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 :: 107 108 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 109 -machine memory-backend=pc.ram 110 -m 512M 111 112 Migration compatibility note: 113 114 * as backend id one shall use value of 'default-ram-id', advertised by 115 machine type (available via ``query-machines`` QMP command), if migration 116 to/from old QEMU (<5.0) is expected. 117 * for machine types 4.0 and older, user shall 118 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 119 if migration to/from old QEMU (<5.0) is expected. 120 121 For example: 122 :: 123 124 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 125 -machine memory-backend=pc.ram 126 -m 512M 127ERST 128 129DEF("M", HAS_ARG, QEMU_OPTION_M, 130 " sgx-epc.0.memdev=memid\n", 131 QEMU_ARCH_ALL) 132 133SRST 134``sgx-epc.0.memdev=@var{memid}`` 135 Define an SGX EPC section. 136ERST 137 138DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 139 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 140SRST 141``-cpu model`` 142 Select CPU model (``-cpu help`` for list and additional feature 143 selection) 144ERST 145 146DEF("accel", HAS_ARG, QEMU_OPTION_accel, 147 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 148 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 149 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 150 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 151 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 152 " split-wx=on|off (enable TCG split w^x mapping)\n" 153 " tb-size=n (TCG translation block cache size)\n" 154 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 155 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 156SRST 157``-accel name[,prop=value[,...]]`` 158 This is used to enable an accelerator. Depending on the target 159 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 160 default, tcg is used. If there is more than one accelerator 161 specified, the next one is used if the previous one fails to 162 initialize. 163 164 ``igd-passthru=on|off`` 165 When Xen is in use, this option controls whether Intel 166 integrated graphics devices can be passed through to the guest 167 (default=off) 168 169 ``kernel-irqchip=on|off|split`` 170 Controls KVM in-kernel irqchip support. The default is full 171 acceleration of the interrupt controllers. On x86, split irqchip 172 reduces the kernel attack surface, at a performance cost for 173 non-MSI interrupts. Disabling the in-kernel irqchip completely 174 is not recommended except for debugging purposes. 175 176 ``kvm-shadow-mem=size`` 177 Defines the size of the KVM shadow MMU. 178 179 ``split-wx=on|off`` 180 Controls the use of split w^x mapping for the TCG code generation 181 buffer. Some operating systems require this to be enabled, and in 182 such a case this will default on. On other operating systems, this 183 will default off, but one may enable this for testing or debugging. 184 185 ``tb-size=n`` 186 Controls the size (in MiB) of the TCG translation block cache. 187 188 ``thread=single|multi`` 189 Controls number of TCG threads. When the TCG is multi-threaded 190 there will be one thread per vCPU therefore taking advantage of 191 additional host cores. The default is to enable multi-threading 192 where both the back-end and front-ends support it and no 193 incompatible TCG features have been enabled (e.g. 194 icount/replay). 195 196 ``dirty-ring-size=n`` 197 When the KVM accelerator is used, it controls the size of the per-vCPU 198 dirty page ring buffer (number of entries for each vCPU). It should 199 be a value that is power of two, and it should be 1024 or bigger (but 200 still less than the maximum value that the kernel supports). 4096 201 could be a good initial value if you have no idea which is the best. 202 Set this value to 0 to disable the feature. By default, this feature 203 is disabled (dirty-ring-size=0). When enabled, KVM will instead 204 record dirty pages in a bitmap. 205 206ERST 207 208DEF("smp", HAS_ARG, QEMU_OPTION_smp, 209 "-smp [[cpus=]n][,maxcpus=cpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]\n" 210 " set the number of CPUs to 'n' [default=1]\n" 211 " maxcpus= maximum number of total CPUs, including\n" 212 " offline CPUs for hotplug, etc\n" 213 " sockets= number of discrete sockets in the system\n" 214 " dies= number of CPU dies on one socket (for PC only)\n" 215 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 216 " threads= number of threads on one CPU core\n", 217 QEMU_ARCH_ALL) 218SRST 219``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]`` 220 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 221 the machine type board. On boards supporting CPU hotplug, the optional 222 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 223 added at runtime. When both parameters are omitted, the maximum number 224 of CPUs will be calculated from the provided topology members and the 225 initial CPU count will match the maximum number. When only one of them 226 is given then the omitted one will be set to its counterpart's value. 227 Both parameters may be specified, but the maximum number of CPUs must 228 be equal to or greater than the initial CPU count. Both parameters are 229 subject to an upper limit that is determined by the specific machine 230 type chosen. 231 232 To control reporting of CPU topology information, the number of sockets, 233 dies per socket, cores per die, and threads per core can be specified. 234 The sum `` sockets * cores * dies * threads `` must be equal to the 235 maximum CPU count. CPU targets may only support a subset of the topology 236 parameters. Where a CPU target does not support use of a particular 237 topology parameter, its value should be assumed to be 1 for the purpose 238 of computing the CPU maximum count. 239 240 Either the initial CPU count, or at least one of the topology parameters 241 must be specified. The specified parameters must be greater than zero, 242 explicit configuration like "cpus=0" is not allowed. Values for any 243 omitted parameters will be computed from those which are given. 244 Historically preference was given to the coarsest topology parameters 245 when computing missing values (ie sockets preferred over cores, which 246 were preferred over threads), however, this behaviour is considered 247 liable to change. 248ERST 249 250DEF("numa", HAS_ARG, QEMU_OPTION_numa, 251 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 252 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 253 "-numa dist,src=source,dst=destination,val=distance\n" 254 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 255 "-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" 256 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 257 QEMU_ARCH_ALL) 258SRST 259``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 260 \ 261``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 262 \ 263``-numa dist,src=source,dst=destination,val=distance`` 264 \ 265``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 266 \ 267``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 268 \ 269``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 270 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 271 distance from a source node to a destination node. Set the ACPI 272 Heterogeneous Memory Attributes for the given nodes. 273 274 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 275 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 276 contiguous range of CPU indexes (or a single VCPU if lastcpu is 277 omitted). A non-contiguous set of VCPUs can be represented by 278 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 279 omitted on all nodes, VCPUs are automatically split between them. 280 281 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 282 NUMA node: 283 284 :: 285 286 -numa node,cpus=0-2,cpus=5 287 288 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 289 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 290 assign CPU objects to a node using topology layout properties of 291 CPU. The set of properties is machine specific, and depends on used 292 machine type/'\ ``smp``\ ' options. It could be queried with 293 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 294 property specifies node to which CPU object will be assigned, it's 295 required for node to be declared with '\ ``node``\ ' option before 296 it's used with '\ ``cpu``\ ' option. 297 298 For example: 299 300 :: 301 302 -M pc \ 303 -smp 1,sockets=2,maxcpus=2 \ 304 -numa node,nodeid=0 -numa node,nodeid=1 \ 305 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 306 307 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 308 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 309 a given memory backend device to a node. If '\ ``mem``\ ' and 310 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 311 312 313 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 314 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 315 use it. 316 317 '\ ``initiator``\ ' is an additional option that points to an 318 initiator NUMA node that has best performance (the lowest latency or 319 largest bandwidth) to this NUMA node. Note that this option can be 320 set only when the machine property 'hmat' is set to 'on'. 321 322 Following example creates a machine with 2 NUMA nodes, node 0 has 323 CPU. node 1 has only memory, and its initiator is node 0. Note that 324 because node 0 has CPU, by default the initiator of node 0 is itself 325 and must be itself. 326 327 :: 328 329 -machine hmat=on \ 330 -m 2G,slots=2,maxmem=4G \ 331 -object memory-backend-ram,size=1G,id=m0 \ 332 -object memory-backend-ram,size=1G,id=m1 \ 333 -numa node,nodeid=0,memdev=m0 \ 334 -numa node,nodeid=1,memdev=m1,initiator=0 \ 335 -smp 2,sockets=2,maxcpus=2 \ 336 -numa cpu,node-id=0,socket-id=0 \ 337 -numa cpu,node-id=0,socket-id=1 338 339 source and destination are NUMA node IDs. distance is the NUMA 340 distance from source to destination. The distance from a node to 341 itself is always 10. If any pair of nodes is given a distance, then 342 all pairs must be given distances. Although, when distances are only 343 given in one direction for each pair of nodes, then the distances in 344 the opposite directions are assumed to be the same. If, however, an 345 asymmetrical pair of distances is given for even one node pair, then 346 all node pairs must be provided distance values for both directions, 347 even when they are symmetrical. When a node is unreachable from 348 another node, set the pair's distance to 255. 349 350 Note that the -``numa`` option doesn't allocate any of the specified 351 resources, it just assigns existing resources to NUMA nodes. This 352 means that one still has to use the ``-m``, ``-smp`` options to 353 allocate RAM and VCPUs respectively. 354 355 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 356 Information between initiator and target NUMA nodes in ACPI 357 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 358 create memory requests, usually it has one or more processors. 359 Target NUMA node contains addressable memory. 360 361 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 362 the memory hierarchy of the target NUMA node: if hierarchy is 363 'memory', the structure represents the memory performance; if 364 hierarchy is 'first-level\|second-level\|third-level', this 365 structure represents aggregated performance of memory side caches 366 for each domain. type of 'data-type' is type of data represented by 367 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 368 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 369 the target memory; if 'hierarchy' is 370 'first-level\|second-level\|third-level', 'data-type' is 371 'access\|read\|write' hit latency or 'access\|read\|write' hit 372 bandwidth of the target memory side cache. 373 374 lat is latency value in nanoseconds. bw is bandwidth value, the 375 possible value and units are NUM[M\|G\|T], mean that the bandwidth 376 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 377 used suffix). Note that if latency or bandwidth value is 0, means 378 the corresponding latency or bandwidth information is not provided. 379 380 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 381 belongs. size is the size of memory side cache in bytes. level is 382 the cache level described in this structure, note that the cache 383 level 0 should not be used with '\ ``hmat-cache``\ ' option. 384 associativity is the cache associativity, the possible value is 385 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 386 is the write policy. line is the cache Line size in bytes. 387 388 For example, the following options describe 2 NUMA nodes. Node 0 has 389 2 cpus and a ram, node 1 has only a ram. The processors in node 0 390 access memory in node 0 with access-latency 5 nanoseconds, 391 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 392 memory in NUMA node 1 with access-latency 10 nanoseconds, 393 access-bandwidth is 100 MB/s. And for memory side cache information, 394 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 395 policy is write-back, the cache Line size is 8 bytes: 396 397 :: 398 399 -machine hmat=on \ 400 -m 2G \ 401 -object memory-backend-ram,size=1G,id=m0 \ 402 -object memory-backend-ram,size=1G,id=m1 \ 403 -smp 2 \ 404 -numa node,nodeid=0,memdev=m0 \ 405 -numa node,nodeid=1,memdev=m1,initiator=0 \ 406 -numa cpu,node-id=0,socket-id=0 \ 407 -numa cpu,node-id=0,socket-id=1 \ 408 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 409 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 410 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 411 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 412 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 413 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 414ERST 415 416DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 417 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 418 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 419SRST 420``-add-fd fd=fd,set=set[,opaque=opaque]`` 421 Add a file descriptor to an fd set. Valid options are: 422 423 ``fd=fd`` 424 This option defines the file descriptor of which a duplicate is 425 added to fd set. The file descriptor cannot be stdin, stdout, or 426 stderr. 427 428 ``set=set`` 429 This option defines the ID of the fd set to add the file 430 descriptor to. 431 432 ``opaque=opaque`` 433 This option defines a free-form string that can be used to 434 describe fd. 435 436 You can open an image using pre-opened file descriptors from an fd 437 set: 438 439 .. parsed-literal:: 440 441 |qemu_system| \\ 442 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 443 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 444 -drive file=/dev/fdset/2,index=0,media=disk 445ERST 446 447DEF("set", HAS_ARG, QEMU_OPTION_set, 448 "-set group.id.arg=value\n" 449 " set <arg> parameter for item <id> of type <group>\n" 450 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 451SRST 452``-set group.id.arg=value`` 453 Set parameter arg for item id of type group 454ERST 455 456DEF("global", HAS_ARG, QEMU_OPTION_global, 457 "-global driver.property=value\n" 458 "-global driver=driver,property=property,value=value\n" 459 " set a global default for a driver property\n", 460 QEMU_ARCH_ALL) 461SRST 462``-global driver.prop=value`` 463 \ 464``-global driver=driver,property=property,value=value`` 465 Set default value of driver's property prop to value, e.g.: 466 467 .. parsed-literal:: 468 469 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 470 471 In particular, you can use this to set driver properties for devices 472 which are created automatically by the machine model. To create a 473 device which is not created automatically and set properties on it, 474 use -``device``. 475 476 -global driver.prop=value is shorthand for -global 477 driver=driver,property=prop,value=value. The longhand syntax works 478 even when driver contains a dot. 479ERST 480 481DEF("boot", HAS_ARG, QEMU_OPTION_boot, 482 "-boot [order=drives][,once=drives][,menu=on|off]\n" 483 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 484 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 485 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 486 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 487 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 488 QEMU_ARCH_ALL) 489SRST 490``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 491 Specify boot order drives as a string of drive letters. Valid drive 492 letters depend on the target architecture. The x86 PC uses: a, b 493 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 494 (Etherboot from network adapter 1-4), hard disk boot is the default. 495 To apply a particular boot order only on the first startup, specify 496 it via ``once``. Note that the ``order`` or ``once`` parameter 497 should not be used together with the ``bootindex`` property of 498 devices, since the firmware implementations normally do not support 499 both at the same time. 500 501 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 502 as firmware/BIOS supports them. The default is non-interactive boot. 503 504 A splash picture could be passed to bios, enabling user to show it 505 as logo, when option splash=sp\_name is given and menu=on, If 506 firmware/BIOS supports them. Currently Seabios for X86 system 507 support it. limitation: The splash file could be a jpeg file or a 508 BMP file in 24 BPP format(true color). The resolution should be 509 supported by the SVGA mode, so the recommended is 320x240, 640x480, 510 800x640. 511 512 A timeout could be passed to bios, guest will pause for rb\_timeout 513 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 514 not reboot, qemu passes '-1' to bios by default. Currently Seabios 515 for X86 system support it. 516 517 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 518 it. This only effects when boot priority is changed by bootindex 519 options. The default is non-strict boot. 520 521 .. parsed-literal:: 522 523 # try to boot from network first, then from hard disk 524 |qemu_system_x86| -boot order=nc 525 # boot from CD-ROM first, switch back to default order after reboot 526 |qemu_system_x86| -boot once=d 527 # boot with a splash picture for 5 seconds. 528 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 529 530 Note: The legacy format '-boot drives' is still supported but its 531 use is discouraged as it may be removed from future versions. 532ERST 533 534DEF("m", HAS_ARG, QEMU_OPTION_m, 535 "-m [size=]megs[,slots=n,maxmem=size]\n" 536 " configure guest RAM\n" 537 " size: initial amount of guest memory\n" 538 " slots: number of hotplug slots (default: none)\n" 539 " maxmem: maximum amount of guest memory (default: none)\n" 540 "NOTE: Some architectures might enforce a specific granularity\n", 541 QEMU_ARCH_ALL) 542SRST 543``-m [size=]megs[,slots=n,maxmem=size]`` 544 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 545 Optionally, a suffix of "M" or "G" can be used to signify a value in 546 megabytes or gigabytes respectively. Optional pair slots, maxmem 547 could be used to set amount of hotpluggable memory slots and maximum 548 amount of memory. Note that maxmem must be aligned to the page size. 549 550 For example, the following command-line sets the guest startup RAM 551 size to 1GB, creates 3 slots to hotplug additional memory and sets 552 the maximum memory the guest can reach to 4GB: 553 554 .. parsed-literal:: 555 556 |qemu_system| -m 1G,slots=3,maxmem=4G 557 558 If slots and maxmem are not specified, memory hotplug won't be 559 enabled and the guest startup RAM will never increase. 560ERST 561 562DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 563 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 564SRST 565``-mem-path path`` 566 Allocate guest RAM from a temporarily created file in path. 567ERST 568 569DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 570 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 571 QEMU_ARCH_ALL) 572SRST 573``-mem-prealloc`` 574 Preallocate memory when using -mem-path. 575ERST 576 577DEF("k", HAS_ARG, QEMU_OPTION_k, 578 "-k language use keyboard layout (for example 'fr' for French)\n", 579 QEMU_ARCH_ALL) 580SRST 581``-k language`` 582 Use keyboard layout language (for example ``fr`` for French). This 583 option is only needed where it is not easy to get raw PC keycodes 584 (e.g. on Macs, with some X11 servers or with a VNC or curses 585 display). You don't normally need to use it on PC/Linux or 586 PC/Windows hosts. 587 588 The available layouts are: 589 590 :: 591 592 ar de-ch es fo fr-ca hu ja mk no pt-br sv 593 da en-gb et fr fr-ch is lt nl pl ru th 594 de en-us fi fr-be hr it lv nl-be pt sl tr 595 596 The default is ``en-us``. 597ERST 598 599 600HXCOMM Deprecated by -audiodev 601DEF("audio-help", 0, QEMU_OPTION_audio_help, 602 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 603 QEMU_ARCH_ALL) 604SRST 605``-audio-help`` 606 Will show the -audiodev equivalent of the currently specified 607 (deprecated) environment variables. 608ERST 609 610DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 611 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 612 " specifies the audio backend to use\n" 613 " id= identifier of the backend\n" 614 " timer-period= timer period in microseconds\n" 615 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 616 " in|out.fixed-settings= use fixed settings for host audio\n" 617 " in|out.frequency= frequency to use with fixed settings\n" 618 " in|out.channels= number of channels to use with fixed settings\n" 619 " in|out.format= sample format to use with fixed settings\n" 620 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 621 " in|out.voices= number of voices to use\n" 622 " in|out.buffer-length= length of buffer in microseconds\n" 623 "-audiodev none,id=id,[,prop[=value][,...]]\n" 624 " dummy driver that discards all output\n" 625#ifdef CONFIG_AUDIO_ALSA 626 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 627 " in|out.dev= name of the audio device to use\n" 628 " in|out.period-length= length of period in microseconds\n" 629 " in|out.try-poll= attempt to use poll mode\n" 630 " threshold= threshold (in microseconds) when playback starts\n" 631#endif 632#ifdef CONFIG_AUDIO_COREAUDIO 633 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 634 " in|out.buffer-count= number of buffers\n" 635#endif 636#ifdef CONFIG_AUDIO_DSOUND 637 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 638 " latency= add extra latency to playback in microseconds\n" 639#endif 640#ifdef CONFIG_AUDIO_OSS 641 "-audiodev oss,id=id[,prop[=value][,...]]\n" 642 " in|out.dev= path of the audio device to use\n" 643 " in|out.buffer-count= number of buffers\n" 644 " in|out.try-poll= attempt to use poll mode\n" 645 " try-mmap= try using memory mapped access\n" 646 " exclusive= open device in exclusive mode\n" 647 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 648#endif 649#ifdef CONFIG_AUDIO_PA 650 "-audiodev pa,id=id[,prop[=value][,...]]\n" 651 " server= PulseAudio server address\n" 652 " in|out.name= source/sink device name\n" 653 " in|out.latency= desired latency in microseconds\n" 654#endif 655#ifdef CONFIG_AUDIO_SDL 656 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 657 " in|out.buffer-count= number of buffers\n" 658#endif 659#ifdef CONFIG_SPICE 660 "-audiodev spice,id=id[,prop[=value][,...]]\n" 661#endif 662 "-audiodev wav,id=id[,prop[=value][,...]]\n" 663 " path= path of wav file to record\n", 664 QEMU_ARCH_ALL) 665SRST 666``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 667 Adds a new audio backend driver identified by id. There are global 668 and driver specific properties. Some values can be set differently 669 for input and output, they're marked with ``in|out.``. You can set 670 the input's property with ``in.prop`` and the output's property with 671 ``out.prop``. For example: 672 673 :: 674 675 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 676 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 677 678 NOTE: parameter validation is known to be incomplete, in many cases 679 specifying an invalid option causes QEMU to print an error message 680 and continue emulation without sound. 681 682 Valid global options are: 683 684 ``id=identifier`` 685 Identifies the audio backend. 686 687 ``timer-period=period`` 688 Sets the timer period used by the audio subsystem in 689 microseconds. Default is 10000 (10 ms). 690 691 ``in|out.mixing-engine=on|off`` 692 Use QEMU's mixing engine to mix all streams inside QEMU and 693 convert audio formats when not supported by the backend. When 694 off, fixed-settings must be off too. Note that disabling this 695 option means that the selected backend must support multiple 696 streams and the audio formats used by the virtual cards, 697 otherwise you'll get no sound. It's not recommended to disable 698 this option unless you want to use 5.1 or 7.1 audio, as mixing 699 engine only supports mono and stereo audio. Default is on. 700 701 ``in|out.fixed-settings=on|off`` 702 Use fixed settings for host audio. When off, it will change 703 based on how the guest opens the sound card. In this case you 704 must not specify frequency, channels or format. Default is on. 705 706 ``in|out.frequency=frequency`` 707 Specify the frequency to use when using fixed-settings. Default 708 is 44100Hz. 709 710 ``in|out.channels=channels`` 711 Specify the number of channels to use when using fixed-settings. 712 Default is 2 (stereo). 713 714 ``in|out.format=format`` 715 Specify the sample format to use when using fixed-settings. 716 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 717 ``u32``, ``f32``. Default is ``s16``. 718 719 ``in|out.voices=voices`` 720 Specify the number of voices to use. Default is 1. 721 722 ``in|out.buffer-length=usecs`` 723 Sets the size of the buffer in microseconds. 724 725``-audiodev none,id=id[,prop[=value][,...]]`` 726 Creates a dummy backend that discards all outputs. This backend has 727 no backend specific properties. 728 729``-audiodev alsa,id=id[,prop[=value][,...]]`` 730 Creates backend using the ALSA. This backend is only available on 731 Linux. 732 733 ALSA specific options are: 734 735 ``in|out.dev=device`` 736 Specify the ALSA device to use for input and/or output. Default 737 is ``default``. 