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 If no TLS credentials are provided, the websocket connection 2520 runs in unencrypted mode. If TLS credentials are provided, the 2521 websocket connection requires encrypted client connections. 2522 2523 ``password=on|off`` 2524 Require that password based authentication is used for client 2525 connections. 2526 2527 The password must be set separately using the ``set_password`` 2528 command in the :ref:`QEMU monitor`. The 2529 syntax to change your password is: 2530 ``set_password <protocol> <password>`` where <protocol> could be 2531 either "vnc" or "spice". 2532 2533 If you would like to change <protocol> password expiration, you 2534 should use ``expire_password <protocol> <expiration-time>`` 2535 where expiration time could be one of the following options: 2536 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2537 make password expire in 60 seconds, or 1335196800 to make 2538 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2539 this date and time). 2540 2541 You can also use keywords "now" or "never" for the expiration 2542 time to allow <protocol> password to expire immediately or never 2543 expire. 2544 2545 ``password-secret=<secret-id>`` 2546 Require that password based authentication is used for client 2547 connections, using the password provided by the ``secret`` 2548 object identified by ``secret-id``. 2549 2550 ``tls-creds=ID`` 2551 Provides the ID of a set of TLS credentials to use to secure the 2552 VNC server. They will apply to both the normal VNC server socket 2553 and the websocket socket (if enabled). Setting TLS credentials 2554 will cause the VNC server socket to enable the VeNCrypt auth 2555 mechanism. The credentials should have been previously created 2556 using the ``-object tls-creds`` argument. 2557 2558 ``tls-authz=ID`` 2559 Provides the ID of the QAuthZ authorization object against which 2560 the client's x509 distinguished name will validated. This object 2561 is only resolved at time of use, so can be deleted and recreated 2562 on the fly while the VNC server is active. If missing, it will 2563 default to denying access. 2564 2565 ``sasl=on|off`` 2566 Require that the client use SASL to authenticate with the VNC 2567 server. The exact choice of authentication method used is 2568 controlled from the system / user's SASL configuration file for 2569 the 'qemu' service. This is typically found in 2570 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2571 an environment variable SASL\_CONF\_PATH can be used to make it 2572 search alternate locations for the service config. While some 2573 SASL auth methods can also provide data encryption (eg GSSAPI), 2574 it is recommended that SASL always be combined with the 'tls' 2575 and 'x509' settings to enable use of SSL and server 2576 certificates. This ensures a data encryption preventing 2577 compromise of authentication credentials. See the 2578 :ref:`VNC security` section in the System Emulation Users Guide 2579 for details on using SASL authentication. 2580 2581 ``sasl-authz=ID`` 2582 Provides the ID of the QAuthZ authorization object against which 2583 the client's SASL username will validated. This object is only 2584 resolved at time of use, so can be deleted and recreated on the 2585 fly while the VNC server is active. If missing, it will default 2586 to denying access. 2587 2588 ``acl=on|off`` 2589 Legacy method for enabling authorization of clients against the 2590 x509 distinguished name and SASL username. It results in the 2591 creation of two ``authz-list`` objects with IDs of 2592 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2593 objects must be configured with the HMP ACL commands. 2594 2595 This option is deprecated and should no longer be used. The new 2596 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2597 2598 ``lossy=on|off`` 2599 Enable lossy compression methods (gradient, JPEG, ...). If this 2600 option is set, VNC client may receive lossy framebuffer updates 2601 depending on its encoding settings. Enabling this option can 2602 save a lot of bandwidth at the expense of quality. 2603 2604 ``non-adaptive=on|off`` 2605 Disable adaptive encodings. Adaptive encodings are enabled by 2606 default. An adaptive encoding will try to detect frequently 2607 updated screen regions, and send updates in these regions using 2608 a lossy encoding (like JPEG). This can be really helpful to save 2609 bandwidth when playing videos. Disabling adaptive encodings 2610 restores the original static behavior of encodings like Tight. 2611 2612 ``share=[allow-exclusive|force-shared|ignore]`` 2613 Set display sharing policy. 'allow-exclusive' allows clients to 2614 ask for exclusive access. As suggested by the rfb spec this is 2615 implemented by dropping other connections. Connecting multiple 2616 clients in parallel requires all clients asking for a shared 2617 session (vncviewer: -shared switch). This is the default. 2618 'force-shared' disables exclusive client access. Useful for 2619 shared desktop sessions, where you don't want someone forgetting 2620 specify -shared disconnect everybody else. 'ignore' completely 2621 ignores the shared flag and allows everybody connect 2622 unconditionally. Doesn't conform to the rfb spec but is 2623 traditional QEMU behavior. 2624 2625 ``key-delay-ms`` 2626 Set keyboard delay, for key down and key up events, in 2627 milliseconds. Default is 10. Keyboards are low-bandwidth 2628 devices, so this slowdown can help the device and guest to keep 2629 up and not lose events in case events are arriving in bulk. 2630 Possible causes for the latter are flaky network connections, or 2631 scripts for automated testing. 2632 2633 ``audiodev=audiodev`` 2634 Use the specified audiodev when the VNC client requests audio 2635 transmission. When not using an -audiodev argument, this option 2636 must be omitted, otherwise is must be present and specify a 2637 valid audiodev. 2638 2639 ``power-control=on|off`` 2640 Permit the remote client to issue shutdown, reboot or reset power 2641 control requests. 2642ERST 2643 2644ARCHHEADING(, QEMU_ARCH_I386) 2645 2646ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2647 2648DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2649 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2650 QEMU_ARCH_I386) 2651SRST 2652``-win2k-hack`` 2653 Use it when installing Windows 2000 to avoid a disk full bug. After 2654 Windows 2000 is installed, you no longer need this option (this 2655 option slows down the IDE transfers). Synonym of ``-global 2656 ide-device.win2k-install-hack=on``. 2657ERST 2658 2659DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2660 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2661 QEMU_ARCH_I386) 2662SRST 2663``-no-fd-bootchk`` 2664 Disable boot signature checking for floppy disks in BIOS. May be 2665 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2666ERST 2667 2668DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2669 "-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" 2670 " ACPI table description\n", QEMU_ARCH_I386) 2671SRST 2672``-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]...]`` 2673 Add ACPI table with specified header fields and context from 2674 specified files. For file=, take whole ACPI table from the specified 2675 files, including all ACPI headers (possible overridden by other 2676 options). For data=, only data portion of the table is used, all 2677 header information is specified in the command line. If a SLIC table 2678 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2679 fields will override the same in the RSDT and the FADT (a.k.a. 2680 FACP), in order to ensure the field matches required by the 2681 Microsoft SLIC spec and the ACPI spec. 2682ERST 2683 2684DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2685 "-smbios file=binary\n" 2686 " load SMBIOS entry from binary file\n" 2687 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2688 " [,uefi=on|off]\n" 2689 " specify SMBIOS type 0 fields\n" 2690 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2691 " [,uuid=uuid][,sku=str][,family=str]\n" 2692 " specify SMBIOS type 1 fields\n" 2693 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2694 " [,asset=str][,location=str]\n" 2695 " specify SMBIOS type 2 fields\n" 2696 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2697 " [,sku=str]\n" 2698 " specify SMBIOS type 3 fields\n" 2699 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2700 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2701 " [,processor-family=%d,processor-id=%d]\n" 2702 " specify SMBIOS type 4 fields\n" 2703 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2704 " specify SMBIOS type 8 fields\n" 2705 "-smbios type=11[,value=str][,path=filename]\n" 2706 " specify SMBIOS type 11 fields\n" 2707 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2708 " [,asset=str][,part=str][,speed=%d]\n" 2709 " specify SMBIOS type 17 fields\n" 2710 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2711 " specify SMBIOS type 41 fields\n", 2712 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2713SRST 2714``-smbios file=binary`` 2715 Load SMBIOS entry from binary file. 2716 2717``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2718 Specify SMBIOS type 0 fields 2719 2720``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2721 Specify SMBIOS type 1 fields 2722 2723``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2724 Specify SMBIOS type 2 fields 2725 2726``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2727 Specify SMBIOS type 3 fields 2728 2729``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2730 Specify SMBIOS type 4 fields 2731 2732``-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]`` 2733 Specify SMBIOS type 9 fields 2734 2735``-smbios type=11[,value=str][,path=filename]`` 2736 Specify SMBIOS type 11 fields 2737 2738 This argument can be repeated multiple times, and values are added in the order they are parsed. 2739 Applications intending to use OEM strings data are encouraged to use their application name as 2740 a prefix for the value string. This facilitates passing information for multiple applications 2741 concurrently. 2742 2743 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2744 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2745 2746 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2747 the SMBIOS table in the order in which they appear. 2748 2749 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2750 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2751 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2752 data set, for example, by specifying the serial ID of a block device. 