1HXCOMM See docs/devel/docs.rst for the format of this file. 2HXCOMM 3HXCOMM Use DEFHEADING() to define headings in both help text and rST. 4HXCOMM Text between SRST and ERST is copied to the rST version and 5HXCOMM discarded from C version. 6HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 7HXCOMM construct option structures, enums and help message for specified 8HXCOMM architectures. 9HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 10 11DEFHEADING(Standard options:) 12 13DEF("help", 0, QEMU_OPTION_h, 14 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 15SRST 16``-h`` 17 Display help and exit 18ERST 19 20DEF("version", 0, QEMU_OPTION_version, 21 "-version display version information and exit\n", QEMU_ARCH_ALL) 22SRST 23``-version`` 24 Display version information and exit 25ERST 26 27DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 28 "-machine [type=]name[,prop[=value][,...]]\n" 29 " selects emulated machine ('-machine help' for list)\n" 30 " property accel=accel1[:accel2[:...]] selects accelerator\n" 31 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 32 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 33 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 34 " mem-merge=on|off controls memory merge support (default: on)\n" 35 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 36 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 37 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 38 " nvdimm=on|off controls NVDIMM support (default=off)\n" 39 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 40 " hmat=on|off controls ACPI HMAT support (default=off)\n" 41 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 42 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 43 QEMU_ARCH_ALL) 44SRST 45``-machine [type=]name[,prop=value[,...]]`` 46 Select the emulated machine by name. Use ``-machine help`` to list 47 available machines. 48 49 For architectures which aim to support live migration compatibility 50 across releases, each release will introduce a new versioned machine 51 type. For example, the 2.8.0 release introduced machine types 52 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 53 54 To allow live migration of guests from QEMU version 2.8.0, to QEMU 55 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 56 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 57 skip multiple intermediate releases when upgrading, new releases of 58 QEMU will support machine types from many previous versions. 59 60 Supported machine properties are: 61 62 ``accel=accels1[:accels2[:...]]`` 63 This is used to enable an accelerator. Depending on the target 64 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 65 By default, tcg is used. If there is more than one accelerator 66 specified, the next one is used if the previous one fails to 67 initialize. 68 69 ``vmport=on|off|auto`` 70 Enables emulation of VMWare IO port, for vmmouse etc. auto says 71 to select the value based on accel. For accel=xen the default is 72 off otherwise the default is on. 73 74 ``dump-guest-core=on|off`` 75 Include guest memory in a core dump. The default is on. 76 77 ``mem-merge=on|off`` 78 Enables or disables memory merge support. This feature, when 79 supported by the host, de-duplicates identical memory pages 80 among VMs instances (enabled by default). 81 82 ``aes-key-wrap=on|off`` 83 Enables or disables AES key wrapping support on s390-ccw hosts. 84 This feature controls whether AES wrapping keys will be created 85 to allow execution of AES cryptographic functions. The default 86 is on. 87 88 ``dea-key-wrap=on|off`` 89 Enables or disables DEA key wrapping support on s390-ccw hosts. 90 This feature controls whether DEA wrapping keys will be created 91 to allow execution of DEA cryptographic functions. The default 92 is on. 93 94 ``nvdimm=on|off`` 95 Enables or disables NVDIMM support. The default is off. 96 97 ``memory-encryption=`` 98 Memory encryption object to use. The default is none. 99 100 ``hmat=on|off`` 101 Enables or disables ACPI Heterogeneous Memory Attribute Table 102 (HMAT) support. The default is off. 103 104 ``memory-backend='id'`` 105 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 106 Allows to use a memory backend as main RAM. 107 108 For example: 109 :: 110 111 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 112 -machine memory-backend=pc.ram 113 -m 512M 114 115 Migration compatibility note: 116 117 * as backend id one shall use value of 'default-ram-id', advertised by 118 machine type (available via ``query-machines`` QMP command), if migration 119 to/from old QEMU (<5.0) is expected. 120 * for machine types 4.0 and older, user shall 121 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 122 if migration to/from old QEMU (<5.0) is expected. 123 124 For example: 125 :: 126 127 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 128 -machine memory-backend=pc.ram 129 -m 512M 130 131 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 132 Define a CXL Fixed Memory Window (CFMW). 133 134 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 135 136 They are regions of Host Physical Addresses (HPA) on a system which 137 may be interleaved across one or more CXL host bridges. The system 138 software will assign particular devices into these windows and 139 configure the downstream Host-managed Device Memory (HDM) decoders 140 in root ports, switch ports and devices appropriately to meet the 141 interleave requirements before enabling the memory devices. 142 143 ``targets.X=target`` provides the mapping to CXL host bridges 144 which may be identified by the id provided in the -device entry. 145 Multiple entries are needed to specify all the targets when 146 the fixed memory window represents interleaved memory. X is the 147 target index from 0. 148 149 ``size=size`` sets the size of the CFMW. This must be a multiple of 150 256MiB. The region will be aligned to 256MiB but the location is 151 platform and configuration dependent. 152 153 ``interleave-granularity=granularity`` sets the granularity of 154 interleave. Default 256 (bytes). Only 256, 512, 1k, 2k, 155 4k, 8k and 16k granularities supported. 156 157 Example: 158 159 :: 160 161 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512 162ERST 163 164DEF("M", HAS_ARG, QEMU_OPTION_M, 165 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 166 QEMU_ARCH_ALL) 167 168SRST 169``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 170 Define an SGX EPC section. 171ERST 172 173DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 174 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 175SRST 176``-cpu model`` 177 Select CPU model (``-cpu help`` for list and additional feature 178 selection) 179ERST 180 181DEF("accel", HAS_ARG, QEMU_OPTION_accel, 182 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 183 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 184 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 185 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 186 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 187 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 188 " split-wx=on|off (enable TCG split w^x mapping)\n" 189 " tb-size=n (TCG translation block cache size)\n" 190 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 191 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 192 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 193 " thread=single|multi (enable multi-threaded TCG)\n" 194 " device=path (KVM device path, default /dev/kvm)\n", QEMU_ARCH_ALL) 195SRST 196``-accel name[,prop=value[,...]]`` 197 This is used to enable an accelerator. Depending on the target 198 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 199 default, tcg is used. If there is more than one accelerator 200 specified, the next one is used if the previous one fails to 201 initialize. 202 203 ``igd-passthru=on|off`` 204 When Xen is in use, this option controls whether Intel 205 integrated graphics devices can be passed through to the guest 206 (default=off) 207 208 ``kernel-irqchip=on|off|split`` 209 Controls KVM in-kernel irqchip support. The default is full 210 acceleration of the interrupt controllers. On x86, split irqchip 211 reduces the kernel attack surface, at a performance cost for 212 non-MSI interrupts. Disabling the in-kernel irqchip completely 213 is not recommended except for debugging purposes. 214 215 ``kvm-shadow-mem=size`` 216 Defines the size of the KVM shadow MMU. 217 218 ``one-insn-per-tb=on|off`` 219 Makes the TCG accelerator put only one guest instruction into 220 each translation block. This slows down emulation a lot, but 221 can be useful in some situations, such as when trying to analyse 222 the logs produced by the ``-d`` option. 223 224 ``split-wx=on|off`` 225 Controls the use of split w^x mapping for the TCG code generation 226 buffer. Some operating systems require this to be enabled, and in 227 such a case this will default on. On other operating systems, this 228 will default off, but one may enable this for testing or debugging. 229 230 ``tb-size=n`` 231 Controls the size (in MiB) of the TCG translation block cache. 232 233 ``thread=single|multi`` 234 Controls number of TCG threads. When the TCG is multi-threaded 235 there will be one thread per vCPU therefore taking advantage of 236 additional host cores. The default is to enable multi-threading 237 where both the back-end and front-ends support it and no 238 incompatible TCG features have been enabled (e.g. 239 icount/replay). 240 241 ``dirty-ring-size=n`` 242 When the KVM accelerator is used, it controls the size of the per-vCPU 243 dirty page ring buffer (number of entries for each vCPU). It should 244 be a value that is power of two, and it should be 1024 or bigger (but 245 still less than the maximum value that the kernel supports). 4096 246 could be a good initial value if you have no idea which is the best. 247 Set this value to 0 to disable the feature. By default, this feature 248 is disabled (dirty-ring-size=0). When enabled, KVM will instead 249 record dirty pages in a bitmap. 250 251 ``eager-split-size=n`` 252 KVM implements dirty page logging at the PAGE_SIZE granularity and 253 enabling dirty-logging on a huge-page requires breaking it into 254 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 255 lazily by default. There are performance benefits in doing huge-page 256 split eagerly, especially in situations where TLBI costs associated 257 with break-before-make sequences are considerable and also if guest 258 workloads are read intensive. The size here specifies how many pages 259 to break at a time and needs to be a valid block size which is 260 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 261 respectively. Be wary of specifying a higher size as it will have an 262 impact on the memory. By default, this feature is disabled 263 (eager-split-size=0). 264 265 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 266 Enables or disables notify VM exit support on x86 host and specify 267 the corresponding notify window to trigger the VM exit if enabled. 268 ``run`` option enables the feature. It does nothing and continue 269 if the exit happens. ``internal-error`` option enables the feature. 270 It raises a internal error. ``disable`` option doesn't enable the feature. 271 This feature can mitigate the CPU stuck issue due to event windows don't 272 open up for a specified of time (i.e. notify-window). 273 Default: notify-vmexit=run,notify-window=0. 274 275 ``device=path`` 276 Sets the path to the KVM device node. Defaults to ``/dev/kvm``. This 277 option can be used to pass the KVM device to use via a file descriptor 278 by setting the value to ``/dev/fdset/NN``. 279 280ERST 281 282DEF("smp", HAS_ARG, QEMU_OPTION_smp, 283 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 284 " [,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 285 " set the number of initial CPUs to 'n' [default=1]\n" 286 " maxcpus= maximum number of total CPUs, including\n" 287 " offline CPUs for hotplug, etc\n" 288 " drawers= number of drawers on the machine board\n" 289 " books= number of books in one drawer\n" 290 " sockets= number of sockets in one book\n" 291 " dies= number of dies in one socket\n" 292 " clusters= number of clusters in one die\n" 293 " cores= number of cores in one cluster\n" 294 " threads= number of threads in one core\n" 295 "Note: Different machines may have different subsets of the CPU topology\n" 296 " parameters supported, so the actual meaning of the supported parameters\n" 297 " will vary accordingly. For example, for a machine type that supports a\n" 298 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 299 " sequentially mean as below:\n" 300 " sockets means the number of sockets on the machine board\n" 301 " cores means the number of cores in one socket\n" 302 " threads means the number of threads in one core\n" 303 " For a particular machine type board, an expected CPU topology hierarchy\n" 304 " can be defined through the supported sub-option. Unsupported parameters\n" 305 " can also be provided in addition to the sub-option, but their values\n" 306 " must be set as 1 in the purpose of correct parsing.\n", 307 QEMU_ARCH_ALL) 308SRST 309``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 310 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 311 the machine type board. On boards supporting CPU hotplug, the optional 312 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 313 added at runtime. When both parameters are omitted, the maximum number 314 of CPUs will be calculated from the provided topology members and the 315 initial CPU count will match the maximum number. When only one of them 316 is given then the omitted one will be set to its counterpart's value. 317 Both parameters may be specified, but the maximum number of CPUs must 318 be equal to or greater than the initial CPU count. Product of the 319 CPU topology hierarchy must be equal to the maximum number of CPUs. 320 Both parameters are subject to an upper limit that is determined by 321 the specific machine type chosen. 322 323 To control reporting of CPU topology information, values of the topology 324 parameters can be specified. Machines may only support a subset of the 325 parameters and different machines may have different subsets supported 326 which vary depending on capacity of the corresponding CPU targets. So 327 for a particular machine type board, an expected topology hierarchy can 328 be defined through the supported sub-option. Unsupported parameters can 329 also be provided in addition to the sub-option, but their values must be 330 set as 1 in the purpose of correct parsing. 331 332 Either the initial CPU count, or at least one of the topology parameters 333 must be specified. The specified parameters must be greater than zero, 334 explicit configuration like "cpus=0" is not allowed. Values for any 335 omitted parameters will be computed from those which are given. 336 337 For example, the following sub-option defines a CPU topology hierarchy 338 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 339 core) for a machine that only supports sockets/cores/threads. 340 Some members of the option can be omitted but their values will be 341 automatically computed: 342 343 :: 344 345 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 346 347 The following sub-option defines a CPU topology hierarchy (2 sockets 348 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 349 per core) for PC machines which support sockets/dies/cores/threads. 350 Some members of the option can be omitted but their values will be 351 automatically computed: 352 353 :: 354 355 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 356 357 The following sub-option defines a CPU topology hierarchy (2 sockets 358 totally on the machine, 2 clusters per socket, 2 cores per cluster, 359 2 threads per core) for ARM virt machines which support sockets/clusters 360 /cores/threads. Some members of the option can be omitted but their values 361 will be automatically computed: 362 363 :: 364 365 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 366 367 Historically preference was given to the coarsest topology parameters 368 when computing missing values (ie sockets preferred over cores, which 369 were preferred over threads), however, this behaviour is considered 370 liable to change. Prior to 6.2 the preference was sockets over cores 371 over threads. Since 6.2 the preference is cores over sockets over threads. 372 373 For example, the following option defines a machine board with 2 sockets 374 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 375 376 :: 377 378 -smp 2 379 380 Note: The cluster topology will only be generated in ACPI and exposed 381 to guest if it's explicitly specified in -smp. 382ERST 383 384DEF("numa", HAS_ARG, QEMU_OPTION_numa, 385 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 386 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 387 "-numa dist,src=source,dst=destination,val=distance\n" 388 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 389 "-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" 390 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 391 QEMU_ARCH_ALL) 392SRST 393``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 394 \ 395``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 396 \ 397``-numa dist,src=source,dst=destination,val=distance`` 398 \ 399``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 400 \ 401``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 402 \ 403``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 404 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 405 distance from a source node to a destination node. Set the ACPI 406 Heterogeneous Memory Attributes for the given nodes. 407 408 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 409 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 410 contiguous range of CPU indexes (or a single VCPU if lastcpu is 411 omitted). A non-contiguous set of VCPUs can be represented by 412 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 413 omitted on all nodes, VCPUs are automatically split between them. 414 415 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 416 NUMA node: 417 418 :: 419 420 -numa node,cpus=0-2,cpus=5 421 422 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 423 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 424 assign CPU objects to a node using topology layout properties of 425 CPU. The set of properties is machine specific, and depends on used 426 machine type/'\ ``smp``\ ' options. It could be queried with 427 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 428 property specifies node to which CPU object will be assigned, it's 429 required for node to be declared with '\ ``node``\ ' option before 430 it's used with '\ ``cpu``\ ' option. 431 432 For example: 433 434 :: 435 436 -M pc \ 437 -smp 1,sockets=2,maxcpus=2 \ 438 -numa node,nodeid=0 -numa node,nodeid=1 \ 439 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 440 441 '\ ``memdev``\ ' option assigns RAM from a given memory backend 442 device to a node. It is recommended to use '\ ``memdev``\ ' option 443 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 444 option provides better performance and more control over the 445 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 446 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 447 448 For compatibility reasons, legacy '\ ``mem``\ ' option is 449 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 450 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 451 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 452 option, and vice versa. 453 454 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 455 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 456 for '\ ``-numa node``\ ' without memory specified was removed. 457 458 '\ ``initiator``\ ' is an additional option that points to an 459 initiator NUMA node that has best performance (the lowest latency or 460 largest bandwidth) to this NUMA node. Note that this option can be 461 set only when the machine property 'hmat' is set to 'on'. 462 463 Following example creates a machine with 2 NUMA nodes, node 0 has 464 CPU. node 1 has only memory, and its initiator is node 0. Note that 465 because node 0 has CPU, by default the initiator of node 0 is itself 466 and must be itself. 467 468 :: 469 470 -machine hmat=on \ 471 -m 2G,slots=2,maxmem=4G \ 472 -object memory-backend-ram,size=1G,id=m0 \ 473 -object memory-backend-ram,size=1G,id=m1 \ 474 -numa node,nodeid=0,memdev=m0 \ 475 -numa node,nodeid=1,memdev=m1,initiator=0 \ 476 -smp 2,sockets=2,maxcpus=2 \ 477 -numa cpu,node-id=0,socket-id=0 \ 478 -numa cpu,node-id=0,socket-id=1 479 480 source and destination are NUMA node IDs. distance is the NUMA 481 distance from source to destination. The distance from a node to 482 itself is always 10. If any pair of nodes is given a distance, then 483 all pairs must be given distances. Although, when distances are only 484 given in one direction for each pair of nodes, then the distances in 485 the opposite directions are assumed to be the same. If, however, an 486 asymmetrical pair of distances is given for even one node pair, then 487 all node pairs must be provided distance values for both directions, 488 even when they are symmetrical. When a node is unreachable from 489 another node, set the pair's distance to 255. 490 491 Note that the -``numa`` option doesn't allocate any of the specified 492 resources, it just assigns existing resources to NUMA nodes. This 493 means that one still has to use the ``-m``, ``-smp`` options to 494 allocate RAM and VCPUs respectively. 495 496 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 497 Information between initiator and target NUMA nodes in ACPI 498 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 499 create memory requests, usually it has one or more processors. 500 Target NUMA node contains addressable memory. 501 502 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 503 the memory hierarchy of the target NUMA node: if hierarchy is 504 'memory', the structure represents the memory performance; if 505 hierarchy is 'first-level\|second-level\|third-level', this 506 structure represents aggregated performance of memory side caches 507 for each domain. type of 'data-type' is type of data represented by 508 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 509 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 510 the target memory; if 'hierarchy' is 511 'first-level\|second-level\|third-level', 'data-type' is 512 'access\|read\|write' hit latency or 'access\|read\|write' hit 513 bandwidth of the target memory side cache. 514 515 lat is latency value in nanoseconds. bw is bandwidth value, the 516 possible value and units are NUM[M\|G\|T], mean that the bandwidth 517 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 518 used suffix). Note that if latency or bandwidth value is 0, means 519 the corresponding latency or bandwidth information is not provided. 520 521 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 522 belongs. size is the size of memory side cache in bytes. level is 523 the cache level described in this structure, note that the cache 524 level 0 should not be used with '\ ``hmat-cache``\ ' option. 525 associativity is the cache associativity, the possible value is 526 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 527 is the write policy. line is the cache Line size in bytes. 528 529 For example, the following options describe 2 NUMA nodes. Node 0 has 530 2 cpus and a ram, node 1 has only a ram. The processors in node 0 531 access memory in node 0 with access-latency 5 nanoseconds, 532 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 533 memory in NUMA node 1 with access-latency 10 nanoseconds, 534 access-bandwidth is 100 MB/s. And for memory side cache information, 535 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 536 policy is write-back, the cache Line size is 8 bytes: 537 538 :: 539 540 -machine hmat=on \ 541 -m 2G \ 542 -object memory-backend-ram,size=1G,id=m0 \ 543 -object memory-backend-ram,size=1G,id=m1 \ 544 -smp 2,sockets=2,maxcpus=2 \ 545 -numa node,nodeid=0,memdev=m0 \ 546 -numa node,nodeid=1,memdev=m1,initiator=0 \ 547 -numa cpu,node-id=0,socket-id=0 \ 548 -numa cpu,node-id=0,socket-id=1 \ 549 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 550 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 551 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 552 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 553 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 554 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 555ERST 556 557DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 558 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 559 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 560SRST 561``-add-fd fd=fd,set=set[,opaque=opaque]`` 562 Add a file descriptor to an fd set. Valid options are: 563 564 ``fd=fd`` 565 This option defines the file descriptor of which a duplicate is 566 added to fd set. The file descriptor cannot be stdin, stdout, or 567 stderr. 568 569 ``set=set`` 570 This option defines the ID of the fd set to add the file 571 descriptor to. 572 573 ``opaque=opaque`` 574 This option defines a free-form string that can be used to 575 describe fd. 576 577 You can open an image using pre-opened file descriptors from an fd 578 set: 579 580 .. parsed-literal:: 581 582 |qemu_system| \\ 583 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 584 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 585 -drive file=/dev/fdset/2,index=0,media=disk 586ERST 587 588DEF("set", HAS_ARG, QEMU_OPTION_set, 589 "-set group.id.arg=value\n" 590 " set <arg> parameter for item <id> of type <group>\n" 591 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 592SRST 593``-set group.id.arg=value`` 594 Set parameter arg for item id of type group 595ERST 596 597DEF("global", HAS_ARG, QEMU_OPTION_global, 598 "-global driver.property=value\n" 599 "-global driver=driver,property=property,value=value\n" 600 " set a global default for a driver property\n", 601 QEMU_ARCH_ALL) 602SRST 603``-global driver.prop=value`` 604 \ 605``-global driver=driver,property=property,value=value`` 606 Set default value of driver's property prop to value, e.g.: 607 608 .. parsed-literal:: 609 610 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 611 612 In particular, you can use this to set driver properties for devices 613 which are created automatically by the machine model. To create a 614 device which is not created automatically and set properties on it, 615 use -``device``. 616 617 -global driver.prop=value is shorthand for -global 618 driver=driver,property=prop,value=value. The longhand syntax works 619 even when driver contains a dot. 620ERST 621 622DEF("boot", HAS_ARG, QEMU_OPTION_boot, 623 "-boot [order=drives][,once=drives][,menu=on|off]\n" 624 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 625 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 626 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 627 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 628 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 629 QEMU_ARCH_ALL) 630SRST 631``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 632 Specify boot order drives as a string of drive letters. Valid drive 633 letters depend on the target architecture. The x86 PC uses: a, b 634 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 635 (Etherboot from network adapter 1-4), hard disk boot is the default. 636 To apply a particular boot order only on the first startup, specify 637 it via ``once``. Note that the ``order`` or ``once`` parameter 638 should not be used together with the ``bootindex`` property of 639 devices, since the firmware implementations normally do not support 640 both at the same time. 641 642 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 643 as firmware/BIOS supports them. The default is non-interactive boot. 644 645 A splash picture could be passed to bios, enabling user to show it 646 as logo, when option splash=sp\_name is given and menu=on, If 647 firmware/BIOS supports them. Currently Seabios for X86 system 648 support it. limitation: The splash file could be a jpeg file or a 649 BMP file in 24 BPP format(true color). The resolution should be 650 supported by the SVGA mode, so the recommended is 320x240, 640x480, 651 800x640. 652 653 A timeout could be passed to bios, guest will pause for rb\_timeout 654 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 655 not reboot, qemu passes '-1' to bios by default. Currently Seabios 656 for X86 system support it. 657 658 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 659 it. This only effects when boot priority is changed by bootindex 660 options. The default is non-strict boot. 661 662 .. parsed-literal:: 663 664 # try to boot from network first, then from hard disk 665 |qemu_system_x86| -boot order=nc 666 # boot from CD-ROM first, switch back to default order after reboot 667 |qemu_system_x86| -boot once=d 668 # boot with a splash picture for 5 seconds. 669 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 670 671 Note: The legacy format '-boot drives' is still supported but its 672 use is discouraged as it may be removed from future versions. 673ERST 674 675DEF("m", HAS_ARG, QEMU_OPTION_m, 676 "-m [size=]megs[,slots=n,maxmem=size]\n" 677 " configure guest RAM\n" 678 " size: initial amount of guest memory\n" 679 " slots: number of hotplug slots (default: none)\n" 680 " maxmem: maximum amount of guest memory (default: none)\n" 681 " Note: Some architectures might enforce a specific granularity\n", 682 QEMU_ARCH_ALL) 683SRST 684``-m [size=]megs[,slots=n,maxmem=size]`` 685 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 686 Optionally, a suffix of "M" or "G" can be used to signify a value in 687 megabytes or gigabytes respectively. Optional pair slots, maxmem 688 could be used to set amount of hotpluggable memory slots and maximum 689 amount of memory. Note that maxmem must be aligned to the page size. 690 691 For example, the following command-line sets the guest startup RAM 692 size to 1GB, creates 3 slots to hotplug additional memory and sets 693 the maximum memory the guest can reach to 4GB: 694 695 .. parsed-literal:: 696 697 |qemu_system| -m 1G,slots=3,maxmem=4G 698 699 If slots and maxmem are not specified, memory hotplug won't be 700 enabled and the guest startup RAM will never increase. 