738 739 ``in|out.period-length=usecs`` 740 Sets the period length in microseconds. 741 742 ``in|out.try-poll=on|off`` 743 Attempt to use poll mode with the device. Default is on. 744 745 ``threshold=threshold`` 746 Threshold (in microseconds) when playback starts. Default is 0. 747 748``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 749 Creates a backend using Apple's Core Audio. This backend is only 750 available on Mac OS and only supports playback. 751 752 Core Audio specific options are: 753 754 ``in|out.buffer-count=count`` 755 Sets the count of the buffers. 756 757``-audiodev dsound,id=id[,prop[=value][,...]]`` 758 Creates a backend using Microsoft's DirectSound. This backend is 759 only available on Windows and only supports playback. 760 761 DirectSound specific options are: 762 763 ``latency=usecs`` 764 Add extra usecs microseconds latency to playback. Default is 765 10000 (10 ms). 766 767``-audiodev oss,id=id[,prop[=value][,...]]`` 768 Creates a backend using OSS. This backend is available on most 769 Unix-like systems. 770 771 OSS specific options are: 772 773 ``in|out.dev=device`` 774 Specify the file name of the OSS device to use. Default is 775 ``/dev/dsp``. 776 777 ``in|out.buffer-count=count`` 778 Sets the count of the buffers. 779 780 ``in|out.try-poll=on|of`` 781 Attempt to use poll mode with the device. Default is on. 782 783 ``try-mmap=on|off`` 784 Try using memory mapped device access. Default is off. 785 786 ``exclusive=on|off`` 787 Open the device in exclusive mode (vmix won't work in this 788 case). Default is off. 789 790 ``dsp-policy=policy`` 791 Sets the timing policy (between 0 and 10, where smaller number 792 means smaller latency but higher CPU usage). Use -1 to use 793 buffer sizes specified by ``buffer`` and ``buffer-count``. This 794 option is ignored if you do not have OSS 4. Default is 5. 795 796``-audiodev pa,id=id[,prop[=value][,...]]`` 797 Creates a backend using PulseAudio. This backend is available on 798 most systems. 799 800 PulseAudio specific options are: 801 802 ``server=server`` 803 Sets the PulseAudio server to connect to. 804 805 ``in|out.name=sink`` 806 Use the specified source/sink for recording/playback. 807 808 ``in|out.latency=usecs`` 809 Desired latency in microseconds. The PulseAudio server will try 810 to honor this value but actual latencies may be lower or higher. 811 812``-audiodev sdl,id=id[,prop[=value][,...]]`` 813 Creates a backend using SDL. This backend is available on most 814 systems, but you should use your platform's native backend if 815 possible. 816 817 SDL specific options are: 818 819 ``in|out.buffer-count=count`` 820 Sets the count of the buffers. 821 822``-audiodev spice,id=id[,prop[=value][,...]]`` 823 Creates a backend that sends audio through SPICE. This backend 824 requires ``-spice`` and automatically selected in that case, so 825 usually you can ignore this option. This backend has no backend 826 specific properties. 827 828``-audiodev wav,id=id[,prop[=value][,...]]`` 829 Creates a backend that writes audio to a WAV file. 830 831 Backend specific options are: 832 833 ``path=path`` 834 Write recorded audio into the specified file. Default is 835 ``qemu.wav``. 836ERST 837 838DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 839 "-soundhw c1,... enable audio support\n" 840 " and only specified sound cards (comma separated list)\n" 841 " use '-soundhw help' to get the list of supported cards\n" 842 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 843SRST 844``-soundhw card1[,card2,...] or -soundhw all`` 845 Enable audio and selected sound hardware. Use 'help' to print all 846 available sound hardware. For example: 847 848 .. parsed-literal:: 849 850 |qemu_system_x86| -soundhw sb16,adlib disk.img 851 |qemu_system_x86| -soundhw es1370 disk.img 852 |qemu_system_x86| -soundhw ac97 disk.img 853 |qemu_system_x86| -soundhw hda disk.img 854 |qemu_system_x86| -soundhw all disk.img 855 |qemu_system_x86| -soundhw help 856 857 Note that Linux's i810\_audio OSS kernel (for AC97) module might 858 require manually specifying clocking. 859 860 :: 861 862 modprobe i810_audio clocking=48000 863ERST 864 865DEF("device", HAS_ARG, QEMU_OPTION_device, 866 "-device driver[,prop[=value][,...]]\n" 867 " add device (based on driver)\n" 868 " prop=value,... sets driver properties\n" 869 " use '-device help' to print all possible drivers\n" 870 " use '-device driver,help' to print all possible properties\n", 871 QEMU_ARCH_ALL) 872SRST 873``-device driver[,prop[=value][,...]]`` 874 Add device driver. prop=value sets driver properties. Valid 875 properties depend on the driver. To get help on possible drivers and 876 properties, use ``-device help`` and ``-device driver,help``. 877 878 Some drivers are: 879 880``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 881 Add an IPMI BMC. This is a simulation of a hardware management 882 interface processor that normally sits on a system. It provides a 883 watchdog and the ability to reset and power control the system. You 884 need to connect this to an IPMI interface to make it useful 885 886 The IPMI slave address to use for the BMC. The default is 0x20. This 887 address is the BMC's address on the I2C network of management 888 controllers. If you don't know what this means, it is safe to ignore 889 it. 890 891 ``id=id`` 892 The BMC id for interfaces to use this device. 893 894 ``slave_addr=val`` 895 Define slave address to use for the BMC. The default is 0x20. 896 897 ``sdrfile=file`` 898 file containing raw Sensor Data Records (SDR) data. The default 899 is none. 900 901 ``fruareasize=val`` 902 size of a Field Replaceable Unit (FRU) area. The default is 903 1024. 904 905 ``frudatafile=file`` 906 file containing raw Field Replaceable Unit (FRU) inventory data. 907 The default is none. 908 909 ``guid=uuid`` 910 value for the GUID for the BMC, in standard UUID format. If this 911 is set, get "Get GUID" command to the BMC will return it. 912 Otherwise "Get GUID" will return an error. 913 914``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 915 Add a connection to an external IPMI BMC simulator. Instead of 916 locally emulating the BMC like the above item, instead connect to an 917 external entity that provides the IPMI services. 918 919 A connection is made to an external BMC simulator. If you do this, 920 it is strongly recommended that you use the "reconnect=" chardev 921 option to reconnect to the simulator if the connection is lost. Note 922 that if this is not used carefully, it can be a security issue, as 923 the interface has the ability to send resets, NMIs, and power off 924 the VM. It's best if QEMU makes a connection to an external 925 simulator running on a secure port on localhost, so neither the 926 simulator nor QEMU is exposed to any outside network. 927 928 See the "lanserv/README.vm" file in the OpenIPMI library for more 929 details on the external interface. 930 931``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 932 Add a KCS IPMI interafce on the ISA bus. This also adds a 933 corresponding ACPI and SMBIOS entries, if appropriate. 934 935 ``bmc=id`` 936 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 937 above. 938 939 ``ioport=val`` 940 Define the I/O address of the interface. The default is 0xca0 941 for KCS. 942 943 ``irq=val`` 944 Define the interrupt to use. The default is 5. To disable 945 interrupts, set this to 0. 946 947``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 948 Like the KCS interface, but defines a BT interface. The default port 949 is 0xe4 and the default interrupt is 5. 950 951``-device pci-ipmi-kcs,bmc=id`` 952 Add a KCS IPMI interafce on the PCI bus. 953 954 ``bmc=id`` 955 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 956 957``-device pci-ipmi-bt,bmc=id`` 958 Like the KCS interface, but defines a BT interface on the PCI bus. 959 960``-device intel-iommu[,option=...]`` 961 This is only supported by ``-machine q35``, which will enable Intel VT-d 962 emulation within the guest. It supports below options: 963 964 ``intremap=on|off`` (default: auto) 965 This enables interrupt remapping feature. It's required to enable 966 complete x2apic. Currently it only supports kvm kernel-irqchip modes 967 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 968 The default value is "auto", which will be decided by the mode of 969 kernel-irqchip. 970 971 ``caching-mode=on|off`` (default: off) 972 This enables caching mode for the VT-d emulated device. When 973 caching-mode is enabled, each guest DMA buffer mapping will generate an 974 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 975 a synchronous way. It is required for ``-device vfio-pci`` to work 976 with the VT-d device, because host assigned devices requires to setup 977 the DMA mapping on the host before guest DMA starts. 978 979 ``device-iotlb=on|off`` (default: off) 980 This enables device-iotlb capability for the emulated VT-d device. So 981 far virtio/vhost should be the only real user for this parameter, 982 paired with ats=on configured for the device. 983 984 ``aw-bits=39|48`` (default: 39) 985 This decides the address width of IOVA address space. The address 986 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 987 4-level IOMMU page tables. 988 989 Please also refer to the wiki page for general scenarios of VT-d 990 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 991 992ERST 993 994DEF("name", HAS_ARG, QEMU_OPTION_name, 995 "-name string1[,process=string2][,debug-threads=on|off]\n" 996 " set the name of the guest\n" 997 " string1 sets the window title and string2 the process name\n" 998 " When debug-threads is enabled, individual threads are given a separate name\n" 999 " NOTE: The thread names are for debugging and not a stable API.\n", 1000 QEMU_ARCH_ALL) 1001SRST 1002``-name name`` 1003 Sets the name of the guest. This name will be displayed in the SDL 1004 window caption. The name will also be used for the VNC server. Also 1005 optionally set the top visible process name in Linux. Naming of 1006 individual threads can also be enabled on Linux to aid debugging. 1007ERST 1008 1009DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1010 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1011 " specify machine UUID\n", QEMU_ARCH_ALL) 1012SRST 1013``-uuid uuid`` 1014 Set system UUID. 1015ERST 1016 1017DEFHEADING() 1018 1019DEFHEADING(Block device options:) 1020 1021DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1022 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1023DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1024SRST 1025``-fda file`` 1026 \ 1027``-fdb file`` 1028 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1029 the System Emulation Users Guide). 1030ERST 1031 1032DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1033 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1034DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1035DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1036 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1037DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1038SRST 1039``-hda file`` 1040 \ 1041``-hdb file`` 1042 \ 1043``-hdc file`` 1044 \ 1045``-hdd file`` 1046 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1047 chapter in the System Emulation Users Guide). 1048ERST 1049 1050DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1051 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1052 QEMU_ARCH_ALL) 1053SRST 1054``-cdrom file`` 1055 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1056 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1057 as filename. 1058ERST 1059 1060DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1061 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1062 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1063 " [,read-only=on|off][,auto-read-only=on|off]\n" 1064 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1065 " [,driver specific parameters...]\n" 1066 " configure a block backend\n", QEMU_ARCH_ALL) 1067SRST 1068``-blockdev option[,option[,option[,...]]]`` 1069 Define a new block driver node. Some of the options apply to all 1070 block drivers, other options are only accepted for a specific block 1071 driver. See below for a list of generic options and options for the 1072 most common block drivers. 1073 1074 Options that expect a reference to another node (e.g. ``file``) can 1075 be given in two ways. Either you specify the node name of an already 1076 existing node (file=node-name), or you define a new node inline, 1077 adding options for the referenced node after a dot 1078 (file.filename=path,file.aio=native). 1079 1080 A block driver node created with ``-blockdev`` can be used for a 1081 guest device by specifying its node name for the ``drive`` property 1082 in a ``-device`` argument that defines a block device. 1083 1084 ``Valid options for any block driver node:`` 1085 ``driver`` 1086 Specifies the block driver to use for the given node. 1087 1088 ``node-name`` 1089 This defines the name of the block driver node by which it 1090 will be referenced later. The name must be unique, i.e. it 1091 must not match the name of a different block driver node, or 1092 (if you use ``-drive`` as well) the ID of a drive. 1093 1094 If no node name is specified, it is automatically generated. 1095 The generated node name is not intended to be predictable 1096 and changes between QEMU invocations. For the top level, an 1097 explicit node name must be specified. 1098 1099 ``read-only`` 1100 Open the node read-only. Guest write attempts will fail. 1101 1102 Note that some block drivers support only read-only access, 1103 either generally or in certain configurations. In this case, 1104 the default value ``read-only=off`` does not work and the 1105 option must be specified explicitly. 1106 1107 ``auto-read-only`` 1108 If ``auto-read-only=on`` is set, QEMU may fall back to 1109 read-only usage even when ``read-only=off`` is requested, or 1110 even switch between modes as needed, e.g. depending on 1111 whether the image file is writable or whether a writing user 1112 is attached to the node. 1113 1114 ``force-share`` 1115 Override the image locking system of QEMU by forcing the 1116 node to utilize weaker shared access for permissions where 1117 it would normally request exclusive access. When there is 1118 the potential for multiple instances to have the same file 1119 open (whether this invocation of QEMU is the first or the 1120 second instance), both instances must permit shared access 1121 for the second instance to succeed at opening the file. 1122 1123 Enabling ``force-share=on`` requires ``read-only=on``. 1124 1125 ``cache.direct`` 1126 The host page cache can be avoided with ``cache.direct=on``. 1127 This will attempt to do disk IO directly to the guest's 1128 memory. QEMU may still perform an internal copy of the data. 1129 1130 ``cache.no-flush`` 1131 In case you don't care about data integrity over host 1132 failures, you can use ``cache.no-flush=on``. This option 1133 tells QEMU that it never needs to write any data to the disk 1134 but can instead keep things in cache. If anything goes 1135 wrong, like your host losing power, the disk storage getting 1136 disconnected accidentally, etc. your image will most 1137 probably be rendered unusable. 1138 1139 ``discard=discard`` 1140 discard is one of "ignore" (or "off") or "unmap" (or "on") 1141 and controls whether ``discard`` (also known as ``trim`` or 1142 ``unmap``) requests are ignored or passed to the filesystem. 1143 Some machine types may not support discard requests. 1144 1145 ``detect-zeroes=detect-zeroes`` 1146 detect-zeroes is "off", "on" or "unmap" and enables the 1147 automatic conversion of plain zero writes by the OS to 1148 driver specific optimized zero write commands. You may even 1149 choose "unmap" if discard is set to "unmap" to allow a zero 1150 write to be converted to an ``unmap`` operation. 1151 1152 ``Driver-specific options for file`` 1153 This is the protocol-level block driver for accessing regular 1154 files. 1155 1156 ``filename`` 1157 The path to the image file in the local filesystem 1158 1159 ``aio`` 1160 Specifies the AIO backend (threads/native/io_uring, 1161 default: threads) 1162 1163 ``locking`` 1164 Specifies whether the image file is protected with Linux OFD 1165 / POSIX locks. The default is to use the Linux Open File 1166 Descriptor API if available, otherwise no lock is applied. 1167 (auto/on/off, default: auto) 1168 1169 Example: 1170 1171 :: 1172 1173 -blockdev driver=file,node-name=disk,filename=disk.img 1174 1175 ``Driver-specific options for raw`` 1176 This is the image format block driver for raw images. It is 1177 usually stacked on top of a protocol level block driver such as 1178 ``file``. 1179 1180 ``file`` 1181 Reference to or definition of the data source block driver 1182 node (e.g. a ``file`` driver node) 1183 1184 Example 1: 1185 1186 :: 1187 1188 -blockdev driver=file,node-name=disk_file,filename=disk.img 1189 -blockdev driver=raw,node-name=disk,file=disk_file 1190 1191 Example 2: 1192 1193 :: 1194 1195 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1196 1197 ``Driver-specific options for qcow2`` 1198 This is the image format block driver for qcow2 images. It is 1199 usually stacked on top of a protocol level block driver such as 1200 ``file``. 1201 1202 ``file`` 1203 Reference to or definition of the data source block driver 1204 node (e.g. a ``file`` driver node) 1205 1206 ``backing`` 1207 Reference to or definition of the backing file block device 1208 (default is taken from the image file). It is allowed to 1209 pass ``null`` here in order to disable the default backing 1210 file. 1211 1212 ``lazy-refcounts`` 1213 Whether to enable the lazy refcounts feature (on/off; 1214 default is taken from the image file) 1215 1216 ``cache-size`` 1217 The maximum total size of the L2 table and refcount block 1218 caches in bytes (default: the sum of l2-cache-size and 1219 refcount-cache-size) 1220 1221 ``l2-cache-size`` 1222 The maximum size of the L2 table cache in bytes (default: if 1223 cache-size is not specified - 32M on Linux platforms, and 8M 1224 on non-Linux platforms; otherwise, as large as possible 1225 within the cache-size, while permitting the requested or the 1226 minimal refcount cache size) 1227 1228 ``refcount-cache-size`` 1229 The maximum size of the refcount block cache in bytes 1230 (default: 4 times the cluster size; or if cache-size is 1231 specified, the part of it which is not used for the L2 1232 cache) 1233 1234 ``cache-clean-interval`` 1235 Clean unused entries in the L2 and refcount caches. The 1236 interval is in seconds. The default value is 600 on 1237 supporting platforms, and 0 on other platforms. Setting it 1238 to 0 disables this feature. 1239 1240 ``pass-discard-request`` 1241 Whether discard requests to the qcow2 device should be 1242 forwarded to the data source (on/off; default: on if 1243 discard=unmap is specified, off otherwise) 1244 1245 ``pass-discard-snapshot`` 1246 Whether discard requests for the data source should be 1247 issued when a snapshot operation (e.g. deleting a snapshot) 1248 frees clusters in the qcow2 file (on/off; default: on) 1249 1250 ``pass-discard-other`` 1251 Whether discard requests for the data source should be 1252 issued on other occasions where a cluster gets freed 1253 (on/off; default: off) 1254 1255 ``overlap-check`` 1256 Which overlap checks to perform for writes to the image 1257 (none/constant/cached/all; default: cached). For details or 1258 finer granularity control refer to the QAPI documentation of 1259 ``blockdev-add``. 1260 1261 Example 1: 1262 1263 :: 1264 1265 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1266 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1267 1268 Example 2: 1269 1270 :: 1271 1272 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1273 1274 ``Driver-specific options for other drivers`` 1275 Please refer to the QAPI documentation of the ``blockdev-add`` 1276 QMP command. 1277ERST 1278 1279DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1280 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1281 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1282 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1283 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1284 " [,aio=threads|native|io_uring]\n" 1285 " [,readonly=on|off][,copy-on-read=on|off]\n" 1286 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1287 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1288 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1289 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1290 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1291 " [[,iops_size=is]]\n" 1292 " [[,group=g]]\n" 1293 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1294SRST 1295``-drive option[,option[,option[,...]]]`` 1296 Define a new drive. This includes creating a block driver node (the 1297 backend) as well as a guest device, and is mostly a shortcut for 1298 defining the corresponding ``-blockdev`` and ``-device`` options. 1299 1300 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1301 In addition, it knows the following options: 1302 1303 ``file=file`` 1304 This option defines which disk image (see the :ref:`disk images` 1305 chapter in the System Emulation Users Guide) to use with this drive. 1306 If the filename contains comma, you must double it (for instance, 1307 "file=my,,file" to use file "my,file"). 1308 1309 Special files such as iSCSI devices can be specified using 1310 protocol specific URLs. See the section for "Device URL Syntax" 1311 for more information. 1312 1313 ``if=interface`` 1314 This option defines on which type on interface the drive is 1315 connected. Available types are: ide, scsi, sd, mtd, floppy, 1316 pflash, virtio, none. 1317 1318 ``bus=bus,unit=unit`` 1319 These options define where is connected the drive by defining 1320 the bus number and the unit id. 1321 1322 ``index=index`` 1323 This option defines where is connected the drive by using an 1324 index in the list of available connectors of a given interface 1325 type. 1326 1327 ``media=media`` 1328 This option defines the type of the media: disk or cdrom. 1329 1330 ``snapshot=snapshot`` 1331 snapshot is "on" or "off" and controls snapshot mode for the 1332 given drive (see ``-snapshot``). 1333 1334 ``cache=cache`` 1335 cache is "none", "writeback", "unsafe", "directsync" or 1336 "writethrough" and controls how the host cache is used to access 1337 block data. This is a shortcut that sets the ``cache.direct`` 1338 and ``cache.no-flush`` options (as in ``-blockdev``), and 1339 additionally ``cache.writeback``, which provides a default for 1340 the ``write-cache`` option of block guest devices (as in 1341 ``-device``). The modes correspond to the following settings: 1342 1343 ============= =============== ============ ============== 1344 \ cache.writeback cache.direct cache.no-flush 1345 ============= =============== ============ ============== 1346 writeback on off off 1347 none on on off 1348 writethrough off off off 1349 directsync off on off 1350 unsafe on off on 1351 ============= =============== ============ ============== 1352 1353 The default mode is ``cache=writeback``. 1354 1355 ``aio=aio`` 1356 aio is "threads", "native", or "io_uring" and selects between pthread 1357 based disk I/O, native Linux AIO, or Linux io_uring API. 1358 1359 ``format=format`` 1360 Specify which disk format will be used rather than detecting the 1361 format. Can be used to specify format=raw to avoid interpreting 1362 an untrusted format header. 1363 1364 ``werror=action,rerror=action`` 1365 Specify which action to take on write and read errors. Valid 1366 actions are: "ignore" (ignore the error and try to continue), 1367 "stop" (pause QEMU), "report" (report the error to the guest), 1368 "enospc" (pause QEMU only if the host disk is full; report the 1369 error to the guest otherwise). The default setting is 1370 ``werror=enospc`` and ``rerror=report``. 1371 1372 ``copy-on-read=copy-on-read`` 1373 copy-on-read is "on" or "off" and enables whether to copy read 1374 backing file sectors into the image file. 1375 1376 ``bps=b,bps_rd=r,bps_wr=w`` 1377 Specify bandwidth throttling limits in bytes per second, either 1378 for all request types or for reads or writes only. Small values 1379 can lead to timeouts or hangs inside the guest. A safe minimum 1380 for disks is 2 MB/s. 1381 1382 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1383 Specify bursts in bytes per second, either for all request types 1384 or for reads or writes only. Bursts allow the guest I/O to spike 1385 above the limit temporarily. 1386 1387 ``iops=i,iops_rd=r,iops_wr=w`` 1388 Specify request rate limits in requests per second, either for 1389 all request types or for reads or writes only. 1390 1391 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1392 Specify bursts in requests per second, either for all request 1393 types or for reads or writes only. Bursts allow the guest I/O to 1394 spike above the limit temporarily. 1395 1396 ``iops_size=is`` 1397 Let every is bytes of a request count as a new request for iops 1398 throttling purposes. Use this option to prevent guests from 1399 circumventing iops limits by sending fewer but larger requests. 1400 1401 ``group=g`` 1402 Join a throttling quota group with given name g. All drives that 1403 are members of the same group are accounted for together. Use 1404 this option to prevent guests from circumventing throttling 1405 limits by using many small disks instead of a single larger 1406 disk. 1407 1408 By default, the ``cache.writeback=on`` mode is used. It will report 1409 data writes as completed as soon as the data is present in the host 1410 page cache. This is safe as long as your guest OS makes sure to 1411 correctly flush disk caches where needed. If your guest OS does not 1412 handle volatile disk write caches correctly and your host crashes or 1413 loses power, then the guest may experience data corruption. 1414 1415 For such guests, you should consider using ``cache.writeback=off``. 1416 This means that the host page cache will be used to read and write 1417 data, but write notification will be sent to the guest only after 1418 QEMU has made sure to flush each write to the disk. Be aware that 1419 this has a major impact on performance. 