2753 2754 An example passing three strings is 2755 2756 .. parsed-literal:: 2757 2758 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2759 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2760 path=/some/file/with/oemstringsdata.txt 2761 2762 In the guest OS this is visible with the ``dmidecode`` command 2763 2764 .. parsed-literal:: 2765 2766 $ dmidecode -t 11 2767 Handle 0x0E00, DMI type 11, 5 bytes 2768 OEM Strings 2769 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2770 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2771 String 3: myapp:some extra data 2772 2773 2774``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2775 Specify SMBIOS type 17 fields 2776 2777``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2778 Specify SMBIOS type 41 fields 2779 2780 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2781 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2782 position on the PCI bus. 2783 2784 Here is an example of use: 2785 2786 .. parsed-literal:: 2787 2788 -netdev user,id=internet \\ 2789 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2790 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2791 2792 In the guest OS, the device should then appear as ``eno1``: 2793 2794 ..parsed-literal:: 2795 2796 $ ip -brief l 2797 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2798 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2799 2800 Currently, the PCI device has to be attached to the root bus. 2801 2802ERST 2803 2804DEFHEADING() 2805 2806DEFHEADING(Network options:) 2807 2808DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2809#ifdef CONFIG_SLIRP 2810 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2811 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2812 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2813 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2814 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2815#ifndef _WIN32 2816 "[,smb=dir[,smbserver=addr]]\n" 2817#endif 2818 " configure a user mode network backend with ID 'str',\n" 2819 " its DHCP server and optional services\n" 2820#endif 2821#ifdef _WIN32 2822 "-netdev tap,id=str,ifname=name\n" 2823 " configure a host TAP network backend with ID 'str'\n" 2824#else 2825 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2826 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2827 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2828 " [,poll-us=n]\n" 2829 " configure a host TAP network backend with ID 'str'\n" 2830 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2831 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2832 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2833 " to deconfigure it\n" 2834 " use '[down]script=no' to disable script execution\n" 2835 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2836 " configure it\n" 2837 " use 'fd=h' to connect to an already opened TAP interface\n" 2838 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2839 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2840 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2841 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2842 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2843 " use vhost=on to enable experimental in kernel accelerator\n" 2844 " (only has effect for virtio guests which use MSIX)\n" 2845 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2846 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2847 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2848 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2849 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2850 " spent on busy polling for vhost net\n" 2851 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2852 " configure a host TAP network backend with ID 'str' that is\n" 2853 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2854 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2855#endif 2856#ifdef __linux__ 2857 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2858 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2859 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2860 " [,rxcookie=rxcookie][,offset=offset]\n" 2861 " configure a network backend with ID 'str' connected to\n" 2862 " an Ethernet over L2TPv3 pseudowire.\n" 2863 " Linux kernel 3.3+ as well as most routers can talk\n" 2864 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2865 " VM to a router and even VM to Host. It is a nearly-universal\n" 2866 " standard (RFC3931). Note - this implementation uses static\n" 2867 " pre-configured tunnels (same as the Linux kernel).\n" 2868 " use 'src=' to specify source address\n" 2869 " use 'dst=' to specify destination address\n" 2870 " use 'udp=on' to specify udp encapsulation\n" 2871 " use 'srcport=' to specify source udp port\n" 2872 " use 'dstport=' to specify destination udp port\n" 2873 " use 'ipv6=on' to force v6\n" 2874 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2875 " well as a weak security measure\n" 2876 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2877 " use 'txcookie=0x012345678' to specify a txcookie\n" 2878 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2879 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2880 " use 'pincounter=on' to work around broken counter handling in peer\n" 2881 " use 'offset=X' to add an extra offset between header and data\n" 2882#endif 2883 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2884 " configure a network backend to connect to another network\n" 2885 " using a socket connection\n" 2886 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2887 " configure a network backend to connect to a multicast maddr and port\n" 2888 " use 'localaddr=addr' to specify the host address to send packets from\n" 2889 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2890 " configure a network backend to connect to another network\n" 2891 " using an UDP tunnel\n" 2892 "-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" 2893 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2894 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2895 " configure a network backend to connect to another network\n" 2896 " using a socket connection in stream mode.\n" 2897 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2898 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2899 " configure a network backend to connect to a multicast maddr and port\n" 2900 " use ``local.host=addr`` to specify the host address to send packets from\n" 2901 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2902 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2903 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2904 " configure a network backend to connect to another network\n" 2905 " using an UDP tunnel\n" 2906#ifdef CONFIG_VDE 2907 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2908 " configure a network backend to connect to port 'n' of a vde switch\n" 2909 " running on host and listening for incoming connections on 'socketpath'.\n" 2910 " Use group 'groupname' and mode 'octalmode' to change default\n" 2911 " ownership and permissions for communication port.\n" 2912#endif 2913#ifdef CONFIG_NETMAP 2914 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2915 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2916 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2917 " netmap device, defaults to '/dev/netmap')\n" 2918#endif 2919#ifdef CONFIG_AF_XDP 2920 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2921 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2922 " attach to the existing network interface 'name' with AF_XDP socket\n" 2923 " use 'mode=MODE' to specify an XDP program attach mode\n" 2924 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2925 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2926 " with inhibit=on,\n" 2927 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2928 " added to a socket map in XDP program. One socket per queue.\n" 2929 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2930 " use 'start-queue=m' to specify the first queue that should be used\n" 2931#endif 2932#ifdef CONFIG_POSIX 2933 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2934 " configure a vhost-user network, backed by a chardev 'dev'\n" 2935#endif 2936#ifdef __linux__ 2937 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2938 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2939 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2940 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2941#endif 2942#ifdef CONFIG_VMNET 2943 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2944 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2945 " configure a vmnet network backend in host mode with ID 'str',\n" 2946 " isolate this interface from others with 'isolated',\n" 2947 " configure the address range and choose a subnet mask,\n" 2948 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2949 " vmnet-host interfaces within this isolated network\n" 2950 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2951 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2952 " configure a vmnet network backend in shared mode with ID 'str',\n" 2953 " configure the address range and choose a subnet mask,\n" 2954 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2955 " isolate this interface from others with 'isolated'\n" 2956 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2957 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2958 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2959 " isolate this interface from others with 'isolated'\n" 2960#endif 2961 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2962 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2963DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2964 "-nic [tap|bridge|" 2965#ifdef CONFIG_SLIRP 2966 "user|" 2967#endif 2968#ifdef __linux__ 2969 "l2tpv3|" 2970#endif 2971#ifdef CONFIG_VDE 2972 "vde|" 2973#endif 2974#ifdef CONFIG_NETMAP 2975 "netmap|" 2976#endif 2977#ifdef CONFIG_AF_XDP 2978 "af-xdp|" 2979#endif 2980#ifdef CONFIG_POSIX 2981 "vhost-user|" 2982#endif 2983#ifdef CONFIG_VMNET 2984 "vmnet-host|vmnet-shared|vmnet-bridged|" 2985#endif 2986 "socket][,option][,...][mac=macaddr]\n" 2987 " initialize an on-board / default host NIC (using MAC address\n" 2988 " macaddr) and connect it to the given host network backend\n" 2989 "-nic none use it alone to have zero network devices (the default is to\n" 2990 " provided a 'user' network connection)\n", 2991 QEMU_ARCH_ALL) 2992DEF("net", HAS_ARG, QEMU_OPTION_net, 2993 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2994 " configure or create an on-board (or machine default) NIC and\n" 2995 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2996 "-net [" 2997#ifdef CONFIG_SLIRP 2998 "user|" 2999#endif 3000 "tap|" 3001 "bridge|" 3002#ifdef CONFIG_VDE 3003 "vde|" 3004#endif 3005#ifdef CONFIG_NETMAP 3006 "netmap|" 3007#endif 3008#ifdef CONFIG_AF_XDP 3009 "af-xdp|" 3010#endif 3011#ifdef CONFIG_VMNET 3012 "vmnet-host|vmnet-shared|vmnet-bridged|" 3013#endif 3014 "socket][,option][,option][,...]\n" 3015 " old way to initialize a host network interface\n" 3016 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3017SRST 3018``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3019 This option is a shortcut for configuring both the on-board 3020 (default) guest NIC hardware and the host network backend in one go. 3021 The host backend options are the same as with the corresponding 3022 ``-netdev`` options below. The guest NIC model can be set with 3023 ``model=modelname``. Use ``model=help`` to list the available device 3024 types. The hardware MAC address can be set with ``mac=macaddr``. 3025 3026 The following two example do exactly the same, to show how ``-nic`` 3027 can be used to shorten the command line length: 3028 3029 .. parsed-literal:: 3030 3031 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3032 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3033 3034``-nic none`` 3035 Indicate that no network devices should be configured. It is used to 3036 override the default configuration (default NIC with "user" host 3037 network backend) which is activated if no other networking options 3038 are provided. 3039 3040``-netdev user,id=id[,option][,option][,...]`` 3041 Configure user mode host network backend which requires no 3042 administrator privilege to run. Valid options are: 3043 3044 ``id=id`` 3045 Assign symbolic name for use in monitor commands. 3046 3047 ``ipv4=on|off and ipv6=on|off`` 3048 Specify that either IPv4 or IPv6 must be enabled. If neither is 3049 specified both protocols are enabled. 3050 3051 ``net=addr[/mask]`` 3052 Set IP network address the guest will see. Optionally specify 3053 the netmask, either in the form a.b.c.d or as number of valid 3054 top-most bits. Default is 10.0.2.0/24. 3055 3056 ``host=addr`` 3057 Specify the guest-visible address of the host. Default is the 3058 2nd IP in the guest network, i.e. x.x.x.2. 3059 3060 ``ipv6-net=addr[/int]`` 3061 Set IPv6 network address the guest will see (default is 3062 fec0::/64). The network prefix is given in the usual hexadecimal 3063 IPv6 address notation. The prefix size is optional, and is given 3064 as the number of valid top-most bits (default is 64). 3065 3066 ``ipv6-host=addr`` 3067 Specify the guest-visible IPv6 address of the host. Default is 3068 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3069 3070 ``restrict=on|off`` 3071 If this option is enabled, the guest will be isolated, i.e. it 3072 will not be able to contact the host and no guest IP packets 3073 will be routed over the host to the outside. This option does 3074 not affect any explicitly set forwarding rules. 3075 3076 ``hostname=name`` 3077 Specifies the client hostname reported by the built-in DHCP 3078 server. 3079 3080 ``dhcpstart=addr`` 3081 Specify the first of the 16 IPs the built-in DHCP server can 3082 assign. Default is the 15th to 31st IP in the guest network, 3083 i.e. x.x.x.15 to x.x.x.31. 3084 3085 ``dns=addr`` 3086 Specify the guest-visible address of the virtual nameserver. The 3087 address must be different from the host address. Default is the 3088 3rd IP in the guest network, i.e. x.x.x.3. 3089 3090 ``ipv6-dns=addr`` 3091 Specify the guest-visible address of the IPv6 virtual 3092 nameserver. The address must be different from the host address. 