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][,clusters=clusters][,cores=cores][,threads=threads]\n" 210 " set the number of initial 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 sockets on the machine board\n" 214 " dies= number of dies in one socket\n" 215 " clusters= number of clusters in one die\n" 216 " cores= number of cores in one cluster\n" 217 " threads= number of threads in one core\n" 218 "Note: Different machines may have different subsets of the CPU topology\n" 219 " parameters supported, so the actual meaning of the supported parameters\n" 220 " will vary accordingly. For example, for a machine type that supports a\n" 221 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 222 " sequentially mean as below:\n" 223 " sockets means the number of sockets on the machine board\n" 224 " cores means the number of cores in one socket\n" 225 " threads means the number of threads in one core\n" 226 " For a particular machine type board, an expected CPU topology hierarchy\n" 227 " can be defined through the supported sub-option. Unsupported parameters\n" 228 " can also be provided in addition to the sub-option, but their values\n" 229 " must be set as 1 in the purpose of correct parsing.\n", 230 QEMU_ARCH_ALL) 231SRST 232``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 233 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 234 the machine type board. On boards supporting CPU hotplug, the optional 235 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 236 added at runtime. When both parameters are omitted, the maximum number 237 of CPUs will be calculated from the provided topology members and the 238 initial CPU count will match the maximum number. When only one of them 239 is given then the omitted one will be set to its counterpart's value. 240 Both parameters may be specified, but the maximum number of CPUs must 241 be equal to or greater than the initial CPU count. Product of the 242 CPU topology hierarchy must be equal to the maximum number of CPUs. 243 Both parameters are subject to an upper limit that is determined by 244 the specific machine type chosen. 245 246 To control reporting of CPU topology information, values of the topology 247 parameters can be specified. Machines may only support a subset of the 248 parameters and different machines may have different subsets supported 249 which vary depending on capacity of the corresponding CPU targets. So 250 for a particular machine type board, an expected topology hierarchy can 251 be defined through the supported sub-option. Unsupported parameters can 252 also be provided in addition to the sub-option, but their values must be 253 set as 1 in the purpose of correct parsing. 254 255 Either the initial CPU count, or at least one of the topology parameters 256 must be specified. The specified parameters must be greater than zero, 257 explicit configuration like "cpus=0" is not allowed. Values for any 258 omitted parameters will be computed from those which are given. 259 260 For example, the following sub-option defines a CPU topology hierarchy 261 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 262 core) for a machine that only supports sockets/cores/threads. 263 Some members of the option can be omitted but their values will be 264 automatically computed: 265 266 :: 267 268 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 269 270 The following sub-option defines a CPU topology hierarchy (2 sockets 271 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 272 per core) for PC machines which support sockets/dies/cores/threads. 273 Some members of the option can be omitted but their values will be 274 automatically computed: 275 276 :: 277 278 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 279 280 Historically preference was given to the coarsest topology parameters 281 when computing missing values (ie sockets preferred over cores, which 282 were preferred over threads), however, this behaviour is considered 283 liable to change. Prior to 6.2 the preference was sockets over cores 284 over threads. Since 6.2 the preference is cores over sockets over threads. 285 286 For example, the following option defines a machine board with 2 sockets 287 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 288 289 :: 290 291 -smp 2 292ERST 293 294DEF("numa", HAS_ARG, QEMU_OPTION_numa, 295 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 296 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 297 "-numa dist,src=source,dst=destination,val=distance\n" 298 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 299 "-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" 300 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 301 QEMU_ARCH_ALL) 302SRST 303``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 304 \ 305``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 306 \ 307``-numa dist,src=source,dst=destination,val=distance`` 308 \ 309``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 310 \ 311``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 312 \ 313``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 314 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 315 distance from a source node to a destination node. Set the ACPI 316 Heterogeneous Memory Attributes for the given nodes. 317 318 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 319 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 320 contiguous range of CPU indexes (or a single VCPU if lastcpu is 321 omitted). A non-contiguous set of VCPUs can be represented by 322 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 323 omitted on all nodes, VCPUs are automatically split between them. 324 325 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 326 NUMA node: 327 328 :: 329 330 -numa node,cpus=0-2,cpus=5 331 332 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 333 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 334 assign CPU objects to a node using topology layout properties of 335 CPU. The set of properties is machine specific, and depends on used 336 machine type/'\ ``smp``\ ' options. It could be queried with 337 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 338 property specifies node to which CPU object will be assigned, it's 339 required for node to be declared with '\ ``node``\ ' option before 340 it's used with '\ ``cpu``\ ' option. 341 342 For example: 343 344 :: 345 346 -M pc \ 347 -smp 1,sockets=2,maxcpus=2 \ 348 -numa node,nodeid=0 -numa node,nodeid=1 \ 349 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 350 351 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 352 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 353 a given memory backend device to a node. If '\ ``mem``\ ' and 354 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 355 356 357 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 358 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 359 use it. 360 361 '\ ``initiator``\ ' is an additional option that points to an 362 initiator NUMA node that has best performance (the lowest latency or 363 largest bandwidth) to this NUMA node. Note that this option can be 364 set only when the machine property 'hmat' is set to 'on'. 365 366 Following example creates a machine with 2 NUMA nodes, node 0 has 367 CPU. node 1 has only memory, and its initiator is node 0. Note that 368 because node 0 has CPU, by default the initiator of node 0 is itself 369 and must be itself. 370 371 :: 372 373 -machine hmat=on \ 374 -m 2G,slots=2,maxmem=4G \ 375 -object memory-backend-ram,size=1G,id=m0 \ 376 -object memory-backend-ram,size=1G,id=m1 \ 377 -numa node,nodeid=0,memdev=m0 \ 378 -numa node,nodeid=1,memdev=m1,initiator=0 \ 379 -smp 2,sockets=2,maxcpus=2 \ 380 -numa cpu,node-id=0,socket-id=0 \ 381 -numa cpu,node-id=0,socket-id=1 382 383 source and destination are NUMA node IDs. distance is the NUMA 384 distance from source to destination. The distance from a node to 385 itself is always 10. If any pair of nodes is given a distance, then 386 all pairs must be given distances. Although, when distances are only 387 given in one direction for each pair of nodes, then the distances in 388 the opposite directions are assumed to be the same. If, however, an 389 asymmetrical pair of distances is given for even one node pair, then 390 all node pairs must be provided distance values for both directions, 391 even when they are symmetrical. When a node is unreachable from 392 another node, set the pair's distance to 255. 393 394 Note that the -``numa`` option doesn't allocate any of the specified 395 resources, it just assigns existing resources to NUMA nodes. This 396 means that one still has to use the ``-m``, ``-smp`` options to 397 allocate RAM and VCPUs respectively. 398 399 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 400 Information between initiator and target NUMA nodes in ACPI 401 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 402 create memory requests, usually it has one or more processors. 403 Target NUMA node contains addressable memory. 404 405 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 406 the memory hierarchy of the target NUMA node: if hierarchy is 407 'memory', the structure represents the memory performance; if 408 hierarchy is 'first-level\|second-level\|third-level', this 409 structure represents aggregated performance of memory side caches 410 for each domain. type of 'data-type' is type of data represented by 411 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 412 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 413 the target memory; if 'hierarchy' is 414 'first-level\|second-level\|third-level', 'data-type' is 415 'access\|read\|write' hit latency or 'access\|read\|write' hit 416 bandwidth of the target memory side cache. 417 418 lat is latency value in nanoseconds. bw is bandwidth value, the 419 possible value and units are NUM[M\|G\|T], mean that the bandwidth 420 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 421 used suffix). Note that if latency or bandwidth value is 0, means 422 the corresponding latency or bandwidth information is not provided. 423 424 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 425 belongs. size is the size of memory side cache in bytes. level is 426 the cache level described in this structure, note that the cache 427 level 0 should not be used with '\ ``hmat-cache``\ ' option. 428 associativity is the cache associativity, the possible value is 429 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 430 is the write policy. line is the cache Line size in bytes. 431 432 For example, the following options describe 2 NUMA nodes. Node 0 has 433 2 cpus and a ram, node 1 has only a ram. The processors in node 0 434 access memory in node 0 with access-latency 5 nanoseconds, 435 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 436 memory in NUMA node 1 with access-latency 10 nanoseconds, 437 access-bandwidth is 100 MB/s. And for memory side cache information, 438 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 439 policy is write-back, the cache Line size is 8 bytes: 440 441 :: 442 443 -machine hmat=on \ 444 -m 2G \ 445 -object memory-backend-ram,size=1G,id=m0 \ 446 -object memory-backend-ram,size=1G,id=m1 \ 447 -smp 2,sockets=2,maxcpus=2 \ 448 -numa node,nodeid=0,memdev=m0 \ 449 -numa node,nodeid=1,memdev=m1,initiator=0 \ 450 -numa cpu,node-id=0,socket-id=0 \ 451 -numa cpu,node-id=0,socket-id=1 \ 452 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 453 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 454 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 455 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 456 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 457 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 458ERST 459 460DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 461 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 462 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 463SRST 464``-add-fd fd=fd,set=set[,opaque=opaque]`` 465 Add a file descriptor to an fd set. Valid options are: 466 467 ``fd=fd`` 468 This option defines the file descriptor of which a duplicate is 469 added to fd set. The file descriptor cannot be stdin, stdout, or 470 stderr. 471 472 ``set=set`` 473 This option defines the ID of the fd set to add the file 474 descriptor to. 475 476 ``opaque=opaque`` 477 This option defines a free-form string that can be used to 478 describe fd. 479 480 You can open an image using pre-opened file descriptors from an fd 481 set: 482 483 .. parsed-literal:: 484 485 |qemu_system| \\ 486 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 487 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 488 -drive file=/dev/fdset/2,index=0,media=disk 489ERST 490 491DEF("set", HAS_ARG, QEMU_OPTION_set, 492 "-set group.id.arg=value\n" 493 " set <arg> parameter for item <id> of type <group>\n" 494 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 495SRST 496``-set group.id.arg=value`` 497 Set parameter arg for item id of type group 498ERST 499 500DEF("global", HAS_ARG, QEMU_OPTION_global, 501 "-global driver.property=value\n" 502 "-global driver=driver,property=property,value=value\n" 503 " set a global default for a driver property\n", 504 QEMU_ARCH_ALL) 505SRST 506``-global driver.prop=value`` 507 \ 508``-global driver=driver,property=property,value=value`` 509 Set default value of driver's property prop to value, e.g.: 510 511 .. parsed-literal:: 512 513 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 514 515 In particular, you can use this to set driver properties for devices 516 which are created automatically by the machine model. To create a 517 device which is not created automatically and set properties on it, 518 use -``device``. 519 520 -global driver.prop=value is shorthand for -global 521 driver=driver,property=prop,value=value. The longhand syntax works 522 even when driver contains a dot. 523ERST 524 525DEF("boot", HAS_ARG, QEMU_OPTION_boot, 526 "-boot [order=drives][,once=drives][,menu=on|off]\n" 527 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 528 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 529 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 530 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 531 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 532 QEMU_ARCH_ALL) 533SRST 534``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 535 Specify boot order drives as a string of drive letters. Valid drive 536 letters depend on the target architecture. The x86 PC uses: a, b 537 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 538 (Etherboot from network adapter 1-4), hard disk boot is the default. 539 To apply a particular boot order only on the first startup, specify 540 it via ``once``. Note that the ``order`` or ``once`` parameter 541 should not be used together with the ``bootindex`` property of 542 devices, since the firmware implementations normally do not support 543 both at the same time. 544 545 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 546 as firmware/BIOS supports them. The default is non-interactive boot. 547 548 A splash picture could be passed to bios, enabling user to show it 549 as logo, when option splash=sp\_name is given and menu=on, If 550 firmware/BIOS supports them. Currently Seabios for X86 system 551 support it. limitation: The splash file could be a jpeg file or a 552 BMP file in 24 BPP format(true color). The resolution should be 553 supported by the SVGA mode, so the recommended is 320x240, 640x480, 554 800x640. 555 556 A timeout could be passed to bios, guest will pause for rb\_timeout 557 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 558 not reboot, qemu passes '-1' to bios by default. Currently Seabios 559 for X86 system support it. 560 561 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 562 it. This only effects when boot priority is changed by bootindex 563 options. The default is non-strict boot. 564 565 .. parsed-literal:: 566 567 # try to boot from network first, then from hard disk 568 |qemu_system_x86| -boot order=nc 569 # boot from CD-ROM first, switch back to default order after reboot 570 |qemu_system_x86| -boot once=d 571 # boot with a splash picture for 5 seconds. 572 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 573 574 Note: The legacy format '-boot drives' is still supported but its 575 use is discouraged as it may be removed from future versions. 576ERST 577 578DEF("m", HAS_ARG, QEMU_OPTION_m, 579 "-m [size=]megs[,slots=n,maxmem=size]\n" 580 " configure guest RAM\n" 581 " size: initial amount of guest memory\n" 582 " slots: number of hotplug slots (default: none)\n" 583 " maxmem: maximum amount of guest memory (default: none)\n" 584 "NOTE: Some architectures might enforce a specific granularity\n", 585 QEMU_ARCH_ALL) 586SRST 587``-m [size=]megs[,slots=n,maxmem=size]`` 588 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 589 Optionally, a suffix of "M" or "G" can be used to signify a value in 590 megabytes or gigabytes respectively. Optional pair slots, maxmem 591 could be used to set amount of hotpluggable memory slots and maximum 592 amount of memory. Note that maxmem must be aligned to the page size. 593 594 For example, the following command-line sets the guest startup RAM 595 size to 1GB, creates 3 slots to hotplug additional memory and sets 596 the maximum memory the guest can reach to 4GB: 597 598 .. parsed-literal:: 599 600 |qemu_system| -m 1G,slots=3,maxmem=4G 601 602 If slots and maxmem are not specified, memory hotplug won't be 603 enabled and the guest startup RAM will never increase. 604ERST 605 606DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 607 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 608SRST 609``-mem-path path`` 610 Allocate guest RAM from a temporarily created file in path. 611ERST 612 613DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 614 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 615 QEMU_ARCH_ALL) 616SRST 617``-mem-prealloc`` 618 Preallocate memory when using -mem-path. 619ERST 620 621DEF("k", HAS_ARG, QEMU_OPTION_k, 622 "-k language use keyboard layout (for example 'fr' for French)\n", 623 QEMU_ARCH_ALL) 624SRST 625``-k language`` 626 Use keyboard layout language (for example ``fr`` for French). This 627 option is only needed where it is not easy to get raw PC keycodes 628 (e.g. on Macs, with some X11 servers or with a VNC or curses 629 display). You don't normally need to use it on PC/Linux or 630 PC/Windows hosts. 631 632 The available layouts are: 633 634 :: 635 636 ar de-ch es fo fr-ca hu ja mk no pt-br sv 637 da en-gb et fr fr-ch is lt nl pl ru th 638 de en-us fi fr-be hr it lv nl-be pt sl tr 639 640 The default is ``en-us``. 641ERST 642 643 644HXCOMM Deprecated by -audiodev 645DEF("audio-help", 0, QEMU_OPTION_audio_help, 646 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 647 QEMU_ARCH_ALL) 648SRST 649``-audio-help`` 650 Will show the -audiodev equivalent of the currently specified 651 (deprecated) environment variables. 652ERST 653 654DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 655 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 656 " specifies the audio backend to use\n" 657 " id= identifier of the backend\n" 658 " timer-period= timer period in microseconds\n" 659 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 660 " in|out.fixed-settings= use fixed settings for host audio\n" 661 " in|out.frequency= frequency to use with fixed settings\n" 662 " in|out.channels= number of channels to use with fixed settings\n" 663 " in|out.format= sample format to use with fixed settings\n" 664 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 665 " in|out.voices= number of voices to use\n" 666 " in|out.buffer-length= length of buffer in microseconds\n" 667 "-audiodev none,id=id,[,prop[=value][,...]]\n" 668 " dummy driver that discards all output\n" 669#ifdef CONFIG_AUDIO_ALSA 670 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 671 " in|out.dev= name of the audio device to use\n" 672 " in|out.period-length= length of period in microseconds\n" 673 " in|out.try-poll= attempt to use poll mode\n" 674 " threshold= threshold (in microseconds) when playback starts\n" 675#endif 676#ifdef CONFIG_AUDIO_COREAUDIO 677 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 678 " in|out.buffer-count= number of buffers\n" 679#endif 680#ifdef CONFIG_AUDIO_DSOUND 681 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 682 " latency= add extra latency to playback in microseconds\n" 683#endif 684#ifdef CONFIG_AUDIO_OSS 685 "-audiodev oss,id=id[,prop[=value][,...]]\n" 686 " in|out.dev= path of the audio device to use\n" 687 " in|out.buffer-count= number of buffers\n" 688 " in|out.try-poll= attempt to use poll mode\n" 689 " try-mmap= try using memory mapped access\n" 690 " exclusive= open device in exclusive mode\n" 691 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 692#endif 693#ifdef CONFIG_AUDIO_PA 694 "-audiodev pa,id=id[,prop[=value][,...]]\n" 695 " server= PulseAudio server address\n" 696 " in|out.name= source/sink device name\n" 697 " in|out.latency= desired latency in microseconds\n" 698#endif 699#ifdef CONFIG_AUDIO_SDL 700 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 701 " in|out.buffer-count= number of buffers\n" 702#endif 703#ifdef CONFIG_SPICE 704 "-audiodev spice,id=id[,prop[=value][,...]]\n" 705#endif 706#ifdef CONFIG_DBUS_DISPLAY 707 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 708#endif 709 "-audiodev wav,id=id[,prop[=value][,...]]\n" 710 " path= path of wav file to record\n", 711 QEMU_ARCH_ALL) 712SRST 713``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 714 Adds a new audio backend driver identified by id. There are global 715 and driver specific properties. Some values can be set differently 716 for input and output, they're marked with ``in|out.``. You can set 717 the input's property with ``in.prop`` and the output's property with 718 ``out.prop``. For example: 719 720 :: 721 722 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 723 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 724 725 NOTE: parameter validation is known to be incomplete, in many cases 726 specifying an invalid option causes QEMU to print an error message 727 and continue emulation without sound. 728 729 Valid global options are: 730 731 ``id=identifier`` 732 Identifies the audio backend. 733 734 ``timer-period=period`` 735 Sets the timer period used by the audio subsystem in 736 microseconds. Default is 10000 (10 ms). 737 738 ``in|out.mixing-engine=on|off`` 739 Use QEMU's mixing engine to mix all streams inside QEMU and 740 convert audio formats when not supported by the backend. When 741 off, fixed-settings must be off too. Note that disabling this 742 option means that the selected backend must support multiple 743 streams and the audio formats used by the virtual cards, 744 otherwise you'll get no sound. It's not recommended to disable 745 this option unless you want to use 5.1 or 7.1 audio, as mixing 746 engine only supports mono and stereo audio. Default is on. 747 748 ``in|out.fixed-settings=on|off`` 749 Use fixed settings for host audio. When off, it will change 750 based on how the guest opens the sound card. In this case you 751 must not specify frequency, channels or format. Default is on. 752 753 ``in|out.frequency=frequency`` 754 Specify the frequency to use when using fixed-settings. Default 755 is 44100Hz. 756 757 ``in|out.channels=channels`` 758 Specify the number of channels to use when using fixed-settings. 759 Default is 2 (stereo). 760 761 ``in|out.format=format`` 762 Specify the sample format to use when using fixed-settings. 763 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 764 ``u32``, ``f32``. Default is ``s16``. 765 766 ``in|out.voices=voices`` 767 Specify the number of voices to use. Default is 1. 768 769 ``in|out.buffer-length=usecs`` 770 Sets the size of the buffer in microseconds. 771 772``-audiodev none,id=id[,prop[=value][,...]]`` 773 Creates a dummy backend that discards all outputs. This backend has 774 no backend specific properties. 775 776``-audiodev alsa,id=id[,prop[=value][,...]]`` 777 Creates backend using the ALSA. This backend is only available on 778 Linux. 779 780 ALSA specific options are: 781 782 ``in|out.dev=device`` 783 Specify the ALSA device to use for input and/or output. Default 784 is ``default``. 785 786 ``in|out.period-length=usecs`` 787 Sets the period length in microseconds. 788 789 ``in|out.try-poll=on|off`` 790 Attempt to use poll mode with the device. Default is on. 791 792 ``threshold=threshold`` 793 Threshold (in microseconds) when playback starts. Default is 0. 794 795``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 796 Creates a backend using Apple's Core Audio. This backend is only 797 available on Mac OS and only supports playback. 798 799 Core Audio specific options are: 800 801 ``in|out.buffer-count=count`` 802 Sets the count of the buffers. 803 804``-audiodev dsound,id=id[,prop[=value][,...]]`` 805 Creates a backend using Microsoft's DirectSound. This backend is 806 only available on Windows and only supports playback. 807 808 DirectSound specific options are: 809 810 ``latency=usecs`` 811 Add extra usecs microseconds latency to playback. Default is 812 10000 (10 ms). 813 814``-audiodev oss,id=id[,prop[=value][,...]]`` 815 Creates a backend using OSS. This backend is available on most 816 Unix-like systems. 817 818 OSS specific options are: 819 820 ``in|out.dev=device`` 821 Specify the file name of the OSS device to use. Default is 822 ``/dev/dsp``. 823 824 ``in|out.buffer-count=count`` 825 Sets the count of the buffers. 826 827 ``in|out.try-poll=on|of`` 828 Attempt to use poll mode with the device. Default is on. 829 830 ``try-mmap=on|off`` 831 Try using memory mapped device access. Default is off. 832 833 ``exclusive=on|off`` 834 Open the device in exclusive mode (vmix won't work in this 835 case). Default is off. 836 837 ``dsp-policy=policy`` 838 Sets the timing policy (between 0 and 10, where smaller number 839 means smaller latency but higher CPU usage). Use -1 to use 840 buffer sizes specified by ``buffer`` and ``buffer-count``. This 841 option is ignored if you do not have OSS 4. Default is 5. 