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,sgx-epc.0.node=numaid\n", 131 QEMU_ARCH_ALL) 132 133SRST 134``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 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=maxcpus][,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. Prior to 6.2 the preference was sockets over cores 248 over threads. Since 6.2 the preference is cores over sockets over threads. 249ERST 250 251DEF("numa", HAS_ARG, QEMU_OPTION_numa, 252 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 253 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 254 "-numa dist,src=source,dst=destination,val=distance\n" 255 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 256 "-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" 257 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 258 QEMU_ARCH_ALL) 259SRST 260``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 261 \ 262``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 263 \ 264``-numa dist,src=source,dst=destination,val=distance`` 265 \ 266``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 267 \ 268``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 269 \ 270``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 271 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 272 distance from a source node to a destination node. Set the ACPI 273 Heterogeneous Memory Attributes for the given nodes. 274 275 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 276 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 277 contiguous range of CPU indexes (or a single VCPU if lastcpu is 278 omitted). A non-contiguous set of VCPUs can be represented by 279 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 280 omitted on all nodes, VCPUs are automatically split between them. 281 282 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 283 NUMA node: 284 285 :: 286 287 -numa node,cpus=0-2,cpus=5 288 289 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 290 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 291 assign CPU objects to a node using topology layout properties of 292 CPU. The set of properties is machine specific, and depends on used 293 machine type/'\ ``smp``\ ' options. It could be queried with 294 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 295 property specifies node to which CPU object will be assigned, it's 296 required for node to be declared with '\ ``node``\ ' option before 297 it's used with '\ ``cpu``\ ' option. 298 299 For example: 300 301 :: 302 303 -M pc \ 304 -smp 1,sockets=2,maxcpus=2 \ 305 -numa node,nodeid=0 -numa node,nodeid=1 \ 306 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 307 308 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 309 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 310 a given memory backend device to a node. If '\ ``mem``\ ' and 311 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 312 313 314 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 315 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 316 use it. 317 318 '\ ``initiator``\ ' is an additional option that points to an 319 initiator NUMA node that has best performance (the lowest latency or 320 largest bandwidth) to this NUMA node. Note that this option can be 321 set only when the machine property 'hmat' is set to 'on'. 322 323 Following example creates a machine with 2 NUMA nodes, node 0 has 324 CPU. node 1 has only memory, and its initiator is node 0. Note that 325 because node 0 has CPU, by default the initiator of node 0 is itself 326 and must be itself. 327 328 :: 329 330 -machine hmat=on \ 331 -m 2G,slots=2,maxmem=4G \ 332 -object memory-backend-ram,size=1G,id=m0 \ 333 -object memory-backend-ram,size=1G,id=m1 \ 334 -numa node,nodeid=0,memdev=m0 \ 335 -numa node,nodeid=1,memdev=m1,initiator=0 \ 336 -smp 2,sockets=2,maxcpus=2 \ 337 -numa cpu,node-id=0,socket-id=0 \ 338 -numa cpu,node-id=0,socket-id=1 339 340 source and destination are NUMA node IDs. distance is the NUMA 341 distance from source to destination. The distance from a node to 342 itself is always 10. If any pair of nodes is given a distance, then 343 all pairs must be given distances. Although, when distances are only 344 given in one direction for each pair of nodes, then the distances in 345 the opposite directions are assumed to be the same. If, however, an 346 asymmetrical pair of distances is given for even one node pair, then 347 all node pairs must be provided distance values for both directions, 348 even when they are symmetrical. When a node is unreachable from 349 another node, set the pair's distance to 255. 350 351 Note that the -``numa`` option doesn't allocate any of the specified 352 resources, it just assigns existing resources to NUMA nodes. This 353 means that one still has to use the ``-m``, ``-smp`` options to 354 allocate RAM and VCPUs respectively. 355 356 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 357 Information between initiator and target NUMA nodes in ACPI 358 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 359 create memory requests, usually it has one or more processors. 360 Target NUMA node contains addressable memory. 361 362 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 363 the memory hierarchy of the target NUMA node: if hierarchy is 364 'memory', the structure represents the memory performance; if 365 hierarchy is 'first-level\|second-level\|third-level', this 366 structure represents aggregated performance of memory side caches 367 for each domain. type of 'data-type' is type of data represented by 368 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 369 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 370 the target memory; if 'hierarchy' is 371 'first-level\|second-level\|third-level', 'data-type' is 372 'access\|read\|write' hit latency or 'access\|read\|write' hit 373 bandwidth of the target memory side cache. 374 375 lat is latency value in nanoseconds. bw is bandwidth value, the 376 possible value and units are NUM[M\|G\|T], mean that the bandwidth 377 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 378 used suffix). Note that if latency or bandwidth value is 0, means 379 the corresponding latency or bandwidth information is not provided. 380 381 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 382 belongs. size is the size of memory side cache in bytes. level is 383 the cache level described in this structure, note that the cache 384 level 0 should not be used with '\ ``hmat-cache``\ ' option. 385 associativity is the cache associativity, the possible value is 386 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 387 is the write policy. line is the cache Line size in bytes. 388 389 For example, the following options describe 2 NUMA nodes. Node 0 has 390 2 cpus and a ram, node 1 has only a ram. The processors in node 0 391 access memory in node 0 with access-latency 5 nanoseconds, 392 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 393 memory in NUMA node 1 with access-latency 10 nanoseconds, 394 access-bandwidth is 100 MB/s. And for memory side cache information, 395 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 396 policy is write-back, the cache Line size is 8 bytes: 397 398 :: 399 400 -machine hmat=on \ 401 -m 2G \ 402 -object memory-backend-ram,size=1G,id=m0 \ 403 -object memory-backend-ram,size=1G,id=m1 \ 404 -smp 2,sockets=2,maxcpus=2 \ 405 -numa node,nodeid=0,memdev=m0 \ 406 -numa node,nodeid=1,memdev=m1,initiator=0 \ 407 -numa cpu,node-id=0,socket-id=0 \ 408 -numa cpu,node-id=0,socket-id=1 \ 409 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 410 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 411 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 412 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 413 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 414 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 415ERST 416 417DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 418 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 419 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 420SRST 421``-add-fd fd=fd,set=set[,opaque=opaque]`` 422 Add a file descriptor to an fd set. Valid options are: 423 424 ``fd=fd`` 425 This option defines the file descriptor of which a duplicate is 426 added to fd set. The file descriptor cannot be stdin, stdout, or 427 stderr. 428 429 ``set=set`` 430 This option defines the ID of the fd set to add the file 431 descriptor to. 432 433 ``opaque=opaque`` 434 This option defines a free-form string that can be used to 435 describe fd. 436 437 You can open an image using pre-opened file descriptors from an fd 438 set: 439 440 .. parsed-literal:: 441 442 |qemu_system| \\ 443 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 444 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 445 -drive file=/dev/fdset/2,index=0,media=disk 446ERST 447 448DEF("set", HAS_ARG, QEMU_OPTION_set, 449 "-set group.id.arg=value\n" 450 " set <arg> parameter for item <id> of type <group>\n" 451 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 452SRST 453``-set group.id.arg=value`` 454 Set parameter arg for item id of type group 455ERST 456 457DEF("global", HAS_ARG, QEMU_OPTION_global, 458 "-global driver.property=value\n" 459 "-global driver=driver,property=property,value=value\n" 460 " set a global default for a driver property\n", 461 QEMU_ARCH_ALL) 462SRST 463``-global driver.prop=value`` 464 \ 465``-global driver=driver,property=property,value=value`` 466 Set default value of driver's property prop to value, e.g.: 467 468 .. parsed-literal:: 469 470 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 471 472 In particular, you can use this to set driver properties for devices 473 which are created automatically by the machine model. To create a 474 device which is not created automatically and set properties on it, 475 use -``device``. 476 477 -global driver.prop=value is shorthand for -global 478 driver=driver,property=prop,value=value. The longhand syntax works 479 even when driver contains a dot. 480ERST 481 482DEF("boot", HAS_ARG, QEMU_OPTION_boot, 483 "-boot [order=drives][,once=drives][,menu=on|off]\n" 484 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 485 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 486 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 487 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 488 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 489 QEMU_ARCH_ALL) 490SRST 491``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 492 Specify boot order drives as a string of drive letters. Valid drive 493 letters depend on the target architecture. The x86 PC uses: a, b 494 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 495 (Etherboot from network adapter 1-4), hard disk boot is the default. 496 To apply a particular boot order only on the first startup, specify 497 it via ``once``. Note that the ``order`` or ``once`` parameter 498 should not be used together with the ``bootindex`` property of 499 devices, since the firmware implementations normally do not support 500 both at the same time. 501 502 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 503 as firmware/BIOS supports them. The default is non-interactive boot. 504 505 A splash picture could be passed to bios, enabling user to show it 506 as logo, when option splash=sp\_name is given and menu=on, If 507 firmware/BIOS supports them. Currently Seabios for X86 system 508 support it. limitation: The splash file could be a jpeg file or a 509 BMP file in 24 BPP format(true color). The resolution should be 510 supported by the SVGA mode, so the recommended is 320x240, 640x480, 511 800x640. 512 513 A timeout could be passed to bios, guest will pause for rb\_timeout 514 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 515 not reboot, qemu passes '-1' to bios by default. Currently Seabios 516 for X86 system support it. 517 518 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 519 it. This only effects when boot priority is changed by bootindex 520 options. The default is non-strict boot. 521 522 .. parsed-literal:: 523 524 # try to boot from network first, then from hard disk 525 |qemu_system_x86| -boot order=nc 526 # boot from CD-ROM first, switch back to default order after reboot 527 |qemu_system_x86| -boot once=d 528 # boot with a splash picture for 5 seconds. 529 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 530 531 Note: The legacy format '-boot drives' is still supported but its 532 use is discouraged as it may be removed from future versions. 533ERST 534 535DEF("m", HAS_ARG, QEMU_OPTION_m, 536 "-m [size=]megs[,slots=n,maxmem=size]\n" 537 " configure guest RAM\n" 538 " size: initial amount of guest memory\n" 539 " slots: number of hotplug slots (default: none)\n" 540 " maxmem: maximum amount of guest memory (default: none)\n" 541 "NOTE: Some architectures might enforce a specific granularity\n", 542 QEMU_ARCH_ALL) 543SRST 544``-m [size=]megs[,slots=n,maxmem=size]`` 545 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 546 Optionally, a suffix of "M" or "G" can be used to signify a value in 547 megabytes or gigabytes respectively. Optional pair slots, maxmem 548 could be used to set amount of hotpluggable memory slots and maximum 549 amount of memory. Note that maxmem must be aligned to the page size. 550 551 For example, the following command-line sets the guest startup RAM 552 size to 1GB, creates 3 slots to hotplug additional memory and sets 553 the maximum memory the guest can reach to 4GB: 554 555 .. parsed-literal:: 556 557 |qemu_system| -m 1G,slots=3,maxmem=4G 558 559 If slots and maxmem are not specified, memory hotplug won't be 560 enabled and the guest startup RAM will never increase. 561ERST 562 563DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 564 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 565SRST 566``-mem-path path`` 567 Allocate guest RAM from a temporarily created file in path. 568ERST 569 570DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 571 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 572 QEMU_ARCH_ALL) 573SRST 574``-mem-prealloc`` 575 Preallocate memory when using -mem-path. 576ERST 577 578DEF("k", HAS_ARG, QEMU_OPTION_k, 579 "-k language use keyboard layout (for example 'fr' for French)\n", 580 QEMU_ARCH_ALL) 581SRST 582``-k language`` 583 Use keyboard layout language (for example ``fr`` for French). This 584 option is only needed where it is not easy to get raw PC keycodes 585 (e.g. on Macs, with some X11 servers or with a VNC or curses 586 display). You don't normally need to use it on PC/Linux or 587 PC/Windows hosts. 588 589 The available layouts are: 590 591 :: 592 593 ar de-ch es fo fr-ca hu ja mk no pt-br sv 594 da en-gb et fr fr-ch is lt nl pl ru th 595 de en-us fi fr-be hr it lv nl-be pt sl tr 596 597 The default is ``en-us``. 598ERST 599 600 601HXCOMM Deprecated by -audiodev 602DEF("audio-help", 0, QEMU_OPTION_audio_help, 603 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 604 QEMU_ARCH_ALL) 605SRST 606``-audio-help`` 607 Will show the -audiodev equivalent of the currently specified 608 (deprecated) environment variables. 609ERST 610 611DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 612 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 613 " specifies the audio backend to use\n" 614 " id= identifier of the backend\n" 615 " timer-period= timer period in microseconds\n" 616 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 617 " in|out.fixed-settings= use fixed settings for host audio\n" 618 " in|out.frequency= frequency to use with fixed settings\n" 619 " in|out.channels= number of channels to use with fixed settings\n" 620 " in|out.format= sample format to use with fixed settings\n" 621 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 622 " in|out.voices= number of voices to use\n" 623 " in|out.buffer-length= length of buffer in microseconds\n" 624 "-audiodev none,id=id,[,prop[=value][,...]]\n" 625 " dummy driver that discards all output\n" 626#ifdef CONFIG_AUDIO_ALSA 627 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 628 " in|out.dev= name of the audio device to use\n" 629 " in|out.period-length= length of period in microseconds\n" 630 " in|out.try-poll= attempt to use poll mode\n" 631 " threshold= threshold (in microseconds) when playback starts\n" 632#endif 633#ifdef CONFIG_AUDIO_COREAUDIO 634 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 635 " in|out.buffer-count= number of buffers\n" 636#endif 637#ifdef CONFIG_AUDIO_DSOUND 638 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 639 " latency= add extra latency to playback in microseconds\n" 640#endif 641#ifdef CONFIG_AUDIO_OSS 642 "-audiodev oss,id=id[,prop[=value][,...]]\n" 643 " in|out.dev= path of the audio device to use\n" 644 " in|out.buffer-count= number of buffers\n" 645 " in|out.try-poll= attempt to use poll mode\n" 646 " try-mmap= try using memory mapped access\n" 647 " exclusive= open device in exclusive mode\n" 648 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 649#endif 650#ifdef CONFIG_AUDIO_PA 651 "-audiodev pa,id=id[,prop[=value][,...]]\n" 652 " server= PulseAudio server address\n" 653 " in|out.name= source/sink device name\n" 654 " in|out.latency= desired latency in microseconds\n" 655#endif 656#ifdef CONFIG_AUDIO_SDL 657 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 658 " in|out.buffer-count= number of buffers\n" 659#endif 660#ifdef CONFIG_SPICE 661 "-audiodev spice,id=id[,prop[=value][,...]]\n" 662#endif 663#ifdef CONFIG_DBUS_DISPLAY 664 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 665#endif 666 "-audiodev wav,id=id[,prop[=value][,...]]\n" 667 " path= path of wav file to record\n", 668 QEMU_ARCH_ALL) 669SRST 670``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 671 Adds a new audio backend driver identified by id. There are global 672 and driver specific properties. Some values can be set differently 673 for input and output, they're marked with ``in|out.``. You can set 674 the input's property with ``in.prop`` and the output's property with 675 ``out.prop``. For example: 676 677 :: 678 679 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 680 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 681 682 NOTE: parameter validation is known to be incomplete, in many cases 683 specifying an invalid option causes QEMU to print an error message 684 and continue emulation without sound. 685 686 Valid global options are: 687 688 ``id=identifier`` 689 Identifies the audio backend. 690 691 ``timer-period=period`` 692 Sets the timer period used by the audio subsystem in 693 microseconds. Default is 10000 (10 ms). 694 695 ``in|out.mixing-engine=on|off`` 696 Use QEMU's mixing engine to mix all streams inside QEMU and 697 convert audio formats when not supported by the backend. When 698 off, fixed-settings must be off too. Note that disabling this 699 option means that the selected backend must support multiple 700 streams and the audio formats used by the virtual cards, 701 otherwise you'll get no sound. It's not recommended to disable 702 this option unless you want to use 5.1 or 7.1 audio, as mixing 703 engine only supports mono and stereo audio. Default is on. 704 705 ``in|out.fixed-settings=on|off`` 706 Use fixed settings for host audio. When off, it will change 707 based on how the guest opens the sound card. In this case you 708 must not specify frequency, channels or format. Default is on. 709 710 ``in|out.frequency=frequency`` 711 Specify the frequency to use when using fixed-settings. Default 712 is 44100Hz. 713 714 ``in|out.channels=channels`` 715 Specify the number of channels to use when using fixed-settings. 716 Default is 2 (stereo). 717 718 ``in|out.format=format`` 719 Specify the sample format to use when using fixed-settings. 720 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 721 ``u32``, ``f32``. Default is ``s16``. 722 723 ``in|out.voices=voices`` 724 Specify the number of voices to use. Default is 1. 725 726 ``in|out.buffer-length=usecs`` 727 Sets the size of the buffer in microseconds. 728 729``-audiodev none,id=id[,prop[=value][,...]]`` 730 Creates a dummy backend that discards all outputs. This backend has 731 no backend specific properties. 732 733``-audiodev alsa,id=id[,prop[=value][,...]]`` 734 Creates backend using the ALSA. This backend is only available on 735 Linux. 736 737 ALSA specific options are: 738 739 ``in|out.dev=device`` 740 Specify the ALSA device to use for input and/or output. Default 741 is ``default``. 742 743 ``in|out.period-length=usecs`` 744 Sets the period length in microseconds. 745 746 ``in|out.try-poll=on|off`` 747 Attempt to use poll mode with the device. Default is on. 748 749 ``threshold=threshold`` 750 Threshold (in microseconds) when playback starts. Default is 0. 751 752``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 753 Creates a backend using Apple's Core Audio. This backend is only 754 available on Mac OS and only supports playback. 755 756 Core Audio specific options are: 757 758 ``in|out.buffer-count=count`` 759 Sets the count of the buffers. 760 761``-audiodev dsound,id=id[,prop[=value][,...]]`` 762 Creates a backend using Microsoft's DirectSound. This backend is 763 only available on Windows and only supports playback. 764 765 DirectSound specific options are: 766 767 ``latency=usecs`` 768 Add extra usecs microseconds latency to playback. Default is 769 10000 (10 ms). 770 771``-audiodev oss,id=id[,prop[=value][,...]]`` 772 Creates a backend using OSS. This backend is available on most 773 Unix-like systems. 774 775 OSS specific options are: 776 777 ``in|out.dev=device`` 778 Specify the file name of the OSS device to use. Default is 779 ``/dev/dsp``. 780 781 ``in|out.buffer-count=count`` 782 Sets the count of the buffers. 783 784 ``in|out.try-poll=on|of`` 785 Attempt to use poll mode with the device. Default is on. 786 787 ``try-mmap=on|off`` 788 Try using memory mapped device access. Default is off. 789 790 ``exclusive=on|off`` 791 Open the device in exclusive mode (vmix won't work in this 792 case). Default is off. 793 794 ``dsp-policy=policy`` 795 Sets the timing policy (between 0 and 10, where smaller number 796 means smaller latency but higher CPU usage). Use -1 to use 797 buffer sizes specified by ``buffer`` and ``buffer-count``. This 798 option is ignored if you do not have OSS 4. Default is 5. 799 800``-audiodev pa,id=id[,prop[=value][,...]]`` 801 Creates a backend using PulseAudio. This backend is available on 802 most systems. 803 804 PulseAudio specific options are: 805 806 ``server=server`` 807 Sets the PulseAudio server to connect to. 808 809 ``in|out.name=sink`` 810 Use the specified source/sink for recording/playback. 811 812 ``in|out.latency=usecs`` 813 Desired latency in microseconds. The PulseAudio server will try 814 to honor this value but actual latencies may be lower or higher. 815 816``-audiodev sdl,id=id[,prop[=value][,...]]`` 817 Creates a backend using SDL. This backend is available on most 818 systems, but you should use your platform's native backend if 819 possible. 820 821 SDL specific options are: 822 823 ``in|out.buffer-count=count`` 824 Sets the count of the buffers. 825 826``-audiodev spice,id=id[,prop[=value][,...]]`` 827 Creates a backend that sends audio through SPICE. This backend 828 requires ``-spice`` and automatically selected in that case, so 829 usually you can ignore this option. This backend has no backend 830 specific properties. 831 832``-audiodev wav,id=id[,prop[=value][,...]]`` 833 Creates a backend that writes audio to a WAV file. 834 835 Backend specific options are: 836 837 ``path=path`` 838 Write recorded audio into the specified file. Default is 839 ``qemu.wav``. 840ERST 841 842DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 843 "-soundhw c1,... enable audio support\n" 844 " and only specified sound cards (comma separated list)\n" 845 " use '-soundhw help' to get the list of supported cards\n" 846 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 847SRST 848``-soundhw card1[,card2,...] or -soundhw all`` 849 Enable audio and selected sound hardware. Use 'help' to print all 850 available sound hardware. For example: 851 852 .. parsed-literal:: 853 854 |qemu_system_x86| -soundhw sb16,adlib disk.img 855 |qemu_system_x86| -soundhw es1370 disk.img 856 |qemu_system_x86| -soundhw ac97 disk.img 857 |qemu_system_x86| -soundhw hda disk.img 858 |qemu_system_x86| -soundhw all disk.img 859 |qemu_system_x86| -soundhw help 860 861 Note that Linux's i810\_audio OSS kernel (for AC97) module might 862 require manually specifying clocking. 863 864 :: 865 866 modprobe i810_audio clocking=48000 867ERST 868 869DEF("device", HAS_ARG, QEMU_OPTION_device, 870 "-device driver[,prop[=value][,...]]\n" 871 " add device (based on driver)\n" 872 " prop=value,... sets driver properties\n" 873 " use '-device help' to print all possible drivers\n" 874 " use '-device driver,help' to print all possible properties\n", 875 QEMU_ARCH_ALL) 876SRST 877``-device driver[,prop[=value][,...]]`` 878 Add device driver. prop=value sets driver properties. Valid 879 properties depend on the driver. To get help on possible drivers and 880 properties, use ``-device help`` and ``-device driver,help``. 881 882 Some drivers are: 883 884``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 885 Add an IPMI BMC. This is a simulation of a hardware management 886 interface processor that normally sits on a system. It provides a 887 watchdog and the ability to reset and power control the system. You 888 need to connect this to an IPMI interface to make it useful 889 890 The IPMI slave address to use for the BMC. The default is 0x20. This 891 address is the BMC's address on the I2C network of management 892 controllers. If you don't know what this means, it is safe to ignore 893 it. 894 895 ``id=id`` 896 The BMC id for interfaces to use this device. 