockets where path 2158 is the location of a unix socket to listen for connections on. 2159 2160 ``none`` 2161 VNC is initialized but not started. The monitor ``change`` 2162 command can be used to later start the VNC server. 2163 2164 Following the display value there may be one or more option flags 2165 separated by commas. Valid options are 2166 2167 ``reverse=on|off`` 2168 Connect to a listening VNC client via a "reverse" connection. 2169 The client is specified by the display. For reverse network 2170 connections (host:d,``reverse``), the d argument is a TCP port 2171 number, not a display number. 2172 2173 ``websocket=on|off`` 2174 Opens an additional TCP listening port dedicated to VNC 2175 Websocket connections. If a bare websocket option is given, the 2176 Websocket port is 5700+display. An alternative port can be 2177 specified with the syntax ``websocket``\ =port. 2178 2179 If host is specified connections will only be allowed from this 2180 host. It is possible to control the websocket listen address 2181 independently, using the syntax ``websocket``\ =host:port. 2182 2183 If no TLS credentials are provided, the websocket connection 2184 runs in unencrypted mode. If TLS credentials are provided, the 2185 websocket connection requires encrypted client connections. 2186 2187 ``password=on|off`` 2188 Require that password based authentication is used for client 2189 connections. 2190 2191 The password must be set separately using the ``set_password`` 2192 command in the :ref:`QEMU monitor`. The 2193 syntax to change your password is: 2194 ``set_password <protocol> <password>`` where <protocol> could be 2195 either "vnc" or "spice". 2196 2197 If you would like to change <protocol> password expiration, you 2198 should use ``expire_password <protocol> <expiration-time>`` 2199 where expiration time could be one of the following options: 2200 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2201 make password expire in 60 seconds, or 1335196800 to make 2202 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2203 this date and time). 2204 2205 You can also use keywords "now" or "never" for the expiration 2206 time to allow <protocol> password to expire immediately or never 2207 expire. 2208 2209 ``password-secret=<secret-id>`` 2210 Require that password based authentication is used for client 2211 connections, using the password provided by the ``secret`` 2212 object identified by ``secret-id``. 2213 2214 ``tls-creds=ID`` 2215 Provides the ID of a set of TLS credentials to use to secure the 2216 VNC server. They will apply to both the normal VNC server socket 2217 and the websocket socket (if enabled). Setting TLS credentials 2218 will cause the VNC server socket to enable the VeNCrypt auth 2219 mechanism. The credentials should have been previously created 2220 using the ``-object tls-creds`` argument. 2221 2222 ``tls-authz=ID`` 2223 Provides the ID of the QAuthZ authorization object against which 2224 the client's x509 distinguished name will validated. This object 2225 is only resolved at time of use, so can be deleted and recreated 2226 on the fly while the VNC server is active. If missing, it will 2227 default to denying access. 2228 2229 ``sasl=on|off`` 2230 Require that the client use SASL to authenticate with the VNC 2231 server. The exact choice of authentication method used is 2232 controlled from the system / user's SASL configuration file for 2233 the 'qemu' service. This is typically found in 2234 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2235 an environment variable SASL\_CONF\_PATH can be used to make it 2236 search alternate locations for the service config. While some 2237 SASL auth methods can also provide data encryption (eg GSSAPI), 2238 it is recommended that SASL always be combined with the 'tls' 2239 and 'x509' settings to enable use of SSL and server 2240 certificates. This ensures a data encryption preventing 2241 compromise of authentication credentials. See the 2242 :ref:`VNC security` section in the System Emulation Users Guide 2243 for details on using SASL authentication. 2244 2245 ``sasl-authz=ID`` 2246 Provides the ID of the QAuthZ authorization object against which 2247 the client's SASL username will validated. This object is only 2248 resolved at time of use, so can be deleted and recreated on the 2249 fly while the VNC server is active. If missing, it will default 2250 to denying access. 2251 2252 ``acl=on|off`` 2253 Legacy method for enabling authorization of clients against the 2254 x509 distinguished name and SASL username. It results in the 2255 creation of two ``authz-list`` objects with IDs of 2256 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2257 objects must be configured with the HMP ACL commands. 2258 2259 This option is deprecated and should no longer be used. The new 2260 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2261 2262 ``lossy=on|off`` 2263 Enable lossy compression methods (gradient, JPEG, ...). If this 2264 option is set, VNC client may receive lossy framebuffer updates 2265 depending on its encoding settings. Enabling this option can 2266 save a lot of bandwidth at the expense of quality. 2267 2268 ``non-adaptive=on|off`` 2269 Disable adaptive encodings. Adaptive encodings are enabled by 2270 default. An adaptive encoding will try to detect frequently 2271 updated screen regions, and send updates in these regions using 2272 a lossy encoding (like JPEG). This can be really helpful to save 2273 bandwidth when playing videos. Disabling adaptive encodings 2274 restores the original static behavior of encodings like Tight. 2275 2276 ``share=[allow-exclusive|force-shared|ignore]`` 2277 Set display sharing policy. 'allow-exclusive' allows clients to 2278 ask for exclusive access. As suggested by the rfb spec this is 2279 implemented by dropping other connections. Connecting multiple 2280 clients in parallel requires all clients asking for a shared 2281 session (vncviewer: -shared switch). This is the default. 2282 'force-shared' disables exclusive client access. Useful for 2283 shared desktop sessions, where you don't want someone forgetting 2284 specify -shared disconnect everybody else. 'ignore' completely 2285 ignores the shared flag and allows everybody connect 2286 unconditionally. Doesn't conform to the rfb spec but is 2287 traditional QEMU behavior. 2288 2289 ``key-delay-ms`` 2290 Set keyboard delay, for key down and key up events, in 2291 milliseconds. Default is 10. Keyboards are low-bandwidth 2292 devices, so this slowdown can help the device and guest to keep 2293 up and not lose events in case events are arriving in bulk. 2294 Possible causes for the latter are flaky network connections, or 2295 scripts for automated testing. 2296 2297 ``audiodev=audiodev`` 2298 Use the specified audiodev when the VNC client requests audio 2299 transmission. When not using an -audiodev argument, this option 2300 must be omitted, otherwise is must be present and specify a 2301 valid audiodev. 2302 2303 ``power-control=on|off`` 2304 Permit the remote client to issue shutdown, reboot or reset power 2305 control requests. 2306ERST 2307 2308ARCHHEADING(, QEMU_ARCH_I386) 2309 2310ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2311 2312DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2313 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2314 QEMU_ARCH_I386) 2315SRST 2316``-win2k-hack`` 2317 Use it when installing Windows 2000 to avoid a disk full bug. After 2318 Windows 2000 is installed, you no longer need this option (this 2319 option slows down the IDE transfers). 2320ERST 2321 2322DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2323 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2324 QEMU_ARCH_I386) 2325SRST 2326``-no-fd-bootchk`` 2327 Disable boot signature checking for floppy disks in BIOS. May be 2328 needed to boot from old floppy disks. 2329ERST 2330 2331DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2332 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2333SRST 2334``-no-acpi`` 2335 Disable ACPI (Advanced Configuration and Power Interface) support. 2336 Use it if your guest OS complains about ACPI problems (PC target 2337 machine only). 2338ERST 2339 2340DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2341 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2342SRST 2343``-no-hpet`` 2344 Disable HPET support. 2345ERST 2346 2347DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2348 "-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" 2349 " ACPI table description\n", QEMU_ARCH_I386) 2350SRST 2351``-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]...]`` 2352 Add ACPI table with specified header fields and context from 2353 specified files. For file=, take whole ACPI table from the specified 2354 files, including all ACPI headers (possible overridden by other 2355 options). For data=, only data portion of the table is used, all 2356 header information is specified in the command line. If a SLIC table 2357 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2358 fields will override the same in the RSDT and the FADT (a.k.a. 2359 FACP), in order to ensure the field matches required by the 2360 Microsoft SLIC spec and the ACPI spec. 2361ERST 2362 2363DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2364 "-smbios file=binary\n" 2365 " load SMBIOS entry from binary file\n" 2366 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2367 " [,uefi=on|off]\n" 2368 " specify SMBIOS type 0 fields\n" 2369 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2370 " [,uuid=uuid][,sku=str][,family=str]\n" 2371 " specify SMBIOS type 1 fields\n" 2372 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2373 " [,asset=str][,location=str]\n" 2374 " specify SMBIOS type 2 fields\n" 2375 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2376 " [,sku=str]\n" 2377 " specify SMBIOS type 3 fields\n" 2378 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2379 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2380 " specify SMBIOS type 4 fields\n" 2381 "-smbios type=11[,value=str][,path=filename]\n" 2382 " specify SMBIOS type 11 fields\n" 2383 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2384 " [,asset=str][,part=str][,speed=%d]\n" 2385 " specify SMBIOS type 17 fields\n" 2386 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2387 " specify SMBIOS type 41 fields\n", 2388 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2389SRST 2390``-smbios file=binary`` 2391 Load SMBIOS entry from binary file. 2392 2393``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2394 Specify SMBIOS type 0 fields 2395 2396``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2397 Specify SMBIOS type 1 fields 2398 2399``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2400 Specify SMBIOS type 2 fields 2401 2402``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2403 Specify SMBIOS type 3 fields 2404 2405``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2406 Specify SMBIOS type 4 fields 2407 2408``-smbios type=11[,value=str][,path=filename]`` 2409 Specify SMBIOS type 11 fields 2410 2411 This argument can be repeated multiple times, and values are added in the order they are parsed. 2412 Applications intending to use OEM strings data are encouraged to use their application name as 2413 a prefix for the value string. This facilitates passing information for multiple applications 2414 concurrently. 2415 2416 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2417 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2418 2419 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2420 the SMBIOS table in the order in which they appear. 2421 2422 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2423 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2424 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2425 data set, for example, by specifying the serial ID of a block device. 2426 2427 An example passing three strings is 2428 2429 .. parsed-literal:: 2430 2431 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2432 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2433 path=/some/file/with/oemstringsdata.txt 2434 2435 In the guest OS this is visible with the ``dmidecode`` command 2436 2437 .. parsed-literal:: 2438 2439 $ dmidecode -t 11 2440 Handle 0x0E00, DMI type 11, 5 bytes 2441 OEM Strings 2442 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2443 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2444 String 3: myapp:some extra data 2445 2446 2447``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2448 Specify SMBIOS type 17 fields 2449 2450``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2451 Specify SMBIOS type 41 fields 2452 2453 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2454 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2455 position on the PCI bus. 2456 2457 Here is an example of use: 2458 2459 .. parsed-literal:: 2460 2461 -netdev user,id=internet \\ 2462 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2463 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2464 2465 In the guest OS, the device should then appear as ``eno1``: 2466 2467 ..parsed-literal:: 2468 2469 $ ip -brief l 2470 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2471 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2472 2473 Currently, the PCI device has to be attached to the root bus. 2474 2475ERST 2476 2477DEFHEADING() 2478 2479DEFHEADING(Network options:) 2480 2481DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2482#ifdef CONFIG_SLIRP 2483 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2484 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2485 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2486 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2487 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2488#ifndef _WIN32 2489 "[,smb=dir[,smbserver=addr]]\n" 2490#endif 2491 " configure a user mode network backend with ID 'str',\n" 2492 " its DHCP server and optional services\n" 2493#endif 2494#ifdef _WIN32 2495 "-netdev tap,id=str,ifname=name\n" 2496 " configure a host TAP network backend with ID 'str'\n" 2497#else 2498 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2499 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2500 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2501 " [,poll-us=n]\n" 2502 " configure a host TAP network backend with ID 'str'\n" 2503 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2504 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2505 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2506 " to deconfigure it\n" 2507 " use '[down]script=no' to disable script execution\n" 2508 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2509 " configure it\n" 2510 " use 'fd=h' to connect to an already opened TAP interface\n" 2511 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2512 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2513 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2514 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2515 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2516 " use vhost=on to enable experimental in kernel accelerator\n" 2517 " (only has effect for virtio guests which use MSIX)\n" 2518 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2519 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2520 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2521 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2522 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2523 " spent on busy polling for vhost net\n" 2524 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2525 " configure a host TAP network backend with ID 'str' that is\n" 2526 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2527 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2528#endif 2529#ifdef __linux__ 2530 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2531 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2532 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2533 " [,rxcookie=rxcookie][,offset=offset]\n" 2534 " configure a network backend with ID 'str' connected to\n" 2535 " an Ethernet over L2TPv3 pseudowire.