842 843``-audiodev pa,id=id[,prop[=value][,...]]`` 844 Creates a backend using PulseAudio. This backend is available on 845 most systems. 846 847 PulseAudio specific options are: 848 849 ``server=server`` 850 Sets the PulseAudio server to connect to. 851 852 ``in|out.name=sink`` 853 Use the specified source/sink for recording/playback. 854 855 ``in|out.latency=usecs`` 856 Desired latency in microseconds. The PulseAudio server will try 857 to honor this value but actual latencies may be lower or higher. 858 859``-audiodev sdl,id=id[,prop[=value][,...]]`` 860 Creates a backend using SDL. This backend is available on most 861 systems, but you should use your platform's native backend if 862 possible. 863 864 SDL specific options are: 865 866 ``in|out.buffer-count=count`` 867 Sets the count of the buffers. 868 869``-audiodev spice,id=id[,prop[=value][,...]]`` 870 Creates a backend that sends audio through SPICE. This backend 871 requires ``-spice`` and automatically selected in that case, so 872 usually you can ignore this option. This backend has no backend 873 specific properties. 874 875``-audiodev wav,id=id[,prop[=value][,...]]`` 876 Creates a backend that writes audio to a WAV file. 877 878 Backend specific options are: 879 880 ``path=path`` 881 Write recorded audio into the specified file. Default is 882 ``qemu.wav``. 883ERST 884 885DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 886 "-soundhw c1,... enable audio support\n" 887 " and only specified sound cards (comma separated list)\n" 888 " use '-soundhw help' to get the list of supported cards\n" 889 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 890SRST 891``-soundhw card1[,card2,...] or -soundhw all`` 892 Enable audio and selected sound hardware. Use 'help' to print all 893 available sound hardware. For example: 894 895 .. parsed-literal:: 896 897 |qemu_system_x86| -soundhw sb16,adlib disk.img 898 |qemu_system_x86| -soundhw es1370 disk.img 899 |qemu_system_x86| -soundhw ac97 disk.img 900 |qemu_system_x86| -soundhw hda disk.img 901 |qemu_system_x86| -soundhw all disk.img 902 |qemu_system_x86| -soundhw help 903 904 Note that Linux's i810\_audio OSS kernel (for AC97) module might 905 require manually specifying clocking. 906 907 :: 908 909 modprobe i810_audio clocking=48000 910ERST 911 912DEF("device", HAS_ARG, QEMU_OPTION_device, 913 "-device driver[,prop[=value][,...]]\n" 914 " add device (based on driver)\n" 915 " prop=value,... sets driver properties\n" 916 " use '-device help' to print all possible drivers\n" 917 " use '-device driver,help' to print all possible properties\n", 918 QEMU_ARCH_ALL) 919SRST 920``-device driver[,prop[=value][,...]]`` 921 Add device driver. prop=value sets driver properties. Valid 922 properties depend on the driver. To get help on possible drivers and 923 properties, use ``-device help`` and ``-device driver,help``. 924 925 Some drivers are: 926 927``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 928 Add an IPMI BMC. This is a simulation of a hardware management 929 interface processor that normally sits on a system. It provides a 930 watchdog and the ability to reset and power control the system. You 931 need to connect this to an IPMI interface to make it useful 932 933 The IPMI slave address to use for the BMC. The default is 0x20. This 934 address is the BMC's address on the I2C network of management 935 controllers. If you don't know what this means, it is safe to ignore 936 it. 937 938 ``id=id`` 939 The BMC id for interfaces to use this device. 940 941 ``slave_addr=val`` 942 Define slave address to use for the BMC. The default is 0x20. 943 944 ``sdrfile=file`` 945 file containing raw Sensor Data Records (SDR) data. The default 946 is none. 947 948 ``fruareasize=val`` 949 size of a Field Replaceable Unit (FRU) area. The default is 950 1024. 951 952 ``frudatafile=file`` 953 file containing raw Field Replaceable Unit (FRU) inventory data. 954 The default is none. 955 956 ``guid=uuid`` 957 value for the GUID for the BMC, in standard UUID format. If this 958 is set, get "Get GUID" command to the BMC will return it. 959 Otherwise "Get GUID" will return an error. 960 961``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 962 Add a connection to an external IPMI BMC simulator. Instead of 963 locally emulating the BMC like the above item, instead connect to an 964 external entity that provides the IPMI services. 965 966 A connection is made to an external BMC simulator. If you do this, 967 it is strongly recommended that you use the "reconnect=" chardev 968 option to reconnect to the simulator if the connection is lost. Note 969 that if this is not used carefully, it can be a security issue, as 970 the interface has the ability to send resets, NMIs, and power off 971 the VM. It's best if QEMU makes a connection to an external 972 simulator running on a secure port on localhost, so neither the 973 simulator nor QEMU is exposed to any outside network. 974 975 See the "lanserv/README.vm" file in the OpenIPMI library for more 976 details on the external interface. 977 978``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 979 Add a KCS IPMI interafce on the ISA bus. This also adds a 980 corresponding ACPI and SMBIOS entries, if appropriate. 981 982 ``bmc=id`` 983 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 984 above. 985 986 ``ioport=val`` 987 Define the I/O address of the interface. The default is 0xca0 988 for KCS. 989 990 ``irq=val`` 991 Define the interrupt to use. The default is 5. To disable 992 interrupts, set this to 0. 993 994``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 995 Like the KCS interface, but defines a BT interface. The default port 996 is 0xe4 and the default interrupt is 5. 997 998``-device pci-ipmi-kcs,bmc=id`` 999 Add a KCS IPMI interafce on the PCI bus. 1000 1001 ``bmc=id`` 1002 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1003 1004``-device pci-ipmi-bt,bmc=id`` 1005 Like the KCS interface, but defines a BT interface on the PCI bus. 1006 1007``-device intel-iommu[,option=...]`` 1008 This is only supported by ``-machine q35``, which will enable Intel VT-d 1009 emulation within the guest. It supports below options: 1010 1011 ``intremap=on|off`` (default: auto) 1012 This enables interrupt remapping feature. It's required to enable 1013 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1014 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1015 The default value is "auto", which will be decided by the mode of 1016 kernel-irqchip. 1017 1018 ``caching-mode=on|off`` (default: off) 1019 This enables caching mode for the VT-d emulated device. When 1020 caching-mode is enabled, each guest DMA buffer mapping will generate an 1021 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1022 a synchronous way. It is required for ``-device vfio-pci`` to work 1023 with the VT-d device, because host assigned devices requires to setup 1024 the DMA mapping on the host before guest DMA starts. 1025 1026 ``device-iotlb=on|off`` (default: off) 1027 This enables device-iotlb capability for the emulated VT-d device. So 1028 far virtio/vhost should be the only real user for this parameter, 1029 paired with ats=on configured for the device. 1030 1031 ``aw-bits=39|48`` (default: 39) 1032 This decides the address width of IOVA address space. The address 1033 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1034 4-level IOMMU page tables. 1035 1036 Please also refer to the wiki page for general scenarios of VT-d 1037 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1038 1039ERST 1040 1041DEF("name", HAS_ARG, QEMU_OPTION_name, 1042 "-name string1[,process=string2][,debug-threads=on|off]\n" 1043 " set the name of the guest\n" 1044 " string1 sets the window title and string2 the process name\n" 1045 " When debug-threads is enabled, individual threads are given a separate name\n" 1046 " NOTE: The thread names are for debugging and not a stable API.\n", 1047 QEMU_ARCH_ALL) 1048SRST 1049``-name name`` 1050 Sets the name of the guest. This name will be displayed in the SDL 1051 window caption. The name will also be used for the VNC server. Also 1052 optionally set the top visible process name in Linux. Naming of 1053 individual threads can also be enabled on Linux to aid debugging. 1054ERST 1055 1056DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1057 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1058 " specify machine UUID\n", QEMU_ARCH_ALL) 1059SRST 1060``-uuid uuid`` 1061 Set system UUID. 1062ERST 1063 1064DEFHEADING() 1065 1066DEFHEADING(Block device options:) 1067 1068DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1069 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1070DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1071SRST 1072``-fda file`` 1073 \ 1074``-fdb file`` 1075 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1076 the System Emulation Users Guide). 1077ERST 1078 1079DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1080 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1081DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1082DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1083 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1084DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1085SRST 1086``-hda file`` 1087 \ 1088``-hdb file`` 1089 \ 1090``-hdc file`` 1091 \ 1092``-hdd file`` 1093 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1094 chapter in the System Emulation Users Guide). 1095ERST 1096 1097DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1098 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1099 QEMU_ARCH_ALL) 1100SRST 1101``-cdrom file`` 1102 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1103 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1104 as filename. 1105ERST 1106 1107DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1108 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1109 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1110 " [,read-only=on|off][,auto-read-only=on|off]\n" 1111 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1112 " [,driver specific parameters...]\n" 1113 " configure a block backend\n", QEMU_ARCH_ALL) 1114SRST 1115``-blockdev option[,option[,option[,...]]]`` 1116 Define a new block driver node. Some of the options apply to all 1117 block drivers, other options are only accepted for a specific block 1118 driver. See below for a list of generic options and options for the 1119 most common block drivers. 1120 1121 Options that expect a reference to another node (e.g. ``file``) can 1122 be given in two ways. Either you specify the node name of an already 1123 existing node (file=node-name), or you define a new node inline, 1124 adding options for the referenced node after a dot 1125 (file.filename=path,file.aio=native). 1126 1127 A block driver node created with ``-blockdev`` can be used for a 1128 guest device by specifying its node name for the ``drive`` property 1129 in a ``-device`` argument that defines a block device. 1130 1131 ``Valid options for any block driver node:`` 1132 ``driver`` 1133 Specifies the block driver to use for the given node. 1134 1135 ``node-name`` 1136 This defines the name of the block driver node by which it 1137 will be referenced later. The name must be unique, i.e. it 1138 must not match the name of a different block driver node, or 1139 (if you use ``-drive`` as well) the ID of a drive. 1140 1141 If no node name is specified, it is automatically generated. 1142 The generated node name is not intended to be predictable 1143 and changes between QEMU invocations. For the top level, an 1144 explicit node name must be specified. 1145 1146 ``read-only`` 1147 Open the node read-only. Guest write attempts will fail. 1148 1149 Note that some block drivers support only read-only access, 1150 either generally or in certain configurations. In this case, 1151 the default value ``read-only=off`` does not work and the 1152 option must be specified explicitly. 1153 1154 ``auto-read-only`` 1155 If ``auto-read-only=on`` is set, QEMU may fall back to 1156 read-only usage even when ``read-only=off`` is requested, or 1157 even switch between modes as needed, e.g. depending on 1158 whether the image file is writable or whether a writing user 1159 is attached to the node. 1160 1161 ``force-share`` 1162 Override the image locking system of QEMU by forcing the 1163 node to utilize weaker shared access for permissions where 1164 it would normally request exclusive access. When there is 1165 the potential for multiple instances to have the same file 1166 open (whether this invocation of QEMU is the first or the 1167 second instance), both instances must permit shared access 1168 for the second instance to succeed at opening the file. 1169 1170 Enabling ``force-share=on`` requires ``read-only=on``. 1171 1172 ``cache.direct`` 1173 The host page cache can be avoided with ``cache.direct=on``. 1174 This will attempt to do disk IO directly to the guest's 1175 memory. QEMU may still perform an internal copy of the data. 1176 1177 ``cache.no-flush`` 1178 In case you don't care about data integrity over host 1179 failures, you can use ``cache.no-flush=on``. This option 1180 tells QEMU that it never needs to write any data to the disk 1181 but can instead keep things in cache. If anything goes 1182 wrong, like your host losing power, the disk storage getting 1183 disconnected accidentally, etc. your image will most 1184 probably be rendered unusable. 1185 1186 ``discard=discard`` 1187 discard is one of "ignore" (or "off") or "unmap" (or "on") 1188 and controls whether ``discard`` (also known as ``trim`` or 1189 ``unmap``) requests are ignored or passed to the filesystem. 1190 Some machine types may not support discard requests. 1191 1192 ``detect-zeroes=detect-zeroes`` 1193 detect-zeroes is "off", "on" or "unmap" and enables the 1194 automatic conversion of plain zero writes by the OS to 1195 driver specific optimized zero write commands. You may even 1196 choose "unmap" if discard is set to "unmap" to allow a zero 1197 write to be converted to an ``unmap`` operation. 1198 1199 ``Driver-specific options for file`` 1200 This is the protocol-level block driver for accessing regular 1201 files. 1202 1203 ``filename`` 1204 The path to the image file in the local filesystem 1205 1206 ``aio`` 1207 Specifies the AIO backend (threads/native/io_uring, 1208 default: threads) 1209 1210 ``locking`` 1211 Specifies whether the image file is protected with Linux OFD 1212 / POSIX locks. The default is to use the Linux Open File 1213 Descriptor API if available, otherwise no lock is applied. 1214 (auto/on/off, default: auto) 1215 1216 Example: 1217 1218 :: 1219 1220 -blockdev driver=file,node-name=disk,filename=disk.img 1221 1222 ``Driver-specific options for raw`` 1223 This is the image format block driver for raw images. It is 1224 usually stacked on top of a protocol level block driver such as 1225 ``file``. 1226 1227 ``file`` 1228 Reference to or definition of the data source block driver 1229 node (e.g. a ``file`` driver node) 1230 1231 Example 1: 1232 1233 :: 1234 1235 -blockdev driver=file,node-name=disk_file,filename=disk.img 1236 -blockdev driver=raw,node-name=disk,file=disk_file 1237 1238 Example 2: 1239 1240 :: 1241 1242 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1243 1244 ``Driver-specific options for qcow2`` 1245 This is the image format block driver for qcow2 images. It is 1246 usually stacked on top of a protocol level block driver such as 1247 ``file``. 1248 1249 ``file`` 1250 Reference to or definition of the data source block driver 1251 node (e.g. a ``file`` driver node) 1252 1253 ``backing`` 1254 Reference to or definition of the backing file block device 1255 (default is taken from the image file). It is allowed to 1256 pass ``null`` here in order to disable the default backing 1257 file. 1258 1259 ``lazy-refcounts`` 1260 Whether to enable the lazy refcounts feature (on/off; 1261 default is taken from the image file) 1262 1263 ``cache-size`` 1264 The maximum total size of the L2 table and refcount block 1265 caches in bytes (default: the sum of l2-cache-size and 1266 refcount-cache-size) 1267 1268 ``l2-cache-size`` 1269 The maximum size of the L2 table cache in bytes (default: if 1270 cache-size is not specified - 32M on Linux platforms, and 8M 1271 on non-Linux platforms; otherwise, as large as possible 1272 within the cache-size, while permitting the requested or the 1273 minimal refcount cache size) 1274 1275 ``refcount-cache-size`` 1276 The maximum size of the refcount block cache in bytes 1277 (default: 4 times the cluster size; or if cache-size is 1278 specified, the part of it which is not used for the L2 1279 cache) 1280 1281 ``cache-clean-interval`` 1282 Clean unused entries in the L2 and refcount caches. The 1283 interval is in seconds. The default value is 600 on 1284 supporting platforms, and 0 on other platforms. Setting it 1285 to 0 disables this feature. 1286 1287 ``pass-discard-request`` 1288 Whether discard requests to the qcow2 device should be 1289 forwarded to the data source (on/off; default: on if 1290 discard=unmap is specified, off otherwise) 1291 1292 ``pass-discard-snapshot`` 1293 Whether discard requests for the data source should be 1294 issued when a snapshot operation (e.g. deleting a snapshot) 1295 frees clusters in the qcow2 file (on/off; default: on) 1296 1297 ``pass-discard-other`` 1298 Whether discard requests for the data source should be 1299 issued on other occasions where a cluster gets freed 1300 (on/off; default: off) 1301 1302 ``overlap-check`` 1303 Which overlap checks to perform for writes to the image 1304 (none/constant/cached/all; default: cached). For details or 1305 finer granularity control refer to the QAPI documentation of 1306 ``blockdev-add``. 1307 1308 Example 1: 1309 1310 :: 1311 1312 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1313 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1314 1315 Example 2: 1316 1317 :: 1318 1319 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1320 1321 ``Driver-specific options for other drivers`` 1322 Please refer to the QAPI documentation of the ``blockdev-add`` 1323 QMP command. 1324ERST 1325 1326DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1327 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1328 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1329 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1330 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1331 " [,aio=threads|native|io_uring]\n" 1332 " [,readonly=on|off][,copy-on-read=on|off]\n" 1333 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1334 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1335 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1336 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1337 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1338 " [[,iops_size=is]]\n" 1339 " [[,group=g]]\n" 1340 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1341SRST 1342``-drive option[,option[,option[,...]]]`` 1343 Define a new drive. This includes creating a block driver node (the 1344 backend) as well as a guest device, and is mostly a shortcut for 1345 defining the corresponding ``-blockdev`` and ``-device`` options. 1346 1347 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1348 In addition, it knows the following options: 1349 1350 ``file=file`` 1351 This option defines which disk image (see the :ref:`disk images` 1352 chapter in the System Emulation Users Guide) to use with this drive. 1353 If the filename contains comma, you must double it (for instance, 1354 "file=my,,file" to use file "my,file"). 1355 1356 Special files such as iSCSI devices can be specified using 1357 protocol specific URLs. See the section for "Device URL Syntax" 1358 for more information. 1359 1360 ``if=interface`` 1361 This option defines on which type on interface the drive is 1362 connected. Available types are: ide, scsi, sd, mtd, floppy, 1363 pflash, virtio, none. 1364 1365 ``bus=bus,unit=unit`` 1366 These options define where is connected the drive by defining 1367 the bus number and the unit id. 1368 1369 ``index=index`` 1370 This option defines where is connected the drive by using an 1371 index in the list of available connectors of a given interface 1372 type. 1373 1374 ``media=media`` 1375 This option defines the type of the media: disk or cdrom. 1376 1377 ``snapshot=snapshot`` 1378 snapshot is "on" or "off" and controls snapshot mode for the 1379 given drive (see ``-snapshot``). 1380 1381 ``cache=cache`` 1382 cache is "none", "writeback", "unsafe", "directsync" or 1383 "writethrough" and controls how the host cache is used to access 1384 block data. This is a shortcut that sets the ``cache.direct`` 1385 and ``cache.no-flush`` options (as in ``-blockdev``), and 1386 additionally ``cache.writeback``, which provides a default for 1387 the ``write-cache`` option of block guest devices (as in 1388 ``-device``). The modes correspond to the following settings: 1389 1390 ============= =============== ============ ============== 1391 \ cache.writeback cache.direct cache.no-flush 1392 ============= =============== ============ ============== 1393 writeback on off off 1394 none on on off 1395 writethrough off off off 1396 directsync off on off 1397 unsafe on off on 1398 ============= =============== ============ ============== 1399 1400 The default mode is ``cache=writeback``. 1401 1402 ``aio=aio`` 1403 aio is "threads", "native", or "io_uring" and selects between pthread 1404 based disk I/O, native Linux AIO, or Linux io_uring API. 1405 1406 ``format=format`` 1407 Specify which disk format will be used rather than detecting the 1408 format. Can be used to specify format=raw to avoid interpreting 1409 an untrusted format header. 1410 1411 ``werror=action,rerror=action`` 1412 Specify which action to take on write and read errors. Valid 1413 actions are: "ignore" (ignore the error and try to continue), 1414 "stop" (pause QEMU), "report" (report the error to the guest), 1415 "enospc" (pause QEMU only if the host disk is full; report the 1416 error to the guest otherwise). The default setting is 1417 ``werror=enospc`` and ``rerror=report``. 1418 1419 ``copy-on-read=copy-on-read`` 1420 copy-on-read is "on" or "off" and enables whether to copy read 1421 backing file sectors into the image file. 1422 1423 ``bps=b,bps_rd=r,bps_wr=w`` 1424 Specify bandwidth throttling limits in bytes per second, either 1425 for all request types or for reads or writes only. Small values 1426 can lead to timeouts or hangs inside the guest. A safe minimum 1427 for disks is 2 MB/s. 1428 1429 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1430 Specify bursts in bytes per second, either for all request types 1431 or for reads or writes only. Bursts allow the guest I/O to spike 1432 above the limit temporarily. 1433 1434 ``iops=i,iops_rd=r,iops_wr=w`` 1435 Specify request rate limits in requests per second, either for 1436 all request types or for reads or writes only. 1437 1438 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1439 Specify bursts in requests per second, either for all request 1440 types or for reads or writes only. Bursts allow the guest I/O to 1441 spike above the limit temporarily. 1442 1443 ``iops_size=is`` 1444 Let every is bytes of a request count as a new request for iops 1445 throttling purposes. Use this option to prevent guests from 1446 circumventing iops limits by sending fewer but larger requests. 1447 1448 ``group=g`` 1449 Join a throttling quota group with given name g. All drives that 1450 are members of the same group are accounted for together. Use 1451 this option to prevent guests from circumventing throttling 1452 limits by using many small disks instead of a single larger 1453 disk. 1454 1455 By default, the ``cache.writeback=on`` mode is used. It will report 1456 data writes as completed as soon as the data is present in the host 1457 page cache. This is safe as long as your guest OS makes sure to 1458 correctly flush disk caches where needed. If your guest OS does not 1459 handle volatile disk write caches correctly and your host crashes or 1460 loses power, then the guest may experience data corruption. 1461 1462 For such guests, you should consider using ``cache.writeback=off``. 1463 This means that the host page cache will be used to read and write 1464 data, but write notification will be sent to the guest only after 1465 QEMU has made sure to flush each write to the disk. Be aware that 1466 this has a major impact on performance. 1467 1468 When using the ``-snapshot`` option, unsafe caching is always used. 1469 1470 Copy-on-read avoids accessing the same backing file sectors 1471 repeatedly and is useful when the backing file is over a slow 1472 network. By default copy-on-read is off. 1473 1474 Instead of ``-cdrom`` you can use: 1475 1476 .. parsed-literal:: 1477 1478 |qemu_system| -drive file=file,index=2,media=cdrom 1479 1480 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1481 1482 .. parsed-literal:: 1483 1484 |qemu_system| -drive file=file,index=0,media=disk 1485 |qemu_system| -drive file=file,index=1,media=disk 1486 |qemu_system| -drive file=file,index=2,media=disk 1487 |qemu_system| -drive file=file,index=3,media=disk 1488 1489 You can open an image using pre-opened file descriptors from an fd 1490 set: 1491 1492 .. parsed-literal:: 1493 1494 |qemu_system| \\ 1495 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1496 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1497 -drive file=/dev/fdset/2,index=0,media=disk 1498 1499 You can connect a CDROM to the slave of ide0: 1500 1501 .. parsed-literal:: 1502 1503 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1504 1505 If you don't specify the "file=" argument, you define an empty 1506 drive: 1507 1508 .. parsed-literal:: 1509 1510 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1511 1512 Instead of ``-fda``, ``-fdb``, you can use: 1513 1514 .. parsed-literal:: 1515 1516 |qemu_system_x86| -drive file=file,index=0,if=floppy 1517 |qemu_system_x86| -drive file=file,index=1,if=floppy 1518 1519 By default, interface is "ide" and index is automatically 1520 incremented: 1521 1522 .. parsed-literal:: 1523 1524 |qemu_system_x86| -drive file=a -drive file=b" 1525 1526 is interpreted like: 1527 1528 .. parsed-literal:: 1529 1530 |qemu_system_x86| -hda a -hdb b 1531ERST 1532 1533DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1534 "-mtdblock file use 'file' as on-board Flash memory image\n", 1535 QEMU_ARCH_ALL) 1536SRST 1537``-mtdblock file`` 1538 Use file as on-board Flash memory image. 