897 898 ``slave_addr=val`` 899 Define slave address to use for the BMC. The default is 0x20. 900 901 ``sdrfile=file`` 902 file containing raw Sensor Data Records (SDR) data. The default 903 is none. 904 905 ``fruareasize=val`` 906 size of a Field Replaceable Unit (FRU) area. The default is 907 1024. 908 909 ``frudatafile=file`` 910 file containing raw Field Replaceable Unit (FRU) inventory data. 911 The default is none. 912 913 ``guid=uuid`` 914 value for the GUID for the BMC, in standard UUID format. If this 915 is set, get "Get GUID" command to the BMC will return it. 916 Otherwise "Get GUID" will return an error. 917 918``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 919 Add a connection to an external IPMI BMC simulator. Instead of 920 locally emulating the BMC like the above item, instead connect to an 921 external entity that provides the IPMI services. 922 923 A connection is made to an external BMC simulator. If you do this, 924 it is strongly recommended that you use the "reconnect=" chardev 925 option to reconnect to the simulator if the connection is lost. Note 926 that if this is not used carefully, it can be a security issue, as 927 the interface has the ability to send resets, NMIs, and power off 928 the VM. It's best if QEMU makes a connection to an external 929 simulator running on a secure port on localhost, so neither the 930 simulator nor QEMU is exposed to any outside network. 931 932 See the "lanserv/README.vm" file in the OpenIPMI library for more 933 details on the external interface. 934 935``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 936 Add a KCS IPMI interafce on the ISA bus. This also adds a 937 corresponding ACPI and SMBIOS entries, if appropriate. 938 939 ``bmc=id`` 940 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 941 above. 942 943 ``ioport=val`` 944 Define the I/O address of the interface. The default is 0xca0 945 for KCS. 946 947 ``irq=val`` 948 Define the interrupt to use. The default is 5. To disable 949 interrupts, set this to 0. 950 951``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 952 Like the KCS interface, but defines a BT interface. The default port 953 is 0xe4 and the default interrupt is 5. 954 955``-device pci-ipmi-kcs,bmc=id`` 956 Add a KCS IPMI interafce on the PCI bus. 957 958 ``bmc=id`` 959 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 960 961``-device pci-ipmi-bt,bmc=id`` 962 Like the KCS interface, but defines a BT interface on the PCI bus. 963 964``-device intel-iommu[,option=...]`` 965 This is only supported by ``-machine q35``, which will enable Intel VT-d 966 emulation within the guest. It supports below options: 967 968 ``intremap=on|off`` (default: auto) 969 This enables interrupt remapping feature. It's required to enable 970 complete x2apic. Currently it only supports kvm kernel-irqchip modes 971 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 972 The default value is "auto", which will be decided by the mode of 973 kernel-irqchip. 974 975 ``caching-mode=on|off`` (default: off) 976 This enables caching mode for the VT-d emulated device. When 977 caching-mode is enabled, each guest DMA buffer mapping will generate an 978 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 979 a synchronous way. It is required for ``-device vfio-pci`` to work 980 with the VT-d device, because host assigned devices requires to setup 981 the DMA mapping on the host before guest DMA starts. 982 983 ``device-iotlb=on|off`` (default: off) 984 This enables device-iotlb capability for the emulated VT-d device. So 985 far virtio/vhost should be the only real user for this parameter, 986 paired with ats=on configured for the device. 987 988 ``aw-bits=39|48`` (default: 39) 989 This decides the address width of IOVA address space. The address 990 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 991 4-level IOMMU page tables. 992 993 Please also refer to the wiki page for general scenarios of VT-d 994 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 995 996ERST 997 998DEF("name", HAS_ARG, QEMU_OPTION_name, 999 "-name string1[,process=string2][,debug-threads=on|off]\n" 1000 " set the name of the guest\n" 1001 " string1 sets the window title and string2 the process name\n" 1002 " When debug-threads is enabled, individual threads are given a separate name\n" 1003 " NOTE: The thread names are for debugging and not a stable API.\n", 1004 QEMU_ARCH_ALL) 1005SRST 1006``-name name`` 1007 Sets the name of the guest. This name will be displayed in the SDL 1008 window caption. The name will also be used for the VNC server. Also 1009 optionally set the top visible process name in Linux. Naming of 1010 individual threads can also be enabled on Linux to aid debugging. 1011ERST 1012 1013DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1014 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1015 " specify machine UUID\n", QEMU_ARCH_ALL) 1016SRST 1017``-uuid uuid`` 1018 Set system UUID. 1019ERST 1020 1021DEFHEADING() 1022 1023DEFHEADING(Block device options:) 1024 1025DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1026 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1027DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1028SRST 1029``-fda file`` 1030 \ 1031``-fdb file`` 1032 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1033 the System Emulation Users Guide). 1034ERST 1035 1036DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1037 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1038DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1039DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1040 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1041DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1042SRST 1043``-hda file`` 1044 \ 1045``-hdb file`` 1046 \ 1047``-hdc file`` 1048 \ 1049``-hdd file`` 1050 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1051 chapter in the System Emulation Users Guide). 1052ERST 1053 1054DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1055 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1056 QEMU_ARCH_ALL) 1057SRST 1058``-cdrom file`` 1059 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1060 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1061 as filename. 1062ERST 1063 1064DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1065 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1066 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1067 " [,read-only=on|off][,auto-read-only=on|off]\n" 1068 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1069 " [,driver specific parameters...]\n" 1070 " configure a block backend\n", QEMU_ARCH_ALL) 1071SRST 1072``-blockdev option[,option[,option[,...]]]`` 1073 Define a new block driver node. Some of the options apply to all 1074 block drivers, other options are only accepted for a specific block 1075 driver. See below for a list of generic options and options for the 1076 most common block drivers. 1077 1078 Options that expect a reference to another node (e.g. ``file``) can 1079 be given in two ways. Either you specify the node name of an already 1080 existing node (file=node-name), or you define a new node inline, 1081 adding options for the referenced node after a dot 1082 (file.filename=path,file.aio=native). 1083 1084 A block driver node created with ``-blockdev`` can be used for a 1085 guest device by specifying its node name for the ``drive`` property 1086 in a ``-device`` argument that defines a block device. 1087 1088 ``Valid options for any block driver node:`` 1089 ``driver`` 1090 Specifies the block driver to use for the given node. 1091 1092 ``node-name`` 1093 This defines the name of the block driver node by which it 1094 will be referenced later. The name must be unique, i.e. it 1095 must not match the name of a different block driver node, or 1096 (if you use ``-drive`` as well) the ID of a drive. 1097 1098 If no node name is specified, it is automatically generated. 1099 The generated node name is not intended to be predictable 1100 and changes between QEMU invocations. For the top level, an 1101 explicit node name must be specified. 1102 1103 ``read-only`` 1104 Open the node read-only. Guest write attempts will fail. 1105 1106 Note that some block drivers support only read-only access, 1107 either generally or in certain configurations. In this case, 1108 the default value ``read-only=off`` does not work and the 1109 option must be specified explicitly. 1110 1111 ``auto-read-only`` 1112 If ``auto-read-only=on`` is set, QEMU may fall back to 1113 read-only usage even when ``read-only=off`` is requested, or 1114 even switch between modes as needed, e.g. depending on 1115 whether the image file is writable or whether a writing user 1116 is attached to the node. 1117 1118 ``force-share`` 1119 Override the image locking system of QEMU by forcing the 1120 node to utilize weaker shared access for permissions where 1121 it would normally request exclusive access. When there is 1122 the potential for multiple instances to have the same file 1123 open (whether this invocation of QEMU is the first or the 1124 second instance), both instances must permit shared access 1125 for the second instance to succeed at opening the file. 1126 1127 Enabling ``force-share=on`` requires ``read-only=on``. 1128 1129 ``cache.direct`` 1130 The host page cache can be avoided with ``cache.direct=on``. 1131 This will attempt to do disk IO directly to the guest's 1132 memory. QEMU may still perform an internal copy of the data. 1133 1134 ``cache.no-flush`` 1135 In case you don't care about data integrity over host 1136 failures, you can use ``cache.no-flush=on``. This option 1137 tells QEMU that it never needs to write any data to the disk 1138 but can instead keep things in cache. If anything goes 1139 wrong, like your host losing power, the disk storage getting 1140 disconnected accidentally, etc. your image will most 1141 probably be rendered unusable. 1142 1143 ``discard=discard`` 1144 discard is one of "ignore" (or "off") or "unmap" (or "on") 1145 and controls whether ``discard`` (also known as ``trim`` or 1146 ``unmap``) requests are ignored or passed to the filesystem. 1147 Some machine types may not support discard requests. 1148 1149 ``detect-zeroes=detect-zeroes`` 1150 detect-zeroes is "off", "on" or "unmap" and enables the 1151 automatic conversion of plain zero writes by the OS to 1152 driver specific optimized zero write commands. You may even 1153 choose "unmap" if discard is set to "unmap" to allow a zero 1154 write to be converted to an ``unmap`` operation. 1155 1156 ``Driver-specific options for file`` 1157 This is the protocol-level block driver for accessing regular 1158 files. 1159 1160 ``filename`` 1161 The path to the image file in the local filesystem 1162 1163 ``aio`` 1164 Specifies the AIO backend (threads/native/io_uring, 1165 default: threads) 1166 1167 ``locking`` 1168 Specifies whether the image file is protected with Linux OFD 1169 / POSIX locks. The default is to use the Linux Open File 1170 Descriptor API if available, otherwise no lock is applied. 1171 (auto/on/off, default: auto) 1172 1173 Example: 1174 1175 :: 1176 1177 -blockdev driver=file,node-name=disk,filename=disk.img 1178 1179 ``Driver-specific options for raw`` 1180 This is the image format block driver for raw images. It is 1181 usually stacked on top of a protocol level block driver such as 1182 ``file``. 1183 1184 ``file`` 1185 Reference to or definition of the data source block driver 1186 node (e.g. a ``file`` driver node) 1187 1188 Example 1: 1189 1190 :: 1191 1192 -blockdev driver=file,node-name=disk_file,filename=disk.img 1193 -blockdev driver=raw,node-name=disk,file=disk_file 1194 1195 Example 2: 1196 1197 :: 1198 1199 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1200 1201 ``Driver-specific options for qcow2`` 1202 This is the image format block driver for qcow2 images. It is 1203 usually stacked on top of a protocol level block driver such as 1204 ``file``. 1205 1206 ``file`` 1207 Reference to or definition of the data source block driver 1208 node (e.g. a ``file`` driver node) 1209 1210 ``backing`` 1211 Reference to or definition of the backing file block device 1212 (default is taken from the image file). It is allowed to 1213 pass ``null`` here in order to disable the default backing 1214 file. 1215 1216 ``lazy-refcounts`` 1217 Whether to enable the lazy refcounts feature (on/off; 1218 default is taken from the image file) 1219 1220 ``cache-size`` 1221 The maximum total size of the L2 table and refcount block 1222 caches in bytes (default: the sum of l2-cache-size and 1223 refcount-cache-size) 1224 1225 ``l2-cache-size`` 1226 The maximum size of the L2 table cache in bytes (default: if 1227 cache-size is not specified - 32M on Linux platforms, and 8M 1228 on non-Linux platforms; otherwise, as large as possible 1229 within the cache-size, while permitting the requested or the 1230 minimal refcount cache size) 1231 1232 ``refcount-cache-size`` 1233 The maximum size of the refcount block cache in bytes 1234 (default: 4 times the cluster size; or if cache-size is 1235 specified, the part of it which is not used for the L2 1236 cache) 1237 1238 ``cache-clean-interval`` 1239 Clean unused entries in the L2 and refcount caches. The 1240 interval is in seconds. The default value is 600 on 1241 supporting platforms, and 0 on other platforms. Setting it 1242 to 0 disables this feature. 1243 1244 ``pass-discard-request`` 1245 Whether discard requests to the qcow2 device should be 1246 forwarded to the data source (on/off; default: on if 1247 discard=unmap is specified, off otherwise) 1248 1249 ``pass-discard-snapshot`` 1250 Whether discard requests for the data source should be 1251 issued when a snapshot operation (e.g. deleting a snapshot) 1252 frees clusters in the qcow2 file (on/off; default: on) 1253 1254 ``pass-discard-other`` 1255 Whether discard requests for the data source should be 1256 issued on other occasions where a cluster gets freed 1257 (on/off; default: off) 1258 1259 ``overlap-check`` 1260 Which overlap checks to perform for writes to the image 1261 (none/constant/cached/all; default: cached). For details or 1262 finer granularity control refer to the QAPI documentation of 1263 ``blockdev-add``. 1264 1265 Example 1: 1266 1267 :: 1268 1269 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1270 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1271 1272 Example 2: 1273 1274 :: 1275 1276 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1277 1278 ``Driver-specific options for other drivers`` 1279 Please refer to the QAPI documentation of the ``blockdev-add`` 1280 QMP command. 1281ERST 1282 1283DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1284 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1285 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1286 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1287 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1288 " [,aio=threads|native|io_uring]\n" 1289 " [,readonly=on|off][,copy-on-read=on|off]\n" 1290 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1291 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1292 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1293 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1294 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1295 " [[,iops_size=is]]\n" 1296 " [[,group=g]]\n" 1297 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1298SRST 1299``-drive option[,option[,option[,...]]]`` 1300 Define a new drive. This includes creating a block driver node (the 1301 backend) as well as a guest device, and is mostly a shortcut for 1302 defining the corresponding ``-blockdev`` and ``-device`` options. 1303 1304 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1305 In addition, it knows the following options: 1306 1307 ``file=file`` 1308 This option defines which disk image (see the :ref:`disk images` 1309 chapter in the System Emulation Users Guide) to use with this drive. 1310 If the filename contains comma, you must double it (for instance, 1311 "file=my,,file" to use file "my,file"). 1312 1313 Special files such as iSCSI devices can be specified using 1314 protocol specific URLs. See the section for "Device URL Syntax" 1315 for more information. 1316 1317 ``if=interface`` 1318 This option defines on which type on interface the drive is 1319 connected. Available types are: ide, scsi, sd, mtd, floppy, 1320 pflash, virtio, none. 1321 1322 ``bus=bus,unit=unit`` 1323 These options define where is connected the drive by defining 1324 the bus number and the unit id. 1325 1326 ``index=index`` 1327 This option defines where is connected the drive by using an 1328 index in the list of available connectors of a given interface 1329 type. 1330 1331 ``media=media`` 1332 This option defines the type of the media: disk or cdrom. 1333 1334 ``snapshot=snapshot`` 1335 snapshot is "on" or "off" and controls snapshot mode for the 1336 given drive (see ``-snapshot``). 1337 1338 ``cache=cache`` 1339 cache is "none", "writeback", "unsafe", "directsync" or 1340 "writethrough" and controls how the host cache is used to access 1341 block data. This is a shortcut that sets the ``cache.direct`` 1342 and ``cache.no-flush`` options (as in ``-blockdev``), and 1343 additionally ``cache.writeback``, which provides a default for 1344 the ``write-cache`` option of block guest devices (as in 1345 ``-device``). The modes correspond to the following settings: 1346 1347 ============= =============== ============ ============== 1348 \ cache.writeback cache.direct cache.no-flush 1349 ============= =============== ============ ============== 1350 writeback on off off 1351 none on on off 1352 writethrough off off off 1353 directsync off on off 1354 unsafe on off on 1355 ============= =============== ============ ============== 1356 1357 The default mode is ``cache=writeback``. 1358 1359 ``aio=aio`` 1360 aio is "threads", "native", or "io_uring" and selects between pthread 1361 based disk I/O, native Linux AIO, or Linux io_uring API. 1362 1363 ``format=format`` 1364 Specify which disk format will be used rather than detecting the 1365 format. Can be used to specify format=raw to avoid interpreting 1366 an untrusted format header. 1367 1368 ``werror=action,rerror=action`` 1369 Specify which action to take on write and read errors. Valid 1370 actions are: "ignore" (ignore the error and try to continue), 1371 "stop" (pause QEMU), "report" (report the error to the guest), 1372 "enospc" (pause QEMU only if the host disk is full; report the 1373 error to the guest otherwise). The default setting is 1374 ``werror=enospc`` and ``rerror=report``. 1375 1376 ``copy-on-read=copy-on-read`` 1377 copy-on-read is "on" or "off" and enables whether to copy read 1378 backing file sectors into the image file. 1379 1380 ``bps=b,bps_rd=r,bps_wr=w`` 1381 Specify bandwidth throttling limits in bytes per second, either 1382 for all request types or for reads or writes only. Small values 1383 can lead to timeouts or hangs inside the guest. A safe minimum 1384 for disks is 2 MB/s. 1385 1386 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1387 Specify bursts in bytes per second, either for all request types 1388 or for reads or writes only. Bursts allow the guest I/O to spike 1389 above the limit temporarily. 1390 1391 ``iops=i,iops_rd=r,iops_wr=w`` 1392 Specify request rate limits in requests per second, either for 1393 all request types or for reads or writes only. 1394 1395 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1396 Specify bursts in requests per second, either for all request 1397 types or for reads or writes only. Bursts allow the guest I/O to 1398 spike above the limit temporarily. 1399 1400 ``iops_size=is`` 1401 Let every is bytes of a request count as a new request for iops 1402 throttling purposes. Use this option to prevent guests from 1403 circumventing iops limits by sending fewer but larger requests. 1404 1405 ``group=g`` 1406 Join a throttling quota group with given name g. All drives that 1407 are members of the same group are accounted for together. Use 1408 this option to prevent guests from circumventing throttling 1409 limits by using many small disks instead of a single larger 1410 disk. 1411 1412 By default, the ``cache.writeback=on`` mode is used. It will report 1413 data writes as completed as soon as the data is present in the host 1414 page cache. This is safe as long as your guest OS makes sure to 1415 correctly flush disk caches where needed. If your guest OS does not 1416 handle volatile disk write caches correctly and your host crashes or 1417 loses power, then the guest may experience data corruption. 1418 1419 For such guests, you should consider using ``cache.writeback=off``. 1420 This means that the host page cache will be used to read and write 1421 data, but write notification will be sent to the guest only after 1422 QEMU has made sure to flush each write to the disk. Be aware that 1423 this has a major impact on performance. 1424 1425 When using the ``-snapshot`` option, unsafe caching is always used. 1426 1427 Copy-on-read avoids accessing the same backing file sectors 1428 repeatedly and is useful when the backing file is over a slow 1429 network. By default copy-on-read is off. 1430 1431 Instead of ``-cdrom`` you can use: 1432 1433 .. parsed-literal:: 1434 1435 |qemu_system| -drive file=file,index=2,media=cdrom 1436 1437 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1438 1439 .. parsed-literal:: 1440 1441 |qemu_system| -drive file=file,index=0,media=disk 1442 |qemu_system| -drive file=file,index=1,media=disk 1443 |qemu_system| -drive file=file,index=2,media=disk 1444 |qemu_system| -drive file=file,index=3,media=disk 1445 1446 You can open an image using pre-opened file descriptors from an fd 1447 set: 1448 1449 .. parsed-literal:: 1450 1451 |qemu_system| \\ 1452 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1453 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1454 -drive file=/dev/fdset/2,index=0,media=disk 1455 1456 You can connect a CDROM to the slave of ide0: 1457 1458 .. parsed-literal:: 1459 1460 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1461 1462 If you don't specify the "file=" argument, you define an empty 1463 drive: 1464 1465 .. parsed-literal:: 1466 1467 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1468 1469 Instead of ``-fda``, ``-fdb``, you can use: 1470 1471 .. parsed-literal:: 1472 1473 |qemu_system_x86| -drive file=file,index=0,if=floppy 1474 |qemu_system_x86| -drive file=file,index=1,if=floppy 1475 1476 By default, interface is "ide" and index is automatically 1477 incremented: 1478 1479 .. parsed-literal:: 1480 1481 |qemu_system_x86| -drive file=a -drive file=b" 1482 1483 is interpreted like: 1484 1485 .. parsed-literal:: 1486 1487 |qemu_system_x86| -hda a -hdb b 1488ERST 1489 1490DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1491 "-mtdblock file use 'file' as on-board Flash memory image\n", 1492 QEMU_ARCH_ALL) 1493SRST 1494``-mtdblock file`` 1495 Use file as on-board Flash memory image. 1496ERST 1497 1498DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1499 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1500SRST 1501``-sd file`` 1502 Use file as SecureDigital card image. 1503ERST 1504 1505DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1506 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1507SRST 1508``-pflash file`` 1509 Use file as a parallel flash image. 1510ERST 1511 1512DEF("snapshot", 0, QEMU_OPTION_snapshot, 1513 "-snapshot write to temporary files instead of disk image files\n", 1514 QEMU_ARCH_ALL) 1515SRST 1516``-snapshot`` 1517 Write to temporary files instead of disk image files. In this case, 1518 the raw disk image you use is not written back. You can however 1519 force the write back by pressing C-a s (see the :ref:`disk images` 1520 chapter in the System Emulation Users Guide). 1521ERST 1522 1523DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1524 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1525 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1526 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1527 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1528 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1529 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1530 " [[,throttling.iops-size=is]]\n" 1531 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1532 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1533 "-fsdev synth,id=id\n", 1534 QEMU_ARCH_ALL) 1535 1536SRST 1537``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1538 \ 1539``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1540 \ 1541``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1542 \ 1543``-fsdev synth,id=id[,readonly=on]`` 1544 Define a new file system device. Valid options are: 1545 1546 ``local`` 1547 Accesses to the filesystem are done by QEMU. 1548 1549 ``proxy`` 1550 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1551 1552 ``synth`` 1553 Synthetic filesystem, only used by QTests. 1554 1555 ``id=id`` 1556 Specifies identifier for this device. 1557 1558 ``path=path`` 1559 Specifies the export path for the file system device. Files 1560 under this path will be available to the 9p client on the guest. 