\n" 2536 " Linux kernel 3.3+ as well as most routers can talk\n" 2537 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2538 " VM to a router and even VM to Host. It is a nearly-universal\n" 2539 " standard (RFC3931). Note - this implementation uses static\n" 2540 " pre-configured tunnels (same as the Linux kernel).\n" 2541 " use 'src=' to specify source address\n" 2542 " use 'dst=' to specify destination address\n" 2543 " use 'udp=on' to specify udp encapsulation\n" 2544 " use 'srcport=' to specify source udp port\n" 2545 " use 'dstport=' to specify destination udp port\n" 2546 " use 'ipv6=on' to force v6\n" 2547 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2548 " well as a weak security measure\n" 2549 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2550 " use 'txcookie=0x012345678' to specify a txcookie\n" 2551 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2552 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2553 " use 'pincounter=on' to work around broken counter handling in peer\n" 2554 " use 'offset=X' to add an extra offset between header and data\n" 2555#endif 2556 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2557 " configure a network backend to connect to another network\n" 2558 " using a socket connection\n" 2559 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2560 " configure a network backend to connect to a multicast maddr and port\n" 2561 " use 'localaddr=addr' to specify the host address to send packets from\n" 2562 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2563 " configure a network backend to connect to another network\n" 2564 " using an UDP tunnel\n" 2565#ifdef CONFIG_VDE 2566 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2567 " configure a network backend to connect to port 'n' of a vde switch\n" 2568 " running on host and listening for incoming connections on 'socketpath'.\n" 2569 " Use group 'groupname' and mode 'octalmode' to change default\n" 2570 " ownership and permissions for communication port.\n" 2571#endif 2572#ifdef CONFIG_NETMAP 2573 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2574 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2575 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2576 " netmap device, defaults to '/dev/netmap')\n" 2577#endif 2578#ifdef CONFIG_POSIX 2579 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2580 " configure a vhost-user network, backed by a chardev 'dev'\n" 2581#endif 2582#ifdef __linux__ 2583 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2584 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2585#endif 2586 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2587 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2588DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2589 "-nic [tap|bridge|" 2590#ifdef CONFIG_SLIRP 2591 "user|" 2592#endif 2593#ifdef __linux__ 2594 "l2tpv3|" 2595#endif 2596#ifdef CONFIG_VDE 2597 "vde|" 2598#endif 2599#ifdef CONFIG_NETMAP 2600 "netmap|" 2601#endif 2602#ifdef CONFIG_POSIX 2603 "vhost-user|" 2604#endif 2605 "socket][,option][,...][mac=macaddr]\n" 2606 " initialize an on-board / default host NIC (using MAC address\n" 2607 " macaddr) and connect it to the given host network backend\n" 2608 "-nic none use it alone to have zero network devices (the default is to\n" 2609 " provided a 'user' network connection)\n", 2610 QEMU_ARCH_ALL) 2611DEF("net", HAS_ARG, QEMU_OPTION_net, 2612 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2613 " configure or create an on-board (or machine default) NIC and\n" 2614 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2615 "-net [" 2616#ifdef CONFIG_SLIRP 2617 "user|" 2618#endif 2619 "tap|" 2620 "bridge|" 2621#ifdef CONFIG_VDE 2622 "vde|" 2623#endif 2624#ifdef CONFIG_NETMAP 2625 "netmap|" 2626#endif 2627 "socket][,option][,option][,...]\n" 2628 " old way to initialize a host network interface\n" 2629 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2630SRST 2631``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2632 This option is a shortcut for configuring both the on-board 2633 (default) guest NIC hardware and the host network backend in one go. 2634 The host backend options are the same as with the corresponding 2635 ``-netdev`` options below. The guest NIC model can be set with 2636 ``model=modelname``. Use ``model=help`` to list the available device 2637 types. The hardware MAC address can be set with ``mac=macaddr``. 2638 2639 The following two example do exactly the same, to show how ``-nic`` 2640 can be used to shorten the command line length: 2641 2642 .. parsed-literal:: 2643 2644 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2645 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2646 2647``-nic none`` 2648 Indicate that no network devices should be configured. It is used to 2649 override the default configuration (default NIC with "user" host 2650 network backend) which is activated if no other networking options 2651 are provided. 2652 2653``-netdev user,id=id[,option][,option][,...]`` 2654 Configure user mode host network backend which requires no 2655 administrator privilege to run. Valid options are: 2656 2657 ``id=id`` 2658 Assign symbolic name for use in monitor commands. 2659 2660 ``ipv4=on|off and ipv6=on|off`` 2661 Specify that either IPv4 or IPv6 must be enabled. If neither is 2662 specified both protocols are enabled. 2663 2664 ``net=addr[/mask]`` 2665 Set IP network address the guest will see. Optionally specify 2666 the netmask, either in the form a.b.c.d or as number of valid 2667 top-most bits. Default is 10.0.2.0/24. 2668 2669 ``host=addr`` 2670 Specify the guest-visible address of the host. Default is the 2671 2nd IP in the guest network, i.e. x.x.x.2. 2672 2673 ``ipv6-net=addr[/int]`` 2674 Set IPv6 network address the guest will see (default is 2675 fec0::/64). The network prefix is given in the usual hexadecimal 2676 IPv6 address notation. The prefix size is optional, and is given 2677 as the number of valid top-most bits (default is 64). 2678 2679 ``ipv6-host=addr`` 2680 Specify the guest-visible IPv6 address of the host. Default is 2681 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2682 2683 ``restrict=on|off`` 2684 If this option is enabled, the guest will be isolated, i.e. it 2685 will not be able to contact the host and no guest IP packets 2686 will be routed over the host to the outside. This option does 2687 not affect any explicitly set forwarding rules. 2688 2689 ``hostname=name`` 2690 Specifies the client hostname reported by the built-in DHCP 2691 server. 2692 2693 ``dhcpstart=addr`` 2694 Specify the first of the 16 IPs the built-in DHCP server can 2695 assign. Default is the 15th to 31st IP in the guest network, 2696 i.e. x.x.x.15 to x.x.x.31. 2697 2698 ``dns=addr`` 2699 Specify the guest-visible address of the virtual nameserver. The 2700 address must be different from the host address. Default is the 2701 3rd IP in the guest network, i.e. x.x.x.3. 2702 2703 ``ipv6-dns=addr`` 2704 Specify the guest-visible address of the IPv6 virtual 2705 nameserver. The address must be different from the host address. 2706 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2707 2708 ``dnssearch=domain`` 2709 Provides an entry for the domain-search list sent by the 2710 built-in DHCP server. More than one domain suffix can be 2711 transmitted by specifying this option multiple times. If 2712 supported, this will cause the guest to automatically try to 2713 append the given domain suffix(es) in case a domain name can not 2714 be resolved. 2715 2716 Example: 2717 2718 .. parsed-literal:: 2719 2720 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2721 2722 ``domainname=domain`` 2723 Specifies the client domain name reported by the built-in DHCP 2724 server. 2725 2726 ``tftp=dir`` 2727 When using the user mode network stack, activate a built-in TFTP 2728 server. The files in dir will be exposed as the root of a TFTP 2729 server. The TFTP client on the guest must be configured in 2730 binary mode (use the command ``bin`` of the Unix TFTP client). 2731 2732 ``tftp-server-name=name`` 2733 In BOOTP reply, broadcast name as the "TFTP server name" 2734 (RFC2132 option 66). This can be used to advise the guest to 2735 load boot files or configurations from a different server than 2736 the host address. 2737 2738 ``bootfile=file`` 2739 When using the user mode network stack, broadcast file as the 2740 BOOTP filename. In conjunction with ``tftp``, this can be used 2741 to network boot a guest from a local directory. 2742 2743 Example (using pxelinux): 2744 2745 .. parsed-literal:: 2746 2747 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2748 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2749 2750 ``smb=dir[,smbserver=addr]`` 2751 When using the user mode network stack, activate a built-in SMB 2752 server so that Windows OSes can access to the host files in 2753 ``dir`` transparently. The IP address of the SMB server can be 2754 set to addr. By default the 4th IP in the guest network is used, 2755 i.e. x.x.x.4. 2756 2757 In the guest Windows OS, the line: 2758 2759 :: 2760 2761 10.0.2.4 smbserver 2762 2763 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2764 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2765 NT/2000). 2766 2767 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2768 2769 Note that a SAMBA server must be installed on the host OS. 2770 2771 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2772 Redirect incoming TCP or UDP connections to the host port 2773 hostport to the guest IP address guestaddr on guest port 2774 guestport. If guestaddr is not specified, its value is x.x.x.15 2775 (default first address given by the built-in DHCP server). By 2776 specifying hostaddr, the rule can be bound to a specific host 2777 interface. If no connection type is set, TCP is used. This 2778 option can be given multiple times. 2779 2780 For example, to redirect host X11 connection from screen 1 to 2781 guest screen 0, use the following: 2782 2783 .. parsed-literal:: 2784 2785 # on the host 2786 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2787 # this host xterm should open in the guest X11 server 2788 xterm -display :1 2789 2790 To redirect telnet connections from host port 5555 to telnet 2791 port on the guest, use the following: 2792 2793 .. parsed-literal:: 2794 2795 # on the host 2796 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2797 telnet localhost 5555 2798 2799 Then when you use on the host ``telnet localhost 5555``, you 2800 connect to the guest telnet server. 2801 2802 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2803 Forward guest TCP connections to the IP address server on port 2804 port to the character device dev or to a program executed by 2805 cmd:command which gets spawned for each connection. This option 2806 can be given multiple times. 2807 2808 You can either use a chardev directly and have that one used 2809 throughout QEMU's lifetime, like in the following example: 2810 2811 .. parsed-literal:: 2812 2813 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2814 # the guest accesses it 2815 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2816 2817 Or you can execute a command on every TCP connection established 2818 by the guest, so that QEMU behaves similar to an inetd process 2819 for that virtual server: 2820 2821 .. parsed-literal:: 2822 2823 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2824 # and connect the TCP stream to its stdin/stdout 2825 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2826 2827``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2828 Configure a host TAP network backend with ID id. 2829 2830 Use the network script file to configure it and the network script 2831 dfile to deconfigure it. If name is not provided, the OS 2832 automatically provides one. The default network configure script is 2833 ``/etc/qemu-ifup`` and the default network deconfigure script is 2834 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2835 disable script execution. 2836 2837 If running QEMU as an unprivileged user, use the network helper 2838 to configure the TAP interface and attach it to the bridge. 2839 The default network helper executable is 2840 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2841 ``br0``. 2842 2843 ``fd``\ =h can be used to specify the handle of an already opened 2844 host TAP interface. 2845 2846 Examples: 2847 2848 .. parsed-literal:: 2849 2850 #launch a QEMU instance with the default network script 2851 |qemu_system| linux.img -nic tap 2852 2853 .. parsed-literal:: 2854 2855 #launch a QEMU instance with two NICs, each one connected 2856 #to a TAP device 2857 |qemu_system| linux.img \\ 2858 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2859 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2860 2861 .. parsed-literal:: 2862 2863 #launch a QEMU instance with the default network helper to 2864 #connect a TAP device to bridge br0 2865 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2866 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2867 2868``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2869 Connect a host TAP network interface to a host bridge device. 2870 2871 Use the network helper helper to configure the TAP interface and 2872 attach it to the bridge. The default network helper executable is 2873 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2874 ``br0``. 2875 2876 Examples: 2877 2878 .. parsed-literal:: 2879 2880 #launch a QEMU instance with the default network helper to 2881 #connect a TAP device to bridge br0 2882 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2883 2884 .. parsed-literal:: 2885 2886 #launch a QEMU instance with the default network helper to 2887 #connect a TAP device to bridge qemubr0 2888 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2889 2890``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2891 This host network backend can be used to connect the guest's network 2892 to another QEMU virtual machine using a TCP socket connection. If 2893 ``listen`` is specified, QEMU waits for incoming connections on port 2894 (host is optional). ``connect`` is used to connect to another QEMU 2895 instance using the ``listen`` option. ``fd``\ =h specifies an 2896 already opened TCP socket. 2897 2898 Example: 2899 2900 .. parsed-literal:: 2901 2902 # launch a first QEMU instance 2903 |qemu_system| linux.img \\ 2904 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2905 -netdev socket,id=n1,listen=:1234 2906 # connect the network of this instance to the network of the first instance 2907 |qemu_system| linux.img \\ 2908 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2909 -netdev socket,id=n2,connect=127.0.0.1:1234 2910 2911``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2912 Configure a socket host network backend to share the guest's network 2913 traffic with another QEMU virtual machines using a UDP multicast 2914 socket, effectively making a bus for every QEMU with same multicast 2915 address maddr and port. NOTES: 2916 2917 1. Several QEMU can be running on different hosts and share same bus 2918 (assuming correct multicast setup for these hosts). 