701ERST 702 703DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 704 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 705SRST 706``-mem-path path`` 707 Allocate guest RAM from a temporarily created file in path. 708ERST 709 710DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 711 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 712 QEMU_ARCH_ALL) 713SRST 714``-mem-prealloc`` 715 Preallocate memory when using -mem-path. 716ERST 717 718DEF("k", HAS_ARG, QEMU_OPTION_k, 719 "-k language use keyboard layout (for example 'fr' for French)\n", 720 QEMU_ARCH_ALL) 721SRST 722``-k language`` 723 Use keyboard layout language (for example ``fr`` for French). This 724 option is only needed where it is not easy to get raw PC keycodes 725 (e.g. on Macs, with some X11 servers or with a VNC or curses 726 display). You don't normally need to use it on PC/Linux or 727 PC/Windows hosts. 728 729 The available layouts are: 730 731 :: 732 733 ar de-ch es fo fr-ca hu ja mk no pt-br sv 734 da en-gb et fr fr-ch is lt nl pl ru th 735 de en-us fi fr-be hr it lv nl-be pt sl tr 736 737 The default is ``en-us``. 738ERST 739 740 741DEF("audio", HAS_ARG, QEMU_OPTION_audio, 742 "-audio [driver=]driver[,prop[=value][,...]]\n" 743 " specifies default audio backend when `audiodev` is not\n" 744 " used to create a machine or sound device;" 745 " options are the same as for -audiodev\n" 746 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 747 " specifies the audio backend and device to use;\n" 748 " apart from 'model', options are the same as for -audiodev.\n" 749 " use '-audio model=help' to show possible devices.\n", 750 QEMU_ARCH_ALL) 751SRST 752``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 753 If the ``model`` option is specified, ``-audio`` is a shortcut 754 for configuring both the guest audio hardware and the host audio 755 backend in one go. The guest hardware model can be set with 756 ``model=modelname``. Use ``model=help`` to list the available 757 device types. 758 759 The following two example do exactly the same, to show how ``-audio`` 760 can be used to shorten the command line length: 761 762 .. parsed-literal:: 763 764 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 765 |qemu_system| -audio pa,model=sb16 766 767 If the ``model`` option is not specified, ``-audio`` is used to 768 configure a default audio backend that will be used whenever the 769 ``audiodev`` property is not set on a device or machine. In 770 particular, ``-audio none`` ensures that no audio is produced even 771 for machines that have embedded sound hardware. 772 773 In both cases, the driver option is the same as with the corresponding 774 ``-audiodev`` option below. Use ``driver=help`` to list the available 775 drivers. 776 777ERST 778 779DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 780 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 781 " specifies the audio backend to use\n" 782 " Use ``-audiodev help`` to list the available drivers\n" 783 " id= identifier of the backend\n" 784 " timer-period= timer period in microseconds\n" 785 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 786 " in|out.fixed-settings= use fixed settings for host audio\n" 787 " in|out.frequency= frequency to use with fixed settings\n" 788 " in|out.channels= number of channels to use with fixed settings\n" 789 " in|out.format= sample format to use with fixed settings\n" 790 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 791 " in|out.voices= number of voices to use\n" 792 " in|out.buffer-length= length of buffer in microseconds\n" 793 "-audiodev none,id=id,[,prop[=value][,...]]\n" 794 " dummy driver that discards all output\n" 795#ifdef CONFIG_AUDIO_ALSA 796 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 797 " in|out.dev= name of the audio device to use\n" 798 " in|out.period-length= length of period in microseconds\n" 799 " in|out.try-poll= attempt to use poll mode\n" 800 " threshold= threshold (in microseconds) when playback starts\n" 801#endif 802#ifdef CONFIG_AUDIO_COREAUDIO 803 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 804 " in|out.buffer-count= number of buffers\n" 805#endif 806#ifdef CONFIG_AUDIO_DSOUND 807 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 808 " latency= add extra latency to playback in microseconds\n" 809#endif 810#ifdef CONFIG_AUDIO_OSS 811 "-audiodev oss,id=id[,prop[=value][,...]]\n" 812 " in|out.dev= path of the audio device to use\n" 813 " in|out.buffer-count= number of buffers\n" 814 " in|out.try-poll= attempt to use poll mode\n" 815 " try-mmap= try using memory mapped access\n" 816 " exclusive= open device in exclusive mode\n" 817 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 818#endif 819#ifdef CONFIG_AUDIO_PA 820 "-audiodev pa,id=id[,prop[=value][,...]]\n" 821 " server= PulseAudio server address\n" 822 " in|out.name= source/sink device name\n" 823 " in|out.latency= desired latency in microseconds\n" 824#endif 825#ifdef CONFIG_AUDIO_PIPEWIRE 826 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 827 " in|out.name= source/sink device name\n" 828 " in|out.stream-name= name of pipewire stream\n" 829 " in|out.latency= desired latency in microseconds\n" 830#endif 831#ifdef CONFIG_AUDIO_SDL 832 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 833 " in|out.buffer-count= number of buffers\n" 834#endif 835#ifdef CONFIG_AUDIO_SNDIO 836 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 837#endif 838#ifdef CONFIG_SPICE 839 "-audiodev spice,id=id[,prop[=value][,...]]\n" 840#endif 841#ifdef CONFIG_DBUS_DISPLAY 842 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 843#endif 844 "-audiodev wav,id=id[,prop[=value][,...]]\n" 845 " path= path of wav file to record\n", 846 QEMU_ARCH_ALL) 847SRST 848``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 849 Adds a new audio backend driver identified by id. There are global 850 and driver specific properties. Some values can be set differently 851 for input and output, they're marked with ``in|out.``. You can set 852 the input's property with ``in.prop`` and the output's property with 853 ``out.prop``. For example: 854 855 :: 856 857 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 858 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 859 860 NOTE: parameter validation is known to be incomplete, in many cases 861 specifying an invalid option causes QEMU to print an error message 862 and continue emulation without sound. 863 864 Valid global options are: 865 866 ``id=identifier`` 867 Identifies the audio backend. 868 869 ``timer-period=period`` 870 Sets the timer period used by the audio subsystem in 871 microseconds. Default is 10000 (10 ms). 872 873 ``in|out.mixing-engine=on|off`` 874 Use QEMU's mixing engine to mix all streams inside QEMU and 875 convert audio formats when not supported by the backend. When 876 off, fixed-settings must be off too. Note that disabling this 877 option means that the selected backend must support multiple 878 streams and the audio formats used by the virtual cards, 879 otherwise you'll get no sound. It's not recommended to disable 880 this option unless you want to use 5.1 or 7.1 audio, as mixing 881 engine only supports mono and stereo audio. Default is on. 882 883 ``in|out.fixed-settings=on|off`` 884 Use fixed settings for host audio. When off, it will change 885 based on how the guest opens the sound card. In this case you 886 must not specify frequency, channels or format. Default is on. 887 888 ``in|out.frequency=frequency`` 889 Specify the frequency to use when using fixed-settings. Default 890 is 44100Hz. 891 892 ``in|out.channels=channels`` 893 Specify the number of channels to use when using fixed-settings. 894 Default is 2 (stereo). 895 896 ``in|out.format=format`` 897 Specify the sample format to use when using fixed-settings. 898 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 899 ``u32``, ``f32``. Default is ``s16``. 900 901 ``in|out.voices=voices`` 902 Specify the number of voices to use. Default is 1. 903 904 ``in|out.buffer-length=usecs`` 905 Sets the size of the buffer in microseconds. 906 907``-audiodev none,id=id[,prop[=value][,...]]`` 908 Creates a dummy backend that discards all outputs. This backend has 909 no backend specific properties. 910 911``-audiodev alsa,id=id[,prop[=value][,...]]`` 912 Creates backend using the ALSA. This backend is only available on 913 Linux. 914 915 ALSA specific options are: 916 917 ``in|out.dev=device`` 918 Specify the ALSA device to use for input and/or output. Default 919 is ``default``. 920 921 ``in|out.period-length=usecs`` 922 Sets the period length in microseconds. 923 924 ``in|out.try-poll=on|off`` 925 Attempt to use poll mode with the device. Default is on. 926 927 ``threshold=threshold`` 928 Threshold (in microseconds) when playback starts. Default is 0. 929 930``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 931 Creates a backend using Apple's Core Audio. This backend is only 932 available on Mac OS and only supports playback. 933 934 Core Audio specific options are: 935 936 ``in|out.buffer-count=count`` 937 Sets the count of the buffers. 938 939``-audiodev dsound,id=id[,prop[=value][,...]]`` 940 Creates a backend using Microsoft's DirectSound. This backend is 941 only available on Windows and only supports playback. 942 943 DirectSound specific options are: 944 945 ``latency=usecs`` 946 Add extra usecs microseconds latency to playback. Default is 947 10000 (10 ms). 948 949``-audiodev oss,id=id[,prop[=value][,...]]`` 950 Creates a backend using OSS. This backend is available on most 951 Unix-like systems. 952 953 OSS specific options are: 954 955 ``in|out.dev=device`` 956 Specify the file name of the OSS device to use. Default is 957 ``/dev/dsp``. 958 959 ``in|out.buffer-count=count`` 960 Sets the count of the buffers. 961 962 ``in|out.try-poll=on|of`` 963 Attempt to use poll mode with the device. Default is on. 964 965 ``try-mmap=on|off`` 966 Try using memory mapped device access. Default is off. 967 968 ``exclusive=on|off`` 969 Open the device in exclusive mode (vmix won't work in this 970 case). Default is off. 971 972 ``dsp-policy=policy`` 973 Sets the timing policy (between 0 and 10, where smaller number 974 means smaller latency but higher CPU usage). Use -1 to use 975 buffer sizes specified by ``buffer`` and ``buffer-count``. This 976 option is ignored if you do not have OSS 4. Default is 5. 977 978``-audiodev pa,id=id[,prop[=value][,...]]`` 979 Creates a backend using PulseAudio. This backend is available on 980 most systems. 981 982 PulseAudio specific options are: 983 984 ``server=server`` 985 Sets the PulseAudio server to connect to. 986 987 ``in|out.name=sink`` 988 Use the specified source/sink for recording/playback. 989 990 ``in|out.latency=usecs`` 991 Desired latency in microseconds. The PulseAudio server will try 992 to honor this value but actual latencies may be lower or higher. 993 994``-audiodev pipewire,id=id[,prop[=value][,...]]`` 995 Creates a backend using PipeWire. This backend is available on 996 most systems. 997 998 PipeWire specific options are: 999 1000 ``in|out.latency=usecs`` 1001 Desired latency in microseconds. 1002 1003 ``in|out.name=sink`` 1004 Use the specified source/sink for recording/playback. 1005 1006 ``in|out.stream-name`` 1007 Specify the name of pipewire stream. 1008 1009``-audiodev sdl,id=id[,prop[=value][,...]]`` 1010 Creates a backend using SDL. This backend is available on most 1011 systems, but you should use your platform's native backend if 1012 possible. 1013 1014 SDL specific options are: 1015 1016 ``in|out.buffer-count=count`` 1017 Sets the count of the buffers. 1018 1019``-audiodev sndio,id=id[,prop[=value][,...]]`` 1020 Creates a backend using SNDIO. This backend is available on 1021 OpenBSD and most other Unix-like systems. 1022 1023 Sndio specific options are: 1024 1025 ``in|out.dev=device`` 1026 Specify the sndio device to use for input and/or output. Default 1027 is ``default``. 1028 1029 ``in|out.latency=usecs`` 1030 Sets the desired period length in microseconds. 1031 1032``-audiodev spice,id=id[,prop[=value][,...]]`` 1033 Creates a backend that sends audio through SPICE. This backend 1034 requires ``-spice`` and automatically selected in that case, so 1035 usually you can ignore this option. This backend has no backend 1036 specific properties. 1037 1038``-audiodev wav,id=id[,prop[=value][,...]]`` 1039 Creates a backend that writes audio to a WAV file. 1040 1041 Backend specific options are: 1042 1043 ``path=path`` 1044 Write recorded audio into the specified file. Default is 1045 ``qemu.wav``. 1046ERST 1047 1048DEF("device", HAS_ARG, QEMU_OPTION_device, 1049 "-device driver[,prop[=value][,...]]\n" 1050 " add device (based on driver)\n" 1051 " prop=value,... sets driver properties\n" 1052 " use '-device help' to print all possible drivers\n" 1053 " use '-device driver,help' to print all possible properties\n", 1054 QEMU_ARCH_ALL) 1055SRST 1056``-device driver[,prop[=value][,...]]`` 1057 Add device driver. prop=value sets driver properties. Valid 1058 properties depend on the driver. To get help on possible drivers and 1059 properties, use ``-device help`` and ``-device driver,help``. 1060 1061 Some drivers are: 1062 1063``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1064 Add an IPMI BMC. This is a simulation of a hardware management 1065 interface processor that normally sits on a system. It provides a 1066 watchdog and the ability to reset and power control the system. You 1067 need to connect this to an IPMI interface to make it useful 1068 1069 The IPMI slave address to use for the BMC. The default is 0x20. This 1070 address is the BMC's address on the I2C network of management 1071 controllers. If you don't know what this means, it is safe to ignore 1072 it. 1073 1074 ``id=id`` 1075 The BMC id for interfaces to use this device. 1076 1077 ``slave_addr=val`` 1078 Define slave address to use for the BMC. The default is 0x20. 1079 1080 ``sdrfile=file`` 1081 file containing raw Sensor Data Records (SDR) data. The default 1082 is none. 1083 1084 ``fruareasize=val`` 1085 size of a Field Replaceable Unit (FRU) area. The default is 1086 1024. 1087 1088 ``frudatafile=file`` 1089 file containing raw Field Replaceable Unit (FRU) inventory data. 1090 The default is none. 1091 1092 ``guid=uuid`` 1093 value for the GUID for the BMC, in standard UUID format. If this 1094 is set, get "Get GUID" command to the BMC will return it. 1095 Otherwise "Get GUID" will return an error. 1096 1097``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1098 Add a connection to an external IPMI BMC simulator. Instead of 1099 locally emulating the BMC like the above item, instead connect to an 1100 external entity that provides the IPMI services. 1101 1102 A connection is made to an external BMC simulator. If you do this, 1103 it is strongly recommended that you use the "reconnect=" chardev 1104 option to reconnect to the simulator if the connection is lost. Note 1105 that if this is not used carefully, it can be a security issue, as 1106 the interface has the ability to send resets, NMIs, and power off 1107 the VM. It's best if QEMU makes a connection to an external 1108 simulator running on a secure port on localhost, so neither the 1109 simulator nor QEMU is exposed to any outside network. 1110 1111 See the "lanserv/README.vm" file in the OpenIPMI library for more 1112 details on the external interface. 1113 1114``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1115 Add a KCS IPMI interface on the ISA bus. This also adds a 1116 corresponding ACPI and SMBIOS entries, if appropriate. 1117 1118 ``bmc=id`` 1119 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1120 above. 1121 1122 ``ioport=val`` 1123 Define the I/O address of the interface. The default is 0xca0 1124 for KCS. 1125 1126 ``irq=val`` 1127 Define the interrupt to use. The default is 5. To disable 1128 interrupts, set this to 0. 1129 1130``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1131 Like the KCS interface, but defines a BT interface. The default port 1132 is 0xe4 and the default interrupt is 5. 1133 1134``-device pci-ipmi-kcs,bmc=id`` 1135 Add a KCS IPMI interface on the PCI bus. 1136 1137 ``bmc=id`` 1138 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1139 1140``-device pci-ipmi-bt,bmc=id`` 1141 Like the KCS interface, but defines a BT interface on the PCI bus. 1142 1143``-device intel-iommu[,option=...]`` 1144 This is only supported by ``-machine q35``, which will enable Intel VT-d 1145 emulation within the guest. It supports below options: 1146 1147 ``intremap=on|off`` (default: auto) 1148 This enables interrupt remapping feature. It's required to enable 1149 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1150 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1151 The default value is "auto", which will be decided by the mode of 1152 kernel-irqchip. 1153 1154 ``caching-mode=on|off`` (default: off) 1155 This enables caching mode for the VT-d emulated device. When 1156 caching-mode is enabled, each guest DMA buffer mapping will generate an 1157 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1158 a synchronous way. It is required for ``-device vfio-pci`` to work 1159 with the VT-d device, because host assigned devices requires to setup 1160 the DMA mapping on the host before guest DMA starts. 1161 1162 ``device-iotlb=on|off`` (default: off) 1163 This enables device-iotlb capability for the emulated VT-d device. So 1164 far virtio/vhost should be the only real user for this parameter, 1165 paired with ats=on configured for the device. 1166 1167 ``aw-bits=39|48`` (default: 39) 1168 This decides the address width of IOVA address space. The address 1169 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1170 4-level IOMMU page tables. 1171 1172 Please also refer to the wiki page for general scenarios of VT-d 1173 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1174 1175``-device virtio-iommu-pci[,option=...]`` 1176 This is only supported by ``-machine q35`` (x86_64) and ``-machine virt`` (ARM). 1177 It supports below options: 1178 1179 ``granule=val`` (possible values are 4k, 8k, 16k, 64k and host; default: host) 1180 This decides the default granule to be be exposed by the 1181 virtio-iommu. If host, the granule matches the host page size. 1182 1183 ``aw-bits=val`` (val between 32 and 64, default depends on machine) 1184 This decides the address width of the IOVA address space. 1185 1186ERST 1187 1188DEF("name", HAS_ARG, QEMU_OPTION_name, 1189 "-name string1[,process=string2][,debug-threads=on|off]\n" 1190 " set the name of the guest\n" 1191 " string1 sets the window title and string2 the process name\n" 1192 " When debug-threads is enabled, individual threads are given a separate name\n" 1193 " NOTE: The thread names are for debugging and not a stable API.\n", 1194 QEMU_ARCH_ALL) 1195SRST 1196``-name name`` 1197 Sets the name of the guest. This name will be displayed in the SDL 1198 window caption. The name will also be used for the VNC server. Also 1199 optionally set the top visible process name in Linux. Naming of 1200 individual threads can also be enabled on Linux to aid debugging. 1201ERST 1202 1203DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1204 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1205 " specify machine UUID\n", QEMU_ARCH_ALL) 1206SRST 1207``-uuid uuid`` 1208 Set system UUID. 1209ERST 1210 1211DEFHEADING() 1212 1213DEFHEADING(Block device options:) 1214 1215SRST 1216The QEMU block device handling options have a long history and 1217have gone through several iterations as the feature set and complexity 1218of the block layer have grown. Many online guides to QEMU often 1219reference older and deprecated options, which can lead to confusion. 1220 1221The most explicit way to describe disks is to use a combination of 1222``-device`` to specify the hardware device and ``-blockdev`` to 1223describe the backend. The device defines what the guest sees and the 1224backend describes how QEMU handles the data. It is the only guaranteed 1225stable interface for describing block devices and as such is 1226recommended for management tools and scripting. 1227 1228The ``-drive`` option combines the device and backend into a single 1229command line option which is a more human friendly. There is however no 1230interface stability guarantee although some older board models still 1231need updating to work with the modern blockdev forms. 1232 1233Older options like ``-hda`` are essentially macros which expand into 1234``-drive`` options for various drive interfaces. The original forms 1235bake in a lot of assumptions from the days when QEMU was emulating a 1236legacy PC, they are not recommended for modern configurations. 1237 1238ERST 1239 1240DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1241 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1242DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1243SRST 1244``-fda file`` 1245 \ 1246``-fdb file`` 1247 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1248 the System Emulation Users Guide). 1249ERST 1250 1251DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1252 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1253DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1254DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1255 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1256DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1257SRST 1258``-hda file`` 1259 \ 1260``-hdb file`` 1261 \ 1262``-hdc file`` 1263 \ 1264``-hdd file`` 1265 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1266 emulated machine (this is for example the IDE bus on most x86 machines, 1267 but it can also be SCSI, virtio or something else on other target 1268 architectures). See also the :ref:`disk images` chapter in the System 1269 Emulation Users Guide. 1270ERST 1271 1272DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1273 "-cdrom file use 'file' as CD-ROM image\n", 1274 QEMU_ARCH_ALL) 1275SRST 1276``-cdrom file`` 1277 Use file as CD-ROM image on the default bus of the emulated machine 1278 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1279 at the same time there). On systems that support it, you can use the 1280 host CD-ROM by using ``/dev/cdrom`` as filename. 1281ERST 1282 1283DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1284 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1285 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1286 " [,read-only=on|off][,auto-read-only=on|off]\n" 1287 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1288 " [,driver specific parameters...]\n" 1289 " configure a block backend\n", QEMU_ARCH_ALL) 1290SRST 1291``-blockdev option[,option[,option[,...]]]`` 1292 Define a new block driver node. Some of the options apply to all 1293 block drivers, other options are only accepted for a specific block 1294 driver. See below for a list of generic options and options for the 1295 most common block drivers. 1296 1297 Options that expect a reference to another node (e.g. ``file``) can 1298 be given in two ways. Either you specify the node name of an already 1299 existing node (file=node-name), or you define a new node inline, 1300 adding options for the referenced node after a dot 1301 (file.filename=path,file.aio=native). 1302 1303 A block driver node created with ``-blockdev`` can be used for a 1304 guest device by specifying its node name for the ``drive`` property 1305 in a ``-device`` argument that defines a block device. 1306 1307 ``Valid options for any block driver node:`` 1308 ``driver`` 1309 Specifies the block driver to use for the given node. 1310 1311 ``node-name`` 1312 This defines the name of the block driver node by which it 1313 will be referenced later. The name must be unique, i.e. it 1314 must not match the name of a different block driver node, or 1315 (if you use ``-drive`` as well) the ID of a drive. 1316 1317 If no node name is specified, it is automatically generated. 1318 The generated node name is not intended to be predictable 1319 and changes between QEMU invocations. For the top level, an 1320 explicit node name must be specified. 1321 1322 ``read-only`` 1323 Open the node read-only. Guest write attempts will fail. 1324 1325 Note that some block drivers support only read-only access, 1326 either generally or in certain configurations. In this case, 1327 the default value ``read-only=off`` does not work and the 1328 option must be specified explicitly. 1329 1330 ``auto-read-only`` 1331 If ``auto-read-only=on`` is set, QEMU may fall back to 1332 read-only usage even when ``read-only=off`` is requested, or 1333 even switch between modes as needed, e.g. depending on 1334 whether the image file is writable or whether a writing user 1335 is attached to the node. 1336 1337 ``force-share`` 1338 Override the image locking system of QEMU by forcing the 1339 node to utilize weaker shared access for permissions where 1340 it would normally request exclusive access. When there is 1341 the potential for multiple instances to have the same file 1342 open (whether this invocation of QEMU is the first or the 1343 second instance), both instances must permit shared access 1344 for the second instance to succeed at opening the file. 1345 1346 Enabling ``force-share=on`` requires ``read-only=on``. 1347 1348 ``cache.direct`` 1349 The host page cache can be avoided with ``cache.direct=on``. 1350 This will attempt to do disk IO directly to the guest's 1351 memory. QEMU may still perform an internal copy of the data. 1352 1353 ``cache.no-flush`` 1354 In case you don't care about data integrity over host 1355 failures, you can use ``cache.no-flush=on``. This option 1356 tells QEMU that it never needs to write any data to the disk 1357 but can instead keep things in cache. If anything goes 1358 wrong, like your host losing power, the disk storage getting 1359 disconnected accidentally, etc. your image will most 1360 probably be rendered unusable. 1361 1362 ``discard=discard`` 1363 discard is one of "ignore" (or "off") or "unmap" (or "on") 1364 and controls whether ``discard`` (also known as ``trim`` or 1365 ``unmap``) requests are ignored or passed to the filesystem. 1366 Some machine types may not support discard requests. 1367 1368 ``detect-zeroes=detect-zeroes`` 1369 detect-zeroes is "off", "on" or "unmap" and enables the 1370 automatic conversion of plain zero writes by the OS to 1371 driver specific optimized zero write commands. You may even 1372 choose "unmap" if discard is set to "unmap" to allow a zero 1373 write to be converted to an ``unmap`` operation. 1374 1375 ``Driver-specific options for file`` 1376 This is the protocol-level block driver for accessing regular 1377 files. 1378 1379 ``filename`` 1380 The path to the image file in the local filesystem 1381 1382 ``aio`` 1383 Specifies the AIO backend (threads/native/io_uring, 1384 default: threads) 1385 1386 ``locking`` 1387 Specifies whether the image file is protected with Linux OFD 1388 / POSIX locks. The default is to use the Linux Open File 1389 Descriptor API if available, otherwise no lock is applied. 1390 (auto/on/off, default: auto) 1391 1392 Example: 1393 1394 :: 1395 1396 -blockdev driver=file,node-name=disk,filename=disk.img 1397 1398 ``Driver-specific options for raw`` 1399 This is the image format block driver for raw images. It is 1400 usually stacked on top of a protocol level block driver such as 1401 ``file``. 1402 1403 ``file`` 1404 Reference to or definition of the data source block driver 1405 node (e.g. a ``file`` driver node) 1406 1407 Example 1: 1408 1409 :: 1410 1411 -blockdev driver=file,node-name=disk_file,filename=disk.img 1412 -blockdev driver=raw,node-name=disk,file=disk_file 1413 1414 Example 2: 1415 1416 :: 1417 1418 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1419 1420 ``Driver-specific options for qcow2`` 1421 This is the image format block driver for qcow2 images. It is 1422 usually stacked on top of a protocol level block driver such as 1423 ``file``. 1424 1425 ``file`` 1426 Reference to or definition of the data source block driver 1427 node (e.g. a ``file`` driver node) 1428 1429 ``backing`` 1430 Reference to or definition of the backing file block device 1431 (default is taken from the image file). It is allowed to 1432 pass ``null`` here in order to disable the default backing 1433 file. 1434 1435 ``lazy-refcounts`` 1436 Whether to enable the lazy refcounts feature (on/off; 1437 default is taken from the image file) 1438 1439 ``cache-size`` 1440 The maximum total size of the L2 table and refcount block 1441 caches in bytes (default: the sum of l2-cache-size and 1442 refcount-cache-size) 1443 1444 ``l2-cache-size`` 1445 The maximum size of the L2 table cache in bytes (default: if 1446 cache-size is not specified - 32M on Linux platforms, and 8M 1447 on non-Linux platforms; otherwise, as large as possible 1448 within the cache-size, while permitting the requested or the 1449 minimal refcount cache size) 1450 1451 ``refcount-cache-size`` 1452 The maximum size of the refcount block cache in bytes 1453 (default: 4 times the cluster size; or if cache-size is 1454 specified, the part of it which is not used for the L2 1455 cache) 1456 1457 ``cache-clean-interval`` 1458 Clean unused entries in the L2 and refcount caches. The 1459 interval is in seconds. The default value is 600 on 1460 supporting platforms, and 0 on other platforms. Setting it 1461 to 0 disables this feature. 