1420 1421 When using the ``-snapshot`` option, unsafe caching is always used. 1422 1423 Copy-on-read avoids accessing the same backing file sectors 1424 repeatedly and is useful when the backing file is over a slow 1425 network. By default copy-on-read is off. 1426 1427 Instead of ``-cdrom`` you can use: 1428 1429 .. parsed-literal:: 1430 1431 |qemu_system| -drive file=file,index=2,media=cdrom 1432 1433 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1434 1435 .. parsed-literal:: 1436 1437 |qemu_system| -drive file=file,index=0,media=disk 1438 |qemu_system| -drive file=file,index=1,media=disk 1439 |qemu_system| -drive file=file,index=2,media=disk 1440 |qemu_system| -drive file=file,index=3,media=disk 1441 1442 You can open an image using pre-opened file descriptors from an fd 1443 set: 1444 1445 .. parsed-literal:: 1446 1447 |qemu_system| \\ 1448 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1449 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1450 -drive file=/dev/fdset/2,index=0,media=disk 1451 1452 You can connect a CDROM to the slave of ide0: 1453 1454 .. parsed-literal:: 1455 1456 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1457 1458 If you don't specify the "file=" argument, you define an empty 1459 drive: 1460 1461 .. parsed-literal:: 1462 1463 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1464 1465 Instead of ``-fda``, ``-fdb``, you can use: 1466 1467 .. parsed-literal:: 1468 1469 |qemu_system_x86| -drive file=file,index=0,if=floppy 1470 |qemu_system_x86| -drive file=file,index=1,if=floppy 1471 1472 By default, interface is "ide" and index is automatically 1473 incremented: 1474 1475 .. parsed-literal:: 1476 1477 |qemu_system_x86| -drive file=a -drive file=b" 1478 1479 is interpreted like: 1480 1481 .. parsed-literal:: 1482 1483 |qemu_system_x86| -hda a -hdb b 1484ERST 1485 1486DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1487 "-mtdblock file use 'file' as on-board Flash memory image\n", 1488 QEMU_ARCH_ALL) 1489SRST 1490``-mtdblock file`` 1491 Use file as on-board Flash memory image. 1492ERST 1493 1494DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1495 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1496SRST 1497``-sd file`` 1498 Use file as SecureDigital card image. 1499ERST 1500 1501DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1502 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1503SRST 1504``-pflash file`` 1505 Use file as a parallel flash image. 1506ERST 1507 1508DEF("snapshot", 0, QEMU_OPTION_snapshot, 1509 "-snapshot write to temporary files instead of disk image files\n", 1510 QEMU_ARCH_ALL) 1511SRST 1512``-snapshot`` 1513 Write to temporary files instead of disk image files. In this case, 1514 the raw disk image you use is not written back. You can however 1515 force the write back by pressing C-a s (see the :ref:`disk images` 1516 chapter in the System Emulation Users Guide). 1517ERST 1518 1519DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1520 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1521 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1522 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1523 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1524 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1525 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1526 " [[,throttling.iops-size=is]]\n" 1527 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1528 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1529 "-fsdev synth,id=id\n", 1530 QEMU_ARCH_ALL) 1531 1532SRST 1533``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1534 \ 1535``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1536 \ 1537``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1538 \ 1539``-fsdev synth,id=id[,readonly=on]`` 1540 Define a new file system device. Valid options are: 1541 1542 ``local`` 1543 Accesses to the filesystem are done by QEMU. 1544 1545 ``proxy`` 1546 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1547 1548 ``synth`` 1549 Synthetic filesystem, only used by QTests. 1550 1551 ``id=id`` 1552 Specifies identifier for this device. 1553 1554 ``path=path`` 1555 Specifies the export path for the file system device. Files 1556 under this path will be available to the 9p client on the guest. 1557 1558 ``security_model=security_model`` 1559 Specifies the security model to be used for this export path. 1560 Supported security models are "passthrough", "mapped-xattr", 1561 "mapped-file" and "none". In "passthrough" security model, files 1562 are stored using the same credentials as they are created on the 1563 guest. This requires QEMU to run as root. In "mapped-xattr" 1564 security model, some of the file attributes like uid, gid, mode 1565 bits and link target are stored as file attributes. For 1566 "mapped-file" these attributes are stored in the hidden 1567 .virtfs\_metadata directory. Directories exported by this 1568 security model cannot interact with other unix tools. "none" 1569 security model is same as passthrough except the sever won't 1570 report failures if it fails to set file attributes like 1571 ownership. Security model is mandatory only for local fsdriver. 1572 Other fsdrivers (like proxy) don't take security model as a 1573 parameter. 1574 1575 ``writeout=writeout`` 1576 This is an optional argument. The only supported value is 1577 "immediate". This means that host page cache will be used to 1578 read and write data but write notification will be sent to the 1579 guest only when the data has been reported as written by the 1580 storage subsystem. 1581 1582 ``readonly=on`` 1583 Enables exporting 9p share as a readonly mount for guests. By 1584 default read-write access is given. 1585 1586 ``socket=socket`` 1587 Enables proxy filesystem driver to use passed socket file for 1588 communicating with virtfs-proxy-helper(1). 1589 1590 ``sock_fd=sock_fd`` 1591 Enables proxy filesystem driver to use passed socket descriptor 1592 for communicating with virtfs-proxy-helper(1). Usually a helper 1593 like libvirt will create socketpair and pass one of the fds as 1594 sock\_fd. 1595 1596 ``fmode=fmode`` 1597 Specifies the default mode for newly created files on the host. 1598 Works only with security models "mapped-xattr" and 1599 "mapped-file". 1600 1601 ``dmode=dmode`` 1602 Specifies the default mode for newly created directories on the 1603 host. Works only with security models "mapped-xattr" and 1604 "mapped-file". 1605 1606 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1607 Specify bandwidth throttling limits in bytes per second, either 1608 for all request types or for reads or writes only. 1609 1610 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1611 Specify bursts in bytes per second, either for all request types 1612 or for reads or writes only. Bursts allow the guest I/O to spike 1613 above the limit temporarily. 1614 1615 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1616 Specify request rate limits in requests per second, either for 1617 all request types or for reads or writes only. 1618 1619 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1620 Specify bursts in requests per second, either for all request 1621 types or for reads or writes only. Bursts allow the guest I/O to 1622 spike above the limit temporarily. 1623 1624 ``throttling.iops-size=is`` 1625 Let every is bytes of a request count as a new request for iops 1626 throttling purposes. 1627 1628 -fsdev option is used along with -device driver "virtio-9p-...". 1629 1630``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1631 Options for virtio-9p-... driver are: 1632 1633 ``type`` 1634 Specifies the variant to be used. Supported values are "pci", 1635 "ccw" or "device", depending on the machine type. 1636 1637 ``fsdev=id`` 1638 Specifies the id value specified along with -fsdev option. 1639 1640 ``mount_tag=mount_tag`` 1641 Specifies the tag name to be used by the guest to mount this 1642 export point. 1643ERST 1644 1645DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1646 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1647 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1648 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1649 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1650 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1651 QEMU_ARCH_ALL) 1652 1653SRST 1654``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1655 \ 1656``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1657 \ 1658``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1659 \ 1660``-virtfs synth,mount_tag=mount_tag`` 1661 Define a new virtual filesystem device and expose it to the guest using 1662 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1663 directory on host is made directly accessible by guest as a pass-through 1664 file system by using the 9P network protocol for communication between 1665 host and guests, if desired even accessible, shared by several guests 1666 simultaniously. 1667 1668 Note that ``-virtfs`` is actually just a convenience shortcut for its 1669 generalized form ``-fsdev -device virtio-9p-pci``. 1670 1671 The general form of pass-through file system options are: 1672 1673 ``local`` 1674 Accesses to the filesystem are done by QEMU. 1675 1676 ``proxy`` 1677 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1678 1679 ``synth`` 1680 Synthetic filesystem, only used by QTests. 1681 1682 ``id=id`` 1683 Specifies identifier for the filesystem device 1684 1685 ``path=path`` 1686 Specifies the export path for the file system device. Files 1687 under this path will be available to the 9p client on the guest. 1688 1689 ``security_model=security_model`` 1690 Specifies the security model to be used for this export path. 1691 Supported security models are "passthrough", "mapped-xattr", 1692 "mapped-file" and "none". In "passthrough" security model, files 1693 are stored using the same credentials as they are created on the 1694 guest. This requires QEMU to run as root. In "mapped-xattr" 1695 security model, some of the file attributes like uid, gid, mode 1696 bits and link target are stored as file attributes. For 1697 "mapped-file" these attributes are stored in the hidden 1698 .virtfs\_metadata directory. Directories exported by this 1699 security model cannot interact with other unix tools. "none" 1700 security model is same as passthrough except the sever won't 1701 report failures if it fails to set file attributes like 1702 ownership. Security model is mandatory only for local fsdriver. 1703 Other fsdrivers (like proxy) don't take security model as a 1704 parameter. 1705 1706 ``writeout=writeout`` 1707 This is an optional argument. The only supported value is 1708 "immediate". This means that host page cache will be used to 1709 read and write data but write notification will be sent to the 1710 guest only when the data has been reported as written by the 1711 storage subsystem. 1712 1713 ``readonly=on`` 1714 Enables exporting 9p share as a readonly mount for guests. By 1715 default read-write access is given. 1716 1717 ``socket=socket`` 1718 Enables proxy filesystem driver to use passed socket file for 1719 communicating with virtfs-proxy-helper(1). Usually a helper like 1720 libvirt will create socketpair and pass one of the fds as 1721 sock\_fd. 1722 1723 ``sock_fd`` 1724 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1725 socket descriptor for interfacing with virtfs-proxy-helper(1). 1726 1727 ``fmode=fmode`` 1728 Specifies the default mode for newly created files on the host. 1729 Works only with security models "mapped-xattr" and 1730 "mapped-file". 1731 1732 ``dmode=dmode`` 1733 Specifies the default mode for newly created directories on the 1734 host. Works only with security models "mapped-xattr" and 1735 "mapped-file". 1736 1737 ``mount_tag=mount_tag`` 1738 Specifies the tag name to be used by the guest to mount this 1739 export point. 1740 1741 ``multidevs=multidevs`` 1742 Specifies how to deal with multiple devices being shared with a 1743 9p export. Supported behaviours are either "remap", "forbid" or 1744 "warn". The latter is the default behaviour on which virtfs 9p 1745 expects only one device to be shared with the same export, and 1746 if more than one device is shared and accessed via the same 9p 1747 export then only a warning message is logged (once) by qemu on 1748 host side. In order to avoid file ID collisions on guest you 1749 should either create a separate virtfs export for each device to 1750 be shared with guests (recommended way) or you might use "remap" 1751 instead which allows you to share multiple devices with only one 1752 export instead, which is achieved by remapping the original 1753 inode numbers from host to guest in a way that would prevent 1754 such collisions. Remapping inodes in such use cases is required 1755 because the original device IDs from host are never passed and 1756 exposed on guest. Instead all files of an export shared with 1757 virtfs always share the same device id on guest. So two files 1758 with identical inode numbers but from actually different devices 1759 on host would otherwise cause a file ID collision and hence 1760 potential misbehaviours on guest. "forbid" on the other hand 1761 assumes like "warn" that only one device is shared by the same 1762 export, however it will not only log a warning message but also 1763 deny access to additional devices on guest. Note though that 1764 "forbid" does currently not block all possible file access 1765 operations (e.g. readdir() would still return entries from other 1766 devices). 1767ERST 1768 1769DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1770 "-iscsi [user=user][,password=password]\n" 1771 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1772 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1773 " [,timeout=timeout]\n" 1774 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1775 1776SRST 1777``-iscsi`` 1778 Configure iSCSI session parameters. 1779ERST 1780 1781DEFHEADING() 1782 1783DEFHEADING(USB convenience options:) 1784 1785DEF("usb", 0, QEMU_OPTION_usb, 1786 "-usb enable on-board USB host controller (if not enabled by default)\n", 1787 QEMU_ARCH_ALL) 1788SRST 1789``-usb`` 1790 Enable USB emulation on machine types with an on-board USB host 1791 controller (if not enabled by default). Note that on-board USB host 1792 controllers may not support USB 3.0. In this case 1793 ``-device qemu-xhci`` can be used instead on machines with PCI. 1794ERST 1795 1796DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1797 "-usbdevice name add the host or guest USB device 'name'\n", 1798 QEMU_ARCH_ALL) 1799SRST 1800``-usbdevice devname`` 1801 Add the USB device devname, and enable an on-board USB controller 1802 if possible and necessary (just like it can be done via 1803 ``-machine usb=on``). Note that this option is mainly intended for 1804 the user's convenience only. More fine-grained control can be 1805 achieved by selecting a USB host controller (if necessary) and the 1806 desired USB device via the ``-device`` option instead. For example, 1807 instead of using ``-usbdevice mouse`` it is possible to use 1808 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1809 to a USB 3.0 controller instead (at least on machines that support 1810 PCI and do not have an USB controller enabled by default yet). 1811 For more details, see the chapter about 1812 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1813 Possible devices for devname are: 1814 1815 ``braille`` 1816 Braille device. This will use BrlAPI to display the braille 1817 output on a real or fake device (i.e. it also creates a 1818 corresponding ``braille`` chardev automatically beside the 1819 ``usb-braille`` USB device). 1820 1821 ``keyboard`` 1822 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1823 1824 ``mouse`` 1825 Virtual Mouse. This will override the PS/2 mouse emulation when 1826 activated. 1827 1828 ``tablet`` 1829 Pointer device that uses absolute coordinates (like a 1830 touchscreen). This means QEMU is able to report the mouse 1831 position without having to grab the mouse. Also overrides the 1832 PS/2 mouse emulation when activated. 1833 1834 ``wacom-tablet`` 1835 Wacom PenPartner USB tablet. 1836 1837 1838ERST 1839 1840DEFHEADING() 1841 1842DEFHEADING(Display options:) 1843 1844DEF("display", HAS_ARG, QEMU_OPTION_display, 1845#if defined(CONFIG_SPICE) 1846 "-display spice-app[,gl=on|off]\n" 1847#endif 1848#if defined(CONFIG_SDL) 1849 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1850 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n" 1851#endif 1852#if defined(CONFIG_GTK) 1853 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1854 " [,show-cursor=on|off][,window-close=on|off]\n" 1855#endif 1856#if defined(CONFIG_VNC) 1857 "-display vnc=<display>[,<optargs>]\n" 1858#endif 1859#if defined(CONFIG_CURSES) 1860 "-display curses[,charset=<encoding>]\n" 1861#endif 1862#if defined(CONFIG_OPENGL) 1863 "-display egl-headless[,rendernode=<file>]\n" 1864#endif 1865 "-display none\n" 1866 " select display backend type\n" 1867 " The default display is equivalent to\n " 1868#if defined(CONFIG_GTK) 1869 "\"-display gtk\"\n" 1870#elif defined(CONFIG_SDL) 1871 "\"-display sdl\"\n" 1872#elif defined(CONFIG_COCOA) 1873 "\"-display cocoa\"\n" 1874#elif defined(CONFIG_VNC) 1875 "\"-vnc localhost:0,to=99,id=default\"\n" 1876#else 1877 "\"-display none\"\n" 1878#endif 1879 , QEMU_ARCH_ALL) 1880SRST 1881``-display type`` 1882 Select type of display to use. This option is a replacement for the 1883 old style -sdl/-curses/... options. Use ``-display help`` to list 1884 the available display types. Valid values for type are 1885 1886 ``spice-app[,gl=on|off]`` 1887 Start QEMU as a Spice server and launch the default Spice client 1888 application. The Spice server will redirect the serial consoles 1889 and QEMU monitors. (Since 4.0) 1890 1891 ``sdl`` 1892 Display video output via SDL (usually in a separate graphics 1893 window; see the SDL documentation for other possibilities). 1894 Valid parameters are: 1895 1896 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 1897 the mouse grabbing in conjunction with the "g" key. `<mods>` can be 1898 either `lshift-lctrl-lalt` or `rctrl`. 1899 1900 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing. 1901 This parameter is deprecated - use ``grab-mod`` instead. 1902 1903 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing. 1904 This parameter is deprecated - use ``grab-mod`` instead. 1905 1906 ``gl=on|off|core|es`` : Use OpenGL for displaying 1907 1908 ``show-cursor=on|off`` : Force showing the mouse cursor 1909 1910 ``window-close=on|off`` : Allow to quit qemu with window close button 1911 1912 ``gtk`` 1913 Display video output in a GTK window. This interface provides 1914 drop-down menus and other UI elements to configure and control 1915 the VM during runtime. Valid parameters are: 1916 1917 ``full-screen=on|off`` : Start in fullscreen mode 1918 1919 ``gl=on|off`` : Use OpenGL for displaying 1920 1921 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 1922 1923 ``show-cursor=on|off`` : Force showing the mouse cursor 1924 1925 ``window-close=on|off`` : Allow to quit qemu with window close button 1926 1927 ``curses[,charset=<encoding>]`` 1928 Display video output via curses. For graphics device models 1929 which support a text mode, QEMU can display this output using a 1930 curses/ncurses interface. Nothing is displayed when the graphics 1931 device is in graphical mode or if the graphics device does not 1932 support a text mode. Generally only the VGA device models 1933 support text mode. The font charset used by the guest can be 1934 specified with the ``charset`` option, for example 1935 ``charset=CP850`` for IBM CP850 encoding. The default is 1936 ``CP437``. 1937 1938 ``egl-headless[,rendernode=<file>]`` 1939 Offload all OpenGL operations to a local DRI device. For any 1940 graphical display, this display needs to be paired with either 1941 VNC or SPICE displays. 1942 1943 ``vnc=<display>`` 1944 Start a VNC server on display <display> 1945 1946 ``none`` 1947 Do not display video output. The guest will still see an 1948 emulated graphics card, but its output will not be displayed to 1949 the QEMU user. This option differs from the -nographic option in 1950 that it only affects what is done with video output; -nographic 1951 also changes the destination of the serial and parallel port 1952 data. 1953ERST 1954 1955DEF("nographic", 0, QEMU_OPTION_nographic, 1956 "-nographic disable graphical output and redirect serial I/Os to console\n", 1957 QEMU_ARCH_ALL) 1958SRST 1959``-nographic`` 1960 Normally, if QEMU is compiled with graphical window support, it 1961 displays output such as guest graphics, guest console, and the QEMU 1962 monitor in a window. With this option, you can totally disable 1963 graphical output so that QEMU is a simple command line application. 1964 The emulated serial port is redirected on the console and muxed with 1965 the monitor (unless redirected elsewhere explicitly). Therefore, you 1966 can still use QEMU to debug a Linux kernel with a serial console. 1967 Use C-a h for help on switching between the console and monitor. 1968ERST 1969 1970DEF("curses", 0, QEMU_OPTION_curses, 1971 "-curses shorthand for -display curses\n", 1972 QEMU_ARCH_ALL) 1973SRST 1974``-curses`` 1975 Normally, if QEMU is compiled with graphical window support, it 1976 displays output such as guest graphics, guest console, and the QEMU 1977 monitor in a window. With this option, QEMU can display the VGA 1978 output when in text mode using a curses/ncurses interface. Nothing 1979 is displayed in graphical mode. 1980ERST 1981 1982DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1983 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1984 QEMU_ARCH_ALL) 1985SRST 1986``-alt-grab`` 1987 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1988 this also affects the special keys (for fullscreen, monitor-mode 1989 switching, etc). This option is deprecated - please use 1990 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead. 1991ERST 1992 1993DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1994 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1995 QEMU_ARCH_ALL) 1996SRST 1997``-ctrl-grab`` 1998 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1999 also affects the special keys (for fullscreen, monitor-mode 2000 switching, etc). This option is deprecated - please use 2001 ``-display sdl,grab-mod=rctrl`` instead. 2002ERST 2003 2004DEF("no-quit", 0, QEMU_OPTION_no_quit, 2005 "-no-quit disable SDL/GTK window close capability (deprecated)\n", QEMU_ARCH_ALL) 2006SRST 2007``-no-quit`` 2008 Disable window close capability (SDL and GTK only). This option is 2009 deprecated, please use ``-display ...,window-close=off`` instead. 2010ERST 2011 2012DEF("sdl", 0, QEMU_OPTION_sdl, 2013 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 2014SRST 2015``-sdl`` 2016 Enable SDL. 2017ERST 2018 2019DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2020 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2021 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2022 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2023 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2024 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2025 " [,tls-ciphers=<list>]\n" 2026 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2027 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2028 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2029 " [,password=<string>][,password-secret=<secret-id>]\n" 2030 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2031 " [,jpeg-wan-compression=[auto|never|always]]\n" 2032 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2033 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2034 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2035 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2036 " [,gl=[on|off]][,rendernode=<file>]\n" 2037 " enable spice\n" 2038 " at least one of {port, tls-port} is mandatory\n", 2039 QEMU_ARCH_ALL) 2040SRST 2041``-spice option[,option[,...]]`` 2042 Enable the spice remote desktop protocol. Valid options are 2043 2044 ``port=<nr>`` 2045 Set the TCP port spice is listening on for plaintext channels. 2046 2047 ``addr=<addr>`` 2048 Set the IP address spice is listening on. Default is any 2049 address. 2050 2051 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2052 Force using the specified IP version. 2053 2054 ``password=<string>`` 2055 Set the password you need to authenticate. 2056 2057 This option is deprecated and insecure because it leaves the 2058 password visible in the process listing. Use ``password-secret`` 2059 instead. 2060 2061 ``password-secret=<secret-id>`` 2062 Set the ID of the ``secret`` object containing the password 2063 you need to authenticate. 2064 2065 ``sasl=on|off`` 2066 Require that the client use SASL to authenticate with the spice. 2067 The exact choice of authentication method used is controlled 2068 from the system / user's SASL configuration file for the 'qemu' 2069 service. This is typically found in /etc/sasl2/qemu.conf. If 2070 running QEMU as an unprivileged user, an environment variable 2071 SASL\_CONF\_PATH can be used to make it search alternate 2072 locations for the service config. While some SASL auth methods 2073 can also provide data encryption (eg GSSAPI), it is recommended 2074 that SASL always be combined with the 'tls' and 'x509' settings 2075 to enable use of SSL and server certificates. This ensures a 2076 data encryption preventing compromise of authentication 2077 credentials. 2078 2079 ``disable-ticketing=on|off`` 2080 Allow client connects without authentication. 2081 2082 ``disable-copy-paste=on|off`` 2083 Disable copy paste between the client and the guest. 2084 2085 ``disable-agent-file-xfer=on|off`` 2086 Disable spice-vdagent based file-xfer between the client and the 2087 guest. 2088 2089 ``tls-port=<nr>`` 2090 Set the TCP port spice is listening on for encrypted channels. 2091 2092 ``x509-dir=<dir>`` 2093 Set the x509 file directory. Expects same filenames as -vnc 2094 $display,x509=$dir 2095 2096 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2097 The x509 file names can also be configured individually. 