3093 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3094 3095 ``dnssearch=domain`` 3096 Provides an entry for the domain-search list sent by the 3097 built-in DHCP server. More than one domain suffix can be 3098 transmitted by specifying this option multiple times. If 3099 supported, this will cause the guest to automatically try to 3100 append the given domain suffix(es) in case a domain name can not 3101 be resolved. 3102 3103 Example: 3104 3105 .. parsed-literal:: 3106 3107 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3108 3109 ``domainname=domain`` 3110 Specifies the client domain name reported by the built-in DHCP 3111 server. 3112 3113 ``tftp=dir`` 3114 When using the user mode network stack, activate a built-in TFTP 3115 server. The files in dir will be exposed as the root of a TFTP 3116 server. The TFTP client on the guest must be configured in 3117 binary mode (use the command ``bin`` of the Unix TFTP client). 3118 The built-in TFTP server is read-only; it does not implement any 3119 command for writing files. QEMU will not write to this directory. 3120 3121 ``tftp-server-name=name`` 3122 In BOOTP reply, broadcast name as the "TFTP server name" 3123 (RFC2132 option 66). This can be used to advise the guest to 3124 load boot files or configurations from a different server than 3125 the host address. 3126 3127 ``bootfile=file`` 3128 When using the user mode network stack, broadcast file as the 3129 BOOTP filename. In conjunction with ``tftp``, this can be used 3130 to network boot a guest from a local directory. 3131 3132 Example (using pxelinux): 3133 3134 .. parsed-literal:: 3135 3136 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3137 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3138 3139 ``smb=dir[,smbserver=addr]`` 3140 When using the user mode network stack, activate a built-in SMB 3141 server so that Windows OSes can access to the host files in 3142 ``dir`` transparently. The IP address of the SMB server can be 3143 set to addr. By default the 4th IP in the guest network is used, 3144 i.e. x.x.x.4. 3145 3146 In the guest Windows OS, the line: 3147 3148 :: 3149 3150 10.0.2.4 smbserver 3151 3152 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3153 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3154 NT/2000). 3155 3156 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3157 3158 Note that a SAMBA server must be installed on the host OS. 3159 3160 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3161 Redirect incoming TCP or UDP connections to the host port 3162 hostport to the guest IP address guestaddr on guest port 3163 guestport. If guestaddr is not specified, its value is x.x.x.15 3164 (default first address given by the built-in DHCP server). By 3165 specifying hostaddr, the rule can be bound to a specific host 3166 interface. If no connection type is set, TCP is used. This 3167 option can be given multiple times. 3168 3169 For example, to redirect host X11 connection from screen 1 to 3170 guest screen 0, use the following: 3171 3172 .. parsed-literal:: 3173 3174 # on the host 3175 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3176 # this host xterm should open in the guest X11 server 3177 xterm -display :1 3178 3179 To redirect telnet connections from host port 5555 to telnet 3180 port on the guest, use the following: 3181 3182 .. parsed-literal:: 3183 3184 # on the host 3185 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3186 telnet localhost 5555 3187 3188 Then when you use on the host ``telnet localhost 5555``, you 3189 connect to the guest telnet server. 3190 3191 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3192 Forward guest TCP connections to the IP address server on port 3193 port to the character device dev or to a program executed by 3194 cmd:command which gets spawned for each connection. This option 3195 can be given multiple times. 3196 3197 You can either use a chardev directly and have that one used 3198 throughout QEMU's lifetime, like in the following example: 3199 3200 .. parsed-literal:: 3201 3202 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3203 # the guest accesses it 3204 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3205 3206 Or you can execute a command on every TCP connection established 3207 by the guest, so that QEMU behaves similar to an inetd process 3208 for that virtual server: 3209 3210 .. parsed-literal:: 3211 3212 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3213 # and connect the TCP stream to its stdin/stdout 3214 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3215 3216``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3217 Configure a host TAP network backend with ID id. 3218 3219 Use the network script file to configure it and the network script 3220 dfile to deconfigure it. If name is not provided, the OS 3221 automatically provides one. The default network configure script is 3222 ``/etc/qemu-ifup`` and the default network deconfigure script is 3223 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3224 disable script execution. 3225 3226 If running QEMU as an unprivileged user, use the network helper 3227 to configure the TAP interface and attach it to the bridge. 3228 The default network helper executable is 3229 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3230 ``br0``. 3231 3232 ``fd``\ =h can be used to specify the handle of an already opened 3233 host TAP interface. 3234 3235 Examples: 3236 3237 .. parsed-literal:: 3238 3239 #launch a QEMU instance with the default network script 3240 |qemu_system| linux.img -nic tap 3241 3242 .. parsed-literal:: 3243 3244 #launch a QEMU instance with two NICs, each one connected 3245 #to a TAP device 3246 |qemu_system| linux.img \\ 3247 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3248 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3249 3250 .. parsed-literal:: 3251 3252 #launch a QEMU instance with the default network helper to 3253 #connect a TAP device to bridge br0 3254 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3255 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3256 3257``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3258 Connect a host TAP network interface to a host bridge device. 3259 3260 Use the network helper helper to configure the TAP interface and 3261 attach it to the bridge. The default network helper executable is 3262 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3263 ``br0``. 3264 3265 Examples: 3266 3267 .. parsed-literal:: 3268 3269 #launch a QEMU instance with the default network helper to 3270 #connect a TAP device to bridge br0 3271 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3272 3273 .. parsed-literal:: 3274 3275 #launch a QEMU instance with the default network helper to 3276 #connect a TAP device to bridge qemubr0 3277 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3278 3279``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3280 This host network backend can be used to connect the guest's network 3281 to another QEMU virtual machine using a TCP socket connection. If 3282 ``listen`` is specified, QEMU waits for incoming connections on port 3283 (host is optional). ``connect`` is used to connect to another QEMU 3284 instance using the ``listen`` option. ``fd``\ =h specifies an 3285 already opened TCP socket. 3286 3287 Example: 3288 3289 .. parsed-literal:: 3290 3291 # launch a first QEMU instance 3292 |qemu_system| linux.img \\ 3293 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3294 -netdev socket,id=n1,listen=:1234 3295 # connect the network of this instance to the network of the first instance 3296 |qemu_system| linux.img \\ 3297 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3298 -netdev socket,id=n2,connect=127.0.0.1:1234 3299 3300``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3301 Configure a socket host network backend to share the guest's network 3302 traffic with another QEMU virtual machines using a UDP multicast 3303 socket, effectively making a bus for every QEMU with same multicast 3304 address maddr and port. NOTES: 3305 3306 1. Several QEMU can be running on different hosts and share same bus 3307 (assuming correct multicast setup for these hosts). 3308 3309 2. mcast support is compatible with User Mode Linux (argument 3310 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3311 3312 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3313 3314 Example: 3315 3316 .. parsed-literal:: 3317 3318 # launch one QEMU instance 3319 |qemu_system| linux.img \\ 3320 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3321 -netdev socket,id=n1,mcast=230.0.0.1:1234 3322 # launch another QEMU instance on same "bus" 3323 |qemu_system| linux.img \\ 3324 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3325 -netdev socket,id=n2,mcast=230.0.0.1:1234 3326 # launch yet another QEMU instance on same "bus" 3327 |qemu_system| linux.img \\ 3328 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3329 -netdev socket,id=n3,mcast=230.0.0.1:1234 3330 3331 Example (User Mode Linux compat.): 3332 3333 .. parsed-literal:: 3334 3335 # launch QEMU instance (note mcast address selected is UML's default) 3336 |qemu_system| linux.img \\ 3337 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3338 -netdev socket,id=n1,mcast=239.192.168.1:1102 3339 # launch UML 3340 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3341 3342 Example (send packets from host's 1.2.3.4): 3343 3344 .. parsed-literal:: 3345 3346 |qemu_system| linux.img \\ 3347 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3348 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3349 3350``-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]`` 3351 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3352 is a popular protocol to transport Ethernet (and other Layer 2) data 3353 frames between two systems. It is present in routers, firewalls and 3354 the Linux kernel (from version 3.3 onwards). 3355 3356 This transport allows a VM to communicate to another VM, router or 3357 firewall directly. 3358 3359 ``src=srcaddr`` 3360 source address (mandatory) 3361 3362 ``dst=dstaddr`` 3363 destination address (mandatory) 3364 3365 ``udp`` 3366 select udp encapsulation (default is ip). 3367 3368 ``srcport=srcport`` 3369 source udp port. 3370 3371 ``dstport=dstport`` 3372 destination udp port. 3373 3374 ``ipv6`` 3375 force v6, otherwise defaults to v4. 3376 3377 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3378 Cookies are a weak form of security in the l2tpv3 specification. 3379 Their function is mostly to prevent misconfiguration. By default 3380 they are 32 bit. 3381 3382 ``cookie64`` 3383 Set cookie size to 64 bit instead of the default 32 3384 3385 ``counter=off`` 3386 Force a 'cut-down' L2TPv3 with no counter as in 3387 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3388 3389 ``pincounter=on`` 3390 Work around broken counter handling in peer. This may also help 3391 on networks which have packet reorder. 3392 3393 ``offset=offset`` 3394 Add an extra offset between header and data 3395 3396 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3397 the bridge br-lan on the remote Linux host 1.2.3.4: 3398 3399 .. parsed-literal:: 3400 3401 # Setup tunnel on linux host using raw ip as encapsulation 3402 # on 1.2.3.4 3403 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3404 encap udp udp_sport 16384 udp_dport 16384 3405 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3406 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3407 ifconfig vmtunnel0 mtu 1500 3408 ifconfig vmtunnel0 up 3409 brctl addif br-lan vmtunnel0 3410 3411 3412 # on 4.3.2.1 3413 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3414 3415 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3416 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3417 3418``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3419 Configure VDE backend to connect to PORT n of a vde switch running 3420 on host and listening for incoming connections on socketpath. Use 3421 GROUP groupname and MODE octalmode to change default ownership and 3422 permissions for communication port. This option is only available if 3423 QEMU has been compiled with vde support enabled. 