1462 1463 ``pass-discard-request`` 1464 Whether discard requests to the qcow2 device should be 1465 forwarded to the data source (on/off; default: on if 1466 discard=unmap is specified, off otherwise) 1467 1468 ``pass-discard-snapshot`` 1469 Whether discard requests for the data source should be 1470 issued when a snapshot operation (e.g. deleting a snapshot) 1471 frees clusters in the qcow2 file (on/off; default: on) 1472 1473 ``pass-discard-other`` 1474 Whether discard requests for the data source should be 1475 issued on other occasions where a cluster gets freed 1476 (on/off; default: off) 1477 1478 ``discard-no-unref`` 1479 When enabled, data clusters will remain preallocated when they are 1480 no longer used, e.g. because they are discarded or converted to 1481 zero clusters. As usual, whether the old data is discarded or kept 1482 on the protocol level (i.e. in the image file) depends on the 1483 setting of the pass-discard-request option. Keeping the clusters 1484 preallocated prevents qcow2 fragmentation that would otherwise be 1485 caused by freeing and re-allocating them later. Besides potential 1486 performance degradation, such fragmentation can lead to increased 1487 allocation of clusters past the end of the image file, 1488 resulting in image files whose file length can grow much larger 1489 than their guest disk size would suggest. 1490 If image file length is of concern (e.g. when storing qcow2 1491 images directly on block devices), you should consider enabling 1492 this option. 1493 1494 ``overlap-check`` 1495 Which overlap checks to perform for writes to the image 1496 (none/constant/cached/all; default: cached). For details or 1497 finer granularity control refer to the QAPI documentation of 1498 ``blockdev-add``. 1499 1500 Example 1: 1501 1502 :: 1503 1504 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1505 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1506 1507 Example 2: 1508 1509 :: 1510 1511 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1512 1513 ``Driver-specific options for other drivers`` 1514 Please refer to the QAPI documentation of the ``blockdev-add`` 1515 QMP command. 1516ERST 1517 1518DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1519 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1520 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1521 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1522 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1523 " [,aio=threads|native|io_uring]\n" 1524 " [,readonly=on|off][,copy-on-read=on|off]\n" 1525 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1526 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1527 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1528 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1529 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1530 " [[,iops_size=is]]\n" 1531 " [[,group=g]]\n" 1532 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1533SRST 1534``-drive option[,option[,option[,...]]]`` 1535 Define a new drive. This includes creating a block driver node (the 1536 backend) as well as a guest device, and is mostly a shortcut for 1537 defining the corresponding ``-blockdev`` and ``-device`` options. 1538 1539 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1540 In addition, it knows the following options: 1541 1542 ``file=file`` 1543 This option defines which disk image (see the :ref:`disk images` 1544 chapter in the System Emulation Users Guide) to use with this drive. 1545 If the filename contains comma, you must double it (for instance, 1546 "file=my,,file" to use file "my,file"). 1547 1548 Special files such as iSCSI devices can be specified using 1549 protocol specific URLs. See the section for "Device URL Syntax" 1550 for more information. 1551 1552 ``if=interface`` 1553 This option defines on which type on interface the drive is 1554 connected. Available types are: ide, scsi, sd, mtd, floppy, 1555 pflash, virtio, none. 1556 1557 ``bus=bus,unit=unit`` 1558 These options define where is connected the drive by defining 1559 the bus number and the unit id. 1560 1561 ``index=index`` 1562 This option defines where the drive is connected by using an 1563 index in the list of available connectors of a given interface 1564 type. 1565 1566 ``media=media`` 1567 This option defines the type of the media: disk or cdrom. 1568 1569 ``snapshot=snapshot`` 1570 snapshot is "on" or "off" and controls snapshot mode for the 1571 given drive (see ``-snapshot``). 1572 1573 ``cache=cache`` 1574 cache is "none", "writeback", "unsafe", "directsync" or 1575 "writethrough" and controls how the host cache is used to access 1576 block data. This is a shortcut that sets the ``cache.direct`` 1577 and ``cache.no-flush`` options (as in ``-blockdev``), and 1578 additionally ``cache.writeback``, which provides a default for 1579 the ``write-cache`` option of block guest devices (as in 1580 ``-device``). The modes correspond to the following settings: 1581 1582 ============= =============== ============ ============== 1583 \ cache.writeback cache.direct cache.no-flush 1584 ============= =============== ============ ============== 1585 writeback on off off 1586 none on on off 1587 writethrough off off off 1588 directsync off on off 1589 unsafe on off on 1590 ============= =============== ============ ============== 1591 1592 The default mode is ``cache=writeback``. 1593 1594 ``aio=aio`` 1595 aio is "threads", "native", or "io_uring" and selects between pthread 1596 based disk I/O, native Linux AIO, or Linux io_uring API. 1597 1598 ``format=format`` 1599 Specify which disk format will be used rather than detecting the 1600 format. Can be used to specify format=raw to avoid interpreting 1601 an untrusted format header. 1602 1603 ``werror=action,rerror=action`` 1604 Specify which action to take on write and read errors. Valid 1605 actions are: "ignore" (ignore the error and try to continue), 1606 "stop" (pause QEMU), "report" (report the error to the guest), 1607 "enospc" (pause QEMU only if the host disk is full; report the 1608 error to the guest otherwise). The default setting is 1609 ``werror=enospc`` and ``rerror=report``. 1610 1611 ``copy-on-read=copy-on-read`` 1612 copy-on-read is "on" or "off" and enables whether to copy read 1613 backing file sectors into the image file. 1614 1615 ``bps=b,bps_rd=r,bps_wr=w`` 1616 Specify bandwidth throttling limits in bytes per second, either 1617 for all request types or for reads or writes only. Small values 1618 can lead to timeouts or hangs inside the guest. A safe minimum 1619 for disks is 2 MB/s. 1620 1621 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1622 Specify bursts in bytes per second, either for all request types 1623 or for reads or writes only. Bursts allow the guest I/O to spike 1624 above the limit temporarily. 1625 1626 ``iops=i,iops_rd=r,iops_wr=w`` 1627 Specify request rate limits in requests per second, either for 1628 all request types or for reads or writes only. 1629 1630 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1631 Specify bursts in requests per second, either for all request 1632 types or for reads or writes only. Bursts allow the guest I/O to 1633 spike above the limit temporarily. 1634 1635 ``iops_size=is`` 1636 Let every is bytes of a request count as a new request for iops 1637 throttling purposes. Use this option to prevent guests from 1638 circumventing iops limits by sending fewer but larger requests. 1639 1640 ``group=g`` 1641 Join a throttling quota group with given name g. All drives that 1642 are members of the same group are accounted for together. Use 1643 this option to prevent guests from circumventing throttling 1644 limits by using many small disks instead of a single larger 1645 disk. 1646 1647 By default, the ``cache.writeback=on`` mode is used. It will report 1648 data writes as completed as soon as the data is present in the host 1649 page cache. This is safe as long as your guest OS makes sure to 1650 correctly flush disk caches where needed. If your guest OS does not 1651 handle volatile disk write caches correctly and your host crashes or 1652 loses power, then the guest may experience data corruption. 1653 1654 For such guests, you should consider using ``cache.writeback=off``. 1655 This means that the host page cache will be used to read and write 1656 data, but write notification will be sent to the guest only after 1657 QEMU has made sure to flush each write to the disk. Be aware that 1658 this has a major impact on performance. 1659 1660 When using the ``-snapshot`` option, unsafe caching is always used. 1661 1662 Copy-on-read avoids accessing the same backing file sectors 1663 repeatedly and is useful when the backing file is over a slow 1664 network. By default copy-on-read is off. 1665 1666 Instead of ``-cdrom`` you can use: 1667 1668 .. parsed-literal:: 1669 1670 |qemu_system| -drive file=file,index=2,media=cdrom 1671 1672 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1673 1674 .. parsed-literal:: 1675 1676 |qemu_system| -drive file=file,index=0,media=disk 1677 |qemu_system| -drive file=file,index=1,media=disk 1678 |qemu_system| -drive file=file,index=2,media=disk 1679 |qemu_system| -drive file=file,index=3,media=disk 1680 1681 You can open an image using pre-opened file descriptors from an fd 1682 set: 1683 1684 .. parsed-literal:: 1685 1686 |qemu_system| \\ 1687 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1688 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1689 -drive file=/dev/fdset/2,index=0,media=disk 1690 1691 You can connect a CDROM to the slave of ide0: 1692 1693 .. parsed-literal:: 1694 1695 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1696 1697 If you don't specify the "file=" argument, you define an empty 1698 drive: 1699 1700 .. parsed-literal:: 1701 1702 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1703 1704 Instead of ``-fda``, ``-fdb``, you can use: 1705 1706 .. parsed-literal:: 1707 1708 |qemu_system_x86| -drive file=file,index=0,if=floppy 1709 |qemu_system_x86| -drive file=file,index=1,if=floppy 1710 1711 By default, interface is "ide" and index is automatically 1712 incremented: 1713 1714 .. parsed-literal:: 1715 1716 |qemu_system_x86| -drive file=a -drive file=b 1717 1718 is interpreted like: 1719 1720 .. parsed-literal:: 1721 1722 |qemu_system_x86| -hda a -hdb b 1723ERST 1724 1725DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1726 "-mtdblock file use 'file' as on-board Flash memory image\n", 1727 QEMU_ARCH_ALL) 1728SRST 1729``-mtdblock file`` 1730 Use file as on-board Flash memory image. 1731ERST 1732 1733DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1734 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1735SRST 1736``-sd file`` 1737 Use file as SecureDigital card image. 1738ERST 1739 1740DEF("snapshot", 0, QEMU_OPTION_snapshot, 1741 "-snapshot write to temporary files instead of disk image files\n", 1742 QEMU_ARCH_ALL) 1743SRST 1744``-snapshot`` 1745 Write to temporary files instead of disk image files. In this case, 1746 the raw disk image you use is not written back. You can however 1747 force the write back by pressing C-a s (see the :ref:`disk images` 1748 chapter in the System Emulation Users Guide). 1749 1750 .. warning:: 1751 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1752 to manually create snapshot images to attach to your blockdev). 1753 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1754 can use the 'snapshot' property on your drive declarations 1755 instead of this global option. 1756 1757ERST 1758 1759DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1760 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1761 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1762 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1763 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1764 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1765 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1766 " [[,throttling.iops-size=is]]\n" 1767 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1768 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1769 "-fsdev synth,id=id\n", 1770 QEMU_ARCH_ALL) 1771 1772SRST 1773``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1774 \ 1775``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1776 \ 1777``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1778 \ 1779``-fsdev synth,id=id[,readonly=on]`` 1780 Define a new file system device. Valid options are: 1781 1782 ``local`` 1783 Accesses to the filesystem are done by QEMU. 1784 1785 ``proxy`` 1786 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1787 option is deprecated (since QEMU 8.1) and will be removed in a future 1788 version of QEMU. Use ``local`` instead. 1789 1790 ``synth`` 1791 Synthetic filesystem, only used by QTests. 1792 1793 ``id=id`` 1794 Specifies identifier for this device. 1795 1796 ``path=path`` 1797 Specifies the export path for the file system device. Files 1798 under this path will be available to the 9p client on the guest. 1799 1800 ``security_model=security_model`` 1801 Specifies the security model to be used for this export path. 1802 Supported security models are "passthrough", "mapped-xattr", 1803 "mapped-file" and "none". In "passthrough" security model, files 1804 are stored using the same credentials as they are created on the 1805 guest. This requires QEMU to run as root. In "mapped-xattr" 1806 security model, some of the file attributes like uid, gid, mode 1807 bits and link target are stored as file attributes. For 1808 "mapped-file" these attributes are stored in the hidden 1809 .virtfs\_metadata directory. Directories exported by this 1810 security model cannot interact with other unix tools. "none" 1811 security model is same as passthrough except the sever won't 1812 report failures if it fails to set file attributes like 1813 ownership. Security model is mandatory only for local fsdriver. 1814 Other fsdrivers (like proxy) don't take security model as a 1815 parameter. 1816 1817 ``writeout=writeout`` 1818 This is an optional argument. The only supported value is 1819 "immediate". This means that host page cache will be used to 1820 read and write data but write notification will be sent to the 1821 guest only when the data has been reported as written by the 1822 storage subsystem. 1823 1824 ``readonly=on`` 1825 Enables exporting 9p share as a readonly mount for guests. By 1826 default read-write access is given. 1827 1828 ``socket=socket`` 1829 Enables proxy filesystem driver to use passed socket file for 1830 communicating with virtfs-proxy-helper(1). 1831 1832 ``sock_fd=sock_fd`` 1833 Enables proxy filesystem driver to use passed socket descriptor 1834 for communicating with virtfs-proxy-helper(1). Usually a helper 1835 like libvirt will create socketpair and pass one of the fds as 1836 sock\_fd. 1837 1838 ``fmode=fmode`` 1839 Specifies the default mode for newly created files on the host. 1840 Works only with security models "mapped-xattr" and 1841 "mapped-file". 1842 1843 ``dmode=dmode`` 1844 Specifies the default mode for newly created directories on the 1845 host. Works only with security models "mapped-xattr" and 1846 "mapped-file". 1847 1848 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1849 Specify bandwidth throttling limits in bytes per second, either 1850 for all request types or for reads or writes only. 1851 1852 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1853 Specify bursts in bytes per second, either for all request types 1854 or for reads or writes only. Bursts allow the guest I/O to spike 1855 above the limit temporarily. 1856 1857 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1858 Specify request rate limits in requests per second, either for 1859 all request types or for reads or writes only. 1860 1861 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1862 Specify bursts in requests per second, either for all request 1863 types or for reads or writes only. Bursts allow the guest I/O to 1864 spike above the limit temporarily. 1865 1866 ``throttling.iops-size=is`` 1867 Let every is bytes of a request count as a new request for iops 1868 throttling purposes. 1869 1870 -fsdev option is used along with -device driver "virtio-9p-...". 1871 1872``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1873 Options for virtio-9p-... driver are: 1874 1875 ``type`` 1876 Specifies the variant to be used. Supported values are "pci", 1877 "ccw" or "device", depending on the machine type. 1878 1879 ``fsdev=id`` 1880 Specifies the id value specified along with -fsdev option. 1881 1882 ``mount_tag=mount_tag`` 1883 Specifies the tag name to be used by the guest to mount this 1884 export point. 1885ERST 1886 1887DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1888 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1889 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1890 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1891 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1892 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1893 QEMU_ARCH_ALL) 1894 1895SRST 1896``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1897 \ 1898``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1899 \ 1900``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1901 \ 1902``-virtfs synth,mount_tag=mount_tag`` 1903 Define a new virtual filesystem device and expose it to the guest using 1904 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1905 directory on host is made directly accessible by guest as a pass-through 1906 file system by using the 9P network protocol for communication between 1907 host and guests, if desired even accessible, shared by several guests 1908 simultaneously. 1909 1910 Note that ``-virtfs`` is actually just a convenience shortcut for its 1911 generalized form ``-fsdev -device virtio-9p-pci``. 1912 1913 The general form of pass-through file system options are: 1914 1915 ``local`` 1916 Accesses to the filesystem are done by QEMU. 1917 1918 ``proxy`` 1919 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1920 This option is deprecated (since QEMU 8.1) and will be removed in a 1921 future version of QEMU. Use ``local`` instead. 1922 1923 ``synth`` 1924 Synthetic filesystem, only used by QTests. 1925 1926 ``id=id`` 1927 Specifies identifier for the filesystem device 1928 1929 ``path=path`` 1930 Specifies the export path for the file system device. Files 1931 under this path will be available to the 9p client on the guest. 1932 1933 ``security_model=security_model`` 1934 Specifies the security model to be used for this export path. 1935 Supported security models are "passthrough", "mapped-xattr", 1936 "mapped-file" and "none". In "passthrough" security model, files 1937 are stored using the same credentials as they are created on the 1938 guest. This requires QEMU to run as root. In "mapped-xattr" 1939 security model, some of the file attributes like uid, gid, mode 1940 bits and link target are stored as file attributes. For 1941 "mapped-file" these attributes are stored in the hidden 1942 .virtfs\_metadata directory. Directories exported by this 1943 security model cannot interact with other unix tools. "none" 1944 security model is same as passthrough except the sever won't 1945 report failures if it fails to set file attributes like 1946 ownership. Security model is mandatory only for local fsdriver. 1947 Other fsdrivers (like proxy) don't take security model as a 1948 parameter. 1949 1950 ``writeout=writeout`` 1951 This is an optional argument. The only supported value is 1952 "immediate". This means that host page cache will be used to 1953 read and write data but write notification will be sent to the 1954 guest only when the data has been reported as written by the 1955 storage subsystem. 1956 1957 ``readonly=on`` 1958 Enables exporting 9p share as a readonly mount for guests. By 1959 default read-write access is given. 1960 1961 ``socket=socket`` 1962 Enables proxy filesystem driver to use passed socket file for 1963 communicating with virtfs-proxy-helper(1). Usually a helper like 1964 libvirt will create socketpair and pass one of the fds as 1965 sock\_fd. 1966 1967 ``sock_fd`` 1968 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1969 socket descriptor for interfacing with virtfs-proxy-helper(1). 1970 1971 ``fmode=fmode`` 1972 Specifies the default mode for newly created files on the host. 1973 Works only with security models "mapped-xattr" and 1974 "mapped-file". 1975 1976 ``dmode=dmode`` 1977 Specifies the default mode for newly created directories on the 1978 host. Works only with security models "mapped-xattr" and 1979 "mapped-file". 1980 1981 ``mount_tag=mount_tag`` 1982 Specifies the tag name to be used by the guest to mount this 1983 export point. 1984 1985 ``multidevs=multidevs`` 1986 Specifies how to deal with multiple devices being shared with a 1987 9p export. Supported behaviours are either "remap", "forbid" or 1988 "warn". The latter is the default behaviour on which virtfs 9p 1989 expects only one device to be shared with the same export, and 1990 if more than one device is shared and accessed via the same 9p 1991 export then only a warning message is logged (once) by qemu on 1992 host side. In order to avoid file ID collisions on guest you 1993 should either create a separate virtfs export for each device to 1994 be shared with guests (recommended way) or you might use "remap" 1995 instead which allows you to share multiple devices with only one 1996 export instead, which is achieved by remapping the original 1997 inode numbers from host to guest in a way that would prevent 1998 such collisions. Remapping inodes in such use cases is required 1999 because the original device IDs from host are never passed and 2000 exposed on guest. Instead all files of an export shared with 2001 virtfs always share the same device id on guest. So two files 2002 with identical inode numbers but from actually different devices 2003 on host would otherwise cause a file ID collision and hence 2004 potential misbehaviours on guest. "forbid" on the other hand 2005 assumes like "warn" that only one device is shared by the same 2006 export, however it will not only log a warning message but also 2007 deny access to additional devices on guest. Note though that 2008 "forbid" does currently not block all possible file access 2009 operations (e.g. readdir() would still return entries from other 2010 devices). 2011ERST 2012 2013DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 2014 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 2015 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 2016 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 2017 " [,timeout=timeout]\n" 2018 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2019 2020SRST 2021``-iscsi`` 2022 Configure iSCSI session parameters. 2023ERST 2024 2025DEFHEADING() 2026 2027DEFHEADING(USB convenience options:) 2028 2029DEF("usb", 0, QEMU_OPTION_usb, 2030 "-usb enable on-board USB host controller (if not enabled by default)\n", 2031 QEMU_ARCH_ALL) 2032SRST 2033``-usb`` 2034 Enable USB emulation on machine types with an on-board USB host 2035 controller (if not enabled by default). Note that on-board USB host 2036 controllers may not support USB 3.0. In this case 2037 ``-device qemu-xhci`` can be used instead on machines with PCI. 2038ERST 2039 2040DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2041 "-usbdevice name add the host or guest USB device 'name'\n", 2042 QEMU_ARCH_ALL) 2043SRST 2044``-usbdevice devname`` 2045 Add the USB device devname, and enable an on-board USB controller 2046 if possible and necessary (just like it can be done via 2047 ``-machine usb=on``). Note that this option is mainly intended for 2048 the user's convenience only. More fine-grained control can be 2049 achieved by selecting a USB host controller (if necessary) and the 2050 desired USB device via the ``-device`` option instead. For example, 2051 instead of using ``-usbdevice mouse`` it is possible to use 2052 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2053 to a USB 3.0 controller instead (at least on machines that support 2054 PCI and do not have an USB controller enabled by default yet). 2055 For more details, see the chapter about 2056 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2057 Possible devices for devname are: 2058 2059 ``braille`` 2060 Braille device. This will use BrlAPI to display the braille 2061 output on a real or fake device (i.e. it also creates a 2062 corresponding ``braille`` chardev automatically beside the 2063 ``usb-braille`` USB device). 2064 2065 ``keyboard`` 2066 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2067 2068 ``mouse`` 2069 Virtual Mouse. This will override the PS/2 mouse emulation when 2070 activated. 2071 2072 ``tablet`` 2073 Pointer device that uses absolute coordinates (like a 2074 touchscreen). This means QEMU is able to report the mouse 2075 position without having to grab the mouse. Also overrides the 2076 PS/2 mouse emulation when activated. 2077 2078 ``wacom-tablet`` 2079 Wacom PenPartner USB tablet. 2080 2081 2082ERST 2083 2084DEFHEADING() 2085 2086DEFHEADING(Display options:) 2087 2088DEF("display", HAS_ARG, QEMU_OPTION_display, 2089#if defined(CONFIG_SPICE) 2090 "-display spice-app[,gl=on|off]\n" 2091#endif 2092#if defined(CONFIG_SDL) 2093 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2094 " [,window-close=on|off]\n" 2095#endif 2096#if defined(CONFIG_GTK) 2097 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2098 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2099 " [,show-menubar=on|off][,zoom-to-fit=on|off]\n" 2100#endif 2101#if defined(CONFIG_VNC) 2102 "-display vnc=<display>[,<optargs>]\n" 2103#endif 2104#if defined(CONFIG_CURSES) 2105 "-display curses[,charset=<encoding>]\n" 2106#endif 2107#if defined(CONFIG_COCOA) 2108 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2109 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2110 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2111#endif 2112#if defined(CONFIG_OPENGL) 2113 "-display egl-headless[,rendernode=<file>]\n" 2114#endif 2115#if defined(CONFIG_DBUS_DISPLAY) 2116 "-display dbus[,addr=<dbusaddr>]\n" 2117 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2118#endif 2119 "-display none\n" 2120 " select display backend type\n" 2121 " The default display is equivalent to\n " 2122#if defined(CONFIG_GTK) 2123 "\"-display gtk\"\n" 2124#elif defined(CONFIG_SDL) 2125 "\"-display sdl\"\n" 2126#elif defined(CONFIG_COCOA) 2127 "\"-display cocoa\"\n" 2128#elif defined(CONFIG_VNC) 2129 "\"-vnc localhost:0,to=99,id=default\"\n" 2130#else 2131 "\"-display none\"\n" 2132#endif 2133 , QEMU_ARCH_ALL) 2134SRST 2135``-display type`` 2136 Select type of display to use. Use ``-display help`` to list the available 2137 display types. Valid values for type are 2138 2139 ``spice-app[,gl=on|off]`` 2140 Start QEMU as a Spice server and launch the default Spice client 2141 application. The Spice server will redirect the serial consoles 2142 and QEMU monitors. (Since 4.0) 2143 2144 ``dbus`` 2145 Export the display over D-Bus interfaces. (Since 7.0) 2146 2147 The connection is registered with the "org.qemu" name (and queued when 2148 already owned). 2149 2150 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2151 2152 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2153 2154 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2155 will share framebuffers with DMABUF file descriptors). 2156 2157 ``sdl`` 2158 Display video output via SDL (usually in a separate graphics 2159 window; see the SDL documentation for other possibilities). 2160 Valid parameters are: 2161 2162 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2163 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2164 either ``lshift-lctrl-lalt`` or ``rctrl``. 2165 2166 ``gl=on|off|core|es`` : Use OpenGL for displaying 2167 2168 ``show-cursor=on|off`` : Force showing the mouse cursor 2169 2170 ``window-close=on|off`` : Allow to quit qemu with window close button 2171 2172 ``gtk`` 2173 Display video output in a GTK window. This interface provides 2174 drop-down menus and other UI elements to configure and control 2175 the VM during runtime. Valid parameters are: 2176 2177 ``full-screen=on|off`` : Start in fullscreen mode 2178 2179 ``gl=on|off`` : Use OpenGL for displaying 2180 2181 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2182 2183 ``show-tabs=on|off`` : Display the tab bar for switching between the 2184 various graphical interfaces (e.g. VGA and 2185 virtual console character devices) by default. 2186 2187 ``show-cursor=on|off`` : Force showing the mouse cursor 2188 2189 ``window-close=on|off`` : Allow to quit qemu with window close button 2190 2191 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2192 2193 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2194 defaults to "off" 2195 2196 ``curses[,charset=<encoding>]`` 2197 Display video output via curses. For graphics device models 2198 which support a text mode, QEMU can display this output using a 2199 curses/ncurses interface. Nothing is displayed when the graphics 2200 device is in graphical mode or if the graphics device does not 2201 support a text mode. Generally only the VGA device models 2202 support text mode. The font charset used by the guest can be 2203 specified with the ``charset`` option, for example 2204 ``charset=CP850`` for IBM CP850 encoding. The default is 2205 ``CP437``. 2206 2207 ``cocoa`` 2208 Display video output in a Cocoa window. Mac only. This interface 2209 provides drop-down menus and other UI elements to configure and 2210 control the VM during runtime. Valid parameters are: 2211 2212 ``full-grab=on|off`` : Capture all key presses, including system combos. 2213 This requires accessibility permissions, since it 2214 performs a global grab on key events. 