1561 1562 ``security_model=security_model`` 1563 Specifies the security model to be used for this export path. 1564 Supported security models are "passthrough", "mapped-xattr", 1565 "mapped-file" and "none". In "passthrough" security model, files 1566 are stored using the same credentials as they are created on the 1567 guest. This requires QEMU to run as root. In "mapped-xattr" 1568 security model, some of the file attributes like uid, gid, mode 1569 bits and link target are stored as file attributes. For 1570 "mapped-file" these attributes are stored in the hidden 1571 .virtfs\_metadata directory. Directories exported by this 1572 security model cannot interact with other unix tools. "none" 1573 security model is same as passthrough except the sever won't 1574 report failures if it fails to set file attributes like 1575 ownership. Security model is mandatory only for local fsdriver. 1576 Other fsdrivers (like proxy) don't take security model as a 1577 parameter. 1578 1579 ``writeout=writeout`` 1580 This is an optional argument. The only supported value is 1581 "immediate". This means that host page cache will be used to 1582 read and write data but write notification will be sent to the 1583 guest only when the data has been reported as written by the 1584 storage subsystem. 1585 1586 ``readonly=on`` 1587 Enables exporting 9p share as a readonly mount for guests. By 1588 default read-write access is given. 1589 1590 ``socket=socket`` 1591 Enables proxy filesystem driver to use passed socket file for 1592 communicating with virtfs-proxy-helper(1). 1593 1594 ``sock_fd=sock_fd`` 1595 Enables proxy filesystem driver to use passed socket descriptor 1596 for communicating with virtfs-proxy-helper(1). Usually a helper 1597 like libvirt will create socketpair and pass one of the fds as 1598 sock\_fd. 1599 1600 ``fmode=fmode`` 1601 Specifies the default mode for newly created files on the host. 1602 Works only with security models "mapped-xattr" and 1603 "mapped-file". 1604 1605 ``dmode=dmode`` 1606 Specifies the default mode for newly created directories on the 1607 host. Works only with security models "mapped-xattr" and 1608 "mapped-file". 1609 1610 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1611 Specify bandwidth throttling limits in bytes per second, either 1612 for all request types or for reads or writes only. 1613 1614 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1615 Specify bursts in bytes per second, either for all request types 1616 or for reads or writes only. Bursts allow the guest I/O to spike 1617 above the limit temporarily. 1618 1619 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1620 Specify request rate limits in requests per second, either for 1621 all request types or for reads or writes only. 1622 1623 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1624 Specify bursts in requests per second, either for all request 1625 types or for reads or writes only. Bursts allow the guest I/O to 1626 spike above the limit temporarily. 1627 1628 ``throttling.iops-size=is`` 1629 Let every is bytes of a request count as a new request for iops 1630 throttling purposes. 1631 1632 -fsdev option is used along with -device driver "virtio-9p-...". 1633 1634``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1635 Options for virtio-9p-... driver are: 1636 1637 ``type`` 1638 Specifies the variant to be used. Supported values are "pci", 1639 "ccw" or "device", depending on the machine type. 1640 1641 ``fsdev=id`` 1642 Specifies the id value specified along with -fsdev option. 1643 1644 ``mount_tag=mount_tag`` 1645 Specifies the tag name to be used by the guest to mount this 1646 export point. 1647ERST 1648 1649DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1650 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1651 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1652 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1653 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1654 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1655 QEMU_ARCH_ALL) 1656 1657SRST 1658``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1659 \ 1660``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1661 \ 1662``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1663 \ 1664``-virtfs synth,mount_tag=mount_tag`` 1665 Define a new virtual filesystem device and expose it to the guest using 1666 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1667 directory on host is made directly accessible by guest as a pass-through 1668 file system by using the 9P network protocol for communication between 1669 host and guests, if desired even accessible, shared by several guests 1670 simultaniously. 1671 1672 Note that ``-virtfs`` is actually just a convenience shortcut for its 1673 generalized form ``-fsdev -device virtio-9p-pci``. 1674 1675 The general form of pass-through file system options are: 1676 1677 ``local`` 1678 Accesses to the filesystem are done by QEMU. 1679 1680 ``proxy`` 1681 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1682 1683 ``synth`` 1684 Synthetic filesystem, only used by QTests. 1685 1686 ``id=id`` 1687 Specifies identifier for the filesystem device 1688 1689 ``path=path`` 1690 Specifies the export path for the file system device. Files 1691 under this path will be available to the 9p client on the guest. 1692 1693 ``security_model=security_model`` 1694 Specifies the security model to be used for this export path. 1695 Supported security models are "passthrough", "mapped-xattr", 1696 "mapped-file" and "none". In "passthrough" security model, files 1697 are stored using the same credentials as they are created on the 1698 guest. This requires QEMU to run as root. In "mapped-xattr" 1699 security model, some of the file attributes like uid, gid, mode 1700 bits and link target are stored as file attributes. For 1701 "mapped-file" these attributes are stored in the hidden 1702 .virtfs\_metadata directory. Directories exported by this 1703 security model cannot interact with other unix tools. "none" 1704 security model is same as passthrough except the sever won't 1705 report failures if it fails to set file attributes like 1706 ownership. Security model is mandatory only for local fsdriver. 1707 Other fsdrivers (like proxy) don't take security model as a 1708 parameter. 1709 1710 ``writeout=writeout`` 1711 This is an optional argument. The only supported value is 1712 "immediate". This means that host page cache will be used to 1713 read and write data but write notification will be sent to the 1714 guest only when the data has been reported as written by the 1715 storage subsystem. 1716 1717 ``readonly=on`` 1718 Enables exporting 9p share as a readonly mount for guests. By 1719 default read-write access is given. 1720 1721 ``socket=socket`` 1722 Enables proxy filesystem driver to use passed socket file for 1723 communicating with virtfs-proxy-helper(1). Usually a helper like 1724 libvirt will create socketpair and pass one of the fds as 1725 sock\_fd. 1726 1727 ``sock_fd`` 1728 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1729 socket descriptor for interfacing with virtfs-proxy-helper(1). 1730 1731 ``fmode=fmode`` 1732 Specifies the default mode for newly created files on the host. 1733 Works only with security models "mapped-xattr" and 1734 "mapped-file". 1735 1736 ``dmode=dmode`` 1737 Specifies the default mode for newly created directories on the 1738 host. Works only with security models "mapped-xattr" and 1739 "mapped-file". 1740 1741 ``mount_tag=mount_tag`` 1742 Specifies the tag name to be used by the guest to mount this 1743 export point. 1744 1745 ``multidevs=multidevs`` 1746 Specifies how to deal with multiple devices being shared with a 1747 9p export. Supported behaviours are either "remap", "forbid" or 1748 "warn". The latter is the default behaviour on which virtfs 9p 1749 expects only one device to be shared with the same export, and 1750 if more than one device is shared and accessed via the same 9p 1751 export then only a warning message is logged (once) by qemu on 1752 host side. In order to avoid file ID collisions on guest you 1753 should either create a separate virtfs export for each device to 1754 be shared with guests (recommended way) or you might use "remap" 1755 instead which allows you to share multiple devices with only one 1756 export instead, which is achieved by remapping the original 1757 inode numbers from host to guest in a way that would prevent 1758 such collisions. Remapping inodes in such use cases is required 1759 because the original device IDs from host are never passed and 1760 exposed on guest. Instead all files of an export shared with 1761 virtfs always share the same device id on guest. So two files 1762 with identical inode numbers but from actually different devices 1763 on host would otherwise cause a file ID collision and hence 1764 potential misbehaviours on guest. "forbid" on the other hand 1765 assumes like "warn" that only one device is shared by the same 1766 export, however it will not only log a warning message but also 1767 deny access to additional devices on guest. Note though that 1768 "forbid" does currently not block all possible file access 1769 operations (e.g. readdir() would still return entries from other 1770 devices). 1771ERST 1772 1773DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1774 "-iscsi [user=user][,password=password]\n" 1775 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1776 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1777 " [,timeout=timeout]\n" 1778 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1779 1780SRST 1781``-iscsi`` 1782 Configure iSCSI session parameters. 1783ERST 1784 1785DEFHEADING() 1786 1787DEFHEADING(USB convenience options:) 1788 1789DEF("usb", 0, QEMU_OPTION_usb, 1790 "-usb enable on-board USB host controller (if not enabled by default)\n", 1791 QEMU_ARCH_ALL) 1792SRST 1793``-usb`` 1794 Enable USB emulation on machine types with an on-board USB host 1795 controller (if not enabled by default). Note that on-board USB host 1796 controllers may not support USB 3.0. In this case 1797 ``-device qemu-xhci`` can be used instead on machines with PCI. 1798ERST 1799 1800DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1801 "-usbdevice name add the host or guest USB device 'name'\n", 1802 QEMU_ARCH_ALL) 1803SRST 1804``-usbdevice devname`` 1805 Add the USB device devname, and enable an on-board USB controller 1806 if possible and necessary (just like it can be done via 1807 ``-machine usb=on``). Note that this option is mainly intended for 1808 the user's convenience only. More fine-grained control can be 1809 achieved by selecting a USB host controller (if necessary) and the 1810 desired USB device via the ``-device`` option instead. For example, 1811 instead of using ``-usbdevice mouse`` it is possible to use 1812 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1813 to a USB 3.0 controller instead (at least on machines that support 1814 PCI and do not have an USB controller enabled by default yet). 1815 For more details, see the chapter about 1816 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1817 Possible devices for devname are: 1818 1819 ``braille`` 1820 Braille device. This will use BrlAPI to display the braille 1821 output on a real or fake device (i.e. it also creates a 1822 corresponding ``braille`` chardev automatically beside the 1823 ``usb-braille`` USB device). 1824 1825 ``keyboard`` 1826 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1827 1828 ``mouse`` 1829 Virtual Mouse. This will override the PS/2 mouse emulation when 1830 activated. 1831 1832 ``tablet`` 1833 Pointer device that uses absolute coordinates (like a 1834 touchscreen). This means QEMU is able to report the mouse 1835 position without having to grab the mouse. Also overrides the 1836 PS/2 mouse emulation when activated. 1837 1838 ``wacom-tablet`` 1839 Wacom PenPartner USB tablet. 1840 1841 1842ERST 1843 1844DEFHEADING() 1845 1846DEFHEADING(Display options:) 1847 1848DEF("display", HAS_ARG, QEMU_OPTION_display, 1849#if defined(CONFIG_SPICE) 1850 "-display spice-app[,gl=on|off]\n" 1851#endif 1852#if defined(CONFIG_SDL) 1853 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1854 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n" 1855#endif 1856#if defined(CONFIG_GTK) 1857 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1858 " [,show-cursor=on|off][,window-close=on|off]\n" 1859#endif 1860#if defined(CONFIG_VNC) 1861 "-display vnc=<display>[,<optargs>]\n" 1862#endif 1863#if defined(CONFIG_CURSES) 1864 "-display curses[,charset=<encoding>]\n" 1865#endif 1866#if defined(CONFIG_OPENGL) 1867 "-display egl-headless[,rendernode=<file>]\n" 1868#endif 1869#if defined(CONFIG_DBUS_DISPLAY) 1870 "-display dbus[,addr=<dbusaddr>]\n" 1871 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1872#endif 1873 "-display none\n" 1874 " select display backend type\n" 1875 " The default display is equivalent to\n " 1876#if defined(CONFIG_GTK) 1877 "\"-display gtk\"\n" 1878#elif defined(CONFIG_SDL) 1879 "\"-display sdl\"\n" 1880#elif defined(CONFIG_COCOA) 1881 "\"-display cocoa\"\n" 1882#elif defined(CONFIG_VNC) 1883 "\"-vnc localhost:0,to=99,id=default\"\n" 1884#else 1885 "\"-display none\"\n" 1886#endif 1887 , QEMU_ARCH_ALL) 1888SRST 1889``-display type`` 1890 Select type of display to use. This option is a replacement for the 1891 old style -sdl/-curses/... options. Use ``-display help`` to list 1892 the available display types. Valid values for type are 1893 1894 ``spice-app[,gl=on|off]`` 1895 Start QEMU as a Spice server and launch the default Spice client 1896 application. The Spice server will redirect the serial consoles 1897 and QEMU monitors. (Since 4.0) 1898 1899 ``dbus`` 1900 Export the display over D-Bus interfaces. (Since 7.0) 1901 1902 The connection is registered with the "org.qemu" name (and queued when 1903 already owned). 1904 1905 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 1906 1907 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 1908 1909 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 1910 will share framebuffers with DMABUF file descriptors). 1911 1912 ``sdl`` 1913 Display video output via SDL (usually in a separate graphics 1914 window; see the SDL documentation for other possibilities). 1915 Valid parameters are: 1916 1917 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 1918 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 1919 either ``lshift-lctrl-lalt`` or ``rctrl``. 1920 1921 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing. 1922 This parameter is deprecated - use ``grab-mod`` instead. 1923 1924 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing. 1925 This parameter is deprecated - use ``grab-mod`` instead. 1926 1927 ``gl=on|off|core|es`` : Use OpenGL for displaying 1928 1929 ``show-cursor=on|off`` : Force showing the mouse cursor 1930 1931 ``window-close=on|off`` : Allow to quit qemu with window close button 1932 1933 ``gtk`` 1934 Display video output in a GTK window. This interface provides 1935 drop-down menus and other UI elements to configure and control 1936 the VM during runtime. Valid parameters are: 1937 1938 ``full-screen=on|off`` : Start in fullscreen mode 1939 1940 ``gl=on|off`` : Use OpenGL for displaying 1941 1942 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 1943 1944 ``show-cursor=on|off`` : Force showing the mouse cursor 1945 1946 ``window-close=on|off`` : Allow to quit qemu with window close button 1947 1948 ``curses[,charset=<encoding>]`` 1949 Display video output via curses. For graphics device models 1950 which support a text mode, QEMU can display this output using a 1951 curses/ncurses interface. Nothing is displayed when the graphics 1952 device is in graphical mode or if the graphics device does not 1953 support a text mode. Generally only the VGA device models 1954 support text mode. The font charset used by the guest can be 1955 specified with the ``charset`` option, for example 1956 ``charset=CP850`` for IBM CP850 encoding. The default is 1957 ``CP437``. 1958 1959 ``egl-headless[,rendernode=<file>]`` 1960 Offload all OpenGL operations to a local DRI device. For any 1961 graphical display, this display needs to be paired with either 1962 VNC or SPICE displays. 1963 1964 ``vnc=<display>`` 1965 Start a VNC server on display <display> 1966 1967 ``none`` 1968 Do not display video output. The guest will still see an 1969 emulated graphics card, but its output will not be displayed to 1970 the QEMU user. This option differs from the -nographic option in 1971 that it only affects what is done with video output; -nographic 1972 also changes the destination of the serial and parallel port 1973 data. 1974ERST 1975 1976DEF("nographic", 0, QEMU_OPTION_nographic, 1977 "-nographic disable graphical output and redirect serial I/Os to console\n", 1978 QEMU_ARCH_ALL) 1979SRST 1980``-nographic`` 1981 Normally, if QEMU is compiled with graphical window support, it 1982 displays output such as guest graphics, guest console, and the QEMU 1983 monitor in a window. With this option, you can totally disable 1984 graphical output so that QEMU is a simple command line application. 1985 The emulated serial port is redirected on the console and muxed with 1986 the monitor (unless redirected elsewhere explicitly). Therefore, you 1987 can still use QEMU to debug a Linux kernel with a serial console. 1988 Use C-a h for help on switching between the console and monitor. 1989ERST 1990 1991DEF("curses", 0, QEMU_OPTION_curses, 1992 "-curses shorthand for -display curses\n", 1993 QEMU_ARCH_ALL) 1994SRST 1995``-curses`` 1996 Normally, if QEMU is compiled with graphical window support, it 1997 displays output such as guest graphics, guest console, and the QEMU 1998 monitor in a window. With this option, QEMU can display the VGA 1999 output when in text mode using a curses/ncurses interface. Nothing 2000 is displayed in graphical mode. 2001ERST 2002 2003DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 2004 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 2005 QEMU_ARCH_ALL) 2006SRST 2007``-alt-grab`` 2008 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 2009 this also affects the special keys (for fullscreen, monitor-mode 2010 switching, etc). This option is deprecated - please use 2011 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead. 2012ERST 2013 2014DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 2015 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 2016 QEMU_ARCH_ALL) 2017SRST 2018``-ctrl-grab`` 2019 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 2020 also affects the special keys (for fullscreen, monitor-mode 2021 switching, etc). This option is deprecated - please use 2022 ``-display sdl,grab-mod=rctrl`` instead. 2023ERST 2024 2025DEF("no-quit", 0, QEMU_OPTION_no_quit, 2026 "-no-quit disable SDL/GTK window close capability (deprecated)\n", QEMU_ARCH_ALL) 2027SRST 2028``-no-quit`` 2029 Disable window close capability (SDL and GTK only). This option is 2030 deprecated, please use ``-display ...,window-close=off`` instead. 2031ERST 2032 2033DEF("sdl", 0, QEMU_OPTION_sdl, 2034 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 2035SRST 2036``-sdl`` 2037 Enable SDL. 2038ERST 2039 2040DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2041 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2042 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2043 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2044 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2045 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2046 " [,tls-ciphers=<list>]\n" 2047 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2048 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2049 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2050 " [,password=<string>][,password-secret=<secret-id>]\n" 2051 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2052 " [,jpeg-wan-compression=[auto|never|always]]\n" 2053 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2054 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2055 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2056 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2057 " [,gl=[on|off]][,rendernode=<file>]\n" 2058 " enable spice\n" 2059 " at least one of {port, tls-port} is mandatory\n", 2060 QEMU_ARCH_ALL) 2061SRST 2062``-spice option[,option[,...]]`` 2063 Enable the spice remote desktop protocol. Valid options are 2064 2065 ``port=<nr>`` 2066 Set the TCP port spice is listening on for plaintext channels. 2067 2068 ``addr=<addr>`` 2069 Set the IP address spice is listening on. Default is any 2070 address. 2071 2072 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2073 Force using the specified IP version. 2074 2075 ``password=<string>`` 2076 Set the password you need to authenticate. 2077 2078 This option is deprecated and insecure because it leaves the 2079 password visible in the process listing. Use ``password-secret`` 2080 instead. 2081 2082 ``password-secret=<secret-id>`` 2083 Set the ID of the ``secret`` object containing the password 2084 you need to authenticate. 2085 2086 ``sasl=on|off`` 2087 Require that the client use SASL to authenticate with the spice. 2088 The exact choice of authentication method used is controlled 2089 from the system / user's SASL configuration file for the 'qemu' 2090 service. This is typically found in /etc/sasl2/qemu.conf. If 2091 running QEMU as an unprivileged user, an environment variable 2092 SASL\_CONF\_PATH can be used to make it search alternate 2093 locations for the service config. While some SASL auth methods 2094 can also provide data encryption (eg GSSAPI), it is recommended 2095 that SASL always be combined with the 'tls' and 'x509' settings 2096 to enable use of SSL and server certificates. This ensures a 2097 data encryption preventing compromise of authentication 2098 credentials. 2099 2100 ``disable-ticketing=on|off`` 2101 Allow client connects without authentication. 2102 2103 ``disable-copy-paste=on|off`` 2104 Disable copy paste between the client and the guest. 2105 2106 ``disable-agent-file-xfer=on|off`` 2107 Disable spice-vdagent based file-xfer between the client and the 2108 guest. 2109 2110 ``tls-port=<nr>`` 2111 Set the TCP port spice is listening on for encrypted channels. 2112 2113 ``x509-dir=<dir>`` 2114 Set the x509 file directory. Expects same filenames as -vnc 2115 $display,x509=$dir 2116 2117 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2118 The x509 file names can also be configured individually. 2119 2120 ``tls-ciphers=<list>`` 2121 Specify which ciphers to use. 2122 2123 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2124 Force specific channel to be used with or without TLS 2125 encryption. The options can be specified multiple times to 2126 configure multiple channels. The special name "default" can be 2127 used to set the default mode. For channels which are not 2128 explicitly forced into one mode the spice client is allowed to 2129 pick tls/plaintext as he pleases. 2130 2131 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2132 Configure image compression (lossless). Default is auto\_glz. 2133 2134 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2135 Configure wan image compression (lossy for slow links). Default 2136 is auto. 2137 2138 ``streaming-video=[off|all|filter]`` 2139 Configure video stream detection. Default is off. 2140 2141 ``agent-mouse=[on|off]`` 2142 Enable/disable passing mouse events via vdagent. Default is on. 2143 2144 ``playback-compression=[on|off]`` 2145 Enable/disable audio stream compression (using celt 0.5.1). 2146 Default is on. 2147 2148 ``seamless-migration=[on|off]`` 2149 Enable/disable spice seamless migration. Default is off. 2150 2151 ``gl=[on|off]`` 2152 Enable/disable OpenGL context. Default is off. 2153 2154 ``rendernode=<file>`` 2155 DRM render node for OpenGL rendering. If not specified, it will 2156 pick the first available. (Since 2.9) 2157ERST 2158 2159DEF("portrait", 0, QEMU_OPTION_portrait, 2160 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2161 QEMU_ARCH_ALL) 2162SRST 2163``-portrait`` 2164 Rotate graphical output 90 deg left (only PXA LCD). 2165ERST 2166 2167DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2168 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2169 QEMU_ARCH_ALL) 2170SRST 2171``-rotate deg`` 2172 Rotate graphical output some deg left (only PXA LCD). 2173ERST 2174 2175DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2176 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2177 " select video card type\n", QEMU_ARCH_ALL) 2178SRST 2179``-vga type`` 2180 Select type of VGA card to emulate. Valid values for type are 2181 2182 ``cirrus`` 2183 Cirrus Logic GD5446 Video card. All Windows versions starting 2184 from Windows 95 should recognize and use this graphic card. For 2185 optimal performances, use 16 bit color depth in the guest and 2186 the host OS. (This card was the default before QEMU 2.2) 2187 2188 ``std`` 2189 Standard VGA card with Bochs VBE extensions. If your guest OS 2190 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2191 you want to use high resolution modes (>= 1280x1024x16) then you 2192 should use this option. (This card is the default since QEMU 2193 2.2) 2194 2195 ``vmware`` 2196 VMWare SVGA-II compatible adapter. Use it if you have 2197 sufficiently recent XFree86/XOrg server or Windows guest with a 2198 driver for this card. 2199 2200 ``qxl`` 2201 QXL paravirtual graphic card. It is VGA compatible (including 2202 VESA 2.0 VBE support). Works best with qxl guest drivers 2203 installed though. Recommended choice when using the spice 2204 protocol. 2205 2206 ``tcx`` 2207 (sun4m only) Sun TCX framebuffer. This is the default 2208 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2209 colour depths at a fixed resolution of 1024x768. 2210 2211 ``cg3`` 2212 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2213 framebuffer for sun4m machines available in both 1024x768 2214 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2215 wishing to run older Solaris versions. 