3424 3425 Example: 3426 3427 .. parsed-literal:: 3428 3429 # launch vde switch 3430 vde_switch -F -sock /tmp/myswitch 3431 # launch QEMU instance 3432 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3433 3434``-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]`` 3435 Configure AF_XDP backend to connect to a network interface 'name' 3436 using AF_XDP socket. A specific program attach mode for a default 3437 XDP program can be forced with 'mode', defaults to best-effort, 3438 where the likely most performant mode will be in use. Number of queues 3439 'n' should generally match the number or queues in the interface, 3440 defaults to 1. Traffic arriving on non-configured device queues will 3441 not be delivered to the network backend. 3442 3443 .. parsed-literal:: 3444 3445 # set number of queues to 4 3446 ethtool -L eth0 combined 4 3447 # launch QEMU instance 3448 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3449 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3450 3451 'start-queue' option can be specified if a particular range of queues 3452 [m, m + n] should be in use. For example, this is may be necessary in 3453 order to use certain NICs in native mode. Kernel allows the driver to 3454 create a separate set of XDP queues on top of regular ones, and only 3455 these queues can be used for AF_XDP sockets. NICs that work this way 3456 may also require an additional traffic redirection with ethtool to these 3457 special queues. 3458 3459 .. parsed-literal:: 3460 3461 # set number of queues to 1 3462 ethtool -L eth0 combined 1 3463 # redirect all the traffic to the second queue (id: 1) 3464 # note: drivers may require non-empty key/mask pair. 3465 ethtool -N eth0 flow-type ether \\ 3466 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3467 ethtool -N eth0 flow-type ether \\ 3468 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3469 # launch QEMU instance 3470 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3471 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3472 3473 XDP program can also be loaded externally. In this case 'inhibit' option 3474 should be set to 'on' and 'sock-fds' provided with file descriptors for 3475 already open but not bound XDP sockets already added to a socket map for 3476 corresponding queues. One socket per queue. 3477 3478 .. parsed-literal:: 3479 3480 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3481 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3482 3483``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3484 Establish a vhost-user netdev, backed by a chardev id. The chardev 3485 should be a unix domain socket backed one. The vhost-user uses a 3486 specifically defined protocol to pass vhost ioctl replacement 3487 messages to an application on the other end of the socket. On 3488 non-MSIX guests, the feature can be forced with vhostforce. Use 3489 'queues=n' to specify the number of queues to be created for 3490 multiqueue vhost-user. 3491 3492 Example: 3493 3494 :: 3495 3496 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3497 -numa node,memdev=mem \ 3498 -chardev socket,id=chr0,path=/path/to/socket \ 3499 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3500 -device virtio-net-pci,netdev=net0 3501 3502``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3503 Establish a vhost-vdpa netdev. 3504 3505 vDPA device is a device that uses a datapath which complies with 3506 the virtio specifications with a vendor specific control path. 3507 vDPA devices can be both physically located on the hardware or 3508 emulated by software. 3509 3510``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3511 Create a hub port on the emulated hub with ID hubid. 3512 3513 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3514 instead of a single netdev. Alternatively, you can also connect the 3515 hubport to another netdev with ID nd by using the ``netdev=nd`` 3516 option. 3517 3518``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3519 Legacy option to configure or create an on-board (or machine 3520 default) Network Interface Card(NIC) and connect it either to the 3521 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3522 If model is omitted, then the default NIC model associated with the 3523 machine type is used. Note that the default NIC model may change in 3524 future QEMU releases, so it is highly recommended to always specify 3525 a model. Optionally, the MAC address can be changed to mac, the 3526 device address set to addr (PCI cards only), and a name can be 3527 assigned for use in monitor commands. Optionally, for PCI cards, you 3528 can specify the number v of MSI-X vectors that the card should have; 3529 this option currently only affects virtio cards; set v = 0 to 3530 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3531 created. QEMU can emulate several different models of network card. 3532 Use ``-net nic,model=help`` for a list of available devices for your 3533 target. 3534 3535``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3536 Configure a host network backend (with the options corresponding to 3537 the same ``-netdev`` option) and connect it to the emulated hub 0 3538 (the default hub). Use name to specify the name of the hub port. 3539ERST 3540 3541DEFHEADING() 3542 3543DEFHEADING(Character device options:) 3544 3545DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3546 "-chardev help\n" 3547 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3548 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3549 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3550 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3551 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3552 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3553 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3554 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3555 " [,logfile=PATH][,logappend=on|off]\n" 3556 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3557 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3558 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3559 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3560 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3561 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3562#ifdef _WIN32 3563 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3564 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3565#else 3566 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3567 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3568#endif 3569#ifdef CONFIG_BRLAPI 3570 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3571#endif 3572#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3573 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3574 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3575#endif 3576#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3577 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3578#endif 3579#if defined(CONFIG_SPICE) 3580 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3581 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3582#endif 3583 , QEMU_ARCH_ALL 3584) 3585 3586SRST 3587The general form of a character device option is: 3588 3589``-chardev backend,id=id[,mux=on|off][,options]`` 3590 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3591 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3592 ``pty``, ``stdio``, ``braille``, ``parallel``, 3593 ``spicevmc``, ``spiceport``. The specific backend will determine the 3594 applicable options. 3595 3596 Use ``-chardev help`` to print all available chardev backend types. 3597 3598 All devices must have an id, which can be any string up to 127 3599 characters long. It is used to uniquely identify this device in 3600 other command line directives. 3601 3602 A character device may be used in multiplexing mode by multiple 3603 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3604 a "1:N" device, and here the "1" end is your specified chardev 3605 backend, and the "N" end is the various parts of QEMU that can talk 3606 to a chardev. If you create a chardev with ``id=myid`` and 3607 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3608 and you can then configure multiple front ends to use that chardev 3609 ID for their input/output. Up to four different front ends can be 3610 connected to a single multiplexed chardev. (Without multiplexing 3611 enabled, a chardev can only be used by a single front end.) For 3612 instance you could use this to allow a single stdio chardev to be 3613 used by two serial ports and the QEMU monitor: 3614 3615 :: 3616 3617 -chardev stdio,mux=on,id=char0 \ 3618 -mon chardev=char0,mode=readline \ 3619 -serial chardev:char0 \ 3620 -serial chardev:char0 3621 3622 You can have more than one multiplexer in a system configuration; 3623 for instance you could have a TCP port multiplexed between UART 0 3624 and UART 1, and stdio multiplexed between the QEMU monitor and a 3625 parallel port: 3626 3627 :: 3628 3629 -chardev stdio,mux=on,id=char0 \ 3630 -mon chardev=char0,mode=readline \ 3631 -parallel chardev:char0 \ 3632 -chardev tcp,...,mux=on,id=char1 \ 3633 -serial chardev:char1 \ 3634 -serial chardev:char1 3635 3636 When you're using a multiplexed character device, some escape 3637 sequences are interpreted in the input. See the chapter about 3638 :ref:`keys in the character backend multiplexer` in the 3639 System Emulation Users Guide for more details. 3640 3641 Note that some other command line options may implicitly create 3642 multiplexed character backends; for instance ``-serial mon:stdio`` 3643 creates a multiplexed stdio backend connected to the serial port and 3644 the QEMU monitor, and ``-nographic`` also multiplexes the console 3645 and the monitor to stdio. 3646 3647 There is currently no support for multiplexing in the other 3648 direction (where a single QEMU front end takes input and output from 3649 multiple chardevs). 3650 3651 Every backend supports the ``logfile`` option, which supplies the 3652 path to a file to record all data transmitted via the backend. The 3653 ``logappend`` option controls whether the log file will be truncated 3654 or appended to when opened. 3655 3656The available backends are: 3657 3658``-chardev null,id=id`` 3659 A void device. This device will not emit any data, and will drop any 3660 data it receives. The null backend does not take any options. 3661 3662``-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]`` 3663 Create a two-way stream socket, which can be either a TCP or a unix 3664 socket. A unix socket will be created if ``path`` is specified. 3665 Behaviour is undefined if TCP options are specified for a unix 3666 socket. 3667 3668 ``server=on|off`` specifies that the socket shall be a listening socket. 3669 3670 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3671 to connect to a listening socket. 3672 3673 ``telnet=on|off`` specifies that traffic on the socket should interpret 3674 telnet escape sequences. 3675 3676 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3677 communication. 3678 3679 ``reconnect`` sets the timeout for reconnecting on non-server 3680 sockets when the remote end goes away. qemu will delay this many 3681 seconds and then attempt to reconnect. Zero disables reconnecting, 3682 and is the default. 3683 3684 ``tls-creds`` requests enablement of the TLS protocol for 3685 encryption, and specifies the id of the TLS credentials to use for 3686 the handshake. The credentials must be previously created with the 3687 ``-object tls-creds`` argument. 3688 3689 ``tls-auth`` provides the ID of the QAuthZ authorization object 3690 against which the client's x509 distinguished name will be 3691 validated. This object is only resolved at time of use, so can be 3692 deleted and recreated on the fly while the chardev server is active. 3693 If missing, it will default to denying access. 3694 3695 TCP and unix socket options are given below: 3696 3697 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3698 ``host`` for a listening socket specifies the local address to 3699 be bound. For a connecting socket species the remote host to 3700 connect to. ``host`` is optional for listening sockets. If not 3701 specified it defaults to ``0.0.0.0``. 3702 3703 ``port`` for a listening socket specifies the local port to be 3704 bound. For a connecting socket specifies the port on the remote 3705 host to connect to. ``port`` can be given as either a port 3706 number or a service name. ``port`` is required. 3707 3708 ``to`` is only relevant to listening sockets. If it is 3709 specified, and ``port`` cannot be bound, QEMU will attempt to 3710 bind to subsequent ports up to and including ``to`` until it 3711 succeeds. ``to`` must be specified as a port number. 