2215 (default: off) See 2216 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2217 2218 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2219 key codes match their position on non-Mac 2220 keyboards and you can use Meta/Super and Alt 2221 where you expect them. (default: off) 2222 2223 ``show-cursor=on|off`` : Force showing the mouse cursor 2224 2225 ``left-command-key=on|off`` : Disable forwarding left command key to host 2226 2227 ``full-screen=on|off`` : Start in fullscreen mode 2228 2229 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2230 defaults to "off" 2231 2232 ``egl-headless[,rendernode=<file>]`` 2233 Offload all OpenGL operations to a local DRI device. For any 2234 graphical display, this display needs to be paired with either 2235 VNC or SPICE displays. 2236 2237 ``vnc=<display>`` 2238 Start a VNC server on display <display> 2239 2240 ``none`` 2241 Do not display video output. The guest will still see an 2242 emulated graphics card, but its output will not be displayed to 2243 the QEMU user. This option differs from the -nographic option in 2244 that it only affects what is done with video output; -nographic 2245 also changes the destination of the serial and parallel port 2246 data. 2247ERST 2248 2249DEF("nographic", 0, QEMU_OPTION_nographic, 2250 "-nographic disable graphical output and redirect serial I/Os to console\n", 2251 QEMU_ARCH_ALL) 2252SRST 2253``-nographic`` 2254 Normally, if QEMU is compiled with graphical window support, it 2255 displays output such as guest graphics, guest console, and the QEMU 2256 monitor in a window. With this option, you can totally disable 2257 graphical output so that QEMU is a simple command line application. 2258 The emulated serial port is redirected on the console and muxed with 2259 the monitor (unless redirected elsewhere explicitly). Therefore, you 2260 can still use QEMU to debug a Linux kernel with a serial console. 2261 Use C-a h for help on switching between the console and monitor. 2262ERST 2263 2264#ifdef CONFIG_SPICE 2265DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2266 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2267 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2268 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2269 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2270 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2271 " [,tls-ciphers=<list>]\n" 2272 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2273 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2274 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2275 " [,password-secret=<secret-id>]\n" 2276 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2277 " [,jpeg-wan-compression=[auto|never|always]]\n" 2278 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2279 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2280 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2281 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2282 " [,gl=[on|off]][,rendernode=<file>]\n" 2283 " enable spice\n" 2284 " at least one of {port, tls-port} is mandatory\n", 2285 QEMU_ARCH_ALL) 2286#endif 2287SRST 2288``-spice option[,option[,...]]`` 2289 Enable the spice remote desktop protocol. Valid options are 2290 2291 ``port=<nr>`` 2292 Set the TCP port spice is listening on for plaintext channels. 2293 2294 ``addr=<addr>`` 2295 Set the IP address spice is listening on. Default is any 2296 address. 2297 2298 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2299 Force using the specified IP version. 2300 2301 ``password-secret=<secret-id>`` 2302 Set the ID of the ``secret`` object containing the password 2303 you need to authenticate. 2304 2305 ``sasl=on|off`` 2306 Require that the client use SASL to authenticate with the spice. 2307 The exact choice of authentication method used is controlled 2308 from the system / user's SASL configuration file for the 'qemu' 2309 service. This is typically found in /etc/sasl2/qemu.conf. If 2310 running QEMU as an unprivileged user, an environment variable 2311 SASL\_CONF\_PATH can be used to make it search alternate 2312 locations for the service config. While some SASL auth methods 2313 can also provide data encryption (eg GSSAPI), it is recommended 2314 that SASL always be combined with the 'tls' and 'x509' settings 2315 to enable use of SSL and server certificates. This ensures a 2316 data encryption preventing compromise of authentication 2317 credentials. 2318 2319 ``disable-ticketing=on|off`` 2320 Allow client connects without authentication. 2321 2322 ``disable-copy-paste=on|off`` 2323 Disable copy paste between the client and the guest. 2324 2325 ``disable-agent-file-xfer=on|off`` 2326 Disable spice-vdagent based file-xfer between the client and the 2327 guest. 2328 2329 ``tls-port=<nr>`` 2330 Set the TCP port spice is listening on for encrypted channels. 2331 2332 ``x509-dir=<dir>`` 2333 Set the x509 file directory. Expects same filenames as -vnc 2334 $display,x509=$dir 2335 2336 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2337 The x509 file names can also be configured individually. 2338 2339 ``tls-ciphers=<list>`` 2340 Specify which ciphers to use. 2341 2342 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2343 Force specific channel to be used with or without TLS 2344 encryption. The options can be specified multiple times to 2345 configure multiple channels. The special name "default" can be 2346 used to set the default mode. For channels which are not 2347 explicitly forced into one mode the spice client is allowed to 2348 pick tls/plaintext as he pleases. 2349 2350 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2351 Configure image compression (lossless). Default is auto\_glz. 2352 2353 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2354 Configure wan image compression (lossy for slow links). Default 2355 is auto. 2356 2357 ``streaming-video=[off|all|filter]`` 2358 Configure video stream detection. Default is off. 2359 2360 ``agent-mouse=[on|off]`` 2361 Enable/disable passing mouse events via vdagent. Default is on. 2362 2363 ``playback-compression=[on|off]`` 2364 Enable/disable audio stream compression (using celt 0.5.1). 2365 Default is on. 2366 2367 ``seamless-migration=[on|off]`` 2368 Enable/disable spice seamless migration. Default is off. 2369 2370 ``gl=[on|off]`` 2371 Enable/disable OpenGL context. Default is off. 2372 2373 ``rendernode=<file>`` 2374 DRM render node for OpenGL rendering. If not specified, it will 2375 pick the first available. (Since 2.9) 2376ERST 2377 2378DEF("portrait", 0, QEMU_OPTION_portrait, 2379 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2380 QEMU_ARCH_ALL) 2381SRST 2382``-portrait`` 2383 Rotate graphical output 90 deg left (only PXA LCD). 2384ERST 2385 2386DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2387 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2388 QEMU_ARCH_ALL) 2389SRST 2390``-rotate deg`` 2391 Rotate graphical output some deg left (only PXA LCD). 2392ERST 2393 2394DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2395 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2396 " select video card type\n", QEMU_ARCH_ALL) 2397SRST 2398``-vga type`` 2399 Select type of VGA card to emulate. Valid values for type are 2400 2401 ``cirrus`` 2402 Cirrus Logic GD5446 Video card. All Windows versions starting 2403 from Windows 95 should recognize and use this graphic card. For 2404 optimal performances, use 16 bit color depth in the guest and 2405 the host OS. (This card was the default before QEMU 2.2) 2406 2407 ``std`` 2408 Standard VGA card with Bochs VBE extensions. If your guest OS 2409 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2410 you want to use high resolution modes (>= 1280x1024x16) then you 2411 should use this option. (This card is the default since QEMU 2412 2.2) 2413 2414 ``vmware`` 2415 VMWare SVGA-II compatible adapter. Use it if you have 2416 sufficiently recent XFree86/XOrg server or Windows guest with a 2417 driver for this card. 2418 2419 ``qxl`` 2420 QXL paravirtual graphic card. It is VGA compatible (including 2421 VESA 2.0 VBE support). Works best with qxl guest drivers 2422 installed though. Recommended choice when using the spice 2423 protocol. 2424 2425 ``tcx`` 2426 (sun4m only) Sun TCX framebuffer. This is the default 2427 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2428 colour depths at a fixed resolution of 1024x768. 2429 2430 ``cg3`` 2431 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2432 framebuffer for sun4m machines available in both 1024x768 2433 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2434 wishing to run older Solaris versions. 2435 2436 ``virtio`` 2437 Virtio VGA card. 2438 2439 ``none`` 2440 Disable VGA card. 2441ERST 2442 2443DEF("full-screen", 0, QEMU_OPTION_full_screen, 2444 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2445SRST 2446``-full-screen`` 2447 Start in full screen. 2448ERST 2449 2450DEF("g", HAS_ARG, QEMU_OPTION_g , 2451 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2452 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2453SRST 2454``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2455 Set the initial graphical resolution and depth (PPC, SPARC only). 2456 2457 For PPC the default is 800x600x32. 2458 2459 For SPARC with the TCX graphics device, the default is 1024x768x8 2460 with the option of 1024x768x24. For cgthree, the default is 2461 1024x768x8 with the option of 1152x900x8 for people who wish to use 2462 OBP. 2463ERST 2464 2465#ifdef CONFIG_VNC 2466DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2467 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2468#endif 2469SRST 2470``-vnc display[,option[,option[,...]]]`` 2471 Normally, if QEMU is compiled with graphical window support, it 2472 displays output such as guest graphics, guest console, and the QEMU 2473 monitor in a window. With this option, you can have QEMU listen on 2474 VNC display display and redirect the VGA display over the VNC 2475 session. It is very useful to enable the usb tablet device when 2476 using this option (option ``-device usb-tablet``). When using the 2477 VNC display, you must use the ``-k`` parameter to set the keyboard 2478 layout if you are not using en-us. Valid syntax for the display is 2479 2480 ``to=L`` 2481 With this option, QEMU will try next available VNC displays, 2482 until the number L, if the originally defined "-vnc display" is 2483 not available, e.g. port 5900+display is already used by another 2484 application. By default, to=0. 2485 2486 ``host:d`` 2487 TCP connections will only be allowed from host on display d. By 2488 convention the TCP port is 5900+d. Optionally, host can be 2489 omitted in which case the server will accept connections from 2490 any host. 2491 2492 ``unix:path`` 2493 Connections will be allowed over UNIX domain sockets where path 2494 is the location of a unix socket to listen for connections on. 2495 2496 ``none`` 2497 VNC is initialized but not started. The monitor ``change`` 2498 command can be used to later start the VNC server. 2499 2500 Following the display value there may be one or more option flags 2501 separated by commas. Valid options are 2502 2503 ``reverse=on|off`` 2504 Connect to a listening VNC client via a "reverse" connection. 2505 The client is specified by the display. For reverse network 2506 connections (host:d,``reverse``), the d argument is a TCP port 2507 number, not a display number. 2508 2509 ``websocket=on|off`` 2510 Opens an additional TCP listening port dedicated to VNC 2511 Websocket connections. If a bare websocket option is given, the 2512 Websocket port is 5700+display. An alternative port can be 2513 specified with the syntax ``websocket``\ =port. 2514 2515 If host is specified connections will only be allowed from this 2516 host. It is possible to control the websocket listen address 2517 independently, using the syntax ``websocket``\ =host:port. 2518 2519 Websocket could be allowed over UNIX domain socket, using the syntax 2520 ``websocket``\ =unix:path, where path is the location of a unix socket 2521 to listen for connections on. 2522 2523 If no TLS credentials are provided, the websocket connection 2524 runs in unencrypted mode. If TLS credentials are provided, the 2525 websocket connection requires encrypted client connections. 2526 2527 ``password=on|off`` 2528 Require that password based authentication is used for client 2529 connections. 2530 2531 The password must be set separately using the ``set_password`` 2532 command in the :ref:`QEMU monitor`. The 2533 syntax to change your password is: 2534 ``set_password <protocol> <password>`` where <protocol> could be 2535 either "vnc" or "spice". 2536 2537 If you would like to change <protocol> password expiration, you 2538 should use ``expire_password <protocol> <expiration-time>`` 2539 where expiration time could be one of the following options: 2540 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2541 make password expire in 60 seconds, or 1335196800 to make 2542 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2543 this date and time). 2544 2545 You can also use keywords "now" or "never" for the expiration 2546 time to allow <protocol> password to expire immediately or never 2547 expire. 2548 2549 ``password-secret=<secret-id>`` 2550 Require that password based authentication is used for client 2551 connections, using the password provided by the ``secret`` 2552 object identified by ``secret-id``. 2553 2554 ``tls-creds=ID`` 2555 Provides the ID of a set of TLS credentials to use to secure the 2556 VNC server. They will apply to both the normal VNC server socket 2557 and the websocket socket (if enabled). Setting TLS credentials 2558 will cause the VNC server socket to enable the VeNCrypt auth 2559 mechanism. The credentials should have been previously created 2560 using the ``-object tls-creds`` argument. 2561 2562 ``tls-authz=ID`` 2563 Provides the ID of the QAuthZ authorization object against which 2564 the client's x509 distinguished name will validated. This object 2565 is only resolved at time of use, so can be deleted and recreated 2566 on the fly while the VNC server is active. If missing, it will 2567 default to denying access. 2568 2569 ``sasl=on|off`` 2570 Require that the client use SASL to authenticate with the VNC 2571 server. The exact choice of authentication method used is 2572 controlled from the system / user's SASL configuration file for 2573 the 'qemu' service. This is typically found in 2574 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2575 an environment variable SASL\_CONF\_PATH can be used to make it 2576 search alternate locations for the service config. While some 2577 SASL auth methods can also provide data encryption (eg GSSAPI), 2578 it is recommended that SASL always be combined with the 'tls' 2579 and 'x509' settings to enable use of SSL and server 2580 certificates. This ensures a data encryption preventing 2581 compromise of authentication credentials. See the 2582 :ref:`VNC security` section in the System Emulation Users Guide 2583 for details on using SASL authentication. 2584 2585 ``sasl-authz=ID`` 2586 Provides the ID of the QAuthZ authorization object against which 2587 the client's SASL username will validated. This object is only 2588 resolved at time of use, so can be deleted and recreated on the 2589 fly while the VNC server is active. If missing, it will default 2590 to denying access. 2591 2592 ``acl=on|off`` 2593 Legacy method for enabling authorization of clients against the 2594 x509 distinguished name and SASL username. It results in the 2595 creation of two ``authz-list`` objects with IDs of 2596 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2597 objects must be configured with the HMP ACL commands. 2598 2599 This option is deprecated and should no longer be used. The new 2600 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2601 2602 ``lossy=on|off`` 2603 Enable lossy compression methods (gradient, JPEG, ...). If this 2604 option is set, VNC client may receive lossy framebuffer updates 2605 depending on its encoding settings. Enabling this option can 2606 save a lot of bandwidth at the expense of quality. 2607 2608 ``non-adaptive=on|off`` 2609 Disable adaptive encodings. Adaptive encodings are enabled by 2610 default. An adaptive encoding will try to detect frequently 2611 updated screen regions, and send updates in these regions using 2612 a lossy encoding (like JPEG). This can be really helpful to save 2613 bandwidth when playing videos. Disabling adaptive encodings 2614 restores the original static behavior of encodings like Tight. 2615 2616 ``share=[allow-exclusive|force-shared|ignore]`` 2617 Set display sharing policy. 'allow-exclusive' allows clients to 2618 ask for exclusive access. As suggested by the rfb spec this is 2619 implemented by dropping other connections. Connecting multiple 2620 clients in parallel requires all clients asking for a shared 2621 session (vncviewer: -shared switch). This is the default. 2622 'force-shared' disables exclusive client access. Useful for 2623 shared desktop sessions, where you don't want someone forgetting 2624 specify -shared disconnect everybody else. 'ignore' completely 2625 ignores the shared flag and allows everybody connect 2626 unconditionally. Doesn't conform to the rfb spec but is 2627 traditional QEMU behavior. 2628 2629 ``key-delay-ms`` 2630 Set keyboard delay, for key down and key up events, in 2631 milliseconds. Default is 10. Keyboards are low-bandwidth 2632 devices, so this slowdown can help the device and guest to keep 2633 up and not lose events in case events are arriving in bulk. 2634 Possible causes for the latter are flaky network connections, or 2635 scripts for automated testing. 2636 2637 ``audiodev=audiodev`` 2638 Use the specified audiodev when the VNC client requests audio 2639 transmission. When not using an -audiodev argument, this option 2640 must be omitted, otherwise is must be present and specify a 2641 valid audiodev. 2642 2643 ``power-control=on|off`` 2644 Permit the remote client to issue shutdown, reboot or reset power 2645 control requests. 2646ERST 2647 2648ARCHHEADING(, QEMU_ARCH_I386) 2649 2650ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2651 2652DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2653 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2654 QEMU_ARCH_I386) 2655SRST 2656``-win2k-hack`` 2657 Use it when installing Windows 2000 to avoid a disk full bug. After 2658 Windows 2000 is installed, you no longer need this option (this 2659 option slows down the IDE transfers). Synonym of ``-global 2660 ide-device.win2k-install-hack=on``. 2661ERST 2662 2663DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2664 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2665 QEMU_ARCH_I386) 2666SRST 2667``-no-fd-bootchk`` 2668 Disable boot signature checking for floppy disks in BIOS. May be 2669 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2670ERST 2671 2672DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2673 "-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" 2674 " ACPI table description\n", QEMU_ARCH_I386) 2675SRST 2676``-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]...]`` 2677 Add ACPI table with specified header fields and context from 2678 specified files. For file=, take whole ACPI table from the specified 2679 files, including all ACPI headers (possible overridden by other 2680 options). For data=, only data portion of the table is used, all 2681 header information is specified in the command line. If a SLIC table 2682 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2683 fields will override the same in the RSDT and the FADT (a.k.a. 2684 FACP), in order to ensure the field matches required by the 2685 Microsoft SLIC spec and the ACPI spec. 2686ERST 2687 2688DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2689 "-smbios file=binary\n" 2690 " load SMBIOS entry from binary file\n" 2691 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2692 " [,uefi=on|off]\n" 2693 " specify SMBIOS type 0 fields\n" 2694 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2695 " [,uuid=uuid][,sku=str][,family=str]\n" 2696 " specify SMBIOS type 1 fields\n" 2697 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2698 " [,asset=str][,location=str]\n" 2699 " specify SMBIOS type 2 fields\n" 2700 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2701 " [,sku=str]\n" 2702 " specify SMBIOS type 3 fields\n" 2703 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2704 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2705 " [,processor-family=%d,processor-id=%d]\n" 2706 " specify SMBIOS type 4 fields\n" 2707 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2708 " specify SMBIOS type 8 fields\n" 2709 "-smbios type=11[,value=str][,path=filename]\n" 2710 " specify SMBIOS type 11 fields\n" 2711 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2712 " [,asset=str][,part=str][,speed=%d]\n" 2713 " specify SMBIOS type 17 fields\n" 2714 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2715 " specify SMBIOS type 41 fields\n", 2716 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2717SRST 2718``-smbios file=binary`` 2719 Load SMBIOS entry from binary file. 2720 2721``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2722 Specify SMBIOS type 0 fields 2723 2724``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2725 Specify SMBIOS type 1 fields 2726 2727``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2728 Specify SMBIOS type 2 fields 2729 2730``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2731 Specify SMBIOS type 3 fields 2732 2733``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2734 Specify SMBIOS type 4 fields 2735 2736``-smbios type=9[,slot_designation=str][,slot_type=%d][,slot_data_bus_width=%d][,current_usage=%d][,slot_length=%d][,slot_id=%d][,slot_characteristics1=%d][,slot_characteristics12=%d][,pci_device=str]`` 2737 Specify SMBIOS type 9 fields 2738 2739``-smbios type=11[,value=str][,path=filename]`` 2740 Specify SMBIOS type 11 fields 2741 2742 This argument can be repeated multiple times, and values are added in the order they are parsed. 2743 Applications intending to use OEM strings data are encouraged to use their application name as 2744 a prefix for the value string. This facilitates passing information for multiple applications 2745 concurrently. 2746 2747 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2748 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2749 2750 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2751 the SMBIOS table in the order in which they appear. 2752 2753 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2754 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2755 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2756 data set, for example, by specifying the serial ID of a block device. 2757 2758 An example passing three strings is 2759 2760 .. parsed-literal:: 2761 2762 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2763 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2764 path=/some/file/with/oemstringsdata.txt 2765 2766 In the guest OS this is visible with the ``dmidecode`` command 2767 2768 .. parsed-literal:: 2769 2770 $ dmidecode -t 11 2771 Handle 0x0E00, DMI type 11, 5 bytes 2772 OEM Strings 2773 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2774 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2775 String 3: myapp:some extra data 2776 2777 2778``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2779 Specify SMBIOS type 17 fields 2780 2781``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2782 Specify SMBIOS type 41 fields 2783 2784 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2785 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2786 position on the PCI bus. 2787 2788 Here is an example of use: 2789 2790 .. parsed-literal:: 2791 2792 -netdev user,id=internet \\ 2793 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2794 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2795 2796 In the guest OS, the device should then appear as ``eno1``: 2797 2798 ..parsed-literal:: 2799 2800 $ ip -brief l 2801 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2802 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2803 2804 Currently, the PCI device has to be attached to the root bus. 2805 2806ERST 2807 2808DEFHEADING() 2809 2810DEFHEADING(Network options:) 2811 2812DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2813#ifdef CONFIG_SLIRP 2814 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2815 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2816 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2817 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2818 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2819#ifndef _WIN32 2820 "[,smb=dir[,smbserver=addr]]\n" 2821#endif 2822 " configure a user mode network backend with ID 'str',\n" 2823 " its DHCP server and optional services\n" 2824#endif 2825#ifdef _WIN32 2826 "-netdev tap,id=str,ifname=name\n" 2827 " configure a host TAP network backend with ID 'str'\n" 2828#else 2829 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2830 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2831 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2832 " [,poll-us=n]\n" 2833 " configure a host TAP network backend with ID 'str'\n" 2834 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2835 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2836 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2837 " to deconfigure it\n" 2838 " use '[down]script=no' to disable script execution\n" 2839 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2840 " configure it\n" 2841 " use 'fd=h' to connect to an already opened TAP interface\n" 2842 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2843 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2844 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2845 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2846 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2847 " use vhost=on to enable experimental in kernel accelerator\n" 2848 " (only has effect for virtio guests which use MSIX)\n" 2849 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2850 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2851 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2852 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2853 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2854 " spent on busy polling for vhost net\n" 2855 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2856 " configure a host TAP network backend with ID 'str' that is\n" 2857 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2858 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2859#endif 2860#ifdef __linux__ 2861 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2862 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2863 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2864 " [,rxcookie=rxcookie][,offset=offset]\n" 2865 " configure a network backend with ID 'str' connected to\n" 2866 " an Ethernet over L2TPv3 pseudowire.\n" 2867 " Linux kernel 3.3+ as well as most routers can talk\n" 2868 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2869 " VM to a router and even VM to Host. It is a nearly-universal\n" 2870 " standard (RFC3931). Note - this implementation uses static\n" 2871 " pre-configured tunnels (same as the Linux kernel).\n" 2872 " use 'src=' to specify source address\n" 2873 " use 'dst=' to specify destination address\n" 2874 " use 'udp=on' to specify udp encapsulation\n" 2875 " use 'srcport=' to specify source udp port\n" 2876 " use 'dstport=' to specify destination udp port\n" 2877 " use 'ipv6=on' to force v6\n" 2878 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2879 " well as a weak security measure\n" 2880 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2881 " use 'txcookie=0x012345678' to specify a txcookie\n" 2882 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2883 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2884 " use 'pincounter=on' to work around broken counter handling in peer\n" 2885 " use 'offset=X' to add an extra offset between header and data\n" 2886#endif 2887 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2888 " configure a network backend to connect to another network\n" 2889 " using a socket connection\n" 2890 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2891 " configure a network backend to connect to a multicast maddr and port\n" 2892 " use 'localaddr=addr' to specify the host address to send packets from\n" 2893 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2894 " configure a network backend to connect to another network\n" 2895 " using an UDP tunnel\n" 2896 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n" 2897 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2898 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2899 " configure a network backend to connect to another network\n" 2900 " using a socket connection in stream mode.\n" 2901 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2902 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2903 " configure a network backend to connect to a multicast maddr and port\n" 2904 " use ``local.host=addr`` to specify the host address to send packets from\n" 2905 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2906 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2907 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2908 " configure a network backend to connect to another network\n" 2909 " using an UDP tunnel\n" 2910#ifdef CONFIG_VDE 2911 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2912 " configure a network backend to connect to port 'n' of a vde switch\n" 2913 " running on host and listening for incoming connections on 'socketpath'.\n" 2914 " Use group 'groupname' and mode 'octalmode' to change default\n" 2915 " ownership and permissions for communication port.