1539ERST 1540 1541DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1542 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1543SRST 1544``-sd file`` 1545 Use file as SecureDigital card image. 1546ERST 1547 1548DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1549 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1550SRST 1551``-pflash file`` 1552 Use file as a parallel flash image. 1553ERST 1554 1555DEF("snapshot", 0, QEMU_OPTION_snapshot, 1556 "-snapshot write to temporary files instead of disk image files\n", 1557 QEMU_ARCH_ALL) 1558SRST 1559``-snapshot`` 1560 Write to temporary files instead of disk image files. In this case, 1561 the raw disk image you use is not written back. You can however 1562 force the write back by pressing C-a s (see the :ref:`disk images` 1563 chapter in the System Emulation Users Guide). 1564ERST 1565 1566DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1567 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1568 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1569 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1570 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1571 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1572 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1573 " [[,throttling.iops-size=is]]\n" 1574 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1575 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1576 "-fsdev synth,id=id\n", 1577 QEMU_ARCH_ALL) 1578 1579SRST 1580``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1581 \ 1582``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1583 \ 1584``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1585 \ 1586``-fsdev synth,id=id[,readonly=on]`` 1587 Define a new file system device. Valid options are: 1588 1589 ``local`` 1590 Accesses to the filesystem are done by QEMU. 1591 1592 ``proxy`` 1593 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1594 1595 ``synth`` 1596 Synthetic filesystem, only used by QTests. 1597 1598 ``id=id`` 1599 Specifies identifier for this device. 1600 1601 ``path=path`` 1602 Specifies the export path for the file system device. Files 1603 under this path will be available to the 9p client on the guest. 1604 1605 ``security_model=security_model`` 1606 Specifies the security model to be used for this export path. 1607 Supported security models are "passthrough", "mapped-xattr", 1608 "mapped-file" and "none". In "passthrough" security model, files 1609 are stored using the same credentials as they are created on the 1610 guest. This requires QEMU to run as root. In "mapped-xattr" 1611 security model, some of the file attributes like uid, gid, mode 1612 bits and link target are stored as file attributes. For 1613 "mapped-file" these attributes are stored in the hidden 1614 .virtfs\_metadata directory. Directories exported by this 1615 security model cannot interact with other unix tools. "none" 1616 security model is same as passthrough except the sever won't 1617 report failures if it fails to set file attributes like 1618 ownership. Security model is mandatory only for local fsdriver. 1619 Other fsdrivers (like proxy) don't take security model as a 1620 parameter. 1621 1622 ``writeout=writeout`` 1623 This is an optional argument. The only supported value is 1624 "immediate". This means that host page cache will be used to 1625 read and write data but write notification will be sent to the 1626 guest only when the data has been reported as written by the 1627 storage subsystem. 1628 1629 ``readonly=on`` 1630 Enables exporting 9p share as a readonly mount for guests. By 1631 default read-write access is given. 1632 1633 ``socket=socket`` 1634 Enables proxy filesystem driver to use passed socket file for 1635 communicating with virtfs-proxy-helper(1). 1636 1637 ``sock_fd=sock_fd`` 1638 Enables proxy filesystem driver to use passed socket descriptor 1639 for communicating with virtfs-proxy-helper(1). Usually a helper 1640 like libvirt will create socketpair and pass one of the fds as 1641 sock\_fd. 1642 1643 ``fmode=fmode`` 1644 Specifies the default mode for newly created files on the host. 1645 Works only with security models "mapped-xattr" and 1646 "mapped-file". 1647 1648 ``dmode=dmode`` 1649 Specifies the default mode for newly created directories on the 1650 host. Works only with security models "mapped-xattr" and 1651 "mapped-file". 1652 1653 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1654 Specify bandwidth throttling limits in bytes per second, either 1655 for all request types or for reads or writes only. 1656 1657 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1658 Specify bursts in bytes per second, either for all request types 1659 or for reads or writes only. Bursts allow the guest I/O to spike 1660 above the limit temporarily. 1661 1662 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1663 Specify request rate limits in requests per second, either for 1664 all request types or for reads or writes only. 1665 1666 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1667 Specify bursts in requests per second, either for all request 1668 types or for reads or writes only. Bursts allow the guest I/O to 1669 spike above the limit temporarily. 1670 1671 ``throttling.iops-size=is`` 1672 Let every is bytes of a request count as a new request for iops 1673 throttling purposes. 1674 1675 -fsdev option is used along with -device driver "virtio-9p-...". 1676 1677``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1678 Options for virtio-9p-... driver are: 1679 1680 ``type`` 1681 Specifies the variant to be used. Supported values are "pci", 1682 "ccw" or "device", depending on the machine type. 1683 1684 ``fsdev=id`` 1685 Specifies the id value specified along with -fsdev option. 1686 1687 ``mount_tag=mount_tag`` 1688 Specifies the tag name to be used by the guest to mount this 1689 export point. 1690ERST 1691 1692DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1693 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1694 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1695 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1696 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1697 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1698 QEMU_ARCH_ALL) 1699 1700SRST 1701``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1702 \ 1703``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1704 \ 1705``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1706 \ 1707``-virtfs synth,mount_tag=mount_tag`` 1708 Define a new virtual filesystem device and expose it to the guest using 1709 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1710 directory on host is made directly accessible by guest as a pass-through 1711 file system by using the 9P network protocol for communication between 1712 host and guests, if desired even accessible, shared by several guests 1713 simultaniously. 1714 1715 Note that ``-virtfs`` is actually just a convenience shortcut for its 1716 generalized form ``-fsdev -device virtio-9p-pci``. 1717 1718 The general form of pass-through file system options are: 1719 1720 ``local`` 1721 Accesses to the filesystem are done by QEMU. 1722 1723 ``proxy`` 1724 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1725 1726 ``synth`` 1727 Synthetic filesystem, only used by QTests. 1728 1729 ``id=id`` 1730 Specifies identifier for the filesystem device 1731 1732 ``path=path`` 1733 Specifies the export path for the file system device. Files 1734 under this path will be available to the 9p client on the guest. 1735 1736 ``security_model=security_model`` 1737 Specifies the security model to be used for this export path. 1738 Supported security models are "passthrough", "mapped-xattr", 1739 "mapped-file" and "none". In "passthrough" security model, files 1740 are stored using the same credentials as they are created on the 1741 guest. This requires QEMU to run as root. In "mapped-xattr" 1742 security model, some of the file attributes like uid, gid, mode 1743 bits and link target are stored as file attributes. For 1744 "mapped-file" these attributes are stored in the hidden 1745 .virtfs\_metadata directory. Directories exported by this 1746 security model cannot interact with other unix tools. "none" 1747 security model is same as passthrough except the sever won't 1748 report failures if it fails to set file attributes like 1749 ownership. Security model is mandatory only for local fsdriver. 1750 Other fsdrivers (like proxy) don't take security model as a 1751 parameter. 1752 1753 ``writeout=writeout`` 1754 This is an optional argument. The only supported value is 1755 "immediate". This means that host page cache will be used to 1756 read and write data but write notification will be sent to the 1757 guest only when the data has been reported as written by the 1758 storage subsystem. 1759 1760 ``readonly=on`` 1761 Enables exporting 9p share as a readonly mount for guests. By 1762 default read-write access is given. 1763 1764 ``socket=socket`` 1765 Enables proxy filesystem driver to use passed socket file for 1766 communicating with virtfs-proxy-helper(1). Usually a helper like 1767 libvirt will create socketpair and pass one of the fds as 1768 sock\_fd. 1769 1770 ``sock_fd`` 1771 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1772 socket descriptor for interfacing with virtfs-proxy-helper(1). 1773 1774 ``fmode=fmode`` 1775 Specifies the default mode for newly created files on the host. 1776 Works only with security models "mapped-xattr" and 1777 "mapped-file". 1778 1779 ``dmode=dmode`` 1780 Specifies the default mode for newly created directories on the 1781 host. Works only with security models "mapped-xattr" and 1782 "mapped-file". 1783 1784 ``mount_tag=mount_tag`` 1785 Specifies the tag name to be used by the guest to mount this 1786 export point. 1787 1788 ``multidevs=multidevs`` 1789 Specifies how to deal with multiple devices being shared with a 1790 9p export. Supported behaviours are either "remap", "forbid" or 1791 "warn". The latter is the default behaviour on which virtfs 9p 1792 expects only one device to be shared with the same export, and 1793 if more than one device is shared and accessed via the same 9p 1794 export then only a warning message is logged (once) by qemu on 1795 host side. In order to avoid file ID collisions on guest you 1796 should either create a separate virtfs export for each device to 1797 be shared with guests (recommended way) or you might use "remap" 1798 instead which allows you to share multiple devices with only one 1799 export instead, which is achieved by remapping the original 1800 inode numbers from host to guest in a way that would prevent 1801 such collisions. Remapping inodes in such use cases is required 1802 because the original device IDs from host are never passed and 1803 exposed on guest. Instead all files of an export shared with 1804 virtfs always share the same device id on guest. So two files 1805 with identical inode numbers but from actually different devices 1806 on host would otherwise cause a file ID collision and hence 1807 potential misbehaviours on guest. "forbid" on the other hand 1808 assumes like "warn" that only one device is shared by the same 1809 export, however it will not only log a warning message but also 1810 deny access to additional devices on guest. Note though that 1811 "forbid" does currently not block all possible file access 1812 operations (e.g. readdir() would still return entries from other 1813 devices). 1814ERST 1815 1816DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1817 "-iscsi [user=user][,password=password]\n" 1818 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1819 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1820 " [,timeout=timeout]\n" 1821 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1822 1823SRST 1824``-iscsi`` 1825 Configure iSCSI session parameters. 1826ERST 1827 1828DEFHEADING() 1829 1830DEFHEADING(USB convenience options:) 1831 1832DEF("usb", 0, QEMU_OPTION_usb, 1833 "-usb enable on-board USB host controller (if not enabled by default)\n", 1834 QEMU_ARCH_ALL) 1835SRST 1836``-usb`` 1837 Enable USB emulation on machine types with an on-board USB host 1838 controller (if not enabled by default). Note that on-board USB host 1839 controllers may not support USB 3.0. In this case 1840 ``-device qemu-xhci`` can be used instead on machines with PCI. 1841ERST 1842 1843DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1844 "-usbdevice name add the host or guest USB device 'name'\n", 1845 QEMU_ARCH_ALL) 1846SRST 1847``-usbdevice devname`` 1848 Add the USB device devname, and enable an on-board USB controller 1849 if possible and necessary (just like it can be done via 1850 ``-machine usb=on``). Note that this option is mainly intended for 1851 the user's convenience only. More fine-grained control can be 1852 achieved by selecting a USB host controller (if necessary) and the 1853 desired USB device via the ``-device`` option instead. For example, 1854 instead of using ``-usbdevice mouse`` it is possible to use 1855 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1856 to a USB 3.0 controller instead (at least on machines that support 1857 PCI and do not have an USB controller enabled by default yet). 1858 For more details, see the chapter about 1859 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1860 Possible devices for devname are: 1861 1862 ``braille`` 1863 Braille device. This will use BrlAPI to display the braille 1864 output on a real or fake device (i.e. it also creates a 1865 corresponding ``braille`` chardev automatically beside the 1866 ``usb-braille`` USB device). 1867 1868 ``keyboard`` 1869 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1870 1871 ``mouse`` 1872 Virtual Mouse. This will override the PS/2 mouse emulation when 1873 activated. 1874 1875 ``tablet`` 1876 Pointer device that uses absolute coordinates (like a 1877 touchscreen). This means QEMU is able to report the mouse 1878 position without having to grab the mouse. Also overrides the 1879 PS/2 mouse emulation when activated. 1880 1881 ``wacom-tablet`` 1882 Wacom PenPartner USB tablet. 1883 1884 1885ERST 1886 1887DEFHEADING() 1888 1889DEFHEADING(Display options:) 1890 1891DEF("display", HAS_ARG, QEMU_OPTION_display, 1892#if defined(CONFIG_SPICE) 1893 "-display spice-app[,gl=on|off]\n" 1894#endif 1895#if defined(CONFIG_SDL) 1896 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1897 " [,grab-mod=<mod>][,show-cursor=on|off][,window-close=on|off]\n" 1898#endif 1899#if defined(CONFIG_GTK) 1900 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1901 " [,show-cursor=on|off][,window-close=on|off]\n" 1902#endif 1903#if defined(CONFIG_VNC) 1904 "-display vnc=<display>[,<optargs>]\n" 1905#endif 1906#if defined(CONFIG_CURSES) 1907 "-display curses[,charset=<encoding>]\n" 1908#endif 1909#if defined(CONFIG_OPENGL) 1910 "-display egl-headless[,rendernode=<file>]\n" 1911#endif 1912#if defined(CONFIG_DBUS_DISPLAY) 1913 "-display dbus[,addr=<dbusaddr>]\n" 1914 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1915#endif 1916 "-display none\n" 1917 " select display backend type\n" 1918 " The default display is equivalent to\n " 1919#if defined(CONFIG_GTK) 1920 "\"-display gtk\"\n" 1921#elif defined(CONFIG_SDL) 1922 "\"-display sdl\"\n" 1923#elif defined(CONFIG_COCOA) 1924 "\"-display cocoa\"\n" 1925#elif defined(CONFIG_VNC) 1926 "\"-vnc localhost:0,to=99,id=default\"\n" 1927#else 1928 "\"-display none\"\n" 1929#endif 1930 , QEMU_ARCH_ALL) 1931SRST 1932``-display type`` 1933 Select type of display to use. This option is a replacement for the 1934 old style -sdl/-curses/... options. Use ``-display help`` to list 1935 the available display types. Valid values for type are 1936 1937 ``spice-app[,gl=on|off]`` 1938 Start QEMU as a Spice server and launch the default Spice client 1939 application. The Spice server will redirect the serial consoles 1940 and QEMU monitors. (Since 4.0) 1941 1942 ``dbus`` 1943 Export the display over D-Bus interfaces. (Since 7.0) 1944 1945 The connection is registered with the "org.qemu" name (and queued when 1946 already owned). 1947 1948 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 1949 1950 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 1951 1952 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 1953 will share framebuffers with DMABUF file descriptors). 1954 1955 ``sdl`` 1956 Display video output via SDL (usually in a separate graphics 1957 window; see the SDL documentation for other possibilities). 1958 Valid parameters are: 1959 1960 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 1961 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 1962 either ``lshift-lctrl-lalt`` or ``rctrl``. 1963 1964 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing. 1965 This parameter is deprecated - use ``grab-mod`` instead. 1966 1967 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing. 1968 This parameter is deprecated - use ``grab-mod`` instead. 1969 1970 ``gl=on|off|core|es`` : Use OpenGL for displaying 1971 1972 ``show-cursor=on|off`` : Force showing the mouse cursor 1973 1974 ``window-close=on|off`` : Allow to quit qemu with window close button 1975 1976 ``gtk`` 1977 Display video output in a GTK window. This interface provides 1978 drop-down menus and other UI elements to configure and control 1979 the VM during runtime. Valid parameters are: 1980 1981 ``full-screen=on|off`` : Start in fullscreen mode 1982 1983 ``gl=on|off`` : Use OpenGL for displaying 1984 1985 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 1986 1987 ``show-cursor=on|off`` : Force showing the mouse cursor 1988 1989 ``window-close=on|off`` : Allow to quit qemu with window close button 1990 1991 ``curses[,charset=<encoding>]`` 1992 Display video output via curses. For graphics device models 1993 which support a text mode, QEMU can display this output using a 1994 curses/ncurses interface. Nothing is displayed when the graphics 1995 device is in graphical mode or if the graphics device does not 1996 support a text mode. Generally only the VGA device models 1997 support text mode. The font charset used by the guest can be 1998 specified with the ``charset`` option, for example 1999 ``charset=CP850`` for IBM CP850 encoding. The default is 2000 ``CP437``. 2001 2002 ``egl-headless[,rendernode=<file>]`` 2003 Offload all OpenGL operations to a local DRI device. For any 2004 graphical display, this display needs to be paired with either 2005 VNC or SPICE displays. 2006 2007 ``vnc=<display>`` 2008 Start a VNC server on display <display> 2009 2010 ``none`` 2011 Do not display video output. The guest will still see an 2012 emulated graphics card, but its output will not be displayed to 2013 the QEMU user. This option differs from the -nographic option in 2014 that it only affects what is done with video output; -nographic 2015 also changes the destination of the serial and parallel port 2016 data. 2017ERST 2018 2019DEF("nographic", 0, QEMU_OPTION_nographic, 2020 "-nographic disable graphical output and redirect serial I/Os to console\n", 2021 QEMU_ARCH_ALL) 2022SRST 2023``-nographic`` 2024 Normally, if QEMU is compiled with graphical window support, it 2025 displays output such as guest graphics, guest console, and the QEMU 2026 monitor in a window. With this option, you can totally disable 2027 graphical output so that QEMU is a simple command line application. 2028 The emulated serial port is redirected on the console and muxed with 2029 the monitor (unless redirected elsewhere explicitly). Therefore, you 2030 can still use QEMU to debug a Linux kernel with a serial console. 2031 Use C-a h for help on switching between the console and monitor. 2032ERST 2033 2034DEF("curses", 0, QEMU_OPTION_curses, 2035 "-curses shorthand for -display curses\n", 2036 QEMU_ARCH_ALL) 2037SRST 2038``-curses`` 2039 Normally, if QEMU is compiled with graphical window support, it 2040 displays output such as guest graphics, guest console, and the QEMU 2041 monitor in a window. With this option, QEMU can display the VGA 2042 output when in text mode using a curses/ncurses interface. Nothing 2043 is displayed in graphical mode. 2044ERST 2045 2046DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 2047 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 2048 QEMU_ARCH_ALL) 2049SRST 2050``-alt-grab`` 2051 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 2052 this also affects the special keys (for fullscreen, monitor-mode 2053 switching, etc). This option is deprecated - please use 2054 ``-display sdl,grab-mod=lshift-lctrl-lalt`` instead. 2055ERST 2056 2057DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 2058 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 2059 QEMU_ARCH_ALL) 2060SRST 2061``-ctrl-grab`` 2062 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 2063 also affects the special keys (for fullscreen, monitor-mode 2064 switching, etc). This option is deprecated - please use 2065 ``-display sdl,grab-mod=rctrl`` instead. 2066ERST 2067 2068DEF("sdl", 0, QEMU_OPTION_sdl, 2069 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 2070SRST 2071``-sdl`` 2072 Enable SDL. 2073ERST 2074 2075DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2076 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2077 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2078 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2079 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2080 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2081 " [,tls-ciphers=<list>]\n" 2082 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2083 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2084 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2085 " [,password=<string>][,password-secret=<secret-id>]\n" 2086 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2087 " [,jpeg-wan-compression=[auto|never|always]]\n" 2088 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2089 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2090 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2091 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2092 " [,gl=[on|off]][,rendernode=<file>]\n" 2093 " enable spice\n" 2094 " at least one of {port, tls-port} is mandatory\n", 2095 QEMU_ARCH_ALL) 2096SRST 2097``-spice option[,option[,...]]`` 2098 Enable the spice remote desktop protocol. Valid options are 2099 2100 ``port=<nr>`` 2101 Set the TCP port spice is listening on for plaintext channels. 2102 2103 ``addr=<addr>`` 2104 Set the IP address spice is listening on. Default is any 2105 address. 2106 2107 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2108 Force using the specified IP version. 2109 2110 ``password=<string>`` 2111 Set the password you need to authenticate. 2112 2113 This option is deprecated and insecure because it leaves the 2114 password visible in the process listing. Use ``password-secret`` 2115 instead. 2116 2117 ``password-secret=<secret-id>`` 2118 Set the ID of the ``secret`` object containing the password 2119 you need to authenticate. 2120 2121 ``sasl=on|off`` 2122 Require that the client use SASL to authenticate with the spice. 2123 The exact choice of authentication method used is controlled 2124 from the system / user's SASL configuration file for the 'qemu' 2125 service. This is typically found in /etc/sasl2/qemu.conf. If 2126 running QEMU as an unprivileged user, an environment variable 2127 SASL\_CONF\_PATH can be used to make it search alternate 2128 locations for the service config. While some SASL auth methods 2129 can also provide data encryption (eg GSSAPI), it is recommended 2130 that SASL always be combined with the 'tls' and 'x509' settings 2131 to enable use of SSL and server certificates. This ensures a 2132 data encryption preventing compromise of authentication 2133 credentials. 2134 2135 ``disable-ticketing=on|off`` 2136 Allow client connects without authentication. 2137 2138 ``disable-copy-paste=on|off`` 2139 Disable copy paste between the client and the guest. 2140 2141 ``disable-agent-file-xfer=on|off`` 2142 Disable spice-vdagent based file-xfer between the client and the 2143 guest. 2144 2145 ``tls-port=<nr>`` 2146 Set the TCP port spice is listening on for encrypted channels. 2147 2148 ``x509-dir=<dir>`` 2149 Set the x509 file directory. Expects same filenames as -vnc 2150 $display,x509=$dir 2151 2152 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2153 The x509 file names can also be configured individually. 2154 2155 ``tls-ciphers=<list>`` 2156 Specify which ciphers to use. 2157 2158 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2159 Force specific channel to be used with or without TLS 2160 encryption. The options can be specified multiple times to 2161 configure multiple channels. The special name "default" can be 2162 used to set the default mode. For channels which are not 2163 explicitly forced into one mode the spice client is allowed to 2164 pick tls/plaintext as he pleases. 2165 2166 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2167 Configure image compression (lossless). Default is auto\_glz. 2168 2169 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2170 Configure wan image compression (lossy for slow links). Default 2171 is auto. 2172 2173 ``streaming-video=[off|all|filter]`` 2174 Configure video stream detection. Default is off. 2175 2176 ``agent-mouse=[on|off]`` 2177 Enable/disable passing mouse events via vdagent. Default is on. 2178 2179 ``playback-compression=[on|off]`` 2180 Enable/disable audio stream compression (using celt 0.5.1). 2181 Default is on. 2182 2183 ``seamless-migration=[on|off]`` 2184 Enable/disable spice seamless migration. Default is off. 2185 2186 ``gl=[on|off]`` 2187 Enable/disable OpenGL context. Default is off. 2188 2189 ``rendernode=<file>`` 2190 DRM render node for OpenGL rendering. If not specified, it will 2191 pick the first available. (Since 2.9) 2192ERST 2193 2194DEF("portrait", 0, QEMU_OPTION_portrait, 2195 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2196 QEMU_ARCH_ALL) 2197SRST 2198``-portrait`` 2199 Rotate graphical output 90 deg left (only PXA LCD). 