3712 3713 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3714 or IPv6 must be used. If neither is specified the socket may 3715 use either protocol. 3716 3717 ``nodelay=on|off`` disables the Nagle algorithm. 3718 3719 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3720 ``path`` specifies the local path of the unix socket. ``path`` 3721 is required. 3722 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3723 rather than the filesystem. Optional, defaults to false. 3724 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3725 rather than the full sun_path length. Optional, defaults to true. 3726 3727``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3728 Sends all traffic from the guest to a remote host over UDP. 3729 3730 ``host`` specifies the remote host to connect to. If not specified 3731 it defaults to ``localhost``. 3732 3733 ``port`` specifies the port on the remote host to connect to. 3734 ``port`` is required. 3735 3736 ``localaddr`` specifies the local address to bind to. If not 3737 specified it defaults to ``0.0.0.0``. 3738 3739 ``localport`` specifies the local port to bind to. If not specified 3740 any available local port will be used. 3741 3742 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3743 If neither is specified the device may use either protocol. 3744 3745``-chardev msmouse,id=id`` 3746 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3747 does not take any options. 3748 3749``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3750 Connect to a QEMU text console. ``vc`` may optionally be given a 3751 specific size. 3752 3753 ``width`` and ``height`` specify the width and height respectively 3754 of the console, in pixels. 3755 3756 ``cols`` and ``rows`` specify that the console be sized to fit a 3757 text console with the given dimensions. 3758 3759``-chardev ringbuf,id=id[,size=size]`` 3760 Create a ring buffer with fixed size ``size``. size must be a power 3761 of two and defaults to ``64K``. 3762 3763``-chardev file,id=id,path=path[,input-path=input-path]`` 3764 Log all traffic received from the guest to a file. 3765 3766 ``path`` specifies the path of the file to be opened. This file will 3767 be created if it does not already exist, and overwritten if it does. 3768 ``path`` is required. 3769 3770 If ``input-path`` is specified, this is the path of a second file 3771 which will be used for input. If ``input-path`` is not specified, 3772 no input will be available from the chardev. 3773 3774 Note that ``input-path`` is not supported on Windows hosts. 3775 3776``-chardev pipe,id=id,path=path`` 3777 Create a two-way connection to the guest. The behaviour differs 3778 slightly between Windows hosts and other hosts: 3779 3780 On Windows, a single duplex pipe will be created at 3781 ``\\.pipe\path``. 3782 3783 On other hosts, 2 pipes will be created called ``path.in`` and 3784 ``path.out``. Data written to ``path.in`` will be received by the 3785 guest. Data written by the guest can be read from ``path.out``. QEMU 3786 will not create these fifos, and requires them to be present. 3787 3788 ``path`` forms part of the pipe path as described above. ``path`` is 3789 required. 3790 3791``-chardev console,id=id`` 3792 Send traffic from the guest to QEMU's standard output. ``console`` 3793 does not take any options. 3794 3795 ``console`` is only available on Windows hosts. 3796 3797``-chardev serial,id=id,path=path`` 3798 Send traffic from the guest to a serial device on the host. 3799 3800 On Unix hosts serial will actually accept any tty device, not only 3801 serial lines. 3802 3803 ``path`` specifies the name of the serial device to open. 3804 3805``-chardev pty,id=id`` 3806 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3807 does not take any options. 3808 3809 ``pty`` is not available on Windows hosts. 3810 3811``-chardev stdio,id=id[,signal=on|off]`` 3812 Connect to standard input and standard output of the QEMU process. 3813 3814 ``signal`` controls if signals are enabled on the terminal, that 3815 includes exiting QEMU with the key sequence Control-c. This option 3816 is enabled by default, use ``signal=off`` to disable it. 3817 3818``-chardev braille,id=id`` 3819 Connect to a local BrlAPI server. ``braille`` does not take any 3820 options. 3821 3822``-chardev parallel,id=id,path=path`` 3823 \ 3824 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3825 hosts. 3826 3827 Connect to a local parallel port. 3828 3829 ``path`` specifies the path to the parallel port device. ``path`` is 3830 required. 3831 3832``-chardev spicevmc,id=id,debug=debug,name=name`` 3833 ``spicevmc`` is only available when spice support is built in. 3834 3835 ``debug`` debug level for spicevmc 3836 3837 ``name`` name of spice channel to connect to 3838 3839 Connect to a spice virtual machine channel, such as vdiport. 3840 3841``-chardev spiceport,id=id,debug=debug,name=name`` 3842 ``spiceport`` is only available when spice support is built in. 3843 3844 ``debug`` debug level for spicevmc 3845 3846 ``name`` name of spice port to connect to 3847 3848 Connect to a spice port, allowing a Spice client to handle the 3849 traffic identified by a name (preferably a fqdn). 3850ERST 3851 3852DEFHEADING() 3853 3854#ifdef CONFIG_TPM 3855DEFHEADING(TPM device options:) 3856 3857DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3858 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3859 " use path to provide path to a character device; default is /dev/tpm0\n" 3860 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3861 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3862 "-tpmdev emulator,id=id,chardev=dev\n" 3863 " configure the TPM device using chardev backend\n", 3864 QEMU_ARCH_ALL) 3865SRST 3866The general form of a TPM device option is: 3867 3868``-tpmdev backend,id=id[,options]`` 3869 The specific backend type will determine the applicable options. The 3870 ``-tpmdev`` option creates the TPM backend and requires a 3871 ``-device`` option that specifies the TPM frontend interface model. 3872 3873 Use ``-tpmdev help`` to print all available TPM backend types. 3874 3875The available backends are: 3876 3877``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3878 (Linux-host only) Enable access to the host's TPM using the 3879 passthrough driver. 3880 3881 ``path`` specifies the path to the host's TPM device, i.e., on a 3882 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3883 default ``/dev/tpm0`` is used. 3884 3885 ``cancel-path`` specifies the path to the host TPM device's sysfs 3886 entry allowing for cancellation of an ongoing TPM command. 3887 ``cancel-path`` is optional and by default QEMU will search for the 3888 sysfs entry to use. 3889 3890 Some notes about using the host's TPM with the passthrough driver: 3891 3892 The TPM device accessed by the passthrough driver must not be used 3893 by any other application on the host. 3894 3895 Since the host's firmware (BIOS/UEFI) has already initialized the 3896 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3897 the TPM again and may therefore not show a TPM-specific menu that 3898 would otherwise allow the user to configure the TPM, e.g., allow the 3899 user to enable/disable or activate/deactivate the TPM. Further, if 3900 TPM ownership is released from within a VM then the host's TPM will 3901 get disabled and deactivated. To enable and activate the TPM again 3902 afterwards, the host has to be rebooted and the user is required to 3903 enter the firmware's menu to enable and activate the TPM. If the TPM 3904 is left disabled and/or deactivated most TPM commands will fail. 3905 3906 To create a passthrough TPM use the following two options: 3907 3908 :: 3909 3910 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3911 3912 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3913 ``tpmdev=tpm0`` in the device option. 3914 3915``-tpmdev emulator,id=id,chardev=dev`` 3916 (Linux-host only) Enable access to a TPM emulator using Unix domain 3917 socket based chardev backend. 3918 3919 ``chardev`` specifies the unique ID of a character device backend 3920 that provides connection to the software TPM server. 3921 3922 To create a TPM emulator backend device with chardev socket backend: 3923 3924 :: 3925 3926 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3927ERST 3928 3929DEFHEADING() 3930 3931#endif 3932 3933DEFHEADING(Boot Image or Kernel specific:) 3934SRST 3935There are broadly 4 ways you can boot a system with QEMU. 3936 3937 - specify a firmware and let it control finding a kernel 3938 - specify a firmware and pass a hint to the kernel to boot 3939 - direct kernel image boot 3940 - manually load files into the guest's address space 3941 3942The third method is useful for quickly testing kernels but as there is 3943no firmware to pass configuration information to the kernel the 3944hardware must either be probeable, the kernel built for the exact 3945configuration or passed some configuration data (e.g. a DTB blob) 3946which tells the kernel what drivers it needs. This exact details are 3947often hardware specific. 3948 3949The final method is the most generic way of loading images into the 3950guest address space and used mostly for ``bare metal`` type 3951development where the reset vectors of the processor are taken into 3952account. 3953 3954ERST 3955 3956SRST 3957 3958For x86 machines and some other architectures ``-bios`` will generally 3959do the right thing with whatever it is given. For other machines the 3960more strict ``-pflash`` option needs an image that is sized for the 3961flash device for the given machine type. 3962 3963Please see the :ref:`system-targets-ref` section of the manual for 3964more detailed documentation. 3965 3966ERST 3967 3968DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3969 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3970SRST 3971``-bios file`` 3972 Set the filename for the BIOS. 3973ERST 3974 3975DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3976 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3977SRST 3978``-pflash file`` 3979 Use file as a parallel flash image. 3980ERST 3981 3982SRST 3983 3984The kernel options were designed to work with Linux kernels although 3985other things (like hypervisors) can be packaged up as a kernel 3986executable image. The exact format of a executable image is usually 3987architecture specific. 3988 3989The way in which the kernel is started (what address it is loaded at, 3990what if any information is passed to it via CPU registers, the state 3991of the hardware when it is started, and so on) is also architecture 3992specific. Typically it follows the specification laid down by the 3993Linux kernel for how kernels for that architecture must be started. 3994 3995ERST 3996 3997DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3998 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3999SRST 4000``-kernel bzImage`` 4001 Use bzImage as kernel image. The kernel can be either a Linux kernel 4002 or in multiboot format. 4003ERST 4004 4005DEF("append", HAS_ARG, QEMU_OPTION_append, \ 4006 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 4007SRST 4008``-append cmdline`` 4009 Use cmdline as kernel command line 4010ERST 4011 4012DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4013 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4014SRST(initrd) 4015 4016``-initrd file`` 4017 Use file as initial ram disk. 4018 4019``-initrd "file1 arg=foo,file2"`` 4020 This syntax is only available with multiboot. 4021 4022 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4023 first module. Commas can be provided in module parameters by doubling 4024 them on the command line to escape them: 4025 4026``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4027 Multiboot only. Use bzImage as the first module with 4028 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4029 and initrd.img as the second module. 4030 4031ERST 4032 4033DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4034 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4035SRST 4036``-dtb file`` 4037 Use file as a device tree binary (dtb) image and pass it to the 4038 kernel on boot. 4039ERST 4040 4041SRST 4042 4043Finally you can also manually load images directly into the address 4044space of the guest. This is most useful for developers who already 4045know the layout of their guest and take care to ensure something sane 4046will happen when the reset vector executes. 