2216 2217 ``virtio`` 2218 Virtio VGA card. 2219 2220 ``none`` 2221 Disable VGA card. 2222ERST 2223 2224DEF("full-screen", 0, QEMU_OPTION_full_screen, 2225 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2226SRST 2227``-full-screen`` 2228 Start in full screen. 2229ERST 2230 2231DEF("g", HAS_ARG, QEMU_OPTION_g , 2232 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2233 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2234SRST 2235``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2236 Set the initial graphical resolution and depth (PPC, SPARC only). 2237 2238 For PPC the default is 800x600x32. 2239 2240 For SPARC with the TCX graphics device, the default is 1024x768x8 2241 with the option of 1024x768x24. For cgthree, the default is 2242 1024x768x8 with the option of 1152x900x8 for people who wish to use 2243 OBP. 2244ERST 2245 2246DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2247 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2248SRST 2249``-vnc display[,option[,option[,...]]]`` 2250 Normally, if QEMU is compiled with graphical window support, it 2251 displays output such as guest graphics, guest console, and the QEMU 2252 monitor in a window. With this option, you can have QEMU listen on 2253 VNC display display and redirect the VGA display over the VNC 2254 session. It is very useful to enable the usb tablet device when 2255 using this option (option ``-device usb-tablet``). When using the 2256 VNC display, you must use the ``-k`` parameter to set the keyboard 2257 layout if you are not using en-us. Valid syntax for the display is 2258 2259 ``to=L`` 2260 With this option, QEMU will try next available VNC displays, 2261 until the number L, if the origianlly defined "-vnc display" is 2262 not available, e.g. port 5900+display is already used by another 2263 application. By default, to=0. 2264 2265 ``host:d`` 2266 TCP connections will only be allowed from host on display d. By 2267 convention the TCP port is 5900+d. Optionally, host can be 2268 omitted in which case the server will accept connections from 2269 any host. 2270 2271 ``unix:path`` 2272 Connections will be allowed over UNIX domain sockets where path 2273 is the location of a unix socket to listen for connections on. 2274 2275 ``none`` 2276 VNC is initialized but not started. The monitor ``change`` 2277 command can be used to later start the VNC server. 2278 2279 Following the display value there may be one or more option flags 2280 separated by commas. Valid options are 2281 2282 ``reverse=on|off`` 2283 Connect to a listening VNC client via a "reverse" connection. 2284 The client is specified by the display. For reverse network 2285 connections (host:d,``reverse``), the d argument is a TCP port 2286 number, not a display number. 2287 2288 ``websocket=on|off`` 2289 Opens an additional TCP listening port dedicated to VNC 2290 Websocket connections. If a bare websocket option is given, the 2291 Websocket port is 5700+display. An alternative port can be 2292 specified with the syntax ``websocket``\ =port. 2293 2294 If host is specified connections will only be allowed from this 2295 host. It is possible to control the websocket listen address 2296 independently, using the syntax ``websocket``\ =host:port. 2297 2298 If no TLS credentials are provided, the websocket connection 2299 runs in unencrypted mode. If TLS credentials are provided, the 2300 websocket connection requires encrypted client connections. 2301 2302 ``password=on|off`` 2303 Require that password based authentication is used for client 2304 connections. 2305 2306 The password must be set separately using the ``set_password`` 2307 command in the :ref:`QEMU monitor`. The 2308 syntax to change your password is: 2309 ``set_password <protocol> <password>`` where <protocol> could be 2310 either "vnc" or "spice". 2311 2312 If you would like to change <protocol> password expiration, you 2313 should use ``expire_password <protocol> <expiration-time>`` 2314 where expiration time could be one of the following options: 2315 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2316 make password expire in 60 seconds, or 1335196800 to make 2317 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2318 this date and time). 2319 2320 You can also use keywords "now" or "never" for the expiration 2321 time to allow <protocol> password to expire immediately or never 2322 expire. 2323 2324 ``password-secret=<secret-id>`` 2325 Require that password based authentication is used for client 2326 connections, using the password provided by the ``secret`` 2327 object identified by ``secret-id``. 2328 2329 ``tls-creds=ID`` 2330 Provides the ID of a set of TLS credentials to use to secure the 2331 VNC server. They will apply to both the normal VNC server socket 2332 and the websocket socket (if enabled). Setting TLS credentials 2333 will cause the VNC server socket to enable the VeNCrypt auth 2334 mechanism. The credentials should have been previously created 2335 using the ``-object tls-creds`` argument. 2336 2337 ``tls-authz=ID`` 2338 Provides the ID of the QAuthZ authorization object against which 2339 the client's x509 distinguished name will validated. This object 2340 is only resolved at time of use, so can be deleted and recreated 2341 on the fly while the VNC server is active. If missing, it will 2342 default to denying access. 2343 2344 ``sasl=on|off`` 2345 Require that the client use SASL to authenticate with the VNC 2346 server. The exact choice of authentication method used is 2347 controlled from the system / user's SASL configuration file for 2348 the 'qemu' service. This is typically found in 2349 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2350 an environment variable SASL\_CONF\_PATH can be used to make it 2351 search alternate locations for the service config. While some 2352 SASL auth methods can also provide data encryption (eg GSSAPI), 2353 it is recommended that SASL always be combined with the 'tls' 2354 and 'x509' settings to enable use of SSL and server 2355 certificates. This ensures a data encryption preventing 2356 compromise of authentication credentials. See the 2357 :ref:`VNC security` section in the System Emulation Users Guide 2358 for details on using SASL authentication. 2359 2360 ``sasl-authz=ID`` 2361 Provides the ID of the QAuthZ authorization object against which 2362 the client's SASL username will validated. This object is only 2363 resolved at time of use, so can be deleted and recreated on the 2364 fly while the VNC server is active. If missing, it will default 2365 to denying access. 2366 2367 ``acl=on|off`` 2368 Legacy method for enabling authorization of clients against the 2369 x509 distinguished name and SASL username. It results in the 2370 creation of two ``authz-list`` objects with IDs of 2371 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2372 objects must be configured with the HMP ACL commands. 2373 2374 This option is deprecated and should no longer be used. The new 2375 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2376 2377 ``lossy=on|off`` 2378 Enable lossy compression methods (gradient, JPEG, ...). If this 2379 option is set, VNC client may receive lossy framebuffer updates 2380 depending on its encoding settings. Enabling this option can 2381 save a lot of bandwidth at the expense of quality. 2382 2383 ``non-adaptive=on|off`` 2384 Disable adaptive encodings. Adaptive encodings are enabled by 2385 default. An adaptive encoding will try to detect frequently 2386 updated screen regions, and send updates in these regions using 2387 a lossy encoding (like JPEG). This can be really helpful to save 2388 bandwidth when playing videos. Disabling adaptive encodings 2389 restores the original static behavior of encodings like Tight. 2390 2391 ``share=[allow-exclusive|force-shared|ignore]`` 2392 Set display sharing policy. 'allow-exclusive' allows clients to 2393 ask for exclusive access. As suggested by the rfb spec this is 2394 implemented by dropping other connections. Connecting multiple 2395 clients in parallel requires all clients asking for a shared 2396 session (vncviewer: -shared switch). This is the default. 2397 'force-shared' disables exclusive client access. Useful for 2398 shared desktop sessions, where you don't want someone forgetting 2399 specify -shared disconnect everybody else. 'ignore' completely 2400 ignores the shared flag and allows everybody connect 2401 unconditionally. Doesn't conform to the rfb spec but is 2402 traditional QEMU behavior. 2403 2404 ``key-delay-ms`` 2405 Set keyboard delay, for key down and key up events, in 2406 milliseconds. Default is 10. Keyboards are low-bandwidth 2407 devices, so this slowdown can help the device and guest to keep 2408 up and not lose events in case events are arriving in bulk. 2409 Possible causes for the latter are flaky network connections, or 2410 scripts for automated testing. 2411 2412 ``audiodev=audiodev`` 2413 Use the specified audiodev when the VNC client requests audio 2414 transmission. When not using an -audiodev argument, this option 2415 must be omitted, otherwise is must be present and specify a 2416 valid audiodev. 2417 2418 ``power-control=on|off`` 2419 Permit the remote client to issue shutdown, reboot or reset power 2420 control requests. 2421ERST 2422 2423ARCHHEADING(, QEMU_ARCH_I386) 2424 2425ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2426 2427DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2428 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2429 QEMU_ARCH_I386) 2430SRST 2431``-win2k-hack`` 2432 Use it when installing Windows 2000 to avoid a disk full bug. After 2433 Windows 2000 is installed, you no longer need this option (this 2434 option slows down the IDE transfers). 2435ERST 2436 2437DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2438 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2439 QEMU_ARCH_I386) 2440SRST 2441``-no-fd-bootchk`` 2442 Disable boot signature checking for floppy disks in BIOS. May be 2443 needed to boot from old floppy disks. 2444ERST 2445 2446DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2447 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2448SRST 2449``-no-acpi`` 2450 Disable ACPI (Advanced Configuration and Power Interface) support. 2451 Use it if your guest OS complains about ACPI problems (PC target 2452 machine only). 2453ERST 2454 2455DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2456 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2457SRST 2458``-no-hpet`` 2459 Disable HPET support. 2460ERST 2461 2462DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2463 "-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" 2464 " ACPI table description\n", QEMU_ARCH_I386) 2465SRST 2466``-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]...]`` 2467 Add ACPI table with specified header fields and context from 2468 specified files. For file=, take whole ACPI table from the specified 2469 files, including all ACPI headers (possible overridden by other 2470 options). For data=, only data portion of the table is used, all 2471 header information is specified in the command line. If a SLIC table 2472 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2473 fields will override the same in the RSDT and the FADT (a.k.a. 2474 FACP), in order to ensure the field matches required by the 2475 Microsoft SLIC spec and the ACPI spec. 2476ERST 2477 2478DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2479 "-smbios file=binary\n" 2480 " load SMBIOS entry from binary file\n" 2481 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2482 " [,uefi=on|off]\n" 2483 " specify SMBIOS type 0 fields\n" 2484 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2485 " [,uuid=uuid][,sku=str][,family=str]\n" 2486 " specify SMBIOS type 1 fields\n" 2487 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2488 " [,asset=str][,location=str]\n" 2489 " specify SMBIOS type 2 fields\n" 2490 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2491 " [,sku=str]\n" 2492 " specify SMBIOS type 3 fields\n" 2493 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2494 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2495 " specify SMBIOS type 4 fields\n" 2496 "-smbios type=11[,value=str][,path=filename]\n" 2497 " specify SMBIOS type 11 fields\n" 2498 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2499 " [,asset=str][,part=str][,speed=%d]\n" 2500 " specify SMBIOS type 17 fields\n" 2501 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2502 " specify SMBIOS type 41 fields\n", 2503 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2504SRST 2505``-smbios file=binary`` 2506 Load SMBIOS entry from binary file. 2507 2508``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2509 Specify SMBIOS type 0 fields 2510 2511``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2512 Specify SMBIOS type 1 fields 2513 2514``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2515 Specify SMBIOS type 2 fields 2516 2517``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2518 Specify SMBIOS type 3 fields 2519 2520``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2521 Specify SMBIOS type 4 fields 2522 2523``-smbios type=11[,value=str][,path=filename]`` 2524 Specify SMBIOS type 11 fields 2525 2526 This argument can be repeated multiple times, and values are added in the order they are parsed. 2527 Applications intending to use OEM strings data are encouraged to use their application name as 2528 a prefix for the value string. This facilitates passing information for multiple applications 2529 concurrently. 2530 2531 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2532 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2533 2534 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2535 the SMBIOS table in the order in which they appear. 2536 2537 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2538 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2539 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2540 data set, for example, by specifying the serial ID of a block device. 2541 2542 An example passing three strings is 2543 2544 .. parsed-literal:: 2545 2546 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2547 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2548 path=/some/file/with/oemstringsdata.txt 2549 2550 In the guest OS this is visible with the ``dmidecode`` command 2551 2552 .. parsed-literal:: 2553 2554 $ dmidecode -t 11 2555 Handle 0x0E00, DMI type 11, 5 bytes 2556 OEM Strings 2557 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2558 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2559 String 3: myapp:some extra data 2560 2561 2562``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2563 Specify SMBIOS type 17 fields 2564 2565``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2566 Specify SMBIOS type 41 fields 2567 2568 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2569 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2570 position on the PCI bus. 2571 2572 Here is an example of use: 2573 2574 .. parsed-literal:: 2575 2576 -netdev user,id=internet \\ 2577 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2578 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2579 2580 In the guest OS, the device should then appear as ``eno1``: 2581 2582 ..parsed-literal:: 2583 2584 $ ip -brief l 2585 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2586 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2587 2588 Currently, the PCI device has to be attached to the root bus. 2589 2590ERST 2591 2592DEFHEADING() 2593 2594DEFHEADING(Network options:) 2595 2596DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2597#ifdef CONFIG_SLIRP 2598 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2599 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2600 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2601 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2602 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2603#ifndef _WIN32 2604 "[,smb=dir[,smbserver=addr]]\n" 2605#endif 2606 " configure a user mode network backend with ID 'str',\n" 2607 " its DHCP server and optional services\n" 2608#endif 2609#ifdef _WIN32 2610 "-netdev tap,id=str,ifname=name\n" 2611 " configure a host TAP network backend with ID 'str'\n" 2612#else 2613 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2614 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2615 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2616 " [,poll-us=n]\n" 2617 " configure a host TAP network backend with ID 'str'\n" 2618 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2619 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2620 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2621 " to deconfigure it\n" 2622 " use '[down]script=no' to disable script execution\n" 2623 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2624 " configure it\n" 2625 " use 'fd=h' to connect to an already opened TAP interface\n" 2626 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2627 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2628 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2629 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2630 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2631 " use vhost=on to enable experimental in kernel accelerator\n" 2632 " (only has effect for virtio guests which use MSIX)\n" 2633 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2634 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2635 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2636 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2637 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2638 " spent on busy polling for vhost net\n" 2639 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2640 " configure a host TAP network backend with ID 'str' that is\n" 2641 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2642 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2643#endif 2644#ifdef __linux__ 2645 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2646 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2647 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2648 " [,rxcookie=rxcookie][,offset=offset]\n" 2649 " configure a network backend with ID 'str' connected to\n" 2650 " an Ethernet over L2TPv3 pseudowire.\n" 2651 " Linux kernel 3.3+ as well as most routers can talk\n" 2652 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2653 " VM to a router and even VM to Host. It is a nearly-universal\n" 2654 " standard (RFC3931). Note - this implementation uses static\n" 2655 " pre-configured tunnels (same as the Linux kernel).\n" 2656 " use 'src=' to specify source address\n" 2657 " use 'dst=' to specify destination address\n" 2658 " use 'udp=on' to specify udp encapsulation\n" 2659 " use 'srcport=' to specify source udp port\n" 2660 " use 'dstport=' to specify destination udp port\n" 2661 " use 'ipv6=on' to force v6\n" 2662 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2663 " well as a weak security measure\n" 2664 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2665 " use 'txcookie=0x012345678' to specify a txcookie\n" 2666 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2667 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2668 " use 'pincounter=on' to work around broken counter handling in peer\n" 2669 " use 'offset=X' to add an extra offset between header and data\n" 2670#endif 2671 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2672 " configure a network backend to connect to another network\n" 2673 " using a socket connection\n" 2674 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2675 " configure a network backend to connect to a multicast maddr and port\n" 2676 " use 'localaddr=addr' to specify the host address to send packets from\n" 2677 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2678 " configure a network backend to connect to another network\n" 2679 " using an UDP tunnel\n" 2680#ifdef CONFIG_VDE 2681 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2682 " configure a network backend to connect to port 'n' of a vde switch\n" 2683 " running on host and listening for incoming connections on 'socketpath'.\n" 2684 " Use group 'groupname' and mode 'octalmode' to change default\n" 2685 " ownership and permissions for communication port.\n" 2686#endif 2687#ifdef CONFIG_NETMAP 2688 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2689 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2690 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2691 " netmap device, defaults to '/dev/netmap')\n" 2692#endif 2693#ifdef CONFIG_POSIX 2694 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2695 " configure a vhost-user network, backed by a chardev 'dev'\n" 2696#endif 2697#ifdef __linux__ 2698 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2699 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2700#endif 2701 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2702 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2703DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2704 "-nic [tap|bridge|" 2705#ifdef CONFIG_SLIRP 2706 "user|" 2707#endif 2708#ifdef __linux__ 2709 "l2tpv3|" 2710#endif 2711#ifdef CONFIG_VDE 2712 "vde|" 2713#endif 2714#ifdef CONFIG_NETMAP 2715 "netmap|" 2716#endif 2717#ifdef CONFIG_POSIX 2718 "vhost-user|" 2719#endif 2720 "socket][,option][,...][mac=macaddr]\n" 2721 " initialize an on-board / default host NIC (using MAC address\n" 2722 " macaddr) and connect it to the given host network backend\n" 2723 "-nic none use it alone to have zero network devices (the default is to\n" 2724 " provided a 'user' network connection)\n", 2725 QEMU_ARCH_ALL) 2726DEF("net", HAS_ARG, QEMU_OPTION_net, 2727 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2728 " configure or create an on-board (or machine default) NIC and\n" 2729 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2730 "-net [" 2731#ifdef CONFIG_SLIRP 2732 "user|" 2733#endif 2734 "tap|" 2735 "bridge|" 2736#ifdef CONFIG_VDE 2737 "vde|" 2738#endif 2739#ifdef CONFIG_NETMAP 2740 "netmap|" 2741#endif 2742 "socket][,option][,option][,...]\n" 2743 " old way to initialize a host network interface\n" 2744 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2745SRST 2746``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2747 This option is a shortcut for configuring both the on-board 2748 (default) guest NIC hardware and the host network backend in one go. 2749 The host backend options are the same as with the corresponding 2750 ``-netdev`` options below. The guest NIC model can be set with 2751 ``model=modelname``. Use ``model=help`` to list the available device 2752 types. The hardware MAC address can be set with ``mac=macaddr``. 2753 2754 The following two example do exactly the same, to show how ``-nic`` 2755 can be used to shorten the command line length: 2756 2757 .. parsed-literal:: 2758 2759 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2760 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2761 2762``-nic none`` 2763 Indicate that no network devices should be configured. It is used to 2764 override the default configuration (default NIC with "user" host 2765 network backend) which is activated if no other networking options 2766 are provided. 2767 2768``-netdev user,id=id[,option][,option][,...]`` 2769 Configure user mode host network backend which requires no 2770 administrator privilege to run. Valid options are: 2771 2772 ``id=id`` 2773 Assign symbolic name for use in monitor commands. 2774 2775 ``ipv4=on|off and ipv6=on|off`` 2776 Specify that either IPv4 or IPv6 must be enabled. If neither is 2777 specified both protocols are enabled. 2778 2779 ``net=addr[/mask]`` 2780 Set IP network address the guest will see. Optionally specify 2781 the netmask, either in the form a.b.c.d or as number of valid 2782 top-most bits. Default is 10.0.2.0/24. 2783 2784 ``host=addr`` 2785 Specify the guest-visible address of the host. Default is the 2786 2nd IP in the guest network, i.e. x.x.x.2. 2787 2788 ``ipv6-net=addr[/int]`` 2789 Set IPv6 network address the guest will see (default is 2790 fec0::/64). The network prefix is given in the usual hexadecimal 2791 IPv6 address notation. The prefix size is optional, and is given 2792 as the number of valid top-most bits (default is 64). 2793 2794 ``ipv6-host=addr`` 2795 Specify the guest-visible IPv6 address of the host. Default is 2796 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2797 2798 ``restrict=on|off`` 2799 If this option is enabled, the guest will be isolated, i.e. it 2800 will not be able to contact the host and no guest IP packets 2801 will be routed over the host to the outside. This option does 2802 not affect any explicitly set forwarding rules. 2803 2804 ``hostname=name`` 2805 Specifies the client hostname reported by the built-in DHCP 2806 server. 2807 2808 ``dhcpstart=addr`` 2809 Specify the first of the 16 IPs the built-in DHCP server can 2810 assign. Default is the 15th to 31st IP in the guest network, 2811 i.e. x.x.x.15 to x.x.x.31. 2812 2813 ``dns=addr`` 2814 Specify the guest-visible address of the virtual nameserver. The 2815 address must be different from the host address. Default is the 2816 3rd IP in the guest network, i.e. x.x.x.3. 2817 2818 ``ipv6-dns=addr`` 2819 Specify the guest-visible address of the IPv6 virtual 2820 nameserver. The address must be different from the host address. 2821 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2822 2823 ``dnssearch=domain`` 2824 Provides an entry for the domain-search list sent by the 2825 built-in DHCP server. More than one domain suffix can be 2826 transmitted by specifying this option multiple times. If 2827 supported, this will cause the guest to automatically try to 2828 append the given domain suffix(es) in case a domain name can not 2829 be resolved. 