\n" 2916#endif 2917#ifdef CONFIG_NETMAP 2918 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2919 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2920 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2921 " netmap device, defaults to '/dev/netmap')\n" 2922#endif 2923#ifdef CONFIG_AF_XDP 2924 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2925 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2926 " attach to the existing network interface 'name' with AF_XDP socket\n" 2927 " use 'mode=MODE' to specify an XDP program attach mode\n" 2928 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2929 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2930 " with inhibit=on,\n" 2931 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2932 " added to a socket map in XDP program. One socket per queue.\n" 2933 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2934 " use 'start-queue=m' to specify the first queue that should be used\n" 2935#endif 2936#ifdef CONFIG_POSIX 2937 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2938 " configure a vhost-user network, backed by a chardev 'dev'\n" 2939#endif 2940#ifdef __linux__ 2941 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2942 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2943 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2944 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2945#endif 2946#ifdef CONFIG_VMNET 2947 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2948 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2949 " configure a vmnet network backend in host mode with ID 'str',\n" 2950 " isolate this interface from others with 'isolated',\n" 2951 " configure the address range and choose a subnet mask,\n" 2952 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2953 " vmnet-host interfaces within this isolated network\n" 2954 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2955 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2956 " configure a vmnet network backend in shared mode with ID 'str',\n" 2957 " configure the address range and choose a subnet mask,\n" 2958 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2959 " isolate this interface from others with 'isolated'\n" 2960 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2961 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2962 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2963 " isolate this interface from others with 'isolated'\n" 2964#endif 2965 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2966 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2967DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2968 "-nic [tap|bridge|" 2969#ifdef CONFIG_SLIRP 2970 "user|" 2971#endif 2972#ifdef __linux__ 2973 "l2tpv3|" 2974#endif 2975#ifdef CONFIG_VDE 2976 "vde|" 2977#endif 2978#ifdef CONFIG_NETMAP 2979 "netmap|" 2980#endif 2981#ifdef CONFIG_AF_XDP 2982 "af-xdp|" 2983#endif 2984#ifdef CONFIG_POSIX 2985 "vhost-user|" 2986#endif 2987#ifdef CONFIG_VMNET 2988 "vmnet-host|vmnet-shared|vmnet-bridged|" 2989#endif 2990 "socket][,option][,...][mac=macaddr]\n" 2991 " initialize an on-board / default host NIC (using MAC address\n" 2992 " macaddr) and connect it to the given host network backend\n" 2993 "-nic none use it alone to have zero network devices (the default is to\n" 2994 " provided a 'user' network connection)\n", 2995 QEMU_ARCH_ALL) 2996DEF("net", HAS_ARG, QEMU_OPTION_net, 2997 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2998 " configure or create an on-board (or machine default) NIC and\n" 2999 " connect it to hub 0 (please use -nic unless you need a hub)\n" 3000 "-net [" 3001#ifdef CONFIG_SLIRP 3002 "user|" 3003#endif 3004 "tap|" 3005 "bridge|" 3006#ifdef CONFIG_VDE 3007 "vde|" 3008#endif 3009#ifdef CONFIG_NETMAP 3010 "netmap|" 3011#endif 3012#ifdef CONFIG_AF_XDP 3013 "af-xdp|" 3014#endif 3015#ifdef CONFIG_VMNET 3016 "vmnet-host|vmnet-shared|vmnet-bridged|" 3017#endif 3018 "socket][,option][,option][,...]\n" 3019 " old way to initialize a host network interface\n" 3020 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3021SRST 3022``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3023 This option is a shortcut for configuring both the on-board 3024 (default) guest NIC hardware and the host network backend in one go. 3025 The host backend options are the same as with the corresponding 3026 ``-netdev`` options below. The guest NIC model can be set with 3027 ``model=modelname``. Use ``model=help`` to list the available device 3028 types. The hardware MAC address can be set with ``mac=macaddr``. 3029 3030 The following two example do exactly the same, to show how ``-nic`` 3031 can be used to shorten the command line length: 3032 3033 .. parsed-literal:: 3034 3035 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3036 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3037 3038``-nic none`` 3039 Indicate that no network devices should be configured. It is used to 3040 override the default configuration (default NIC with "user" host 3041 network backend) which is activated if no other networking options 3042 are provided. 3043 3044``-netdev user,id=id[,option][,option][,...]`` 3045 Configure user mode host network backend which requires no 3046 administrator privilege to run. Valid options are: 3047 3048 ``id=id`` 3049 Assign symbolic name for use in monitor commands. 3050 3051 ``ipv4=on|off and ipv6=on|off`` 3052 Specify that either IPv4 or IPv6 must be enabled. If neither is 3053 specified both protocols are enabled. 3054 3055 ``net=addr[/mask]`` 3056 Set IP network address the guest will see. Optionally specify 3057 the netmask, either in the form a.b.c.d or as number of valid 3058 top-most bits. Default is 10.0.2.0/24. 3059 3060 ``host=addr`` 3061 Specify the guest-visible address of the host. Default is the 3062 2nd IP in the guest network, i.e. x.x.x.2. 3063 3064 ``ipv6-net=addr[/int]`` 3065 Set IPv6 network address the guest will see (default is 3066 fec0::/64). The network prefix is given in the usual hexadecimal 3067 IPv6 address notation. The prefix size is optional, and is given 3068 as the number of valid top-most bits (default is 64). 3069 3070 ``ipv6-host=addr`` 3071 Specify the guest-visible IPv6 address of the host. Default is 3072 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3073 3074 ``restrict=on|off`` 3075 If this option is enabled, the guest will be isolated, i.e. it 3076 will not be able to contact the host and no guest IP packets 3077 will be routed over the host to the outside. This option does 3078 not affect any explicitly set forwarding rules. 3079 3080 ``hostname=name`` 3081 Specifies the client hostname reported by the built-in DHCP 3082 server. 3083 3084 ``dhcpstart=addr`` 3085 Specify the first of the 16 IPs the built-in DHCP server can 3086 assign. Default is the 15th to 31st IP in the guest network, 3087 i.e. x.x.x.15 to x.x.x.31. 3088 3089 ``dns=addr`` 3090 Specify the guest-visible address of the virtual nameserver. The 3091 address must be different from the host address. Default is the 3092 3rd IP in the guest network, i.e. x.x.x.3. 3093 3094 ``ipv6-dns=addr`` 3095 Specify the guest-visible address of the IPv6 virtual 3096 nameserver. The address must be different from the host address. 3097 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3098 3099 ``dnssearch=domain`` 3100 Provides an entry for the domain-search list sent by the 3101 built-in DHCP server. More than one domain suffix can be 3102 transmitted by specifying this option multiple times. If 3103 supported, this will cause the guest to automatically try to 3104 append the given domain suffix(es) in case a domain name can not 3105 be resolved. 3106 3107 Example: 3108 3109 .. parsed-literal:: 3110 3111 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3112 3113 ``domainname=domain`` 3114 Specifies the client domain name reported by the built-in DHCP 3115 server. 3116 3117 ``tftp=dir`` 3118 When using the user mode network stack, activate a built-in TFTP 3119 server. The files in dir will be exposed as the root of a TFTP 3120 server. The TFTP client on the guest must be configured in 3121 binary mode (use the command ``bin`` of the Unix TFTP client). 3122 The built-in TFTP server is read-only; it does not implement any 3123 command for writing files. QEMU will not write to this directory. 3124 3125 ``tftp-server-name=name`` 3126 In BOOTP reply, broadcast name as the "TFTP server name" 3127 (RFC2132 option 66). This can be used to advise the guest to 3128 load boot files or configurations from a different server than 3129 the host address. 3130 3131 ``bootfile=file`` 3132 When using the user mode network stack, broadcast file as the 3133 BOOTP filename. In conjunction with ``tftp``, this can be used 3134 to network boot a guest from a local directory. 3135 3136 Example (using pxelinux): 3137 3138 .. parsed-literal:: 3139 3140 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3141 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3142 3143 ``smb=dir[,smbserver=addr]`` 3144 When using the user mode network stack, activate a built-in SMB 3145 server so that Windows OSes can access to the host files in 3146 ``dir`` transparently. The IP address of the SMB server can be 3147 set to addr. By default the 4th IP in the guest network is used, 3148 i.e. x.x.x.4. 3149 3150 In the guest Windows OS, the line: 3151 3152 :: 3153 3154 10.0.2.4 smbserver 3155 3156 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3157 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3158 NT/2000). 3159 3160 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3161 3162 Note that a SAMBA server must be installed on the host OS. 3163 3164 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3165 Redirect incoming TCP or UDP connections to the host port 3166 hostport to the guest IP address guestaddr on guest port 3167 guestport. If guestaddr is not specified, its value is x.x.x.15 3168 (default first address given by the built-in DHCP server). By 3169 specifying hostaddr, the rule can be bound to a specific host 3170 interface. If no connection type is set, TCP is used. This 3171 option can be given multiple times. 3172 3173 For example, to redirect host X11 connection from screen 1 to 3174 guest screen 0, use the following: 3175 3176 .. parsed-literal:: 3177 3178 # on the host 3179 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3180 # this host xterm should open in the guest X11 server 3181 xterm -display :1 3182 3183 To redirect telnet connections from host port 5555 to telnet 3184 port on the guest, use the following: 3185 3186 .. parsed-literal:: 3187 3188 # on the host 3189 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3190 telnet localhost 5555 3191 3192 Then when you use on the host ``telnet localhost 5555``, you 3193 connect to the guest telnet server. 3194 3195 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3196 Forward guest TCP connections to the IP address server on port 3197 port to the character device dev or to a program executed by 3198 cmd:command which gets spawned for each connection. This option 3199 can be given multiple times. 3200 3201 You can either use a chardev directly and have that one used 3202 throughout QEMU's lifetime, like in the following example: 3203 3204 .. parsed-literal:: 3205 3206 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3207 # the guest accesses it 3208 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3209 3210 Or you can execute a command on every TCP connection established 3211 by the guest, so that QEMU behaves similar to an inetd process 3212 for that virtual server: 3213 3214 .. parsed-literal:: 3215 3216 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3217 # and connect the TCP stream to its stdin/stdout 3218 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3219 3220``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3221 Configure a host TAP network backend with ID id. 3222 3223 Use the network script file to configure it and the network script 3224 dfile to deconfigure it. If name is not provided, the OS 3225 automatically provides one. The default network configure script is 3226 ``/etc/qemu-ifup`` and the default network deconfigure script is 3227 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3228 disable script execution. 3229 3230 If running QEMU as an unprivileged user, use the network helper 3231 to configure the TAP interface and attach it to the bridge. 3232 The default network helper executable is 3233 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3234 ``br0``. 3235 3236 ``fd``\ =h can be used to specify the handle of an already opened 3237 host TAP interface. 3238 3239 Examples: 3240 3241 .. parsed-literal:: 3242 3243 #launch a QEMU instance with the default network script 3244 |qemu_system| linux.img -nic tap 3245 3246 .. parsed-literal:: 3247 3248 #launch a QEMU instance with two NICs, each one connected 3249 #to a TAP device 3250 |qemu_system| linux.img \\ 3251 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3252 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3253 3254 .. parsed-literal:: 3255 3256 #launch a QEMU instance with the default network helper to 3257 #connect a TAP device to bridge br0 3258 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3259 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3260 3261``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3262 Connect a host TAP network interface to a host bridge device. 3263 3264 Use the network helper helper to configure the TAP interface and 3265 attach it to the bridge. The default network helper executable is 3266 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3267 ``br0``. 3268 3269 Examples: 3270 3271 .. parsed-literal:: 3272 3273 #launch a QEMU instance with the default network helper to 3274 #connect a TAP device to bridge br0 3275 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3276 3277 .. parsed-literal:: 3278 3279 #launch a QEMU instance with the default network helper to 3280 #connect a TAP device to bridge qemubr0 3281 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3282 3283``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3284 This host network backend can be used to connect the guest's network 3285 to another QEMU virtual machine using a TCP socket connection. If 3286 ``listen`` is specified, QEMU waits for incoming connections on port 3287 (host is optional). ``connect`` is used to connect to another QEMU 3288 instance using the ``listen`` option. ``fd``\ =h specifies an 3289 already opened TCP socket. 3290 3291 Example: 3292 3293 .. parsed-literal:: 3294 3295 # launch a first QEMU instance 3296 |qemu_system| linux.img \\ 3297 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3298 -netdev socket,id=n1,listen=:1234 3299 # connect the network of this instance to the network of the first instance 3300 |qemu_system| linux.img \\ 3301 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3302 -netdev socket,id=n2,connect=127.0.0.1:1234 3303 3304``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3305 Configure a socket host network backend to share the guest's network 3306 traffic with another QEMU virtual machines using a UDP multicast 3307 socket, effectively making a bus for every QEMU with same multicast 3308 address maddr and port. NOTES: 3309 3310 1. Several QEMU can be running on different hosts and share same bus 3311 (assuming correct multicast setup for these hosts). 3312 3313 2. mcast support is compatible with User Mode Linux (argument 3314 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3315 3316 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3317 3318 Example: 3319 3320 .. parsed-literal:: 3321 3322 # launch one QEMU instance 3323 |qemu_system| linux.img \\ 3324 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3325 -netdev socket,id=n1,mcast=230.0.0.1:1234 3326 # launch another QEMU instance on same "bus" 3327 |qemu_system| linux.img \\ 3328 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3329 -netdev socket,id=n2,mcast=230.0.0.1:1234 3330 # launch yet another QEMU instance on same "bus" 3331 |qemu_system| linux.img \\ 3332 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3333 -netdev socket,id=n3,mcast=230.0.0.1:1234 3334 3335 Example (User Mode Linux compat.): 3336 3337 .. parsed-literal:: 3338 3339 # launch QEMU instance (note mcast address selected is UML's default) 3340 |qemu_system| linux.img \\ 3341 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3342 -netdev socket,id=n1,mcast=239.192.168.1:1102 3343 # launch UML 3344 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3345 3346 Example (send packets from host's 1.2.3.4): 3347 3348 .. parsed-literal:: 3349 3350 |qemu_system| linux.img \\ 3351 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3352 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3353 3354``-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]`` 3355 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3356 is a popular protocol to transport Ethernet (and other Layer 2) data 3357 frames between two systems. It is present in routers, firewalls and 3358 the Linux kernel (from version 3.3 onwards). 3359 3360 This transport allows a VM to communicate to another VM, router or 3361 firewall directly. 3362 3363 ``src=srcaddr`` 3364 source address (mandatory) 3365 3366 ``dst=dstaddr`` 3367 destination address (mandatory) 3368 3369 ``udp`` 3370 select udp encapsulation (default is ip). 3371 3372 ``srcport=srcport`` 3373 source udp port. 3374 3375 ``dstport=dstport`` 3376 destination udp port. 3377 3378 ``ipv6`` 3379 force v6, otherwise defaults to v4. 3380 3381 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3382 Cookies are a weak form of security in the l2tpv3 specification. 3383 Their function is mostly to prevent misconfiguration. By default 3384 they are 32 bit. 3385 3386 ``cookie64`` 3387 Set cookie size to 64 bit instead of the default 32 3388 3389 ``counter=off`` 3390 Force a 'cut-down' L2TPv3 with no counter as in 3391 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3392 3393 ``pincounter=on`` 3394 Work around broken counter handling in peer. This may also help 3395 on networks which have packet reorder. 3396 3397 ``offset=offset`` 3398 Add an extra offset between header and data 3399 3400 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3401 the bridge br-lan on the remote Linux host 1.2.3.4: 3402 3403 .. parsed-literal:: 3404 3405 # Setup tunnel on linux host using raw ip as encapsulation 3406 # on 1.2.3.4 3407 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3408 encap udp udp_sport 16384 udp_dport 16384 3409 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3410 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3411 ifconfig vmtunnel0 mtu 1500 3412 ifconfig vmtunnel0 up 3413 brctl addif br-lan vmtunnel0 3414 3415 3416 # on 4.3.2.1 3417 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3418 3419 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3420 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3421 3422``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3423 Configure VDE backend to connect to PORT n of a vde switch running 3424 on host and listening for incoming connections on socketpath. Use 3425 GROUP groupname and MODE octalmode to change default ownership and 3426 permissions for communication port. This option is only available if 3427 QEMU has been compiled with vde support enabled. 3428 3429 Example: 3430 3431 .. parsed-literal:: 3432 3433 # launch vde switch 3434 vde_switch -F -sock /tmp/myswitch 3435 # launch QEMU instance 3436 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3437 3438``-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off][,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]`` 3439 Configure AF_XDP backend to connect to a network interface 'name' 3440 using AF_XDP socket. A specific program attach mode for a default 3441 XDP program can be forced with 'mode', defaults to best-effort, 3442 where the likely most performant mode will be in use. Number of queues 3443 'n' should generally match the number or queues in the interface, 3444 defaults to 1. Traffic arriving on non-configured device queues will 3445 not be delivered to the network backend. 3446 3447 .. parsed-literal:: 3448 3449 # set number of queues to 4 3450 ethtool -L eth0 combined 4 3451 # launch QEMU instance 3452 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3453 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3454 3455 'start-queue' option can be specified if a particular range of queues 3456 [m, m + n] should be in use. For example, this is may be necessary in 3457 order to use certain NICs in native mode. Kernel allows the driver to 3458 create a separate set of XDP queues on top of regular ones, and only 3459 these queues can be used for AF_XDP sockets. NICs that work this way 3460 may also require an additional traffic redirection with ethtool to these 3461 special queues. 3462 3463 .. parsed-literal:: 3464 3465 # set number of queues to 1 3466 ethtool -L eth0 combined 1 3467 # redirect all the traffic to the second queue (id: 1) 3468 # note: drivers may require non-empty key/mask pair. 3469 ethtool -N eth0 flow-type ether \\ 3470 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3471 ethtool -N eth0 flow-type ether \\ 3472 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3473 # launch QEMU instance 3474 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3475 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3476 3477 XDP program can also be loaded externally. In this case 'inhibit' option 3478 should be set to 'on' and 'sock-fds' provided with file descriptors for 3479 already open but not bound XDP sockets already added to a socket map for 3480 corresponding queues. One socket per queue. 3481 3482 .. parsed-literal:: 3483 3484 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3485 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3486 3487``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3488 Establish a vhost-user netdev, backed by a chardev id. The chardev 3489 should be a unix domain socket backed one. The vhost-user uses a 3490 specifically defined protocol to pass vhost ioctl replacement 3491 messages to an application on the other end of the socket. On 3492 non-MSIX guests, the feature can be forced with vhostforce. Use 3493 'queues=n' to specify the number of queues to be created for 3494 multiqueue vhost-user. 3495 3496 Example: 3497 3498 :: 3499 3500 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3501 -numa node,memdev=mem \ 3502 -chardev socket,id=chr0,path=/path/to/socket \ 3503 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3504 -device virtio-net-pci,netdev=net0 3505 3506``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3507 Establish a vhost-vdpa netdev. 3508 3509 vDPA device is a device that uses a datapath which complies with 3510 the virtio specifications with a vendor specific control path. 3511 vDPA devices can be both physically located on the hardware or 3512 emulated by software. 3513 3514``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3515 Create a hub port on the emulated hub with ID hubid. 3516 3517 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3518 instead of a single netdev. Alternatively, you can also connect the 3519 hubport to another netdev with ID nd by using the ``netdev=nd`` 3520 option. 3521 3522``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3523 Legacy option to configure or create an on-board (or machine 3524 default) Network Interface Card(NIC) and connect it either to the 3525 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3526 If model is omitted, then the default NIC model associated with the 3527 machine type is used. Note that the default NIC model may change in 3528 future QEMU releases, so it is highly recommended to always specify 3529 a model. Optionally, the MAC address can be changed to mac, the 3530 device address set to addr (PCI cards only), and a name can be 3531 assigned for use in monitor commands. Optionally, for PCI cards, you 3532 can specify the number v of MSI-X vectors that the card should have; 3533 this option currently only affects virtio cards; set v = 0 to 3534 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3535 created. QEMU can emulate several different models of network card. 3536 Use ``-net nic,model=help`` for a list of available devices for your 3537 target. 3538 3539``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3540 Configure a host network backend (with the options corresponding to 3541 the same ``-netdev`` option) and connect it to the emulated hub 0 3542 (the default hub). Use name to specify the name of the hub port. 3543ERST 3544 3545DEFHEADING() 3546 3547DEFHEADING(Character device options:) 3548 3549DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3550 "-chardev help\n" 3551 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3552 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3553 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3554 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3555 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3556 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3557 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3558 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3559 " [,logfile=PATH][,logappend=on|off]\n" 3560 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3561 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3562 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3563 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3564 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3565 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3566#ifdef _WIN32 3567 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3568 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3569#else 3570 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3571 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3572#endif 3573#ifdef CONFIG_BRLAPI 3574 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3575#endif 3576#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3577 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3578 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3579#endif 3580#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3581 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3582#endif 3583#if defined(CONFIG_SPICE) 3584 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3585 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3586#endif 3587 , QEMU_ARCH_ALL 3588) 3589 3590SRST 3591The general form of a character device option is: 3592 3593``-chardev backend,id=id[,mux=on|off][,options]`` 3594 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3595 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3596 ``pty``, ``stdio``, ``braille``, ``parallel``, 3597 ``spicevmc``, ``spiceport``. The specific backend will determine the 3598 applicable options. 3599 3600 Use ``-chardev help`` to print all available chardev backend types. 3601 3602 All devices must have an id, which can be any string up to 127 3603 characters long. It is used to uniquely identify this device in 3604 other command line directives. 3605 3606 A character device may be used in multiplexing mode by multiple 3607 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3608 a "1:N" device, and here the "1" end is your specified chardev 3609 backend, and the "N" end is the various parts of QEMU that can talk 3610 to a chardev. If you create a chardev with ``id=myid`` and 3611 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3612 and you can then configure multiple front ends to use that chardev 3613 ID for their input/output. Up to four different front ends can be 3614 connected to a single multiplexed chardev. (Without multiplexing 3615 enabled, a chardev can only be used by a single front end.) For 3616 instance you could use this to allow a single stdio chardev to be 3617 used by two serial ports and the QEMU monitor: 3618 3619 :: 3620 3621 -chardev stdio,mux=on,id=char0 \ 3622 -mon chardev=char0,mode=readline \ 3623 -serial chardev:char0 \ 3624 -serial chardev:char0 3625 3626 You can have more than one multiplexer in a system configuration; 3627 for instance you could have a TCP port multiplexed between UART 0 3628 and UART 1, and stdio multiplexed between the QEMU monitor and a 3629 parallel port: 3630 3631 :: 3632 3633 -chardev stdio,mux=on,id=char0 \ 3634 -mon chardev=char0,mode=readline \ 3635 -parallel chardev:char0 \ 3636 -chardev tcp,...,mux=on,id=char1 \ 3637 -serial chardev:char1 \ 3638 -serial chardev:char1 3639 3640 When you're using a multiplexed character device, some escape 3641 sequences are interpreted in the input. See the chapter about 3642 :ref:`keys in the character backend multiplexer` in the 3643 System Emulation Users Guide for more details. 3644 3645 Note that some other command line options may implicitly create 3646 multiplexed character backends; for instance ``-serial mon:stdio`` 3647 creates a multiplexed stdio backend connected to the serial port and 3648 the QEMU monitor, and ``-nographic`` also multiplexes the console 3649 and the monitor to stdio. 3650 3651 There is currently no support for multiplexing in the other 3652 direction (where a single QEMU front end takes input and output from 3653 multiple chardevs). 3654 3655 Every backend supports the ``logfile`` option, which supplies the 3656 path to a file to record all data transmitted via the backend. The 3657 ``logappend`` option controls whether the log file will be truncated 3658 or appended to when opened. 3659 3660The available backends are: 3661 3662``-chardev null,id=id`` 3663 A void device. This device will not emit any data, and will drop any 3664 data it receives. The null backend does not take any options. 