4047 4048The generic loader can be invoked by using the loader device: 4049 4050``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4051 4052there is also the guest loader which operates in a similar way but 4053tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4054the guest image is: 4055 4056``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4057 4058ERST 4059 4060DEFHEADING() 4061 4062DEFHEADING(Debug/Expert options:) 4063 4064DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4065 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4066 " Policy for handling deprecated management interfaces\n" 4067 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4068 " Policy for handling unstable management interfaces\n", 4069 QEMU_ARCH_ALL) 4070SRST 4071``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4072 Set policy for handling deprecated management interfaces (experimental): 4073 4074 ``deprecated-input=accept`` (default) 4075 Accept deprecated commands and arguments 4076 ``deprecated-input=reject`` 4077 Reject deprecated commands and arguments 4078 ``deprecated-input=crash`` 4079 Crash on deprecated commands and arguments 4080 ``deprecated-output=accept`` (default) 4081 Emit deprecated command results and events 4082 ``deprecated-output=hide`` 4083 Suppress deprecated command results and events 4084 4085 Limitation: covers only syntactic aspects of QMP. 4086 4087``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4088 Set policy for handling unstable management interfaces (experimental): 4089 4090 ``unstable-input=accept`` (default) 4091 Accept unstable commands and arguments 4092 ``unstable-input=reject`` 4093 Reject unstable commands and arguments 4094 ``unstable-input=crash`` 4095 Crash on unstable commands and arguments 4096 ``unstable-output=accept`` (default) 4097 Emit unstable command results and events 4098 ``unstable-output=hide`` 4099 Suppress unstable command results and events 4100 4101 Limitation: covers only syntactic aspects of QMP. 4102ERST 4103 4104DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4105 "-fw_cfg [name=]<name>,file=<file>\n" 4106 " add named fw_cfg entry with contents from file\n" 4107 "-fw_cfg [name=]<name>,string=<str>\n" 4108 " add named fw_cfg entry with contents from string\n", 4109 QEMU_ARCH_ALL) 4110SRST 4111``-fw_cfg [name=]name,file=file`` 4112 Add named fw\_cfg entry with contents from file file. 4113 If the filename contains comma, you must double it (for instance, 4114 "file=my,,file" to use file "my,file"). 4115 4116``-fw_cfg [name=]name,string=str`` 4117 Add named fw\_cfg entry with contents from string str. 4118 If the string contains comma, you must double it (for instance, 4119 "string=my,,string" to use file "my,string"). 4120 4121 The terminating NUL character of the contents of str will not be 4122 included as part of the fw\_cfg item data. To insert contents with 4123 embedded NUL characters, you have to use the file parameter. 4124 4125 The fw\_cfg entries are passed by QEMU through to the guest. 4126 4127 Example: 4128 4129 :: 4130 4131 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4132 4133 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4134 from ./my\_blob.bin. 4135ERST 4136 4137DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4138 "-serial dev redirect the serial port to char device 'dev'\n", 4139 QEMU_ARCH_ALL) 4140SRST 4141``-serial dev`` 4142 Redirect the virtual serial port to host character device dev. The 4143 default device is ``vc`` in graphical mode and ``stdio`` in non 4144 graphical mode. 4145 4146 This option can be used several times to simulate multiple serial 4147 ports. 4148 4149 You can use ``-serial none`` to suppress the creation of default 4150 serial devices. 4151 4152 Available character devices are: 4153 4154 ``vc[:WxH]`` 4155 Virtual console. Optionally, a width and height can be given in 4156 pixel with 4157 4158 :: 4159 4160 vc:800x600 4161 4162 It is also possible to specify width or height in characters: 4163 4164 :: 4165 4166 vc:80Cx24C 4167 4168 ``pty`` 4169 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4170 4171 ``none`` 4172 No device is allocated. Note that for machine types which 4173 emulate systems where a serial device is always present in 4174 real hardware, this may be equivalent to the ``null`` option, 4175 in that the serial device is still present but all output 4176 is discarded. For boards where the number of serial ports is 4177 truly variable, this suppresses the creation of the device. 4178 4179 ``null`` 4180 A guest will see the UART or serial device as present in the 4181 machine, but all output is discarded, and there is no input. 4182 Conceptually equivalent to redirecting the output to ``/dev/null``. 4183 4184 ``chardev:id`` 4185 Use a named character device defined with the ``-chardev`` 4186 option. 4187 4188 ``/dev/XXX`` 4189 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4190 port parameters are set according to the emulated ones. 4191 4192 ``/dev/parportN`` 4193 [Linux only, parallel port only] Use host parallel port N. 4194 Currently SPP and EPP parallel port features can be used. 4195 4196 ``file:filename`` 4197 Write output to filename. No character can be read. 4198 4199 ``stdio`` 4200 [Unix only] standard input/output 4201 4202 ``pipe:filename`` 4203 name pipe filename 4204 4205 ``COMn`` 4206 [Windows only] Use host serial port n 4207 4208 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4209 This implements UDP Net Console. When remote\_host or src\_ip 4210 are not specified they default to ``0.0.0.0``. When not using a 4211 specified src\_port a random port is automatically chosen. 4212 4213 If you just want a simple readonly console you can use 4214 ``netcat`` or ``nc``, by starting QEMU with: 4215 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4216 QEMU writes something to that port it will appear in the 4217 netconsole session. 4218 4219 If you plan to send characters back via netconsole or you want 4220 to stop and start QEMU a lot of times, you should have QEMU use 4221 the same source port each time by using something like ``-serial 4222 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4223 version of netcat which can listen to a TCP port and send and 4224 receive characters via udp. If you have a patched version of 4225 netcat which activates telnet remote echo and single char 4226 transfer, then you can use the following options to set up a 4227 netcat redirector to allow telnet on port 5555 to access the 4228 QEMU port. 4229 4230 ``QEMU Options:`` 4231 -serial udp::4555@:4556 4232 4233 ``netcat options:`` 4234 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4235 4236 ``telnet options:`` 4237 localhost 5555 4238 4239 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4240 The TCP Net Console has two modes of operation. It can send the 4241 serial I/O to a location or wait for a connection from a 4242 location. By default the TCP Net Console is sent to host at the 4243 port. If you use the ``server=on`` option QEMU will wait for a client 4244 socket application to connect to the port before continuing, 4245 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4246 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4247 option only applies if ``server=no`` is set, if the connection goes 4248 down it will attempt to reconnect at the given interval. If host 4249 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4250 time is accepted. You can use ``telnet=on`` to connect to the 4251 corresponding character device. 4252 4253 ``Example to send tcp console to 192.168.0.2 port 4444`` 4254 -serial tcp:192.168.0.2:4444 4255 4256 ``Example to listen and wait on port 4444 for connection`` 4257 -serial tcp::4444,server=on 4258 4259 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4260 -serial tcp:192.168.0.100:4444,server=on,wait=off 4261 4262 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4263 The telnet protocol is used instead of raw tcp sockets. The 4264 options work the same as if you had specified ``-serial tcp``. 4265 The difference is that the port acts like a telnet server or 4266 client using telnet option negotiation. This will also allow you 4267 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4268 supports sending the break sequence. Typically in unix telnet 4269 you do it with Control-] and then type "send break" followed by 4270 pressing the enter key. 4271 4272 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4273 The WebSocket protocol is used instead of raw tcp socket. The 4274 port acts as a WebSocket server. Client mode is not supported. 4275 4276 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4277 A unix domain socket is used instead of a tcp socket. The option 4278 works the same as if you had specified ``-serial tcp`` except 4279 the unix domain socket path is used for connections. 4280 4281 ``mon:dev_string`` 4282 This is a special option to allow the monitor to be multiplexed 4283 onto another serial port. The monitor is accessed with key 4284 sequence of Control-a and then pressing c. dev\_string should be 4285 any one of the serial devices specified above. An example to 4286 multiplex the monitor onto a telnet server listening on port 4287 4444 would be: 4288 4289 ``-serial mon:telnet::4444,server=on,wait=off`` 4290 4291 When the monitor is multiplexed to stdio in this way, Ctrl+C 4292 will not terminate QEMU any more but will be passed to the guest 4293 instead. 4294 4295 ``braille`` 4296 Braille device. This will use BrlAPI to display the braille 4297 output on a real or fake device. 4298 4299 ``msmouse`` 4300 Three button serial mouse. Configure the guest to use Microsoft 4301 protocol. 4302ERST 4303 4304DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4305 "-parallel dev redirect the parallel port to char device 'dev'\n", 4306 QEMU_ARCH_ALL) 4307SRST 4308``-parallel dev`` 4309 Redirect the virtual parallel port to host device dev (same devices 4310 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4311 to use hardware devices connected on the corresponding host parallel 4312 port. 4313 4314 This option can be used several times to simulate up to 3 parallel 4315 ports. 4316 4317 Use ``-parallel none`` to disable all parallel ports. 4318ERST 4319 4320DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4321 "-monitor dev redirect the monitor to char device 'dev'\n", 4322 QEMU_ARCH_ALL) 4323SRST 4324``-monitor dev`` 4325 Redirect the monitor to host device dev (same devices as the serial 4326 port). The default device is ``vc`` in graphical mode and ``stdio`` 4327 in non graphical mode. Use ``-monitor none`` to disable the default 4328 monitor. 4329ERST 4330DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4331 "-qmp dev like -monitor but opens in 'control' mode\n", 4332 QEMU_ARCH_ALL) 4333SRST 4334``-qmp dev`` 4335 Like ``-monitor`` but opens in 'control' mode. For example, to make 4336 QMP available on localhost port 4444:: 4337 4338 -qmp tcp:localhost:4444,server=on,wait=off 4339 4340 Not all options are configurable via this syntax; for maximum 4341 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4342 4343ERST 4344DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4345 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4346 QEMU_ARCH_ALL) 4347SRST 4348``-qmp-pretty dev`` 4349 Like ``-qmp`` but uses pretty JSON formatting. 4350ERST 4351 4352DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4353 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4354SRST 4355``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4356 Set up a monitor connected to the chardev ``name``. 4357 QEMU supports two monitors: the Human Monitor Protocol 4358 (HMP; for human interaction), and the QEMU Monitor Protocol 4359 (QMP; a JSON RPC-style protocol). 4360 The default is HMP; ``mode=control`` selects QMP instead. 4361 ``pretty`` is only valid when ``mode=control``, 4362 turning on JSON pretty printing to ease 4363 human reading and debugging. 4364 4365 For example:: 4366 4367 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4368 -mon chardev=mon1,mode=control,pretty=on 4369 4370 enables the QMP monitor on localhost port 4444 with pretty-printing. 