2200ERST 2201 2202DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2203 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2204 QEMU_ARCH_ALL) 2205SRST 2206``-rotate deg`` 2207 Rotate graphical output some deg left (only PXA LCD). 2208ERST 2209 2210DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2211 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2212 " select video card type\n", QEMU_ARCH_ALL) 2213SRST 2214``-vga type`` 2215 Select type of VGA card to emulate. Valid values for type are 2216 2217 ``cirrus`` 2218 Cirrus Logic GD5446 Video card. All Windows versions starting 2219 from Windows 95 should recognize and use this graphic card. For 2220 optimal performances, use 16 bit color depth in the guest and 2221 the host OS. (This card was the default before QEMU 2.2) 2222 2223 ``std`` 2224 Standard VGA card with Bochs VBE extensions. If your guest OS 2225 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2226 you want to use high resolution modes (>= 1280x1024x16) then you 2227 should use this option. (This card is the default since QEMU 2228 2.2) 2229 2230 ``vmware`` 2231 VMWare SVGA-II compatible adapter. Use it if you have 2232 sufficiently recent XFree86/XOrg server or Windows guest with a 2233 driver for this card. 2234 2235 ``qxl`` 2236 QXL paravirtual graphic card. It is VGA compatible (including 2237 VESA 2.0 VBE support). Works best with qxl guest drivers 2238 installed though. Recommended choice when using the spice 2239 protocol. 2240 2241 ``tcx`` 2242 (sun4m only) Sun TCX framebuffer. This is the default 2243 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2244 colour depths at a fixed resolution of 1024x768. 2245 2246 ``cg3`` 2247 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2248 framebuffer for sun4m machines available in both 1024x768 2249 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2250 wishing to run older Solaris versions. 2251 2252 ``virtio`` 2253 Virtio VGA card. 2254 2255 ``none`` 2256 Disable VGA card. 2257ERST 2258 2259DEF("full-screen", 0, QEMU_OPTION_full_screen, 2260 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2261SRST 2262``-full-screen`` 2263 Start in full screen. 2264ERST 2265 2266DEF("g", HAS_ARG, QEMU_OPTION_g , 2267 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2268 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2269SRST 2270``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2271 Set the initial graphical resolution and depth (PPC, SPARC only). 2272 2273 For PPC the default is 800x600x32. 2274 2275 For SPARC with the TCX graphics device, the default is 1024x768x8 2276 with the option of 1024x768x24. For cgthree, the default is 2277 1024x768x8 with the option of 1152x900x8 for people who wish to use 2278 OBP. 2279ERST 2280 2281DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2282 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2283SRST 2284``-vnc display[,option[,option[,...]]]`` 2285 Normally, if QEMU is compiled with graphical window support, it 2286 displays output such as guest graphics, guest console, and the QEMU 2287 monitor in a window. With this option, you can have QEMU listen on 2288 VNC display display and redirect the VGA display over the VNC 2289 session. It is very useful to enable the usb tablet device when 2290 using this option (option ``-device usb-tablet``). When using the 2291 VNC display, you must use the ``-k`` parameter to set the keyboard 2292 layout if you are not using en-us. Valid syntax for the display is 2293 2294 ``to=L`` 2295 With this option, QEMU will try next available VNC displays, 2296 until the number L, if the origianlly defined "-vnc display" is 2297 not available, e.g. port 5900+display is already used by another 2298 application. By default, to=0. 2299 2300 ``host:d`` 2301 TCP connections will only be allowed from host on display d. By 2302 convention the TCP port is 5900+d. Optionally, host can be 2303 omitted in which case the server will accept connections from 2304 any host. 2305 2306 ``unix:path`` 2307 Connections will be allowed over UNIX domain sockets where path 2308 is the location of a unix socket to listen for connections on. 2309 2310 ``none`` 2311 VNC is initialized but not started. The monitor ``change`` 2312 command can be used to later start the VNC server. 2313 2314 Following the display value there may be one or more option flags 2315 separated by commas. Valid options are 2316 2317 ``reverse=on|off`` 2318 Connect to a listening VNC client via a "reverse" connection. 2319 The client is specified by the display. For reverse network 2320 connections (host:d,``reverse``), the d argument is a TCP port 2321 number, not a display number. 2322 2323 ``websocket=on|off`` 2324 Opens an additional TCP listening port dedicated to VNC 2325 Websocket connections. If a bare websocket option is given, the 2326 Websocket port is 5700+display. An alternative port can be 2327 specified with the syntax ``websocket``\ =port. 2328 2329 If host is specified connections will only be allowed from this 2330 host. It is possible to control the websocket listen address 2331 independently, using the syntax ``websocket``\ =host:port. 2332 2333 If no TLS credentials are provided, the websocket connection 2334 runs in unencrypted mode. If TLS credentials are provided, the 2335 websocket connection requires encrypted client connections. 2336 2337 ``password=on|off`` 2338 Require that password based authentication is used for client 2339 connections. 2340 2341 The password must be set separately using the ``set_password`` 2342 command in the :ref:`QEMU monitor`. The 2343 syntax to change your password is: 2344 ``set_password <protocol> <password>`` where <protocol> could be 2345 either "vnc" or "spice". 2346 2347 If you would like to change <protocol> password expiration, you 2348 should use ``expire_password <protocol> <expiration-time>`` 2349 where expiration time could be one of the following options: 2350 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2351 make password expire in 60 seconds, or 1335196800 to make 2352 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2353 this date and time). 2354 2355 You can also use keywords "now" or "never" for the expiration 2356 time to allow <protocol> password to expire immediately or never 2357 expire. 2358 2359 ``password-secret=<secret-id>`` 2360 Require that password based authentication is used for client 2361 connections, using the password provided by the ``secret`` 2362 object identified by ``secret-id``. 2363 2364 ``tls-creds=ID`` 2365 Provides the ID of a set of TLS credentials to use to secure the 2366 VNC server. They will apply to both the normal VNC server socket 2367 and the websocket socket (if enabled). Setting TLS credentials 2368 will cause the VNC server socket to enable the VeNCrypt auth 2369 mechanism. The credentials should have been previously created 2370 using the ``-object tls-creds`` argument. 2371 2372 ``tls-authz=ID`` 2373 Provides the ID of the QAuthZ authorization object against which 2374 the client's x509 distinguished name will validated. This object 2375 is only resolved at time of use, so can be deleted and recreated 2376 on the fly while the VNC server is active. If missing, it will 2377 default to denying access. 2378 2379 ``sasl=on|off`` 2380 Require that the client use SASL to authenticate with the VNC 2381 server. The exact choice of authentication method used is 2382 controlled from the system / user's SASL configuration file for 2383 the 'qemu' service. This is typically found in 2384 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2385 an environment variable SASL\_CONF\_PATH can be used to make it 2386 search alternate locations for the service config. While some 2387 SASL auth methods can also provide data encryption (eg GSSAPI), 2388 it is recommended that SASL always be combined with the 'tls' 2389 and 'x509' settings to enable use of SSL and server 2390 certificates. This ensures a data encryption preventing 2391 compromise of authentication credentials. See the 2392 :ref:`VNC security` section in the System Emulation Users Guide 2393 for details on using SASL authentication. 2394 2395 ``sasl-authz=ID`` 2396 Provides the ID of the QAuthZ authorization object against which 2397 the client's SASL username will validated. This object is only 2398 resolved at time of use, so can be deleted and recreated on the 2399 fly while the VNC server is active. If missing, it will default 2400 to denying access. 2401 2402 ``acl=on|off`` 2403 Legacy method for enabling authorization of clients against the 2404 x509 distinguished name and SASL username. It results in the 2405 creation of two ``authz-list`` objects with IDs of 2406 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2407 objects must be configured with the HMP ACL commands. 2408 2409 This option is deprecated and should no longer be used. The new 2410 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2411 2412 ``lossy=on|off`` 2413 Enable lossy compression methods (gradient, JPEG, ...). If this 2414 option is set, VNC client may receive lossy framebuffer updates 2415 depending on its encoding settings. Enabling this option can 2416 save a lot of bandwidth at the expense of quality. 2417 2418 ``non-adaptive=on|off`` 2419 Disable adaptive encodings. Adaptive encodings are enabled by 2420 default. An adaptive encoding will try to detect frequently 2421 updated screen regions, and send updates in these regions using 2422 a lossy encoding (like JPEG). This can be really helpful to save 2423 bandwidth when playing videos. Disabling adaptive encodings 2424 restores the original static behavior of encodings like Tight. 2425 2426 ``share=[allow-exclusive|force-shared|ignore]`` 2427 Set display sharing policy. 'allow-exclusive' allows clients to 2428 ask for exclusive access. As suggested by the rfb spec this is 2429 implemented by dropping other connections. Connecting multiple 2430 clients in parallel requires all clients asking for a shared 2431 session (vncviewer: -shared switch). This is the default. 2432 'force-shared' disables exclusive client access. Useful for 2433 shared desktop sessions, where you don't want someone forgetting 2434 specify -shared disconnect everybody else. 'ignore' completely 2435 ignores the shared flag and allows everybody connect 2436 unconditionally. Doesn't conform to the rfb spec but is 2437 traditional QEMU behavior. 2438 2439 ``key-delay-ms`` 2440 Set keyboard delay, for key down and key up events, in 2441 milliseconds. Default is 10. Keyboards are low-bandwidth 2442 devices, so this slowdown can help the device and guest to keep 2443 up and not lose events in case events are arriving in bulk. 2444 Possible causes for the latter are flaky network connections, or 2445 scripts for automated testing. 2446 2447 ``audiodev=audiodev`` 2448 Use the specified audiodev when the VNC client requests audio 2449 transmission. When not using an -audiodev argument, this option 2450 must be omitted, otherwise is must be present and specify a 2451 valid audiodev. 2452 2453 ``power-control=on|off`` 2454 Permit the remote client to issue shutdown, reboot or reset power 2455 control requests. 2456ERST 2457 2458ARCHHEADING(, QEMU_ARCH_I386) 2459 2460ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2461 2462DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2463 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2464 QEMU_ARCH_I386) 2465SRST 2466``-win2k-hack`` 2467 Use it when installing Windows 2000 to avoid a disk full bug. After 2468 Windows 2000 is installed, you no longer need this option (this 2469 option slows down the IDE transfers). 2470ERST 2471 2472DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2473 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2474 QEMU_ARCH_I386) 2475SRST 2476``-no-fd-bootchk`` 2477 Disable boot signature checking for floppy disks in BIOS. May be 2478 needed to boot from old floppy disks. 2479ERST 2480 2481DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2482 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2483SRST 2484``-no-acpi`` 2485 Disable ACPI (Advanced Configuration and Power Interface) support. 2486 Use it if your guest OS complains about ACPI problems (PC target 2487 machine only). 2488ERST 2489 2490DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2491 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2492SRST 2493``-no-hpet`` 2494 Disable HPET support. 2495ERST 2496 2497DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2498 "-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" 2499 " ACPI table description\n", QEMU_ARCH_I386) 2500SRST 2501``-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]...]`` 2502 Add ACPI table with specified header fields and context from 2503 specified files. For file=, take whole ACPI table from the specified 2504 files, including all ACPI headers (possible overridden by other 2505 options). For data=, only data portion of the table is used, all 2506 header information is specified in the command line. If a SLIC table 2507 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2508 fields will override the same in the RSDT and the FADT (a.k.a. 2509 FACP), in order to ensure the field matches required by the 2510 Microsoft SLIC spec and the ACPI spec. 2511ERST 2512 2513DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2514 "-smbios file=binary\n" 2515 " load SMBIOS entry from binary file\n" 2516 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2517 " [,uefi=on|off]\n" 2518 " specify SMBIOS type 0 fields\n" 2519 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2520 " [,uuid=uuid][,sku=str][,family=str]\n" 2521 " specify SMBIOS type 1 fields\n" 2522 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2523 " [,asset=str][,location=str]\n" 2524 " specify SMBIOS type 2 fields\n" 2525 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2526 " [,sku=str]\n" 2527 " specify SMBIOS type 3 fields\n" 2528 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2529 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2530 " specify SMBIOS type 4 fields\n" 2531 "-smbios type=11[,value=str][,path=filename]\n" 2532 " specify SMBIOS type 11 fields\n" 2533 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2534 " [,asset=str][,part=str][,speed=%d]\n" 2535 " specify SMBIOS type 17 fields\n" 2536 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2537 " specify SMBIOS type 41 fields\n", 2538 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2539SRST 2540``-smbios file=binary`` 2541 Load SMBIOS entry from binary file. 2542 2543``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2544 Specify SMBIOS type 0 fields 2545 2546``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2547 Specify SMBIOS type 1 fields 2548 2549``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2550 Specify SMBIOS type 2 fields 2551 2552``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2553 Specify SMBIOS type 3 fields 2554 2555``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2556 Specify SMBIOS type 4 fields 2557 2558``-smbios type=11[,value=str][,path=filename]`` 2559 Specify SMBIOS type 11 fields 2560 2561 This argument can be repeated multiple times, and values are added in the order they are parsed. 2562 Applications intending to use OEM strings data are encouraged to use their application name as 2563 a prefix for the value string. This facilitates passing information for multiple applications 2564 concurrently. 2565 2566 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2567 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2568 2569 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2570 the SMBIOS table in the order in which they appear. 2571 2572 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2573 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2574 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2575 data set, for example, by specifying the serial ID of a block device. 2576 2577 An example passing three strings is 2578 2579 .. parsed-literal:: 2580 2581 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2582 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2583 path=/some/file/with/oemstringsdata.txt 2584 2585 In the guest OS this is visible with the ``dmidecode`` command 2586 2587 .. parsed-literal:: 2588 2589 $ dmidecode -t 11 2590 Handle 0x0E00, DMI type 11, 5 bytes 2591 OEM Strings 2592 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2593 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2594 String 3: myapp:some extra data 2595 2596 2597``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2598 Specify SMBIOS type 17 fields 2599 2600``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2601 Specify SMBIOS type 41 fields 2602 2603 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2604 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2605 position on the PCI bus. 2606 2607 Here is an example of use: 2608 2609 .. parsed-literal:: 2610 2611 -netdev user,id=internet \\ 2612 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2613 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2614 2615 In the guest OS, the device should then appear as ``eno1``: 2616 2617 ..parsed-literal:: 2618 2619 $ ip -brief l 2620 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2621 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2622 2623 Currently, the PCI device has to be attached to the root bus. 2624 2625ERST 2626 2627DEFHEADING() 2628 2629DEFHEADING(Network options:) 2630 2631DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2632#ifdef CONFIG_SLIRP 2633 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2634 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2635 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2636 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2637 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2638#ifndef _WIN32 2639 "[,smb=dir[,smbserver=addr]]\n" 2640#endif 2641 " configure a user mode network backend with ID 'str',\n" 2642 " its DHCP server and optional services\n" 2643#endif 2644#ifdef _WIN32 2645 "-netdev tap,id=str,ifname=name\n" 2646 " configure a host TAP network backend with ID 'str'\n" 2647#else 2648 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2649 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2650 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2651 " [,poll-us=n]\n" 2652 " configure a host TAP network backend with ID 'str'\n" 2653 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2654 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2655 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2656 " to deconfigure it\n" 2657 " use '[down]script=no' to disable script execution\n" 2658 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2659 " configure it\n" 2660 " use 'fd=h' to connect to an already opened TAP interface\n" 2661 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2662 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2663 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2664 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2665 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2666 " use vhost=on to enable experimental in kernel accelerator\n" 2667 " (only has effect for virtio guests which use MSIX)\n" 2668 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2669 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2670 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2671 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2672 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2673 " spent on busy polling for vhost net\n" 2674 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2675 " configure a host TAP network backend with ID 'str' that is\n" 2676 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2677 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2678#endif 2679#ifdef __linux__ 2680 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2681 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2682 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2683 " [,rxcookie=rxcookie][,offset=offset]\n" 2684 " configure a network backend with ID 'str' connected to\n" 2685 " an Ethernet over L2TPv3 pseudowire.\n" 2686 " Linux kernel 3.3+ as well as most routers can talk\n" 2687 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2688 " VM to a router and even VM to Host. It is a nearly-universal\n" 2689 " standard (RFC3931). Note - this implementation uses static\n" 2690 " pre-configured tunnels (same as the Linux kernel).\n" 2691 " use 'src=' to specify source address\n" 2692 " use 'dst=' to specify destination address\n" 2693 " use 'udp=on' to specify udp encapsulation\n" 2694 " use 'srcport=' to specify source udp port\n" 2695 " use 'dstport=' to specify destination udp port\n" 2696 " use 'ipv6=on' to force v6\n" 2697 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2698 " well as a weak security measure\n" 2699 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2700 " use 'txcookie=0x012345678' to specify a txcookie\n" 2701 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2702 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2703 " use 'pincounter=on' to work around broken counter handling in peer\n" 2704 " use 'offset=X' to add an extra offset between header and data\n" 2705#endif 2706 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2707 " configure a network backend to connect to another network\n" 2708 " using a socket connection\n" 2709 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2710 " configure a network backend to connect to a multicast maddr and port\n" 2711 " use 'localaddr=addr' to specify the host address to send packets from\n" 2712 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2713 " configure a network backend to connect to another network\n" 2714 " using an UDP tunnel\n" 2715#ifdef CONFIG_VDE 2716 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2717 " configure a network backend to connect to port 'n' of a vde switch\n" 2718 " running on host and listening for incoming connections on 'socketpath'.\n" 2719 " Use group 'groupname' and mode 'octalmode' to change default\n" 2720 " ownership and permissions for communication port.\n" 2721#endif 2722#ifdef CONFIG_NETMAP 2723 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2724 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2725 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2726 " netmap device, defaults to '/dev/netmap')\n" 2727#endif 2728#ifdef CONFIG_POSIX 2729 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2730 " configure a vhost-user network, backed by a chardev 'dev'\n" 2731#endif 2732#ifdef __linux__ 2733 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2734 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2735#endif 2736 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2737 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2738DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2739 "-nic [tap|bridge|" 2740#ifdef CONFIG_SLIRP 2741 "user|" 2742#endif 2743#ifdef __linux__ 2744 "l2tpv3|" 2745#endif 2746#ifdef CONFIG_VDE 2747 "vde|" 2748#endif 2749#ifdef CONFIG_NETMAP 2750 "netmap|" 2751#endif 2752#ifdef CONFIG_POSIX 2753 "vhost-user|" 2754#endif 2755 "socket][,option][,...][mac=macaddr]\n" 2756 " initialize an on-board / default host NIC (using MAC address\n" 2757 " macaddr) and connect it to the given host network backend\n" 2758 "-nic none use it alone to have zero network devices (the default is to\n" 2759 " provided a 'user' network connection)\n", 2760 QEMU_ARCH_ALL) 2761DEF("net", HAS_ARG, QEMU_OPTION_net, 2762 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2763 " configure or create an on-board (or machine default) NIC and\n" 2764 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2765 "-net [" 2766#ifdef CONFIG_SLIRP 2767 "user|" 2768#endif 2769 "tap|" 2770 "bridge|" 2771#ifdef CONFIG_VDE 2772 "vde|" 2773#endif 2774#ifdef CONFIG_NETMAP 2775 "netmap|" 2776#endif 2777 "socket][,option][,option][,...]\n" 2778 " old way to initialize a host network interface\n" 2779 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2780SRST 2781``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2782 This option is a shortcut for configuring both the on-board 2783 (default) guest NIC hardware and the host network backend in one go. 2784 The host backend options are the same as with the corresponding 2785 ``-netdev`` options below. The guest NIC model can be set with 2786 ``model=modelname``. Use ``model=help`` to list the available device 2787 types. The hardware MAC address can be set with ``mac=macaddr``. 2788 2789 The following two example do exactly the same, to show how ``-nic`` 2790 can be used to shorten the command line length: 2791 2792 .. parsed-literal:: 2793 2794 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2795 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2796 2797``-nic none`` 2798 Indicate that no network devices should be configured. It is used to 2799 override the default configuration (default NIC with "user" host 2800 network backend) which is activated if no other networking options 2801 are provided. 2802 2803``-netdev user,id=id[,option][,option][,...]`` 2804 Configure user mode host network backend which requires no 2805 administrator privilege to run. Valid options are: 2806 2807 ``id=id`` 2808 Assign symbolic name for use in monitor commands. 2809 2810 ``ipv4=on|off and ipv6=on|off`` 2811 Specify that either IPv4 or IPv6 must be enabled. If neither is 2812 specified both protocols are enabled. 2813 2814 ``net=addr[/mask]`` 2815 Set IP network address the guest will see. Optionally specify 2816 the netmask, either in the form a.b.c.d or as number of valid 2817 top-most bits. Default is 10.0.2.0/24. 2818 2819 ``host=addr`` 2820 Specify the guest-visible address of the host. Default is the 2821 2nd IP in the guest network, i.e. x.x.x.2. 