3665 3666``-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]`` 3667 Create a two-way stream socket, which can be either a TCP or a unix 3668 socket. A unix socket will be created if ``path`` is specified. 3669 Behaviour is undefined if TCP options are specified for a unix 3670 socket. 3671 3672 ``server=on|off`` specifies that the socket shall be a listening socket. 3673 3674 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3675 to connect to a listening socket. 3676 3677 ``telnet=on|off`` specifies that traffic on the socket should interpret 3678 telnet escape sequences. 3679 3680 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3681 communication. 3682 3683 ``reconnect`` sets the timeout for reconnecting on non-server 3684 sockets when the remote end goes away. qemu will delay this many 3685 seconds and then attempt to reconnect. Zero disables reconnecting, 3686 and is the default. 3687 3688 ``tls-creds`` requests enablement of the TLS protocol for 3689 encryption, and specifies the id of the TLS credentials to use for 3690 the handshake. The credentials must be previously created with the 3691 ``-object tls-creds`` argument. 3692 3693 ``tls-auth`` provides the ID of the QAuthZ authorization object 3694 against which the client's x509 distinguished name will be 3695 validated. This object is only resolved at time of use, so can be 3696 deleted and recreated on the fly while the chardev server is active. 3697 If missing, it will default to denying access. 3698 3699 TCP and unix socket options are given below: 3700 3701 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3702 ``host`` for a listening socket specifies the local address to 3703 be bound. For a connecting socket species the remote host to 3704 connect to. ``host`` is optional for listening sockets. If not 3705 specified it defaults to ``0.0.0.0``. 3706 3707 ``port`` for a listening socket specifies the local port to be 3708 bound. For a connecting socket specifies the port on the remote 3709 host to connect to. ``port`` can be given as either a port 3710 number or a service name. ``port`` is required. 3711 3712 ``to`` is only relevant to listening sockets. If it is 3713 specified, and ``port`` cannot be bound, QEMU will attempt to 3714 bind to subsequent ports up to and including ``to`` until it 3715 succeeds. ``to`` must be specified as a port number. 3716 3717 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3718 or IPv6 must be used. If neither is specified the socket may 3719 use either protocol. 3720 3721 ``nodelay=on|off`` disables the Nagle algorithm. 3722 3723 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3724 ``path`` specifies the local path of the unix socket. ``path`` 3725 is required. 3726 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3727 rather than the filesystem. Optional, defaults to false. 3728 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3729 rather than the full sun_path length. Optional, defaults to true. 3730 3731``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3732 Sends all traffic from the guest to a remote host over UDP. 3733 3734 ``host`` specifies the remote host to connect to. If not specified 3735 it defaults to ``localhost``. 3736 3737 ``port`` specifies the port on the remote host to connect to. 3738 ``port`` is required. 3739 3740 ``localaddr`` specifies the local address to bind to. If not 3741 specified it defaults to ``0.0.0.0``. 3742 3743 ``localport`` specifies the local port to bind to. If not specified 3744 any available local port will be used. 3745 3746 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3747 If neither is specified the device may use either protocol. 3748 3749``-chardev msmouse,id=id`` 3750 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3751 does not take any options. 3752 3753``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3754 Connect to a QEMU text console. ``vc`` may optionally be given a 3755 specific size. 3756 3757 ``width`` and ``height`` specify the width and height respectively 3758 of the console, in pixels. 3759 3760 ``cols`` and ``rows`` specify that the console be sized to fit a 3761 text console with the given dimensions. 3762 3763``-chardev ringbuf,id=id[,size=size]`` 3764 Create a ring buffer with fixed size ``size``. size must be a power 3765 of two and defaults to ``64K``. 3766 3767``-chardev file,id=id,path=path[,input-path=input-path]`` 3768 Log all traffic received from the guest to a file. 3769 3770 ``path`` specifies the path of the file to be opened. This file will 3771 be created if it does not already exist, and overwritten if it does. 3772 ``path`` is required. 3773 3774 If ``input-path`` is specified, this is the path of a second file 3775 which will be used for input. If ``input-path`` is not specified, 3776 no input will be available from the chardev. 3777 3778 Note that ``input-path`` is not supported on Windows hosts. 3779 3780``-chardev pipe,id=id,path=path`` 3781 Create a two-way connection to the guest. The behaviour differs 3782 slightly between Windows hosts and other hosts: 3783 3784 On Windows, a single duplex pipe will be created at 3785 ``\\.pipe\path``. 3786 3787 On other hosts, 2 pipes will be created called ``path.in`` and 3788 ``path.out``. Data written to ``path.in`` will be received by the 3789 guest. Data written by the guest can be read from ``path.out``. QEMU 3790 will not create these fifos, and requires them to be present. 3791 3792 ``path`` forms part of the pipe path as described above. ``path`` is 3793 required. 3794 3795``-chardev console,id=id`` 3796 Send traffic from the guest to QEMU's standard output. ``console`` 3797 does not take any options. 3798 3799 ``console`` is only available on Windows hosts. 3800 3801``-chardev serial,id=id,path=path`` 3802 Send traffic from the guest to a serial device on the host. 3803 3804 On Unix hosts serial will actually accept any tty device, not only 3805 serial lines. 3806 3807 ``path`` specifies the name of the serial device to open. 3808 3809``-chardev pty,id=id`` 3810 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3811 does not take any options. 3812 3813 ``pty`` is not available on Windows hosts. 3814 3815``-chardev stdio,id=id[,signal=on|off]`` 3816 Connect to standard input and standard output of the QEMU process. 3817 3818 ``signal`` controls if signals are enabled on the terminal, that 3819 includes exiting QEMU with the key sequence Control-c. This option 3820 is enabled by default, use ``signal=off`` to disable it. 3821 3822``-chardev braille,id=id`` 3823 Connect to a local BrlAPI server. ``braille`` does not take any 3824 options. 3825 3826``-chardev parallel,id=id,path=path`` 3827 \ 3828 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3829 hosts. 3830 3831 Connect to a local parallel port. 3832 3833 ``path`` specifies the path to the parallel port device. ``path`` is 3834 required. 3835 3836``-chardev spicevmc,id=id,debug=debug,name=name`` 3837 ``spicevmc`` is only available when spice support is built in. 3838 3839 ``debug`` debug level for spicevmc 3840 3841 ``name`` name of spice channel to connect to 3842 3843 Connect to a spice virtual machine channel, such as vdiport. 3844 3845``-chardev spiceport,id=id,debug=debug,name=name`` 3846 ``spiceport`` is only available when spice support is built in. 3847 3848 ``debug`` debug level for spicevmc 3849 3850 ``name`` name of spice port to connect to 3851 3852 Connect to a spice port, allowing a Spice client to handle the 3853 traffic identified by a name (preferably a fqdn). 3854ERST 3855 3856DEFHEADING() 3857 3858#ifdef CONFIG_TPM 3859DEFHEADING(TPM device options:) 3860 3861DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3862 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3863 " use path to provide path to a character device; default is /dev/tpm0\n" 3864 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3865 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3866 "-tpmdev emulator,id=id,chardev=dev\n" 3867 " configure the TPM device using chardev backend\n", 3868 QEMU_ARCH_ALL) 3869SRST 3870The general form of a TPM device option is: 3871 3872``-tpmdev backend,id=id[,options]`` 3873 The specific backend type will determine the applicable options. The 3874 ``-tpmdev`` option creates the TPM backend and requires a 3875 ``-device`` option that specifies the TPM frontend interface model. 3876 3877 Use ``-tpmdev help`` to print all available TPM backend types. 3878 3879The available backends are: 3880 3881``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3882 (Linux-host only) Enable access to the host's TPM using the 3883 passthrough driver. 3884 3885 ``path`` specifies the path to the host's TPM device, i.e., on a 3886 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3887 default ``/dev/tpm0`` is used. 3888 3889 ``cancel-path`` specifies the path to the host TPM device's sysfs 3890 entry allowing for cancellation of an ongoing TPM command. 3891 ``cancel-path`` is optional and by default QEMU will search for the 3892 sysfs entry to use. 3893 3894 Some notes about using the host's TPM with the passthrough driver: 3895 3896 The TPM device accessed by the passthrough driver must not be used 3897 by any other application on the host. 3898 3899 Since the host's firmware (BIOS/UEFI) has already initialized the 3900 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3901 the TPM again and may therefore not show a TPM-specific menu that 3902 would otherwise allow the user to configure the TPM, e.g., allow the 3903 user to enable/disable or activate/deactivate the TPM. Further, if 3904 TPM ownership is released from within a VM then the host's TPM will 3905 get disabled and deactivated. To enable and activate the TPM again 3906 afterwards, the host has to be rebooted and the user is required to 3907 enter the firmware's menu to enable and activate the TPM. If the TPM 3908 is left disabled and/or deactivated most TPM commands will fail. 3909 3910 To create a passthrough TPM use the following two options: 3911 3912 :: 3913 3914 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3915 3916 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3917 ``tpmdev=tpm0`` in the device option. 3918 3919``-tpmdev emulator,id=id,chardev=dev`` 3920 (Linux-host only) Enable access to a TPM emulator using Unix domain 3921 socket based chardev backend. 3922 3923 ``chardev`` specifies the unique ID of a character device backend 3924 that provides connection to the software TPM server. 3925 3926 To create a TPM emulator backend device with chardev socket backend: 3927 3928 :: 3929 3930 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3931ERST 3932 3933DEFHEADING() 3934 3935#endif 3936 3937DEFHEADING(Boot Image or Kernel specific:) 3938SRST 3939There are broadly 4 ways you can boot a system with QEMU. 3940 3941 - specify a firmware and let it control finding a kernel 3942 - specify a firmware and pass a hint to the kernel to boot 3943 - direct kernel image boot 3944 - manually load files into the guest's address space 3945 3946The third method is useful for quickly testing kernels but as there is 3947no firmware to pass configuration information to the kernel the 3948hardware must either be probeable, the kernel built for the exact 3949configuration or passed some configuration data (e.g. a DTB blob) 3950which tells the kernel what drivers it needs. This exact details are 3951often hardware specific. 3952 3953The final method is the most generic way of loading images into the 3954guest address space and used mostly for ``bare metal`` type 3955development where the reset vectors of the processor are taken into 3956account. 3957 3958ERST 3959 3960SRST 3961 3962For x86 machines and some other architectures ``-bios`` will generally 3963do the right thing with whatever it is given. For other machines the 3964more strict ``-pflash`` option needs an image that is sized for the 3965flash device for the given machine type. 3966 3967Please see the :ref:`system-targets-ref` section of the manual for 3968more detailed documentation. 3969 3970ERST 3971 3972DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3973 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3974SRST 3975``-bios file`` 3976 Set the filename for the BIOS. 3977ERST 3978 3979DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3980 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3981SRST 3982``-pflash file`` 3983 Use file as a parallel flash image. 3984ERST 3985 3986SRST 3987 3988The kernel options were designed to work with Linux kernels although 3989other things (like hypervisors) can be packaged up as a kernel 3990executable image. The exact format of a executable image is usually 3991architecture specific. 3992 3993The way in which the kernel is started (what address it is loaded at, 3994what if any information is passed to it via CPU registers, the state 3995of the hardware when it is started, and so on) is also architecture 3996specific. Typically it follows the specification laid down by the 3997Linux kernel for how kernels for that architecture must be started. 3998 3999ERST 4000 4001DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 4002 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 4003SRST 4004``-kernel bzImage`` 4005 Use bzImage as kernel image. The kernel can be either a Linux kernel 4006 or in multiboot format. 4007ERST 4008 4009DEF("append", HAS_ARG, QEMU_OPTION_append, \ 4010 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 4011SRST 4012``-append cmdline`` 4013 Use cmdline as kernel command line 4014ERST 4015 4016DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4017 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4018SRST(initrd) 4019 4020``-initrd file`` 4021 Use file as initial ram disk. 4022 4023``-initrd "file1 arg=foo,file2"`` 4024 This syntax is only available with multiboot. 4025 4026 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4027 first module. Commas can be provided in module parameters by doubling 4028 them on the command line to escape them: 4029 4030``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4031 Multiboot only. Use bzImage as the first module with 4032 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4033 and initrd.img as the second module. 4034 4035ERST 4036 4037DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4038 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4039SRST 4040``-dtb file`` 4041 Use file as a device tree binary (dtb) image and pass it to the 4042 kernel on boot. 4043ERST 4044 4045SRST 4046 4047Finally you can also manually load images directly into the address 4048space of the guest. This is most useful for developers who already 4049know the layout of their guest and take care to ensure something sane 4050will happen when the reset vector executes. 4051 4052The generic loader can be invoked by using the loader device: 4053 4054``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4055 4056there is also the guest loader which operates in a similar way but 4057tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4058the guest image is: 4059 4060``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4061 4062ERST 4063 4064DEFHEADING() 4065 4066DEFHEADING(Debug/Expert options:) 4067 4068DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4069 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4070 " Policy for handling deprecated management interfaces\n" 4071 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4072 " Policy for handling unstable management interfaces\n", 4073 QEMU_ARCH_ALL) 4074SRST 4075``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4076 Set policy for handling deprecated management interfaces (experimental): 4077 4078 ``deprecated-input=accept`` (default) 4079 Accept deprecated commands and arguments 4080 ``deprecated-input=reject`` 4081 Reject deprecated commands and arguments 4082 ``deprecated-input=crash`` 4083 Crash on deprecated commands and arguments 4084 ``deprecated-output=accept`` (default) 4085 Emit deprecated command results and events 4086 ``deprecated-output=hide`` 4087 Suppress deprecated command results and events 4088 4089 Limitation: covers only syntactic aspects of QMP. 4090 4091``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4092 Set policy for handling unstable management interfaces (experimental): 4093 4094 ``unstable-input=accept`` (default) 4095 Accept unstable commands and arguments 4096 ``unstable-input=reject`` 4097 Reject unstable commands and arguments 4098 ``unstable-input=crash`` 4099 Crash on unstable commands and arguments 4100 ``unstable-output=accept`` (default) 4101 Emit unstable command results and events 4102 ``unstable-output=hide`` 4103 Suppress unstable command results and events 4104 4105 Limitation: covers only syntactic aspects of QMP. 4106ERST 4107 4108DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4109 "-fw_cfg [name=]<name>,file=<file>\n" 4110 " add named fw_cfg entry with contents from file\n" 4111 "-fw_cfg [name=]<name>,string=<str>\n" 4112 " add named fw_cfg entry with contents from string\n", 4113 QEMU_ARCH_ALL) 4114SRST 4115``-fw_cfg [name=]name,file=file`` 4116 Add named fw\_cfg entry with contents from file file. 4117 If the filename contains comma, you must double it (for instance, 4118 "file=my,,file" to use file "my,file"). 4119 4120``-fw_cfg [name=]name,string=str`` 4121 Add named fw\_cfg entry with contents from string str. 4122 If the string contains comma, you must double it (for instance, 4123 "string=my,,string" to use file "my,string"). 4124 4125 The terminating NUL character of the contents of str will not be 4126 included as part of the fw\_cfg item data. To insert contents with 4127 embedded NUL characters, you have to use the file parameter. 4128 4129 The fw\_cfg entries are passed by QEMU through to the guest. 4130 4131 Example: 4132 4133 :: 4134 4135 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4136 4137 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4138 from ./my\_blob.bin. 4139ERST 4140 4141DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4142 "-serial dev redirect the serial port to char device 'dev'\n", 4143 QEMU_ARCH_ALL) 4144SRST 4145``-serial dev`` 4146 Redirect the virtual serial port to host character device dev. The 4147 default device is ``vc`` in graphical mode and ``stdio`` in non 4148 graphical mode. 4149 4150 This option can be used several times to simulate multiple serial 4151 ports. 4152 4153 You can use ``-serial none`` to suppress the creation of default 4154 serial devices. 4155 4156 Available character devices are: 4157 4158 ``vc[:WxH]`` 4159 Virtual console. Optionally, a width and height can be given in 4160 pixel with 4161 4162 :: 4163 4164 vc:800x600 4165 4166 It is also possible to specify width or height in characters: 4167 4168 :: 4169 4170 vc:80Cx24C 4171 4172 ``pty`` 4173 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4174 4175 ``none`` 4176 No device is allocated. Note that for machine types which 4177 emulate systems where a serial device is always present in 4178 real hardware, this may be equivalent to the ``null`` option, 4179 in that the serial device is still present but all output 4180 is discarded. For boards where the number of serial ports is 4181 truly variable, this suppresses the creation of the device. 4182 4183 ``null`` 4184 A guest will see the UART or serial device as present in the 4185 machine, but all output is discarded, and there is no input. 4186 Conceptually equivalent to redirecting the output to ``/dev/null``. 4187 4188 ``chardev:id`` 4189 Use a named character device defined with the ``-chardev`` 4190 option. 4191 4192 ``/dev/XXX`` 4193 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4194 port parameters are set according to the emulated ones. 4195 4196 ``/dev/parportN`` 4197 [Linux only, parallel port only] Use host parallel port N. 4198 Currently SPP and EPP parallel port features can be used. 4199 4200 ``file:filename`` 4201 Write output to filename. No character can be read. 4202 4203 ``stdio`` 4204 [Unix only] standard input/output 4205 4206 ``pipe:filename`` 4207 name pipe filename 4208 4209 ``COMn`` 4210 [Windows only] Use host serial port n 4211 4212 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4213 This implements UDP Net Console. When remote\_host or src\_ip 4214 are not specified they default to ``0.0.0.0``. When not using a 4215 specified src\_port a random port is automatically chosen. 4216 4217 If you just want a simple readonly console you can use 4218 ``netcat`` or ``nc``, by starting QEMU with: 4219 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4220 QEMU writes something to that port it will appear in the 4221 netconsole session. 4222 4223 If you plan to send characters back via netconsole or you want 4224 to stop and start QEMU a lot of times, you should have QEMU use 4225 the same source port each time by using something like ``-serial 4226 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4227 version of netcat which can listen to a TCP port and send and 4228 receive characters via udp. If you have a patched version of 4229 netcat which activates telnet remote echo and single char 4230 transfer, then you can use the following options to set up a 4231 netcat redirector to allow telnet on port 5555 to access the 4232 QEMU port. 4233 4234 ``QEMU Options:`` 4235 -serial udp::4555@:4556 4236 4237 ``netcat options:`` 4238 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4239 4240 ``telnet options:`` 4241 localhost 5555 4242 4243 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4244 The TCP Net Console has two modes of operation. It can send the 4245 serial I/O to a location or wait for a connection from a 4246 location. By default the TCP Net Console is sent to host at the 4247 port. If you use the ``server=on`` option QEMU will wait for a client 4248 socket application to connect to the port before continuing, 4249 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4250 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4251 option only applies if ``server=no`` is set, if the connection goes 4252 down it will attempt to reconnect at the given interval. If host 4253 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4254 time is accepted. You can use ``telnet=on`` to connect to the 4255 corresponding character device. 4256 4257 ``Example to send tcp console to 192.168.0.2 port 4444`` 4258 -serial tcp:192.168.0.2:4444 4259 4260 ``Example to listen and wait on port 4444 for connection`` 4261 -serial tcp::4444,server=on 4262 4263 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4264 -serial tcp:192.168.0.100:4444,server=on,wait=off 4265 4266 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4267 The telnet protocol is used instead of raw tcp sockets. The 4268 options work the same as if you had specified ``-serial tcp``. 4269 The difference is that the port acts like a telnet server or 4270 client using telnet option negotiation. This will also allow you 4271 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4272 supports sending the break sequence. Typically in unix telnet 4273 you do it with Control-] and then type "send break" followed by 4274 pressing the enter key. 4275 4276 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4277 The WebSocket protocol is used instead of raw tcp socket. The 4278 port acts as a WebSocket server. Client mode is not supported. 4279 4280 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4281 A unix domain socket is used instead of a tcp socket. The option 4282 works the same as if you had specified ``-serial tcp`` except 4283 the unix domain socket path is used for connections. 4284 4285 ``mon:dev_string`` 4286 This is a special option to allow the monitor to be multiplexed 4287 onto another serial port. The monitor is accessed with key 4288 sequence of Control-a and then pressing c. dev\_string should be 4289 any one of the serial devices specified above. An example to 4290 multiplex the monitor onto a telnet server listening on port 4291 4444 would be: 4292 4293 ``-serial mon:telnet::4444,server=on,wait=off`` 4294 4295 When the monitor is multiplexed to stdio in this way, Ctrl+C 4296 will not terminate QEMU any more but will be passed to the guest 4297 instead. 4298 4299 ``braille`` 4300 Braille device. This will use BrlAPI to display the braille 4301 output on a real or fake device. 4302 4303 ``msmouse`` 4304 Three button serial mouse. Configure the guest to use Microsoft 4305 protocol. 4306ERST 4307 4308DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4309 "-parallel dev redirect the parallel port to char device 'dev'\n", 4310 QEMU_ARCH_ALL) 4311SRST 4312``-parallel dev`` 4313 Redirect the virtual parallel port to host device dev (same devices 4314 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4315 to use hardware devices connected on the corresponding host parallel 4316 port. 4317 4318 This option can be used several times to simulate up to 3 parallel 4319 ports. 4320 4321 Use ``-parallel none`` to disable all parallel ports. 4322ERST 4323 4324DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4325 "-monitor dev redirect the monitor to char device 'dev'\n", 4326 QEMU_ARCH_ALL) 4327SRST 4328``-monitor dev`` 4329 Redirect the monitor to host device dev (same devices as the serial 4330 port). The default device is ``vc`` in graphical mode and ``stdio`` 4331 in non graphical mode. Use ``-monitor none`` to disable the default 4332 monitor. 4333ERST 4334DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4335 "-qmp dev like -monitor but opens in 'control' mode\n", 4336 QEMU_ARCH_ALL) 4337SRST 4338``-qmp dev`` 4339 Like ``-monitor`` but opens in 'control' mode. For example, to make 4340 QMP available on localhost port 4444:: 4341 4342 -qmp tcp:localhost:4444,server=on,wait=off 4343 4344 Not all options are configurable via this syntax; for maximum 4345 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4346 4347ERST 4348DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4349 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4350 QEMU_ARCH_ALL) 4351SRST 4352``-qmp-pretty dev`` 4353 Like ``-qmp`` but uses pretty JSON formatting. 4354ERST 4355 4356DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4357 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4358SRST 4359``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4360 Set up a monitor connected to the chardev ``name``. 4361 QEMU supports two monitors: the Human Monitor Protocol 4362 (HMP; for human interaction), and the QEMU Monitor Protocol 4363 (QMP; a JSON RPC-style protocol). 4364 The default is HMP; ``mode=control`` selects QMP instead. 4365 ``pretty`` is only valid when ``mode=control``, 4366 turning on JSON pretty printing to ease 4367 human reading and debugging. 4368 4369 For example:: 4370 4371 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4372 -mon chardev=mon1,mode=control,pretty=on 4373 4374 enables the QMP monitor on localhost port 4444 with pretty-printing. 4375ERST 4376 4377DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4378 "-debugcon dev redirect the debug console to char device 'dev'\n", 4379 QEMU_ARCH_ALL) 4380SRST 4381``-debugcon dev`` 4382 Redirect the debug console to host device dev (same devices as the 4383 serial port). The debug console is an I/O port which is typically 4384 port 0xe9; writing to that I/O port sends output to this device. The 4385 default device is ``vc`` in graphical mode and ``stdio`` in non 4386 graphical mode. 4387ERST 4388 4389DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4390 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4391SRST 4392``-pidfile file`` 4393 Store the QEMU process PID in file. It is useful if you launch QEMU 4394 from a script. 4395ERST 4396 4397DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4398 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4399 QEMU_ARCH_ALL) 4400SRST 4401``--preconfig`` 4402 Pause QEMU for interactive configuration before the machine is 4403 created, which allows querying and configuring properties that will 4404 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4405 exit the preconfig state and move to the next state (i.e. run guest 4406 if -S isn't used or pause the second time if -S is used). This 4407 option is experimental. 4408ERST 4409 4410DEF("S", 0, QEMU_OPTION_S, \ 4411 "-S freeze CPU at startup (use 'c' to start execution)\n", 4412 QEMU_ARCH_ALL) 4413SRST 4414``-S`` 4415 Do not start CPU at startup (you must type 'c' in the monitor). 4416ERST 4417 4418DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4419 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4420 " run qemu with overcommit hints\n" 4421 " mem-lock=on|off controls memory lock support (default: off)\n" 4422 " cpu-pm=on|off controls cpu power management (default: off)\n", 4423 QEMU_ARCH_ALL) 4424SRST 4425``-overcommit mem-lock=on|off`` 4426 \ 4427``-overcommit cpu-pm=on|off`` 4428 Run qemu with hints about host resource overcommit. The default is 4429 to assume that host overcommits all resources. 4430 4431 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4432 (disabled by default). This works when host memory is not 4433 overcommitted and reduces the worst-case latency for guest. 4434 4435 Guest ability to manage power state of host cpus (increasing latency 4436 for other processes on the same host cpu, but decreasing latency for 4437 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4438 works best when host CPU is not overcommitted. When used, host 4439 estimates of CPU cycle and power utilization will be incorrect, not 4440 taking into account guest idle time. 4441ERST 4442 4443DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4444 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4445 " the guest without waiting for gdb to connect; use -S too\n" 4446 " if you want it to not start execution.)