2830 2831 Example: 2832 2833 .. parsed-literal:: 2834 2835 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2836 2837 ``domainname=domain`` 2838 Specifies the client domain name reported by the built-in DHCP 2839 server. 2840 2841 ``tftp=dir`` 2842 When using the user mode network stack, activate a built-in TFTP 2843 server. The files in dir will be exposed as the root of a TFTP 2844 server. The TFTP client on the guest must be configured in 2845 binary mode (use the command ``bin`` of the Unix TFTP client). 2846 2847 ``tftp-server-name=name`` 2848 In BOOTP reply, broadcast name as the "TFTP server name" 2849 (RFC2132 option 66). This can be used to advise the guest to 2850 load boot files or configurations from a different server than 2851 the host address. 2852 2853 ``bootfile=file`` 2854 When using the user mode network stack, broadcast file as the 2855 BOOTP filename. In conjunction with ``tftp``, this can be used 2856 to network boot a guest from a local directory. 2857 2858 Example (using pxelinux): 2859 2860 .. parsed-literal:: 2861 2862 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2863 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2864 2865 ``smb=dir[,smbserver=addr]`` 2866 When using the user mode network stack, activate a built-in SMB 2867 server so that Windows OSes can access to the host files in 2868 ``dir`` transparently. The IP address of the SMB server can be 2869 set to addr. By default the 4th IP in the guest network is used, 2870 i.e. x.x.x.4. 2871 2872 In the guest Windows OS, the line: 2873 2874 :: 2875 2876 10.0.2.4 smbserver 2877 2878 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2879 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2880 NT/2000). 2881 2882 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2883 2884 Note that a SAMBA server must be installed on the host OS. 2885 2886 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2887 Redirect incoming TCP or UDP connections to the host port 2888 hostport to the guest IP address guestaddr on guest port 2889 guestport. If guestaddr is not specified, its value is x.x.x.15 2890 (default first address given by the built-in DHCP server). By 2891 specifying hostaddr, the rule can be bound to a specific host 2892 interface. If no connection type is set, TCP is used. This 2893 option can be given multiple times. 2894 2895 For example, to redirect host X11 connection from screen 1 to 2896 guest screen 0, use the following: 2897 2898 .. parsed-literal:: 2899 2900 # on the host 2901 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2902 # this host xterm should open in the guest X11 server 2903 xterm -display :1 2904 2905 To redirect telnet connections from host port 5555 to telnet 2906 port on the guest, use the following: 2907 2908 .. parsed-literal:: 2909 2910 # on the host 2911 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2912 telnet localhost 5555 2913 2914 Then when you use on the host ``telnet localhost 5555``, you 2915 connect to the guest telnet server. 2916 2917 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2918 Forward guest TCP connections to the IP address server on port 2919 port to the character device dev or to a program executed by 2920 cmd:command which gets spawned for each connection. This option 2921 can be given multiple times. 2922 2923 You can either use a chardev directly and have that one used 2924 throughout QEMU's lifetime, like in the following example: 2925 2926 .. parsed-literal:: 2927 2928 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2929 # the guest accesses it 2930 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2931 2932 Or you can execute a command on every TCP connection established 2933 by the guest, so that QEMU behaves similar to an inetd process 2934 for that virtual server: 2935 2936 .. parsed-literal:: 2937 2938 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2939 # and connect the TCP stream to its stdin/stdout 2940 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2941 2942``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2943 Configure a host TAP network backend with ID id. 2944 2945 Use the network script file to configure it and the network script 2946 dfile to deconfigure it. If name is not provided, the OS 2947 automatically provides one. The default network configure script is 2948 ``/etc/qemu-ifup`` and the default network deconfigure script is 2949 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2950 disable script execution. 2951 2952 If running QEMU as an unprivileged user, use the network helper 2953 to configure the TAP interface and attach it to the bridge. 2954 The default network helper executable is 2955 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2956 ``br0``. 2957 2958 ``fd``\ =h can be used to specify the handle of an already opened 2959 host TAP interface. 2960 2961 Examples: 2962 2963 .. parsed-literal:: 2964 2965 #launch a QEMU instance with the default network script 2966 |qemu_system| linux.img -nic tap 2967 2968 .. parsed-literal:: 2969 2970 #launch a QEMU instance with two NICs, each one connected 2971 #to a TAP device 2972 |qemu_system| linux.img \\ 2973 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2974 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2975 2976 .. parsed-literal:: 2977 2978 #launch a QEMU instance with the default network helper to 2979 #connect a TAP device to bridge br0 2980 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2981 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2982 2983``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2984 Connect a host TAP network interface to a host bridge device. 2985 2986 Use the network helper helper to configure the TAP interface and 2987 attach it to the bridge. The default network helper executable is 2988 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2989 ``br0``. 2990 2991 Examples: 2992 2993 .. parsed-literal:: 2994 2995 #launch a QEMU instance with the default network helper to 2996 #connect a TAP device to bridge br0 2997 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2998 2999 .. parsed-literal:: 3000 3001 #launch a QEMU instance with the default network helper to 3002 #connect a TAP device to bridge qemubr0 3003 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3004 3005``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3006 This host network backend can be used to connect the guest's network 3007 to another QEMU virtual machine using a TCP socket connection. If 3008 ``listen`` is specified, QEMU waits for incoming connections on port 3009 (host is optional). ``connect`` is used to connect to another QEMU 3010 instance using the ``listen`` option. ``fd``\ =h specifies an 3011 already opened TCP socket. 3012 3013 Example: 3014 3015 .. parsed-literal:: 3016 3017 # launch a first QEMU instance 3018 |qemu_system| linux.img \\ 3019 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3020 -netdev socket,id=n1,listen=:1234 3021 # connect the network of this instance to the network of the first instance 3022 |qemu_system| linux.img \\ 3023 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3024 -netdev socket,id=n2,connect=127.0.0.1:1234 3025 3026``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3027 Configure a socket host network backend to share the guest's network 3028 traffic with another QEMU virtual machines using a UDP multicast 3029 socket, effectively making a bus for every QEMU with same multicast 3030 address maddr and port. NOTES: 3031 3032 1. Several QEMU can be running on different hosts and share same bus 3033 (assuming correct multicast setup for these hosts). 3034 3035 2. mcast support is compatible with User Mode Linux (argument 3036 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3037 3038 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3039 3040 Example: 3041 3042 .. parsed-literal:: 3043 3044 # launch one QEMU instance 3045 |qemu_system| linux.img \\ 3046 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3047 -netdev socket,id=n1,mcast=230.0.0.1:1234 3048 # launch another QEMU instance on same "bus" 3049 |qemu_system| linux.img \\ 3050 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3051 -netdev socket,id=n2,mcast=230.0.0.1:1234 3052 # launch yet another QEMU instance on same "bus" 3053 |qemu_system| linux.img \\ 3054 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3055 -netdev socket,id=n3,mcast=230.0.0.1:1234 3056 3057 Example (User Mode Linux compat.): 3058 3059 .. parsed-literal:: 3060 3061 # launch QEMU instance (note mcast address selected is UML's default) 3062 |qemu_system| linux.img \\ 3063 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3064 -netdev socket,id=n1,mcast=239.192.168.1:1102 3065 # launch UML 3066 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3067 3068 Example (send packets from host's 1.2.3.4): 3069 3070 .. parsed-literal:: 3071 3072 |qemu_system| linux.img \\ 3073 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3074 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3075 3076``-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]`` 3077 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3078 is a popular protocol to transport Ethernet (and other Layer 2) data 3079 frames between two systems. It is present in routers, firewalls and 3080 the Linux kernel (from version 3.3 onwards). 3081 3082 This transport allows a VM to communicate to another VM, router or 3083 firewall directly. 3084 3085 ``src=srcaddr`` 3086 source address (mandatory) 3087 3088 ``dst=dstaddr`` 3089 destination address (mandatory) 3090 3091 ``udp`` 3092 select udp encapsulation (default is ip). 3093 3094 ``srcport=srcport`` 3095 source udp port. 3096 3097 ``dstport=dstport`` 3098 destination udp port. 3099 3100 ``ipv6`` 3101 force v6, otherwise defaults to v4. 3102 3103 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3104 Cookies are a weak form of security in the l2tpv3 specification. 3105 Their function is mostly to prevent misconfiguration. By default 3106 they are 32 bit. 3107 3108 ``cookie64`` 3109 Set cookie size to 64 bit instead of the default 32 3110 3111 ``counter=off`` 3112 Force a 'cut-down' L2TPv3 with no counter as in 3113 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3114 3115 ``pincounter=on`` 3116 Work around broken counter handling in peer. This may also help 3117 on networks which have packet reorder. 3118 3119 ``offset=offset`` 3120 Add an extra offset between header and data 3121 3122 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3123 the bridge br-lan on the remote Linux host 1.2.3.4: 3124 3125 .. parsed-literal:: 3126 3127 # Setup tunnel on linux host using raw ip as encapsulation 3128 # on 1.2.3.4 3129 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3130 encap udp udp_sport 16384 udp_dport 16384 3131 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3132 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3133 ifconfig vmtunnel0 mtu 1500 3134 ifconfig vmtunnel0 up 3135 brctl addif br-lan vmtunnel0 3136 3137 3138 # on 4.3.2.1 3139 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3140 3141 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3142 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3143 3144``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3145 Configure VDE backend to connect to PORT n of a vde switch running 3146 on host and listening for incoming connections on socketpath. Use 3147 GROUP groupname and MODE octalmode to change default ownership and 3148 permissions for communication port. This option is only available if 3149 QEMU has been compiled with vde support enabled. 3150 3151 Example: 3152 3153 .. parsed-literal:: 3154 3155 # launch vde switch 3156 vde_switch -F -sock /tmp/myswitch 3157 # launch QEMU instance 3158 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3159 3160``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3161 Establish a vhost-user netdev, backed by a chardev id. The chardev 3162 should be a unix domain socket backed one. The vhost-user uses a 3163 specifically defined protocol to pass vhost ioctl replacement 3164 messages to an application on the other end of the socket. On 3165 non-MSIX guests, the feature can be forced with vhostforce. Use 3166 'queues=n' to specify the number of queues to be created for 3167 multiqueue vhost-user. 3168 3169 Example: 3170 3171 :: 3172 3173 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3174 -numa node,memdev=mem \ 3175 -chardev socket,id=chr0,path=/path/to/socket \ 3176 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3177 -device virtio-net-pci,netdev=net0 3178 3179``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3180 Establish a vhost-vdpa netdev. 3181 3182 vDPA device is a device that uses a datapath which complies with 3183 the virtio specifications with a vendor specific control path. 3184 vDPA devices can be both physically located on the hardware or 3185 emulated by software. 3186 3187``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3188 Create a hub port on the emulated hub with ID hubid. 3189 3190 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3191 instead of a single netdev. Alternatively, you can also connect the 3192 hubport to another netdev with ID nd by using the ``netdev=nd`` 3193 option. 3194 3195``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3196 Legacy option to configure or create an on-board (or machine 3197 default) Network Interface Card(NIC) and connect it either to the 3198 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3199 If model is omitted, then the default NIC model associated with the 3200 machine type is used. Note that the default NIC model may change in 3201 future QEMU releases, so it is highly recommended to always specify 3202 a model. Optionally, the MAC address can be changed to mac, the 3203 device address set to addr (PCI cards only), and a name can be 3204 assigned for use in monitor commands. Optionally, for PCI cards, you 3205 can specify the number v of MSI-X vectors that the card should have; 3206 this option currently only affects virtio cards; set v = 0 to 3207 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3208 created. QEMU can emulate several different models of network card. 3209 Use ``-net nic,model=help`` for a list of available devices for your 3210 target. 3211 3212``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3213 Configure a host network backend (with the options corresponding to 3214 the same ``-netdev`` option) and connect it to the emulated hub 0 3215 (the default hub). Use name to specify the name of the hub port. 3216ERST 3217 3218DEFHEADING() 3219 3220DEFHEADING(Character device options:) 3221 3222DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3223 "-chardev help\n" 3224 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3225 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3226 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3227 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3228 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3229 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3230 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3231 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3232 " [,logfile=PATH][,logappend=on|off]\n" 3233 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3234 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3235 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3236 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3237 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3238 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3239#ifdef _WIN32 3240 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3241 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3242#else 3243 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3244 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3245#endif 3246#ifdef CONFIG_BRLAPI 3247 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3248#endif 3249#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3250 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3251 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3252 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3253#endif 3254#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3255 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3256 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3257#endif 3258#if defined(CONFIG_SPICE) 3259 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3260 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3261#endif 3262 , QEMU_ARCH_ALL 3263) 3264 3265SRST 3266The general form of a character device option is: 3267 3268``-chardev backend,id=id[,mux=on|off][,options]`` 3269 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3270 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3271 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3272 ``spicevmc``, ``spiceport``. The specific backend will determine the 3273 applicable options. 3274 3275 Use ``-chardev help`` to print all available chardev backend types. 3276 3277 All devices must have an id, which can be any string up to 127 3278 characters long. It is used to uniquely identify this device in 3279 other command line directives. 3280 3281 A character device may be used in multiplexing mode by multiple 3282 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3283 a "1:N" device, and here the "1" end is your specified chardev 3284 backend, and the "N" end is the various parts of QEMU that can talk 3285 to a chardev. If you create a chardev with ``id=myid`` and 3286 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3287 and you can then configure multiple front ends to use that chardev 3288 ID for their input/output. Up to four different front ends can be 3289 connected to a single multiplexed chardev. (Without multiplexing 3290 enabled, a chardev can only be used by a single front end.) For 3291 instance you could use this to allow a single stdio chardev to be 3292 used by two serial ports and the QEMU monitor: 3293 3294 :: 3295 3296 -chardev stdio,mux=on,id=char0 \ 3297 -mon chardev=char0,mode=readline \ 3298 -serial chardev:char0 \ 3299 -serial chardev:char0 3300 3301 You can have more than one multiplexer in a system configuration; 3302 for instance you could have a TCP port multiplexed between UART 0 3303 and UART 1, and stdio multiplexed between the QEMU monitor and a 3304 parallel port: 3305 3306 :: 3307 3308 -chardev stdio,mux=on,id=char0 \ 3309 -mon chardev=char0,mode=readline \ 3310 -parallel chardev:char0 \ 3311 -chardev tcp,...,mux=on,id=char1 \ 3312 -serial chardev:char1 \ 3313 -serial chardev:char1 3314 3315 When you're using a multiplexed character device, some escape 3316 sequences are interpreted in the input. See the chapter about 3317 :ref:`keys in the character backend multiplexer` in the 3318 System Emulation Users Guide for more details. 3319 3320 Note that some other command line options may implicitly create 3321 multiplexed character backends; for instance ``-serial mon:stdio`` 3322 creates a multiplexed stdio backend connected to the serial port and 3323 the QEMU monitor, and ``-nographic`` also multiplexes the console 3324 and the monitor to stdio. 3325 3326 There is currently no support for multiplexing in the other 3327 direction (where a single QEMU front end takes input and output from 3328 multiple chardevs). 3329 3330 Every backend supports the ``logfile`` option, which supplies the 3331 path to a file to record all data transmitted via the backend. The 3332 ``logappend`` option controls whether the log file will be truncated 3333 or appended to when opened. 3334 3335The available backends are: 3336 3337``-chardev null,id=id`` 3338 A void device. This device will not emit any data, and will drop any 3339 data it receives. The null backend does not take any options. 3340 3341``-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]`` 3342 Create a two-way stream socket, which can be either a TCP or a unix 3343 socket. A unix socket will be created if ``path`` is specified. 3344 Behaviour is undefined if TCP options are specified for a unix 3345 socket. 3346 3347 ``server=on|off`` specifies that the socket shall be a listening socket. 3348 3349 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3350 to connect to a listening socket. 3351 3352 ``telnet=on|off`` specifies that traffic on the socket should interpret 3353 telnet escape sequences. 3354 3355 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3356 communication. 3357 3358 ``reconnect`` sets the timeout for reconnecting on non-server 3359 sockets when the remote end goes away. qemu will delay this many 3360 seconds and then attempt to reconnect. Zero disables reconnecting, 3361 and is the default. 3362 3363 ``tls-creds`` requests enablement of the TLS protocol for 3364 encryption, and specifies the id of the TLS credentials to use for 3365 the handshake. The credentials must be previously created with the 3366 ``-object tls-creds`` argument. 3367 3368 ``tls-auth`` provides the ID of the QAuthZ authorization object 3369 against which the client's x509 distinguished name will be 3370 validated. This object is only resolved at time of use, so can be 3371 deleted and recreated on the fly while the chardev server is active. 3372 If missing, it will default to denying access. 3373 3374 TCP and unix socket options are given below: 3375 3376 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3377 ``host`` for a listening socket specifies the local address to 3378 be bound. For a connecting socket species the remote host to 3379 connect to. ``host`` is optional for listening sockets. If not 3380 specified it defaults to ``0.0.0.0``. 3381 3382 ``port`` for a listening socket specifies the local port to be 3383 bound. For a connecting socket specifies the port on the remote 3384 host to connect to. ``port`` can be given as either a port 3385 number or a service name. ``port`` is required. 3386 3387 ``to`` is only relevant to listening sockets. If it is 3388 specified, and ``port`` cannot be bound, QEMU will attempt to 3389 bind to subsequent ports up to and including ``to`` until it 3390 succeeds. ``to`` must be specified as a port number. 3391 3392 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3393 or IPv6 must be used. If neither is specified the socket may 3394 use either protocol. 3395 3396 ``nodelay=on|off`` disables the Nagle algorithm. 3397 3398 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3399 ``path`` specifies the local path of the unix socket. ``path`` 3400 is required. 3401 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3402 rather than the filesystem. Optional, defaults to false. 3403 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3404 rather than the full sun_path length. Optional, defaults to true. 3405 3406``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3407 Sends all traffic from the guest to a remote host over UDP. 3408 3409 ``host`` specifies the remote host to connect to. If not specified 3410 it defaults to ``localhost``. 3411 3412 ``port`` specifies the port on the remote host to connect to. 3413 ``port`` is required. 3414 3415 ``localaddr`` specifies the local address to bind to. If not 3416 specified it defaults to ``0.0.0.0``. 3417 3418 ``localport`` specifies the local port to bind to. If not specified 3419 any available local port will be used. 3420 3421 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3422 If neither is specified the device may use either protocol. 3423 3424``-chardev msmouse,id=id`` 3425 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3426 does not take any options. 3427 3428``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3429 Connect to a QEMU text console. ``vc`` may optionally be given a 3430 specific size. 3431 3432 ``width`` and ``height`` specify the width and height respectively 3433 of the console, in pixels. 3434 3435 ``cols`` and ``rows`` specify that the console be sized to fit a 3436 text console with the given dimensions. 3437 3438``-chardev ringbuf,id=id[,size=size]`` 3439 Create a ring buffer with fixed size ``size``. size must be a power 3440 of two and defaults to ``64K``. 3441 3442``-chardev file,id=id,path=path`` 3443 Log all traffic received from the guest to a file. 3444 3445 ``path`` specifies the path of the file to be opened. This file will 3446 be created if it does not already exist, and overwritten if it does. 3447 ``path`` is required. 3448 3449``-chardev pipe,id=id,path=path`` 3450 Create a two-way connection to the guest. The behaviour differs 3451 slightly between Windows hosts and other hosts: 3452 3453 On Windows, a single duplex pipe will be created at 3454 ``\\.pipe\path``. 3455 3456 On other hosts, 2 pipes will be created called ``path.in`` and 3457 ``path.out``. Data written to ``path.in`` will be received by the 3458 guest. Data written by the guest can be read from ``path.out``. QEMU 3459 will not create these fifos, and requires them to be present. 3460 3461 ``path`` forms part of the pipe path as described above. ``path`` is 3462 required. 3463 3464``-chardev console,id=id`` 3465 Send traffic from the guest to QEMU's standard output. ``console`` 3466 does not take any options. 3467 3468 ``console`` is only available on Windows hosts. 3469 3470``-chardev serial,id=id,path=path`` 3471 Send traffic from the guest to a serial device on the host. 3472 3473 On Unix hosts serial will actually accept any tty device, not only 3474 serial lines. 3475 3476 ``path`` specifies the name of the serial device to open. 3477 3478``-chardev pty,id=id`` 3479 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3480 does not take any options. 3481 3482 ``pty`` is not available on Windows hosts. 