2822 2823 ``ipv6-net=addr[/int]`` 2824 Set IPv6 network address the guest will see (default is 2825 fec0::/64). The network prefix is given in the usual hexadecimal 2826 IPv6 address notation. The prefix size is optional, and is given 2827 as the number of valid top-most bits (default is 64). 2828 2829 ``ipv6-host=addr`` 2830 Specify the guest-visible IPv6 address of the host. Default is 2831 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2832 2833 ``restrict=on|off`` 2834 If this option is enabled, the guest will be isolated, i.e. it 2835 will not be able to contact the host and no guest IP packets 2836 will be routed over the host to the outside. This option does 2837 not affect any explicitly set forwarding rules. 2838 2839 ``hostname=name`` 2840 Specifies the client hostname reported by the built-in DHCP 2841 server. 2842 2843 ``dhcpstart=addr`` 2844 Specify the first of the 16 IPs the built-in DHCP server can 2845 assign. Default is the 15th to 31st IP in the guest network, 2846 i.e. x.x.x.15 to x.x.x.31. 2847 2848 ``dns=addr`` 2849 Specify the guest-visible address of the virtual nameserver. The 2850 address must be different from the host address. Default is the 2851 3rd IP in the guest network, i.e. x.x.x.3. 2852 2853 ``ipv6-dns=addr`` 2854 Specify the guest-visible address of the IPv6 virtual 2855 nameserver. The address must be different from the host address. 2856 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2857 2858 ``dnssearch=domain`` 2859 Provides an entry for the domain-search list sent by the 2860 built-in DHCP server. More than one domain suffix can be 2861 transmitted by specifying this option multiple times. If 2862 supported, this will cause the guest to automatically try to 2863 append the given domain suffix(es) in case a domain name can not 2864 be resolved. 2865 2866 Example: 2867 2868 .. parsed-literal:: 2869 2870 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2871 2872 ``domainname=domain`` 2873 Specifies the client domain name reported by the built-in DHCP 2874 server. 2875 2876 ``tftp=dir`` 2877 When using the user mode network stack, activate a built-in TFTP 2878 server. The files in dir will be exposed as the root of a TFTP 2879 server. The TFTP client on the guest must be configured in 2880 binary mode (use the command ``bin`` of the Unix TFTP client). 2881 2882 ``tftp-server-name=name`` 2883 In BOOTP reply, broadcast name as the "TFTP server name" 2884 (RFC2132 option 66). This can be used to advise the guest to 2885 load boot files or configurations from a different server than 2886 the host address. 2887 2888 ``bootfile=file`` 2889 When using the user mode network stack, broadcast file as the 2890 BOOTP filename. In conjunction with ``tftp``, this can be used 2891 to network boot a guest from a local directory. 2892 2893 Example (using pxelinux): 2894 2895 .. parsed-literal:: 2896 2897 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2898 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2899 2900 ``smb=dir[,smbserver=addr]`` 2901 When using the user mode network stack, activate a built-in SMB 2902 server so that Windows OSes can access to the host files in 2903 ``dir`` transparently. The IP address of the SMB server can be 2904 set to addr. By default the 4th IP in the guest network is used, 2905 i.e. x.x.x.4. 2906 2907 In the guest Windows OS, the line: 2908 2909 :: 2910 2911 10.0.2.4 smbserver 2912 2913 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2914 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2915 NT/2000). 2916 2917 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2918 2919 Note that a SAMBA server must be installed on the host OS. 2920 2921 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2922 Redirect incoming TCP or UDP connections to the host port 2923 hostport to the guest IP address guestaddr on guest port 2924 guestport. If guestaddr is not specified, its value is x.x.x.15 2925 (default first address given by the built-in DHCP server). By 2926 specifying hostaddr, the rule can be bound to a specific host 2927 interface. If no connection type is set, TCP is used. This 2928 option can be given multiple times. 2929 2930 For example, to redirect host X11 connection from screen 1 to 2931 guest screen 0, use the following: 2932 2933 .. parsed-literal:: 2934 2935 # on the host 2936 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2937 # this host xterm should open in the guest X11 server 2938 xterm -display :1 2939 2940 To redirect telnet connections from host port 5555 to telnet 2941 port on the guest, use the following: 2942 2943 .. parsed-literal:: 2944 2945 # on the host 2946 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2947 telnet localhost 5555 2948 2949 Then when you use on the host ``telnet localhost 5555``, you 2950 connect to the guest telnet server. 2951 2952 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2953 Forward guest TCP connections to the IP address server on port 2954 port to the character device dev or to a program executed by 2955 cmd:command which gets spawned for each connection. This option 2956 can be given multiple times. 2957 2958 You can either use a chardev directly and have that one used 2959 throughout QEMU's lifetime, like in the following example: 2960 2961 .. parsed-literal:: 2962 2963 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2964 # the guest accesses it 2965 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2966 2967 Or you can execute a command on every TCP connection established 2968 by the guest, so that QEMU behaves similar to an inetd process 2969 for that virtual server: 2970 2971 .. parsed-literal:: 2972 2973 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2974 # and connect the TCP stream to its stdin/stdout 2975 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2976 2977``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2978 Configure a host TAP network backend with ID id. 2979 2980 Use the network script file to configure it and the network script 2981 dfile to deconfigure it. If name is not provided, the OS 2982 automatically provides one. The default network configure script is 2983 ``/etc/qemu-ifup`` and the default network deconfigure script is 2984 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2985 disable script execution. 2986 2987 If running QEMU as an unprivileged user, use the network helper 2988 to configure the TAP interface and attach it to the bridge. 2989 The default network helper executable is 2990 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2991 ``br0``. 2992 2993 ``fd``\ =h can be used to specify the handle of an already opened 2994 host TAP interface. 2995 2996 Examples: 2997 2998 .. parsed-literal:: 2999 3000 #launch a QEMU instance with the default network script 3001 |qemu_system| linux.img -nic tap 3002 3003 .. parsed-literal:: 3004 3005 #launch a QEMU instance with two NICs, each one connected 3006 #to a TAP device 3007 |qemu_system| linux.img \\ 3008 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3009 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3010 3011 .. parsed-literal:: 3012 3013 #launch a QEMU instance with the default network helper to 3014 #connect a TAP device to bridge br0 3015 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3016 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3017 3018``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3019 Connect a host TAP network interface to a host bridge device. 3020 3021 Use the network helper helper to configure the TAP interface and 3022 attach it to the bridge. The default network helper executable is 3023 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3024 ``br0``. 3025 3026 Examples: 3027 3028 .. parsed-literal:: 3029 3030 #launch a QEMU instance with the default network helper to 3031 #connect a TAP device to bridge br0 3032 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3033 3034 .. parsed-literal:: 3035 3036 #launch a QEMU instance with the default network helper to 3037 #connect a TAP device to bridge qemubr0 3038 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3039 3040``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3041 This host network backend can be used to connect the guest's network 3042 to another QEMU virtual machine using a TCP socket connection. If 3043 ``listen`` is specified, QEMU waits for incoming connections on port 3044 (host is optional). ``connect`` is used to connect to another QEMU 3045 instance using the ``listen`` option. ``fd``\ =h specifies an 3046 already opened TCP socket. 3047 3048 Example: 3049 3050 .. parsed-literal:: 3051 3052 # launch a first QEMU instance 3053 |qemu_system| linux.img \\ 3054 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3055 -netdev socket,id=n1,listen=:1234 3056 # connect the network of this instance to the network of the first instance 3057 |qemu_system| linux.img \\ 3058 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3059 -netdev socket,id=n2,connect=127.0.0.1:1234 3060 3061``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3062 Configure a socket host network backend to share the guest's network 3063 traffic with another QEMU virtual machines using a UDP multicast 3064 socket, effectively making a bus for every QEMU with same multicast 3065 address maddr and port. NOTES: 3066 3067 1. Several QEMU can be running on different hosts and share same bus 3068 (assuming correct multicast setup for these hosts). 3069 3070 2. mcast support is compatible with User Mode Linux (argument 3071 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3072 3073 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3074 3075 Example: 3076 3077 .. parsed-literal:: 3078 3079 # launch one QEMU instance 3080 |qemu_system| linux.img \\ 3081 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3082 -netdev socket,id=n1,mcast=230.0.0.1:1234 3083 # launch another QEMU instance on same "bus" 3084 |qemu_system| linux.img \\ 3085 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3086 -netdev socket,id=n2,mcast=230.0.0.1:1234 3087 # launch yet another QEMU instance on same "bus" 3088 |qemu_system| linux.img \\ 3089 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3090 -netdev socket,id=n3,mcast=230.0.0.1:1234 3091 3092 Example (User Mode Linux compat.): 3093 3094 .. parsed-literal:: 3095 3096 # launch QEMU instance (note mcast address selected is UML's default) 3097 |qemu_system| linux.img \\ 3098 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3099 -netdev socket,id=n1,mcast=239.192.168.1:1102 3100 # launch UML 3101 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3102 3103 Example (send packets from host's 1.2.3.4): 3104 3105 .. parsed-literal:: 3106 3107 |qemu_system| linux.img \\ 3108 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3109 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3110 3111``-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]`` 3112 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3113 is a popular protocol to transport Ethernet (and other Layer 2) data 3114 frames between two systems. It is present in routers, firewalls and 3115 the Linux kernel (from version 3.3 onwards). 3116 3117 This transport allows a VM to communicate to another VM, router or 3118 firewall directly. 3119 3120 ``src=srcaddr`` 3121 source address (mandatory) 3122 3123 ``dst=dstaddr`` 3124 destination address (mandatory) 3125 3126 ``udp`` 3127 select udp encapsulation (default is ip). 3128 3129 ``srcport=srcport`` 3130 source udp port. 3131 3132 ``dstport=dstport`` 3133 destination udp port. 3134 3135 ``ipv6`` 3136 force v6, otherwise defaults to v4. 3137 3138 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3139 Cookies are a weak form of security in the l2tpv3 specification. 3140 Their function is mostly to prevent misconfiguration. By default 3141 they are 32 bit. 3142 3143 ``cookie64`` 3144 Set cookie size to 64 bit instead of the default 32 3145 3146 ``counter=off`` 3147 Force a 'cut-down' L2TPv3 with no counter as in 3148 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3149 3150 ``pincounter=on`` 3151 Work around broken counter handling in peer. This may also help 3152 on networks which have packet reorder. 3153 3154 ``offset=offset`` 3155 Add an extra offset between header and data 3156 3157 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3158 the bridge br-lan on the remote Linux host 1.2.3.4: 3159 3160 .. parsed-literal:: 3161 3162 # Setup tunnel on linux host using raw ip as encapsulation 3163 # on 1.2.3.4 3164 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3165 encap udp udp_sport 16384 udp_dport 16384 3166 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3167 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3168 ifconfig vmtunnel0 mtu 1500 3169 ifconfig vmtunnel0 up 3170 brctl addif br-lan vmtunnel0 3171 3172 3173 # on 4.3.2.1 3174 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3175 3176 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3177 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3178 3179``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3180 Configure VDE backend to connect to PORT n of a vde switch running 3181 on host and listening for incoming connections on socketpath. Use 3182 GROUP groupname and MODE octalmode to change default ownership and 3183 permissions for communication port. This option is only available if 3184 QEMU has been compiled with vde support enabled. 3185 3186 Example: 3187 3188 .. parsed-literal:: 3189 3190 # launch vde switch 3191 vde_switch -F -sock /tmp/myswitch 3192 # launch QEMU instance 3193 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3194 3195``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3196 Establish a vhost-user netdev, backed by a chardev id. The chardev 3197 should be a unix domain socket backed one. The vhost-user uses a 3198 specifically defined protocol to pass vhost ioctl replacement 3199 messages to an application on the other end of the socket. On 3200 non-MSIX guests, the feature can be forced with vhostforce. Use 3201 'queues=n' to specify the number of queues to be created for 3202 multiqueue vhost-user. 3203 3204 Example: 3205 3206 :: 3207 3208 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3209 -numa node,memdev=mem \ 3210 -chardev socket,id=chr0,path=/path/to/socket \ 3211 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3212 -device virtio-net-pci,netdev=net0 3213 3214``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3215 Establish a vhost-vdpa netdev. 3216 3217 vDPA device is a device that uses a datapath which complies with 3218 the virtio specifications with a vendor specific control path. 3219 vDPA devices can be both physically located on the hardware or 3220 emulated by software. 3221 3222``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3223 Create a hub port on the emulated hub with ID hubid. 3224 3225 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3226 instead of a single netdev. Alternatively, you can also connect the 3227 hubport to another netdev with ID nd by using the ``netdev=nd`` 3228 option. 3229 3230``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3231 Legacy option to configure or create an on-board (or machine 3232 default) Network Interface Card(NIC) and connect it either to the 3233 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3234 If model is omitted, then the default NIC model associated with the 3235 machine type is used. Note that the default NIC model may change in 3236 future QEMU releases, so it is highly recommended to always specify 3237 a model. Optionally, the MAC address can be changed to mac, the 3238 device address set to addr (PCI cards only), and a name can be 3239 assigned for use in monitor commands. Optionally, for PCI cards, you 3240 can specify the number v of MSI-X vectors that the card should have; 3241 this option currently only affects virtio cards; set v = 0 to 3242 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3243 created. QEMU can emulate several different models of network card. 3244 Use ``-net nic,model=help`` for a list of available devices for your 3245 target. 3246 3247``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3248 Configure a host network backend (with the options corresponding to 3249 the same ``-netdev`` option) and connect it to the emulated hub 0 3250 (the default hub). Use name to specify the name of the hub port. 3251ERST 3252 3253DEFHEADING() 3254 3255DEFHEADING(Character device options:) 3256 3257DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3258 "-chardev help\n" 3259 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3260 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3261 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3262 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3263 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3264 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3265 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3266 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3267 " [,logfile=PATH][,logappend=on|off]\n" 3268 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3269 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3270 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3271 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3272 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3273 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3274#ifdef _WIN32 3275 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3276 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3277#else 3278 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3279 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3280#endif 3281#ifdef CONFIG_BRLAPI 3282 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3283#endif 3284#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3285 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3286 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3287 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3288#endif 3289#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3290 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3291 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3292#endif 3293#if defined(CONFIG_SPICE) 3294 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3295 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3296#endif 3297 , QEMU_ARCH_ALL 3298) 3299 3300SRST 3301The general form of a character device option is: 3302 3303``-chardev backend,id=id[,mux=on|off][,options]`` 3304 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3305 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3306 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3307 ``spicevmc``, ``spiceport``. The specific backend will determine the 3308 applicable options. 3309 3310 Use ``-chardev help`` to print all available chardev backend types. 3311 3312 All devices must have an id, which can be any string up to 127 3313 characters long. It is used to uniquely identify this device in 3314 other command line directives. 3315 3316 A character device may be used in multiplexing mode by multiple 3317 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3318 a "1:N" device, and here the "1" end is your specified chardev 3319 backend, and the "N" end is the various parts of QEMU that can talk 3320 to a chardev. If you create a chardev with ``id=myid`` and 3321 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3322 and you can then configure multiple front ends to use that chardev 3323 ID for their input/output. Up to four different front ends can be 3324 connected to a single multiplexed chardev. (Without multiplexing 3325 enabled, a chardev can only be used by a single front end.) For 3326 instance you could use this to allow a single stdio chardev to be 3327 used by two serial ports and the QEMU monitor: 3328 3329 :: 3330 3331 -chardev stdio,mux=on,id=char0 \ 3332 -mon chardev=char0,mode=readline \ 3333 -serial chardev:char0 \ 3334 -serial chardev:char0 3335 3336 You can have more than one multiplexer in a system configuration; 3337 for instance you could have a TCP port multiplexed between UART 0 3338 and UART 1, and stdio multiplexed between the QEMU monitor and a 3339 parallel port: 3340 3341 :: 3342 3343 -chardev stdio,mux=on,id=char0 \ 3344 -mon chardev=char0,mode=readline \ 3345 -parallel chardev:char0 \ 3346 -chardev tcp,...,mux=on,id=char1 \ 3347 -serial chardev:char1 \ 3348 -serial chardev:char1 3349 3350 When you're using a multiplexed character device, some escape 3351 sequences are interpreted in the input. See the chapter about 3352 :ref:`keys in the character backend multiplexer` in the 3353 System Emulation Users Guide for more details. 3354 3355 Note that some other command line options may implicitly create 3356 multiplexed character backends; for instance ``-serial mon:stdio`` 3357 creates a multiplexed stdio backend connected to the serial port and 3358 the QEMU monitor, and ``-nographic`` also multiplexes the console 3359 and the monitor to stdio. 3360 3361 There is currently no support for multiplexing in the other 3362 direction (where a single QEMU front end takes input and output from 3363 multiple chardevs). 3364 3365 Every backend supports the ``logfile`` option, which supplies the 3366 path to a file to record all data transmitted via the backend. The 3367 ``logappend`` option controls whether the log file will be truncated 3368 or appended to when opened. 3369 3370The available backends are: 3371 3372``-chardev null,id=id`` 3373 A void device. This device will not emit any data, and will drop any 3374 data it receives. The null backend does not take any options. 3375 3376``-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]`` 3377 Create a two-way stream socket, which can be either a TCP or a unix 3378 socket. A unix socket will be created if ``path`` is specified. 3379 Behaviour is undefined if TCP options are specified for a unix 3380 socket. 3381 3382 ``server=on|off`` specifies that the socket shall be a listening socket. 3383 3384 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3385 to connect to a listening socket. 3386 3387 ``telnet=on|off`` specifies that traffic on the socket should interpret 3388 telnet escape sequences. 3389 3390 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3391 communication. 3392 3393 ``reconnect`` sets the timeout for reconnecting on non-server 3394 sockets when the remote end goes away. qemu will delay this many 3395 seconds and then attempt to reconnect. Zero disables reconnecting, 3396 and is the default. 3397 3398 ``tls-creds`` requests enablement of the TLS protocol for 3399 encryption, and specifies the id of the TLS credentials to use for 3400 the handshake. The credentials must be previously created with the 3401 ``-object tls-creds`` argument. 3402 3403 ``tls-auth`` provides the ID of the QAuthZ authorization object 3404 against which the client's x509 distinguished name will be 3405 validated. This object is only resolved at time of use, so can be 3406 deleted and recreated on the fly while the chardev server is active. 3407 If missing, it will default to denying access. 3408 3409 TCP and unix socket options are given below: 3410 3411 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3412 ``host`` for a listening socket specifies the local address to 3413 be bound. For a connecting socket species the remote host to 3414 connect to. ``host`` is optional for listening sockets. If not 3415 specified it defaults to ``0.0.0.0``. 3416 3417 ``port`` for a listening socket specifies the local port to be 3418 bound. For a connecting socket specifies the port on the remote 3419 host to connect to. ``port`` can be given as either a port 3420 number or a service name. ``port`` is required. 3421 3422 ``to`` is only relevant to listening sockets. If it is 3423 specified, and ``port`` cannot be bound, QEMU will attempt to 3424 bind to subsequent ports up to and including ``to`` until it 3425 succeeds. ``to`` must be specified as a port number. 3426 3427 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3428 or IPv6 must be used. If neither is specified the socket may 3429 use either protocol. 3430 3431 ``nodelay=on|off`` disables the Nagle algorithm. 3432 3433 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3434 ``path`` specifies the local path of the unix socket. ``path`` 3435 is required. 3436 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3437 rather than the filesystem. Optional, defaults to false. 3438 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3439 rather than the full sun_path length. Optional, defaults to true. 3440 3441``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3442 Sends all traffic from the guest to a remote host over UDP. 3443 3444 ``host`` specifies the remote host to connect to. If not specified 3445 it defaults to ``localhost``. 3446 3447 ``port`` specifies the port on the remote host to connect to. 3448 ``port`` is required. 3449 3450 ``localaddr`` specifies the local address to bind to. If not 3451 specified it defaults to ``0.0.0.0``. 3452 3453 ``localport`` specifies the local port to bind to. If not specified 3454 any available local port will be used. 3455 3456 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3457 If neither is specified the device may use either protocol. 3458 3459``-chardev msmouse,id=id`` 3460 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3461 does not take any options. 3462 3463``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3464 Connect to a QEMU text console. ``vc`` may optionally be given a 3465 specific size. 3466 3467 ``width`` and ``height`` specify the width and height respectively 3468 of the console, in pixels. 3469 3470 ``cols`` and ``rows`` specify that the console be sized to fit a 3471 text console with the given dimensions. 3472 3473``-chardev ringbuf,id=id[,size=size]`` 3474 Create a ring buffer with fixed size ``size``. size must be a power 3475 of two and defaults to ``64K``. 3476 3477``-chardev file,id=id,path=path`` 3478 Log all traffic received from the guest to a file. 3479 3480 ``path`` specifies the path of the file to be opened. This file will 3481 be created if it does not already exist, and overwritten if it does. 3482 ``path`` is required. 