2919 2920 2. mcast support is compatible with User Mode Linux (argument 2921 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2922 2923 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2924 2925 Example: 2926 2927 .. parsed-literal:: 2928 2929 # launch one QEMU instance 2930 |qemu_system| linux.img \\ 2931 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2932 -netdev socket,id=n1,mcast=230.0.0.1:1234 2933 # launch another QEMU instance on same "bus" 2934 |qemu_system| linux.img \\ 2935 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2936 -netdev socket,id=n2,mcast=230.0.0.1:1234 2937 # launch yet another QEMU instance on same "bus" 2938 |qemu_system| linux.img \\ 2939 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2940 -netdev socket,id=n3,mcast=230.0.0.1:1234 2941 2942 Example (User Mode Linux compat.): 2943 2944 .. parsed-literal:: 2945 2946 # launch QEMU instance (note mcast address selected is UML's default) 2947 |qemu_system| linux.img \\ 2948 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2949 -netdev socket,id=n1,mcast=239.192.168.1:1102 2950 # launch UML 2951 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2952 2953 Example (send packets from host's 1.2.3.4): 2954 2955 .. parsed-literal:: 2956 2957 |qemu_system| linux.img \\ 2958 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2959 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2960 2961``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 2962 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2963 is a popular protocol to transport Ethernet (and other Layer 2) data 2964 frames between two systems. It is present in routers, firewalls and 2965 the Linux kernel (from version 3.3 onwards). 2966 2967 This transport allows a VM to communicate to another VM, router or 2968 firewall directly. 2969 2970 ``src=srcaddr`` 2971 source address (mandatory) 2972 2973 ``dst=dstaddr`` 2974 destination address (mandatory) 2975 2976 ``udp`` 2977 select udp encapsulation (default is ip). 2978 2979 ``srcport=srcport`` 2980 source udp port. 2981 2982 ``dstport=dstport`` 2983 destination udp port. 2984 2985 ``ipv6`` 2986 force v6, otherwise defaults to v4. 2987 2988 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 2989 Cookies are a weak form of security in the l2tpv3 specification. 2990 Their function is mostly to prevent misconfiguration. By default 2991 they are 32 bit. 2992 2993 ``cookie64`` 2994 Set cookie size to 64 bit instead of the default 32 2995 2996 ``counter=off`` 2997 Force a 'cut-down' L2TPv3 with no counter as in 2998 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 2999 3000 ``pincounter=on`` 3001 Work around broken counter handling in peer. This may also help 3002 on networks which have packet reorder. 3003 3004 ``offset=offset`` 3005 Add an extra offset between header and data 3006 3007 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3008 the bridge br-lan on the remote Linux host 1.2.3.4: 3009 3010 .. parsed-literal:: 3011 3012 # Setup tunnel on linux host using raw ip as encapsulation 3013 # on 1.2.3.4 3014 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3015 encap udp udp_sport 16384 udp_dport 16384 3016 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3017 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3018 ifconfig vmtunnel0 mtu 1500 3019 ifconfig vmtunnel0 up 3020 brctl addif br-lan vmtunnel0 3021 3022 3023 # on 4.3.2.1 3024 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3025 3026 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3027 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3028 3029``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3030 Configure VDE backend to connect to PORT n of a vde switch running 3031 on host and listening for incoming connections on socketpath. Use 3032 GROUP groupname and MODE octalmode to change default ownership and 3033 permissions for communication port. This option is only available if 3034 QEMU has been compiled with vde support enabled. 3035 3036 Example: 3037 3038 .. parsed-literal:: 3039 3040 # launch vde switch 3041 vde_switch -F -sock /tmp/myswitch 3042 # launch QEMU instance 3043 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3044 3045``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3046 Establish a vhost-user netdev, backed by a chardev id. The chardev 3047 should be a unix domain socket backed one. The vhost-user uses a 3048 specifically defined protocol to pass vhost ioctl replacement 3049 messages to an application on the other end of the socket. On 3050 non-MSIX guests, the feature can be forced with vhostforce. Use 3051 'queues=n' to specify the number of queues to be created for 3052 multiqueue vhost-user. 3053 3054 Example: 3055 3056 :: 3057 3058 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3059 -numa node,memdev=mem \ 3060 -chardev socket,id=chr0,path=/path/to/socket \ 3061 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3062 -device virtio-net-pci,netdev=net0 3063 3064``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3065 Establish a vhost-vdpa netdev. 3066 3067 vDPA device is a device that uses a datapath which complies with 3068 the virtio specifications with a vendor specific control path. 3069 vDPA devices can be both physically located on the hardware or 3070 emulated by software. 3071 3072``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3073 Create a hub port on the emulated hub with ID hubid. 3074 3075 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3076 instead of a single netdev. Alternatively, you can also connect the 3077 hubport to another netdev with ID nd by using the ``netdev=nd`` 3078 option. 3079 3080``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3081 Legacy option to configure or create an on-board (or machine 3082 default) Network Interface Card(NIC) and connect it either to the 3083 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3084 If model is omitted, then the default NIC model associated with the 3085 machine type is used. Note that the default NIC model may change in 3086 future QEMU releases, so it is highly recommended to always specify 3087 a model. Optionally, the MAC address can be changed to mac, the 3088 device address set to addr (PCI cards only), and a name can be 3089 assigned for use in monitor commands. Optionally, for PCI cards, you 3090 can specify the number v of MSI-X vectors that the card should have; 3091 this option currently only affects virtio cards; set v = 0 to 3092 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3093 created. QEMU can emulate several different models of network card. 3094 Use ``-net nic,model=help`` for a list of available devices for your 3095 target. 3096 3097``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3098 Configure a host network backend (with the options corresponding to 3099 the same ``-netdev`` option) and connect it to the emulated hub 0 3100 (the default hub). Use name to specify the name of the hub port. 3101ERST 3102 3103DEFHEADING() 3104 3105DEFHEADING(Character device options:) 3106 3107DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3108 "-chardev help\n" 3109 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3110 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3111 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3112 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3113 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3114 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3115 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3116 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3117 " [,logfile=PATH][,logappend=on|off]\n" 3118 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3119 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3120 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3121 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3122 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3123 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3124#ifdef _WIN32 3125 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3126 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3127#else 3128 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3129 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3130#endif 3131#ifdef CONFIG_BRLAPI 3132 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3133#endif 3134#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3135 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3136 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3137 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3138#endif 3139#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3140 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3141 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3142#endif 3143#if defined(CONFIG_SPICE) 3144 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3145 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3146#endif 3147 , QEMU_ARCH_ALL 3148) 3149 3150SRST 3151The general form of a character device option is: 3152 3153``-chardev backend,id=id[,mux=on|off][,options]`` 3154 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3155 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3156 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3157 ``spicevmc``, ``spiceport``. The specific backend will determine the 3158 applicable options. 3159 3160 Use ``-chardev help`` to print all available chardev backend types. 3161 3162 All devices must have an id, which can be any string up to 127 3163 characters long. It is used to uniquely identify this device in 3164 other command line directives. 3165 3166 A character device may be used in multiplexing mode by multiple 3167 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3168 a "1:N" device, and here the "1" end is your specified chardev 3169 backend, and the "N" end is the various parts of QEMU that can talk 3170 to a chardev. If you create a chardev with ``id=myid`` and 3171 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3172 and you can then configure multiple front ends to use that chardev 3173 ID for their input/output. Up to four different front ends can be 3174 connected to a single multiplexed chardev. (Without multiplexing 3175 enabled, a chardev can only be used by a single front end.) For 3176 instance you could use this to allow a single stdio chardev to be 3177 used by two serial ports and the QEMU monitor: 3178 3179 :: 3180 3181 -chardev stdio,mux=on,id=char0 \ 3182 -mon chardev=char0,mode=readline \ 3183 -serial chardev:char0 \ 3184 -serial chardev:char0 3185 3186 You can have more than one multiplexer in a system configuration; 3187 for instance you could have a TCP port multiplexed between UART 0 3188 and UART 1, and stdio multiplexed between the QEMU monitor and a 3189 parallel port: 3190 3191 :: 3192 3193 -chardev stdio,mux=on,id=char0 \ 3194 -mon chardev=char0,mode=readline \ 3195 -parallel chardev:char0 \ 3196 -chardev tcp,...,mux=on,id=char1 \ 3197 -serial chardev:char1 \ 3198 -serial chardev:char1 3199 3200 When you're using a multiplexed character device, some escape 3201 sequences are interpreted in the input. See the chapter about 3202 :ref:`keys in the character backend multiplexer` in the 3203 System Emulation Users Guide for more details. 3204 3205 Note that some other command line options may implicitly create 3206 multiplexed character backends; for instance ``-serial mon:stdio`` 3207 creates a multiplexed stdio backend connected to the serial port and 3208 the QEMU monitor, and ``-nographic`` also multiplexes the console 3209 and the monitor to stdio. 3210 3211 There is currently no support for multiplexing in the other 3212 direction (where a single QEMU front end takes input and output from 3213 multiple chardevs). 3214 3215 Every backend supports the ``logfile`` option, which supplies the 3216 path to a file to record all data transmitted via the backend. The 3217 ``logappend`` option controls whether the log file will be truncated 3218 or appended to when opened. 3219 3220The available backends are: 3221 3222``-chardev null,id=id`` 3223 A void device. This device will not emit any data, and will drop any 3224 data it receives. The null backend does not take any options. 3225 3226``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3227 Create a two-way stream socket, which can be either a TCP or a unix 3228 socket. A unix socket will be created if ``path`` is specified. 3229 Behaviour is undefined if TCP options are specified for a unix 3230 socket. 3231 3232 ``server=on|off`` specifies that the socket shall be a listening socket. 3233 3234 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3235 to connect to a listening socket. 3236 3237 ``telnet=on|off`` specifies that traffic on the socket should interpret 3238 telnet escape sequences. 3239 3240 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3241 communication. 3242 3243 ``reconnect`` sets the timeout for reconnecting on non-server 3244 sockets when the remote end goes away. qemu will delay this many 3245 seconds and then attempt to reconnect. Zero disables reconnecting, 3246 and is the default. 3247 3248 ``tls-creds`` requests enablement of the TLS protocol for 3249 encryption, and specifies the id of the TLS credentials to use for 3250 the handshake. The credentials must be previously created with the 3251 ``-object tls-creds`` argument. 3252 3253 ``tls-auth`` provides the ID of the QAuthZ authorization object 3254 against which the client's x509 distinguished name will be 3255 validated. This object is only resolved at time of use, so can be 3256 deleted and recreated on the fly while the chardev server is active. 3257 If missing, it will default to denying access. 3258 3259 TCP and unix socket options are given below: 3260 3261 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3262 ``host`` for a listening socket specifies the local address to 3263 be bound. For a connecting socket species the remote host to 3264 connect to. ``host`` is optional for listening sockets. If not 3265 specified it defaults to ``0.0.0.0``. 3266 3267 ``port`` for a listening socket specifies the local port to be 3268 bound. For a connecting socket specifies the port on the remote 3269 host to connect to. ``port`` can be given as either a port 3270 number or a service name. ``port`` is required. 3271 3272 ``to`` is only relevant to listening sockets. If it is 3273 specified, and ``port`` cannot be bound, QEMU will attempt to 3274 bind to subsequent ports up to and including ``to`` until it 3275 succeeds. ``to`` must be specified as a port number. 3276 3277 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3278 or IPv6 must be used. If neither is specified the socket may 3279 use either protocol. 3280 3281 ``nodelay=on|off`` disables the Nagle algorithm. 3282 3283 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3284 ``path`` specifies the local path of the unix socket. ``path`` 3285 is required. 3286 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3287 rather than the filesystem. Optional, defaults to false. 3288 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3289 rather than the full sun_path length. Optional, defaults to true. 3290 3291``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3292 Sends all traffic from the guest to a remote host over UDP. 3293 3294 ``host`` specifies the remote host to connect to. If not specified 3295 it defaults to ``localhost``. 3296 3297 ``port`` specifies the port on the remote host to connect to. 3298 ``port`` is required. 3299 3300 ``localaddr`` specifies the local address to bind to. If not 3301 specified it defaults to ``0.0.0.0``. 3302 3303 ``localport`` specifies the local port to bind to. If not specified 3304 any available local port will be used. 3305 3306 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3307 If neither is specified the device may use either protocol. 