4371ERST 4372 4373DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4374 "-debugcon dev redirect the debug console to char device 'dev'\n", 4375 QEMU_ARCH_ALL) 4376SRST 4377``-debugcon dev`` 4378 Redirect the debug console to host device dev (same devices as the 4379 serial port). The debug console is an I/O port which is typically 4380 port 0xe9; writing to that I/O port sends output to this device. The 4381 default device is ``vc`` in graphical mode and ``stdio`` in non 4382 graphical mode. 4383ERST 4384 4385DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4386 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4387SRST 4388``-pidfile file`` 4389 Store the QEMU process PID in file. It is useful if you launch QEMU 4390 from a script. 4391ERST 4392 4393DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4394 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4395 QEMU_ARCH_ALL) 4396SRST 4397``--preconfig`` 4398 Pause QEMU for interactive configuration before the machine is 4399 created, which allows querying and configuring properties that will 4400 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4401 exit the preconfig state and move to the next state (i.e. run guest 4402 if -S isn't used or pause the second time if -S is used). This 4403 option is experimental. 4404ERST 4405 4406DEF("S", 0, QEMU_OPTION_S, \ 4407 "-S freeze CPU at startup (use 'c' to start execution)\n", 4408 QEMU_ARCH_ALL) 4409SRST 4410``-S`` 4411 Do not start CPU at startup (you must type 'c' in the monitor). 4412ERST 4413 4414DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4415 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4416 " run qemu with overcommit hints\n" 4417 " mem-lock=on|off controls memory lock support (default: off)\n" 4418 " cpu-pm=on|off controls cpu power management (default: off)\n", 4419 QEMU_ARCH_ALL) 4420SRST 4421``-overcommit mem-lock=on|off`` 4422 \ 4423``-overcommit cpu-pm=on|off`` 4424 Run qemu with hints about host resource overcommit. The default is 4425 to assume that host overcommits all resources. 4426 4427 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4428 (disabled by default). This works when host memory is not 4429 overcommitted and reduces the worst-case latency for guest. 4430 4431 Guest ability to manage power state of host cpus (increasing latency 4432 for other processes on the same host cpu, but decreasing latency for 4433 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4434 works best when host CPU is not overcommitted. When used, host 4435 estimates of CPU cycle and power utilization will be incorrect, not 4436 taking into account guest idle time. 4437ERST 4438 4439DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4440 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4441 " the guest without waiting for gdb to connect; use -S too\n" 4442 " if you want it to not start execution.)\n", 4443 QEMU_ARCH_ALL) 4444SRST 4445``-gdb dev`` 4446 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4447 in the System Emulation Users Guide). Note that this option does not pause QEMU 4448 execution -- if you want QEMU to not start the guest until you 4449 connect with gdb and issue a ``continue`` command, you will need to 4450 also pass the ``-S`` option to QEMU. 4451 4452 The most usual configuration is to listen on a local TCP socket:: 4453 4454 -gdb tcp::3117 4455 4456 but you can specify other backends; UDP, pseudo TTY, or even stdio 4457 are all reasonable use cases. For example, a stdio connection 4458 allows you to start QEMU from within gdb and establish the 4459 connection via a pipe: 4460 4461 .. parsed-literal:: 4462 4463 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4464ERST 4465 4466DEF("s", 0, QEMU_OPTION_s, \ 4467 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4468 QEMU_ARCH_ALL) 4469SRST 4470``-s`` 4471 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4472 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4473ERST 4474 4475DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4476 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4477 QEMU_ARCH_ALL) 4478SRST 4479``-d item1[,...]`` 4480 Enable logging of specified items. Use '-d help' for a list of log 4481 items. 4482ERST 4483 4484DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4485 "-D logfile output log to logfile (default stderr)\n", 4486 QEMU_ARCH_ALL) 4487SRST 4488``-D logfile`` 4489 Output log in logfile instead of to stderr 4490ERST 4491 4492DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4493 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4494 QEMU_ARCH_ALL) 4495SRST 4496``-dfilter range1[,...]`` 4497 Filter debug output to that relevant to a range of target addresses. 4498 The filter spec can be either start+size, start-size or start..end 4499 where start end and size are the addresses and sizes required. For 4500 example: 4501 4502 :: 4503 4504 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4505 4506 Will dump output for any code in the 0x1000 sized block starting at 4507 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4508 another 0x1000 sized block starting at 0xffffffc00005f000. 4509ERST 4510 4511DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4512 "-seed number seed the pseudo-random number generator\n", 4513 QEMU_ARCH_ALL) 4514SRST 4515``-seed number`` 4516 Force the guest to use a deterministic pseudo-random number 4517 generator, seeded with number. This does not affect crypto routines 4518 within the host. 4519ERST 4520 4521DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4522 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4523 QEMU_ARCH_ALL) 4524SRST 4525``-L path`` 4526 Set the directory for the BIOS, VGA BIOS and keymaps. 4527 4528 To list all the data directories, use ``-L help``. 4529ERST 4530 4531DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4532 "-enable-kvm enable KVM full virtualization support\n", 4533 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4534 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4535SRST 4536``-enable-kvm`` 4537 Enable KVM full virtualization support. This option is only 4538 available if KVM support is enabled when compiling. 4539ERST 4540 4541DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4542 "-xen-domid id specify xen guest domain id\n", 4543 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4544DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4545 "-xen-attach attach to existing xen domain\n" 4546 " libxl will use this when starting QEMU\n", 4547 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4548DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4549 "-xen-domid-restrict restrict set of available xen operations\n" 4550 " to specified domain id. (Does not affect\n" 4551 " xenpv machine type).\n", 4552 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4553SRST 4554``-xen-domid id`` 4555 Specify xen guest domain id (XEN only). 4556 4557``-xen-attach`` 4558 Attach to existing xen domain. libxl will use this when starting 4559 QEMU (XEN only). Restrict set of available xen operations to 4560 specified domain id (XEN only). 4561ERST 4562 4563DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4564 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4565SRST 4566``-no-reboot`` 4567 Exit instead of rebooting. 4568ERST 4569 4570DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4571 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4572SRST 4573``-no-shutdown`` 4574 Don't exit QEMU on guest shutdown, but instead only stop the 4575 emulation. This allows for instance switching to monitor to commit 4576 changes to the disk image. 4577ERST 4578 4579DEF("action", HAS_ARG, QEMU_OPTION_action, 4580 "-action reboot=reset|shutdown\n" 4581 " action when guest reboots [default=reset]\n" 4582 "-action shutdown=poweroff|pause\n" 4583 " action when guest shuts down [default=poweroff]\n" 4584 "-action panic=pause|shutdown|exit-failure|none\n" 4585 " action when guest panics [default=shutdown]\n" 4586 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4587 " action when watchdog fires [default=reset]\n", 4588 QEMU_ARCH_ALL) 4589SRST 4590``-action event=action`` 4591 The action parameter serves to modify QEMU's default behavior when 4592 certain guest events occur. It provides a generic method for specifying the 4593 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4594 parameters. 4595 4596 Examples: 4597 4598 ``-action panic=none`` 4599 ``-action reboot=shutdown,shutdown=pause`` 4600 ``-device i6300esb -action watchdog=pause`` 4601 4602ERST 4603 4604DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4605 "-loadvm [tag|id]\n" \ 4606 " start right away with a saved state (loadvm in monitor)\n", 4607 QEMU_ARCH_ALL) 4608SRST 4609``-loadvm file`` 4610 Start right away with a saved state (``loadvm`` in monitor) 4611ERST 4612 4613#ifndef _WIN32 4614DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4615 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4616#endif 4617SRST 4618``-daemonize`` 4619 Daemonize the QEMU process after initialization. QEMU will not 4620 detach from standard IO until it is ready to receive connections on 4621 any of its devices. This option is a useful way for external 4622 programs to launch QEMU without having to cope with initialization 4623 race conditions. 4624ERST 4625 4626DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4627 "-option-rom rom load a file, rom, into the option ROM space\n", 4628 QEMU_ARCH_ALL) 4629SRST 4630``-option-rom file`` 4631 Load the contents of file as an option ROM. This option is useful to 4632 load things like EtherBoot. 4633ERST 4634 4635DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4636 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4637 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4638 QEMU_ARCH_ALL) 4639 4640SRST 4641``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4642 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4643 the current UTC or local time, respectively. ``localtime`` is 4644 required for correct date in MS-DOS or Windows. To start at a 4645 specific point in time, provide datetime in the format 4646 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4647 4648 By default the RTC is driven by the host system time. This allows 4649 using of the RTC as accurate reference clock inside the guest, 4650 specifically if the host time is smoothly following an accurate 4651 external reference clock, e.g. via NTP. If you want to isolate the 4652 guest time from the host, you can set ``clock`` to ``rt`` instead, 4653 which provides a host monotonic clock if host support it. To even 4654 prevent the RTC from progressing during suspension, you can set 4655 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4656 recommended especially in icount mode in order to preserve 4657 determinism; however, note that in icount mode the speed of the 4658 virtual clock is variable and can in general differ from the host 4659 clock. 4660 4661 Enable ``driftfix`` (i386 targets only) if you experience time drift 4662 problems, specifically with Windows' ACPI HAL. This option will try 4663 to figure out how many timer interrupts were not processed by the 4664 Windows guest and will re-inject them. 4665ERST 4666 4667DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4668 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4669 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4670 " instruction, enable aligning the host and virtual clocks\n" \ 4671 " or disable real time cpu sleeping, and optionally enable\n" \ 4672 " record-and-replay mode\n", QEMU_ARCH_ALL) 4673SRST 4674``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4675 Enable virtual instruction counter. The virtual cpu will execute one 4676 instruction every 2^N ns of virtual time. If ``auto`` is specified 4677 then the virtual cpu speed will be automatically adjusted to keep 4678 virtual time within a few seconds of real time. 4679 4680 Note that while this option can give deterministic behavior, it does 4681 not provide cycle accurate emulation. Modern CPUs contain 4682 superscalar out of order cores with complex cache hierarchies. The 4683 number of instructions executed often has little or no correlation 4684 with actual performance. 4685 4686 When the virtual cpu is sleeping, the virtual time will advance at 4687 default speed unless ``sleep=on`` is specified. With 4688 ``sleep=on``, the virtual time will jump to the next timer 4689 deadline instantly whenever the virtual cpu goes to sleep mode and 4690 will not advance if no timer is enabled. This behavior gives 4691 deterministic execution times from the guest point of view. 4692 The default if icount is enabled is ``sleep=off``. 4693 ``sleep=on`` cannot be used together with either ``shift=auto`` 4694 or ``align=on``. 