\n", 4447 QEMU_ARCH_ALL) 4448SRST 4449``-gdb dev`` 4450 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4451 in the System Emulation Users Guide). Note that this option does not pause QEMU 4452 execution -- if you want QEMU to not start the guest until you 4453 connect with gdb and issue a ``continue`` command, you will need to 4454 also pass the ``-S`` option to QEMU. 4455 4456 The most usual configuration is to listen on a local TCP socket:: 4457 4458 -gdb tcp::3117 4459 4460 but you can specify other backends; UDP, pseudo TTY, or even stdio 4461 are all reasonable use cases. For example, a stdio connection 4462 allows you to start QEMU from within gdb and establish the 4463 connection via a pipe: 4464 4465 .. parsed-literal:: 4466 4467 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4468ERST 4469 4470DEF("s", 0, QEMU_OPTION_s, \ 4471 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4472 QEMU_ARCH_ALL) 4473SRST 4474``-s`` 4475 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4476 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4477ERST 4478 4479DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4480 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4481 QEMU_ARCH_ALL) 4482SRST 4483``-d item1[,...]`` 4484 Enable logging of specified items. Use '-d help' for a list of log 4485 items. 4486ERST 4487 4488DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4489 "-D logfile output log to logfile (default stderr)\n", 4490 QEMU_ARCH_ALL) 4491SRST 4492``-D logfile`` 4493 Output log in logfile instead of to stderr 4494ERST 4495 4496DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4497 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4498 QEMU_ARCH_ALL) 4499SRST 4500``-dfilter range1[,...]`` 4501 Filter debug output to that relevant to a range of target addresses. 4502 The filter spec can be either start+size, start-size or start..end 4503 where start end and size are the addresses and sizes required. For 4504 example: 4505 4506 :: 4507 4508 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4509 4510 Will dump output for any code in the 0x1000 sized block starting at 4511 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4512 another 0x1000 sized block starting at 0xffffffc00005f000. 4513ERST 4514 4515DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4516 "-seed number seed the pseudo-random number generator\n", 4517 QEMU_ARCH_ALL) 4518SRST 4519``-seed number`` 4520 Force the guest to use a deterministic pseudo-random number 4521 generator, seeded with number. This does not affect crypto routines 4522 within the host. 4523ERST 4524 4525DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4526 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4527 QEMU_ARCH_ALL) 4528SRST 4529``-L path`` 4530 Set the directory for the BIOS, VGA BIOS and keymaps. 4531 4532 To list all the data directories, use ``-L help``. 4533ERST 4534 4535DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4536 "-enable-kvm enable KVM full virtualization support\n", 4537 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4538 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4539SRST 4540``-enable-kvm`` 4541 Enable KVM full virtualization support. This option is only 4542 available if KVM support is enabled when compiling. 4543ERST 4544 4545DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4546 "-xen-domid id specify xen guest domain id\n", 4547 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4548DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4549 "-xen-attach attach to existing xen domain\n" 4550 " libxl will use this when starting QEMU\n", 4551 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4552DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4553 "-xen-domid-restrict restrict set of available xen operations\n" 4554 " to specified domain id. (Does not affect\n" 4555 " xenpv machine type).\n", 4556 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4557SRST 4558``-xen-domid id`` 4559 Specify xen guest domain id (XEN only). 4560 4561``-xen-attach`` 4562 Attach to existing xen domain. libxl will use this when starting 4563 QEMU (XEN only). Restrict set of available xen operations to 4564 specified domain id (XEN only). 4565ERST 4566 4567DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4568 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4569SRST 4570``-no-reboot`` 4571 Exit instead of rebooting. 4572ERST 4573 4574DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4575 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4576SRST 4577``-no-shutdown`` 4578 Don't exit QEMU on guest shutdown, but instead only stop the 4579 emulation. This allows for instance switching to monitor to commit 4580 changes to the disk image. 4581ERST 4582 4583DEF("action", HAS_ARG, QEMU_OPTION_action, 4584 "-action reboot=reset|shutdown\n" 4585 " action when guest reboots [default=reset]\n" 4586 "-action shutdown=poweroff|pause\n" 4587 " action when guest shuts down [default=poweroff]\n" 4588 "-action panic=pause|shutdown|exit-failure|none\n" 4589 " action when guest panics [default=shutdown]\n" 4590 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4591 " action when watchdog fires [default=reset]\n", 4592 QEMU_ARCH_ALL) 4593SRST 4594``-action event=action`` 4595 The action parameter serves to modify QEMU's default behavior when 4596 certain guest events occur. It provides a generic method for specifying the 4597 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4598 parameters. 4599 4600 Examples: 4601 4602 ``-action panic=none`` 4603 ``-action reboot=shutdown,shutdown=pause`` 4604 ``-device i6300esb -action watchdog=pause`` 4605 4606ERST 4607 4608DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4609 "-loadvm [tag|id]\n" \ 4610 " start right away with a saved state (loadvm in monitor)\n", 4611 QEMU_ARCH_ALL) 4612SRST 4613``-loadvm file`` 4614 Start right away with a saved state (``loadvm`` in monitor) 4615ERST 4616 4617#ifndef _WIN32 4618DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4619 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4620#endif 4621SRST 4622``-daemonize`` 4623 Daemonize the QEMU process after initialization. QEMU will not 4624 detach from standard IO until it is ready to receive connections on 4625 any of its devices. This option is a useful way for external 4626 programs to launch QEMU without having to cope with initialization 4627 race conditions. 4628ERST 4629 4630DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4631 "-option-rom rom load a file, rom, into the option ROM space\n", 4632 QEMU_ARCH_ALL) 4633SRST 4634``-option-rom file`` 4635 Load the contents of file as an option ROM. This option is useful to 4636 load things like EtherBoot. 4637ERST 4638 4639DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4640 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4641 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4642 QEMU_ARCH_ALL) 4643 4644SRST 4645``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4646 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4647 the current UTC or local time, respectively. ``localtime`` is 4648 required for correct date in MS-DOS or Windows. To start at a 4649 specific point in time, provide datetime in the format 4650 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4651 4652 By default the RTC is driven by the host system time. This allows 4653 using of the RTC as accurate reference clock inside the guest, 4654 specifically if the host time is smoothly following an accurate 4655 external reference clock, e.g. via NTP. If you want to isolate the 4656 guest time from the host, you can set ``clock`` to ``rt`` instead, 4657 which provides a host monotonic clock if host support it. To even 4658 prevent the RTC from progressing during suspension, you can set 4659 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4660 recommended especially in icount mode in order to preserve 4661 determinism; however, note that in icount mode the speed of the 4662 virtual clock is variable and can in general differ from the host 4663 clock. 4664 4665 Enable ``driftfix`` (i386 targets only) if you experience time drift 4666 problems, specifically with Windows' ACPI HAL. This option will try 4667 to figure out how many timer interrupts were not processed by the 4668 Windows guest and will re-inject them. 4669ERST 4670 4671DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4672 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4673 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4674 " instruction, enable aligning the host and virtual clocks\n" \ 4675 " or disable real time cpu sleeping, and optionally enable\n" \ 4676 " record-and-replay mode\n", QEMU_ARCH_ALL) 4677SRST 4678``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4679 Enable virtual instruction counter. The virtual cpu will execute one 4680 instruction every 2^N ns of virtual time. If ``auto`` is specified 4681 then the virtual cpu speed will be automatically adjusted to keep 4682 virtual time within a few seconds of real time. 4683 4684 Note that while this option can give deterministic behavior, it does 4685 not provide cycle accurate emulation. Modern CPUs contain 4686 superscalar out of order cores with complex cache hierarchies. The 4687 number of instructions executed often has little or no correlation 4688 with actual performance. 4689 4690 When the virtual cpu is sleeping, the virtual time will advance at 4691 default speed unless ``sleep=on`` is specified. With 4692 ``sleep=on``, the virtual time will jump to the next timer 4693 deadline instantly whenever the virtual cpu goes to sleep mode and 4694 will not advance if no timer is enabled. This behavior gives 4695 deterministic execution times from the guest point of view. 4696 The default if icount is enabled is ``sleep=off``. 4697 ``sleep=on`` cannot be used together with either ``shift=auto`` 4698 or ``align=on``. 4699 4700 ``align=on`` will activate the delay algorithm which will try to 4701 synchronise the host clock and the virtual clock. The goal is to 4702 have a guest running at the real frequency imposed by the shift 4703 option. Whenever the guest clock is behind the host clock and if 4704 ``align=on`` is specified then we print a message to the user to 4705 inform about the delay. Currently this option does not work when 4706 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4707 shift values for which the guest clock runs ahead of the host clock. 4708 Typically this happens when the shift value is high (how high 4709 depends on the host machine). The default if icount is enabled 4710 is ``align=off``. 4711 4712 When the ``rr`` option is specified deterministic record/replay is 4713 enabled. The ``rrfile=`` option must also be provided to 4714 specify the path to the replay log. In record mode data is written 4715 to this file, and in replay mode it is read back. 4716 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4717 name. In record mode, a new VM snapshot with the given name is created 4718 at the start of execution recording. In replay mode this option 4719 specifies the snapshot name used to load the initial VM state. 4720ERST 4721 4722DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4723 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4724 " action when watchdog fires [default=reset]\n", 4725 QEMU_ARCH_ALL) 4726SRST 4727``-watchdog-action action`` 4728 The action controls what QEMU will do when the watchdog timer 4729 expires. The default is ``reset`` (forcefully reset the guest). 4730 Other possible actions are: ``shutdown`` (attempt to gracefully 4731 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4732 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4733 guest), ``debug`` (print a debug message and continue), or ``none`` 4734 (do nothing). 4735 4736 Note that the ``shutdown`` action requires that the guest responds 4737 to ACPI signals, which it may not be able to do in the sort of 4738 situations where the watchdog would have expired, and thus 4739 ``-watchdog-action shutdown`` is not recommended for production use. 4740 4741 Examples: 4742 4743 ``-device i6300esb -watchdog-action pause`` 4744 4745ERST 4746 4747DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4748 "-echr chr set terminal escape character instead of ctrl-a\n", 4749 QEMU_ARCH_ALL) 4750SRST 4751``-echr numeric_ascii_value`` 4752 Change the escape character used for switching to the monitor when 4753 using monitor and serial sharing. The default is ``0x01`` when using 4754 the ``-nographic`` option. ``0x01`` is equal to pressing 4755 ``Control-a``. You can select a different character from the ascii 4756 control keys where 1 through 26 map to Control-a through Control-z. 4757 For instance you could use the either of the following to change the 4758 escape character to Control-t. 4759 4760 ``-echr 0x14``; \ ``-echr 20`` 4761 4762ERST 4763 4764DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4765 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4766 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4767 "-incoming unix:socketpath\n" \ 4768 " prepare for incoming migration, listen on\n" \ 4769 " specified protocol and socket address\n" \ 4770 "-incoming fd:fd\n" \ 4771 "-incoming file:filename[,offset=offset]\n" \ 4772 "-incoming exec:cmdline\n" \ 4773 " accept incoming migration on given file descriptor\n" \ 4774 " or from given external command\n" \ 4775 "-incoming defer\n" \ 4776 " wait for the URI to be specified via migrate_incoming\n", 4777 QEMU_ARCH_ALL) 4778SRST 4779``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4780 \ 4781``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4782 Prepare for incoming migration, listen on a given tcp port. 4783 4784``-incoming unix:socketpath`` 4785 Prepare for incoming migration, listen on a given unix socket. 4786 4787``-incoming fd:fd`` 4788 Accept incoming migration from a given file descriptor. 4789 4790``-incoming file:filename[,offset=offset]`` 4791 Accept incoming migration from a given file starting at offset. 4792 offset allows the common size suffixes, or a 0x prefix, but not both. 4793 4794``-incoming exec:cmdline`` 4795 Accept incoming migration as an output from specified external 4796 command. 4797 4798``-incoming defer`` 4799 Wait for the URI to be specified via migrate\_incoming. The monitor 4800 can be used to change settings (such as migration parameters) prior 4801 to issuing the migrate\_incoming to allow the migration to begin. 4802ERST 4803 4804DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4805 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4806SRST 4807``-only-migratable`` 4808 Only allow migratable devices. Devices will not be allowed to enter 4809 an unmigratable state. 4810ERST 4811 4812DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4813 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4814SRST 4815``-nodefaults`` 4816 Don't create default devices. Normally, QEMU sets the default 4817 devices like serial port, parallel port, virtual console, monitor 4818 device, VGA adapter, floppy and CD-ROM drive and others. The 4819 ``-nodefaults`` option will disable all those default devices. 4820ERST 4821 4822#ifndef _WIN32 4823DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4824 "-runas user change to user id user just before starting the VM\n" \ 4825 " user can be numeric uid:gid instead\n", 4826 QEMU_ARCH_ALL) 4827#endif 4828SRST 4829``-runas user`` 4830 Immediately before starting guest execution, drop root privileges, 4831 switching to the specified user. This option is deprecated, use 4832 ``-run-with user=...`` instead. 4833ERST 4834 4835DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4836 "-prom-env variable=value\n" 4837 " set OpenBIOS nvram variables\n", 4838 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4839SRST 4840``-prom-env variable=value`` 4841 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4842 4843 :: 4844 4845 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4846 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4847 4848 :: 4849 4850 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4851 -prom-env 'boot-device=hd:2,\yaboot' \ 4852 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4853ERST 4854DEF("semihosting", 0, QEMU_OPTION_semihosting, 4855 "-semihosting semihosting mode\n", 4856 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4857 QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 4858SRST 4859``-semihosting`` 4860 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, RISC-V only). 4861 4862 .. warning:: 4863 Note that this allows guest direct access to the host filesystem, so 4864 should only be used with a trusted guest OS. 4865 4866 See the -semihosting-config option documentation for further 4867 information about the facilities this enables. 4868ERST 4869DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4870 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4871 " semihosting configuration\n", 4872QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4873QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 4874SRST 4875``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4876 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, RISC-V 4877 only). 4878 4879 .. warning:: 4880 Note that this allows guest direct access to the host filesystem, so 4881 should only be used with a trusted guest OS. 4882 4883 ``target=native|gdb|auto`` 4884 Defines where the semihosting calls will be addressed, to QEMU 4885 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4886 means ``gdb`` during debug sessions and ``native`` otherwise. 4887 4888 ``chardev=str1`` 4889 Send the output to a chardev backend output for native or auto 4890 output when not in gdb 4891 4892 ``userspace=on|off`` 4893 Allows code running in guest userspace to access the semihosting 4894 interface. The default is that only privileged guest code can 4895 make semihosting calls. Note that setting ``userspace=on`` should 4896 only be used if all guest code is trusted (for example, in 4897 bare-metal test case code). 4898 4899 ``arg=str1,arg=str2,...`` 4900 Allows the user to pass input arguments, and can be used 4901 multiple times to build up a list. The old-style 4902 ``-kernel``/``-append`` method of passing a command line is 4903 still supported for backward compatibility. If both the 4904 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4905 specified, the former is passed to semihosting as it always 4906 takes precedence. 4907ERST 4908DEF("old-param", 0, QEMU_OPTION_old_param, 4909 "-old-param old param mode\n", QEMU_ARCH_ARM) 4910SRST 4911``-old-param`` 4912 Old param mode (ARM only). 4913ERST 4914 4915DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4916 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4917 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4918 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4919 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4920 " by the kernel, but typically no longer used by modern\n" \ 4921 " C library implementations.\n" \ 4922 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4923 " to elevate privileges using set*uid|gid system calls.\n" \ 4924 " The value 'children' will deny set*uid|gid system calls for\n" \ 4925 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4926 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4927 " blocking *fork and execve\n" \ 4928 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4929 QEMU_ARCH_ALL) 4930SRST 4931``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4932 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4933 filtering and 'off' will disable it. The default is 'off'. 4934 4935 ``obsolete=string`` 4936 Enable Obsolete system calls 4937 4938 ``elevateprivileges=string`` 4939 Disable set\*uid\|gid system calls 4940 4941 ``spawn=string`` 4942 Disable \*fork and execve 4943 4944 ``resourcecontrol=string`` 4945 Disable process affinity and schedular priority 4946ERST 4947 4948DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4949 "-readconfig <file>\n" 4950 " read config file\n", QEMU_ARCH_ALL) 4951SRST 4952``-readconfig file`` 4953 Read device configuration from file. This approach is useful when 4954 you want to spawn QEMU process with many command line options but 4955 you don't want to exceed the command line character limit. 4956ERST 4957 4958DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4959 "-no-user-config\n" 4960 " do not load default user-provided config files at startup\n", 4961 QEMU_ARCH_ALL) 4962SRST 4963``-no-user-config`` 4964 The ``-no-user-config`` option makes QEMU not load any of the 4965 user-provided config files on sysconfdir. 4966ERST 4967 4968DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4969 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4970 " specify tracing options\n", 4971 QEMU_ARCH_ALL) 4972SRST 4973``-trace [[enable=]pattern][,events=file][,file=file]`` 4974 .. include:: ../qemu-option-trace.rst.inc 4975 4976ERST 4977DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4978 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4979 " load a plugin\n", 4980 QEMU_ARCH_ALL) 4981SRST 4982``-plugin file=file[,argname=argvalue]`` 4983 Load a plugin. 4984 4985 ``file=file`` 4986 Load the given plugin from a shared library file. 4987 4988 ``argname=argvalue`` 4989 Argument passed to the plugin. (Can be given multiple times.) 4990ERST 4991 4992HXCOMM Internal use 4993DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4994DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4995 4996#ifdef CONFIG_POSIX 4997DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4998 "-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]\n" 4999 " Set miscellaneous QEMU process lifecycle options:\n" 5000 " async-teardown=on enables asynchronous teardown (Linux only)\n" 5001 " chroot=dir chroot to dir just before starting the VM\n" 5002 " user=username switch to the specified user before starting the VM\n" 5003 " user=uid:gid ditto, but use specified user-ID and group-ID instead\n", 5004 QEMU_ARCH_ALL) 5005SRST 5006``-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]`` 5007 Set QEMU process lifecycle options. 5008 5009 ``async-teardown=on`` enables asynchronous teardown. A new process called 5010 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5011 space with the main QEMU process, using clone. It will wait for the 5012 main QEMU process to terminate completely, and then exit. This allows 5013 QEMU to terminate very quickly even if the guest was huge, leaving the 5014 teardown of the address space to the cleanup process. Since the cleanup 5015 process shares the same cgroups as the main QEMU process, accounting is 5016 performed correctly. This only works if the cleanup process is not 5017 forcefully killed with SIGKILL before the main QEMU process has 5018 terminated completely. 5019 5020 ``chroot=dir`` can be used for doing a chroot to the specified directory 5021 immediately before starting the guest execution. This is especially useful 5022 in combination with -runas. 5023 5024 ``user=username`` or ``user=uid:gid`` can be used to drop root privileges 5025 by switching to the specified user (via username) or user and group 5026 (via uid:gid) immediately before starting guest execution. 5027ERST 5028#endif 5029 5030DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5031 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5032 " control error message format\n" 5033 " timestamp=on enables timestamps (default: off)\n" 5034 " guest-name=on enables guest name prefix but only if\n" 5035 " -name guest option is set (default: off)\n", 5036 QEMU_ARCH_ALL) 5037SRST 5038``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5039 Control error message format. 5040 5041 ``timestamp=on|off`` 5042 Prefix messages with a timestamp. Default is off. 5043 5044 ``guest-name=on|off`` 5045 Prefix messages with guest name but only if -name guest option is set 5046 otherwise the option is ignored. Default is off. 5047ERST 5048 5049DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5050 "-dump-vmstate <file>\n" 5051 " Output vmstate information in JSON format to file.\n" 5052 " Use the scripts/vmstate-static-checker.py file to\n" 5053 " check for possible regressions in migration code\n" 5054 " by comparing two such vmstate dumps.\n", 5055 QEMU_ARCH_ALL) 5056SRST 5057``-dump-vmstate file`` 5058 Dump json-encoded vmstate information for current machine type to 5059 file in file 5060ERST 5061 5062DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5063 "-enable-sync-profile\n" 5064 " enable synchronization profiling\n", 5065 QEMU_ARCH_ALL) 5066SRST 5067``-enable-sync-profile`` 5068 Enable synchronization profiling. 5069ERST 5070 5071#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5072DEF("perfmap", 0, QEMU_OPTION_perfmap, 5073 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5074 QEMU_ARCH_ALL) 5075SRST 5076``-perfmap`` 5077 Generate a map file for Linux perf tools that will allow basic profiling 5078 information to be broken down into basic blocks. 5079ERST 5080 5081DEF("jitdump", 0, QEMU_OPTION_jitdump, 5082 "-jitdump generate a jit-${pid}.dump file for perf\n", 5083 QEMU_ARCH_ALL) 5084SRST 5085``-jitdump`` 5086 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5087 names, line numbers and JITted code. 5088ERST 5089#endif 5090 5091DEFHEADING() 5092 5093DEFHEADING(Generic object creation:) 5094 5095DEF("object", HAS_ARG, QEMU_OPTION_object, 5096 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5097 " create a new object of type TYPENAME setting properties\n" 5098 " in the order they are specified. Note that the 'id'\n" 5099 " property must be set. These objects are placed in the\n" 5100 " '/objects' path.\n", 5101 QEMU_ARCH_ALL) 5102SRST 5103``-object typename[,prop1=value1,...]`` 5104 Create a new object of type typename setting properties in the order 5105 they are specified. Note that the 'id' property must be set. These 5106 objects are placed in the '/objects' path. 5107 5108 ``-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,offset=offset,readonly=on|off,rom=on|off|auto`` 5109 Creates a memory file backend object, which can be used to back 5110 the guest RAM with huge pages. 5111 5112 The ``id`` parameter is a unique ID that will be used to 5113 reference this memory region in other parameters, e.g. ``-numa``, 5114 ``-device nvdimm``, etc. 5115 5116 The ``size`` option provides the size of the memory region, and 5117 accepts common suffixes, e.g. ``500M``. 5118 5119 The ``mem-path`` provides the path to either a shared memory or 5120 huge page filesystem mount. 5121 5122 The ``share`` boolean option determines whether the memory 5123 region is marked as private to QEMU, or shared. The latter 5124 allows a co-operating external process to access the QEMU memory 5125 region. 5126 5127 Setting share=on might affect the ability to configure NUMA 5128 bindings for the memory backend under some circumstances, see 5129 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5130 source tree for additional details. 5131 5132 Setting the ``discard-data`` boolean option to on indicates that 5133 file contents can be destroyed when QEMU exits, to avoid 5134 unnecessarily flushing data to the backing file. Note that 5135 ``discard-data`` is only an optimization, and QEMU might not 5136 discard file contents if it aborts unexpectedly or is terminated 5137 using SIGKILL. 5138 5139 The ``merge`` boolean option enables memory merge, also known as 5140 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5141 the pages for memory deduplication. 5142 5143 Setting the ``dump`` boolean option to off excludes the memory 5144 from core dumps. This feature is also known as MADV\_DONTDUMP. 5145 5146 The ``prealloc`` boolean option enables memory preallocation. 5147 5148 The ``host-nodes`` option binds the memory range to a list of 5149 NUMA host nodes. 5150 5151 The ``policy`` option sets the NUMA policy to one of the 5152 following values: 5153 5154 ``default`` 5155 default host policy 5156 5157 ``preferred`` 5158 prefer the given host node list for allocation 5159 5160 ``bind`` 5161 restrict memory allocation to the given host node list 5162 5163 ``interleave`` 5164 interleave memory allocations across the given host node 5165 list 5166 5167 The ``align`` option specifies the base address alignment when 5168 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5169 ``2M``. Some backend store specified by ``mem-path`` requires an 5170 alignment different than the default one used by QEMU, eg the 5171 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5172 such cases, users can specify the required alignment via this 5173 option. 5174 5175 The ``offset`` option specifies the offset into the target file 5176 that the region starts at. You can use this parameter to back 5177 multiple regions with a single file. 5178 5179 The ``pmem`` option specifies whether the backing file specified 5180 by ``mem-path`` is in host persistent memory that can be 5181 accessed using the SNIA NVM programming model (e.g. Intel 5182 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5183 operations to guarantee the persistence of its own writes to 5184 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5185 migration). Also, we will map the backend-file with MAP\_SYNC 5186 flag, which ensures the file metadata is in sync for 5187 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5188 requires support from both the host kernel (since Linux kernel 5189 4.15) and the filesystem of ``mem-path`` mounted with DAX 5190 option. 5191 5192 The ``readonly`` option specifies whether the backing file is opened 5193 read-only or read-write (default). 