2098 2099 ``tls-ciphers=<list>`` 2100 Specify which ciphers to use. 2101 2102 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2103 Force specific channel to be used with or without TLS 2104 encryption. The options can be specified multiple times to 2105 configure multiple channels. The special name "default" can be 2106 used to set the default mode. For channels which are not 2107 explicitly forced into one mode the spice client is allowed to 2108 pick tls/plaintext as he pleases. 2109 2110 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2111 Configure image compression (lossless). Default is auto\_glz. 2112 2113 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2114 Configure wan image compression (lossy for slow links). Default 2115 is auto. 2116 2117 ``streaming-video=[off|all|filter]`` 2118 Configure video stream detection. Default is off. 2119 2120 ``agent-mouse=[on|off]`` 2121 Enable/disable passing mouse events via vdagent. Default is on. 2122 2123 ``playback-compression=[on|off]`` 2124 Enable/disable audio stream compression (using celt 0.5.1). 2125 Default is on. 2126 2127 ``seamless-migration=[on|off]`` 2128 Enable/disable spice seamless migration. Default is off. 2129 2130 ``gl=[on|off]`` 2131 Enable/disable OpenGL context. Default is off. 2132 2133 ``rendernode=<file>`` 2134 DRM render node for OpenGL rendering. If not specified, it will 2135 pick the first available. (Since 2.9) 2136ERST 2137 2138DEF("portrait", 0, QEMU_OPTION_portrait, 2139 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2140 QEMU_ARCH_ALL) 2141SRST 2142``-portrait`` 2143 Rotate graphical output 90 deg left (only PXA LCD). 2144ERST 2145 2146DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2147 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2148 QEMU_ARCH_ALL) 2149SRST 2150``-rotate deg`` 2151 Rotate graphical output some deg left (only PXA LCD). 2152ERST 2153 2154DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2155 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2156 " select video card type\n", QEMU_ARCH_ALL) 2157SRST 2158``-vga type`` 2159 Select type of VGA card to emulate. Valid values for type are 2160 2161 ``cirrus`` 2162 Cirrus Logic GD5446 Video card. All Windows versions starting 2163 from Windows 95 should recognize and use this graphic card. For 2164 optimal performances, use 16 bit color depth in the guest and 2165 the host OS. (This card was the default before QEMU 2.2) 2166 2167 ``std`` 2168 Standard VGA card with Bochs VBE extensions. If your guest OS 2169 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2170 you want to use high resolution modes (>= 1280x1024x16) then you 2171 should use this option. (This card is the default since QEMU 2172 2.2) 2173 2174 ``vmware`` 2175 VMWare SVGA-II compatible adapter. Use it if you have 2176 sufficiently recent XFree86/XOrg server or Windows guest with a 2177 driver for this card. 2178 2179 ``qxl`` 2180 QXL paravirtual graphic card. It is VGA compatible (including 2181 VESA 2.0 VBE support). Works best with qxl guest drivers 2182 installed though. Recommended choice when using the spice 2183 protocol. 2184 2185 ``tcx`` 2186 (sun4m only) Sun TCX framebuffer. This is the default 2187 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2188 colour depths at a fixed resolution of 1024x768. 2189 2190 ``cg3`` 2191 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2192 framebuffer for sun4m machines available in both 1024x768 2193 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2194 wishing to run older Solaris versions. 2195 2196 ``virtio`` 2197 Virtio VGA card. 2198 2199 ``none`` 2200 Disable VGA card. 2201ERST 2202 2203DEF("full-screen", 0, QEMU_OPTION_full_screen, 2204 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2205SRST 2206``-full-screen`` 2207 Start in full screen. 2208ERST 2209 2210DEF("g", HAS_ARG, QEMU_OPTION_g , 2211 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2212 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2213SRST 2214``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2215 Set the initial graphical resolution and depth (PPC, SPARC only). 2216 2217 For PPC the default is 800x600x32. 2218 2219 For SPARC with the TCX graphics device, the default is 1024x768x8 2220 with the option of 1024x768x24. For cgthree, the default is 2221 1024x768x8 with the option of 1152x900x8 for people who wish to use 2222 OBP. 2223ERST 2224 2225DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2226 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2227SRST 2228``-vnc display[,option[,option[,...]]]`` 2229 Normally, if QEMU is compiled with graphical window support, it 2230 displays output such as guest graphics, guest console, and the QEMU 2231 monitor in a window. With this option, you can have QEMU listen on 2232 VNC display display and redirect the VGA display over the VNC 2233 session. It is very useful to enable the usb tablet device when 2234 using this option (option ``-device usb-tablet``). When using the 2235 VNC display, you must use the ``-k`` parameter to set the keyboard 2236 layout if you are not using en-us. Valid syntax for the display is 2237 2238 ``to=L`` 2239 With this option, QEMU will try next available VNC displays, 2240 until the number L, if the origianlly defined "-vnc display" is 2241 not available, e.g. port 5900+display is already used by another 2242 application. By default, to=0. 2243 2244 ``host:d`` 2245 TCP connections will only be allowed from host on display d. By 2246 convention the TCP port is 5900+d. Optionally, host can be 2247 omitted in which case the server will accept connections from 2248 any host. 2249 2250 ``unix:path`` 2251 Connections will be allowed over UNIX domain sockets where path 2252 is the location of a unix socket to listen for connections on. 2253 2254 ``none`` 2255 VNC is initialized but not started. The monitor ``change`` 2256 command can be used to later start the VNC server. 2257 2258 Following the display value there may be one or more option flags 2259 separated by commas. Valid options are 2260 2261 ``reverse=on|off`` 2262 Connect to a listening VNC client via a "reverse" connection. 2263 The client is specified by the display. For reverse network 2264 connections (host:d,``reverse``), the d argument is a TCP port 2265 number, not a display number. 2266 2267 ``websocket=on|off`` 2268 Opens an additional TCP listening port dedicated to VNC 2269 Websocket connections. If a bare websocket option is given, the 2270 Websocket port is 5700+display. An alternative port can be 2271 specified with the syntax ``websocket``\ =port. 2272 2273 If host is specified connections will only be allowed from this 2274 host. It is possible to control the websocket listen address 2275 independently, using the syntax ``websocket``\ =host:port. 2276 2277 If no TLS credentials are provided, the websocket connection 2278 runs in unencrypted mode. If TLS credentials are provided, the 2279 websocket connection requires encrypted client connections. 2280 2281 ``password=on|off`` 2282 Require that password based authentication is used for client 2283 connections. 2284 2285 The password must be set separately using the ``set_password`` 2286 command in the :ref:`QEMU monitor`. The 2287 syntax to change your password is: 2288 ``set_password <protocol> <password>`` where <protocol> could be 2289 either "vnc" or "spice". 2290 2291 If you would like to change <protocol> password expiration, you 2292 should use ``expire_password <protocol> <expiration-time>`` 2293 where expiration time could be one of the following options: 2294 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2295 make password expire in 60 seconds, or 1335196800 to make 2296 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2297 this date and time). 2298 2299 You can also use keywords "now" or "never" for the expiration 2300 time to allow <protocol> password to expire immediately or never 2301 expire. 2302 2303 ``password-secret=<secret-id>`` 2304 Require that password based authentication is used for client 2305 connections, using the password provided by the ``secret`` 2306 object identified by ``secret-id``. 2307 2308 ``tls-creds=ID`` 2309 Provides the ID of a set of TLS credentials to use to secure the 2310 VNC server. They will apply to both the normal VNC server socket 2311 and the websocket socket (if enabled). Setting TLS credentials 2312 will cause the VNC server socket to enable the VeNCrypt auth 2313 mechanism. The credentials should have been previously created 2314 using the ``-object tls-creds`` argument. 2315 2316 ``tls-authz=ID`` 2317 Provides the ID of the QAuthZ authorization object against which 2318 the client's x509 distinguished name will validated. This object 2319 is only resolved at time of use, so can be deleted and recreated 2320 on the fly while the VNC server is active. If missing, it will 2321 default to denying access. 2322 2323 ``sasl=on|off`` 2324 Require that the client use SASL to authenticate with the VNC 2325 server. The exact choice of authentication method used is 2326 controlled from the system / user's SASL configuration file for 2327 the 'qemu' service. This is typically found in 2328 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2329 an environment variable SASL\_CONF\_PATH can be used to make it 2330 search alternate locations for the service config. While some 2331 SASL auth methods can also provide data encryption (eg GSSAPI), 2332 it is recommended that SASL always be combined with the 'tls' 2333 and 'x509' settings to enable use of SSL and server 2334 certificates. This ensures a data encryption preventing 2335 compromise of authentication credentials. See the 2336 :ref:`VNC security` section in the System Emulation Users Guide 2337 for details on using SASL authentication. 2338 2339 ``sasl-authz=ID`` 2340 Provides the ID of the QAuthZ authorization object against which 2341 the client's SASL username will validated. This object is only 2342 resolved at time of use, so can be deleted and recreated on the 2343 fly while the VNC server is active. If missing, it will default 2344 to denying access. 2345 2346 ``acl=on|off`` 2347 Legacy method for enabling authorization of clients against the 2348 x509 distinguished name and SASL username. It results in the 2349 creation of two ``authz-list`` objects with IDs of 2350 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2351 objects must be configured with the HMP ACL commands. 2352 2353 This option is deprecated and should no longer be used. The new 2354 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2355 2356 ``lossy=on|off`` 2357 Enable lossy compression methods (gradient, JPEG, ...). If this 2358 option is set, VNC client may receive lossy framebuffer updates 2359 depending on its encoding settings. Enabling this option can 2360 save a lot of bandwidth at the expense of quality. 2361 2362 ``non-adaptive=on|off`` 2363 Disable adaptive encodings. Adaptive encodings are enabled by 2364 default. An adaptive encoding will try to detect frequently 2365 updated screen regions, and send updates in these regions using 2366 a lossy encoding (like JPEG). This can be really helpful to save 2367 bandwidth when playing videos. Disabling adaptive encodings 2368 restores the original static behavior of encodings like Tight. 2369 2370 ``share=[allow-exclusive|force-shared|ignore]`` 2371 Set display sharing policy. 'allow-exclusive' allows clients to 2372 ask for exclusive access. As suggested by the rfb spec this is 2373 implemented by dropping other connections. Connecting multiple 2374 clients in parallel requires all clients asking for a shared 2375 session (vncviewer: -shared switch). This is the default. 2376 'force-shared' disables exclusive client access. Useful for 2377 shared desktop sessions, where you don't want someone forgetting 2378 specify -shared disconnect everybody else. 'ignore' completely 2379 ignores the shared flag and allows everybody connect 2380 unconditionally. Doesn't conform to the rfb spec but is 2381 traditional QEMU behavior. 2382 2383 ``key-delay-ms`` 2384 Set keyboard delay, for key down and key up events, in 2385 milliseconds. Default is 10. Keyboards are low-bandwidth 2386 devices, so this slowdown can help the device and guest to keep 2387 up and not lose events in case events are arriving in bulk. 2388 Possible causes for the latter are flaky network connections, or 2389 scripts for automated testing. 2390 2391 ``audiodev=audiodev`` 2392 Use the specified audiodev when the VNC client requests audio 2393 transmission. When not using an -audiodev argument, this option 2394 must be omitted, otherwise is must be present and specify a 2395 valid audiodev. 2396 2397 ``power-control=on|off`` 2398 Permit the remote client to issue shutdown, reboot or reset power 2399 control requests. 2400ERST 2401 2402ARCHHEADING(, QEMU_ARCH_I386) 2403 2404ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2405 2406DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2407 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2408 QEMU_ARCH_I386) 2409SRST 2410``-win2k-hack`` 2411 Use it when installing Windows 2000 to avoid a disk full bug. After 2412 Windows 2000 is installed, you no longer need this option (this 2413 option slows down the IDE transfers). 2414ERST 2415 2416DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2417 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2418 QEMU_ARCH_I386) 2419SRST 2420``-no-fd-bootchk`` 2421 Disable boot signature checking for floppy disks in BIOS. May be 2422 needed to boot from old floppy disks. 2423ERST 2424 2425DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2426 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2427SRST 2428``-no-acpi`` 2429 Disable ACPI (Advanced Configuration and Power Interface) support. 2430 Use it if your guest OS complains about ACPI problems (PC target 2431 machine only). 2432ERST 2433 2434DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2435 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2436SRST 2437``-no-hpet`` 2438 Disable HPET support. 2439ERST 2440 2441DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2442 "-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" 2443 " ACPI table description\n", QEMU_ARCH_I386) 2444SRST 2445``-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]...]`` 2446 Add ACPI table with specified header fields and context from 2447 specified files. For file=, take whole ACPI table from the specified 2448 files, including all ACPI headers (possible overridden by other 2449 options). For data=, only data portion of the table is used, all 2450 header information is specified in the command line. If a SLIC table 2451 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2452 fields will override the same in the RSDT and the FADT (a.k.a. 2453 FACP), in order to ensure the field matches required by the 2454 Microsoft SLIC spec and the ACPI spec. 2455ERST 2456 2457DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2458 "-smbios file=binary\n" 2459 " load SMBIOS entry from binary file\n" 2460 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2461 " [,uefi=on|off]\n" 2462 " specify SMBIOS type 0 fields\n" 2463 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2464 " [,uuid=uuid][,sku=str][,family=str]\n" 2465 " specify SMBIOS type 1 fields\n" 2466 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2467 " [,asset=str][,location=str]\n" 2468 " specify SMBIOS type 2 fields\n" 2469 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2470 " [,sku=str]\n" 2471 " specify SMBIOS type 3 fields\n" 2472 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2473 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2474 " specify SMBIOS type 4 fields\n" 2475 "-smbios type=11[,value=str][,path=filename]\n" 2476 " specify SMBIOS type 11 fields\n" 2477 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2478 " [,asset=str][,part=str][,speed=%d]\n" 2479 " specify SMBIOS type 17 fields\n" 2480 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2481 " specify SMBIOS type 41 fields\n", 2482 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2483SRST 2484``-smbios file=binary`` 2485 Load SMBIOS entry from binary file. 2486 2487``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2488 Specify SMBIOS type 0 fields 2489 2490``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2491 Specify SMBIOS type 1 fields 2492 2493``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2494 Specify SMBIOS type 2 fields 2495 2496``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2497 Specify SMBIOS type 3 fields 2498 2499``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2500 Specify SMBIOS type 4 fields 2501 2502``-smbios type=11[,value=str][,path=filename]`` 2503 Specify SMBIOS type 11 fields 2504 2505 This argument can be repeated multiple times, and values are added in the order they are parsed. 2506 Applications intending to use OEM strings data are encouraged to use their application name as 2507 a prefix for the value string. This facilitates passing information for multiple applications 2508 concurrently. 2509 2510 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2511 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2512 2513 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2514 the SMBIOS table in the order in which they appear. 2515 2516 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2517 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2518 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2519 data set, for example, by specifying the serial ID of a block device. 2520 2521 An example passing three strings is 2522 2523 .. parsed-literal:: 2524 2525 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2526 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2527 path=/some/file/with/oemstringsdata.txt 2528 2529 In the guest OS this is visible with the ``dmidecode`` command 2530 2531 .. parsed-literal:: 2532 2533 $ dmidecode -t 11 2534 Handle 0x0E00, DMI type 11, 5 bytes 2535 OEM Strings 2536 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2537 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2538 String 3: myapp:some extra data 2539 2540 2541``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2542 Specify SMBIOS type 17 fields 2543 2544``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2545 Specify SMBIOS type 41 fields 2546 2547 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2548 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2549 position on the PCI bus. 2550 2551 Here is an example of use: 2552 2553 .. parsed-literal:: 2554 2555 -netdev user,id=internet \\ 2556 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2557 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2558 2559 In the guest OS, the device should then appear as ``eno1``: 2560 2561 ..parsed-literal:: 2562 2563 $ ip -brief l 2564 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2565 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2566 2567 Currently, the PCI device has to be attached to the root bus. 2568 2569ERST 2570 2571DEFHEADING() 2572 2573DEFHEADING(Network options:) 2574 2575DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2576#ifdef CONFIG_SLIRP 2577 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2578 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2579 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2580 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2581 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2582#ifndef _WIN32 2583 "[,smb=dir[,smbserver=addr]]\n" 2584#endif 2585 " configure a user mode network backend with ID 'str',\n" 2586 " its DHCP server and optional services\n" 2587#endif 2588#ifdef _WIN32 2589 "-netdev tap,id=str,ifname=name\n" 2590 " configure a host TAP network backend with ID 'str'\n" 2591#else 2592 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2593 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2594 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2595 " [,poll-us=n]\n" 2596 " configure a host TAP network backend with ID 'str'\n" 2597 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2598 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2599 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2600 " to deconfigure it\n" 2601 " use '[down]script=no' to disable script execution\n" 2602 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2603 " configure it\n" 2604 " use 'fd=h' to connect to an already opened TAP interface\n" 2605 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2606 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2607 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2608 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2609 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2610 " use vhost=on to enable experimental in kernel accelerator\n" 2611 " (only has effect for virtio guests which use MSIX)\n" 2612 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2613 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2614 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2615 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2616 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2617 " spent on busy polling for vhost net\n" 2618 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2619 " configure a host TAP network backend with ID 'str' that is\n" 2620 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2621 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2622#endif 2623#ifdef __linux__ 2624 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2625 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2626 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2627 " [,rxcookie=rxcookie][,offset=offset]\n" 2628 " configure a network backend with ID 'str' connected to\n" 2629 " an Ethernet over L2TPv3 pseudowire.\n" 2630 " Linux kernel 3.3+ as well as most routers can talk\n" 2631 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2632 " VM to a router and even VM to Host. It is a nearly-universal\n" 2633 " standard (RFC3931). Note - this implementation uses static\n" 2634 " pre-configured tunnels (same as the Linux kernel).\n" 2635 " use 'src=' to specify source address\n" 2636 " use 'dst=' to specify destination address\n" 2637 " use 'udp=on' to specify udp encapsulation\n" 2638 " use 'srcport=' to specify source udp port\n" 2639 " use 'dstport=' to specify destination udp port\n" 2640 " use 'ipv6=on' to force v6\n" 2641 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2642 " well as a weak security measure\n" 2643 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2644 " use 'txcookie=0x012345678' to specify a txcookie\n" 2645 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2646 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2647 " use 'pincounter=on' to work around broken counter handling in peer\n" 2648 " use 'offset=X' to add an extra offset between header and data\n" 2649#endif 2650 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2651 " configure a network backend to connect to another network\n" 2652 " using a socket connection\n" 2653 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2654 " configure a network backend to connect to a multicast maddr and port\n" 2655 " use 'localaddr=addr' to specify the host address to send packets from\n" 2656 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2657 " configure a network backend to connect to another network\n" 2658 " using an UDP tunnel\n" 2659#ifdef CONFIG_VDE 2660 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2661 " configure a network backend to connect to port 'n' of a vde switch\n" 2662 " running on host and listening for incoming connections on 'socketpath'.\n" 2663 " Use group 'groupname' and mode 'octalmode' to change default\n" 2664 " ownership and permissions for communication port.\n" 2665#endif 2666#ifdef CONFIG_NETMAP 2667 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2668 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2669 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2670 " netmap device, defaults to '/dev/netmap')\n" 2671#endif 2672#ifdef CONFIG_POSIX 2673 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2674 " configure a vhost-user network, backed by a chardev 'dev'\n" 2675#endif 2676#ifdef __linux__ 2677 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2678 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2679#endif 2680 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2681 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2682DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2683 "-nic [tap|bridge|" 2684#ifdef CONFIG_SLIRP 2685 "user|" 2686#endif 2687#ifdef __linux__ 2688 "l2tpv3|" 2689#endif 2690#ifdef CONFIG_VDE 2691 "vde|" 2692#endif 2693#ifdef CONFIG_NETMAP 2694 "netmap|" 2695#endif 2696#ifdef CONFIG_POSIX 2697 "vhost-user|" 2698#endif 2699 "socket][,option][,...][mac=macaddr]\n" 2700 " initialize an on-board / default host NIC (using MAC address\n" 2701 " macaddr) and connect it to the given host network backend\n" 2702 "-nic none use it alone to have zero network devices (the default is to\n" 2703 " provided a 'user' network connection)\n", 2704 QEMU_ARCH_ALL) 2705DEF("net", HAS_ARG, QEMU_OPTION_net, 2706 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2707 " configure or create an on-board (or machine default) NIC and\n" 2708 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2709 "-net [" 2710#ifdef CONFIG_SLIRP 2711 "user|" 2712#endif 2713 "tap|" 2714 "bridge|" 2715#ifdef CONFIG_VDE 2716 "vde|" 2717#endif 2718#ifdef CONFIG_NETMAP 2719 "netmap|" 2720#endif 2721 "socket][,option][,option][,...]\n" 2722 " old way to initialize a host network interface\n" 2723 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2724SRST 2725``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2726 This option is a shortcut for configuring both the on-board 2727 (default) guest NIC hardware and the host network backend in one go. 2728 The host backend options are the same as with the corresponding 2729 ``-netdev`` options below. The guest NIC model can be set with 2730 ``model=modelname``. Use ``model=help`` to list the available device 2731 types. The hardware MAC address can be set with ``mac=macaddr``. 