3483 3484``-chardev stdio,id=id[,signal=on|off]`` 3485 Connect to standard input and standard output of the QEMU process. 3486 3487 ``signal`` controls if signals are enabled on the terminal, that 3488 includes exiting QEMU with the key sequence Control-c. This option 3489 is enabled by default, use ``signal=off`` to disable it. 3490 3491``-chardev braille,id=id`` 3492 Connect to a local BrlAPI server. ``braille`` does not take any 3493 options. 3494 3495``-chardev tty,id=id,path=path`` 3496 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3497 and DragonFlyBSD hosts. It is an alias for ``serial``. 3498 3499 ``path`` specifies the path to the tty. ``path`` is required. 3500 3501``-chardev parallel,id=id,path=path`` 3502 \ 3503``-chardev parport,id=id,path=path`` 3504 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3505 hosts. 3506 3507 Connect to a local parallel port. 3508 3509 ``path`` specifies the path to the parallel port device. ``path`` is 3510 required. 3511 3512``-chardev spicevmc,id=id,debug=debug,name=name`` 3513 ``spicevmc`` is only available when spice support is built in. 3514 3515 ``debug`` debug level for spicevmc 3516 3517 ``name`` name of spice channel to connect to 3518 3519 Connect to a spice virtual machine channel, such as vdiport. 3520 3521``-chardev spiceport,id=id,debug=debug,name=name`` 3522 ``spiceport`` is only available when spice support is built in. 3523 3524 ``debug`` debug level for spicevmc 3525 3526 ``name`` name of spice port to connect to 3527 3528 Connect to a spice port, allowing a Spice client to handle the 3529 traffic identified by a name (preferably a fqdn). 3530ERST 3531 3532DEFHEADING() 3533 3534#ifdef CONFIG_TPM 3535DEFHEADING(TPM device options:) 3536 3537DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3538 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3539 " use path to provide path to a character device; default is /dev/tpm0\n" 3540 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3541 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3542 "-tpmdev emulator,id=id,chardev=dev\n" 3543 " configure the TPM device using chardev backend\n", 3544 QEMU_ARCH_ALL) 3545SRST 3546The general form of a TPM device option is: 3547 3548``-tpmdev backend,id=id[,options]`` 3549 The specific backend type will determine the applicable options. The 3550 ``-tpmdev`` option creates the TPM backend and requires a 3551 ``-device`` option that specifies the TPM frontend interface model. 3552 3553 Use ``-tpmdev help`` to print all available TPM backend types. 3554 3555The available backends are: 3556 3557``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3558 (Linux-host only) Enable access to the host's TPM using the 3559 passthrough driver. 3560 3561 ``path`` specifies the path to the host's TPM device, i.e., on a 3562 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3563 default ``/dev/tpm0`` is used. 3564 3565 ``cancel-path`` specifies the path to the host TPM device's sysfs 3566 entry allowing for cancellation of an ongoing TPM command. 3567 ``cancel-path`` is optional and by default QEMU will search for the 3568 sysfs entry to use. 3569 3570 Some notes about using the host's TPM with the passthrough driver: 3571 3572 The TPM device accessed by the passthrough driver must not be used 3573 by any other application on the host. 3574 3575 Since the host's firmware (BIOS/UEFI) has already initialized the 3576 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3577 the TPM again and may therefore not show a TPM-specific menu that 3578 would otherwise allow the user to configure the TPM, e.g., allow the 3579 user to enable/disable or activate/deactivate the TPM. Further, if 3580 TPM ownership is released from within a VM then the host's TPM will 3581 get disabled and deactivated. To enable and activate the TPM again 3582 afterwards, the host has to be rebooted and the user is required to 3583 enter the firmware's menu to enable and activate the TPM. If the TPM 3584 is left disabled and/or deactivated most TPM commands will fail. 3585 3586 To create a passthrough TPM use the following two options: 3587 3588 :: 3589 3590 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3591 3592 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3593 ``tpmdev=tpm0`` in the device option. 3594 3595``-tpmdev emulator,id=id,chardev=dev`` 3596 (Linux-host only) Enable access to a TPM emulator using Unix domain 3597 socket based chardev backend. 3598 3599 ``chardev`` specifies the unique ID of a character device backend 3600 that provides connection to the software TPM server. 3601 3602 To create a TPM emulator backend device with chardev socket backend: 3603 3604 :: 3605 3606 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3607ERST 3608 3609DEFHEADING() 3610 3611#endif 3612 3613DEFHEADING(Linux/Multiboot boot specific:) 3614SRST 3615When using these options, you can use a given Linux or Multiboot kernel 3616without installing it in the disk image. It can be useful for easier 3617testing of various kernels. 3618 3619 3620ERST 3621 3622DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3623 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3624SRST 3625``-kernel bzImage`` 3626 Use bzImage as kernel image. The kernel can be either a Linux kernel 3627 or in multiboot format. 3628ERST 3629 3630DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3631 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3632SRST 3633``-append cmdline`` 3634 Use cmdline as kernel command line 3635ERST 3636 3637DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3638 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3639SRST 3640``-initrd file`` 3641 Use file as initial ram disk. 3642 3643``-initrd "file1 arg=foo,file2"`` 3644 This syntax is only available with multiboot. 3645 3646 Use file1 and file2 as modules and pass arg=foo as parameter to the 3647 first module. 3648ERST 3649 3650DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3651 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3652SRST 3653``-dtb file`` 3654 Use file as a device tree binary (dtb) image and pass it to the 3655 kernel on boot. 3656ERST 3657 3658DEFHEADING() 3659 3660DEFHEADING(Debug/Expert options:) 3661 3662DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3663 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3664 " Policy for handling deprecated management interfaces\n" 3665 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3666 " Policy for handling unstable management interfaces\n", 3667 QEMU_ARCH_ALL) 3668SRST 3669``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3670 Set policy for handling deprecated management interfaces (experimental): 3671 3672 ``deprecated-input=accept`` (default) 3673 Accept deprecated commands and arguments 3674 ``deprecated-input=reject`` 3675 Reject deprecated commands and arguments 3676 ``deprecated-input=crash`` 3677 Crash on deprecated commands and arguments 3678 ``deprecated-output=accept`` (default) 3679 Emit deprecated command results and events 3680 ``deprecated-output=hide`` 3681 Suppress deprecated command results and events 3682 3683 Limitation: covers only syntactic aspects of QMP. 3684 3685``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3686 Set policy for handling unstable management interfaces (experimental): 3687 3688 ``unstable-input=accept`` (default) 3689 Accept unstable commands and arguments 3690 ``unstable-input=reject`` 3691 Reject unstable commands and arguments 3692 ``unstable-input=crash`` 3693 Crash on unstable commands and arguments 3694 ``unstable-output=accept`` (default) 3695 Emit unstable command results and events 3696 ``unstable-output=hide`` 3697 Suppress unstable command results and events 3698 3699 Limitation: covers only syntactic aspects of QMP. 3700ERST 3701 3702DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3703 "-fw_cfg [name=]<name>,file=<file>\n" 3704 " add named fw_cfg entry with contents from file\n" 3705 "-fw_cfg [name=]<name>,string=<str>\n" 3706 " add named fw_cfg entry with contents from string\n", 3707 QEMU_ARCH_ALL) 3708SRST 3709``-fw_cfg [name=]name,file=file`` 3710 Add named fw\_cfg entry with contents from file file. 3711 3712``-fw_cfg [name=]name,string=str`` 3713 Add named fw\_cfg entry with contents from string str. 3714 3715 The terminating NUL character of the contents of str will not be 3716 included as part of the fw\_cfg item data. To insert contents with 3717 embedded NUL characters, you have to use the file parameter. 3718 3719 The fw\_cfg entries are passed by QEMU through to the guest. 3720 3721 Example: 3722 3723 :: 3724 3725 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3726 3727 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3728 from ./my\_blob.bin. 3729ERST 3730 3731DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3732 "-serial dev redirect the serial port to char device 'dev'\n", 3733 QEMU_ARCH_ALL) 3734SRST 3735``-serial dev`` 3736 Redirect the virtual serial port to host character device dev. The 3737 default device is ``vc`` in graphical mode and ``stdio`` in non 3738 graphical mode. 3739 3740 This option can be used several times to simulate up to 4 serial 3741 ports. 3742 3743 Use ``-serial none`` to disable all serial ports. 3744 3745 Available character devices are: 3746 3747 ``vc[:WxH]`` 3748 Virtual console. Optionally, a width and height can be given in 3749 pixel with 3750 3751 :: 3752 3753 vc:800x600 3754 3755 It is also possible to specify width or height in characters: 3756 3757 :: 3758 3759 vc:80Cx24C 3760 3761 ``pty`` 3762 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3763 3764 ``none`` 3765 No device is allocated. 3766 3767 ``null`` 3768 void device 3769 3770 ``chardev:id`` 3771 Use a named character device defined with the ``-chardev`` 3772 option. 3773 3774 ``/dev/XXX`` 3775 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3776 port parameters are set according to the emulated ones. 3777 3778 ``/dev/parportN`` 3779 [Linux only, parallel port only] Use host parallel port N. 3780 Currently SPP and EPP parallel port features can be used. 3781 3782 ``file:filename`` 3783 Write output to filename. No character can be read. 3784 3785 ``stdio`` 3786 [Unix only] standard input/output 3787 3788 ``pipe:filename`` 3789 name pipe filename 3790 3791 ``COMn`` 3792 [Windows only] Use host serial port n 3793 3794 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3795 This implements UDP Net Console. When remote\_host or src\_ip 3796 are not specified they default to ``0.0.0.0``. When not using a 3797 specified src\_port a random port is automatically chosen. 3798 3799 If you just want a simple readonly console you can use 3800 ``netcat`` or ``nc``, by starting QEMU with: 3801 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3802 QEMU writes something to that port it will appear in the 3803 netconsole session. 3804 3805 If you plan to send characters back via netconsole or you want 3806 to stop and start QEMU a lot of times, you should have QEMU use 3807 the same source port each time by using something like ``-serial 3808 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3809 version of netcat which can listen to a TCP port and send and 3810 receive characters via udp. If you have a patched version of 3811 netcat which activates telnet remote echo and single char 3812 transfer, then you can use the following options to set up a 3813 netcat redirector to allow telnet on port 5555 to access the 3814 QEMU port. 3815 3816 ``QEMU Options:`` 3817 -serial udp::4555@:4556 3818 3819 ``netcat options:`` 3820 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3821 3822 ``telnet options:`` 3823 localhost 5555 3824 3825 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3826 The TCP Net Console has two modes of operation. It can send the 3827 serial I/O to a location or wait for a connection from a 3828 location. By default the TCP Net Console is sent to host at the 3829 port. If you use the ``server=on`` option QEMU will wait for a client 3830 socket application to connect to the port before continuing, 3831 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3832 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3833 option only applies if ``server=no`` is set, if the connection goes 3834 down it will attempt to reconnect at the given interval. If host 3835 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3836 time is accepted. You can use ``telnet=on`` to connect to the 3837 corresponding character device. 3838 3839 ``Example to send tcp console to 192.168.0.2 port 4444`` 3840 -serial tcp:192.168.0.2:4444 3841 3842 ``Example to listen and wait on port 4444 for connection`` 3843 -serial tcp::4444,server=on 3844 3845 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3846 -serial tcp:192.168.0.100:4444,server=on,wait=off 3847 3848 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3849 The telnet protocol is used instead of raw tcp sockets. The 3850 options work the same as if you had specified ``-serial tcp``. 3851 The difference is that the port acts like a telnet server or 3852 client using telnet option negotiation. This will also allow you 3853 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3854 supports sending the break sequence. Typically in unix telnet 3855 you do it with Control-] and then type "send break" followed by 3856 pressing the enter key. 3857 3858 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3859 The WebSocket protocol is used instead of raw tcp socket. The 3860 port acts as a WebSocket server. Client mode is not supported. 3861 3862 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3863 A unix domain socket is used instead of a tcp socket. The option 3864 works the same as if you had specified ``-serial tcp`` except 3865 the unix domain socket path is used for connections. 3866 3867 ``mon:dev_string`` 3868 This is a special option to allow the monitor to be multiplexed 3869 onto another serial port. The monitor is accessed with key 3870 sequence of Control-a and then pressing c. dev\_string should be 3871 any one of the serial devices specified above. An example to 3872 multiplex the monitor onto a telnet server listening on port 3873 4444 would be: 3874 3875 ``-serial mon:telnet::4444,server=on,wait=off`` 3876 3877 When the monitor is multiplexed to stdio in this way, Ctrl+C 3878 will not terminate QEMU any more but will be passed to the guest 3879 instead. 3880 3881 ``braille`` 3882 Braille device. This will use BrlAPI to display the braille 3883 output on a real or fake device. 3884 3885 ``msmouse`` 3886 Three button serial mouse. Configure the guest to use Microsoft 3887 protocol. 3888ERST 3889 3890DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3891 "-parallel dev redirect the parallel port to char device 'dev'\n", 3892 QEMU_ARCH_ALL) 3893SRST 3894``-parallel dev`` 3895 Redirect the virtual parallel port to host device dev (same devices 3896 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3897 to use hardware devices connected on the corresponding host parallel 3898 port. 3899 3900 This option can be used several times to simulate up to 3 parallel 3901 ports. 3902 3903 Use ``-parallel none`` to disable all parallel ports. 3904ERST 3905 3906DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3907 "-monitor dev redirect the monitor to char device 'dev'\n", 3908 QEMU_ARCH_ALL) 3909SRST 3910``-monitor dev`` 3911 Redirect the monitor to host device dev (same devices as the serial 3912 port). The default device is ``vc`` in graphical mode and ``stdio`` 3913 in non graphical mode. Use ``-monitor none`` to disable the default 3914 monitor. 3915ERST 3916DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3917 "-qmp dev like -monitor but opens in 'control' mode\n", 3918 QEMU_ARCH_ALL) 3919SRST 3920``-qmp dev`` 3921 Like -monitor but opens in 'control' mode. 3922ERST 3923DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3924 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3925 QEMU_ARCH_ALL) 3926SRST 3927``-qmp-pretty dev`` 3928 Like -qmp but uses pretty JSON formatting. 3929ERST 3930 3931DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3932 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3933SRST 3934``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3935 Setup monitor on chardev name. ``mode=control`` configures 3936 a QMP monitor (a JSON RPC-style protocol) and it is not the 3937 same as HMP, the human monitor that has a "(qemu)" prompt. 3938 ``pretty`` is only valid when ``mode=control``, 3939 turning on JSON pretty printing to ease 3940 human reading and debugging. 3941ERST 3942 3943DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3944 "-debugcon dev redirect the debug console to char device 'dev'\n", 3945 QEMU_ARCH_ALL) 3946SRST 3947``-debugcon dev`` 3948 Redirect the debug console to host device dev (same devices as the 3949 serial port). The debug console is an I/O port which is typically 3950 port 0xe9; writing to that I/O port sends output to this device. The 3951 default device is ``vc`` in graphical mode and ``stdio`` in non 3952 graphical mode. 3953ERST 3954 3955DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3956 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3957SRST 3958``-pidfile file`` 3959 Store the QEMU process PID in file. It is useful if you launch QEMU 3960 from a script. 3961ERST 3962 3963DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3964 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3965SRST 3966``-singlestep`` 3967 Run the emulation in single step mode. 3968ERST 3969 3970DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3971 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3972 QEMU_ARCH_ALL) 3973SRST 3974``--preconfig`` 3975 Pause QEMU for interactive configuration before the machine is 3976 created, which allows querying and configuring properties that will 3977 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3978 exit the preconfig state and move to the next state (i.e. run guest 3979 if -S isn't used or pause the second time if -S is used). This 3980 option is experimental. 3981ERST 3982 3983DEF("S", 0, QEMU_OPTION_S, \ 3984 "-S freeze CPU at startup (use 'c' to start execution)\n", 3985 QEMU_ARCH_ALL) 3986SRST 3987``-S`` 3988 Do not start CPU at startup (you must type 'c' in the monitor). 3989ERST 3990 3991DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3992 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3993 " run qemu with overcommit hints\n" 3994 " mem-lock=on|off controls memory lock support (default: off)\n" 3995 " cpu-pm=on|off controls cpu power management (default: off)\n", 3996 QEMU_ARCH_ALL) 3997SRST 3998``-overcommit mem-lock=on|off`` 3999 \ 4000``-overcommit cpu-pm=on|off`` 4001 Run qemu with hints about host resource overcommit. The default is 4002 to assume that host overcommits all resources. 4003 4004 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4005 (disabled by default). This works when host memory is not 4006 overcommitted and reduces the worst-case latency for guest. 4007 4008 Guest ability to manage power state of host cpus (increasing latency 4009 for other processes on the same host cpu, but decreasing latency for 4010 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4011 works best when host CPU is not overcommitted. When used, host 4012 estimates of CPU cycle and power utilization will be incorrect, not 4013 taking into account guest idle time. 4014ERST 4015 4016DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4017 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4018 " the guest without waiting for gdb to connect; use -S too\n" 4019 " if you want it to not start execution.)\n", 4020 QEMU_ARCH_ALL) 4021SRST 4022``-gdb dev`` 4023 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4024 in the System Emulation Users Guide). Note that this option does not pause QEMU 4025 execution -- if you want QEMU to not start the guest until you 4026 connect with gdb and issue a ``continue`` command, you will need to 4027 also pass the ``-S`` option to QEMU. 4028 4029 The most usual configuration is to listen on a local TCP socket:: 4030 4031 -gdb tcp::3117 4032 4033 but you can specify other backends; UDP, pseudo TTY, or even stdio 4034 are all reasonable use cases. For example, a stdio connection 4035 allows you to start QEMU from within gdb and establish the 4036 connection via a pipe: 4037 4038 .. parsed-literal:: 4039 4040 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4041ERST 4042 4043DEF("s", 0, QEMU_OPTION_s, \ 4044 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4045 QEMU_ARCH_ALL) 4046SRST 4047``-s`` 4048 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4049 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4050ERST 4051 4052DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4053 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4054 QEMU_ARCH_ALL) 4055SRST 4056``-d item1[,...]`` 4057 Enable logging of specified items. Use '-d help' for a list of log 4058 items. 4059ERST 4060 4061DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4062 "-D logfile output log to logfile (default stderr)\n", 4063 QEMU_ARCH_ALL) 4064SRST 4065``-D logfile`` 4066 Output log in logfile instead of to stderr 4067ERST 4068 4069DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4070 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4071 QEMU_ARCH_ALL) 4072SRST 4073``-dfilter range1[,...]`` 4074 Filter debug output to that relevant to a range of target addresses. 4075 The filter spec can be either start+size, start-size or start..end 4076 where start end and size are the addresses and sizes required. For 4077 example: 4078 4079 :: 4080 4081 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4082 4083 Will dump output for any code in the 0x1000 sized block starting at 4084 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4085 another 0x1000 sized block starting at 0xffffffc00005f000. 4086ERST 4087 4088DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4089 "-seed number seed the pseudo-random number generator\n", 4090 QEMU_ARCH_ALL) 4091SRST 4092``-seed number`` 4093 Force the guest to use a deterministic pseudo-random number 4094 generator, seeded with number. This does not affect crypto routines 4095 within the host. 4096ERST 4097 4098DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4099 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4100 QEMU_ARCH_ALL) 4101SRST 4102``-L path`` 4103 Set the directory for the BIOS, VGA BIOS and keymaps. 4104 4105 To list all the data directories, use ``-L help``. 4106ERST 4107 4108DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4109 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4110SRST 4111``-bios file`` 4112 Set the filename for the BIOS. 4113ERST 4114 4115DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4116 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 4117SRST 4118``-enable-kvm`` 4119 Enable KVM full virtualization support. This option is only 4120 available if KVM support is enabled when compiling. 4121ERST 4122 4123DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4124 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 4125DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4126 "-xen-attach attach to existing xen domain\n" 4127 " libxl will use this when starting QEMU\n", 4128 QEMU_ARCH_ALL) 4129DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4130 "-xen-domid-restrict restrict set of available xen operations\n" 4131 " to specified domain id. (Does not affect\n" 4132 " xenpv machine type).\n", 4133 QEMU_ARCH_ALL) 4134SRST 4135``-xen-domid id`` 4136 Specify xen guest domain id (XEN only). 4137 4138``-xen-attach`` 4139 Attach to existing xen domain. libxl will use this when starting 4140 QEMU (XEN only). Restrict set of available xen operations to 4141 specified domain id (XEN only). 4142ERST 4143 4144DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4145 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4146SRST 4147``-no-reboot`` 4148 Exit instead of rebooting. 4149ERST 4150 4151DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4152 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4153SRST 4154``-no-shutdown`` 4155 Don't exit QEMU on guest shutdown, but instead only stop the 4156 emulation. This allows for instance switching to monitor to commit 4157 changes to the disk image. 4158ERST 4159 4160DEF("action", HAS_ARG, QEMU_OPTION_action, 4161 "-action reboot=reset|shutdown\n" 4162 " action when guest reboots [default=reset]\n" 4163 "-action shutdown=poweroff|pause\n" 4164 " action when guest shuts down [default=poweroff]\n" 4165 "-action panic=pause|shutdown|none\n" 4166 " action when guest panics [default=shutdown]\n" 4167 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4168 " action when watchdog fires [default=reset]\n", 4169 QEMU_ARCH_ALL) 4170SRST 4171``-action event=action`` 4172 The action parameter serves to modify QEMU's default behavior when 4173 certain guest events occur. It provides a generic method for specifying the 4174 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4175 parameters. 4176 4177 Examples: 4178 4179 ``-action panic=none`` 4180 ``-action reboot=shutdown,shutdown=pause`` 4181 ``-watchdog i6300esb -action watchdog=pause`` 4182 4183ERST 4184 4185DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4186 "-loadvm [tag|id]\n" \ 4187 " start right away with a saved state (loadvm in monitor)\n", 4188 QEMU_ARCH_ALL) 4189SRST 4190``-loadvm file`` 4191 Start right away with a saved state (``loadvm`` in monitor) 4192ERST 4193 4194#ifndef _WIN32 4195DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4196 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4197#endif 4198SRST 4199``-daemonize`` 4200 Daemonize the QEMU process after initialization. QEMU will not 4201 detach from standard IO until it is ready to receive connections on 4202 any of its devices. This option is a useful way for external 4203 programs to launch QEMU without having to cope with initialization 4204 race conditions. 