5194 5195 The ``rom`` option specifies whether to create Read Only Memory 5196 (ROM) that cannot be modified by the VM. Any write attempts to such 5197 ROM will be denied. Most use cases want proper RAM instead of ROM. 5198 However, selected use cases, like R/O NVDIMMs, can benefit from 5199 ROM. If set to ``on``, create ROM; if set to ``off``, create 5200 writable RAM; if set to ``auto`` (default), the value of the 5201 ``readonly`` option is used. This option is primarily helpful when 5202 we want to have writable RAM in configurations that would 5203 traditionally create ROM before the ``rom`` option was introduced: 5204 VM templating, where we want to open a file readonly 5205 (``readonly=on``) and mark the memory to be private for QEMU 5206 (``share=off``). For this use case, we need writable RAM instead 5207 of ROM, and want to also set ``rom=off``. 5208 5209 ``-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`` 5210 Creates a memory backend object, which can be used to back the 5211 guest RAM. Memory backend objects offer more control than the 5212 ``-m`` option that is traditionally used to define guest RAM. 5213 Please refer to ``memory-backend-file`` for a description of the 5214 options. 5215 5216 ``-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`` 5217 Creates an anonymous memory file backend object, which allows 5218 QEMU to share the memory with an external process (e.g. when 5219 using vhost-user). The memory is allocated with memfd and 5220 optional sealing. (Linux only) 5221 5222 The ``seal`` option creates a sealed-file, that will block 5223 further resizing the memory ('on' by default). 5224 5225 The ``hugetlb`` option specify the file to be created resides in 5226 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5227 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5228 the hugetlb page size on systems that support multiple hugetlb 5229 page sizes (it must be a power of 2 value supported by the 5230 system). 5231 5232 In some versions of Linux, the ``hugetlb`` option is 5233 incompatible with the ``seal`` option (requires at least Linux 5234 4.16). 5235 5236 Please refer to ``memory-backend-file`` for a description of the 5237 other options. 5238 5239 The ``share`` boolean option is on by default with memfd. 5240 5241 ``-object iommufd,id=id[,fd=fd]`` 5242 Creates an iommufd backend which allows control of DMA mapping 5243 through the ``/dev/iommu`` device. 5244 5245 The ``id`` parameter is a unique ID which frontends (such as 5246 vfio-pci of vdpa) will use to connect with the iommufd backend. 5247 5248 The ``fd`` parameter is an optional pre-opened file descriptor 5249 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5250 across all subsystems, bringing the benefit of centralized 5251 reference counting. 5252 5253 ``-object rng-builtin,id=id`` 5254 Creates a random number generator backend which obtains entropy 5255 from QEMU builtin functions. The ``id`` parameter is a unique ID 5256 that will be used to reference this entropy backend from the 5257 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5258 uses this RNG backend. 5259 5260 ``-object rng-random,id=id,filename=/dev/random`` 5261 Creates a random number generator backend which obtains entropy 5262 from a device on the host. The ``id`` parameter is a unique ID 5263 that will be used to reference this entropy backend from the 5264 ``virtio-rng`` device. The ``filename`` parameter specifies 5265 which file to obtain entropy from and if omitted defaults to 5266 ``/dev/urandom``. 5267 5268 ``-object rng-egd,id=id,chardev=chardevid`` 5269 Creates a random number generator backend which obtains entropy 5270 from an external daemon running on the host. The ``id`` 5271 parameter is a unique ID that will be used to reference this 5272 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5273 parameter is the unique ID of a character device backend that 5274 provides the connection to the RNG daemon. 5275 5276 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5277 Creates a TLS anonymous credentials object, which can be used to 5278 provide TLS support on network backends. The ``id`` parameter is 5279 a unique ID which network backends will use to access the 5280 credentials. The ``endpoint`` is either ``server`` or ``client`` 5281 depending on whether the QEMU network backend that uses the 5282 credentials will be acting as a client or as a server. If 5283 ``verify-peer`` is enabled (the default) then once the handshake 5284 is completed, the peer credentials will be verified, though this 5285 is a no-op for anonymous credentials. 5286 5287 The dir parameter tells QEMU where to find the credential files. 5288 For server endpoints, this directory may contain a file 5289 dh-params.pem providing diffie-hellman parameters to use for the 5290 TLS server. If the file is missing, QEMU will generate a set of 5291 DH parameters at startup. This is a computationally expensive 5292 operation that consumes random pool entropy, so it is 5293 recommended that a persistent set of parameters be generated 5294 upfront and saved. 5295 5296 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5297 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5298 can be used to provide TLS support on network backends. The 5299 ``id`` parameter is a unique ID which network backends will use 5300 to access the credentials. The ``endpoint`` is either ``server`` 5301 or ``client`` depending on whether the QEMU network backend that 5302 uses the credentials will be acting as a client or as a server. 5303 For clients only, ``username`` is the username which will be 5304 sent to the server. If omitted it defaults to "qemu". 5305 5306 The dir parameter tells QEMU where to find the keys file. It is 5307 called "dir/keys.psk" and contains "username:key" pairs. This 5308 file can most easily be created using the GnuTLS ``psktool`` 5309 program. 5310 5311 For server endpoints, dir may also contain a file dh-params.pem 5312 providing diffie-hellman parameters to use for the TLS server. 5313 If the file is missing, QEMU will generate a set of DH 5314 parameters at startup. This is a computationally expensive 5315 operation that consumes random pool entropy, so it is 5316 recommended that a persistent set of parameters be generated up 5317 front and saved. 5318 5319 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5320 Creates a TLS anonymous credentials object, which can be used to 5321 provide TLS support on network backends. The ``id`` parameter is 5322 a unique ID which network backends will use to access the 5323 credentials. The ``endpoint`` is either ``server`` or ``client`` 5324 depending on whether the QEMU network backend that uses the 5325 credentials will be acting as a client or as a server. If 5326 ``verify-peer`` is enabled (the default) then once the handshake 5327 is completed, the peer credentials will be verified. With x509 5328 certificates, this implies that the clients must be provided 5329 with valid client certificates too. 5330 5331 The dir parameter tells QEMU where to find the credential files. 5332 For server endpoints, this directory may contain a file 5333 dh-params.pem providing diffie-hellman parameters to use for the 5334 TLS server. If the file is missing, QEMU will generate a set of 5335 DH parameters at startup. This is a computationally expensive 5336 operation that consumes random pool entropy, so it is 5337 recommended that a persistent set of parameters be generated 5338 upfront and saved. 5339 5340 For x509 certificate credentials the directory will contain 5341 further files providing the x509 certificates. The certificates 5342 must be stored in PEM format, in filenames ca-cert.pem, 5343 ca-crl.pem (optional), server-cert.pem (only servers), 5344 server-key.pem (only servers), client-cert.pem (only clients), 5345 and client-key.pem (only clients). 5346 5347 For the server-key.pem and client-key.pem files which contain 5348 sensitive private keys, it is possible to use an encrypted 5349 version by providing the passwordid parameter. This provides the 5350 ID of a previously created ``secret`` object containing the 5351 password for decryption. 5352 5353 The priority parameter allows to override the global default 5354 priority used by gnutls. This can be useful if the system 5355 administrator needs to use a weaker set of crypto priorities for 5356 QEMU without potentially forcing the weakness onto all 5357 applications. Or conversely if one wants wants a stronger 5358 default for QEMU than for all other applications, they can do 5359 this through this parameter. Its format is a gnutls priority 5360 string as described at 5361 https://gnutls.org/manual/html_node/Priority-Strings.html. 5362 5363 ``-object tls-cipher-suites,id=id,priority=priority`` 5364 Creates a TLS cipher suites object, which can be used to control 5365 the TLS cipher/protocol algorithms that applications are permitted 5366 to use. 5367 5368 The ``id`` parameter is a unique ID which frontends will use to 5369 access the ordered list of permitted TLS cipher suites from the 5370 host. 5371 5372 The ``priority`` parameter allows to override the global default 5373 priority used by gnutls. This can be useful if the system 5374 administrator needs to use a weaker set of crypto priorities for 5375 QEMU without potentially forcing the weakness onto all 5376 applications. Or conversely if one wants wants a stronger 5377 default for QEMU than for all other applications, they can do 5378 this through this parameter. Its format is a gnutls priority 5379 string as described at 5380 https://gnutls.org/manual/html_node/Priority-Strings.html. 5381 5382 An example of use of this object is to control UEFI HTTPS Boot. 5383 The tls-cipher-suites object exposes the ordered list of permitted 5384 TLS cipher suites from the host side to the guest firmware, via 5385 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5386 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5387 guest-side TLS. 5388 5389 In the following example, the priority at which the host-side policy 5390 is retrieved is given by the ``priority`` property. 5391 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5392 refer to /etc/crypto-policies/back-ends/gnutls.config. 5393 5394 .. parsed-literal:: 5395 5396 # |qemu_system| \\ 5397 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5398 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5399 5400 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5401 Interval t can't be 0, this filter batches the packet delivery: 5402 all packets arriving in a given interval on netdev netdevid are 5403 delayed until the end of the interval. Interval is in 5404 microseconds. ``status`` is optional that indicate whether the 5405 netfilter is on (enabled) or off (disabled), the default status 5406 for netfilter will be 'on'. 5407 5408 queue all\|rx\|tx is an option that can be applied to any 5409 netfilter. 5410 5411 ``all``: the filter is attached both to the receive and the 5412 transmit queue of the netdev (default). 5413 5414 ``rx``: the filter is attached to the receive queue of the 5415 netdev, where it will receive packets sent to the netdev. 5416 5417 ``tx``: the filter is attached to the transmit queue of the 5418 netdev, where it will receive packets sent by the netdev. 5419 5420 position head\|tail\|id=<id> is an option to specify where the 5421 filter should be inserted in the filter list. It can be applied 5422 to any netfilter. 5423 5424 ``head``: the filter is inserted at the head of the filter list, 5425 before any existing filters. 5426 5427 ``tail``: the filter is inserted at the tail of the filter list, 5428 behind any existing filters (default). 5429 5430 ``id=<id>``: the filter is inserted before or behind the filter 5431 specified by <id>, see the insert option below. 5432 5433 insert behind\|before is an option to specify where to insert 5434 the new filter relative to the one specified with 5435 position=id=<id>. It can be applied to any netfilter. 5436 5437 ``before``: insert before the specified filter. 5438 5439 ``behind``: insert behind the specified filter (default). 5440 5441 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5442 filter-mirror on netdev netdevid,mirror net packet to 5443 chardevchardevid, if it has the vnet\_hdr\_support flag, 5444 filter-mirror will mirror packet with vnet\_hdr\_len. 5445 5446 ``-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]`` 5447 filter-redirector on netdev netdevid,redirect filter's net 5448 packet to chardev chardevid,and redirect indev's packet to 5449 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5450 will redirect packet with vnet\_hdr\_len. Create a 5451 filter-redirector we need to differ outdev id from indev id, id 5452 can not be the same. we can just use indev or outdev, but at 5453 least one of indev or outdev need to be specified. 5454 5455 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5456 Filter-rewriter is a part of COLO project.It will rewrite tcp 5457 packet to secondary from primary to keep secondary tcp 5458 connection,and rewrite tcp packet to primary from secondary make 5459 tcp packet can be handled by client.if it has the 5460 vnet\_hdr\_support flag, we can parse packet with vnet header. 5461 5462 usage: colo secondary: -object 5463 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5464 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5465 filter-rewriter,id=rew0,netdev=hn0,queue=all 5466 5467 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5468 Dump the network traffic on netdev dev to the file specified by 5469 filename. At most len bytes (64k by default) per packet are 5470 stored. The file format is libpcap, so it can be analyzed with 5471 tools such as tcpdump or Wireshark. 5472 5473 ``-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}]`` 5474 Colo-compare gets packet from primary\_in chardevid and 5475 secondary\_in, then compare whether the payload of primary packet 5476 and secondary packet are the same. If same, it will output 5477 primary packet to out\_dev, else it will notify COLO-framework to do 5478 checkpoint and send primary packet to out\_dev. In order to 5479 improve efficiency, we need to put the task of comparison in 5480 another iothread. If it has the vnet\_hdr\_support flag, 5481 colo compare will send/recv packet with vnet\_hdr\_len. 5482 The compare\_timeout=@var{ms} determines the maximum time of the 5483 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5484 is to set the period of scanning expired primary node network packets. 5485 The max\_queue\_size=@var{size} is to set the max compare queue 5486 size depend on user environment. 5487 If user want to use Xen COLO, need to add the notify\_dev to 5488 notify Xen colo-frame to do checkpoint. 5489 5490 COLO-compare must be used with the help of filter-mirror, 5491 filter-redirector and filter-rewriter. 5492 5493 :: 5494 5495 KVM COLO 5496 5497 primary: 5498 -netdev tap,id=hn0,vhost=off 5499 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5500 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5501 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5502 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5503 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5504 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5505 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5506 -object iothread,id=iothread1 5507 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5508 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5509 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5510 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5511 5512 secondary: 5513 -netdev tap,id=hn0,vhost=off 5514 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5515 -chardev socket,id=red0,host=3.3.3.3,port=9003 5516 -chardev socket,id=red1,host=3.3.3.3,port=9004 5517 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5518 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5519 5520 5521 Xen COLO 5522 5523 primary: 5524 -netdev tap,id=hn0,vhost=off 5525 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5526 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5527 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5528 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5529 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5530 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5531 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5532 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5533 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5534 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5535 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5536 -object iothread,id=iothread1 5537 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5538 5539 secondary: 5540 -netdev tap,id=hn0,vhost=off 5541 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5542 -chardev socket,id=red0,host=3.3.3.3,port=9003 5543 -chardev socket,id=red1,host=3.3.3.3,port=9004 5544 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5545 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5546 5547 If you want to know the detail of above command line, you can 5548 read the colo-compare git log. 5549 5550 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5551 Creates a cryptodev backend which executes crypto operations from 5552 the QEMU cipher APIs. The id parameter is a unique ID that will 5553 be used to reference this cryptodev backend from the 5554 ``virtio-crypto`` device. The queues parameter is optional, 5555 which specify the queue number of cryptodev backend, the default 5556 of queues is 1. 5557 5558 .. parsed-literal:: 5559 5560 # |qemu_system| \\ 5561 [...] \\ 5562 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5563 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5564 [...] 5565 5566 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5567 Creates a vhost-user cryptodev backend, backed by a chardev 5568 chardevid. The id parameter is a unique ID that will be used to 5569 reference this cryptodev backend from the ``virtio-crypto`` 5570 device. The chardev should be a unix domain socket backed one. 5571 The vhost-user uses a specifically defined protocol to pass 5572 vhost ioctl replacement messages to an application on the other 5573 end of the socket. The queues parameter is optional, which 5574 specify the queue number of cryptodev backend for multiqueue 5575 vhost-user, the default of queues is 1. 5576 5577 .. parsed-literal:: 5578 5579 # |qemu_system| \\ 5580 [...] \\ 5581 -chardev socket,id=chardev0,path=/path/to/socket \\ 5582 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5583 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5584 [...] 5585 5586 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5587 \ 5588 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5589 Defines a secret to store a password, encryption key, or some 5590 other sensitive data. The sensitive data can either be passed 5591 directly via the data parameter, or indirectly via the file 5592 parameter. Using the data parameter is insecure unless the 5593 sensitive data is encrypted. 5594 5595 The sensitive data can be provided in raw format (the default), 5596 or base64. When encoded as JSON, the raw format only supports 5597 valid UTF-8 characters, so base64 is recommended for sending 5598 binary data. QEMU will convert from which ever format is 5599 provided to the format it needs internally. eg, an RBD password 5600 can be provided in raw format, even though it will be base64 5601 encoded when passed onto the RBD sever. 5602 5603 For added protection, it is possible to encrypt the data 5604 associated with a secret using the AES-256-CBC cipher. Use of 5605 encryption is indicated by providing the keyid and iv 5606 parameters. The keyid parameter provides the ID of a previously 5607 defined secret that contains the AES-256 decryption key. This 5608 key should be 32-bytes long and be base64 encoded. The iv 5609 parameter provides the random initialization vector used for 5610 encryption of this particular secret and should be a base64 5611 encrypted string of the 16-byte IV. 5612 5613 The simplest (insecure) usage is to provide the secret inline 5614 5615 .. parsed-literal:: 5616 5617 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5618 5619 The simplest secure usage is to provide the secret via a file 5620 5621 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5622 secret,id=sec0,file=mypasswd.txt,format=raw 5623 5624 For greater security, AES-256-CBC should be used. To illustrate 5625 usage, consider the openssl command line tool which can encrypt 5626 the data. Note that when encrypting, the plaintext must be 5627 padded to the cipher block size (32 bytes) using the standard 5628 PKCS#5/6 compatible padding algorithm. 5629 5630 First a master key needs to be created in base64 encoding: 5631 5632 :: 5633 5634 # openssl rand -base64 32 > key.b64 5635 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5636 5637 Each secret to be encrypted needs to have a random 5638 initialization vector generated. These do not need to be kept 5639 secret 5640 5641 :: 5642 5643 # openssl rand -base64 16 > iv.b64 5644 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5645 5646 The secret to be defined can now be encrypted, in this case 5647 we're telling openssl to base64 encode the result, but it could 5648 be left as raw bytes if desired. 5649 5650 :: 5651 5652 # SECRET=$(printf "letmein" | 5653 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5654 5655 When launching QEMU, create a master secret pointing to 5656 ``key.b64`` and specify that to be used to decrypt the user 5657 password. Pass the contents of ``iv.b64`` to the second secret 5658 5659 .. parsed-literal:: 5660 5661 # |qemu_system| \\ 5662 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5663 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5664 data=$SECRET,iv=$(<iv.b64) 5665 5666 ``-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]`` 5667 Create a Secure Encrypted Virtualization (SEV) guest object, 5668 which can be used to provide the guest memory encryption support 5669 on AMD processors. 5670 5671 When memory encryption is enabled, one of the physical address 5672 bit (aka the C-bit) is utilized to mark if a memory page is 5673 protected. The ``cbitpos`` is used to provide the C-bit 5674 position. The C-bit position is Host family dependent hence user 5675 must provide this value. On EPYC, the value should be 47. 5676 5677 When memory encryption is enabled, we loose certain bits in 5678 physical address space. The ``reduced-phys-bits`` is used to 5679 provide the number of bits we loose in physical address space. 5680 Similar to C-bit, the value is Host family dependent. On EPYC, 5681 a guest will lose a maximum of 1 bit, so the value should be 1. 5682 5683 The ``sev-device`` provides the device file to use for 5684 communicating with the SEV firmware running inside AMD Secure 5685 Processor. The default device is '/dev/sev'. If hardware 5686 supports memory encryption then /dev/sev devices are created by 5687 CCP driver. 5688 5689 The ``policy`` provides the guest policy to be enforced by the 5690 SEV firmware and restrict what configuration and operational 5691 commands can be performed on this guest by the hypervisor. The 5692 policy should be provided by the guest owner and is bound to the 5693 guest and cannot be changed throughout the lifetime of the 5694 guest. The default is 0. 5695 5696 If guest ``policy`` allows sharing the key with another SEV 5697 guest then ``handle`` can be use to provide handle of the guest 5698 from which to share the key. 5699 5700 The ``dh-cert-file`` and ``session-file`` provides the guest 5701 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5702 and session parameters are used for establishing a cryptographic 5703 session with the guest owner to negotiate keys used for 5704 attestation. The file must be encoded in base64. 5705 5706 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5707 cmdline to a designated guest firmware page for measured Linux 5708 boot with -kernel. The default is off. (Since 6.2) 5709 5710 e.g to launch a SEV guest 5711 5712 .. parsed-literal:: 5713 5714 # |qemu_system_x86| \\ 5715 ...... \\ 5716 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5717 -machine ...,memory-encryption=sev0 \\ 5718 ..... 5719 5720 ``-object authz-simple,id=id,identity=string`` 5721 Create an authorization object that will control access to 5722 network services. 5723 5724 The ``identity`` parameter is identifies the user and its format 5725 depends on the network service that authorization object is 5726 associated with. For authorizing based on TLS x509 certificates, 5727 the identity must be the x509 distinguished name. Note that care 5728 must be taken to escape any commas in the distinguished name. 5729 5730 An example authorization object to validate a x509 distinguished 5731 name would look like: 5732 5733 .. parsed-literal:: 5734 5735 # |qemu_system| \\ 5736 ... \\ 5737 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5738 ... 5739 5740 Note the use of quotes due to the x509 distinguished name 5741 containing whitespace, and escaping of ','. 5742 5743 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5744 Create an authorization object that will control access to 5745 network services. 5746 5747 The ``filename`` parameter is the fully qualified path to a file 5748 containing the access control list rules in JSON format. 5749 5750 An example set of rules that match against SASL usernames might 5751 look like: 5752 5753 :: 5754 5755 { 5756 "rules": [ 5757 { "match": "fred", "policy": "allow", "format": "exact" }, 5758 { "match": "bob", "policy": "allow", "format": "exact" }, 5759 { "match": "danb", "policy": "deny", "format": "glob" }, 5760 { "match": "dan*", "policy": "allow", "format": "exact" }, 5761 ], 5762 "policy": "deny" 5763 } 5764 5765 When checking access the object will iterate over all the rules 5766 and the first rule to match will have its ``policy`` value 5767 returned as the result. If no rules match, then the default 5768 ``policy`` value is returned. 5769 5770 The rules can either be an exact string match, or they can use 5771 the simple UNIX glob pattern matching to allow wildcards to be 5772 used. 5773 5774 If ``refresh`` is set to true the file will be monitored and 5775 automatically reloaded whenever its content changes. 5776 5777 As with the ``authz-simple`` object, the format of the identity 5778 strings being matched depends on the network service, but is 5779 usually a TLS x509 distinguished name, or a SASL username. 5780 5781 An example authorization object to validate a SASL username 5782 would look like: 5783 5784 .. parsed-literal:: 5785 5786 # |qemu_system| \\ 5787 ... \\ 5788 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5789 ... 5790 5791 ``-object authz-pam,id=id,service=string`` 5792 Create an authorization object that will control access to 5793 network services. 5794 5795 The ``service`` parameter provides the name of a PAM service to 5796 use for authorization. It requires that a file 5797 ``/etc/pam.d/service`` exist to provide the configuration for 5798 the ``account`` subsystem. 5799 5800 An example authorization object to validate a TLS x509 5801 distinguished name would look like: 5802 5803 .. parsed-literal:: 5804 5805 # |qemu_system| \\ 5806 ... \\ 5807 -object authz-pam,id=auth0,service=qemu-vnc \\ 5808 ... 5809 5810 There would then be a corresponding config file for PAM at 5811 ``/etc/pam.d/qemu-vnc`` that contains: 5812 5813 :: 5814 5815 account requisite pam_listfile.so item=user sense=allow \ 5816 file=/etc/qemu/vnc.allow 5817 5818 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5819 of x509 distinguished names that are permitted access 5820 5821 :: 5822 5823 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5824 5825 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5826 Creates a dedicated event loop thread that devices can be 5827 assigned to. This is known as an IOThread. By default device 5828 emulation happens in vCPU threads or the main event loop thread. 5829 This can become a scalability bottleneck. IOThreads allow device 5830 emulation and I/O to run on other host CPUs. 5831 5832 The ``id`` parameter is a unique ID that will be used to 5833 reference this IOThread from ``-device ...,iothread=id``. 5834 Multiple devices can be assigned to an IOThread. Note that not 5835 all devices support an ``iothread`` parameter. 5836 5837 The ``query-iothreads`` QMP command lists IOThreads and reports 5838 their thread IDs so that the user can configure host CPU 5839 pinning/affinity. 5840 5841 IOThreads use an adaptive polling algorithm to reduce event loop 5842 latency. Instead of entering a blocking system call to monitor 5843 file descriptors and then pay the cost of being woken up when an 5844 event occurs, the polling algorithm spins waiting for events for 5845 a short time. The algorithm's default parameters are suitable 5846 for many cases but can be adjusted based on knowledge of the 5847 workload and/or host device latency. 5848 5849 The ``poll-max-ns`` parameter is the maximum number of 5850 nanoseconds to busy wait for events. Polling can be disabled by 5851 setting this value to 0. 5852 5853 The ``poll-grow`` parameter is the multiplier used to increase 5854 the polling time when the algorithm detects it is missing events 5855 due to not polling long enough. 5856 5857 The ``poll-shrink`` parameter is the divisor used to decrease 5858 the polling time when the algorithm detects it is spending too 5859 long polling without encountering events. 5860 5861 The ``aio-max-batch`` parameter is the maximum number of requests 5862 in a batch for the AIO engine, 0 means that the engine will use 5863 its default. 5864 5865 The IOThread parameters can be modified at run-time using the 5866 ``qom-set`` command (where ``iothread1`` is the IOThread's 5867 ``id``): 5868 5869 :: 5870 5871 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5872ERST 5873 5874 5875HXCOMM This is the last statement. Insert new options before this line! 5876 5877#undef DEF 5878#undef DEFHEADING 5879#undef ARCHHEADING 5880