3308 3309``-chardev msmouse,id=id`` 3310 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3311 does not take any options. 3312 3313``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3314 Connect to a QEMU text console. ``vc`` may optionally be given a 3315 specific size. 3316 3317 ``width`` and ``height`` specify the width and height respectively 3318 of the console, in pixels. 3319 3320 ``cols`` and ``rows`` specify that the console be sized to fit a 3321 text console with the given dimensions. 3322 3323``-chardev ringbuf,id=id[,size=size]`` 3324 Create a ring buffer with fixed size ``size``. size must be a power 3325 of two and defaults to ``64K``. 3326 3327``-chardev file,id=id,path=path`` 3328 Log all traffic received from the guest to a file. 3329 3330 ``path`` specifies the path of the file to be opened. This file will 3331 be created if it does not already exist, and overwritten if it does. 3332 ``path`` is required. 3333 3334``-chardev pipe,id=id,path=path`` 3335 Create a two-way connection to the guest. The behaviour differs 3336 slightly between Windows hosts and other hosts: 3337 3338 On Windows, a single duplex pipe will be created at 3339 ``\\.pipe\path``. 3340 3341 On other hosts, 2 pipes will be created called ``path.in`` and 3342 ``path.out``. Data written to ``path.in`` will be received by the 3343 guest. Data written by the guest can be read from ``path.out``. QEMU 3344 will not create these fifos, and requires them to be present. 3345 3346 ``path`` forms part of the pipe path as described above. ``path`` is 3347 required. 3348 3349``-chardev console,id=id`` 3350 Send traffic from the guest to QEMU's standard output. ``console`` 3351 does not take any options. 3352 3353 ``console`` is only available on Windows hosts. 3354 3355``-chardev serial,id=id,path=path`` 3356 Send traffic from the guest to a serial device on the host. 3357 3358 On Unix hosts serial will actually accept any tty device, not only 3359 serial lines. 3360 3361 ``path`` specifies the name of the serial device to open. 3362 3363``-chardev pty,id=id`` 3364 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3365 does not take any options. 3366 3367 ``pty`` is not available on Windows hosts. 3368 3369``-chardev stdio,id=id[,signal=on|off]`` 3370 Connect to standard input and standard output of the QEMU process. 3371 3372 ``signal`` controls if signals are enabled on the terminal, that 3373 includes exiting QEMU with the key sequence Control-c. This option 3374 is enabled by default, use ``signal=off`` to disable it. 3375 3376``-chardev braille,id=id`` 3377 Connect to a local BrlAPI server. ``braille`` does not take any 3378 options. 3379 3380``-chardev tty,id=id,path=path`` 3381 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3382 and DragonFlyBSD hosts. It is an alias for ``serial``. 3383 3384 ``path`` specifies the path to the tty. ``path`` is required. 3385 3386``-chardev parallel,id=id,path=path`` 3387 \ 3388``-chardev parport,id=id,path=path`` 3389 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3390 hosts. 3391 3392 Connect to a local parallel port. 3393 3394 ``path`` specifies the path to the parallel port device. ``path`` is 3395 required. 3396 3397``-chardev spicevmc,id=id,debug=debug,name=name`` 3398 ``spicevmc`` is only available when spice support is built in. 3399 3400 ``debug`` debug level for spicevmc 3401 3402 ``name`` name of spice channel to connect to 3403 3404 Connect to a spice virtual machine channel, such as vdiport. 3405 3406``-chardev spiceport,id=id,debug=debug,name=name`` 3407 ``spiceport`` is only available when spice support is built in. 3408 3409 ``debug`` debug level for spicevmc 3410 3411 ``name`` name of spice port to connect to 3412 3413 Connect to a spice port, allowing a Spice client to handle the 3414 traffic identified by a name (preferably a fqdn). 3415ERST 3416 3417DEFHEADING() 3418 3419#ifdef CONFIG_TPM 3420DEFHEADING(TPM device options:) 3421 3422DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3423 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3424 " use path to provide path to a character device; default is /dev/tpm0\n" 3425 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3426 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3427 "-tpmdev emulator,id=id,chardev=dev\n" 3428 " configure the TPM device using chardev backend\n", 3429 QEMU_ARCH_ALL) 3430SRST 3431The general form of a TPM device option is: 3432 3433``-tpmdev backend,id=id[,options]`` 3434 The specific backend type will determine the applicable options. The 3435 ``-tpmdev`` option creates the TPM backend and requires a 3436 ``-device`` option that specifies the TPM frontend interface model. 3437 3438 Use ``-tpmdev help`` to print all available TPM backend types. 3439 3440The available backends are: 3441 3442``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3443 (Linux-host only) Enable access to the host's TPM using the 3444 passthrough driver. 3445 3446 ``path`` specifies the path to the host's TPM device, i.e., on a 3447 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3448 default ``/dev/tpm0`` is used. 3449 3450 ``cancel-path`` specifies the path to the host TPM device's sysfs 3451 entry allowing for cancellation of an ongoing TPM command. 3452 ``cancel-path`` is optional and by default QEMU will search for the 3453 sysfs entry to use. 3454 3455 Some notes about using the host's TPM with the passthrough driver: 3456 3457 The TPM device accessed by the passthrough driver must not be used 3458 by any other application on the host. 3459 3460 Since the host's firmware (BIOS/UEFI) has already initialized the 3461 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3462 the TPM again and may therefore not show a TPM-specific menu that 3463 would otherwise allow the user to configure the TPM, e.g., allow the 3464 user to enable/disable or activate/deactivate the TPM. Further, if 3465 TPM ownership is released from within a VM then the host's TPM will 3466 get disabled and deactivated. To enable and activate the TPM again 3467 afterwards, the host has to be rebooted and the user is required to 3468 enter the firmware's menu to enable and activate the TPM. If the TPM 3469 is left disabled and/or deactivated most TPM commands will fail. 3470 3471 To create a passthrough TPM use the following two options: 3472 3473 :: 3474 3475 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3476 3477 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3478 ``tpmdev=tpm0`` in the device option. 3479 3480``-tpmdev emulator,id=id,chardev=dev`` 3481 (Linux-host only) Enable access to a TPM emulator using Unix domain 3482 socket based chardev backend. 3483 3484 ``chardev`` specifies the unique ID of a character device backend 3485 that provides connection to the software TPM server. 3486 3487 To create a TPM emulator backend device with chardev socket backend: 3488 3489 :: 3490 3491 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3492ERST 3493 3494DEFHEADING() 3495 3496#endif 3497 3498DEFHEADING(Linux/Multiboot boot specific:) 3499SRST 3500When using these options, you can use a given Linux or Multiboot kernel 3501without installing it in the disk image. It can be useful for easier 3502testing of various kernels. 3503 3504 3505ERST 3506 3507DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3508 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3509SRST 3510``-kernel bzImage`` 3511 Use bzImage as kernel image. The kernel can be either a Linux kernel 3512 or in multiboot format. 3513ERST 3514 3515DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3516 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3517SRST 3518``-append cmdline`` 3519 Use cmdline as kernel command line 3520ERST 3521 3522DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3523 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3524SRST 3525``-initrd file`` 3526 Use file as initial ram disk. 3527 3528``-initrd "file1 arg=foo,file2"`` 3529 This syntax is only available with multiboot. 3530 3531 Use file1 and file2 as modules and pass arg=foo as parameter to the 3532 first module. 3533ERST 3534 3535DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3536 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3537SRST 3538``-dtb file`` 3539 Use file as a device tree binary (dtb) image and pass it to the 3540 kernel on boot. 3541ERST 3542 3543DEFHEADING() 3544 3545DEFHEADING(Debug/Expert options:) 3546 3547DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3548 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3549 " Policy for handling deprecated management interfaces\n", 3550 QEMU_ARCH_ALL) 3551SRST 3552``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3553 Set policy for handling deprecated management interfaces (experimental): 3554 3555 ``deprecated-input=accept`` (default) 3556 Accept deprecated commands and arguments 3557 ``deprecated-input=reject`` 3558 Reject deprecated commands and arguments 3559 ``deprecated-input=crash`` 3560 Crash on deprecated commands and arguments 3561 ``deprecated-output=accept`` (default) 3562 Emit deprecated command results and events 3563 ``deprecated-output=hide`` 3564 Suppress deprecated command results and events 3565 3566 Limitation: covers only syntactic aspects of QMP. 3567ERST 3568 3569DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3570 "-fw_cfg [name=]<name>,file=<file>\n" 3571 " add named fw_cfg entry with contents from file\n" 3572 "-fw_cfg [name=]<name>,string=<str>\n" 3573 " add named fw_cfg entry with contents from string\n", 3574 QEMU_ARCH_ALL) 3575SRST 3576``-fw_cfg [name=]name,file=file`` 3577 Add named fw\_cfg entry with contents from file file. 3578 3579``-fw_cfg [name=]name,string=str`` 3580 Add named fw\_cfg entry with contents from string str. 3581 3582 The terminating NUL character of the contents of str will not be 3583 included as part of the fw\_cfg item data. To insert contents with 3584 embedded NUL characters, you have to use the file parameter. 3585 3586 The fw\_cfg entries are passed by QEMU through to the guest. 3587 3588 Example: 3589 3590 :: 3591 3592 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3593 3594 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3595 from ./my\_blob.bin. 3596ERST 3597 3598DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3599 "-serial dev redirect the serial port to char device 'dev'\n", 3600 QEMU_ARCH_ALL) 3601SRST 3602``-serial dev`` 3603 Redirect the virtual serial port to host character device dev. The 3604 default device is ``vc`` in graphical mode and ``stdio`` in non 3605 graphical mode. 3606 3607 This option can be used several times to simulate up to 4 serial 3608 ports. 3609 3610 Use ``-serial none`` to disable all serial ports. 3611 3612 Available character devices are: 3613 3614 ``vc[:WxH]`` 3615 Virtual console. Optionally, a width and height can be given in 3616 pixel with 3617 3618 :: 3619 3620 vc:800x600 3621 3622 It is also possible to specify width or height in characters: 3623 3624 :: 3625 3626 vc:80Cx24C 3627 3628 ``pty`` 3629 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3630 3631 ``none`` 3632 No device is allocated. 3633 3634 ``null`` 3635 void device 3636 3637 ``chardev:id`` 3638 Use a named character device defined with the ``-chardev`` 3639 option. 3640 3641 ``/dev/XXX`` 3642 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3643 port parameters are set according to the emulated ones. 3644 3645 ``/dev/parportN`` 3646 [Linux only, parallel port only] Use host parallel port N. 3647 Currently SPP and EPP parallel port features can be used. 3648 3649 ``file:filename`` 3650 Write output to filename. No character can be read. 3651 3652 ``stdio`` 3653 [Unix only] standard input/output 3654 3655 ``pipe:filename`` 3656 name pipe filename 3657 3658 ``COMn`` 3659 [Windows only] Use host serial port n 3660 3661 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3662 This implements UDP Net Console. When remote\_host or src\_ip 3663 are not specified they default to ``0.0.0.0``. When not using a 3664 specified src\_port a random port is automatically chosen. 3665 3666 If you just want a simple readonly console you can use 3667 ``netcat`` or ``nc``, by starting QEMU with: 3668 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3669 QEMU writes something to that port it will appear in the 3670 netconsole session. 3671 3672 If you plan to send characters back via netconsole or you want 3673 to stop and start QEMU a lot of times, you should have QEMU use 3674 the same source port each time by using something like ``-serial 3675 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3676 version of netcat which can listen to a TCP port and send and 3677 receive characters via udp. If you have a patched version of 3678 netcat which activates telnet remote echo and single char 3679 transfer, then you can use the following options to set up a 3680 netcat redirector to allow telnet on port 5555 to access the 3681 QEMU port. 3682 3683 ``QEMU Options:`` 3684 -serial udp::4555@:4556 3685 3686 ``netcat options:`` 3687 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3688 3689 ``telnet options:`` 3690 localhost 5555 3691 3692 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3693 The TCP Net Console has two modes of operation. It can send the 3694 serial I/O to a location or wait for a connection from a 3695 location. By default the TCP Net Console is sent to host at the 3696 port. If you use the ``server=on`` option QEMU will wait for a client 3697 socket application to connect to the port before continuing, 3698 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3699 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3700 option only applies if ``server=no`` is set, if the connection goes 3701 down it will attempt to reconnect at the given interval. If host 3702 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3703 time is accepted. You can use ``telnet=on`` to connect to the 3704 corresponding character device. 3705 3706 ``Example to send tcp console to 192.168.0.2 port 4444`` 3707 -serial tcp:192.168.0.2:4444 3708 3709 ``Example to listen and wait on port 4444 for connection`` 3710 -serial tcp::4444,server=on 3711 3712 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3713 -serial tcp:192.168.0.100:4444,server=on,wait=off 3714 3715 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3716 The telnet protocol is used instead of raw tcp sockets. The 3717 options work the same as if you had specified ``-serial tcp``. 3718 The difference is that the port acts like a telnet server or 3719 client using telnet option negotiation. This will also allow you 3720 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3721 supports sending the break sequence. Typically in unix telnet 3722 you do it with Control-] and then type "send break" followed by 3723 pressing the enter key. 3724 3725 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3726 The WebSocket protocol is used instead of raw tcp socket. The 3727 port acts as a WebSocket server. Client mode is not supported. 3728 3729 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3730 A unix domain socket is used instead of a tcp socket. The option 3731 works the same as if you had specified ``-serial tcp`` except 3732 the unix domain socket path is used for connections. 3733 3734 ``mon:dev_string`` 3735 This is a special option to allow the monitor to be multiplexed 3736 onto another serial port. The monitor is accessed with key 3737 sequence of Control-a and then pressing c. dev\_string should be 3738 any one of the serial devices specified above. An example to 3739 multiplex the monitor onto a telnet server listening on port 3740 4444 would be: 3741 3742 ``-serial mon:telnet::4444,server=on,wait=off`` 3743 3744 When the monitor is multiplexed to stdio in this way, Ctrl+C 3745 will not terminate QEMU any more but will be passed to the guest 3746 instead. 