4205ERST 4206 4207DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4208 "-option-rom rom load a file, rom, into the option ROM space\n", 4209 QEMU_ARCH_ALL) 4210SRST 4211``-option-rom file`` 4212 Load the contents of file as an option ROM. This option is useful to 4213 load things like EtherBoot. 4214ERST 4215 4216DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4217 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4218 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4219 QEMU_ARCH_ALL) 4220 4221SRST 4222``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4223 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4224 the current UTC or local time, respectively. ``localtime`` is 4225 required for correct date in MS-DOS or Windows. To start at a 4226 specific point in time, provide datetime in the format 4227 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4228 4229 By default the RTC is driven by the host system time. This allows 4230 using of the RTC as accurate reference clock inside the guest, 4231 specifically if the host time is smoothly following an accurate 4232 external reference clock, e.g. via NTP. If you want to isolate the 4233 guest time from the host, you can set ``clock`` to ``rt`` instead, 4234 which provides a host monotonic clock if host support it. To even 4235 prevent the RTC from progressing during suspension, you can set 4236 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4237 recommended especially in icount mode in order to preserve 4238 determinism; however, note that in icount mode the speed of the 4239 virtual clock is variable and can in general differ from the host 4240 clock. 4241 4242 Enable ``driftfix`` (i386 targets only) if you experience time drift 4243 problems, specifically with Windows' ACPI HAL. This option will try 4244 to figure out how many timer interrupts were not processed by the 4245 Windows guest and will re-inject them. 4246ERST 4247 4248DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4249 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4250 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4251 " instruction, enable aligning the host and virtual clocks\n" \ 4252 " or disable real time cpu sleeping, and optionally enable\n" \ 4253 " record-and-replay mode\n", QEMU_ARCH_ALL) 4254SRST 4255``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4256 Enable virtual instruction counter. The virtual cpu will execute one 4257 instruction every 2^N ns of virtual time. If ``auto`` is specified 4258 then the virtual cpu speed will be automatically adjusted to keep 4259 virtual time within a few seconds of real time. 4260 4261 Note that while this option can give deterministic behavior, it does 4262 not provide cycle accurate emulation. Modern CPUs contain 4263 superscalar out of order cores with complex cache hierarchies. The 4264 number of instructions executed often has little or no correlation 4265 with actual performance. 4266 4267 When the virtual cpu is sleeping, the virtual time will advance at 4268 default speed unless ``sleep=on`` is specified. With 4269 ``sleep=on``, the virtual time will jump to the next timer 4270 deadline instantly whenever the virtual cpu goes to sleep mode and 4271 will not advance if no timer is enabled. This behavior gives 4272 deterministic execution times from the guest point of view. 4273 The default if icount is enabled is ``sleep=off``. 4274 ``sleep=on`` cannot be used together with either ``shift=auto`` 4275 or ``align=on``. 4276 4277 ``align=on`` will activate the delay algorithm which will try to 4278 synchronise the host clock and the virtual clock. The goal is to 4279 have a guest running at the real frequency imposed by the shift 4280 option. Whenever the guest clock is behind the host clock and if 4281 ``align=on`` is specified then we print a message to the user to 4282 inform about the delay. Currently this option does not work when 4283 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4284 shift values for which the guest clock runs ahead of the host clock. 4285 Typically this happens when the shift value is high (how high 4286 depends on the host machine). The default if icount is enabled 4287 is ``align=off``. 4288 4289 When the ``rr`` option is specified deterministic record/replay is 4290 enabled. The ``rrfile=`` option must also be provided to 4291 specify the path to the replay log. In record mode data is written 4292 to this file, and in replay mode it is read back. 4293 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4294 name. In record mode, a new VM snapshot with the given name is created 4295 at the start of execution recording. In replay mode this option 4296 specifies the snapshot name used to load the initial VM state. 4297ERST 4298 4299DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4300 "-watchdog model\n" \ 4301 " enable virtual hardware watchdog [default=none]\n", 4302 QEMU_ARCH_ALL) 4303SRST 4304``-watchdog model`` 4305 Create a virtual hardware watchdog device. Once enabled (by a guest 4306 action), the watchdog must be periodically polled by an agent inside 4307 the guest or else the guest will be restarted. Choose a model for 4308 which your guest has drivers. 4309 4310 The model is the model of hardware watchdog to emulate. Use 4311 ``-watchdog help`` to list available hardware models. Only one 4312 watchdog can be enabled for a guest. 4313 4314 The following models may be available: 4315 4316 ``ib700`` 4317 iBASE 700 is a very simple ISA watchdog with a single timer. 4318 4319 ``i6300esb`` 4320 Intel 6300ESB I/O controller hub is a much more featureful 4321 PCI-based dual-timer watchdog. 4322 4323 ``diag288`` 4324 A virtual watchdog for s390x backed by the diagnose 288 4325 hypercall (currently KVM only). 4326ERST 4327 4328DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4329 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4330 " action when watchdog fires [default=reset]\n", 4331 QEMU_ARCH_ALL) 4332SRST 4333``-watchdog-action action`` 4334 The action controls what QEMU will do when the watchdog timer 4335 expires. The default is ``reset`` (forcefully reset the guest). 4336 Other possible actions are: ``shutdown`` (attempt to gracefully 4337 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4338 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4339 guest), ``debug`` (print a debug message and continue), or ``none`` 4340 (do nothing). 4341 4342 Note that the ``shutdown`` action requires that the guest responds 4343 to ACPI signals, which it may not be able to do in the sort of 4344 situations where the watchdog would have expired, and thus 4345 ``-watchdog-action shutdown`` is not recommended for production use. 4346 4347 Examples: 4348 4349 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4350 4351ERST 4352 4353DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4354 "-echr chr set terminal escape character instead of ctrl-a\n", 4355 QEMU_ARCH_ALL) 4356SRST 4357``-echr numeric_ascii_value`` 4358 Change the escape character used for switching to the monitor when 4359 using monitor and serial sharing. The default is ``0x01`` when using 4360 the ``-nographic`` option. ``0x01`` is equal to pressing 4361 ``Control-a``. You can select a different character from the ascii 4362 control keys where 1 through 26 map to Control-a through Control-z. 4363 For instance you could use the either of the following to change the 4364 escape character to Control-t. 4365 4366 ``-echr 0x14``; \ ``-echr 20`` 4367 4368ERST 4369 4370DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4371 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4372 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4373 "-incoming unix:socketpath\n" \ 4374 " prepare for incoming migration, listen on\n" \ 4375 " specified protocol and socket address\n" \ 4376 "-incoming fd:fd\n" \ 4377 "-incoming exec:cmdline\n" \ 4378 " accept incoming migration on given file descriptor\n" \ 4379 " or from given external command\n" \ 4380 "-incoming defer\n" \ 4381 " wait for the URI to be specified via migrate_incoming\n", 4382 QEMU_ARCH_ALL) 4383SRST 4384``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4385 \ 4386``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4387 Prepare for incoming migration, listen on a given tcp port. 4388 4389``-incoming unix:socketpath`` 4390 Prepare for incoming migration, listen on a given unix socket. 4391 4392``-incoming fd:fd`` 4393 Accept incoming migration from a given filedescriptor. 4394 4395``-incoming exec:cmdline`` 4396 Accept incoming migration as an output from specified external 4397 command. 4398 4399``-incoming defer`` 4400 Wait for the URI to be specified via migrate\_incoming. The monitor 4401 can be used to change settings (such as migration parameters) prior 4402 to issuing the migrate\_incoming to allow the migration to begin. 4403ERST 4404 4405DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4406 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4407SRST 4408``-only-migratable`` 4409 Only allow migratable devices. Devices will not be allowed to enter 4410 an unmigratable state. 4411ERST 4412 4413DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4414 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4415SRST 4416``-nodefaults`` 4417 Don't create default devices. Normally, QEMU sets the default 4418 devices like serial port, parallel port, virtual console, monitor 4419 device, VGA adapter, floppy and CD-ROM drive and others. The 4420 ``-nodefaults`` option will disable all those default devices. 4421ERST 4422 4423#ifndef _WIN32 4424DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4425 "-chroot dir chroot to dir just before starting the VM\n", 4426 QEMU_ARCH_ALL) 4427#endif 4428SRST 4429``-chroot dir`` 4430 Immediately before starting guest execution, chroot to the specified 4431 directory. Especially useful in combination with -runas. 4432ERST 4433 4434#ifndef _WIN32 4435DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4436 "-runas user change to user id user just before starting the VM\n" \ 4437 " user can be numeric uid:gid instead\n", 4438 QEMU_ARCH_ALL) 4439#endif 4440SRST 4441``-runas user`` 4442 Immediately before starting guest execution, drop root privileges, 4443 switching to the specified user. 4444ERST 4445 4446DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4447 "-prom-env variable=value\n" 4448 " set OpenBIOS nvram variables\n", 4449 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4450SRST 4451``-prom-env variable=value`` 4452 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4453 4454 :: 4455 4456 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4457 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4458 4459 :: 4460 4461 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4462 -prom-env 'boot-device=hd:2,\yaboot' \ 4463 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4464ERST 4465DEF("semihosting", 0, QEMU_OPTION_semihosting, 4466 "-semihosting semihosting mode\n", 4467 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4468 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4469SRST 4470``-semihosting`` 4471 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4472 4473 Note that this allows guest direct access to the host filesystem, so 4474 should only be used with a trusted guest OS. 4475 4476 See the -semihosting-config option documentation for further 4477 information about the facilities this enables. 4478ERST 4479DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4480 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4481 " semihosting configuration\n", 4482QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4483QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4484SRST 4485``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4486 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4487 only). 4488 4489 Note that this allows guest direct access to the host filesystem, so 4490 should only be used with a trusted guest OS. 4491 4492 On Arm this implements the standard semihosting API, version 2.0. 4493 4494 On M68K this implements the "ColdFire GDB" interface used by 4495 libgloss. 4496 4497 Xtensa semihosting provides basic file IO calls, such as 4498 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4499 linux platform "sim" use this interface. 4500 4501 On RISC-V this implements the standard semihosting API, version 0.2. 4502 4503 ``target=native|gdb|auto`` 4504 Defines where the semihosting calls will be addressed, to QEMU 4505 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4506 means ``gdb`` during debug sessions and ``native`` otherwise. 4507 4508 ``chardev=str1`` 4509 Send the output to a chardev backend output for native or auto 4510 output when not in gdb 4511 4512 ``arg=str1,arg=str2,...`` 4513 Allows the user to pass input arguments, and can be used 4514 multiple times to build up a list. The old-style 4515 ``-kernel``/``-append`` method of passing a command line is 4516 still supported for backward compatibility. If both the 4517 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4518 specified, the former is passed to semihosting as it always 4519 takes precedence. 4520ERST 4521DEF("old-param", 0, QEMU_OPTION_old_param, 4522 "-old-param old param mode\n", QEMU_ARCH_ARM) 4523SRST 4524``-old-param`` 4525 Old param mode (ARM only). 4526ERST 4527 4528DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4529 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4530 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4531 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4532 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4533 " by the kernel, but typically no longer used by modern\n" \ 4534 " C library implementations.\n" \ 4535 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4536 " to elevate privileges using set*uid|gid system calls.\n" \ 4537 " The value 'children' will deny set*uid|gid system calls for\n" \ 4538 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4539 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4540 " blocking *fork and execve\n" \ 4541 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4542 QEMU_ARCH_ALL) 4543SRST 4544``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4545 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4546 filtering and 'off' will disable it. The default is 'off'. 4547 4548 ``obsolete=string`` 4549 Enable Obsolete system calls 4550 4551 ``elevateprivileges=string`` 4552 Disable set\*uid\|gid system calls 4553 4554 ``spawn=string`` 4555 Disable \*fork and execve 4556 4557 ``resourcecontrol=string`` 4558 Disable process affinity and schedular priority 4559ERST 4560 4561DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4562 "-readconfig <file>\n", QEMU_ARCH_ALL) 4563SRST 4564``-readconfig file`` 4565 Read device configuration from file. This approach is useful when 4566 you want to spawn QEMU process with many command line options but 4567 you don't want to exceed the command line character limit. 4568ERST 4569DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4570 "-writeconfig <file>\n" 4571 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4572SRST 4573ERST 4574 4575DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4576 "-no-user-config\n" 4577 " do not load default user-provided config files at startup\n", 4578 QEMU_ARCH_ALL) 4579SRST 4580``-no-user-config`` 4581 The ``-no-user-config`` option makes QEMU not load any of the 4582 user-provided config files on sysconfdir. 4583ERST 4584 4585DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4586 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4587 " specify tracing options\n", 4588 QEMU_ARCH_ALL) 4589SRST 4590``-trace [[enable=]pattern][,events=file][,file=file]`` 4591 .. include:: ../qemu-option-trace.rst.inc 4592 4593ERST 4594DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4595 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4596 " load a plugin\n", 4597 QEMU_ARCH_ALL) 4598SRST 4599``-plugin file=file[,argname=argvalue]`` 4600 Load a plugin. 4601 4602 ``file=file`` 4603 Load the given plugin from a shared library file. 4604 4605 ``argname=argvalue`` 4606 Argument passed to the plugin. (Can be given multiple times.) 4607ERST 4608 4609HXCOMM Internal use 4610DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4611DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4612 4613#ifdef __linux__ 4614DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4615 "-enable-fips enable FIPS 140-2 compliance\n", 4616 QEMU_ARCH_ALL) 4617#endif 4618SRST 4619``-enable-fips`` 4620 Enable FIPS 140-2 compliance mode. 4621ERST 4622 4623DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4624 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4625 " control error message format\n" 4626 " timestamp=on enables timestamps (default: off)\n" 4627 " guest-name=on enables guest name prefix but only if\n" 4628 " -name guest option is set (default: off)\n", 4629 QEMU_ARCH_ALL) 4630SRST 4631``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4632 Control error message format. 4633 4634 ``timestamp=on|off`` 4635 Prefix messages with a timestamp. Default is off. 4636 4637 ``guest-name=on|off`` 4638 Prefix messages with guest name but only if -name guest option is set 4639 otherwise the option is ignored. Default is off. 4640ERST 4641 4642DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4643 "-dump-vmstate <file>\n" 4644 " Output vmstate information in JSON format to file.\n" 4645 " Use the scripts/vmstate-static-checker.py file to\n" 4646 " check for possible regressions in migration code\n" 4647 " by comparing two such vmstate dumps.\n", 4648 QEMU_ARCH_ALL) 4649SRST 4650``-dump-vmstate file`` 4651 Dump json-encoded vmstate information for current machine type to 4652 file in file 4653ERST 4654 4655DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4656 "-enable-sync-profile\n" 4657 " enable synchronization profiling\n", 4658 QEMU_ARCH_ALL) 4659SRST 4660``-enable-sync-profile`` 4661 Enable synchronization profiling. 4662ERST 4663 4664DEFHEADING() 4665 4666DEFHEADING(Generic object creation:) 4667 4668DEF("object", HAS_ARG, QEMU_OPTION_object, 4669 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4670 " create a new object of type TYPENAME setting properties\n" 4671 " in the order they are specified. Note that the 'id'\n" 4672 " property must be set. These objects are placed in the\n" 4673 " '/objects' path.\n", 4674 QEMU_ARCH_ALL) 4675SRST 4676``-object typename[,prop1=value1,...]`` 4677 Create a new object of type typename setting properties in the order 4678 they are specified. Note that the 'id' property must be set. These 4679 objects are placed in the '/objects' path. 4680 4681 ``-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`` 4682 Creates a memory file backend object, which can be used to back 4683 the guest RAM with huge pages. 4684 4685 The ``id`` parameter is a unique ID that will be used to 4686 reference this memory region in other parameters, e.g. ``-numa``, 4687 ``-device nvdimm``, etc. 4688 4689 The ``size`` option provides the size of the memory region, and 4690 accepts common suffixes, e.g. ``500M``. 4691 4692 The ``mem-path`` provides the path to either a shared memory or 4693 huge page filesystem mount. 4694 4695 The ``share`` boolean option determines whether the memory 4696 region is marked as private to QEMU, or shared. The latter 4697 allows a co-operating external process to access the QEMU memory 4698 region. 4699 4700 The ``share`` is also required for pvrdma devices due to 4701 limitations in the RDMA API provided by Linux. 4702 4703 Setting share=on might affect the ability to configure NUMA 4704 bindings for the memory backend under some circumstances, see 4705 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4706 source tree for additional details. 4707 4708 Setting the ``discard-data`` boolean option to on indicates that 4709 file contents can be destroyed when QEMU exits, to avoid 4710 unnecessarily flushing data to the backing file. Note that 4711 ``discard-data`` is only an optimization, and QEMU might not 4712 discard file contents if it aborts unexpectedly or is terminated 4713 using SIGKILL. 4714 4715 The ``merge`` boolean option enables memory merge, also known as 4716 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4717 the pages for memory deduplication. 4718 4719 Setting the ``dump`` boolean option to off excludes the memory 4720 from core dumps. This feature is also known as MADV\_DONTDUMP. 4721 4722 The ``prealloc`` boolean option enables memory preallocation. 4723 4724 The ``host-nodes`` option binds the memory range to a list of 4725 NUMA host nodes. 4726 4727 The ``policy`` option sets the NUMA policy to one of the 4728 following values: 4729 4730 ``default`` 4731 default host policy 4732 4733 ``preferred`` 4734 prefer the given host node list for allocation 4735 4736 ``bind`` 4737 restrict memory allocation to the given host node list 4738 4739 ``interleave`` 4740 interleave memory allocations across the given host node 4741 list 4742 4743 The ``align`` option specifies the base address alignment when 4744 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4745 ``2M``. Some backend store specified by ``mem-path`` requires an 4746 alignment different than the default one used by QEMU, eg the 4747 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4748 such cases, users can specify the required alignment via this 4749 option. 4750 4751 The ``pmem`` option specifies whether the backing file specified 4752 by ``mem-path`` is in host persistent memory that can be 4753 accessed using the SNIA NVM programming model (e.g. Intel 4754 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4755 operations to guarantee the persistence of its own writes to 4756 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4757 migration). Also, we will map the backend-file with MAP\_SYNC 4758 flag, which ensures the file metadata is in sync for 4759 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4760 requires support from both the host kernel (since Linux kernel 4761 4.15) and the filesystem of ``mem-path`` mounted with DAX 4762 option. 4763 4764 The ``readonly`` option specifies whether the backing file is opened 4765 read-only or read-write (default). 4766 4767 ``-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`` 4768 Creates a memory backend object, which can be used to back the 4769 guest RAM. Memory backend objects offer more control than the 4770 ``-m`` option that is traditionally used to define guest RAM. 4771 Please refer to ``memory-backend-file`` for a description of the 4772 options. 4773 4774 ``-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`` 4775 Creates an anonymous memory file backend object, which allows 4776 QEMU to share the memory with an external process (e.g. when 4777 using vhost-user). The memory is allocated with memfd and 4778 optional sealing. (Linux only) 4779 4780 The ``seal`` option creates a sealed-file, that will block 4781 further resizing the memory ('on' by default). 4782 4783 The ``hugetlb`` option specify the file to be created resides in 4784 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4785 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4786 the hugetlb page size on systems that support multiple hugetlb 4787 page sizes (it must be a power of 2 value supported by the 4788 system). 4789 4790 In some versions of Linux, the ``hugetlb`` option is 4791 incompatible with the ``seal`` option (requires at least Linux 4792 4.16). 4793 4794 Please refer to ``memory-backend-file`` for a description of the 4795 other options. 4796 4797 The ``share`` boolean option is on by default with memfd. 4798 4799 ``-object rng-builtin,id=id`` 4800 Creates a random number generator backend which obtains entropy 4801 from QEMU builtin functions. The ``id`` parameter is a unique ID 4802 that will be used to reference this entropy backend from the 4803 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4804 uses this RNG backend. 4805 4806 ``-object rng-random,id=id,filename=/dev/random`` 4807 Creates a random number generator backend which obtains entropy 4808 from a device on the host. The ``id`` parameter is a unique ID 4809 that will be used to reference this entropy backend from the 4810 ``virtio-rng`` device. The ``filename`` parameter specifies 4811 which file to obtain entropy from and if omitted defaults to 4812 ``/dev/urandom``. 4813 4814 ``-object rng-egd,id=id,chardev=chardevid`` 4815 Creates a random number generator backend which obtains entropy 4816 from an external daemon running on the host. The ``id`` 4817 parameter is a unique ID that will be used to reference this 4818 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4819 parameter is the unique ID of a character device backend that 4820 provides the connection to the RNG daemon. 4821 4822 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4823 Creates a TLS anonymous credentials object, which can be used to 4824 provide TLS support on network backends. The ``id`` parameter is 4825 a unique ID which network backends will use to access the 4826 credentials. The ``endpoint`` is either ``server`` or ``client`` 4827 depending on whether the QEMU network backend that uses the 4828 credentials will be acting as a client or as a server. If 4829 ``verify-peer`` is enabled (the default) then once the handshake 4830 is completed, the peer credentials will be verified, though this 4831 is a no-op for anonymous credentials. 