2732 2733 The following two example do exactly the same, to show how ``-nic`` 2734 can be used to shorten the command line length: 2735 2736 .. parsed-literal:: 2737 2738 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2739 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2740 2741``-nic none`` 2742 Indicate that no network devices should be configured. It is used to 2743 override the default configuration (default NIC with "user" host 2744 network backend) which is activated if no other networking options 2745 are provided. 2746 2747``-netdev user,id=id[,option][,option][,...]`` 2748 Configure user mode host network backend which requires no 2749 administrator privilege to run. Valid options are: 2750 2751 ``id=id`` 2752 Assign symbolic name for use in monitor commands. 2753 2754 ``ipv4=on|off and ipv6=on|off`` 2755 Specify that either IPv4 or IPv6 must be enabled. If neither is 2756 specified both protocols are enabled. 2757 2758 ``net=addr[/mask]`` 2759 Set IP network address the guest will see. Optionally specify 2760 the netmask, either in the form a.b.c.d or as number of valid 2761 top-most bits. Default is 10.0.2.0/24. 2762 2763 ``host=addr`` 2764 Specify the guest-visible address of the host. Default is the 2765 2nd IP in the guest network, i.e. x.x.x.2. 2766 2767 ``ipv6-net=addr[/int]`` 2768 Set IPv6 network address the guest will see (default is 2769 fec0::/64). The network prefix is given in the usual hexadecimal 2770 IPv6 address notation. The prefix size is optional, and is given 2771 as the number of valid top-most bits (default is 64). 2772 2773 ``ipv6-host=addr`` 2774 Specify the guest-visible IPv6 address of the host. Default is 2775 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2776 2777 ``restrict=on|off`` 2778 If this option is enabled, the guest will be isolated, i.e. it 2779 will not be able to contact the host and no guest IP packets 2780 will be routed over the host to the outside. This option does 2781 not affect any explicitly set forwarding rules. 2782 2783 ``hostname=name`` 2784 Specifies the client hostname reported by the built-in DHCP 2785 server. 2786 2787 ``dhcpstart=addr`` 2788 Specify the first of the 16 IPs the built-in DHCP server can 2789 assign. Default is the 15th to 31st IP in the guest network, 2790 i.e. x.x.x.15 to x.x.x.31. 2791 2792 ``dns=addr`` 2793 Specify the guest-visible address of the virtual nameserver. The 2794 address must be different from the host address. Default is the 2795 3rd IP in the guest network, i.e. x.x.x.3. 2796 2797 ``ipv6-dns=addr`` 2798 Specify the guest-visible address of the IPv6 virtual 2799 nameserver. The address must be different from the host address. 2800 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2801 2802 ``dnssearch=domain`` 2803 Provides an entry for the domain-search list sent by the 2804 built-in DHCP server. More than one domain suffix can be 2805 transmitted by specifying this option multiple times. If 2806 supported, this will cause the guest to automatically try to 2807 append the given domain suffix(es) in case a domain name can not 2808 be resolved. 2809 2810 Example: 2811 2812 .. parsed-literal:: 2813 2814 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2815 2816 ``domainname=domain`` 2817 Specifies the client domain name reported by the built-in DHCP 2818 server. 2819 2820 ``tftp=dir`` 2821 When using the user mode network stack, activate a built-in TFTP 2822 server. The files in dir will be exposed as the root of a TFTP 2823 server. The TFTP client on the guest must be configured in 2824 binary mode (use the command ``bin`` of the Unix TFTP client). 2825 2826 ``tftp-server-name=name`` 2827 In BOOTP reply, broadcast name as the "TFTP server name" 2828 (RFC2132 option 66). This can be used to advise the guest to 2829 load boot files or configurations from a different server than 2830 the host address. 2831 2832 ``bootfile=file`` 2833 When using the user mode network stack, broadcast file as the 2834 BOOTP filename. In conjunction with ``tftp``, this can be used 2835 to network boot a guest from a local directory. 2836 2837 Example (using pxelinux): 2838 2839 .. parsed-literal:: 2840 2841 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2842 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2843 2844 ``smb=dir[,smbserver=addr]`` 2845 When using the user mode network stack, activate a built-in SMB 2846 server so that Windows OSes can access to the host files in 2847 ``dir`` transparently. The IP address of the SMB server can be 2848 set to addr. By default the 4th IP in the guest network is used, 2849 i.e. x.x.x.4. 2850 2851 In the guest Windows OS, the line: 2852 2853 :: 2854 2855 10.0.2.4 smbserver 2856 2857 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2858 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2859 NT/2000). 2860 2861 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2862 2863 Note that a SAMBA server must be installed on the host OS. 2864 2865 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2866 Redirect incoming TCP or UDP connections to the host port 2867 hostport to the guest IP address guestaddr on guest port 2868 guestport. If guestaddr is not specified, its value is x.x.x.15 2869 (default first address given by the built-in DHCP server). By 2870 specifying hostaddr, the rule can be bound to a specific host 2871 interface. If no connection type is set, TCP is used. This 2872 option can be given multiple times. 2873 2874 For example, to redirect host X11 connection from screen 1 to 2875 guest screen 0, use the following: 2876 2877 .. parsed-literal:: 2878 2879 # on the host 2880 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2881 # this host xterm should open in the guest X11 server 2882 xterm -display :1 2883 2884 To redirect telnet connections from host port 5555 to telnet 2885 port on the guest, use the following: 2886 2887 .. parsed-literal:: 2888 2889 # on the host 2890 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2891 telnet localhost 5555 2892 2893 Then when you use on the host ``telnet localhost 5555``, you 2894 connect to the guest telnet server. 2895 2896 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2897 Forward guest TCP connections to the IP address server on port 2898 port to the character device dev or to a program executed by 2899 cmd:command which gets spawned for each connection. This option 2900 can be given multiple times. 2901 2902 You can either use a chardev directly and have that one used 2903 throughout QEMU's lifetime, like in the following example: 2904 2905 .. parsed-literal:: 2906 2907 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2908 # the guest accesses it 2909 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2910 2911 Or you can execute a command on every TCP connection established 2912 by the guest, so that QEMU behaves similar to an inetd process 2913 for that virtual server: 2914 2915 .. parsed-literal:: 2916 2917 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2918 # and connect the TCP stream to its stdin/stdout 2919 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2920 2921``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2922 Configure a host TAP network backend with ID id. 2923 2924 Use the network script file to configure it and the network script 2925 dfile to deconfigure it. If name is not provided, the OS 2926 automatically provides one. The default network configure script is 2927 ``/etc/qemu-ifup`` and the default network deconfigure script is 2928 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2929 disable script execution. 2930 2931 If running QEMU as an unprivileged user, use the network helper 2932 to configure the TAP interface and attach it to the bridge. 2933 The default network helper executable is 2934 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2935 ``br0``. 2936 2937 ``fd``\ =h can be used to specify the handle of an already opened 2938 host TAP interface. 2939 2940 Examples: 2941 2942 .. parsed-literal:: 2943 2944 #launch a QEMU instance with the default network script 2945 |qemu_system| linux.img -nic tap 2946 2947 .. parsed-literal:: 2948 2949 #launch a QEMU instance with two NICs, each one connected 2950 #to a TAP device 2951 |qemu_system| linux.img \\ 2952 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2953 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2954 2955 .. parsed-literal:: 2956 2957 #launch a QEMU instance with the default network helper to 2958 #connect a TAP device to bridge br0 2959 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2960 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2961 2962``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2963 Connect a host TAP network interface to a host bridge device. 2964 2965 Use the network helper helper to configure the TAP interface and 2966 attach it to the bridge. The default network helper executable is 2967 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2968 ``br0``. 2969 2970 Examples: 2971 2972 .. parsed-literal:: 2973 2974 #launch a QEMU instance with the default network helper to 2975 #connect a TAP device to bridge br0 2976 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2977 2978 .. parsed-literal:: 2979 2980 #launch a QEMU instance with the default network helper to 2981 #connect a TAP device to bridge qemubr0 2982 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2983 2984``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2985 This host network backend can be used to connect the guest's network 2986 to another QEMU virtual machine using a TCP socket connection. If 2987 ``listen`` is specified, QEMU waits for incoming connections on port 2988 (host is optional). ``connect`` is used to connect to another QEMU 2989 instance using the ``listen`` option. ``fd``\ =h specifies an 2990 already opened TCP socket. 2991 2992 Example: 2993 2994 .. parsed-literal:: 2995 2996 # launch a first QEMU instance 2997 |qemu_system| linux.img \\ 2998 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2999 -netdev socket,id=n1,listen=:1234 3000 # connect the network of this instance to the network of the first instance 3001 |qemu_system| linux.img \\ 3002 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3003 -netdev socket,id=n2,connect=127.0.0.1:1234 3004 3005``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3006 Configure a socket host network backend to share the guest's network 3007 traffic with another QEMU virtual machines using a UDP multicast 3008 socket, effectively making a bus for every QEMU with same multicast 3009 address maddr and port. NOTES: 3010 3011 1. Several QEMU can be running on different hosts and share same bus 3012 (assuming correct multicast setup for these hosts). 3013 3014 2. mcast support is compatible with User Mode Linux (argument 3015 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3016 3017 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3018 3019 Example: 3020 3021 .. parsed-literal:: 3022 3023 # launch one QEMU instance 3024 |qemu_system| linux.img \\ 3025 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3026 -netdev socket,id=n1,mcast=230.0.0.1:1234 3027 # launch another QEMU instance on same "bus" 3028 |qemu_system| linux.img \\ 3029 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3030 -netdev socket,id=n2,mcast=230.0.0.1:1234 3031 # launch yet another QEMU instance on same "bus" 3032 |qemu_system| linux.img \\ 3033 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3034 -netdev socket,id=n3,mcast=230.0.0.1:1234 3035 3036 Example (User Mode Linux compat.): 3037 3038 .. parsed-literal:: 3039 3040 # launch QEMU instance (note mcast address selected is UML's default) 3041 |qemu_system| linux.img \\ 3042 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3043 -netdev socket,id=n1,mcast=239.192.168.1:1102 3044 # launch UML 3045 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3046 3047 Example (send packets from host's 1.2.3.4): 3048 3049 .. parsed-literal:: 3050 3051 |qemu_system| linux.img \\ 3052 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3053 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3054 3055``-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]`` 3056 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3057 is a popular protocol to transport Ethernet (and other Layer 2) data 3058 frames between two systems. It is present in routers, firewalls and 3059 the Linux kernel (from version 3.3 onwards). 3060 3061 This transport allows a VM to communicate to another VM, router or 3062 firewall directly. 3063 3064 ``src=srcaddr`` 3065 source address (mandatory) 3066 3067 ``dst=dstaddr`` 3068 destination address (mandatory) 3069 3070 ``udp`` 3071 select udp encapsulation (default is ip). 3072 3073 ``srcport=srcport`` 3074 source udp port. 3075 3076 ``dstport=dstport`` 3077 destination udp port. 3078 3079 ``ipv6`` 3080 force v6, otherwise defaults to v4. 3081 3082 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3083 Cookies are a weak form of security in the l2tpv3 specification. 3084 Their function is mostly to prevent misconfiguration. By default 3085 they are 32 bit. 3086 3087 ``cookie64`` 3088 Set cookie size to 64 bit instead of the default 32 3089 3090 ``counter=off`` 3091 Force a 'cut-down' L2TPv3 with no counter as in 3092 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3093 3094 ``pincounter=on`` 3095 Work around broken counter handling in peer. This may also help 3096 on networks which have packet reorder. 3097 3098 ``offset=offset`` 3099 Add an extra offset between header and data 3100 3101 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3102 the bridge br-lan on the remote Linux host 1.2.3.4: 3103 3104 .. parsed-literal:: 3105 3106 # Setup tunnel on linux host using raw ip as encapsulation 3107 # on 1.2.3.4 3108 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3109 encap udp udp_sport 16384 udp_dport 16384 3110 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3111 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3112 ifconfig vmtunnel0 mtu 1500 3113 ifconfig vmtunnel0 up 3114 brctl addif br-lan vmtunnel0 3115 3116 3117 # on 4.3.2.1 3118 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3119 3120 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3121 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3122 3123``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3124 Configure VDE backend to connect to PORT n of a vde switch running 3125 on host and listening for incoming connections on socketpath. Use 3126 GROUP groupname and MODE octalmode to change default ownership and 3127 permissions for communication port. This option is only available if 3128 QEMU has been compiled with vde support enabled. 3129 3130 Example: 3131 3132 .. parsed-literal:: 3133 3134 # launch vde switch 3135 vde_switch -F -sock /tmp/myswitch 3136 # launch QEMU instance 3137 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3138 3139``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3140 Establish a vhost-user netdev, backed by a chardev id. The chardev 3141 should be a unix domain socket backed one. The vhost-user uses a 3142 specifically defined protocol to pass vhost ioctl replacement 3143 messages to an application on the other end of the socket. On 3144 non-MSIX guests, the feature can be forced with vhostforce. Use 3145 'queues=n' to specify the number of queues to be created for 3146 multiqueue vhost-user. 3147 3148 Example: 3149 3150 :: 3151 3152 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3153 -numa node,memdev=mem \ 3154 -chardev socket,id=chr0,path=/path/to/socket \ 3155 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3156 -device virtio-net-pci,netdev=net0 3157 3158``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3159 Establish a vhost-vdpa netdev. 3160 3161 vDPA device is a device that uses a datapath which complies with 3162 the virtio specifications with a vendor specific control path. 3163 vDPA devices can be both physically located on the hardware or 3164 emulated by software. 3165 3166``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3167 Create a hub port on the emulated hub with ID hubid. 3168 3169 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3170 instead of a single netdev. Alternatively, you can also connect the 3171 hubport to another netdev with ID nd by using the ``netdev=nd`` 3172 option. 3173 3174``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3175 Legacy option to configure or create an on-board (or machine 3176 default) Network Interface Card(NIC) and connect it either to the 3177 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3178 If model is omitted, then the default NIC model associated with the 3179 machine type is used. Note that the default NIC model may change in 3180 future QEMU releases, so it is highly recommended to always specify 3181 a model. Optionally, the MAC address can be changed to mac, the 3182 device address set to addr (PCI cards only), and a name can be 3183 assigned for use in monitor commands. Optionally, for PCI cards, you 3184 can specify the number v of MSI-X vectors that the card should have; 3185 this option currently only affects virtio cards; set v = 0 to 3186 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3187 created. QEMU can emulate several different models of network card. 3188 Use ``-net nic,model=help`` for a list of available devices for your 3189 target. 3190 3191``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3192 Configure a host network backend (with the options corresponding to 3193 the same ``-netdev`` option) and connect it to the emulated hub 0 3194 (the default hub). Use name to specify the name of the hub port. 3195ERST 3196 3197DEFHEADING() 3198 3199DEFHEADING(Character device options:) 3200 3201DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3202 "-chardev help\n" 3203 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3204 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3205 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3206 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3207 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3208 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3209 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3210 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3211 " [,logfile=PATH][,logappend=on|off]\n" 3212 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3213 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3214 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3215 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3216 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3217 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3218#ifdef _WIN32 3219 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3220 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3221#else 3222 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3223 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3224#endif 3225#ifdef CONFIG_BRLAPI 3226 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3227#endif 3228#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3229 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3230 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3231 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3232#endif 3233#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3234 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3235 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3236#endif 3237#if defined(CONFIG_SPICE) 3238 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3239 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3240#endif 3241 , QEMU_ARCH_ALL 3242) 3243 3244SRST 3245The general form of a character device option is: 3246 3247``-chardev backend,id=id[,mux=on|off][,options]`` 3248 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3249 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3250 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3251 ``spicevmc``, ``spiceport``. The specific backend will determine the 3252 applicable options. 3253 3254 Use ``-chardev help`` to print all available chardev backend types. 3255 3256 All devices must have an id, which can be any string up to 127 3257 characters long. It is used to uniquely identify this device in 3258 other command line directives. 3259 3260 A character device may be used in multiplexing mode by multiple 3261 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3262 a "1:N" device, and here the "1" end is your specified chardev 3263 backend, and the "N" end is the various parts of QEMU that can talk 3264 to a chardev. If you create a chardev with ``id=myid`` and 3265 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3266 and you can then configure multiple front ends to use that chardev 3267 ID for their input/output. Up to four different front ends can be 3268 connected to a single multiplexed chardev. (Without multiplexing 3269 enabled, a chardev can only be used by a single front end.) For 3270 instance you could use this to allow a single stdio chardev to be 3271 used by two serial ports and the QEMU monitor: 3272 3273 :: 3274 3275 -chardev stdio,mux=on,id=char0 \ 3276 -mon chardev=char0,mode=readline \ 3277 -serial chardev:char0 \ 3278 -serial chardev:char0 3279 3280 You can have more than one multiplexer in a system configuration; 3281 for instance you could have a TCP port multiplexed between UART 0 3282 and UART 1, and stdio multiplexed between the QEMU monitor and a 3283 parallel port: 3284 3285 :: 3286 3287 -chardev stdio,mux=on,id=char0 \ 3288 -mon chardev=char0,mode=readline \ 3289 -parallel chardev:char0 \ 3290 -chardev tcp,...,mux=on,id=char1 \ 3291 -serial chardev:char1 \ 3292 -serial chardev:char1 3293 3294 When you're using a multiplexed character device, some escape 3295 sequences are interpreted in the input. See the chapter about 3296 :ref:`keys in the character backend multiplexer` in the 3297 System Emulation Users Guide for more details. 3298 3299 Note that some other command line options may implicitly create 3300 multiplexed character backends; for instance ``-serial mon:stdio`` 3301 creates a multiplexed stdio backend connected to the serial port and 3302 the QEMU monitor, and ``-nographic`` also multiplexes the console 3303 and the monitor to stdio. 3304 3305 There is currently no support for multiplexing in the other 3306 direction (where a single QEMU front end takes input and output from 3307 multiple chardevs). 3308 3309 Every backend supports the ``logfile`` option, which supplies the 3310 path to a file to record all data transmitted via the backend. The 3311 ``logappend`` option controls whether the log file will be truncated 3312 or appended to when opened. 3313 3314The available backends are: 3315 3316``-chardev null,id=id`` 3317 A void device. This device will not emit any data, and will drop any 3318 data it receives. The null backend does not take any options. 3319 3320``-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]`` 3321 Create a two-way stream socket, which can be either a TCP or a unix 3322 socket. A unix socket will be created if ``path`` is specified. 3323 Behaviour is undefined if TCP options are specified for a unix 3324 socket. 3325 3326 ``server=on|off`` specifies that the socket shall be a listening socket. 3327 3328 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3329 to connect to a listening socket. 3330 3331 ``telnet=on|off`` specifies that traffic on the socket should interpret 3332 telnet escape sequences. 3333 3334 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3335 communication. 3336 3337 ``reconnect`` sets the timeout for reconnecting on non-server 3338 sockets when the remote end goes away. qemu will delay this many 3339 seconds and then attempt to reconnect. Zero disables reconnecting, 3340 and is the default. 3341 3342 ``tls-creds`` requests enablement of the TLS protocol for 3343 encryption, and specifies the id of the TLS credentials to use for 3344 the handshake. The credentials must be previously created with the 3345 ``-object tls-creds`` argument. 3346 3347 ``tls-auth`` provides the ID of the QAuthZ authorization object 3348 against which the client's x509 distinguished name will be 3349 validated. This object is only resolved at time of use, so can be 3350 deleted and recreated on the fly while the chardev server is active. 3351 If missing, it will default to denying access. 3352 3353 TCP and unix socket options are given below: 3354 3355 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3356 ``host`` for a listening socket specifies the local address to 3357 be bound. For a connecting socket species the remote host to 3358 connect to. ``host`` is optional for listening sockets. If not 3359 specified it defaults to ``0.0.0.0``. 3360 3361 ``port`` for a listening socket specifies the local port to be 3362 bound. For a connecting socket specifies the port on the remote 3363 host to connect to. ``port`` can be given as either a port 3364 number or a service name. ``port`` is required. 3365 3366 ``to`` is only relevant to listening sockets. If it is 3367 specified, and ``port`` cannot be bound, QEMU will attempt to 3368 bind to subsequent ports up to and including ``to`` until it 3369 succeeds. ``to`` must be specified as a port number. 3370 3371 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3372 or IPv6 must be used. If neither is specified the socket may 3373 use either protocol. 3374 3375 ``nodelay=on|off`` disables the Nagle algorithm. 3376 3377 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3378 ``path`` specifies the local path of the unix socket. ``path`` 3379 is required. 3380 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3381 rather than the filesystem. Optional, defaults to false. 3382 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3383 rather than the full sun_path length. Optional, defaults to true. 3384 3385``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3386 Sends all traffic from the guest to a remote host over UDP. 3387 3388 ``host`` specifies the remote host to connect to. If not specified 3389 it defaults to ``localhost``. 3390 3391 ``port`` specifies the port on the remote host to connect to. 3392 ``port`` is required. 3393 3394 ``localaddr`` specifies the local address to bind to. If not 3395 specified it defaults to ``0.0.0.0``. 