3747 3748 ``braille`` 3749 Braille device. This will use BrlAPI to display the braille 3750 output on a real or fake device. 3751 3752 ``msmouse`` 3753 Three button serial mouse. Configure the guest to use Microsoft 3754 protocol. 3755ERST 3756 3757DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3758 "-parallel dev redirect the parallel port to char device 'dev'\n", 3759 QEMU_ARCH_ALL) 3760SRST 3761``-parallel dev`` 3762 Redirect the virtual parallel port to host device dev (same devices 3763 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3764 to use hardware devices connected on the corresponding host parallel 3765 port. 3766 3767 This option can be used several times to simulate up to 3 parallel 3768 ports. 3769 3770 Use ``-parallel none`` to disable all parallel ports. 3771ERST 3772 3773DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3774 "-monitor dev redirect the monitor to char device 'dev'\n", 3775 QEMU_ARCH_ALL) 3776SRST 3777``-monitor dev`` 3778 Redirect the monitor to host device dev (same devices as the serial 3779 port). The default device is ``vc`` in graphical mode and ``stdio`` 3780 in non graphical mode. Use ``-monitor none`` to disable the default 3781 monitor. 3782ERST 3783DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3784 "-qmp dev like -monitor but opens in 'control' mode\n", 3785 QEMU_ARCH_ALL) 3786SRST 3787``-qmp dev`` 3788 Like -monitor but opens in 'control' mode. 3789ERST 3790DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3791 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3792 QEMU_ARCH_ALL) 3793SRST 3794``-qmp-pretty dev`` 3795 Like -qmp but uses pretty JSON formatting. 3796ERST 3797 3798DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3799 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3800SRST 3801``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3802 Setup monitor on chardev name. ``mode=control`` configures 3803 a QMP monitor (a JSON RPC-style protocol) and it is not the 3804 same as HMP, the human monitor that has a "(qemu)" prompt. 3805 ``pretty`` is only valid when ``mode=control``, 3806 turning on JSON pretty printing to ease 3807 human reading and debugging. 3808ERST 3809 3810DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3811 "-debugcon dev redirect the debug console to char device 'dev'\n", 3812 QEMU_ARCH_ALL) 3813SRST 3814``-debugcon dev`` 3815 Redirect the debug console to host device dev (same devices as the 3816 serial port). The debug console is an I/O port which is typically 3817 port 0xe9; writing to that I/O port sends output to this device. The 3818 default device is ``vc`` in graphical mode and ``stdio`` in non 3819 graphical mode. 3820ERST 3821 3822DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3823 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3824SRST 3825``-pidfile file`` 3826 Store the QEMU process PID in file. It is useful if you launch QEMU 3827 from a script. 3828ERST 3829 3830DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3831 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3832SRST 3833``-singlestep`` 3834 Run the emulation in single step mode. 3835ERST 3836 3837DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3838 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3839 QEMU_ARCH_ALL) 3840SRST 3841``--preconfig`` 3842 Pause QEMU for interactive configuration before the machine is 3843 created, which allows querying and configuring properties that will 3844 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3845 exit the preconfig state and move to the next state (i.e. run guest 3846 if -S isn't used or pause the second time if -S is used). This 3847 option is experimental. 3848ERST 3849 3850DEF("S", 0, QEMU_OPTION_S, \ 3851 "-S freeze CPU at startup (use 'c' to start execution)\n", 3852 QEMU_ARCH_ALL) 3853SRST 3854``-S`` 3855 Do not start CPU at startup (you must type 'c' in the monitor). 3856ERST 3857 3858DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3859 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3860 " run qemu with overcommit hints\n" 3861 " mem-lock=on|off controls memory lock support (default: off)\n" 3862 " cpu-pm=on|off controls cpu power management (default: off)\n", 3863 QEMU_ARCH_ALL) 3864SRST 3865``-overcommit mem-lock=on|off`` 3866 \ 3867``-overcommit cpu-pm=on|off`` 3868 Run qemu with hints about host resource overcommit. The default is 3869 to assume that host overcommits all resources. 3870 3871 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3872 (disabled by default). This works when host memory is not 3873 overcommitted and reduces the worst-case latency for guest. 3874 3875 Guest ability to manage power state of host cpus (increasing latency 3876 for other processes on the same host cpu, but decreasing latency for 3877 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3878 works best when host CPU is not overcommitted. When used, host 3879 estimates of CPU cycle and power utilization will be incorrect, not 3880 taking into account guest idle time. 3881ERST 3882 3883DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3884 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3885 " the guest without waiting for gdb to connect; use -S too\n" 3886 " if you want it to not start execution.)\n", 3887 QEMU_ARCH_ALL) 3888SRST 3889``-gdb dev`` 3890 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3891 in the System Emulation Users Guide). Note that this option does not pause QEMU 3892 execution -- if you want QEMU to not start the guest until you 3893 connect with gdb and issue a ``continue`` command, you will need to 3894 also pass the ``-S`` option to QEMU. 3895 3896 The most usual configuration is to listen on a local TCP socket:: 3897 3898 -gdb tcp::3117 3899 3900 but you can specify other backends; UDP, pseudo TTY, or even stdio 3901 are all reasonable use cases. For example, a stdio connection 3902 allows you to start QEMU from within gdb and establish the 3903 connection via a pipe: 3904 3905 .. parsed-literal:: 3906 3907 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3908ERST 3909 3910DEF("s", 0, QEMU_OPTION_s, \ 3911 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3912 QEMU_ARCH_ALL) 3913SRST 3914``-s`` 3915 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3916 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3917ERST 3918 3919DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3920 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3921 QEMU_ARCH_ALL) 3922SRST 3923``-d item1[,...]`` 3924 Enable logging of specified items. Use '-d help' for a list of log 3925 items. 3926ERST 3927 3928DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3929 "-D logfile output log to logfile (default stderr)\n", 3930 QEMU_ARCH_ALL) 3931SRST 3932``-D logfile`` 3933 Output log in logfile instead of to stderr 3934ERST 3935 3936DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3937 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3938 QEMU_ARCH_ALL) 3939SRST 3940``-dfilter range1[,...]`` 3941 Filter debug output to that relevant to a range of target addresses. 3942 The filter spec can be either start+size, start-size or start..end 3943 where start end and size are the addresses and sizes required. For 3944 example: 3945 3946 :: 3947 3948 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3949 3950 Will dump output for any code in the 0x1000 sized block starting at 3951 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3952 another 0x1000 sized block starting at 0xffffffc00005f000. 3953ERST 3954 3955DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3956 "-seed number seed the pseudo-random number generator\n", 3957 QEMU_ARCH_ALL) 3958SRST 3959``-seed number`` 3960 Force the guest to use a deterministic pseudo-random number 3961 generator, seeded with number. This does not affect crypto routines 3962 within the host. 3963ERST 3964 3965DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3966 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3967 QEMU_ARCH_ALL) 3968SRST 3969``-L path`` 3970 Set the directory for the BIOS, VGA BIOS and keymaps. 3971 3972 To list all the data directories, use ``-L help``. 3973ERST 3974 3975DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3976 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3977SRST 3978``-bios file`` 3979 Set the filename for the BIOS. 3980ERST 3981 3982DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 3983 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 3984SRST 3985``-enable-kvm`` 3986 Enable KVM full virtualization support. This option is only 3987 available if KVM support is enabled when compiling. 3988ERST 3989 3990DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 3991 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 3992DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 3993 "-xen-attach attach to existing xen domain\n" 3994 " libxl will use this when starting QEMU\n", 3995 QEMU_ARCH_ALL) 3996DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 3997 "-xen-domid-restrict restrict set of available xen operations\n" 3998 " to specified domain id. (Does not affect\n" 3999 " xenpv machine type).\n", 4000 QEMU_ARCH_ALL) 4001SRST 4002``-xen-domid id`` 4003 Specify xen guest domain id (XEN only). 4004 4005``-xen-attach`` 4006 Attach to existing xen domain. libxl will use this when starting 4007 QEMU (XEN only). Restrict set of available xen operations to 4008 specified domain id (XEN only). 4009ERST 4010 4011DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4012 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4013SRST 4014``-no-reboot`` 4015 Exit instead of rebooting. 4016ERST 4017 4018DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4019 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4020SRST 4021``-no-shutdown`` 4022 Don't exit QEMU on guest shutdown, but instead only stop the 4023 emulation. This allows for instance switching to monitor to commit 4024 changes to the disk image. 4025ERST 4026 4027DEF("action", HAS_ARG, QEMU_OPTION_action, 4028 "-action reboot=reset|shutdown\n" 4029 " action when guest reboots [default=reset]\n" 4030 "-action shutdown=poweroff|pause\n" 4031 " action when guest shuts down [default=poweroff]\n" 4032 "-action panic=pause|shutdown|none\n" 4033 " action when guest panics [default=shutdown]\n" 4034 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4035 " action when watchdog fires [default=reset]\n", 4036 QEMU_ARCH_ALL) 4037SRST 4038``-action event=action`` 4039 The action parameter serves to modify QEMU's default behavior when 4040 certain guest events occur. It provides a generic method for specifying the 4041 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4042 parameters. 4043 4044 Examples: 4045 4046 ``-action panic=none`` 4047 ``-action reboot=shutdown,shutdown=pause`` 4048 ``-watchdog i6300esb -action watchdog=pause`` 4049 4050ERST 4051 4052DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4053 "-loadvm [tag|id]\n" \ 4054 " start right away with a saved state (loadvm in monitor)\n", 4055 QEMU_ARCH_ALL) 4056SRST 4057``-loadvm file`` 4058 Start right away with a saved state (``loadvm`` in monitor) 4059ERST 4060 4061#ifndef _WIN32 4062DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4063 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4064#endif 4065SRST 4066``-daemonize`` 4067 Daemonize the QEMU process after initialization. QEMU will not 4068 detach from standard IO until it is ready to receive connections on 4069 any of its devices. This option is a useful way for external 4070 programs to launch QEMU without having to cope with initialization 4071 race conditions. 4072ERST 4073 4074DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4075 "-option-rom rom load a file, rom, into the option ROM space\n", 4076 QEMU_ARCH_ALL) 4077SRST 4078``-option-rom file`` 4079 Load the contents of file as an option ROM. This option is useful to 4080 load things like EtherBoot. 4081ERST 4082 4083DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4084 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4085 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4086 QEMU_ARCH_ALL) 4087 4088SRST 4089``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4090 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4091 the current UTC or local time, respectively. ``localtime`` is 4092 required for correct date in MS-DOS or Windows. To start at a 4093 specific point in time, provide datetime in the format 4094 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4095 4096 By default the RTC is driven by the host system time. This allows 4097 using of the RTC as accurate reference clock inside the guest, 4098 specifically if the host time is smoothly following an accurate 4099 external reference clock, e.g. via NTP. If you want to isolate the 4100 guest time from the host, you can set ``clock`` to ``rt`` instead, 4101 which provides a host monotonic clock if host support it. To even 4102 prevent the RTC from progressing during suspension, you can set 4103 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4104 recommended especially in icount mode in order to preserve 4105 determinism; however, note that in icount mode the speed of the 4106 virtual clock is variable and can in general differ from the host 4107 clock. 4108 4109 Enable ``driftfix`` (i386 targets only) if you experience time drift 4110 problems, specifically with Windows' ACPI HAL. This option will try 4111 to figure out how many timer interrupts were not processed by the 4112 Windows guest and will re-inject them. 4113ERST 4114 4115DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4116 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4117 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4118 " instruction, enable aligning the host and virtual clocks\n" \ 4119 " or disable real time cpu sleeping, and optionally enable\n" \ 4120 " record-and-replay mode\n", QEMU_ARCH_ALL) 4121SRST 4122``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4123 Enable virtual instruction counter. The virtual cpu will execute one 4124 instruction every 2^N ns of virtual time. If ``auto`` is specified 4125 then the virtual cpu speed will be automatically adjusted to keep 4126 virtual time within a few seconds of real time. 4127 4128 Note that while this option can give deterministic behavior, it does 4129 not provide cycle accurate emulation. Modern CPUs contain 4130 superscalar out of order cores with complex cache hierarchies. The 4131 number of instructions executed often has little or no correlation 4132 with actual performance. 4133 4134 When the virtual cpu is sleeping, the virtual time will advance at 4135 default speed unless ``sleep=on`` is specified. With 4136 ``sleep=on``, the virtual time will jump to the next timer 4137 deadline instantly whenever the virtual cpu goes to sleep mode and 4138 will not advance if no timer is enabled. This behavior gives 4139 deterministic execution times from the guest point of view. 4140 The default if icount is enabled is ``sleep=off``. 4141 ``sleep=on`` cannot be used together with either ``shift=auto`` 4142 or ``align=on``. 4143 4144 ``align=on`` will activate the delay algorithm which will try to 4145 synchronise the host clock and the virtual clock. The goal is to 4146 have a guest running at the real frequency imposed by the shift 4147 option. Whenever the guest clock is behind the host clock and if 4148 ``align=on`` is specified then we print a message to the user to 4149 inform about the delay. Currently this option does not work when 4150 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4151 shift values for which the guest clock runs ahead of the host clock. 