4832 4833 The dir parameter tells QEMU where to find the credential files. 4834 For server endpoints, this directory may contain a file 4835 dh-params.pem providing diffie-hellman parameters to use for the 4836 TLS server. If the file is missing, QEMU will generate a set of 4837 DH parameters at startup. This is a computationally expensive 4838 operation that consumes random pool entropy, so it is 4839 recommended that a persistent set of parameters be generated 4840 upfront and saved. 4841 4842 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4843 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4844 can be used to provide TLS support on network backends. The 4845 ``id`` parameter is a unique ID which network backends will use 4846 to access the credentials. The ``endpoint`` is either ``server`` 4847 or ``client`` depending on whether the QEMU network backend that 4848 uses the credentials will be acting as a client or as a server. 4849 For clients only, ``username`` is the username which will be 4850 sent to the server. If omitted it defaults to "qemu". 4851 4852 The dir parameter tells QEMU where to find the keys file. It is 4853 called "dir/keys.psk" and contains "username:key" pairs. This 4854 file can most easily be created using the GnuTLS ``psktool`` 4855 program. 4856 4857 For server endpoints, dir may also contain a file dh-params.pem 4858 providing diffie-hellman parameters to use for the TLS server. 4859 If the file is missing, QEMU will generate a set of DH 4860 parameters at startup. This is a computationally expensive 4861 operation that consumes random pool entropy, so it is 4862 recommended that a persistent set of parameters be generated up 4863 front and saved. 4864 4865 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4866 Creates a TLS anonymous credentials object, which can be used to 4867 provide TLS support on network backends. The ``id`` parameter is 4868 a unique ID which network backends will use to access the 4869 credentials. The ``endpoint`` is either ``server`` or ``client`` 4870 depending on whether the QEMU network backend that uses the 4871 credentials will be acting as a client or as a server. If 4872 ``verify-peer`` is enabled (the default) then once the handshake 4873 is completed, the peer credentials will be verified. With x509 4874 certificates, this implies that the clients must be provided 4875 with valid client certificates too. 4876 4877 The dir parameter tells QEMU where to find the credential files. 4878 For server endpoints, this directory may contain a file 4879 dh-params.pem providing diffie-hellman parameters to use for the 4880 TLS server. If the file is missing, QEMU will generate a set of 4881 DH parameters at startup. This is a computationally expensive 4882 operation that consumes random pool entropy, so it is 4883 recommended that a persistent set of parameters be generated 4884 upfront and saved. 4885 4886 For x509 certificate credentials the directory will contain 4887 further files providing the x509 certificates. The certificates 4888 must be stored in PEM format, in filenames ca-cert.pem, 4889 ca-crl.pem (optional), server-cert.pem (only servers), 4890 server-key.pem (only servers), client-cert.pem (only clients), 4891 and client-key.pem (only clients). 4892 4893 For the server-key.pem and client-key.pem files which contain 4894 sensitive private keys, it is possible to use an encrypted 4895 version by providing the passwordid parameter. This provides the 4896 ID of a previously created ``secret`` object containing the 4897 password for decryption. 4898 4899 The priority parameter allows to override the global default 4900 priority used by gnutls. This can be useful if the system 4901 administrator needs to use a weaker set of crypto priorities for 4902 QEMU without potentially forcing the weakness onto all 4903 applications. Or conversely if one wants wants a stronger 4904 default for QEMU than for all other applications, they can do 4905 this through this parameter. Its format is a gnutls priority 4906 string as described at 4907 https://gnutls.org/manual/html_node/Priority-Strings.html. 4908 4909 ``-object tls-cipher-suites,id=id,priority=priority`` 4910 Creates a TLS cipher suites object, which can be used to control 4911 the TLS cipher/protocol algorithms that applications are permitted 4912 to use. 4913 4914 The ``id`` parameter is a unique ID which frontends will use to 4915 access the ordered list of permitted TLS cipher suites from the 4916 host. 4917 4918 The ``priority`` parameter allows to override the global default 4919 priority used by gnutls. This can be useful if the system 4920 administrator needs to use a weaker set of crypto priorities for 4921 QEMU without potentially forcing the weakness onto all 4922 applications. Or conversely if one wants wants a stronger 4923 default for QEMU than for all other applications, they can do 4924 this through this parameter. Its format is a gnutls priority 4925 string as described at 4926 https://gnutls.org/manual/html_node/Priority-Strings.html. 4927 4928 An example of use of this object is to control UEFI HTTPS Boot. 4929 The tls-cipher-suites object exposes the ordered list of permitted 4930 TLS cipher suites from the host side to the guest firmware, via 4931 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4932 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4933 guest-side TLS. 4934 4935 In the following example, the priority at which the host-side policy 4936 is retrieved is given by the ``priority`` property. 4937 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4938 refer to /etc/crypto-policies/back-ends/gnutls.config. 4939 4940 .. parsed-literal:: 4941 4942 # |qemu_system| \\ 4943 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4944 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4945 4946 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4947 Interval t can't be 0, this filter batches the packet delivery: 4948 all packets arriving in a given interval on netdev netdevid are 4949 delayed until the end of the interval. Interval is in 4950 microseconds. ``status`` is optional that indicate whether the 4951 netfilter is on (enabled) or off (disabled), the default status 4952 for netfilter will be 'on'. 4953 4954 queue all\|rx\|tx is an option that can be applied to any 4955 netfilter. 4956 4957 ``all``: the filter is attached both to the receive and the 4958 transmit queue of the netdev (default). 4959 4960 ``rx``: the filter is attached to the receive queue of the 4961 netdev, where it will receive packets sent to the netdev. 4962 4963 ``tx``: the filter is attached to the transmit queue of the 4964 netdev, where it will receive packets sent by the netdev. 4965 4966 position head\|tail\|id=<id> is an option to specify where the 4967 filter should be inserted in the filter list. It can be applied 4968 to any netfilter. 4969 4970 ``head``: the filter is inserted at the head of the filter list, 4971 before any existing filters. 4972 4973 ``tail``: the filter is inserted at the tail of the filter list, 4974 behind any existing filters (default). 4975 4976 ``id=<id>``: the filter is inserted before or behind the filter 4977 specified by <id>, see the insert option below. 4978 4979 insert behind\|before is an option to specify where to insert 4980 the new filter relative to the one specified with 4981 position=id=<id>. It can be applied to any netfilter. 4982 4983 ``before``: insert before the specified filter. 4984 4985 ``behind``: insert behind the specified filter (default). 4986 4987 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4988 filter-mirror on netdev netdevid,mirror net packet to 4989 chardevchardevid, if it has the vnet\_hdr\_support flag, 4990 filter-mirror will mirror packet with vnet\_hdr\_len. 4991 4992 ``-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]`` 4993 filter-redirector on netdev netdevid,redirect filter's net 4994 packet to chardev chardevid,and redirect indev's packet to 4995 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4996 will redirect packet with vnet\_hdr\_len. Create a 4997 filter-redirector we need to differ outdev id from indev id, id 4998 can not be the same. we can just use indev or outdev, but at 4999 least one of indev or outdev need to be specified. 5000 5001 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5002 Filter-rewriter is a part of COLO project.It will rewrite tcp 5003 packet to secondary from primary to keep secondary tcp 5004 connection,and rewrite tcp packet to primary from secondary make 5005 tcp packet can be handled by client.if it has the 5006 vnet\_hdr\_support flag, we can parse packet with vnet header. 5007 5008 usage: colo secondary: -object 5009 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5010 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5011 filter-rewriter,id=rew0,netdev=hn0,queue=all 5012 5013 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5014 Dump the network traffic on netdev dev to the file specified by 5015 filename. At most len bytes (64k by default) per packet are 5016 stored. The file format is libpcap, so it can be analyzed with 5017 tools such as tcpdump or Wireshark. 5018 5019 ``-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}]`` 5020 Colo-compare gets packet from primary\_in chardevid and 5021 secondary\_in, then compare whether the payload of primary packet 5022 and secondary packet are the same. If same, it will output 5023 primary packet to out\_dev, else it will notify COLO-framework to do 5024 checkpoint and send primary packet to out\_dev. In order to 5025 improve efficiency, we need to put the task of comparison in 5026 another iothread. If it has the vnet\_hdr\_support flag, 5027 colo compare will send/recv packet with vnet\_hdr\_len. 5028 The compare\_timeout=@var{ms} determines the maximum time of the 5029 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5030 is to set the period of scanning expired primary node network packets. 5031 The max\_queue\_size=@var{size} is to set the max compare queue 5032 size depend on user environment. 5033 If user want to use Xen COLO, need to add the notify\_dev to 5034 notify Xen colo-frame to do checkpoint. 5035 5036 COLO-compare must be used with the help of filter-mirror, 5037 filter-redirector and filter-rewriter. 5038 5039 :: 5040 5041 KVM COLO 5042 5043 primary: 5044 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5045 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5046 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5047 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5048 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5049 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5050 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5051 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5052 -object iothread,id=iothread1 5053 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5054 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5055 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5056 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5057 5058 secondary: 5059 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5060 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5061 -chardev socket,id=red0,host=3.3.3.3,port=9003 5062 -chardev socket,id=red1,host=3.3.3.3,port=9004 5063 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5064 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5065 5066 5067 Xen COLO 5068 5069 primary: 5070 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5071 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5072 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5073 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5074 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5075 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5076 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5077 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5078 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5079 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5080 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5081 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5082 -object iothread,id=iothread1 5083 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5084 5085 secondary: 5086 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5087 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5088 -chardev socket,id=red0,host=3.3.3.3,port=9003 5089 -chardev socket,id=red1,host=3.3.3.3,port=9004 5090 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5091 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5092 5093 If you want to know the detail of above command line, you can 5094 read the colo-compare git log. 5095 5096 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5097 Creates a cryptodev backend which executes crypto opreation from 5098 the QEMU cipher APIS. The id parameter is a unique ID that will 5099 be used to reference this cryptodev backend from the 5100 ``virtio-crypto`` device. The queues parameter is optional, 5101 which specify the queue number of cryptodev backend, the default 5102 of queues is 1. 5103 5104 .. parsed-literal:: 5105 5106 # |qemu_system| \\ 5107 [...] \\ 5108 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5109 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5110 [...] 5111 5112 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5113 Creates a vhost-user cryptodev backend, backed by a chardev 5114 chardevid. The id parameter is a unique ID that will be used to 5115 reference this cryptodev backend from the ``virtio-crypto`` 5116 device. The chardev should be a unix domain socket backed one. 5117 The vhost-user uses a specifically defined protocol to pass 5118 vhost ioctl replacement messages to an application on the other 5119 end of the socket. The queues parameter is optional, which 5120 specify the queue number of cryptodev backend for multiqueue 5121 vhost-user, the default of queues is 1. 5122 5123 .. parsed-literal:: 5124 5125 # |qemu_system| \\ 5126 [...] \\ 5127 -chardev socket,id=chardev0,path=/path/to/socket \\ 5128 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5129 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5130 [...] 5131 5132 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5133 \ 5134 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5135 Defines a secret to store a password, encryption key, or some 5136 other sensitive data. The sensitive data can either be passed 5137 directly via the data parameter, or indirectly via the file 5138 parameter. Using the data parameter is insecure unless the 5139 sensitive data is encrypted. 5140 5141 The sensitive data can be provided in raw format (the default), 5142 or base64. When encoded as JSON, the raw format only supports 5143 valid UTF-8 characters, so base64 is recommended for sending 5144 binary data. QEMU will convert from which ever format is 5145 provided to the format it needs internally. eg, an RBD password 5146 can be provided in raw format, even though it will be base64 5147 encoded when passed onto the RBD sever. 5148 5149 For added protection, it is possible to encrypt the data 5150 associated with a secret using the AES-256-CBC cipher. Use of 5151 encryption is indicated by providing the keyid and iv 5152 parameters. The keyid parameter provides the ID of a previously 5153 defined secret that contains the AES-256 decryption key. This 5154 key should be 32-bytes long and be base64 encoded. The iv 5155 parameter provides the random initialization vector used for 5156 encryption of this particular secret and should be a base64 5157 encrypted string of the 16-byte IV. 5158 5159 The simplest (insecure) usage is to provide the secret inline 5160 5161 .. parsed-literal:: 5162 5163 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5164 5165 The simplest secure usage is to provide the secret via a file 5166 5167 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5168 secret,id=sec0,file=mypasswd.txt,format=raw 5169 5170 For greater security, AES-256-CBC should be used. To illustrate 5171 usage, consider the openssl command line tool which can encrypt 5172 the data. Note that when encrypting, the plaintext must be 5173 padded to the cipher block size (32 bytes) using the standard 5174 PKCS#5/6 compatible padding algorithm. 5175 5176 First a master key needs to be created in base64 encoding: 5177 5178 :: 5179 5180 # openssl rand -base64 32 > key.b64 5181 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5182 5183 Each secret to be encrypted needs to have a random 5184 initialization vector generated. These do not need to be kept 5185 secret 5186 5187 :: 5188 5189 # openssl rand -base64 16 > iv.b64 5190 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5191 5192 The secret to be defined can now be encrypted, in this case 5193 we're telling openssl to base64 encode the result, but it could 5194 be left as raw bytes if desired. 5195 5196 :: 5197 5198 # SECRET=$(printf "letmein" | 5199 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5200 5201 When launching QEMU, create a master secret pointing to 5202 ``key.b64`` and specify that to be used to decrypt the user 5203 password. Pass the contents of ``iv.b64`` to the second secret 5204 5205 .. parsed-literal:: 5206 5207 # |qemu_system| \\ 5208 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5209 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5210 data=$SECRET,iv=$(<iv.b64) 5211 5212 ``-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,kernel-hashes=on|off]`` 5213 Create a Secure Encrypted Virtualization (SEV) guest object, 5214 which can be used to provide the guest memory encryption support 5215 on AMD processors. 5216 5217 When memory encryption is enabled, one of the physical address 5218 bit (aka the C-bit) is utilized to mark if a memory page is 5219 protected. The ``cbitpos`` is used to provide the C-bit 5220 position. The C-bit position is Host family dependent hence user 5221 must provide this value. On EPYC, the value should be 47. 5222 5223 When memory encryption is enabled, we loose certain bits in 5224 physical address space. The ``reduced-phys-bits`` is used to 5225 provide the number of bits we loose in physical address space. 5226 Similar to C-bit, the value is Host family dependent. On EPYC, 5227 the value should be 5. 5228 5229 The ``sev-device`` provides the device file to use for 5230 communicating with the SEV firmware running inside AMD Secure 5231 Processor. The default device is '/dev/sev'. If hardware 5232 supports memory encryption then /dev/sev devices are created by 5233 CCP driver. 5234 5235 The ``policy`` provides the guest policy to be enforced by the 5236 SEV firmware and restrict what configuration and operational 5237 commands can be performed on this guest by the hypervisor. The 5238 policy should be provided by the guest owner and is bound to the 5239 guest and cannot be changed throughout the lifetime of the 5240 guest. The default is 0. 5241 5242 If guest ``policy`` allows sharing the key with another SEV 5243 guest then ``handle`` can be use to provide handle of the guest 5244 from which to share the key. 5245 5246 The ``dh-cert-file`` and ``session-file`` provides the guest 5247 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5248 and session parameters are used for establishing a cryptographic 5249 session with the guest owner to negotiate keys used for 5250 attestation. The file must be encoded in base64. 5251 5252 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5253 cmdline to a designated guest firmware page for measured Linux 5254 boot with -kernel. The default is off. (Since 6.2) 5255 5256 e.g to launch a SEV guest 5257 5258 .. parsed-literal:: 5259 5260 # |qemu_system_x86| \\ 5261 ...... \\ 5262 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5263 -machine ...,memory-encryption=sev0 \\ 5264 ..... 5265 5266 ``-object authz-simple,id=id,identity=string`` 5267 Create an authorization object that will control access to 5268 network services. 5269 5270 The ``identity`` parameter is identifies the user and its format 5271 depends on the network service that authorization object is 5272 associated with. For authorizing based on TLS x509 certificates, 5273 the identity must be the x509 distinguished name. Note that care 5274 must be taken to escape any commas in the distinguished name. 5275 5276 An example authorization object to validate a x509 distinguished 5277 name would look like: 5278 5279 .. parsed-literal:: 5280 5281 # |qemu_system| \\ 5282 ... \\ 5283 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5284 ... 5285 5286 Note the use of quotes due to the x509 distinguished name 5287 containing whitespace, and escaping of ','. 5288 5289 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5290 Create an authorization object that will control access to 5291 network services. 5292 5293 The ``filename`` parameter is the fully qualified path to a file 5294 containing the access control list rules in JSON format. 5295 5296 An example set of rules that match against SASL usernames might 5297 look like: 5298 5299 :: 5300 5301 { 5302 "rules": [ 5303 { "match": "fred", "policy": "allow", "format": "exact" }, 5304 { "match": "bob", "policy": "allow", "format": "exact" }, 5305 { "match": "danb", "policy": "deny", "format": "glob" }, 5306 { "match": "dan*", "policy": "allow", "format": "exact" }, 5307 ], 5308 "policy": "deny" 5309 } 5310 5311 When checking access the object will iterate over all the rules 5312 and the first rule to match will have its ``policy`` value 5313 returned as the result. If no rules match, then the default 5314 ``policy`` value is returned. 5315 5316 The rules can either be an exact string match, or they can use 5317 the simple UNIX glob pattern matching to allow wildcards to be 5318 used. 5319 5320 If ``refresh`` is set to true the file will be monitored and 5321 automatically reloaded whenever its content changes. 5322 5323 As with the ``authz-simple`` object, the format of the identity 5324 strings being matched depends on the network service, but is 5325 usually a TLS x509 distinguished name, or a SASL username. 5326 5327 An example authorization object to validate a SASL username 5328 would look like: 5329 5330 .. parsed-literal:: 5331 5332 # |qemu_system| \\ 5333 ... \\ 5334 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5335 ... 5336 5337 ``-object authz-pam,id=id,service=string`` 5338 Create an authorization object that will control access to 5339 network services. 5340 5341 The ``service`` parameter provides the name of a PAM service to 5342 use for authorization. It requires that a file 5343 ``/etc/pam.d/service`` exist to provide the configuration for 5344 the ``account`` subsystem. 5345 5346 An example authorization object to validate a TLS x509 5347 distinguished name would look like: 5348 5349 .. parsed-literal:: 5350 5351 # |qemu_system| \\ 5352 ... \\ 5353 -object authz-pam,id=auth0,service=qemu-vnc \\ 5354 ... 5355 5356 There would then be a corresponding config file for PAM at 5357 ``/etc/pam.d/qemu-vnc`` that contains: 5358 5359 :: 5360 5361 account requisite pam_listfile.so item=user sense=allow \ 5362 file=/etc/qemu/vnc.allow 5363 5364 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5365 of x509 distingished names that are permitted access 5366 5367 :: 5368 5369 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5370 5371 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5372 Creates a dedicated event loop thread that devices can be 5373 assigned to. This is known as an IOThread. By default device 5374 emulation happens in vCPU threads or the main event loop thread. 5375 This can become a scalability bottleneck. IOThreads allow device 5376 emulation and I/O to run on other host CPUs. 5377 5378 The ``id`` parameter is a unique ID that will be used to 5379 reference this IOThread from ``-device ...,iothread=id``. 5380 Multiple devices can be assigned to an IOThread. Note that not 5381 all devices support an ``iothread`` parameter. 5382 5383 The ``query-iothreads`` QMP command lists IOThreads and reports 5384 their thread IDs so that the user can configure host CPU 5385 pinning/affinity. 5386 5387 IOThreads use an adaptive polling algorithm to reduce event loop 5388 latency. Instead of entering a blocking system call to monitor 5389 file descriptors and then pay the cost of being woken up when an 5390 event occurs, the polling algorithm spins waiting for events for 5391 a short time. The algorithm's default parameters are suitable 5392 for many cases but can be adjusted based on knowledge of the 5393 workload and/or host device latency. 5394 5395 The ``poll-max-ns`` parameter is the maximum number of 5396 nanoseconds to busy wait for events. Polling can be disabled by 5397 setting this value to 0. 5398 5399 The ``poll-grow`` parameter is the multiplier used to increase 5400 the polling time when the algorithm detects it is missing events 5401 due to not polling long enough. 5402 5403 The ``poll-shrink`` parameter is the divisor used to decrease 5404 the polling time when the algorithm detects it is spending too 5405 long polling without encountering events. 5406 5407 The ``aio-max-batch`` parameter is the maximum number of requests 5408 in a batch for the AIO engine, 0 means that the engine will use 5409 its default. 5410 5411 The IOThread parameters can be modified at run-time using the 5412 ``qom-set`` command (where ``iothread1`` is the IOThread's 5413 ``id``): 5414 5415 :: 5416 5417 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5418ERST 5419 5420 5421HXCOMM This is the last statement. Insert new options before this line! 5422 5423#undef DEF 5424#undef DEFHEADING 5425#undef ARCHHEADING 5426