3396 3397 ``localport`` specifies the local port to bind to. If not specified 3398 any available local port will be used. 3399 3400 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3401 If neither is specified the device may use either protocol. 3402 3403``-chardev msmouse,id=id`` 3404 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3405 does not take any options. 3406 3407``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3408 Connect to a QEMU text console. ``vc`` may optionally be given a 3409 specific size. 3410 3411 ``width`` and ``height`` specify the width and height respectively 3412 of the console, in pixels. 3413 3414 ``cols`` and ``rows`` specify that the console be sized to fit a 3415 text console with the given dimensions. 3416 3417``-chardev ringbuf,id=id[,size=size]`` 3418 Create a ring buffer with fixed size ``size``. size must be a power 3419 of two and defaults to ``64K``. 3420 3421``-chardev file,id=id,path=path`` 3422 Log all traffic received from the guest to a file. 3423 3424 ``path`` specifies the path of the file to be opened. This file will 3425 be created if it does not already exist, and overwritten if it does. 3426 ``path`` is required. 3427 3428``-chardev pipe,id=id,path=path`` 3429 Create a two-way connection to the guest. The behaviour differs 3430 slightly between Windows hosts and other hosts: 3431 3432 On Windows, a single duplex pipe will be created at 3433 ``\\.pipe\path``. 3434 3435 On other hosts, 2 pipes will be created called ``path.in`` and 3436 ``path.out``. Data written to ``path.in`` will be received by the 3437 guest. Data written by the guest can be read from ``path.out``. QEMU 3438 will not create these fifos, and requires them to be present. 3439 3440 ``path`` forms part of the pipe path as described above. ``path`` is 3441 required. 3442 3443``-chardev console,id=id`` 3444 Send traffic from the guest to QEMU's standard output. ``console`` 3445 does not take any options. 3446 3447 ``console`` is only available on Windows hosts. 3448 3449``-chardev serial,id=id,path=path`` 3450 Send traffic from the guest to a serial device on the host. 3451 3452 On Unix hosts serial will actually accept any tty device, not only 3453 serial lines. 3454 3455 ``path`` specifies the name of the serial device to open. 3456 3457``-chardev pty,id=id`` 3458 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3459 does not take any options. 3460 3461 ``pty`` is not available on Windows hosts. 3462 3463``-chardev stdio,id=id[,signal=on|off]`` 3464 Connect to standard input and standard output of the QEMU process. 3465 3466 ``signal`` controls if signals are enabled on the terminal, that 3467 includes exiting QEMU with the key sequence Control-c. This option 3468 is enabled by default, use ``signal=off`` to disable it. 3469 3470``-chardev braille,id=id`` 3471 Connect to a local BrlAPI server. ``braille`` does not take any 3472 options. 3473 3474``-chardev tty,id=id,path=path`` 3475 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3476 and DragonFlyBSD hosts. It is an alias for ``serial``. 3477 3478 ``path`` specifies the path to the tty. ``path`` is required. 3479 3480``-chardev parallel,id=id,path=path`` 3481 \ 3482``-chardev parport,id=id,path=path`` 3483 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3484 hosts. 3485 3486 Connect to a local parallel port. 3487 3488 ``path`` specifies the path to the parallel port device. ``path`` is 3489 required. 3490 3491``-chardev spicevmc,id=id,debug=debug,name=name`` 3492 ``spicevmc`` is only available when spice support is built in. 3493 3494 ``debug`` debug level for spicevmc 3495 3496 ``name`` name of spice channel to connect to 3497 3498 Connect to a spice virtual machine channel, such as vdiport. 3499 3500``-chardev spiceport,id=id,debug=debug,name=name`` 3501 ``spiceport`` is only available when spice support is built in. 3502 3503 ``debug`` debug level for spicevmc 3504 3505 ``name`` name of spice port to connect to 3506 3507 Connect to a spice port, allowing a Spice client to handle the 3508 traffic identified by a name (preferably a fqdn). 3509ERST 3510 3511DEFHEADING() 3512 3513#ifdef CONFIG_TPM 3514DEFHEADING(TPM device options:) 3515 3516DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3517 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3518 " use path to provide path to a character device; default is /dev/tpm0\n" 3519 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3520 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3521 "-tpmdev emulator,id=id,chardev=dev\n" 3522 " configure the TPM device using chardev backend\n", 3523 QEMU_ARCH_ALL) 3524SRST 3525The general form of a TPM device option is: 3526 3527``-tpmdev backend,id=id[,options]`` 3528 The specific backend type will determine the applicable options. The 3529 ``-tpmdev`` option creates the TPM backend and requires a 3530 ``-device`` option that specifies the TPM frontend interface model. 3531 3532 Use ``-tpmdev help`` to print all available TPM backend types. 3533 3534The available backends are: 3535 3536``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3537 (Linux-host only) Enable access to the host's TPM using the 3538 passthrough driver. 3539 3540 ``path`` specifies the path to the host's TPM device, i.e., on a 3541 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3542 default ``/dev/tpm0`` is used. 3543 3544 ``cancel-path`` specifies the path to the host TPM device's sysfs 3545 entry allowing for cancellation of an ongoing TPM command. 3546 ``cancel-path`` is optional and by default QEMU will search for the 3547 sysfs entry to use. 3548 3549 Some notes about using the host's TPM with the passthrough driver: 3550 3551 The TPM device accessed by the passthrough driver must not be used 3552 by any other application on the host. 3553 3554 Since the host's firmware (BIOS/UEFI) has already initialized the 3555 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3556 the TPM again and may therefore not show a TPM-specific menu that 3557 would otherwise allow the user to configure the TPM, e.g., allow the 3558 user to enable/disable or activate/deactivate the TPM. Further, if 3559 TPM ownership is released from within a VM then the host's TPM will 3560 get disabled and deactivated. To enable and activate the TPM again 3561 afterwards, the host has to be rebooted and the user is required to 3562 enter the firmware's menu to enable and activate the TPM. If the TPM 3563 is left disabled and/or deactivated most TPM commands will fail. 3564 3565 To create a passthrough TPM use the following two options: 3566 3567 :: 3568 3569 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3570 3571 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3572 ``tpmdev=tpm0`` in the device option. 3573 3574``-tpmdev emulator,id=id,chardev=dev`` 3575 (Linux-host only) Enable access to a TPM emulator using Unix domain 3576 socket based chardev backend. 3577 3578 ``chardev`` specifies the unique ID of a character device backend 3579 that provides connection to the software TPM server. 3580 3581 To create a TPM emulator backend device with chardev socket backend: 3582 3583 :: 3584 3585 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3586ERST 3587 3588DEFHEADING() 3589 3590#endif 3591 3592DEFHEADING(Linux/Multiboot boot specific:) 3593SRST 3594When using these options, you can use a given Linux or Multiboot kernel 3595without installing it in the disk image. It can be useful for easier 3596testing of various kernels. 3597 3598 3599ERST 3600 3601DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3602 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3603SRST 3604``-kernel bzImage`` 3605 Use bzImage as kernel image. The kernel can be either a Linux kernel 3606 or in multiboot format. 3607ERST 3608 3609DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3610 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3611SRST 3612``-append cmdline`` 3613 Use cmdline as kernel command line 3614ERST 3615 3616DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3617 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3618SRST 3619``-initrd file`` 3620 Use file as initial ram disk. 3621 3622``-initrd "file1 arg=foo,file2"`` 3623 This syntax is only available with multiboot. 3624 3625 Use file1 and file2 as modules and pass arg=foo as parameter to the 3626 first module. 3627ERST 3628 3629DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3630 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3631SRST 3632``-dtb file`` 3633 Use file as a device tree binary (dtb) image and pass it to the 3634 kernel on boot. 3635ERST 3636 3637DEFHEADING() 3638 3639DEFHEADING(Debug/Expert options:) 3640 3641DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3642 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3643 " Policy for handling deprecated management interfaces\n", 3644 QEMU_ARCH_ALL) 3645SRST 3646``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3647 Set policy for handling deprecated management interfaces (experimental): 3648 3649 ``deprecated-input=accept`` (default) 3650 Accept deprecated commands and arguments 3651 ``deprecated-input=reject`` 3652 Reject deprecated commands and arguments 3653 ``deprecated-input=crash`` 3654 Crash on deprecated commands and arguments 3655 ``deprecated-output=accept`` (default) 3656 Emit deprecated command results and events 3657 ``deprecated-output=hide`` 3658 Suppress deprecated command results and events 3659 3660 Limitation: covers only syntactic aspects of QMP. 3661ERST 3662 3663DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3664 "-fw_cfg [name=]<name>,file=<file>\n" 3665 " add named fw_cfg entry with contents from file\n" 3666 "-fw_cfg [name=]<name>,string=<str>\n" 3667 " add named fw_cfg entry with contents from string\n", 3668 QEMU_ARCH_ALL) 3669SRST 3670``-fw_cfg [name=]name,file=file`` 3671 Add named fw\_cfg entry with contents from file file. 3672 3673``-fw_cfg [name=]name,string=str`` 3674 Add named fw\_cfg entry with contents from string str. 3675 3676 The terminating NUL character of the contents of str will not be 3677 included as part of the fw\_cfg item data. To insert contents with 3678 embedded NUL characters, you have to use the file parameter. 3679 3680 The fw\_cfg entries are passed by QEMU through to the guest. 3681 3682 Example: 3683 3684 :: 3685 3686 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3687 3688 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3689 from ./my\_blob.bin. 3690ERST 3691 3692DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3693 "-serial dev redirect the serial port to char device 'dev'\n", 3694 QEMU_ARCH_ALL) 3695SRST 3696``-serial dev`` 3697 Redirect the virtual serial port to host character device dev. The 3698 default device is ``vc`` in graphical mode and ``stdio`` in non 3699 graphical mode. 3700 3701 This option can be used several times to simulate up to 4 serial 3702 ports. 3703 3704 Use ``-serial none`` to disable all serial ports. 3705 3706 Available character devices are: 3707 3708 ``vc[:WxH]`` 3709 Virtual console. Optionally, a width and height can be given in 3710 pixel with 3711 3712 :: 3713 3714 vc:800x600 3715 3716 It is also possible to specify width or height in characters: 3717 3718 :: 3719 3720 vc:80Cx24C 3721 3722 ``pty`` 3723 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3724 3725 ``none`` 3726 No device is allocated. 3727 3728 ``null`` 3729 void device 3730 3731 ``chardev:id`` 3732 Use a named character device defined with the ``-chardev`` 3733 option. 3734 3735 ``/dev/XXX`` 3736 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3737 port parameters are set according to the emulated ones. 3738 3739 ``/dev/parportN`` 3740 [Linux only, parallel port only] Use host parallel port N. 3741 Currently SPP and EPP parallel port features can be used. 3742 3743 ``file:filename`` 3744 Write output to filename. No character can be read. 3745 3746 ``stdio`` 3747 [Unix only] standard input/output 3748 3749 ``pipe:filename`` 3750 name pipe filename 3751 3752 ``COMn`` 3753 [Windows only] Use host serial port n 3754 3755 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3756 This implements UDP Net Console. When remote\_host or src\_ip 3757 are not specified they default to ``0.0.0.0``. When not using a 3758 specified src\_port a random port is automatically chosen. 3759 3760 If you just want a simple readonly console you can use 3761 ``netcat`` or ``nc``, by starting QEMU with: 3762 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3763 QEMU writes something to that port it will appear in the 3764 netconsole session. 3765 3766 If you plan to send characters back via netconsole or you want 3767 to stop and start QEMU a lot of times, you should have QEMU use 3768 the same source port each time by using something like ``-serial 3769 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3770 version of netcat which can listen to a TCP port and send and 3771 receive characters via udp. If you have a patched version of 3772 netcat which activates telnet remote echo and single char 3773 transfer, then you can use the following options to set up a 3774 netcat redirector to allow telnet on port 5555 to access the 3775 QEMU port. 3776 3777 ``QEMU Options:`` 3778 -serial udp::4555@:4556 3779 3780 ``netcat options:`` 3781 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3782 3783 ``telnet options:`` 3784 localhost 5555 3785 3786 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3787 The TCP Net Console has two modes of operation. It can send the 3788 serial I/O to a location or wait for a connection from a 3789 location. By default the TCP Net Console is sent to host at the 3790 port. If you use the ``server=on`` option QEMU will wait for a client 3791 socket application to connect to the port before continuing, 3792 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3793 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3794 option only applies if ``server=no`` is set, if the connection goes 3795 down it will attempt to reconnect at the given interval. If host 3796 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3797 time is accepted. You can use ``telnet=on`` to connect to the 3798 corresponding character device. 3799 3800 ``Example to send tcp console to 192.168.0.2 port 4444`` 3801 -serial tcp:192.168.0.2:4444 3802 3803 ``Example to listen and wait on port 4444 for connection`` 3804 -serial tcp::4444,server=on 3805 3806 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3807 -serial tcp:192.168.0.100:4444,server=on,wait=off 3808 3809 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3810 The telnet protocol is used instead of raw tcp sockets. The 3811 options work the same as if you had specified ``-serial tcp``. 3812 The difference is that the port acts like a telnet server or 3813 client using telnet option negotiation. This will also allow you 3814 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3815 supports sending the break sequence. Typically in unix telnet 3816 you do it with Control-] and then type "send break" followed by 3817 pressing the enter key. 3818 3819 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3820 The WebSocket protocol is used instead of raw tcp socket. The 3821 port acts as a WebSocket server. Client mode is not supported. 3822 3823 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3824 A unix domain socket is used instead of a tcp socket. The option 3825 works the same as if you had specified ``-serial tcp`` except 3826 the unix domain socket path is used for connections. 3827 3828 ``mon:dev_string`` 3829 This is a special option to allow the monitor to be multiplexed 3830 onto another serial port. The monitor is accessed with key 3831 sequence of Control-a and then pressing c. dev\_string should be 3832 any one of the serial devices specified above. An example to 3833 multiplex the monitor onto a telnet server listening on port 3834 4444 would be: 3835 3836 ``-serial mon:telnet::4444,server=on,wait=off`` 3837 3838 When the monitor is multiplexed to stdio in this way, Ctrl+C 3839 will not terminate QEMU any more but will be passed to the guest 3840 instead. 3841 3842 ``braille`` 3843 Braille device. This will use BrlAPI to display the braille 3844 output on a real or fake device. 3845 3846 ``msmouse`` 3847 Three button serial mouse. Configure the guest to use Microsoft 3848 protocol. 3849ERST 3850 3851DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3852 "-parallel dev redirect the parallel port to char device 'dev'\n", 3853 QEMU_ARCH_ALL) 3854SRST 3855``-parallel dev`` 3856 Redirect the virtual parallel port to host device dev (same devices 3857 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3858 to use hardware devices connected on the corresponding host parallel 3859 port. 3860 3861 This option can be used several times to simulate up to 3 parallel 3862 ports. 3863 3864 Use ``-parallel none`` to disable all parallel ports. 3865ERST 3866 3867DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3868 "-monitor dev redirect the monitor to char device 'dev'\n", 3869 QEMU_ARCH_ALL) 3870SRST 3871``-monitor dev`` 3872 Redirect the monitor to host device dev (same devices as the serial 3873 port). The default device is ``vc`` in graphical mode and ``stdio`` 3874 in non graphical mode. Use ``-monitor none`` to disable the default 3875 monitor. 3876ERST 3877DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3878 "-qmp dev like -monitor but opens in 'control' mode\n", 3879 QEMU_ARCH_ALL) 3880SRST 3881``-qmp dev`` 3882 Like -monitor but opens in 'control' mode. 3883ERST 3884DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3885 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3886 QEMU_ARCH_ALL) 3887SRST 3888``-qmp-pretty dev`` 3889 Like -qmp but uses pretty JSON formatting. 3890ERST 3891 3892DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3893 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3894SRST 3895``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3896 Setup monitor on chardev name. ``mode=control`` configures 3897 a QMP monitor (a JSON RPC-style protocol) and it is not the 3898 same as HMP, the human monitor that has a "(qemu)" prompt. 3899 ``pretty`` is only valid when ``mode=control``, 3900 turning on JSON pretty printing to ease 3901 human reading and debugging. 3902ERST 3903 3904DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3905 "-debugcon dev redirect the debug console to char device 'dev'\n", 3906 QEMU_ARCH_ALL) 3907SRST 3908``-debugcon dev`` 3909 Redirect the debug console to host device dev (same devices as the 3910 serial port). The debug console is an I/O port which is typically 3911 port 0xe9; writing to that I/O port sends output to this device. The 3912 default device is ``vc`` in graphical mode and ``stdio`` in non 3913 graphical mode. 3914ERST 3915 3916DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3917 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3918SRST 3919``-pidfile file`` 3920 Store the QEMU process PID in file. It is useful if you launch QEMU 3921 from a script. 3922ERST 3923 3924DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3925 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3926SRST 3927``-singlestep`` 3928 Run the emulation in single step mode. 3929ERST 3930 3931DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3932 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3933 QEMU_ARCH_ALL) 3934SRST 3935``--preconfig`` 3936 Pause QEMU for interactive configuration before the machine is 3937 created, which allows querying and configuring properties that will 3938 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3939 exit the preconfig state and move to the next state (i.e. run guest 3940 if -S isn't used or pause the second time if -S is used). This 3941 option is experimental. 3942ERST 3943 3944DEF("S", 0, QEMU_OPTION_S, \ 3945 "-S freeze CPU at startup (use 'c' to start execution)\n", 3946 QEMU_ARCH_ALL) 3947SRST 3948``-S`` 3949 Do not start CPU at startup (you must type 'c' in the monitor). 3950ERST 3951 3952DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3953 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3954 " run qemu with overcommit hints\n" 3955 " mem-lock=on|off controls memory lock support (default: off)\n" 3956 " cpu-pm=on|off controls cpu power management (default: off)\n", 3957 QEMU_ARCH_ALL) 3958SRST 3959``-overcommit mem-lock=on|off`` 3960 \ 3961``-overcommit cpu-pm=on|off`` 3962 Run qemu with hints about host resource overcommit. The default is 3963 to assume that host overcommits all resources. 3964 3965 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3966 (disabled by default). This works when host memory is not 3967 overcommitted and reduces the worst-case latency for guest. 3968 3969 Guest ability to manage power state of host cpus (increasing latency 3970 for other processes on the same host cpu, but decreasing latency for 3971 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3972 works best when host CPU is not overcommitted. When used, host 3973 estimates of CPU cycle and power utilization will be incorrect, not 3974 taking into account guest idle time. 3975ERST 3976 3977DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3978 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3979 " the guest without waiting for gdb to connect; use -S too\n" 3980 " if you want it to not start execution.)\n", 3981 QEMU_ARCH_ALL) 3982SRST 3983``-gdb dev`` 3984 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3985 in the System Emulation Users Guide). Note that this option does not pause QEMU 3986 execution -- if you want QEMU to not start the guest until you 3987 connect with gdb and issue a ``continue`` command, you will need to 3988 also pass the ``-S`` option to QEMU. 3989 3990 The most usual configuration is to listen on a local TCP socket:: 3991 3992 -gdb tcp::3117 3993 3994 but you can specify other backends; UDP, pseudo TTY, or even stdio 3995 are all reasonable use cases. For example, a stdio connection 3996 allows you to start QEMU from within gdb and establish the 3997 connection via a pipe: 3998 3999 .. parsed-literal:: 4000 4001 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4002ERST 4003 4004DEF("s", 0, QEMU_OPTION_s, \ 4005 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4006 QEMU_ARCH_ALL) 4007SRST 4008``-s`` 4009 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4010 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4011ERST 4012 4013DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4014 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4015 QEMU_ARCH_ALL) 4016SRST 4017``-d item1[,...]`` 4018 Enable logging of specified items. Use '-d help' for a list of log 4019 items. 4020ERST 4021 4022DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4023 "-D logfile output log to logfile (default stderr)\n", 4024 QEMU_ARCH_ALL) 4025SRST 4026``-D logfile`` 4027 Output log in logfile instead of to stderr 4028ERST 4029 4030DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4031 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4032 QEMU_ARCH_ALL) 4033SRST 4034``-dfilter range1[,...]`` 4035 Filter debug output to that relevant to a range of target addresses. 4036 The filter spec can be either start+size, start-size or start..end 4037 where start end and size are the addresses and sizes required. For 4038 example: 4039 4040 :: 4041 4042 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4043 4044 Will dump output for any code in the 0x1000 sized block starting at 4045 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4046 another 0x1000 sized block starting at 0xffffffc00005f000. 4047ERST 4048 4049DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4050 "-seed number seed the pseudo-random number generator\n", 4051 QEMU_ARCH_ALL) 4052SRST 4053``-seed number`` 4054 Force the guest to use a deterministic pseudo-random number 4055 generator, seeded with number. This does not affect crypto routines 4056 within the host. 4057ERST 4058 4059DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4060 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4061 QEMU_ARCH_ALL) 4062SRST 4063``-L path`` 4064 Set the directory for the BIOS, VGA BIOS and keymaps. 4065 4066 To list all the data directories, use ``-L help``. 4067ERST 4068 4069DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4070 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4071SRST 4072``-bios file`` 4073 Set the filename for the BIOS. 4074ERST 4075 4076DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4077 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 4078SRST 4079``-enable-kvm`` 4080 Enable KVM full virtualization support. This option is only 4081 available if KVM support is enabled when compiling. 4082ERST 4083 4084DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4085 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 4086DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4087 "-xen-attach attach to existing xen domain\n" 4088 " libxl will use this when starting QEMU\n", 4089 QEMU_ARCH_ALL) 4090DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4091 "-xen-domid-restrict restrict set of available xen operations\n" 4092 " to specified domain id. (Does not affect\n" 4093 " xenpv machine type).\n", 4094 QEMU_ARCH_ALL) 4095SRST 4096``-xen-domid id`` 4097 Specify xen guest domain id (XEN only). 4098 4099``-xen-attach`` 4100 Attach to existing xen domain. libxl will use this when starting 4101 QEMU (XEN only). Restrict set of available xen operations to 4102 specified domain id (XEN only). 4103ERST 4104 4105DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4106 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4107SRST 4108``-no-reboot`` 4109 Exit instead of rebooting. 4110ERST 4111 4112DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4113 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4114SRST 4115``-no-shutdown`` 4116 Don't exit QEMU on guest shutdown, but instead only stop the 4117 emulation. This allows for instance switching to monitor to commit 4118 changes to the disk image. 