4152 Typically this happens when the shift value is high (how high 4153 depends on the host machine). The default if icount is enabled 4154 is ``align=off``. 4155 4156 When the ``rr`` option is specified deterministic record/replay is 4157 enabled. The ``rrfile=`` option must also be provided to 4158 specify the path to the replay log. In record mode data is written 4159 to this file, and in replay mode it is read back. 4160 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4161 name. In record mode, a new VM snapshot with the given name is created 4162 at the start of execution recording. In replay mode this option 4163 specifies the snapshot name used to load the initial VM state. 4164ERST 4165 4166DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4167 "-watchdog model\n" \ 4168 " enable virtual hardware watchdog [default=none]\n", 4169 QEMU_ARCH_ALL) 4170SRST 4171``-watchdog model`` 4172 Create a virtual hardware watchdog device. Once enabled (by a guest 4173 action), the watchdog must be periodically polled by an agent inside 4174 the guest or else the guest will be restarted. Choose a model for 4175 which your guest has drivers. 4176 4177 The model is the model of hardware watchdog to emulate. Use 4178 ``-watchdog help`` to list available hardware models. Only one 4179 watchdog can be enabled for a guest. 4180 4181 The following models may be available: 4182 4183 ``ib700`` 4184 iBASE 700 is a very simple ISA watchdog with a single timer. 4185 4186 ``i6300esb`` 4187 Intel 6300ESB I/O controller hub is a much more featureful 4188 PCI-based dual-timer watchdog. 4189 4190 ``diag288`` 4191 A virtual watchdog for s390x backed by the diagnose 288 4192 hypercall (currently KVM only). 4193ERST 4194 4195DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4196 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4197 " action when watchdog fires [default=reset]\n", 4198 QEMU_ARCH_ALL) 4199SRST 4200``-watchdog-action action`` 4201 The action controls what QEMU will do when the watchdog timer 4202 expires. The default is ``reset`` (forcefully reset the guest). 4203 Other possible actions are: ``shutdown`` (attempt to gracefully 4204 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4205 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4206 guest), ``debug`` (print a debug message and continue), or ``none`` 4207 (do nothing). 4208 4209 Note that the ``shutdown`` action requires that the guest responds 4210 to ACPI signals, which it may not be able to do in the sort of 4211 situations where the watchdog would have expired, and thus 4212 ``-watchdog-action shutdown`` is not recommended for production use. 4213 4214 Examples: 4215 4216 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4217 4218ERST 4219 4220DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4221 "-echr chr set terminal escape character instead of ctrl-a\n", 4222 QEMU_ARCH_ALL) 4223SRST 4224``-echr numeric_ascii_value`` 4225 Change the escape character used for switching to the monitor when 4226 using monitor and serial sharing. The default is ``0x01`` when using 4227 the ``-nographic`` option. ``0x01`` is equal to pressing 4228 ``Control-a``. You can select a different character from the ascii 4229 control keys where 1 through 26 map to Control-a through Control-z. 4230 For instance you could use the either of the following to change the 4231 escape character to Control-t. 4232 4233 ``-echr 0x14``; \ ``-echr 20`` 4234 4235ERST 4236 4237DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4238 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4239 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4240 "-incoming unix:socketpath\n" \ 4241 " prepare for incoming migration, listen on\n" \ 4242 " specified protocol and socket address\n" \ 4243 "-incoming fd:fd\n" \ 4244 "-incoming exec:cmdline\n" \ 4245 " accept incoming migration on given file descriptor\n" \ 4246 " or from given external command\n" \ 4247 "-incoming defer\n" \ 4248 " wait for the URI to be specified via migrate_incoming\n", 4249 QEMU_ARCH_ALL) 4250SRST 4251``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4252 \ 4253``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4254 Prepare for incoming migration, listen on a given tcp port. 4255 4256``-incoming unix:socketpath`` 4257 Prepare for incoming migration, listen on a given unix socket. 4258 4259``-incoming fd:fd`` 4260 Accept incoming migration from a given filedescriptor. 4261 4262``-incoming exec:cmdline`` 4263 Accept incoming migration as an output from specified external 4264 command. 4265 4266``-incoming defer`` 4267 Wait for the URI to be specified via migrate\_incoming. The monitor 4268 can be used to change settings (such as migration parameters) prior 4269 to issuing the migrate\_incoming to allow the migration to begin. 4270ERST 4271 4272DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4273 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4274SRST 4275``-only-migratable`` 4276 Only allow migratable devices. Devices will not be allowed to enter 4277 an unmigratable state. 4278ERST 4279 4280DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4281 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4282SRST 4283``-nodefaults`` 4284 Don't create default devices. Normally, QEMU sets the default 4285 devices like serial port, parallel port, virtual console, monitor 4286 device, VGA adapter, floppy and CD-ROM drive and others. The 4287 ``-nodefaults`` option will disable all those default devices. 4288ERST 4289 4290#ifndef _WIN32 4291DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4292 "-chroot dir chroot to dir just before starting the VM\n", 4293 QEMU_ARCH_ALL) 4294#endif 4295SRST 4296``-chroot dir`` 4297 Immediately before starting guest execution, chroot to the specified 4298 directory. Especially useful in combination with -runas. 4299ERST 4300 4301#ifndef _WIN32 4302DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4303 "-runas user change to user id user just before starting the VM\n" \ 4304 " user can be numeric uid:gid instead\n", 4305 QEMU_ARCH_ALL) 4306#endif 4307SRST 4308``-runas user`` 4309 Immediately before starting guest execution, drop root privileges, 4310 switching to the specified user. 4311ERST 4312 4313DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4314 "-prom-env variable=value\n" 4315 " set OpenBIOS nvram variables\n", 4316 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4317SRST 4318``-prom-env variable=value`` 4319 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4320 4321 :: 4322 4323 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4324 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4325 4326 :: 4327 4328 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4329 -prom-env 'boot-device=hd:2,\yaboot' \ 4330 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4331ERST 4332DEF("semihosting", 0, QEMU_OPTION_semihosting, 4333 "-semihosting semihosting mode\n", 4334 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4335 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4336SRST 4337``-semihosting`` 4338 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4339 4340 Note that this allows guest direct access to the host filesystem, so 4341 should only be used with a trusted guest OS. 4342 4343 See the -semihosting-config option documentation for further 4344 information about the facilities this enables. 4345ERST 4346DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4347 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4348 " semihosting configuration\n", 4349QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4350QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4351SRST 4352``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4353 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4354 only). 4355 4356 Note that this allows guest direct access to the host filesystem, so 4357 should only be used with a trusted guest OS. 4358 4359 On Arm this implements the standard semihosting API, version 2.0. 4360 4361 On M68K this implements the "ColdFire GDB" interface used by 4362 libgloss. 4363 4364 Xtensa semihosting provides basic file IO calls, such as 4365 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4366 linux platform "sim" use this interface. 4367 4368 On RISC-V this implements the standard semihosting API, version 0.2. 4369 4370 ``target=native|gdb|auto`` 4371 Defines where the semihosting calls will be addressed, to QEMU 4372 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4373 means ``gdb`` during debug sessions and ``native`` otherwise. 4374 4375 ``chardev=str1`` 4376 Send the output to a chardev backend output for native or auto 4377 output when not in gdb 4378 4379 ``arg=str1,arg=str2,...`` 4380 Allows the user to pass input arguments, and can be used 4381 multiple times to build up a list. The old-style 4382 ``-kernel``/``-append`` method of passing a command line is 4383 still supported for backward compatibility. If both the 4384 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4385 specified, the former is passed to semihosting as it always 4386 takes precedence. 4387ERST 4388DEF("old-param", 0, QEMU_OPTION_old_param, 4389 "-old-param old param mode\n", QEMU_ARCH_ARM) 4390SRST 4391``-old-param`` 4392 Old param mode (ARM only). 4393ERST 4394 4395DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4396 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4397 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4398 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4399 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4400 " by the kernel, but typically no longer used by modern\n" \ 4401 " C library implementations.\n" \ 4402 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4403 " to elevate privileges using set*uid|gid system calls.\n" \ 4404 " The value 'children' will deny set*uid|gid system calls for\n" \ 4405 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4406 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4407 " blocking *fork and execve\n" \ 4408 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4409 QEMU_ARCH_ALL) 4410SRST 4411``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4412 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4413 filtering and 'off' will disable it. The default is 'off'. 4414 4415 ``obsolete=string`` 4416 Enable Obsolete system calls 4417 4418 ``elevateprivileges=string`` 4419 Disable set\*uid\|gid system calls 4420 4421 ``spawn=string`` 4422 Disable \*fork and execve 4423 4424 ``resourcecontrol=string`` 4425 Disable process affinity and schedular priority 4426ERST 4427 4428DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4429 "-readconfig <file>\n", QEMU_ARCH_ALL) 4430SRST 4431``-readconfig file`` 4432 Read device configuration from file. This approach is useful when 4433 you want to spawn QEMU process with many command line options but 4434 you don't want to exceed the command line character limit. 4435ERST 4436DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4437 "-writeconfig <file>\n" 4438 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4439SRST 4440ERST 4441 4442DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4443 "-no-user-config\n" 4444 " do not load default user-provided config files at startup\n", 4445 QEMU_ARCH_ALL) 4446SRST 4447``-no-user-config`` 4448 The ``-no-user-config`` option makes QEMU not load any of the 4449 user-provided config files on sysconfdir. 4450ERST 4451 4452DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4453 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4454 " specify tracing options\n", 4455 QEMU_ARCH_ALL) 4456SRST 4457``-trace [[enable=]pattern][,events=file][,file=file]`` 4458 .. include:: ../qemu-option-trace.rst.inc 4459 4460ERST 4461DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4462 "-plugin [file=]<file>[,arg=<string>]\n" 4463 " load a plugin\n", 4464 QEMU_ARCH_ALL) 4465SRST 4466``-plugin file=file[,arg=string]`` 4467 Load a plugin. 4468 4469 ``file=file`` 4470 Load the given plugin from a shared library file. 4471 4472 ``arg=string`` 4473 Argument string passed to the plugin. (Can be given multiple 4474 times.) 4475ERST 4476 4477HXCOMM Internal use 4478DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4479DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4480 4481#ifdef __linux__ 4482DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4483 "-enable-fips enable FIPS 140-2 compliance\n", 4484 QEMU_ARCH_ALL) 4485#endif 4486SRST 4487``-enable-fips`` 4488 Enable FIPS 140-2 compliance mode. 4489ERST 4490 4491DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4492 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4493 " control error message format\n" 4494 " timestamp=on enables timestamps (default: off)\n" 4495 " guest-name=on enables guest name prefix but only if\n" 4496 " -name guest option is set (default: off)\n", 4497 QEMU_ARCH_ALL) 4498SRST 4499``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4500 Control error message format. 4501 4502 ``timestamp=on|off`` 4503 Prefix messages with a timestamp. Default is off. 4504 4505 ``guest-name=on|off`` 4506 Prefix messages with guest name but only if -name guest option is set 4507 otherwise the option is ignored. Default is off. 4508ERST 4509 4510DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4511 "-dump-vmstate <file>\n" 4512 " Output vmstate information in JSON format to file.\n" 4513 " Use the scripts/vmstate-static-checker.py file to\n" 4514 " check for possible regressions in migration code\n" 4515 " by comparing two such vmstate dumps.\n", 4516 QEMU_ARCH_ALL) 4517SRST 4518``-dump-vmstate file`` 4519 Dump json-encoded vmstate information for current machine type to 4520 file in file 4521ERST 4522 4523DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4524 "-enable-sync-profile\n" 4525 " enable synchronization profiling\n", 4526 QEMU_ARCH_ALL) 4527SRST 4528``-enable-sync-profile`` 4529 Enable synchronization profiling. 4530ERST 4531 4532DEFHEADING() 4533 4534DEFHEADING(Generic object creation:) 4535 4536DEF("object", HAS_ARG, QEMU_OPTION_object, 4537 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4538 " create a new object of type TYPENAME setting properties\n" 4539 " in the order they are specified. Note that the 'id'\n" 4540 " property must be set. These objects are placed in the\n" 4541 " '/objects' path.\n", 4542 QEMU_ARCH_ALL) 4543SRST 4544``-object typename[,prop1=value1,...]`` 4545 Create a new object of type typename setting properties in the order 4546 they are specified. Note that the 'id' property must be set. These 4547 objects are placed in the '/objects' path. 4548 4549 ``-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`` 4550 Creates a memory file backend object, which can be used to back 4551 the guest RAM with huge pages. 4552 4553 The ``id`` parameter is a unique ID that will be used to 4554 reference this memory region in other parameters, e.g. ``-numa``, 4555 ``-device nvdimm``, etc. 4556 4557 The ``size`` option provides the size of the memory region, and 4558 accepts common suffixes, e.g. ``500M``. 4559 4560 The ``mem-path`` provides the path to either a shared memory or 4561 huge page filesystem mount. 4562 4563 The ``share`` boolean option determines whether the memory 4564 region is marked as private to QEMU, or shared. The latter 4565 allows a co-operating external process to access the QEMU memory 4566 region. 