3483 3484``-chardev pipe,id=id,path=path`` 3485 Create a two-way connection to the guest. The behaviour differs 3486 slightly between Windows hosts and other hosts: 3487 3488 On Windows, a single duplex pipe will be created at 3489 ``\\.pipe\path``. 3490 3491 On other hosts, 2 pipes will be created called ``path.in`` and 3492 ``path.out``. Data written to ``path.in`` will be received by the 3493 guest. Data written by the guest can be read from ``path.out``. QEMU 3494 will not create these fifos, and requires them to be present. 3495 3496 ``path`` forms part of the pipe path as described above. ``path`` is 3497 required. 3498 3499``-chardev console,id=id`` 3500 Send traffic from the guest to QEMU's standard output. ``console`` 3501 does not take any options. 3502 3503 ``console`` is only available on Windows hosts. 3504 3505``-chardev serial,id=id,path=path`` 3506 Send traffic from the guest to a serial device on the host. 3507 3508 On Unix hosts serial will actually accept any tty device, not only 3509 serial lines. 3510 3511 ``path`` specifies the name of the serial device to open. 3512 3513``-chardev pty,id=id`` 3514 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3515 does not take any options. 3516 3517 ``pty`` is not available on Windows hosts. 3518 3519``-chardev stdio,id=id[,signal=on|off]`` 3520 Connect to standard input and standard output of the QEMU process. 3521 3522 ``signal`` controls if signals are enabled on the terminal, that 3523 includes exiting QEMU with the key sequence Control-c. This option 3524 is enabled by default, use ``signal=off`` to disable it. 3525 3526``-chardev braille,id=id`` 3527 Connect to a local BrlAPI server. ``braille`` does not take any 3528 options. 3529 3530``-chardev tty,id=id,path=path`` 3531 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3532 and DragonFlyBSD hosts. It is an alias for ``serial``. 3533 3534 ``path`` specifies the path to the tty. ``path`` is required. 3535 3536``-chardev parallel,id=id,path=path`` 3537 \ 3538``-chardev parport,id=id,path=path`` 3539 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3540 hosts. 3541 3542 Connect to a local parallel port. 3543 3544 ``path`` specifies the path to the parallel port device. ``path`` is 3545 required. 3546 3547``-chardev spicevmc,id=id,debug=debug,name=name`` 3548 ``spicevmc`` is only available when spice support is built in. 3549 3550 ``debug`` debug level for spicevmc 3551 3552 ``name`` name of spice channel to connect to 3553 3554 Connect to a spice virtual machine channel, such as vdiport. 3555 3556``-chardev spiceport,id=id,debug=debug,name=name`` 3557 ``spiceport`` is only available when spice support is built in. 3558 3559 ``debug`` debug level for spicevmc 3560 3561 ``name`` name of spice port to connect to 3562 3563 Connect to a spice port, allowing a Spice client to handle the 3564 traffic identified by a name (preferably a fqdn). 3565ERST 3566 3567DEFHEADING() 3568 3569#ifdef CONFIG_TPM 3570DEFHEADING(TPM device options:) 3571 3572DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3573 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3574 " use path to provide path to a character device; default is /dev/tpm0\n" 3575 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3576 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3577 "-tpmdev emulator,id=id,chardev=dev\n" 3578 " configure the TPM device using chardev backend\n", 3579 QEMU_ARCH_ALL) 3580SRST 3581The general form of a TPM device option is: 3582 3583``-tpmdev backend,id=id[,options]`` 3584 The specific backend type will determine the applicable options. The 3585 ``-tpmdev`` option creates the TPM backend and requires a 3586 ``-device`` option that specifies the TPM frontend interface model. 3587 3588 Use ``-tpmdev help`` to print all available TPM backend types. 3589 3590The available backends are: 3591 3592``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3593 (Linux-host only) Enable access to the host's TPM using the 3594 passthrough driver. 3595 3596 ``path`` specifies the path to the host's TPM device, i.e., on a 3597 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3598 default ``/dev/tpm0`` is used. 3599 3600 ``cancel-path`` specifies the path to the host TPM device's sysfs 3601 entry allowing for cancellation of an ongoing TPM command. 3602 ``cancel-path`` is optional and by default QEMU will search for the 3603 sysfs entry to use. 3604 3605 Some notes about using the host's TPM with the passthrough driver: 3606 3607 The TPM device accessed by the passthrough driver must not be used 3608 by any other application on the host. 3609 3610 Since the host's firmware (BIOS/UEFI) has already initialized the 3611 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3612 the TPM again and may therefore not show a TPM-specific menu that 3613 would otherwise allow the user to configure the TPM, e.g., allow the 3614 user to enable/disable or activate/deactivate the TPM. Further, if 3615 TPM ownership is released from within a VM then the host's TPM will 3616 get disabled and deactivated. To enable and activate the TPM again 3617 afterwards, the host has to be rebooted and the user is required to 3618 enter the firmware's menu to enable and activate the TPM. If the TPM 3619 is left disabled and/or deactivated most TPM commands will fail. 3620 3621 To create a passthrough TPM use the following two options: 3622 3623 :: 3624 3625 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3626 3627 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3628 ``tpmdev=tpm0`` in the device option. 3629 3630``-tpmdev emulator,id=id,chardev=dev`` 3631 (Linux-host only) Enable access to a TPM emulator using Unix domain 3632 socket based chardev backend. 3633 3634 ``chardev`` specifies the unique ID of a character device backend 3635 that provides connection to the software TPM server. 3636 3637 To create a TPM emulator backend device with chardev socket backend: 3638 3639 :: 3640 3641 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3642ERST 3643 3644DEFHEADING() 3645 3646#endif 3647 3648DEFHEADING(Linux/Multiboot boot specific:) 3649SRST 3650When using these options, you can use a given Linux or Multiboot kernel 3651without installing it in the disk image. It can be useful for easier 3652testing of various kernels. 3653 3654 3655ERST 3656 3657DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3658 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3659SRST 3660``-kernel bzImage`` 3661 Use bzImage as kernel image. The kernel can be either a Linux kernel 3662 or in multiboot format. 3663ERST 3664 3665DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3666 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3667SRST 3668``-append cmdline`` 3669 Use cmdline as kernel command line 3670ERST 3671 3672DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3673 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3674SRST 3675``-initrd file`` 3676 Use file as initial ram disk. 3677 3678``-initrd "file1 arg=foo,file2"`` 3679 This syntax is only available with multiboot. 3680 3681 Use file1 and file2 as modules and pass arg=foo as parameter to the 3682 first module. 3683ERST 3684 3685DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3686 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3687SRST 3688``-dtb file`` 3689 Use file as a device tree binary (dtb) image and pass it to the 3690 kernel on boot. 3691ERST 3692 3693DEFHEADING() 3694 3695DEFHEADING(Debug/Expert options:) 3696 3697DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3698 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3699 " Policy for handling deprecated management interfaces\n" 3700 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3701 " Policy for handling unstable management interfaces\n", 3702 QEMU_ARCH_ALL) 3703SRST 3704``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3705 Set policy for handling deprecated management interfaces (experimental): 3706 3707 ``deprecated-input=accept`` (default) 3708 Accept deprecated commands and arguments 3709 ``deprecated-input=reject`` 3710 Reject deprecated commands and arguments 3711 ``deprecated-input=crash`` 3712 Crash on deprecated commands and arguments 3713 ``deprecated-output=accept`` (default) 3714 Emit deprecated command results and events 3715 ``deprecated-output=hide`` 3716 Suppress deprecated command results and events 3717 3718 Limitation: covers only syntactic aspects of QMP. 3719 3720``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3721 Set policy for handling unstable management interfaces (experimental): 3722 3723 ``unstable-input=accept`` (default) 3724 Accept unstable commands and arguments 3725 ``unstable-input=reject`` 3726 Reject unstable commands and arguments 3727 ``unstable-input=crash`` 3728 Crash on unstable commands and arguments 3729 ``unstable-output=accept`` (default) 3730 Emit unstable command results and events 3731 ``unstable-output=hide`` 3732 Suppress unstable command results and events 3733 3734 Limitation: covers only syntactic aspects of QMP. 3735ERST 3736 3737DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3738 "-fw_cfg [name=]<name>,file=<file>\n" 3739 " add named fw_cfg entry with contents from file\n" 3740 "-fw_cfg [name=]<name>,string=<str>\n" 3741 " add named fw_cfg entry with contents from string\n", 3742 QEMU_ARCH_ALL) 3743SRST 3744``-fw_cfg [name=]name,file=file`` 3745 Add named fw\_cfg entry with contents from file file. 3746 3747``-fw_cfg [name=]name,string=str`` 3748 Add named fw\_cfg entry with contents from string str. 3749 3750 The terminating NUL character of the contents of str will not be 3751 included as part of the fw\_cfg item data. To insert contents with 3752 embedded NUL characters, you have to use the file parameter. 3753 3754 The fw\_cfg entries are passed by QEMU through to the guest. 3755 3756 Example: 3757 3758 :: 3759 3760 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3761 3762 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3763 from ./my\_blob.bin. 3764ERST 3765 3766DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3767 "-serial dev redirect the serial port to char device 'dev'\n", 3768 QEMU_ARCH_ALL) 3769SRST 3770``-serial dev`` 3771 Redirect the virtual serial port to host character device dev. The 3772 default device is ``vc`` in graphical mode and ``stdio`` in non 3773 graphical mode. 3774 3775 This option can be used several times to simulate up to 4 serial 3776 ports. 3777 3778 Use ``-serial none`` to disable all serial ports. 3779 3780 Available character devices are: 3781 3782 ``vc[:WxH]`` 3783 Virtual console. Optionally, a width and height can be given in 3784 pixel with 3785 3786 :: 3787 3788 vc:800x600 3789 3790 It is also possible to specify width or height in characters: 3791 3792 :: 3793 3794 vc:80Cx24C 3795 3796 ``pty`` 3797 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3798 3799 ``none`` 3800 No device is allocated. 3801 3802 ``null`` 3803 void device 3804 3805 ``chardev:id`` 3806 Use a named character device defined with the ``-chardev`` 3807 option. 3808 3809 ``/dev/XXX`` 3810 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3811 port parameters are set according to the emulated ones. 3812 3813 ``/dev/parportN`` 3814 [Linux only, parallel port only] Use host parallel port N. 3815 Currently SPP and EPP parallel port features can be used. 3816 3817 ``file:filename`` 3818 Write output to filename. No character can be read. 3819 3820 ``stdio`` 3821 [Unix only] standard input/output 3822 3823 ``pipe:filename`` 3824 name pipe filename 3825 3826 ``COMn`` 3827 [Windows only] Use host serial port n 3828 3829 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3830 This implements UDP Net Console. When remote\_host or src\_ip 3831 are not specified they default to ``0.0.0.0``. When not using a 3832 specified src\_port a random port is automatically chosen. 3833 3834 If you just want a simple readonly console you can use 3835 ``netcat`` or ``nc``, by starting QEMU with: 3836 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3837 QEMU writes something to that port it will appear in the 3838 netconsole session. 3839 3840 If you plan to send characters back via netconsole or you want 3841 to stop and start QEMU a lot of times, you should have QEMU use 3842 the same source port each time by using something like ``-serial 3843 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3844 version of netcat which can listen to a TCP port and send and 3845 receive characters via udp. If you have a patched version of 3846 netcat which activates telnet remote echo and single char 3847 transfer, then you can use the following options to set up a 3848 netcat redirector to allow telnet on port 5555 to access the 3849 QEMU port. 3850 3851 ``QEMU Options:`` 3852 -serial udp::4555@:4556 3853 3854 ``netcat options:`` 3855 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3856 3857 ``telnet options:`` 3858 localhost 5555 3859 3860 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3861 The TCP Net Console has two modes of operation. It can send the 3862 serial I/O to a location or wait for a connection from a 3863 location. By default the TCP Net Console is sent to host at the 3864 port. If you use the ``server=on`` option QEMU will wait for a client 3865 socket application to connect to the port before continuing, 3866 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3867 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3868 option only applies if ``server=no`` is set, if the connection goes 3869 down it will attempt to reconnect at the given interval. If host 3870 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3871 time is accepted. You can use ``telnet=on`` to connect to the 3872 corresponding character device. 3873 3874 ``Example to send tcp console to 192.168.0.2 port 4444`` 3875 -serial tcp:192.168.0.2:4444 3876 3877 ``Example to listen and wait on port 4444 for connection`` 3878 -serial tcp::4444,server=on 3879 3880 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3881 -serial tcp:192.168.0.100:4444,server=on,wait=off 3882 3883 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3884 The telnet protocol is used instead of raw tcp sockets. The 3885 options work the same as if you had specified ``-serial tcp``. 3886 The difference is that the port acts like a telnet server or 3887 client using telnet option negotiation. This will also allow you 3888 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3889 supports sending the break sequence. Typically in unix telnet 3890 you do it with Control-] and then type "send break" followed by 3891 pressing the enter key. 3892 3893 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3894 The WebSocket protocol is used instead of raw tcp socket. The 3895 port acts as a WebSocket server. Client mode is not supported. 3896 3897 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3898 A unix domain socket is used instead of a tcp socket. The option 3899 works the same as if you had specified ``-serial tcp`` except 3900 the unix domain socket path is used for connections. 3901 3902 ``mon:dev_string`` 3903 This is a special option to allow the monitor to be multiplexed 3904 onto another serial port. The monitor is accessed with key 3905 sequence of Control-a and then pressing c. dev\_string should be 3906 any one of the serial devices specified above. An example to 3907 multiplex the monitor onto a telnet server listening on port 3908 4444 would be: 3909 3910 ``-serial mon:telnet::4444,server=on,wait=off`` 3911 3912 When the monitor is multiplexed to stdio in this way, Ctrl+C 3913 will not terminate QEMU any more but will be passed to the guest 3914 instead. 3915 3916 ``braille`` 3917 Braille device. This will use BrlAPI to display the braille 3918 output on a real or fake device. 3919 3920 ``msmouse`` 3921 Three button serial mouse. Configure the guest to use Microsoft 3922 protocol. 3923ERST 3924 3925DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3926 "-parallel dev redirect the parallel port to char device 'dev'\n", 3927 QEMU_ARCH_ALL) 3928SRST 3929``-parallel dev`` 3930 Redirect the virtual parallel port to host device dev (same devices 3931 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3932 to use hardware devices connected on the corresponding host parallel 3933 port. 3934 3935 This option can be used several times to simulate up to 3 parallel 3936 ports. 3937 3938 Use ``-parallel none`` to disable all parallel ports. 3939ERST 3940 3941DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3942 "-monitor dev redirect the monitor to char device 'dev'\n", 3943 QEMU_ARCH_ALL) 3944SRST 3945``-monitor dev`` 3946 Redirect the monitor to host device dev (same devices as the serial 3947 port). The default device is ``vc`` in graphical mode and ``stdio`` 3948 in non graphical mode. Use ``-monitor none`` to disable the default 3949 monitor. 3950ERST 3951DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3952 "-qmp dev like -monitor but opens in 'control' mode\n", 3953 QEMU_ARCH_ALL) 3954SRST 3955``-qmp dev`` 3956 Like -monitor but opens in 'control' mode. 3957ERST 3958DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3959 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3960 QEMU_ARCH_ALL) 3961SRST 3962``-qmp-pretty dev`` 3963 Like -qmp but uses pretty JSON formatting. 3964ERST 3965 3966DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3967 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3968SRST 3969``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3970 Setup monitor on chardev name. ``mode=control`` configures 3971 a QMP monitor (a JSON RPC-style protocol) and it is not the 3972 same as HMP, the human monitor that has a "(qemu)" prompt. 3973 ``pretty`` is only valid when ``mode=control``, 3974 turning on JSON pretty printing to ease 3975 human reading and debugging. 3976ERST 3977 3978DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3979 "-debugcon dev redirect the debug console to char device 'dev'\n", 3980 QEMU_ARCH_ALL) 3981SRST 3982``-debugcon dev`` 3983 Redirect the debug console to host device dev (same devices as the 3984 serial port). The debug console is an I/O port which is typically 3985 port 0xe9; writing to that I/O port sends output to this device. The 3986 default device is ``vc`` in graphical mode and ``stdio`` in non 3987 graphical mode. 3988ERST 3989 3990DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3991 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3992SRST 3993``-pidfile file`` 3994 Store the QEMU process PID in file. It is useful if you launch QEMU 3995 from a script. 3996ERST 3997 3998DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3999 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4000SRST 4001``-singlestep`` 4002 Run the emulation in single step mode. 4003ERST 4004 4005DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4006 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4007 QEMU_ARCH_ALL) 4008SRST 4009``--preconfig`` 4010 Pause QEMU for interactive configuration before the machine is 4011 created, which allows querying and configuring properties that will 4012 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4013 exit the preconfig state and move to the next state (i.e. run guest 4014 if -S isn't used or pause the second time if -S is used). This 4015 option is experimental. 4016ERST 4017 4018DEF("S", 0, QEMU_OPTION_S, \ 4019 "-S freeze CPU at startup (use 'c' to start execution)\n", 4020 QEMU_ARCH_ALL) 4021SRST 4022``-S`` 4023 Do not start CPU at startup (you must type 'c' in the monitor). 4024ERST 4025 4026DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4027 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4028 " run qemu with overcommit hints\n" 4029 " mem-lock=on|off controls memory lock support (default: off)\n" 4030 " cpu-pm=on|off controls cpu power management (default: off)\n", 4031 QEMU_ARCH_ALL) 4032SRST 4033``-overcommit mem-lock=on|off`` 4034 \ 4035``-overcommit cpu-pm=on|off`` 4036 Run qemu with hints about host resource overcommit. The default is 4037 to assume that host overcommits all resources. 4038 4039 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4040 (disabled by default). This works when host memory is not 4041 overcommitted and reduces the worst-case latency for guest. 4042 4043 Guest ability to manage power state of host cpus (increasing latency 4044 for other processes on the same host cpu, but decreasing latency for 4045 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4046 works best when host CPU is not overcommitted. When used, host 4047 estimates of CPU cycle and power utilization will be incorrect, not 4048 taking into account guest idle time. 4049ERST 4050 4051DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4052 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4053 " the guest without waiting for gdb to connect; use -S too\n" 4054 " if you want it to not start execution.)\n", 4055 QEMU_ARCH_ALL) 4056SRST 4057``-gdb dev`` 4058 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4059 in the System Emulation Users Guide). Note that this option does not pause QEMU 4060 execution -- if you want QEMU to not start the guest until you 4061 connect with gdb and issue a ``continue`` command, you will need to 4062 also pass the ``-S`` option to QEMU. 4063 4064 The most usual configuration is to listen on a local TCP socket:: 4065 4066 -gdb tcp::3117 4067 4068 but you can specify other backends; UDP, pseudo TTY, or even stdio 4069 are all reasonable use cases. For example, a stdio connection 4070 allows you to start QEMU from within gdb and establish the 4071 connection via a pipe: 4072 4073 .. parsed-literal:: 4074 4075 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4076ERST 4077 4078DEF("s", 0, QEMU_OPTION_s, \ 4079 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4080 QEMU_ARCH_ALL) 4081SRST 4082``-s`` 4083 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4084 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4085ERST 4086 4087DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4088 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4089 QEMU_ARCH_ALL) 4090SRST 4091``-d item1[,...]`` 4092 Enable logging of specified items. Use '-d help' for a list of log 4093 items. 4094ERST 4095 4096DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4097 "-D logfile output log to logfile (default stderr)\n", 4098 QEMU_ARCH_ALL) 4099SRST 4100``-D logfile`` 4101 Output log in logfile instead of to stderr 4102ERST 4103 4104DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4105 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4106 QEMU_ARCH_ALL) 4107SRST 4108``-dfilter range1[,...]`` 4109 Filter debug output to that relevant to a range of target addresses. 4110 The filter spec can be either start+size, start-size or start..end 4111 where start end and size are the addresses and sizes required. For 4112 example: 4113 4114 :: 4115 4116 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4117 4118 Will dump output for any code in the 0x1000 sized block starting at 4119 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4120 another 0x1000 sized block starting at 0xffffffc00005f000. 4121ERST 4122 4123DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4124 "-seed number seed the pseudo-random number generator\n", 4125 QEMU_ARCH_ALL) 4126SRST 4127``-seed number`` 4128 Force the guest to use a deterministic pseudo-random number 4129 generator, seeded with number. This does not affect crypto routines 4130 within the host. 4131ERST 4132 4133DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4134 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4135 QEMU_ARCH_ALL) 4136SRST 4137``-L path`` 4138 Set the directory for the BIOS, VGA BIOS and keymaps. 4139 4140 To list all the data directories, use ``-L help``. 4141ERST 4142 4143DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4144 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4145SRST 4146``-bios file`` 4147 Set the filename for the BIOS. 4148ERST 4149 4150DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4151 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 4152SRST 4153``-enable-kvm`` 4154 Enable KVM full virtualization support. This option is only 4155 available if KVM support is enabled when compiling. 4156ERST 4157 4158DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4159 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 4160DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4161 "-xen-attach attach to existing xen domain\n" 4162 " libxl will use this when starting QEMU\n", 4163 QEMU_ARCH_ALL) 4164DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4165 "-xen-domid-restrict restrict set of available xen operations\n" 4166 " to specified domain id. (Does not affect\n" 4167 " xenpv machine type).\n", 4168 QEMU_ARCH_ALL) 4169SRST 4170``-xen-domid id`` 4171 Specify xen guest domain id (XEN only). 4172 4173``-xen-attach`` 4174 Attach to existing xen domain. libxl will use this when starting 4175 QEMU (XEN only). Restrict set of available xen operations to 4176 specified domain id (XEN only). 4177ERST 4178 4179DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4180 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4181SRST 4182``-no-reboot`` 4183 Exit instead of rebooting. 4184ERST 4185 4186DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4187 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4188SRST 4189``-no-shutdown`` 4190 Don't exit QEMU on guest shutdown, but instead only stop the 4191 emulation. This allows for instance switching to monitor to commit 4192 changes to the disk image. 4193ERST 4194 4195DEF("action", HAS_ARG, QEMU_OPTION_action, 4196 "-action reboot=reset|shutdown\n" 4197 " action when guest reboots [default=reset]\n" 4198 "-action shutdown=poweroff|pause\n" 4199 " action when guest shuts down [default=poweroff]\n" 4200 "-action panic=pause|shutdown|none\n" 4201 " action when guest panics [default=shutdown]\n" 4202 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4203 " action when watchdog fires [default=reset]\n", 4204 QEMU_ARCH_ALL) 4205SRST 4206``-action event=action`` 4207 The action parameter serves to modify QEMU's default behavior when 4208 certain guest events occur. It provides a generic method for specifying the 4209 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4210 parameters. 