4119ERST 4120 4121DEF("action", HAS_ARG, QEMU_OPTION_action, 4122 "-action reboot=reset|shutdown\n" 4123 " action when guest reboots [default=reset]\n" 4124 "-action shutdown=poweroff|pause\n" 4125 " action when guest shuts down [default=poweroff]\n" 4126 "-action panic=pause|shutdown|none\n" 4127 " action when guest panics [default=shutdown]\n" 4128 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4129 " action when watchdog fires [default=reset]\n", 4130 QEMU_ARCH_ALL) 4131SRST 4132``-action event=action`` 4133 The action parameter serves to modify QEMU's default behavior when 4134 certain guest events occur. It provides a generic method for specifying the 4135 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4136 parameters. 4137 4138 Examples: 4139 4140 ``-action panic=none`` 4141 ``-action reboot=shutdown,shutdown=pause`` 4142 ``-watchdog i6300esb -action watchdog=pause`` 4143 4144ERST 4145 4146DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4147 "-loadvm [tag|id]\n" \ 4148 " start right away with a saved state (loadvm in monitor)\n", 4149 QEMU_ARCH_ALL) 4150SRST 4151``-loadvm file`` 4152 Start right away with a saved state (``loadvm`` in monitor) 4153ERST 4154 4155#ifndef _WIN32 4156DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4157 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4158#endif 4159SRST 4160``-daemonize`` 4161 Daemonize the QEMU process after initialization. QEMU will not 4162 detach from standard IO until it is ready to receive connections on 4163 any of its devices. This option is a useful way for external 4164 programs to launch QEMU without having to cope with initialization 4165 race conditions. 4166ERST 4167 4168DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4169 "-option-rom rom load a file, rom, into the option ROM space\n", 4170 QEMU_ARCH_ALL) 4171SRST 4172``-option-rom file`` 4173 Load the contents of file as an option ROM. This option is useful to 4174 load things like EtherBoot. 4175ERST 4176 4177DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4178 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4179 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4180 QEMU_ARCH_ALL) 4181 4182SRST 4183``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4184 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4185 the current UTC or local time, respectively. ``localtime`` is 4186 required for correct date in MS-DOS or Windows. To start at a 4187 specific point in time, provide datetime in the format 4188 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4189 4190 By default the RTC is driven by the host system time. This allows 4191 using of the RTC as accurate reference clock inside the guest, 4192 specifically if the host time is smoothly following an accurate 4193 external reference clock, e.g. via NTP. If you want to isolate the 4194 guest time from the host, you can set ``clock`` to ``rt`` instead, 4195 which provides a host monotonic clock if host support it. To even 4196 prevent the RTC from progressing during suspension, you can set 4197 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4198 recommended especially in icount mode in order to preserve 4199 determinism; however, note that in icount mode the speed of the 4200 virtual clock is variable and can in general differ from the host 4201 clock. 4202 4203 Enable ``driftfix`` (i386 targets only) if you experience time drift 4204 problems, specifically with Windows' ACPI HAL. This option will try 4205 to figure out how many timer interrupts were not processed by the 4206 Windows guest and will re-inject them. 4207ERST 4208 4209DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4210 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4211 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4212 " instruction, enable aligning the host and virtual clocks\n" \ 4213 " or disable real time cpu sleeping, and optionally enable\n" \ 4214 " record-and-replay mode\n", QEMU_ARCH_ALL) 4215SRST 4216``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4217 Enable virtual instruction counter. The virtual cpu will execute one 4218 instruction every 2^N ns of virtual time. If ``auto`` is specified 4219 then the virtual cpu speed will be automatically adjusted to keep 4220 virtual time within a few seconds of real time. 4221 4222 Note that while this option can give deterministic behavior, it does 4223 not provide cycle accurate emulation. Modern CPUs contain 4224 superscalar out of order cores with complex cache hierarchies. The 4225 number of instructions executed often has little or no correlation 4226 with actual performance. 4227 4228 When the virtual cpu is sleeping, the virtual time will advance at 4229 default speed unless ``sleep=on`` is specified. With 4230 ``sleep=on``, the virtual time will jump to the next timer 4231 deadline instantly whenever the virtual cpu goes to sleep mode and 4232 will not advance if no timer is enabled. This behavior gives 4233 deterministic execution times from the guest point of view. 4234 The default if icount is enabled is ``sleep=off``. 4235 ``sleep=on`` cannot be used together with either ``shift=auto`` 4236 or ``align=on``. 4237 4238 ``align=on`` will activate the delay algorithm which will try to 4239 synchronise the host clock and the virtual clock. The goal is to 4240 have a guest running at the real frequency imposed by the shift 4241 option. Whenever the guest clock is behind the host clock and if 4242 ``align=on`` is specified then we print a message to the user to 4243 inform about the delay. Currently this option does not work when 4244 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4245 shift values for which the guest clock runs ahead of the host clock. 4246 Typically this happens when the shift value is high (how high 4247 depends on the host machine). The default if icount is enabled 4248 is ``align=off``. 4249 4250 When the ``rr`` option is specified deterministic record/replay is 4251 enabled. The ``rrfile=`` option must also be provided to 4252 specify the path to the replay log. In record mode data is written 4253 to this file, and in replay mode it is read back. 4254 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4255 name. In record mode, a new VM snapshot with the given name is created 4256 at the start of execution recording. In replay mode this option 4257 specifies the snapshot name used to load the initial VM state. 4258ERST 4259 4260DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4261 "-watchdog model\n" \ 4262 " enable virtual hardware watchdog [default=none]\n", 4263 QEMU_ARCH_ALL) 4264SRST 4265``-watchdog model`` 4266 Create a virtual hardware watchdog device. Once enabled (by a guest 4267 action), the watchdog must be periodically polled by an agent inside 4268 the guest or else the guest will be restarted. Choose a model for 4269 which your guest has drivers. 4270 4271 The model is the model of hardware watchdog to emulate. Use 4272 ``-watchdog help`` to list available hardware models. Only one 4273 watchdog can be enabled for a guest. 4274 4275 The following models may be available: 4276 4277 ``ib700`` 4278 iBASE 700 is a very simple ISA watchdog with a single timer. 4279 4280 ``i6300esb`` 4281 Intel 6300ESB I/O controller hub is a much more featureful 4282 PCI-based dual-timer watchdog. 4283 4284 ``diag288`` 4285 A virtual watchdog for s390x backed by the diagnose 288 4286 hypercall (currently KVM only). 4287ERST 4288 4289DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4290 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4291 " action when watchdog fires [default=reset]\n", 4292 QEMU_ARCH_ALL) 4293SRST 4294``-watchdog-action action`` 4295 The action controls what QEMU will do when the watchdog timer 4296 expires. The default is ``reset`` (forcefully reset the guest). 4297 Other possible actions are: ``shutdown`` (attempt to gracefully 4298 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4299 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4300 guest), ``debug`` (print a debug message and continue), or ``none`` 4301 (do nothing). 4302 4303 Note that the ``shutdown`` action requires that the guest responds 4304 to ACPI signals, which it may not be able to do in the sort of 4305 situations where the watchdog would have expired, and thus 4306 ``-watchdog-action shutdown`` is not recommended for production use. 4307 4308 Examples: 4309 4310 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4311 4312ERST 4313 4314DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4315 "-echr chr set terminal escape character instead of ctrl-a\n", 4316 QEMU_ARCH_ALL) 4317SRST 4318``-echr numeric_ascii_value`` 4319 Change the escape character used for switching to the monitor when 4320 using monitor and serial sharing. The default is ``0x01`` when using 4321 the ``-nographic`` option. ``0x01`` is equal to pressing 4322 ``Control-a``. You can select a different character from the ascii 4323 control keys where 1 through 26 map to Control-a through Control-z. 4324 For instance you could use the either of the following to change the 4325 escape character to Control-t. 4326 4327 ``-echr 0x14``; \ ``-echr 20`` 4328 4329ERST 4330 4331DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4332 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4333 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4334 "-incoming unix:socketpath\n" \ 4335 " prepare for incoming migration, listen on\n" \ 4336 " specified protocol and socket address\n" \ 4337 "-incoming fd:fd\n" \ 4338 "-incoming exec:cmdline\n" \ 4339 " accept incoming migration on given file descriptor\n" \ 4340 " or from given external command\n" \ 4341 "-incoming defer\n" \ 4342 " wait for the URI to be specified via migrate_incoming\n", 4343 QEMU_ARCH_ALL) 4344SRST 4345``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4346 \ 4347``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4348 Prepare for incoming migration, listen on a given tcp port. 4349 4350``-incoming unix:socketpath`` 4351 Prepare for incoming migration, listen on a given unix socket. 4352 4353``-incoming fd:fd`` 4354 Accept incoming migration from a given filedescriptor. 4355 4356``-incoming exec:cmdline`` 4357 Accept incoming migration as an output from specified external 4358 command. 4359 4360``-incoming defer`` 4361 Wait for the URI to be specified via migrate\_incoming. The monitor 4362 can be used to change settings (such as migration parameters) prior 4363 to issuing the migrate\_incoming to allow the migration to begin. 4364ERST 4365 4366DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4367 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4368SRST 4369``-only-migratable`` 4370 Only allow migratable devices. Devices will not be allowed to enter 4371 an unmigratable state. 4372ERST 4373 4374DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4375 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4376SRST 4377``-nodefaults`` 4378 Don't create default devices. Normally, QEMU sets the default 4379 devices like serial port, parallel port, virtual console, monitor 4380 device, VGA adapter, floppy and CD-ROM drive and others. The 4381 ``-nodefaults`` option will disable all those default devices. 4382ERST 4383 4384#ifndef _WIN32 4385DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4386 "-chroot dir chroot to dir just before starting the VM\n", 4387 QEMU_ARCH_ALL) 4388#endif 4389SRST 4390``-chroot dir`` 4391 Immediately before starting guest execution, chroot to the specified 4392 directory. Especially useful in combination with -runas. 4393ERST 4394 4395#ifndef _WIN32 4396DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4397 "-runas user change to user id user just before starting the VM\n" \ 4398 " user can be numeric uid:gid instead\n", 4399 QEMU_ARCH_ALL) 4400#endif 4401SRST 4402``-runas user`` 4403 Immediately before starting guest execution, drop root privileges, 4404 switching to the specified user. 4405ERST 4406 4407DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4408 "-prom-env variable=value\n" 4409 " set OpenBIOS nvram variables\n", 4410 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4411SRST 4412``-prom-env variable=value`` 4413 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4414 4415 :: 4416 4417 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4418 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4419 4420 :: 4421 4422 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4423 -prom-env 'boot-device=hd:2,\yaboot' \ 4424 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4425ERST 4426DEF("semihosting", 0, QEMU_OPTION_semihosting, 4427 "-semihosting semihosting mode\n", 4428 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4429 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4430SRST 4431``-semihosting`` 4432 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4433 4434 Note that this allows guest direct access to the host filesystem, so 4435 should only be used with a trusted guest OS. 4436 4437 See the -semihosting-config option documentation for further 4438 information about the facilities this enables. 4439ERST 4440DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4441 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4442 " semihosting configuration\n", 4443QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4444QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4445SRST 4446``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4447 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4448 only). 4449 4450 Note that this allows guest direct access to the host filesystem, so 4451 should only be used with a trusted guest OS. 4452 4453 On Arm this implements the standard semihosting API, version 2.0. 4454 4455 On M68K this implements the "ColdFire GDB" interface used by 4456 libgloss. 4457 4458 Xtensa semihosting provides basic file IO calls, such as 4459 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4460 linux platform "sim" use this interface. 4461 4462 On RISC-V this implements the standard semihosting API, version 0.2. 4463 4464 ``target=native|gdb|auto`` 4465 Defines where the semihosting calls will be addressed, to QEMU 4466 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4467 means ``gdb`` during debug sessions and ``native`` otherwise. 4468 4469 ``chardev=str1`` 4470 Send the output to a chardev backend output for native or auto 4471 output when not in gdb 4472 4473 ``arg=str1,arg=str2,...`` 4474 Allows the user to pass input arguments, and can be used 4475 multiple times to build up a list. The old-style 4476 ``-kernel``/``-append`` method of passing a command line is 4477 still supported for backward compatibility. If both the 4478 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4479 specified, the former is passed to semihosting as it always 4480 takes precedence. 4481ERST 4482DEF("old-param", 0, QEMU_OPTION_old_param, 4483 "-old-param old param mode\n", QEMU_ARCH_ARM) 4484SRST 4485``-old-param`` 4486 Old param mode (ARM only). 4487ERST 4488 4489DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4490 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4491 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4492 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4493 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4494 " by the kernel, but typically no longer used by modern\n" \ 4495 " C library implementations.\n" \ 4496 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4497 " to elevate privileges using set*uid|gid system calls.\n" \ 4498 " The value 'children' will deny set*uid|gid system calls for\n" \ 4499 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4500 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4501 " blocking *fork and execve\n" \ 4502 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4503 QEMU_ARCH_ALL) 4504SRST 4505``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4506 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4507 filtering and 'off' will disable it. The default is 'off'. 4508 4509 ``obsolete=string`` 4510 Enable Obsolete system calls 4511 4512 ``elevateprivileges=string`` 4513 Disable set\*uid\|gid system calls 4514 4515 ``spawn=string`` 4516 Disable \*fork and execve 4517 4518 ``resourcecontrol=string`` 4519 Disable process affinity and schedular priority 4520ERST 4521 4522DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4523 "-readconfig <file>\n", QEMU_ARCH_ALL) 4524SRST 4525``-readconfig file`` 4526 Read device configuration from file. This approach is useful when 4527 you want to spawn QEMU process with many command line options but 4528 you don't want to exceed the command line character limit. 4529ERST 4530DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4531 "-writeconfig <file>\n" 4532 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4533SRST 4534ERST 4535 4536DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4537 "-no-user-config\n" 4538 " do not load default user-provided config files at startup\n", 4539 QEMU_ARCH_ALL) 4540SRST 4541``-no-user-config`` 4542 The ``-no-user-config`` option makes QEMU not load any of the 4543 user-provided config files on sysconfdir. 4544ERST 4545 4546DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4547 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4548 " specify tracing options\n", 4549 QEMU_ARCH_ALL) 4550SRST 4551``-trace [[enable=]pattern][,events=file][,file=file]`` 4552 .. include:: ../qemu-option-trace.rst.inc 4553 4554ERST 4555DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4556 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4557 " load a plugin\n", 4558 QEMU_ARCH_ALL) 4559SRST 4560``-plugin file=file[,argname=argvalue]`` 4561 Load a plugin. 4562 4563 ``file=file`` 4564 Load the given plugin from a shared library file. 4565 4566 ``argname=argvalue`` 4567 Argument passed to the plugin. (Can be given multiple times.) 4568ERST 4569 4570HXCOMM Internal use 4571DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4572DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4573 4574#ifdef __linux__ 4575DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4576 "-enable-fips enable FIPS 140-2 compliance\n", 4577 QEMU_ARCH_ALL) 4578#endif 4579SRST 4580``-enable-fips`` 4581 Enable FIPS 140-2 compliance mode. 4582ERST 4583 4584DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4585 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4586 " control error message format\n" 4587 " timestamp=on enables timestamps (default: off)\n" 4588 " guest-name=on enables guest name prefix but only if\n" 4589 " -name guest option is set (default: off)\n", 4590 QEMU_ARCH_ALL) 4591SRST 4592``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4593 Control error message format. 4594 4595 ``timestamp=on|off`` 4596 Prefix messages with a timestamp. Default is off. 4597 4598 ``guest-name=on|off`` 4599 Prefix messages with guest name but only if -name guest option is set 4600 otherwise the option is ignored. Default is off. 4601ERST 4602 4603DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4604 "-dump-vmstate <file>\n" 4605 " Output vmstate information in JSON format to file.\n" 4606 " Use the scripts/vmstate-static-checker.py file to\n" 4607 " check for possible regressions in migration code\n" 4608 " by comparing two such vmstate dumps.\n", 4609 QEMU_ARCH_ALL) 4610SRST 4611``-dump-vmstate file`` 4612 Dump json-encoded vmstate information for current machine type to 4613 file in file 4614ERST 4615 4616DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4617 "-enable-sync-profile\n" 4618 " enable synchronization profiling\n", 4619 QEMU_ARCH_ALL) 4620SRST 4621``-enable-sync-profile`` 4622 Enable synchronization profiling. 4623ERST 4624 4625DEFHEADING() 4626 4627DEFHEADING(Generic object creation:) 4628 4629DEF("object", HAS_ARG, QEMU_OPTION_object, 4630 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4631 " create a new object of type TYPENAME setting properties\n" 4632 " in the order they are specified. Note that the 'id'\n" 4633 " property must be set. These objects are placed in the\n" 4634 " '/objects' path.\n", 4635 QEMU_ARCH_ALL) 4636SRST 4637``-object typename[,prop1=value1,...]`` 4638 Create a new object of type typename setting properties in the order 4639 they are specified. Note that the 'id' property must be set. These 4640 objects are placed in the '/objects' path. 4641 4642 ``-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`` 4643 Creates a memory file backend object, which can be used to back 4644 the guest RAM with huge pages. 4645 4646 The ``id`` parameter is a unique ID that will be used to 4647 reference this memory region in other parameters, e.g. ``-numa``, 4648 ``-device nvdimm``, etc. 4649 4650 The ``size`` option provides the size of the memory region, and 4651 accepts common suffixes, e.g. ``500M``. 4652 4653 The ``mem-path`` provides the path to either a shared memory or 4654 huge page filesystem mount. 4655 4656 The ``share`` boolean option determines whether the memory 4657 region is marked as private to QEMU, or shared. The latter 4658 allows a co-operating external process to access the QEMU memory 4659 region. 4660 4661 The ``share`` is also required for pvrdma devices due to 4662 limitations in the RDMA API provided by Linux. 4663 4664 Setting share=on might affect the ability to configure NUMA 4665 bindings for the memory backend under some circumstances, see 4666 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4667 source tree for additional details. 4668 4669 Setting the ``discard-data`` boolean option to on indicates that 4670 file contents can be destroyed when QEMU exits, to avoid 4671 unnecessarily flushing data to the backing file. Note that 4672 ``discard-data`` is only an optimization, and QEMU might not 4673 discard file contents if it aborts unexpectedly or is terminated 4674 using SIGKILL. 4675 4676 The ``merge`` boolean option enables memory merge, also known as 4677 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4678 the pages for memory deduplication. 4679 4680 Setting the ``dump`` boolean option to off excludes the memory 4681 from core dumps. This feature is also known as MADV\_DONTDUMP. 4682 4683 The ``prealloc`` boolean option enables memory preallocation. 4684 4685 The ``host-nodes`` option binds the memory range to a list of 4686 NUMA host nodes. 4687 4688 The ``policy`` option sets the NUMA policy to one of the 4689 following values: 4690 4691 ``default`` 4692 default host policy 4693 4694 ``preferred`` 4695 prefer the given host node list for allocation 4696 4697 ``bind`` 4698 restrict memory allocation to the given host node list 4699 4700 ``interleave`` 4701 interleave memory allocations across the given host node 4702 list 4703 4704 The ``align`` option specifies the base address alignment when 4705 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4706 ``2M``. Some backend store specified by ``mem-path`` requires an 4707 alignment different than the default one used by QEMU, eg the 4708 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4709 such cases, users can specify the required alignment via this 4710 option. 4711 4712 The ``pmem`` option specifies whether the backing file specified 4713 by ``mem-path`` is in host persistent memory that can be 4714 accessed using the SNIA NVM programming model (e.g. Intel 4715 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4716 operations to guarantee the persistence of its own writes to 4717 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4718 migration). Also, we will map the backend-file with MAP\_SYNC 4719 flag, which ensures the file metadata is in sync for 4720 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4721 requires support from both the host kernel (since Linux kernel 4722 4.15) and the filesystem of ``mem-path`` mounted with DAX 4723 option. 4724 4725 The ``readonly`` option specifies whether the backing file is opened 4726 read-only or read-write (default). 4727 4728 ``-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`` 4729 Creates a memory backend object, which can be used to back the 4730 guest RAM. Memory backend objects offer more control than the 4731 ``-m`` option that is traditionally used to define guest RAM. 4732 Please refer to ``memory-backend-file`` for a description of the 4733 options. 4734 4735 ``-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`` 4736 Creates an anonymous memory file backend object, which allows 4737 QEMU to share the memory with an external process (e.g. when 4738 using vhost-user). The memory is allocated with memfd and 4739 optional sealing. (Linux only) 4740 4741 The ``seal`` option creates a sealed-file, that will block 4742 further resizing the memory ('on' by default). 4743 4744 The ``hugetlb`` option specify the file to be created resides in 4745 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4746 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4747 the hugetlb page size on systems that support multiple hugetlb 4748 page sizes (it must be a power of 2 value supported by the 4749 system). 4750 4751 In some versions of Linux, the ``hugetlb`` option is 4752 incompatible with the ``seal`` option (requires at least Linux 4753 4.16). 4754 4755 Please refer to ``memory-backend-file`` for a description of the 4756 other options. 4757 4758 The ``share`` boolean option is on by default with memfd. 4759 4760 ``-object rng-builtin,id=id`` 4761 Creates a random number generator backend which obtains entropy 4762 from QEMU builtin functions. The ``id`` parameter is a unique ID 4763 that will be used to reference this entropy backend from the 4764 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4765 uses this RNG backend. 4766 4767 ``-object rng-random,id=id,filename=/dev/random`` 4768 Creates a random number generator backend which obtains entropy 4769 from a device on the host. The ``id`` parameter is a unique ID 4770 that will be used to reference this entropy backend from the 4771 ``virtio-rng`` device. The ``filename`` parameter specifies 4772 which file to obtain entropy from and if omitted defaults to 4773 ``/dev/urandom``. 4774 4775 ``-object rng-egd,id=id,chardev=chardevid`` 4776 Creates a random number generator backend which obtains entropy 4777 from an external daemon running on the host. The ``id`` 4778 parameter is a unique ID that will be used to reference this 4779 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4780 parameter is the unique ID of a character device backend that 4781 provides the connection to the RNG daemon. 