4567 4568 The ``share`` is also required for pvrdma devices due to 4569 limitations in the RDMA API provided by Linux. 4570 4571 Setting share=on might affect the ability to configure NUMA 4572 bindings for the memory backend under some circumstances, see 4573 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4574 source tree for additional details. 4575 4576 Setting the ``discard-data`` boolean option to on indicates that 4577 file contents can be destroyed when QEMU exits, to avoid 4578 unnecessarily flushing data to the backing file. Note that 4579 ``discard-data`` is only an optimization, and QEMU might not 4580 discard file contents if it aborts unexpectedly or is terminated 4581 using SIGKILL. 4582 4583 The ``merge`` boolean option enables memory merge, also known as 4584 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4585 the pages for memory deduplication. 4586 4587 Setting the ``dump`` boolean option to off excludes the memory 4588 from core dumps. This feature is also known as MADV\_DONTDUMP. 4589 4590 The ``prealloc`` boolean option enables memory preallocation. 4591 4592 The ``host-nodes`` option binds the memory range to a list of 4593 NUMA host nodes. 4594 4595 The ``policy`` option sets the NUMA policy to one of the 4596 following values: 4597 4598 ``default`` 4599 default host policy 4600 4601 ``preferred`` 4602 prefer the given host node list for allocation 4603 4604 ``bind`` 4605 restrict memory allocation to the given host node list 4606 4607 ``interleave`` 4608 interleave memory allocations across the given host node 4609 list 4610 4611 The ``align`` option specifies the base address alignment when 4612 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4613 ``2M``. Some backend store specified by ``mem-path`` requires an 4614 alignment different than the default one used by QEMU, eg the 4615 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4616 such cases, users can specify the required alignment via this 4617 option. 4618 4619 The ``pmem`` option specifies whether the backing file specified 4620 by ``mem-path`` is in host persistent memory that can be 4621 accessed using the SNIA NVM programming model (e.g. Intel 4622 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4623 operations to guarantee the persistence of its own writes to 4624 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4625 migration). Also, we will map the backend-file with MAP\_SYNC 4626 flag, which ensures the file metadata is in sync for 4627 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4628 requires support from both the host kernel (since Linux kernel 4629 4.15) and the filesystem of ``mem-path`` mounted with DAX 4630 option. 4631 4632 The ``readonly`` option specifies whether the backing file is opened 4633 read-only or read-write (default). 4634 4635 ``-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`` 4636 Creates a memory backend object, which can be used to back the 4637 guest RAM. Memory backend objects offer more control than the 4638 ``-m`` option that is traditionally used to define guest RAM. 4639 Please refer to ``memory-backend-file`` for a description of the 4640 options. 4641 4642 ``-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`` 4643 Creates an anonymous memory file backend object, which allows 4644 QEMU to share the memory with an external process (e.g. when 4645 using vhost-user). The memory is allocated with memfd and 4646 optional sealing. (Linux only) 4647 4648 The ``seal`` option creates a sealed-file, that will block 4649 further resizing the memory ('on' by default). 4650 4651 The ``hugetlb`` option specify the file to be created resides in 4652 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4653 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4654 the hugetlb page size on systems that support multiple hugetlb 4655 page sizes (it must be a power of 2 value supported by the 4656 system). 4657 4658 In some versions of Linux, the ``hugetlb`` option is 4659 incompatible with the ``seal`` option (requires at least Linux 4660 4.16). 4661 4662 Please refer to ``memory-backend-file`` for a description of the 4663 other options. 4664 4665 The ``share`` boolean option is on by default with memfd. 4666 4667 ``-object rng-builtin,id=id`` 4668 Creates a random number generator backend which obtains entropy 4669 from QEMU builtin functions. The ``id`` parameter is a unique ID 4670 that will be used to reference this entropy backend from the 4671 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4672 uses this RNG backend. 4673 4674 ``-object rng-random,id=id,filename=/dev/random`` 4675 Creates a random number generator backend which obtains entropy 4676 from a device on the host. The ``id`` parameter is a unique ID 4677 that will be used to reference this entropy backend from the 4678 ``virtio-rng`` device. The ``filename`` parameter specifies 4679 which file to obtain entropy from and if omitted defaults to 4680 ``/dev/urandom``. 4681 4682 ``-object rng-egd,id=id,chardev=chardevid`` 4683 Creates a random number generator backend which obtains entropy 4684 from an external daemon running on the host. The ``id`` 4685 parameter is a unique ID that will be used to reference this 4686 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4687 parameter is the unique ID of a character device backend that 4688 provides the connection to the RNG daemon. 4689 4690 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4691 Creates a TLS anonymous credentials object, which can be used to 4692 provide TLS support on network backends. The ``id`` parameter is 4693 a unique ID which network backends will use to access the 4694 credentials. The ``endpoint`` is either ``server`` or ``client`` 4695 depending on whether the QEMU network backend that uses the 4696 credentials will be acting as a client or as a server. If 4697 ``verify-peer`` is enabled (the default) then once the handshake 4698 is completed, the peer credentials will be verified, though this 4699 is a no-op for anonymous credentials. 4700 4701 The dir parameter tells QEMU where to find the credential files. 4702 For server endpoints, this directory may contain a file 4703 dh-params.pem providing diffie-hellman parameters to use for the 4704 TLS server. If the file is missing, QEMU will generate a set of 4705 DH parameters at startup. This is a computationally expensive 4706 operation that consumes random pool entropy, so it is 4707 recommended that a persistent set of parameters be generated 4708 upfront and saved. 4709 4710 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4711 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4712 can be used to provide TLS support on network backends. The 4713 ``id`` parameter is a unique ID which network backends will use 4714 to access the credentials. The ``endpoint`` is either ``server`` 4715 or ``client`` depending on whether the QEMU network backend that 4716 uses the credentials will be acting as a client or as a server. 4717 For clients only, ``username`` is the username which will be 4718 sent to the server. If omitted it defaults to "qemu". 4719 4720 The dir parameter tells QEMU where to find the keys file. It is 4721 called "dir/keys.psk" and contains "username:key" pairs. This 4722 file can most easily be created using the GnuTLS ``psktool`` 4723 program. 4724 4725 For server endpoints, dir may also contain a file dh-params.pem 4726 providing diffie-hellman parameters to use for the TLS server. 4727 If the file is missing, QEMU will generate a set of DH 4728 parameters at startup. This is a computationally expensive 4729 operation that consumes random pool entropy, so it is 4730 recommended that a persistent set of parameters be generated up 4731 front and saved. 4732 4733 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4734 Creates a TLS anonymous credentials object, which can be used to 4735 provide TLS support on network backends. The ``id`` parameter is 4736 a unique ID which network backends will use to access the 4737 credentials. The ``endpoint`` is either ``server`` or ``client`` 4738 depending on whether the QEMU network backend that uses the 4739 credentials will be acting as a client or as a server. If 4740 ``verify-peer`` is enabled (the default) then once the handshake 4741 is completed, the peer credentials will be verified. With x509 4742 certificates, this implies that the clients must be provided 4743 with valid client certificates too. 4744 4745 The dir parameter tells QEMU where to find the credential files. 4746 For server endpoints, this directory may contain a file 4747 dh-params.pem providing diffie-hellman parameters to use for the 4748 TLS server. If the file is missing, QEMU will generate a set of 4749 DH parameters at startup. This is a computationally expensive 4750 operation that consumes random pool entropy, so it is 4751 recommended that a persistent set of parameters be generated 4752 upfront and saved. 4753 4754 For x509 certificate credentials the directory will contain 4755 further files providing the x509 certificates. The certificates 4756 must be stored in PEM format, in filenames ca-cert.pem, 4757 ca-crl.pem (optional), server-cert.pem (only servers), 4758 server-key.pem (only servers), client-cert.pem (only clients), 4759 and client-key.pem (only clients). 4760 4761 For the server-key.pem and client-key.pem files which contain 4762 sensitive private keys, it is possible to use an encrypted 4763 version by providing the passwordid parameter. This provides the 4764 ID of a previously created ``secret`` object containing the 4765 password for decryption. 4766 4767 The priority parameter allows to override the global default 4768 priority used by gnutls. This can be useful if the system 4769 administrator needs to use a weaker set of crypto priorities for 4770 QEMU without potentially forcing the weakness onto all 4771 applications. Or conversely if one wants wants a stronger 4772 default for QEMU than for all other applications, they can do 4773 this through this parameter. Its format is a gnutls priority 4774 string as described at 4775 https://gnutls.org/manual/html_node/Priority-Strings.html. 4776 4777 ``-object tls-cipher-suites,id=id,priority=priority`` 4778 Creates a TLS cipher suites object, which can be used to control 4779 the TLS cipher/protocol algorithms that applications are permitted 4780 to use. 4781 4782 The ``id`` parameter is a unique ID which frontends will use to 4783 access the ordered list of permitted TLS cipher suites from the 4784 host. 4785 4786 The ``priority`` parameter allows to override the global default 4787 priority used by gnutls. This can be useful if the system 4788 administrator needs to use a weaker set of crypto priorities for 4789 QEMU without potentially forcing the weakness onto all 4790 applications. Or conversely if one wants wants a stronger 4791 default for QEMU than for all other applications, they can do 4792 this through this parameter. Its format is a gnutls priority 4793 string as described at 4794 https://gnutls.org/manual/html_node/Priority-Strings.html. 4795 4796 An example of use of this object is to control UEFI HTTPS Boot. 4797 The tls-cipher-suites object exposes the ordered list of permitted 4798 TLS cipher suites from the host side to the guest firmware, via 4799 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4800 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4801 guest-side TLS. 4802 4803 In the following example, the priority at which the host-side policy 4804 is retrieved is given by the ``priority`` property. 4805 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4806 refer to /etc/crypto-policies/back-ends/gnutls.config. 4807 4808 .. parsed-literal:: 4809 4810 # |qemu_system| \\ 4811 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4812 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4813 4814 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4815 Interval t can't be 0, this filter batches the packet delivery: 4816 all packets arriving in a given interval on netdev netdevid are 4817 delayed until the end of the interval. Interval is in 4818 microseconds. ``status`` is optional that indicate whether the 4819 netfilter is on (enabled) or off (disabled), the default status 4820 for netfilter will be 'on'. 4821 4822 queue all\|rx\|tx is an option that can be applied to any 4823 netfilter. 4824 4825 ``all``: the filter is attached both to the receive and the 4826 transmit queue of the netdev (default). 4827 4828 ``rx``: the filter is attached to the receive queue of the 4829 netdev, where it will receive packets sent to the netdev. 4830 4831 ``tx``: the filter is attached to the transmit queue of the 4832 netdev, where it will receive packets sent by the netdev. 4833 4834 position head\|tail\|id=<id> is an option to specify where the 4835 filter should be inserted in the filter list. It can be applied 4836 to any netfilter. 4837 4838 ``head``: the filter is inserted at the head of the filter list, 4839 before any existing filters. 4840 4841 ``tail``: the filter is inserted at the tail of the filter list, 4842 behind any existing filters (default). 4843 4844 ``id=<id>``: the filter is inserted before or behind the filter 4845 specified by <id>, see the insert option below. 4846 4847 insert behind\|before is an option to specify where to insert 4848 the new filter relative to the one specified with 4849 position=id=<id>. It can be applied to any netfilter. 4850 4851 ``before``: insert before the specified filter. 4852 4853 ``behind``: insert behind the specified filter (default). 4854 4855 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4856 filter-mirror on netdev netdevid,mirror net packet to 4857 chardevchardevid, if it has the vnet\_hdr\_support flag, 4858 filter-mirror will mirror packet with vnet\_hdr\_len. 4859 4860 ``-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]`` 4861 filter-redirector on netdev netdevid,redirect filter's net 4862 packet to chardev chardevid,and redirect indev's packet to 4863 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4864 will redirect packet with vnet\_hdr\_len. Create a 4865 filter-redirector we need to differ outdev id from indev id, id 4866 can not be the same. we can just use indev or outdev, but at 4867 least one of indev or outdev need to be specified. 4868 4869 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4870 Filter-rewriter is a part of COLO project.It will rewrite tcp 4871 packet to secondary from primary to keep secondary tcp 4872 connection,and rewrite tcp packet to primary from secondary make 4873 tcp packet can be handled by client.if it has the 4874 vnet\_hdr\_support flag, we can parse packet with vnet header. 4875 4876 usage: colo secondary: -object 4877 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4878 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4879 filter-rewriter,id=rew0,netdev=hn0,queue=all 4880 4881 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4882 Dump the network traffic on netdev dev to the file specified by 4883 filename. At most len bytes (64k by default) per packet are 4884 stored. The file format is libpcap, so it can be analyzed with 4885 tools such as tcpdump or Wireshark. 4886 4887 ``-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}]`` 4888 Colo-compare gets packet from primary\_in chardevid and 4889 secondary\_in, then compare whether the payload of primary packet 4890 and secondary packet are the same. If same, it will output 4891 primary packet to out\_dev, else it will notify COLO-framework to do 4892 checkpoint and send primary packet to out\_dev. In order to 4893 improve efficiency, we need to put the task of comparison in 4894 another iothread. If it has the vnet\_hdr\_support flag, 4895 colo compare will send/recv packet with vnet\_hdr\_len. 4896 The compare\_timeout=@var{ms} determines the maximum time of the 4897 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4898 is to set the period of scanning expired primary node network packets. 