4211 4212 Examples: 4213 4214 ``-action panic=none`` 4215 ``-action reboot=shutdown,shutdown=pause`` 4216 ``-watchdog i6300esb -action watchdog=pause`` 4217 4218ERST 4219 4220DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4221 "-loadvm [tag|id]\n" \ 4222 " start right away with a saved state (loadvm in monitor)\n", 4223 QEMU_ARCH_ALL) 4224SRST 4225``-loadvm file`` 4226 Start right away with a saved state (``loadvm`` in monitor) 4227ERST 4228 4229#ifndef _WIN32 4230DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4231 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4232#endif 4233SRST 4234``-daemonize`` 4235 Daemonize the QEMU process after initialization. QEMU will not 4236 detach from standard IO until it is ready to receive connections on 4237 any of its devices. This option is a useful way for external 4238 programs to launch QEMU without having to cope with initialization 4239 race conditions. 4240ERST 4241 4242DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4243 "-option-rom rom load a file, rom, into the option ROM space\n", 4244 QEMU_ARCH_ALL) 4245SRST 4246``-option-rom file`` 4247 Load the contents of file as an option ROM. This option is useful to 4248 load things like EtherBoot. 4249ERST 4250 4251DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4252 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4253 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4254 QEMU_ARCH_ALL) 4255 4256SRST 4257``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4258 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4259 the current UTC or local time, respectively. ``localtime`` is 4260 required for correct date in MS-DOS or Windows. To start at a 4261 specific point in time, provide datetime in the format 4262 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4263 4264 By default the RTC is driven by the host system time. This allows 4265 using of the RTC as accurate reference clock inside the guest, 4266 specifically if the host time is smoothly following an accurate 4267 external reference clock, e.g. via NTP. If you want to isolate the 4268 guest time from the host, you can set ``clock`` to ``rt`` instead, 4269 which provides a host monotonic clock if host support it. To even 4270 prevent the RTC from progressing during suspension, you can set 4271 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4272 recommended especially in icount mode in order to preserve 4273 determinism; however, note that in icount mode the speed of the 4274 virtual clock is variable and can in general differ from the host 4275 clock. 4276 4277 Enable ``driftfix`` (i386 targets only) if you experience time drift 4278 problems, specifically with Windows' ACPI HAL. This option will try 4279 to figure out how many timer interrupts were not processed by the 4280 Windows guest and will re-inject them. 4281ERST 4282 4283DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4284 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4285 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4286 " instruction, enable aligning the host and virtual clocks\n" \ 4287 " or disable real time cpu sleeping, and optionally enable\n" \ 4288 " record-and-replay mode\n", QEMU_ARCH_ALL) 4289SRST 4290``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4291 Enable virtual instruction counter. The virtual cpu will execute one 4292 instruction every 2^N ns of virtual time. If ``auto`` is specified 4293 then the virtual cpu speed will be automatically adjusted to keep 4294 virtual time within a few seconds of real time. 4295 4296 Note that while this option can give deterministic behavior, it does 4297 not provide cycle accurate emulation. Modern CPUs contain 4298 superscalar out of order cores with complex cache hierarchies. The 4299 number of instructions executed often has little or no correlation 4300 with actual performance. 4301 4302 When the virtual cpu is sleeping, the virtual time will advance at 4303 default speed unless ``sleep=on`` is specified. With 4304 ``sleep=on``, the virtual time will jump to the next timer 4305 deadline instantly whenever the virtual cpu goes to sleep mode and 4306 will not advance if no timer is enabled. This behavior gives 4307 deterministic execution times from the guest point of view. 4308 The default if icount is enabled is ``sleep=off``. 4309 ``sleep=on`` cannot be used together with either ``shift=auto`` 4310 or ``align=on``. 4311 4312 ``align=on`` will activate the delay algorithm which will try to 4313 synchronise the host clock and the virtual clock. The goal is to 4314 have a guest running at the real frequency imposed by the shift 4315 option. Whenever the guest clock is behind the host clock and if 4316 ``align=on`` is specified then we print a message to the user to 4317 inform about the delay. Currently this option does not work when 4318 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4319 shift values for which the guest clock runs ahead of the host clock. 4320 Typically this happens when the shift value is high (how high 4321 depends on the host machine). The default if icount is enabled 4322 is ``align=off``. 4323 4324 When the ``rr`` option is specified deterministic record/replay is 4325 enabled. The ``rrfile=`` option must also be provided to 4326 specify the path to the replay log. In record mode data is written 4327 to this file, and in replay mode it is read back. 4328 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4329 name. In record mode, a new VM snapshot with the given name is created 4330 at the start of execution recording. In replay mode this option 4331 specifies the snapshot name used to load the initial VM state. 4332ERST 4333 4334DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4335 "-watchdog model\n" \ 4336 " enable virtual hardware watchdog [default=none]\n", 4337 QEMU_ARCH_ALL) 4338SRST 4339``-watchdog model`` 4340 Create a virtual hardware watchdog device. Once enabled (by a guest 4341 action), the watchdog must be periodically polled by an agent inside 4342 the guest or else the guest will be restarted. Choose a model for 4343 which your guest has drivers. 4344 4345 The model is the model of hardware watchdog to emulate. Use 4346 ``-watchdog help`` to list available hardware models. Only one 4347 watchdog can be enabled for a guest. 4348 4349 The following models may be available: 4350 4351 ``ib700`` 4352 iBASE 700 is a very simple ISA watchdog with a single timer. 4353 4354 ``i6300esb`` 4355 Intel 6300ESB I/O controller hub is a much more featureful 4356 PCI-based dual-timer watchdog. 4357 4358 ``diag288`` 4359 A virtual watchdog for s390x backed by the diagnose 288 4360 hypercall (currently KVM only). 4361ERST 4362 4363DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4364 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4365 " action when watchdog fires [default=reset]\n", 4366 QEMU_ARCH_ALL) 4367SRST 4368``-watchdog-action action`` 4369 The action controls what QEMU will do when the watchdog timer 4370 expires. The default is ``reset`` (forcefully reset the guest). 4371 Other possible actions are: ``shutdown`` (attempt to gracefully 4372 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4373 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4374 guest), ``debug`` (print a debug message and continue), or ``none`` 4375 (do nothing). 4376 4377 Note that the ``shutdown`` action requires that the guest responds 4378 to ACPI signals, which it may not be able to do in the sort of 4379 situations where the watchdog would have expired, and thus 4380 ``-watchdog-action shutdown`` is not recommended for production use. 4381 4382 Examples: 4383 4384 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4385 4386ERST 4387 4388DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4389 "-echr chr set terminal escape character instead of ctrl-a\n", 4390 QEMU_ARCH_ALL) 4391SRST 4392``-echr numeric_ascii_value`` 4393 Change the escape character used for switching to the monitor when 4394 using monitor and serial sharing. The default is ``0x01`` when using 4395 the ``-nographic`` option. ``0x01`` is equal to pressing 4396 ``Control-a``. You can select a different character from the ascii 4397 control keys where 1 through 26 map to Control-a through Control-z. 4398 For instance you could use the either of the following to change the 4399 escape character to Control-t. 4400 4401 ``-echr 0x14``; \ ``-echr 20`` 4402 4403ERST 4404 4405DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4406 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4407 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4408 "-incoming unix:socketpath\n" \ 4409 " prepare for incoming migration, listen on\n" \ 4410 " specified protocol and socket address\n" \ 4411 "-incoming fd:fd\n" \ 4412 "-incoming exec:cmdline\n" \ 4413 " accept incoming migration on given file descriptor\n" \ 4414 " or from given external command\n" \ 4415 "-incoming defer\n" \ 4416 " wait for the URI to be specified via migrate_incoming\n", 4417 QEMU_ARCH_ALL) 4418SRST 4419``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4420 \ 4421``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4422 Prepare for incoming migration, listen on a given tcp port. 4423 4424``-incoming unix:socketpath`` 4425 Prepare for incoming migration, listen on a given unix socket. 4426 4427``-incoming fd:fd`` 4428 Accept incoming migration from a given filedescriptor. 4429 4430``-incoming exec:cmdline`` 4431 Accept incoming migration as an output from specified external 4432 command. 4433 4434``-incoming defer`` 4435 Wait for the URI to be specified via migrate\_incoming. The monitor 4436 can be used to change settings (such as migration parameters) prior 4437 to issuing the migrate\_incoming to allow the migration to begin. 4438ERST 4439 4440DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4441 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4442SRST 4443``-only-migratable`` 4444 Only allow migratable devices. Devices will not be allowed to enter 4445 an unmigratable state. 4446ERST 4447 4448DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4449 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4450SRST 4451``-nodefaults`` 4452 Don't create default devices. Normally, QEMU sets the default 4453 devices like serial port, parallel port, virtual console, monitor 4454 device, VGA adapter, floppy and CD-ROM drive and others. The 4455 ``-nodefaults`` option will disable all those default devices. 4456ERST 4457 4458#ifndef _WIN32 4459DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4460 "-chroot dir chroot to dir just before starting the VM\n", 4461 QEMU_ARCH_ALL) 4462#endif 4463SRST 4464``-chroot dir`` 4465 Immediately before starting guest execution, chroot to the specified 4466 directory. Especially useful in combination with -runas. 4467ERST 4468 4469#ifndef _WIN32 4470DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4471 "-runas user change to user id user just before starting the VM\n" \ 4472 " user can be numeric uid:gid instead\n", 4473 QEMU_ARCH_ALL) 4474#endif 4475SRST 4476``-runas user`` 4477 Immediately before starting guest execution, drop root privileges, 4478 switching to the specified user. 4479ERST 4480 4481DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4482 "-prom-env variable=value\n" 4483 " set OpenBIOS nvram variables\n", 4484 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4485SRST 4486``-prom-env variable=value`` 4487 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4488 4489 :: 4490 4491 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4492 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4493 4494 :: 4495 4496 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4497 -prom-env 'boot-device=hd:2,\yaboot' \ 4498 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4499ERST 4500DEF("semihosting", 0, QEMU_OPTION_semihosting, 4501 "-semihosting semihosting mode\n", 4502 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4503 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4504SRST 4505``-semihosting`` 4506 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4507 4508 Note that this allows guest direct access to the host filesystem, so 4509 should only be used with a trusted guest OS. 4510 4511 See the -semihosting-config option documentation for further 4512 information about the facilities this enables. 4513ERST 4514DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4515 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4516 " semihosting configuration\n", 4517QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4518QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4519SRST 4520``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4521 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4522 only). 4523 4524 Note that this allows guest direct access to the host filesystem, so 4525 should only be used with a trusted guest OS. 4526 4527 On Arm this implements the standard semihosting API, version 2.0. 4528 4529 On M68K this implements the "ColdFire GDB" interface used by 4530 libgloss. 4531 4532 Xtensa semihosting provides basic file IO calls, such as 4533 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4534 linux platform "sim" use this interface. 4535 4536 On RISC-V this implements the standard semihosting API, version 0.2. 4537 4538 ``target=native|gdb|auto`` 4539 Defines where the semihosting calls will be addressed, to QEMU 4540 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4541 means ``gdb`` during debug sessions and ``native`` otherwise. 4542 4543 ``chardev=str1`` 4544 Send the output to a chardev backend output for native or auto 4545 output when not in gdb 4546 4547 ``arg=str1,arg=str2,...`` 4548 Allows the user to pass input arguments, and can be used 4549 multiple times to build up a list. The old-style 4550 ``-kernel``/``-append`` method of passing a command line is 4551 still supported for backward compatibility. If both the 4552 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4553 specified, the former is passed to semihosting as it always 4554 takes precedence. 4555ERST 4556DEF("old-param", 0, QEMU_OPTION_old_param, 4557 "-old-param old param mode\n", QEMU_ARCH_ARM) 4558SRST 4559``-old-param`` 4560 Old param mode (ARM only). 4561ERST 4562 4563DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4564 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4565 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4566 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4567 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4568 " by the kernel, but typically no longer used by modern\n" \ 4569 " C library implementations.\n" \ 4570 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4571 " to elevate privileges using set*uid|gid system calls.\n" \ 4572 " The value 'children' will deny set*uid|gid system calls for\n" \ 4573 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4574 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4575 " blocking *fork and execve\n" \ 4576 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4577 QEMU_ARCH_ALL) 4578SRST 4579``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4580 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4581 filtering and 'off' will disable it. The default is 'off'. 4582 4583 ``obsolete=string`` 4584 Enable Obsolete system calls 4585 4586 ``elevateprivileges=string`` 4587 Disable set\*uid\|gid system calls 4588 4589 ``spawn=string`` 4590 Disable \*fork and execve 4591 4592 ``resourcecontrol=string`` 4593 Disable process affinity and schedular priority 4594ERST 4595 4596DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4597 "-readconfig <file>\n", QEMU_ARCH_ALL) 4598SRST 4599``-readconfig file`` 4600 Read device configuration from file. This approach is useful when 4601 you want to spawn QEMU process with many command line options but 4602 you don't want to exceed the command line character limit. 4603ERST 4604DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4605 "-writeconfig <file>\n" 4606 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4607SRST 4608ERST 4609 4610DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4611 "-no-user-config\n" 4612 " do not load default user-provided config files at startup\n", 4613 QEMU_ARCH_ALL) 4614SRST 4615``-no-user-config`` 4616 The ``-no-user-config`` option makes QEMU not load any of the 4617 user-provided config files on sysconfdir. 4618ERST 4619 4620DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4621 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4622 " specify tracing options\n", 4623 QEMU_ARCH_ALL) 4624SRST 4625``-trace [[enable=]pattern][,events=file][,file=file]`` 4626 .. include:: ../qemu-option-trace.rst.inc 4627 4628ERST 4629DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4630 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4631 " load a plugin\n", 4632 QEMU_ARCH_ALL) 4633SRST 4634``-plugin file=file[,argname=argvalue]`` 4635 Load a plugin. 4636 4637 ``file=file`` 4638 Load the given plugin from a shared library file. 4639 4640 ``argname=argvalue`` 4641 Argument passed to the plugin. (Can be given multiple times.) 4642ERST 4643 4644HXCOMM Internal use 4645DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4646DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4647 4648#ifdef __linux__ 4649DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4650 "-enable-fips enable FIPS 140-2 compliance\n", 4651 QEMU_ARCH_ALL) 4652#endif 4653SRST 4654``-enable-fips`` 4655 Enable FIPS 140-2 compliance mode. 4656ERST 4657 4658DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4659 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4660 " control error message format\n" 4661 " timestamp=on enables timestamps (default: off)\n" 4662 " guest-name=on enables guest name prefix but only if\n" 4663 " -name guest option is set (default: off)\n", 4664 QEMU_ARCH_ALL) 4665SRST 4666``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4667 Control error message format. 4668 4669 ``timestamp=on|off`` 4670 Prefix messages with a timestamp. Default is off. 4671 4672 ``guest-name=on|off`` 4673 Prefix messages with guest name but only if -name guest option is set 4674 otherwise the option is ignored. Default is off. 4675ERST 4676 4677DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4678 "-dump-vmstate <file>\n" 4679 " Output vmstate information in JSON format to file.\n" 4680 " Use the scripts/vmstate-static-checker.py file to\n" 4681 " check for possible regressions in migration code\n" 4682 " by comparing two such vmstate dumps.\n", 4683 QEMU_ARCH_ALL) 4684SRST 4685``-dump-vmstate file`` 4686 Dump json-encoded vmstate information for current machine type to 4687 file in file 4688ERST 4689 4690DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4691 "-enable-sync-profile\n" 4692 " enable synchronization profiling\n", 4693 QEMU_ARCH_ALL) 4694SRST 4695``-enable-sync-profile`` 4696 Enable synchronization profiling. 4697ERST 4698 4699DEFHEADING() 4700 4701DEFHEADING(Generic object creation:) 4702 4703DEF("object", HAS_ARG, QEMU_OPTION_object, 4704 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4705 " create a new object of type TYPENAME setting properties\n" 4706 " in the order they are specified. Note that the 'id'\n" 4707 " property must be set. These objects are placed in the\n" 4708 " '/objects' path.\n", 4709 QEMU_ARCH_ALL) 4710SRST 4711``-object typename[,prop1=value1,...]`` 4712 Create a new object of type typename setting properties in the order 4713 they are specified. Note that the 'id' property must be set. These 4714 objects are placed in the '/objects' path. 4715 4716 ``-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`` 4717 Creates a memory file backend object, which can be used to back 4718 the guest RAM with huge pages. 4719 4720 The ``id`` parameter is a unique ID that will be used to 4721 reference this memory region in other parameters, e.g. ``-numa``, 4722 ``-device nvdimm``, etc. 4723 4724 The ``size`` option provides the size of the memory region, and 4725 accepts common suffixes, e.g. ``500M``. 4726 4727 The ``mem-path`` provides the path to either a shared memory or 4728 huge page filesystem mount. 4729 4730 The ``share`` boolean option determines whether the memory 4731 region is marked as private to QEMU, or shared. The latter 4732 allows a co-operating external process to access the QEMU memory 4733 region. 4734 4735 The ``share`` is also required for pvrdma devices due to 4736 limitations in the RDMA API provided by Linux. 4737 4738 Setting share=on might affect the ability to configure NUMA 4739 bindings for the memory backend under some circumstances, see 4740 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4741 source tree for additional details. 4742 4743 Setting the ``discard-data`` boolean option to on indicates that 4744 file contents can be destroyed when QEMU exits, to avoid 4745 unnecessarily flushing data to the backing file. Note that 4746 ``discard-data`` is only an optimization, and QEMU might not 4747 discard file contents if it aborts unexpectedly or is terminated 4748 using SIGKILL. 4749 4750 The ``merge`` boolean option enables memory merge, also known as 4751 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4752 the pages for memory deduplication. 4753 4754 Setting the ``dump`` boolean option to off excludes the memory 4755 from core dumps. This feature is also known as MADV\_DONTDUMP. 4756 4757 The ``prealloc`` boolean option enables memory preallocation. 4758 4759 The ``host-nodes`` option binds the memory range to a list of 4760 NUMA host nodes. 4761 4762 The ``policy`` option sets the NUMA policy to one of the 4763 following values: 4764 4765 ``default`` 4766 default host policy 4767 4768 ``preferred`` 4769 prefer the given host node list for allocation 4770 4771 ``bind`` 4772 restrict memory allocation to the given host node list 4773 4774 ``interleave`` 4775 interleave memory allocations across the given host node 4776 list 4777 4778 The ``align`` option specifies the base address alignment when 4779 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4780 ``2M``. Some backend store specified by ``mem-path`` requires an 4781 alignment different than the default one used by QEMU, eg the 4782 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4783 such cases, users can specify the required alignment via this 4784 option. 4785 4786 The ``pmem`` option specifies whether the backing file specified 4787 by ``mem-path`` is in host persistent memory that can be 4788 accessed using the SNIA NVM programming model (e.g. Intel 4789 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4790 operations to guarantee the persistence of its own writes to 4791 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4792 migration). Also, we will map the backend-file with MAP\_SYNC 4793 flag, which ensures the file metadata is in sync for 4794 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4795 requires support from both the host kernel (since Linux kernel 4796 4.15) and the filesystem of ``mem-path`` mounted with DAX 4797 option. 4798 4799 The ``readonly`` option specifies whether the backing file is opened 4800 read-only or read-write (default). 4801 4802 ``-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`` 4803 Creates a memory backend object, which can be used to back the 4804 guest RAM. Memory backend objects offer more control than the 4805 ``-m`` option that is traditionally used to define guest RAM. 4806 Please refer to ``memory-backend-file`` for a description of the 4807 options. 4808 4809 ``-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`` 4810 Creates an anonymous memory file backend object, which allows 4811 QEMU to share the memory with an external process (e.g. when 4812 using vhost-user). The memory is allocated with memfd and 4813 optional sealing. (Linux only) 4814 4815 The ``seal`` option creates a sealed-file, that will block 4816 further resizing the memory ('on' by default). 4817 4818 The ``hugetlb`` option specify the file to be created resides in 4819 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4820 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4821 the hugetlb page size on systems that support multiple hugetlb 4822 page sizes (it must be a power of 2 value supported by the 4823 system). 4824 4825 In some versions of Linux, the ``hugetlb`` option is 4826 incompatible with the ``seal`` option (requires at least Linux 4827 4.16). 4828 4829 Please refer to ``memory-backend-file`` for a description of the 4830 other options. 4831 4832 The ``share`` boolean option is on by default with memfd. 4833 4834 ``-object rng-builtin,id=id`` 4835 Creates a random number generator backend which obtains entropy 4836 from QEMU builtin functions. The ``id`` parameter is a unique ID 4837 that will be used to reference this entropy backend from the 4838 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4839 uses this RNG backend. 4840 4841 ``-object rng-random,id=id,filename=/dev/random`` 4842 Creates a random number generator backend which obtains entropy 4843 from a device on the host. The ``id`` parameter is a unique ID 4844 that will be used to reference this entropy backend from the 4845 ``virtio-rng`` device. The ``filename`` parameter specifies 4846 which file to obtain entropy from and if omitted defaults to 4847 ``/dev/urandom``. 4848 4849 ``-object rng-egd,id=id,chardev=chardevid`` 4850 Creates a random number generator backend which obtains entropy 4851 from an external daemon running on the host. The ``id`` 4852 parameter is a unique ID that will be used to reference this 4853 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4854 parameter is the unique ID of a character device backend that 4855 provides the connection to the RNG daemon. 