4782 4783 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4784 Creates a TLS anonymous credentials object, which can be used to 4785 provide TLS support on network backends. The ``id`` parameter is 4786 a unique ID which network backends will use to access the 4787 credentials. The ``endpoint`` is either ``server`` or ``client`` 4788 depending on whether the QEMU network backend that uses the 4789 credentials will be acting as a client or as a server. If 4790 ``verify-peer`` is enabled (the default) then once the handshake 4791 is completed, the peer credentials will be verified, though this 4792 is a no-op for anonymous credentials. 4793 4794 The dir parameter tells QEMU where to find the credential files. 4795 For server endpoints, this directory may contain a file 4796 dh-params.pem providing diffie-hellman parameters to use for the 4797 TLS server. If the file is missing, QEMU will generate a set of 4798 DH parameters at startup. This is a computationally expensive 4799 operation that consumes random pool entropy, so it is 4800 recommended that a persistent set of parameters be generated 4801 upfront and saved. 4802 4803 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4804 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4805 can be used to provide TLS support on network backends. The 4806 ``id`` parameter is a unique ID which network backends will use 4807 to access the credentials. The ``endpoint`` is either ``server`` 4808 or ``client`` depending on whether the QEMU network backend that 4809 uses the credentials will be acting as a client or as a server. 4810 For clients only, ``username`` is the username which will be 4811 sent to the server. If omitted it defaults to "qemu". 4812 4813 The dir parameter tells QEMU where to find the keys file. It is 4814 called "dir/keys.psk" and contains "username:key" pairs. This 4815 file can most easily be created using the GnuTLS ``psktool`` 4816 program. 4817 4818 For server endpoints, dir may also contain a file dh-params.pem 4819 providing diffie-hellman parameters to use for the TLS server. 4820 If the file is missing, QEMU will generate a set of DH 4821 parameters at startup. This is a computationally expensive 4822 operation that consumes random pool entropy, so it is 4823 recommended that a persistent set of parameters be generated up 4824 front and saved. 4825 4826 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4827 Creates a TLS anonymous credentials object, which can be used to 4828 provide TLS support on network backends. The ``id`` parameter is 4829 a unique ID which network backends will use to access the 4830 credentials. The ``endpoint`` is either ``server`` or ``client`` 4831 depending on whether the QEMU network backend that uses the 4832 credentials will be acting as a client or as a server. If 4833 ``verify-peer`` is enabled (the default) then once the handshake 4834 is completed, the peer credentials will be verified. With x509 4835 certificates, this implies that the clients must be provided 4836 with valid client certificates too. 4837 4838 The dir parameter tells QEMU where to find the credential files. 4839 For server endpoints, this directory may contain a file 4840 dh-params.pem providing diffie-hellman parameters to use for the 4841 TLS server. If the file is missing, QEMU will generate a set of 4842 DH parameters at startup. This is a computationally expensive 4843 operation that consumes random pool entropy, so it is 4844 recommended that a persistent set of parameters be generated 4845 upfront and saved. 4846 4847 For x509 certificate credentials the directory will contain 4848 further files providing the x509 certificates. The certificates 4849 must be stored in PEM format, in filenames ca-cert.pem, 4850 ca-crl.pem (optional), server-cert.pem (only servers), 4851 server-key.pem (only servers), client-cert.pem (only clients), 4852 and client-key.pem (only clients). 4853 4854 For the server-key.pem and client-key.pem files which contain 4855 sensitive private keys, it is possible to use an encrypted 4856 version by providing the passwordid parameter. This provides the 4857 ID of a previously created ``secret`` object containing the 4858 password for decryption. 4859 4860 The priority parameter allows to override the global default 4861 priority used by gnutls. This can be useful if the system 4862 administrator needs to use a weaker set of crypto priorities for 4863 QEMU without potentially forcing the weakness onto all 4864 applications. Or conversely if one wants wants a stronger 4865 default for QEMU than for all other applications, they can do 4866 this through this parameter. Its format is a gnutls priority 4867 string as described at 4868 https://gnutls.org/manual/html_node/Priority-Strings.html. 4869 4870 ``-object tls-cipher-suites,id=id,priority=priority`` 4871 Creates a TLS cipher suites object, which can be used to control 4872 the TLS cipher/protocol algorithms that applications are permitted 4873 to use. 4874 4875 The ``id`` parameter is a unique ID which frontends will use to 4876 access the ordered list of permitted TLS cipher suites from the 4877 host. 4878 4879 The ``priority`` parameter allows to override the global default 4880 priority used by gnutls. This can be useful if the system 4881 administrator needs to use a weaker set of crypto priorities for 4882 QEMU without potentially forcing the weakness onto all 4883 applications. Or conversely if one wants wants a stronger 4884 default for QEMU than for all other applications, they can do 4885 this through this parameter. Its format is a gnutls priority 4886 string as described at 4887 https://gnutls.org/manual/html_node/Priority-Strings.html. 4888 4889 An example of use of this object is to control UEFI HTTPS Boot. 4890 The tls-cipher-suites object exposes the ordered list of permitted 4891 TLS cipher suites from the host side to the guest firmware, via 4892 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4893 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4894 guest-side TLS. 4895 4896 In the following example, the priority at which the host-side policy 4897 is retrieved is given by the ``priority`` property. 4898 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4899 refer to /etc/crypto-policies/back-ends/gnutls.config. 4900 4901 .. parsed-literal:: 4902 4903 # |qemu_system| \\ 4904 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4905 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4906 4907 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4908 Interval t can't be 0, this filter batches the packet delivery: 4909 all packets arriving in a given interval on netdev netdevid are 4910 delayed until the end of the interval. Interval is in 4911 microseconds. ``status`` is optional that indicate whether the 4912 netfilter is on (enabled) or off (disabled), the default status 4913 for netfilter will be 'on'. 4914 4915 queue all\|rx\|tx is an option that can be applied to any 4916 netfilter. 4917 4918 ``all``: the filter is attached both to the receive and the 4919 transmit queue of the netdev (default). 4920 4921 ``rx``: the filter is attached to the receive queue of the 4922 netdev, where it will receive packets sent to the netdev. 4923 4924 ``tx``: the filter is attached to the transmit queue of the 4925 netdev, where it will receive packets sent by the netdev. 4926 4927 position head\|tail\|id=<id> is an option to specify where the 4928 filter should be inserted in the filter list. It can be applied 4929 to any netfilter. 4930 4931 ``head``: the filter is inserted at the head of the filter list, 4932 before any existing filters. 4933 4934 ``tail``: the filter is inserted at the tail of the filter list, 4935 behind any existing filters (default). 4936 4937 ``id=<id>``: the filter is inserted before or behind the filter 4938 specified by <id>, see the insert option below. 4939 4940 insert behind\|before is an option to specify where to insert 4941 the new filter relative to the one specified with 4942 position=id=<id>. It can be applied to any netfilter. 4943 4944 ``before``: insert before the specified filter. 4945 4946 ``behind``: insert behind the specified filter (default). 4947 4948 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4949 filter-mirror on netdev netdevid,mirror net packet to 4950 chardevchardevid, if it has the vnet\_hdr\_support flag, 4951 filter-mirror will mirror packet with vnet\_hdr\_len. 4952 4953 ``-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]`` 4954 filter-redirector on netdev netdevid,redirect filter's net 4955 packet to chardev chardevid,and redirect indev's packet to 4956 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4957 will redirect packet with vnet\_hdr\_len. Create a 4958 filter-redirector we need to differ outdev id from indev id, id 4959 can not be the same. we can just use indev or outdev, but at 4960 least one of indev or outdev need to be specified. 4961 4962 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4963 Filter-rewriter is a part of COLO project.It will rewrite tcp 4964 packet to secondary from primary to keep secondary tcp 4965 connection,and rewrite tcp packet to primary from secondary make 4966 tcp packet can be handled by client.if it has the 4967 vnet\_hdr\_support flag, we can parse packet with vnet header. 4968 4969 usage: colo secondary: -object 4970 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4971 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4972 filter-rewriter,id=rew0,netdev=hn0,queue=all 4973 4974 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4975 Dump the network traffic on netdev dev to the file specified by 4976 filename. At most len bytes (64k by default) per packet are 4977 stored. The file format is libpcap, so it can be analyzed with 4978 tools such as tcpdump or Wireshark. 4979 4980 ``-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}]`` 4981 Colo-compare gets packet from primary\_in chardevid and 4982 secondary\_in, then compare whether the payload of primary packet 4983 and secondary packet are the same. If same, it will output 4984 primary packet to out\_dev, else it will notify COLO-framework to do 4985 checkpoint and send primary packet to out\_dev. In order to 4986 improve efficiency, we need to put the task of comparison in 4987 another iothread. If it has the vnet\_hdr\_support flag, 4988 colo compare will send/recv packet with vnet\_hdr\_len. 4989 The compare\_timeout=@var{ms} determines the maximum time of the 4990 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4991 is to set the period of scanning expired primary node network packets. 4992 The max\_queue\_size=@var{size} is to set the max compare queue 4993 size depend on user environment. 4994 If user want to use Xen COLO, need to add the notify\_dev to 4995 notify Xen colo-frame to do checkpoint. 4996 4997 COLO-compare must be used with the help of filter-mirror, 4998 filter-redirector and filter-rewriter. 4999 5000 :: 5001 5002 KVM COLO 5003 5004 primary: 5005 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5006 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5007 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5008 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5009 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5010 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5011 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5012 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5013 -object iothread,id=iothread1 5014 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5015 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5016 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5017 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5018 5019 secondary: 5020 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5021 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5022 -chardev socket,id=red0,host=3.3.3.3,port=9003 5023 -chardev socket,id=red1,host=3.3.3.3,port=9004 5024 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5025 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5026 5027 5028 Xen COLO 5029 5030 primary: 5031 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5032 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5033 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5034 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5035 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5036 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5037 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5038 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5039 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5040 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5041 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5042 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5043 -object iothread,id=iothread1 5044 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5045 5046 secondary: 5047 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5048 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5049 -chardev socket,id=red0,host=3.3.3.3,port=9003 5050 -chardev socket,id=red1,host=3.3.3.3,port=9004 5051 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5052 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5053 5054 If you want to know the detail of above command line, you can 5055 read the colo-compare git log. 5056 5057 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5058 Creates a cryptodev backend which executes crypto opreation from 5059 the QEMU cipher APIS. The id parameter is a unique ID that will 5060 be used to reference this cryptodev backend from the 5061 ``virtio-crypto`` device. The queues parameter is optional, 5062 which specify the queue number of cryptodev backend, the default 5063 of queues is 1. 5064 5065 .. parsed-literal:: 5066 5067 # |qemu_system| \\ 5068 [...] \\ 5069 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5070 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5071 [...] 5072 5073 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5074 Creates a vhost-user cryptodev backend, backed by a chardev 5075 chardevid. The id parameter is a unique ID that will be used to 5076 reference this cryptodev backend from the ``virtio-crypto`` 5077 device. The chardev should be a unix domain socket backed one. 5078 The vhost-user uses a specifically defined protocol to pass 5079 vhost ioctl replacement messages to an application on the other 5080 end of the socket. The queues parameter is optional, which 5081 specify the queue number of cryptodev backend for multiqueue 5082 vhost-user, the default of queues is 1. 5083 5084 .. parsed-literal:: 5085 5086 # |qemu_system| \\ 5087 [...] \\ 5088 -chardev socket,id=chardev0,path=/path/to/socket \\ 5089 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5090 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5091 [...] 5092 5093 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5094 \ 5095 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5096 Defines a secret to store a password, encryption key, or some 5097 other sensitive data. The sensitive data can either be passed 5098 directly via the data parameter, or indirectly via the file 5099 parameter. Using the data parameter is insecure unless the 5100 sensitive data is encrypted. 5101 5102 The sensitive data can be provided in raw format (the default), 5103 or base64. When encoded as JSON, the raw format only supports 5104 valid UTF-8 characters, so base64 is recommended for sending 5105 binary data. QEMU will convert from which ever format is 5106 provided to the format it needs internally. eg, an RBD password 5107 can be provided in raw format, even though it will be base64 5108 encoded when passed onto the RBD sever. 5109 5110 For added protection, it is possible to encrypt the data 5111 associated with a secret using the AES-256-CBC cipher. Use of 5112 encryption is indicated by providing the keyid and iv 5113 parameters. The keyid parameter provides the ID of a previously 5114 defined secret that contains the AES-256 decryption key. This 5115 key should be 32-bytes long and be base64 encoded. The iv 5116 parameter provides the random initialization vector used for 5117 encryption of this particular secret and should be a base64 5118 encrypted string of the 16-byte IV. 5119 5120 The simplest (insecure) usage is to provide the secret inline 5121 5122 .. parsed-literal:: 5123 5124 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5125 5126 The simplest secure usage is to provide the secret via a file 5127 5128 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5129 secret,id=sec0,file=mypasswd.txt,format=raw 5130 5131 For greater security, AES-256-CBC should be used. To illustrate 5132 usage, consider the openssl command line tool which can encrypt 5133 the data. Note that when encrypting, the plaintext must be 5134 padded to the cipher block size (32 bytes) using the standard 5135 PKCS#5/6 compatible padding algorithm. 5136 5137 First a master key needs to be created in base64 encoding: 5138 5139 :: 5140 5141 # openssl rand -base64 32 > key.b64 5142 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5143 5144 Each secret to be encrypted needs to have a random 5145 initialization vector generated. These do not need to be kept 5146 secret 5147 5148 :: 5149 5150 # openssl rand -base64 16 > iv.b64 5151 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5152 5153 The secret to be defined can now be encrypted, in this case 5154 we're telling openssl to base64 encode the result, but it could 5155 be left as raw bytes if desired. 5156 5157 :: 5158 5159 # SECRET=$(printf "letmein" | 5160 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5161 5162 When launching QEMU, create a master secret pointing to 5163 ``key.b64`` and specify that to be used to decrypt the user 5164 password. Pass the contents of ``iv.b64`` to the second secret 5165 5166 .. parsed-literal:: 5167 5168 # |qemu_system| \\ 5169 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5170 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5171 data=$SECRET,iv=$(<iv.b64) 5172 5173 ``-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]`` 5174 Create a Secure Encrypted Virtualization (SEV) guest object, 5175 which can be used to provide the guest memory encryption support 5176 on AMD processors. 5177 5178 When memory encryption is enabled, one of the physical address 5179 bit (aka the C-bit) is utilized to mark if a memory page is 5180 protected. The ``cbitpos`` is used to provide the C-bit 5181 position. The C-bit position is Host family dependent hence user 5182 must provide this value. On EPYC, the value should be 47. 5183 5184 When memory encryption is enabled, we loose certain bits in 5185 physical address space. The ``reduced-phys-bits`` is used to 5186 provide the number of bits we loose in physical address space. 5187 Similar to C-bit, the value is Host family dependent. On EPYC, 5188 the value should be 5. 5189 5190 The ``sev-device`` provides the device file to use for 5191 communicating with the SEV firmware running inside AMD Secure 5192 Processor. The default device is '/dev/sev'. If hardware 5193 supports memory encryption then /dev/sev devices are created by 5194 CCP driver. 5195 5196 The ``policy`` provides the guest policy to be enforced by the 5197 SEV firmware and restrict what configuration and operational 5198 commands can be performed on this guest by the hypervisor. The 5199 policy should be provided by the guest owner and is bound to the 5200 guest and cannot be changed throughout the lifetime of the 5201 guest. The default is 0. 5202 5203 If guest ``policy`` allows sharing the key with another SEV 5204 guest then ``handle`` can be use to provide handle of the guest 5205 from which to share the key. 5206 5207 The ``dh-cert-file`` and ``session-file`` provides the guest 5208 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5209 and session parameters are used for establishing a cryptographic 5210 session with the guest owner to negotiate keys used for 5211 attestation. The file must be encoded in base64. 5212 5213 e.g to launch a SEV guest 5214 5215 .. parsed-literal:: 5216 5217 # |qemu_system_x86| \\ 5218 ...... \\ 5219 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5220 -machine ...,memory-encryption=sev0 \\ 5221 ..... 5222 5223 ``-object authz-simple,id=id,identity=string`` 5224 Create an authorization object that will control access to 5225 network services. 5226 5227 The ``identity`` parameter is identifies the user and its format 5228 depends on the network service that authorization object is 5229 associated with. For authorizing based on TLS x509 certificates, 5230 the identity must be the x509 distinguished name. Note that care 5231 must be taken to escape any commas in the distinguished name. 5232 5233 An example authorization object to validate a x509 distinguished 5234 name would look like: 5235 5236 .. parsed-literal:: 5237 5238 # |qemu_system| \\ 5239 ... \\ 5240 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5241 ... 5242 5243 Note the use of quotes due to the x509 distinguished name 5244 containing whitespace, and escaping of ','. 5245 5246 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5247 Create an authorization object that will control access to 5248 network services. 5249 5250 The ``filename`` parameter is the fully qualified path to a file 5251 containing the access control list rules in JSON format. 5252 5253 An example set of rules that match against SASL usernames might 5254 look like: 5255 5256 :: 5257 5258 { 5259 "rules": [ 5260 { "match": "fred", "policy": "allow", "format": "exact" }, 5261 { "match": "bob", "policy": "allow", "format": "exact" }, 5262 { "match": "danb", "policy": "deny", "format": "glob" }, 5263 { "match": "dan*", "policy": "allow", "format": "exact" }, 5264 ], 5265 "policy": "deny" 5266 } 5267 5268 When checking access the object will iterate over all the rules 5269 and the first rule to match will have its ``policy`` value 5270 returned as the result. If no rules match, then the default 5271 ``policy`` value is returned. 5272 5273 The rules can either be an exact string match, or they can use 5274 the simple UNIX glob pattern matching to allow wildcards to be 5275 used. 5276 5277 If ``refresh`` is set to true the file will be monitored and 5278 automatically reloaded whenever its content changes. 5279 5280 As with the ``authz-simple`` object, the format of the identity 5281 strings being matched depends on the network service, but is 5282 usually a TLS x509 distinguished name, or a SASL username. 5283 5284 An example authorization object to validate a SASL username 5285 would look like: 5286 5287 .. parsed-literal:: 5288 5289 # |qemu_system| \\ 5290 ... \\ 5291 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5292 ... 5293 5294 ``-object authz-pam,id=id,service=string`` 5295 Create an authorization object that will control access to 5296 network services. 5297 5298 The ``service`` parameter provides the name of a PAM service to 5299 use for authorization. It requires that a file 5300 ``/etc/pam.d/service`` exist to provide the configuration for 5301 the ``account`` subsystem. 5302 5303 An example authorization object to validate a TLS x509 5304 distinguished name would look like: 5305 5306 .. parsed-literal:: 5307 5308 # |qemu_system| \\ 5309 ... \\ 5310 -object authz-pam,id=auth0,service=qemu-vnc \\ 5311 ... 5312 5313 There would then be a corresponding config file for PAM at 5314 ``/etc/pam.d/qemu-vnc`` that contains: 5315 5316 :: 5317 5318 account requisite pam_listfile.so item=user sense=allow \ 5319 file=/etc/qemu/vnc.allow 5320 5321 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5322 of x509 distingished names that are permitted access 5323 5324 :: 5325 5326 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5327 5328 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5329 Creates a dedicated event loop thread that devices can be 5330 assigned to. This is known as an IOThread. By default device 5331 emulation happens in vCPU threads or the main event loop thread. 5332 This can become a scalability bottleneck. IOThreads allow device 5333 emulation and I/O to run on other host CPUs. 5334 5335 The ``id`` parameter is a unique ID that will be used to 5336 reference this IOThread from ``-device ...,iothread=id``. 5337 Multiple devices can be assigned to an IOThread. Note that not 5338 all devices support an ``iothread`` parameter. 5339 5340 The ``query-iothreads`` QMP command lists IOThreads and reports 5341 their thread IDs so that the user can configure host CPU 5342 pinning/affinity. 5343 5344 IOThreads use an adaptive polling algorithm to reduce event loop 5345 latency. Instead of entering a blocking system call to monitor 5346 file descriptors and then pay the cost of being woken up when an 5347 event occurs, the polling algorithm spins waiting for events for 5348 a short time. The algorithm's default parameters are suitable 5349 for many cases but can be adjusted based on knowledge of the 5350 workload and/or host device latency. 5351 5352 The ``poll-max-ns`` parameter is the maximum number of 5353 nanoseconds to busy wait for events. Polling can be disabled by 5354 setting this value to 0. 5355 5356 The ``poll-grow`` parameter is the multiplier used to increase 5357 the polling time when the algorithm detects it is missing events 5358 due to not polling long enough. 5359 5360 The ``poll-shrink`` parameter is the divisor used to decrease 5361 the polling time when the algorithm detects it is spending too 5362 long polling without encountering events. 5363 5364 The ``aio-max-batch`` parameter is the maximum number of requests 5365 in a batch for the AIO engine, 0 means that the engine will use 5366 its default. 5367 5368 The IOThread parameters can be modified at run-time using the 5369 ``qom-set`` command (where ``iothread1`` is the IOThread's 5370 ``id``): 5371 5372 :: 5373 5374 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5375ERST 5376 5377 5378HXCOMM This is the last statement. Insert new options before this line! 5379 5380#undef DEF 5381#undef DEFHEADING 5382#undef ARCHHEADING 5383