4899 The max\_queue\_size=@var{size} is to set the max compare queue 4900 size depend on user environment. 4901 If user want to use Xen COLO, need to add the notify\_dev to 4902 notify Xen colo-frame to do checkpoint. 4903 4904 COLO-compare must be used with the help of filter-mirror, 4905 filter-redirector and filter-rewriter. 4906 4907 :: 4908 4909 KVM COLO 4910 4911 primary: 4912 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4913 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4914 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4915 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4916 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4917 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4918 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4919 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4920 -object iothread,id=iothread1 4921 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4922 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4923 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4924 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4925 4926 secondary: 4927 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4928 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4929 -chardev socket,id=red0,host=3.3.3.3,port=9003 4930 -chardev socket,id=red1,host=3.3.3.3,port=9004 4931 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4932 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4933 4934 4935 Xen COLO 4936 4937 primary: 4938 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4939 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4940 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4941 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4942 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4943 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4944 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4945 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4946 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4947 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4948 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4949 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4950 -object iothread,id=iothread1 4951 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4952 4953 secondary: 4954 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4955 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4956 -chardev socket,id=red0,host=3.3.3.3,port=9003 4957 -chardev socket,id=red1,host=3.3.3.3,port=9004 4958 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4959 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4960 4961 If you want to know the detail of above command line, you can 4962 read the colo-compare git log. 4963 4964 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4965 Creates a cryptodev backend which executes crypto opreation from 4966 the QEMU cipher APIS. The id parameter is a unique ID that will 4967 be used to reference this cryptodev backend from the 4968 ``virtio-crypto`` device. The queues parameter is optional, 4969 which specify the queue number of cryptodev backend, the default 4970 of queues is 1. 4971 4972 .. parsed-literal:: 4973 4974 # |qemu_system| \\ 4975 [...] \\ 4976 -object cryptodev-backend-builtin,id=cryptodev0 \\ 4977 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4978 [...] 4979 4980 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 4981 Creates a vhost-user cryptodev backend, backed by a chardev 4982 chardevid. The id parameter is a unique ID that will be used to 4983 reference this cryptodev backend from the ``virtio-crypto`` 4984 device. The chardev should be a unix domain socket backed one. 4985 The vhost-user uses a specifically defined protocol to pass 4986 vhost ioctl replacement messages to an application on the other 4987 end of the socket. The queues parameter is optional, which 4988 specify the queue number of cryptodev backend for multiqueue 4989 vhost-user, the default of queues is 1. 4990 4991 .. parsed-literal:: 4992 4993 # |qemu_system| \\ 4994 [...] \\ 4995 -chardev socket,id=chardev0,path=/path/to/socket \\ 4996 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 4997 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 4998 [...] 4999 5000 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5001 \ 5002 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5003 Defines a secret to store a password, encryption key, or some 5004 other sensitive data. The sensitive data can either be passed 5005 directly via the data parameter, or indirectly via the file 5006 parameter. Using the data parameter is insecure unless the 5007 sensitive data is encrypted. 5008 5009 The sensitive data can be provided in raw format (the default), 5010 or base64. When encoded as JSON, the raw format only supports 5011 valid UTF-8 characters, so base64 is recommended for sending 5012 binary data. QEMU will convert from which ever format is 5013 provided to the format it needs internally. eg, an RBD password 5014 can be provided in raw format, even though it will be base64 5015 encoded when passed onto the RBD sever. 5016 5017 For added protection, it is possible to encrypt the data 5018 associated with a secret using the AES-256-CBC cipher. Use of 5019 encryption is indicated by providing the keyid and iv 5020 parameters. The keyid parameter provides the ID of a previously 5021 defined secret that contains the AES-256 decryption key. This 5022 key should be 32-bytes long and be base64 encoded. The iv 5023 parameter provides the random initialization vector used for 5024 encryption of this particular secret and should be a base64 5025 encrypted string of the 16-byte IV. 5026 5027 The simplest (insecure) usage is to provide the secret inline 5028 5029 .. parsed-literal:: 5030 5031 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5032 5033 The simplest secure usage is to provide the secret via a file 5034 5035 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5036 secret,id=sec0,file=mypasswd.txt,format=raw 5037 5038 For greater security, AES-256-CBC should be used. To illustrate 5039 usage, consider the openssl command line tool which can encrypt 5040 the data. Note that when encrypting, the plaintext must be 5041 padded to the cipher block size (32 bytes) using the standard 5042 PKCS#5/6 compatible padding algorithm. 5043 5044 First a master key needs to be created in base64 encoding: 5045 5046 :: 5047 5048 # openssl rand -base64 32 > key.b64 5049 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5050 5051 Each secret to be encrypted needs to have a random 5052 initialization vector generated. These do not need to be kept 5053 secret 5054 5055 :: 5056 5057 # openssl rand -base64 16 > iv.b64 5058 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5059 5060 The secret to be defined can now be encrypted, in this case 5061 we're telling openssl to base64 encode the result, but it could 5062 be left as raw bytes if desired. 5063 5064 :: 5065 5066 # SECRET=$(printf "letmein" | 5067 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5068 5069 When launching QEMU, create a master secret pointing to 5070 ``key.b64`` and specify that to be used to decrypt the user 5071 password. Pass the contents of ``iv.b64`` to the second secret 5072 5073 .. parsed-literal:: 5074 5075 # |qemu_system| \\ 5076 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5077 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5078 data=$SECRET,iv=$(<iv.b64) 5079 5080 ``-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]`` 5081 Create a Secure Encrypted Virtualization (SEV) guest object, 5082 which can be used to provide the guest memory encryption support 5083 on AMD processors. 5084 5085 When memory encryption is enabled, one of the physical address 5086 bit (aka the C-bit) is utilized to mark if a memory page is 5087 protected. The ``cbitpos`` is used to provide the C-bit 5088 position. The C-bit position is Host family dependent hence user 5089 must provide this value. On EPYC, the value should be 47. 5090 5091 When memory encryption is enabled, we loose certain bits in 5092 physical address space. The ``reduced-phys-bits`` is used to 5093 provide the number of bits we loose in physical address space. 5094 Similar to C-bit, the value is Host family dependent. On EPYC, 5095 the value should be 5. 5096 5097 The ``sev-device`` provides the device file to use for 5098 communicating with the SEV firmware running inside AMD Secure 5099 Processor. The default device is '/dev/sev'. If hardware 5100 supports memory encryption then /dev/sev devices are created by 5101 CCP driver. 5102 5103 The ``policy`` provides the guest policy to be enforced by the 5104 SEV firmware and restrict what configuration and operational 5105 commands can be performed on this guest by the hypervisor. The 5106 policy should be provided by the guest owner and is bound to the 5107 guest and cannot be changed throughout the lifetime of the 5108 guest. The default is 0. 5109 5110 If guest ``policy`` allows sharing the key with another SEV 5111 guest then ``handle`` can be use to provide handle of the guest 5112 from which to share the key. 5113 5114 The ``dh-cert-file`` and ``session-file`` provides the guest 5115 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5116 and session parameters are used for establishing a cryptographic 5117 session with the guest owner to negotiate keys used for 5118 attestation. The file must be encoded in base64. 5119 5120 e.g to launch a SEV guest 5121 5122 .. parsed-literal:: 5123 5124 # |qemu_system_x86| \\ 5125 ...... \\ 5126 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5127 -machine ...,memory-encryption=sev0 \\ 5128 ..... 5129 5130 ``-object authz-simple,id=id,identity=string`` 5131 Create an authorization object that will control access to 5132 network services. 5133 5134 The ``identity`` parameter is identifies the user and its format 5135 depends on the network service that authorization object is 5136 associated with. For authorizing based on TLS x509 certificates, 5137 the identity must be the x509 distinguished name. Note that care 5138 must be taken to escape any commas in the distinguished name. 5139 5140 An example authorization object to validate a x509 distinguished 5141 name would look like: 5142 5143 .. parsed-literal:: 5144 5145 # |qemu_system| \\ 5146 ... \\ 5147 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5148 ... 5149 5150 Note the use of quotes due to the x509 distinguished name 5151 containing whitespace, and escaping of ','. 5152 5153 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5154 Create an authorization object that will control access to 5155 network services. 5156 5157 The ``filename`` parameter is the fully qualified path to a file 5158 containing the access control list rules in JSON format. 5159 5160 An example set of rules that match against SASL usernames might 5161 look like: 5162 5163 :: 5164 5165 { 5166 "rules": [ 5167 { "match": "fred", "policy": "allow", "format": "exact" }, 5168 { "match": "bob", "policy": "allow", "format": "exact" }, 5169 { "match": "danb", "policy": "deny", "format": "glob" }, 5170 { "match": "dan*", "policy": "allow", "format": "exact" }, 5171 ], 5172 "policy": "deny" 5173 } 5174 5175 When checking access the object will iterate over all the rules 5176 and the first rule to match will have its ``policy`` value 5177 returned as the result. If no rules match, then the default 5178 ``policy`` value is returned. 5179 5180 The rules can either be an exact string match, or they can use 5181 the simple UNIX glob pattern matching to allow wildcards to be 5182 used. 5183 5184 If ``refresh`` is set to true the file will be monitored and 5185 automatically reloaded whenever its content changes. 5186 5187 As with the ``authz-simple`` object, the format of the identity 5188 strings being matched depends on the network service, but is 5189 usually a TLS x509 distinguished name, or a SASL username. 5190 5191 An example authorization object to validate a SASL username 5192 would look like: 5193 5194 .. parsed-literal:: 5195 5196 # |qemu_system| \\ 5197 ... \\ 5198 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5199 ... 5200 5201 ``-object authz-pam,id=id,service=string`` 5202 Create an authorization object that will control access to 5203 network services. 5204 5205 The ``service`` parameter provides the name of a PAM service to 5206 use for authorization. It requires that a file 5207 ``/etc/pam.d/service`` exist to provide the configuration for 5208 the ``account`` subsystem. 5209 5210 An example authorization object to validate a TLS x509 5211 distinguished name would look like: 5212 5213 .. parsed-literal:: 5214 5215 # |qemu_system| \\ 5216 ... \\ 5217 -object authz-pam,id=auth0,service=qemu-vnc \\ 5218 ... 5219 5220 There would then be a corresponding config file for PAM at 5221 ``/etc/pam.d/qemu-vnc`` that contains: 5222 5223 :: 5224 5225 account requisite pam_listfile.so item=user sense=allow \ 5226 file=/etc/qemu/vnc.allow 5227 5228 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5229 of x509 distingished names that are permitted access 5230 5231 :: 5232 5233 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5234 5235 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5236 Creates a dedicated event loop thread that devices can be 5237 assigned to. This is known as an IOThread. By default device 5238 emulation happens in vCPU threads or the main event loop thread. 5239 This can become a scalability bottleneck. IOThreads allow device 5240 emulation and I/O to run on other host CPUs. 5241 5242 The ``id`` parameter is a unique ID that will be used to 5243 reference this IOThread from ``-device ...,iothread=id``. 5244 Multiple devices can be assigned to an IOThread. Note that not 5245 all devices support an ``iothread`` parameter. 5246 5247 The ``query-iothreads`` QMP command lists IOThreads and reports 5248 their thread IDs so that the user can configure host CPU 5249 pinning/affinity. 5250 5251 IOThreads use an adaptive polling algorithm to reduce event loop 5252 latency. Instead of entering a blocking system call to monitor 5253 file descriptors and then pay the cost of being woken up when an 5254 event occurs, the polling algorithm spins waiting for events for 5255 a short time. The algorithm's default parameters are suitable 5256 for many cases but can be adjusted based on knowledge of the 5257 workload and/or host device latency. 5258 5259 The ``poll-max-ns`` parameter is the maximum number of 5260 nanoseconds to busy wait for events. Polling can be disabled by 5261 setting this value to 0. 5262 5263 The ``poll-grow`` parameter is the multiplier used to increase 5264 the polling time when the algorithm detects it is missing events 5265 due to not polling long enough. 5266 5267 The ``poll-shrink`` parameter is the divisor used to decrease 5268 the polling time when the algorithm detects it is spending too 5269 long polling without encountering events. 5270 5271 The polling parameters can be modified at run-time using the 5272 ``qom-set`` command (where ``iothread1`` is the IOThread's 5273 ``id``): 5274 5275 :: 5276 5277 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5278ERST 5279 5280 5281HXCOMM This is the last statement. Insert new options before this line! 5282 5283#undef DEF 5284#undef DEFHEADING 5285#undef ARCHHEADING 5286