4856 4857 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4858 Creates a TLS anonymous credentials object, which can be used to 4859 provide TLS support on network backends. The ``id`` parameter is 4860 a unique ID which network backends will use to access the 4861 credentials. The ``endpoint`` is either ``server`` or ``client`` 4862 depending on whether the QEMU network backend that uses the 4863 credentials will be acting as a client or as a server. If 4864 ``verify-peer`` is enabled (the default) then once the handshake 4865 is completed, the peer credentials will be verified, though this 4866 is a no-op for anonymous credentials. 4867 4868 The dir parameter tells QEMU where to find the credential files. 4869 For server endpoints, this directory may contain a file 4870 dh-params.pem providing diffie-hellman parameters to use for the 4871 TLS server. If the file is missing, QEMU will generate a set of 4872 DH parameters at startup. This is a computationally expensive 4873 operation that consumes random pool entropy, so it is 4874 recommended that a persistent set of parameters be generated 4875 upfront and saved. 4876 4877 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4878 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4879 can be used to provide TLS support on network backends. The 4880 ``id`` parameter is a unique ID which network backends will use 4881 to access the credentials. The ``endpoint`` is either ``server`` 4882 or ``client`` depending on whether the QEMU network backend that 4883 uses the credentials will be acting as a client or as a server. 4884 For clients only, ``username`` is the username which will be 4885 sent to the server. If omitted it defaults to "qemu". 4886 4887 The dir parameter tells QEMU where to find the keys file. It is 4888 called "dir/keys.psk" and contains "username:key" pairs. This 4889 file can most easily be created using the GnuTLS ``psktool`` 4890 program. 4891 4892 For server endpoints, dir may also contain a file dh-params.pem 4893 providing diffie-hellman parameters to use for the TLS server. 4894 If the file is missing, QEMU will generate a set of DH 4895 parameters at startup. This is a computationally expensive 4896 operation that consumes random pool entropy, so it is 4897 recommended that a persistent set of parameters be generated up 4898 front and saved. 4899 4900 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4901 Creates a TLS anonymous credentials object, which can be used to 4902 provide TLS support on network backends. The ``id`` parameter is 4903 a unique ID which network backends will use to access the 4904 credentials. The ``endpoint`` is either ``server`` or ``client`` 4905 depending on whether the QEMU network backend that uses the 4906 credentials will be acting as a client or as a server. If 4907 ``verify-peer`` is enabled (the default) then once the handshake 4908 is completed, the peer credentials will be verified. With x509 4909 certificates, this implies that the clients must be provided 4910 with valid client certificates too. 4911 4912 The dir parameter tells QEMU where to find the credential files. 4913 For server endpoints, this directory may contain a file 4914 dh-params.pem providing diffie-hellman parameters to use for the 4915 TLS server. If the file is missing, QEMU will generate a set of 4916 DH parameters at startup. This is a computationally expensive 4917 operation that consumes random pool entropy, so it is 4918 recommended that a persistent set of parameters be generated 4919 upfront and saved. 4920 4921 For x509 certificate credentials the directory will contain 4922 further files providing the x509 certificates. The certificates 4923 must be stored in PEM format, in filenames ca-cert.pem, 4924 ca-crl.pem (optional), server-cert.pem (only servers), 4925 server-key.pem (only servers), client-cert.pem (only clients), 4926 and client-key.pem (only clients). 4927 4928 For the server-key.pem and client-key.pem files which contain 4929 sensitive private keys, it is possible to use an encrypted 4930 version by providing the passwordid parameter. This provides the 4931 ID of a previously created ``secret`` object containing the 4932 password for decryption. 4933 4934 The priority parameter allows to override the global default 4935 priority used by gnutls. This can be useful if the system 4936 administrator needs to use a weaker set of crypto priorities for 4937 QEMU without potentially forcing the weakness onto all 4938 applications. Or conversely if one wants wants a stronger 4939 default for QEMU than for all other applications, they can do 4940 this through this parameter. Its format is a gnutls priority 4941 string as described at 4942 https://gnutls.org/manual/html_node/Priority-Strings.html. 4943 4944 ``-object tls-cipher-suites,id=id,priority=priority`` 4945 Creates a TLS cipher suites object, which can be used to control 4946 the TLS cipher/protocol algorithms that applications are permitted 4947 to use. 4948 4949 The ``id`` parameter is a unique ID which frontends will use to 4950 access the ordered list of permitted TLS cipher suites from the 4951 host. 4952 4953 The ``priority`` parameter allows to override the global default 4954 priority used by gnutls. This can be useful if the system 4955 administrator needs to use a weaker set of crypto priorities for 4956 QEMU without potentially forcing the weakness onto all 4957 applications. Or conversely if one wants wants a stronger 4958 default for QEMU than for all other applications, they can do 4959 this through this parameter. Its format is a gnutls priority 4960 string as described at 4961 https://gnutls.org/manual/html_node/Priority-Strings.html. 4962 4963 An example of use of this object is to control UEFI HTTPS Boot. 4964 The tls-cipher-suites object exposes the ordered list of permitted 4965 TLS cipher suites from the host side to the guest firmware, via 4966 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4967 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4968 guest-side TLS. 4969 4970 In the following example, the priority at which the host-side policy 4971 is retrieved is given by the ``priority`` property. 4972 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4973 refer to /etc/crypto-policies/back-ends/gnutls.config. 4974 4975 .. parsed-literal:: 4976 4977 # |qemu_system| \\ 4978 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4979 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4980 4981 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4982 Interval t can't be 0, this filter batches the packet delivery: 4983 all packets arriving in a given interval on netdev netdevid are 4984 delayed until the end of the interval. Interval is in 4985 microseconds. ``status`` is optional that indicate whether the 4986 netfilter is on (enabled) or off (disabled), the default status 4987 for netfilter will be 'on'. 4988 4989 queue all\|rx\|tx is an option that can be applied to any 4990 netfilter. 4991 4992 ``all``: the filter is attached both to the receive and the 4993 transmit queue of the netdev (default). 4994 4995 ``rx``: the filter is attached to the receive queue of the 4996 netdev, where it will receive packets sent to the netdev. 4997 4998 ``tx``: the filter is attached to the transmit queue of the 4999 netdev, where it will receive packets sent by the netdev. 5000 5001 position head\|tail\|id=<id> is an option to specify where the 5002 filter should be inserted in the filter list. It can be applied 5003 to any netfilter. 5004 5005 ``head``: the filter is inserted at the head of the filter list, 5006 before any existing filters. 5007 5008 ``tail``: the filter is inserted at the tail of the filter list, 5009 behind any existing filters (default). 5010 5011 ``id=<id>``: the filter is inserted before or behind the filter 5012 specified by <id>, see the insert option below. 5013 5014 insert behind\|before is an option to specify where to insert 5015 the new filter relative to the one specified with 5016 position=id=<id>. It can be applied to any netfilter. 5017 5018 ``before``: insert before the specified filter. 5019 5020 ``behind``: insert behind the specified filter (default). 5021 5022 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5023 filter-mirror on netdev netdevid,mirror net packet to 5024 chardevchardevid, if it has the vnet\_hdr\_support flag, 5025 filter-mirror will mirror packet with vnet\_hdr\_len. 5026 5027 ``-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]`` 5028 filter-redirector on netdev netdevid,redirect filter's net 5029 packet to chardev chardevid,and redirect indev's packet to 5030 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5031 will redirect packet with vnet\_hdr\_len. Create a 5032 filter-redirector we need to differ outdev id from indev id, id 5033 can not be the same. we can just use indev or outdev, but at 5034 least one of indev or outdev need to be specified. 5035 5036 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5037 Filter-rewriter is a part of COLO project.It will rewrite tcp 5038 packet to secondary from primary to keep secondary tcp 5039 connection,and rewrite tcp packet to primary from secondary make 5040 tcp packet can be handled by client.if it has the 5041 vnet\_hdr\_support flag, we can parse packet with vnet header. 5042 5043 usage: colo secondary: -object 5044 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5045 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5046 filter-rewriter,id=rew0,netdev=hn0,queue=all 5047 5048 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5049 Dump the network traffic on netdev dev to the file specified by 5050 filename. At most len bytes (64k by default) per packet are 5051 stored. The file format is libpcap, so it can be analyzed with 5052 tools such as tcpdump or Wireshark. 5053 5054 ``-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}]`` 5055 Colo-compare gets packet from primary\_in chardevid and 5056 secondary\_in, then compare whether the payload of primary packet 5057 and secondary packet are the same. If same, it will output 5058 primary packet to out\_dev, else it will notify COLO-framework to do 5059 checkpoint and send primary packet to out\_dev. In order to 5060 improve efficiency, we need to put the task of comparison in 5061 another iothread. If it has the vnet\_hdr\_support flag, 5062 colo compare will send/recv packet with vnet\_hdr\_len. 5063 The compare\_timeout=@var{ms} determines the maximum time of the 5064 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5065 is to set the period of scanning expired primary node network packets. 5066 The max\_queue\_size=@var{size} is to set the max compare queue 5067 size depend on user environment. 5068 If user want to use Xen COLO, need to add the notify\_dev to 5069 notify Xen colo-frame to do checkpoint. 5070 5071 COLO-compare must be used with the help of filter-mirror, 5072 filter-redirector and filter-rewriter. 5073 5074 :: 5075 5076 KVM COLO 5077 5078 primary: 5079 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5080 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5081 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5082 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5083 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5084 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5085 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5086 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5087 -object iothread,id=iothread1 5088 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5089 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5090 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5091 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5092 5093 secondary: 5094 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5095 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5096 -chardev socket,id=red0,host=3.3.3.3,port=9003 5097 -chardev socket,id=red1,host=3.3.3.3,port=9004 5098 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5099 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5100 5101 5102 Xen COLO 5103 5104 primary: 5105 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5106 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5107 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5108 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5109 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5110 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5111 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5112 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5113 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5114 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5115 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5116 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5117 -object iothread,id=iothread1 5118 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5119 5120 secondary: 5121 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5122 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5123 -chardev socket,id=red0,host=3.3.3.3,port=9003 5124 -chardev socket,id=red1,host=3.3.3.3,port=9004 5125 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5126 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5127 5128 If you want to know the detail of above command line, you can 5129 read the colo-compare git log. 5130 5131 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5132 Creates a cryptodev backend which executes crypto opreation from 5133 the QEMU cipher APIS. The id parameter is a unique ID that will 5134 be used to reference this cryptodev backend from the 5135 ``virtio-crypto`` device. The queues parameter is optional, 5136 which specify the queue number of cryptodev backend, the default 5137 of queues is 1. 5138 5139 .. parsed-literal:: 5140 5141 # |qemu_system| \\ 5142 [...] \\ 5143 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5144 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5145 [...] 5146 5147 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5148 Creates a vhost-user cryptodev backend, backed by a chardev 5149 chardevid. The id parameter is a unique ID that will be used to 5150 reference this cryptodev backend from the ``virtio-crypto`` 5151 device. The chardev should be a unix domain socket backed one. 5152 The vhost-user uses a specifically defined protocol to pass 5153 vhost ioctl replacement messages to an application on the other 5154 end of the socket. The queues parameter is optional, which 5155 specify the queue number of cryptodev backend for multiqueue 5156 vhost-user, the default of queues is 1. 5157 5158 .. parsed-literal:: 5159 5160 # |qemu_system| \\ 5161 [...] \\ 5162 -chardev socket,id=chardev0,path=/path/to/socket \\ 5163 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5164 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5165 [...] 5166 5167 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5168 \ 5169 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5170 Defines a secret to store a password, encryption key, or some 5171 other sensitive data. The sensitive data can either be passed 5172 directly via the data parameter, or indirectly via the file 5173 parameter. Using the data parameter is insecure unless the 5174 sensitive data is encrypted. 5175 5176 The sensitive data can be provided in raw format (the default), 5177 or base64. When encoded as JSON, the raw format only supports 5178 valid UTF-8 characters, so base64 is recommended for sending 5179 binary data. QEMU will convert from which ever format is 5180 provided to the format it needs internally. eg, an RBD password 5181 can be provided in raw format, even though it will be base64 5182 encoded when passed onto the RBD sever. 5183 5184 For added protection, it is possible to encrypt the data 5185 associated with a secret using the AES-256-CBC cipher. Use of 5186 encryption is indicated by providing the keyid and iv 5187 parameters. The keyid parameter provides the ID of a previously 5188 defined secret that contains the AES-256 decryption key. This 5189 key should be 32-bytes long and be base64 encoded. The iv 5190 parameter provides the random initialization vector used for 5191 encryption of this particular secret and should be a base64 5192 encrypted string of the 16-byte IV. 5193 5194 The simplest (insecure) usage is to provide the secret inline 5195 5196 .. parsed-literal:: 5197 5198 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5199 5200 The simplest secure usage is to provide the secret via a file 5201 5202 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5203 secret,id=sec0,file=mypasswd.txt,format=raw 5204 5205 For greater security, AES-256-CBC should be used. To illustrate 5206 usage, consider the openssl command line tool which can encrypt 5207 the data. Note that when encrypting, the plaintext must be 5208 padded to the cipher block size (32 bytes) using the standard 5209 PKCS#5/6 compatible padding algorithm. 5210 5211 First a master key needs to be created in base64 encoding: 5212 5213 :: 5214 5215 # openssl rand -base64 32 > key.b64 5216 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5217 5218 Each secret to be encrypted needs to have a random 5219 initialization vector generated. These do not need to be kept 5220 secret 5221 5222 :: 5223 5224 # openssl rand -base64 16 > iv.b64 5225 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5226 5227 The secret to be defined can now be encrypted, in this case 5228 we're telling openssl to base64 encode the result, but it could 5229 be left as raw bytes if desired. 5230 5231 :: 5232 5233 # SECRET=$(printf "letmein" | 5234 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5235 5236 When launching QEMU, create a master secret pointing to 5237 ``key.b64`` and specify that to be used to decrypt the user 5238 password. Pass the contents of ``iv.b64`` to the second secret 5239 5240 .. parsed-literal:: 5241 5242 # |qemu_system| \\ 5243 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5244 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5245 data=$SECRET,iv=$(<iv.b64) 5246 5247 ``-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]`` 5248 Create a Secure Encrypted Virtualization (SEV) guest object, 5249 which can be used to provide the guest memory encryption support 5250 on AMD processors. 5251 5252 When memory encryption is enabled, one of the physical address 5253 bit (aka the C-bit) is utilized to mark if a memory page is 5254 protected. The ``cbitpos`` is used to provide the C-bit 5255 position. The C-bit position is Host family dependent hence user 5256 must provide this value. On EPYC, the value should be 47. 5257 5258 When memory encryption is enabled, we loose certain bits in 5259 physical address space. The ``reduced-phys-bits`` is used to 5260 provide the number of bits we loose in physical address space. 5261 Similar to C-bit, the value is Host family dependent. On EPYC, 5262 the value should be 5. 5263 5264 The ``sev-device`` provides the device file to use for 5265 communicating with the SEV firmware running inside AMD Secure 5266 Processor. The default device is '/dev/sev'. If hardware 5267 supports memory encryption then /dev/sev devices are created by 5268 CCP driver. 5269 5270 The ``policy`` provides the guest policy to be enforced by the 5271 SEV firmware and restrict what configuration and operational 5272 commands can be performed on this guest by the hypervisor. The 5273 policy should be provided by the guest owner and is bound to the 5274 guest and cannot be changed throughout the lifetime of the 5275 guest. The default is 0. 5276 5277 If guest ``policy`` allows sharing the key with another SEV 5278 guest then ``handle`` can be use to provide handle of the guest 5279 from which to share the key. 5280 5281 The ``dh-cert-file`` and ``session-file`` provides the guest 5282 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5283 and session parameters are used for establishing a cryptographic 5284 session with the guest owner to negotiate keys used for 5285 attestation. The file must be encoded in base64. 5286 5287 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5288 cmdline to a designated guest firmware page for measured Linux 5289 boot with -kernel. The default is off. (Since 6.2) 5290 5291 e.g to launch a SEV guest 5292 5293 .. parsed-literal:: 5294 5295 # |qemu_system_x86| \\ 5296 ...... \\ 5297 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5298 -machine ...,memory-encryption=sev0 \\ 5299 ..... 5300 5301 ``-object authz-simple,id=id,identity=string`` 5302 Create an authorization object that will control access to 5303 network services. 5304 5305 The ``identity`` parameter is identifies the user and its format 5306 depends on the network service that authorization object is 5307 associated with. For authorizing based on TLS x509 certificates, 5308 the identity must be the x509 distinguished name. Note that care 5309 must be taken to escape any commas in the distinguished name. 5310 5311 An example authorization object to validate a x509 distinguished 5312 name would look like: 5313 5314 .. parsed-literal:: 5315 5316 # |qemu_system| \\ 5317 ... \\ 5318 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5319 ... 5320 5321 Note the use of quotes due to the x509 distinguished name 5322 containing whitespace, and escaping of ','. 5323 5324 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5325 Create an authorization object that will control access to 5326 network services. 5327 5328 The ``filename`` parameter is the fully qualified path to a file 5329 containing the access control list rules in JSON format. 5330 5331 An example set of rules that match against SASL usernames might 5332 look like: 5333 5334 :: 5335 5336 { 5337 "rules": [ 5338 { "match": "fred", "policy": "allow", "format": "exact" }, 5339 { "match": "bob", "policy": "allow", "format": "exact" }, 5340 { "match": "danb", "policy": "deny", "format": "glob" }, 5341 { "match": "dan*", "policy": "allow", "format": "exact" }, 5342 ], 5343 "policy": "deny" 5344 } 5345 5346 When checking access the object will iterate over all the rules 5347 and the first rule to match will have its ``policy`` value 5348 returned as the result. If no rules match, then the default 5349 ``policy`` value is returned. 5350 5351 The rules can either be an exact string match, or they can use 5352 the simple UNIX glob pattern matching to allow wildcards to be 5353 used. 5354 5355 If ``refresh`` is set to true the file will be monitored and 5356 automatically reloaded whenever its content changes. 5357 5358 As with the ``authz-simple`` object, the format of the identity 5359 strings being matched depends on the network service, but is 5360 usually a TLS x509 distinguished name, or a SASL username. 5361 5362 An example authorization object to validate a SASL username 5363 would look like: 5364 5365 .. parsed-literal:: 5366 5367 # |qemu_system| \\ 5368 ... \\ 5369 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5370 ... 5371 5372 ``-object authz-pam,id=id,service=string`` 5373 Create an authorization object that will control access to 5374 network services. 5375 5376 The ``service`` parameter provides the name of a PAM service to 5377 use for authorization. It requires that a file 5378 ``/etc/pam.d/service`` exist to provide the configuration for 5379 the ``account`` subsystem. 5380 5381 An example authorization object to validate a TLS x509 5382 distinguished name would look like: 5383 5384 .. parsed-literal:: 5385 5386 # |qemu_system| \\ 5387 ... \\ 5388 -object authz-pam,id=auth0,service=qemu-vnc \\ 5389 ... 5390 5391 There would then be a corresponding config file for PAM at 5392 ``/etc/pam.d/qemu-vnc`` that contains: 5393 5394 :: 5395 5396 account requisite pam_listfile.so item=user sense=allow \ 5397 file=/etc/qemu/vnc.allow 5398 5399 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5400 of x509 distingished names that are permitted access 5401 5402 :: 5403 5404 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5405 5406 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5407 Creates a dedicated event loop thread that devices can be 5408 assigned to. This is known as an IOThread. By default device 5409 emulation happens in vCPU threads or the main event loop thread. 5410 This can become a scalability bottleneck. IOThreads allow device 5411 emulation and I/O to run on other host CPUs. 5412 5413 The ``id`` parameter is a unique ID that will be used to 5414 reference this IOThread from ``-device ...,iothread=id``. 5415 Multiple devices can be assigned to an IOThread. Note that not 5416 all devices support an ``iothread`` parameter. 5417 5418 The ``query-iothreads`` QMP command lists IOThreads and reports 5419 their thread IDs so that the user can configure host CPU 5420 pinning/affinity. 5421 5422 IOThreads use an adaptive polling algorithm to reduce event loop 5423 latency. Instead of entering a blocking system call to monitor 5424 file descriptors and then pay the cost of being woken up when an 5425 event occurs, the polling algorithm spins waiting for events for 5426 a short time. The algorithm's default parameters are suitable 5427 for many cases but can be adjusted based on knowledge of the 5428 workload and/or host device latency. 5429 5430 The ``poll-max-ns`` parameter is the maximum number of 5431 nanoseconds to busy wait for events. Polling can be disabled by 5432 setting this value to 0. 5433 5434 The ``poll-grow`` parameter is the multiplier used to increase 5435 the polling time when the algorithm detects it is missing events 5436 due to not polling long enough. 5437 5438 The ``poll-shrink`` parameter is the divisor used to decrease 5439 the polling time when the algorithm detects it is spending too 5440 long polling without encountering events. 5441 5442 The ``aio-max-batch`` parameter is the maximum number of requests 5443 in a batch for the AIO engine, 0 means that the engine will use 5444 its default. 5445 5446 The IOThread parameters can be modified at run-time using the 5447 ``qom-set`` command (where ``iothread1`` is the IOThread's 5448 ``id``): 5449 5450 :: 5451 5452 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5453ERST 5454 5455 5456HXCOMM This is the last statement. Insert new options before this line! 5457 5458#undef DEF 5459#undef DEFHEADING 5460#undef ARCHHEADING 5461