4695 4696 ``align=on`` will activate the delay algorithm which will try to 4697 synchronise the host clock and the virtual clock. The goal is to 4698 have a guest running at the real frequency imposed by the shift 4699 option. Whenever the guest clock is behind the host clock and if 4700 ``align=on`` is specified then we print a message to the user to 4701 inform about the delay. Currently this option does not work when 4702 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4703 shift values for which the guest clock runs ahead of the host clock. 4704 Typically this happens when the shift value is high (how high 4705 depends on the host machine). The default if icount is enabled 4706 is ``align=off``. 4707 4708 When the ``rr`` option is specified deterministic record/replay is 4709 enabled. The ``rrfile=`` option must also be provided to 4710 specify the path to the replay log. In record mode data is written 4711 to this file, and in replay mode it is read back. 4712 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4713 name. In record mode, a new VM snapshot with the given name is created 4714 at the start of execution recording. In replay mode this option 4715 specifies the snapshot name used to load the initial VM state. 4716ERST 4717 4718DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4719 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4720 " action when watchdog fires [default=reset]\n", 4721 QEMU_ARCH_ALL) 4722SRST 4723``-watchdog-action action`` 4724 The action controls what QEMU will do when the watchdog timer 4725 expires. The default is ``reset`` (forcefully reset the guest). 4726 Other possible actions are: ``shutdown`` (attempt to gracefully 4727 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4728 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4729 guest), ``debug`` (print a debug message and continue), or ``none`` 4730 (do nothing). 4731 4732 Note that the ``shutdown`` action requires that the guest responds 4733 to ACPI signals, which it may not be able to do in the sort of 4734 situations where the watchdog would have expired, and thus 4735 ``-watchdog-action shutdown`` is not recommended for production use. 4736 4737 Examples: 4738 4739 ``-device i6300esb -watchdog-action pause`` 4740 4741ERST 4742 4743DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4744 "-echr chr set terminal escape character instead of ctrl-a\n", 4745 QEMU_ARCH_ALL) 4746SRST 4747``-echr numeric_ascii_value`` 4748 Change the escape character used for switching to the monitor when 4749 using monitor and serial sharing. The default is ``0x01`` when using 4750 the ``-nographic`` option. ``0x01`` is equal to pressing 4751 ``Control-a``. You can select a different character from the ascii 4752 control keys where 1 through 26 map to Control-a through Control-z. 4753 For instance you could use the either of the following to change the 4754 escape character to Control-t. 4755 4756 ``-echr 0x14``; \ ``-echr 20`` 4757 4758ERST 4759 4760DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4761 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4762 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4763 "-incoming unix:socketpath\n" \ 4764 " prepare for incoming migration, listen on\n" \ 4765 " specified protocol and socket address\n" \ 4766 "-incoming fd:fd\n" \ 4767 "-incoming file:filename[,offset=offset]\n" \ 4768 "-incoming exec:cmdline\n" \ 4769 " accept incoming migration on given file descriptor\n" \ 4770 " or from given external command\n" \ 4771 "-incoming defer\n" \ 4772 " wait for the URI to be specified via migrate_incoming\n", 4773 QEMU_ARCH_ALL) 4774SRST 4775``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4776 \ 4777``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4778 Prepare for incoming migration, listen on a given tcp port. 4779 4780``-incoming unix:socketpath`` 4781 Prepare for incoming migration, listen on a given unix socket. 4782 4783``-incoming fd:fd`` 4784 Accept incoming migration from a given file descriptor. 4785 4786``-incoming file:filename[,offset=offset]`` 4787 Accept incoming migration from a given file starting at offset. 4788 offset allows the common size suffixes, or a 0x prefix, but not both. 4789 4790``-incoming exec:cmdline`` 4791 Accept incoming migration as an output from specified external 4792 command. 4793 4794``-incoming defer`` 4795 Wait for the URI to be specified via migrate\_incoming. The monitor 4796 can be used to change settings (such as migration parameters) prior 4797 to issuing the migrate\_incoming to allow the migration to begin. 4798ERST 4799 4800DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4801 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4802SRST 4803``-only-migratable`` 4804 Only allow migratable devices. Devices will not be allowed to enter 4805 an unmigratable state. 4806ERST 4807 4808DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4809 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4810SRST 4811``-nodefaults`` 4812 Don't create default devices. Normally, QEMU sets the default 4813 devices like serial port, parallel port, virtual console, monitor 4814 device, VGA adapter, floppy and CD-ROM drive and others. The 4815 ``-nodefaults`` option will disable all those default devices. 4816ERST 4817 4818#ifndef _WIN32 4819DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4820 "-runas user change to user id user just before starting the VM\n" \ 4821 " user can be numeric uid:gid instead\n", 4822 QEMU_ARCH_ALL) 4823#endif 4824SRST 4825``-runas user`` 4826 Immediately before starting guest execution, drop root privileges, 4827 switching to the specified user. 4828ERST 4829 4830DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4831 "-prom-env variable=value\n" 4832 " set OpenBIOS nvram variables\n", 4833 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4834SRST 4835``-prom-env variable=value`` 4836 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4837 4838 :: 4839 4840 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4841 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4842 4843 :: 4844 4845 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4846 -prom-env 'boot-device=hd:2,\yaboot' \ 4847 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4848ERST 4849DEF("semihosting", 0, QEMU_OPTION_semihosting, 4850 "-semihosting semihosting mode\n", 4851 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4852 QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 4853SRST 4854``-semihosting`` 4855 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, RISC-V only). 4856 4857 .. warning:: 4858 Note that this allows guest direct access to the host filesystem, so 4859 should only be used with a trusted guest OS. 4860 4861 See the -semihosting-config option documentation for further 4862 information about the facilities this enables. 4863ERST 4864DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4865 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4866 " semihosting configuration\n", 4867QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4868QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 4869SRST 4870``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4871 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, RISC-V 4872 only). 4873 4874 .. warning:: 4875 Note that this allows guest direct access to the host filesystem, so 4876 should only be used with a trusted guest OS. 4877 4878 ``target=native|gdb|auto`` 4879 Defines where the semihosting calls will be addressed, to QEMU 4880 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4881 means ``gdb`` during debug sessions and ``native`` otherwise. 4882 4883 ``chardev=str1`` 4884 Send the output to a chardev backend output for native or auto 4885 output when not in gdb 4886 4887 ``userspace=on|off`` 4888 Allows code running in guest userspace to access the semihosting 4889 interface. The default is that only privileged guest code can 4890 make semihosting calls. Note that setting ``userspace=on`` should 4891 only be used if all guest code is trusted (for example, in 4892 bare-metal test case code). 4893 4894 ``arg=str1,arg=str2,...`` 4895 Allows the user to pass input arguments, and can be used 4896 multiple times to build up a list. The old-style 4897 ``-kernel``/``-append`` method of passing a command line is 4898 still supported for backward compatibility. If both the 4899 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4900 specified, the former is passed to semihosting as it always 4901 takes precedence. 4902ERST 4903DEF("old-param", 0, QEMU_OPTION_old_param, 4904 "-old-param old param mode\n", QEMU_ARCH_ARM) 4905SRST 4906``-old-param`` 4907 Old param mode (ARM only). 4908ERST 4909 4910DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4911 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4912 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4913 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4914 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4915 " by the kernel, but typically no longer used by modern\n" \ 4916 " C library implementations.\n" \ 4917 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4918 " to elevate privileges using set*uid|gid system calls.\n" \ 4919 " The value 'children' will deny set*uid|gid system calls for\n" \ 4920 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4921 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4922 " blocking *fork and execve\n" \ 4923 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4924 QEMU_ARCH_ALL) 4925SRST 4926``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4927 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4928 filtering and 'off' will disable it. The default is 'off'. 4929 4930 ``obsolete=string`` 4931 Enable Obsolete system calls 4932 4933 ``elevateprivileges=string`` 4934 Disable set\*uid\|gid system calls 4935 4936 ``spawn=string`` 4937 Disable \*fork and execve 4938 4939 ``resourcecontrol=string`` 4940 Disable process affinity and schedular priority 4941ERST 4942 4943DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4944 "-readconfig <file>\n" 4945 " read config file\n", QEMU_ARCH_ALL) 4946SRST 4947``-readconfig file`` 4948 Read device configuration from file. This approach is useful when 4949 you want to spawn QEMU process with many command line options but 4950 you don't want to exceed the command line character limit. 4951ERST 4952 4953DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4954 "-no-user-config\n" 4955 " do not load default user-provided config files at startup\n", 4956 QEMU_ARCH_ALL) 4957SRST 4958``-no-user-config`` 4959 The ``-no-user-config`` option makes QEMU not load any of the 4960 user-provided config files on sysconfdir. 4961ERST 4962 4963DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4964 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4965 " specify tracing options\n", 4966 QEMU_ARCH_ALL) 4967SRST 4968``-trace [[enable=]pattern][,events=file][,file=file]`` 4969 .. include:: ../qemu-option-trace.rst.inc 4970 4971ERST 4972DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4973 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4974 " load a plugin\n", 4975 QEMU_ARCH_ALL) 4976SRST 4977``-plugin file=file[,argname=argvalue]`` 4978 Load a plugin. 4979 4980 ``file=file`` 4981 Load the given plugin from a shared library file. 4982 4983 ``argname=argvalue`` 4984 Argument passed to the plugin. (Can be given multiple times.) 4985ERST 4986 4987HXCOMM Internal use 4988DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4989DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4990 4991#ifdef CONFIG_POSIX 4992DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4993 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4994 " Set miscellaneous QEMU process lifecycle options:\n" 4995 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4996 " chroot=dir chroot to dir just before starting the VM\n", 4997 QEMU_ARCH_ALL) 4998SRST 4999``-run-with [async-teardown=on|off][,chroot=dir]`` 5000 Set QEMU process lifecycle options. 5001 5002 ``async-teardown=on`` enables asynchronous teardown. A new process called 5003 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5004 space with the main QEMU process, using clone. It will wait for the 5005 main QEMU process to terminate completely, and then exit. This allows 5006 QEMU to terminate very quickly even if the guest was huge, leaving the 5007 teardown of the address space to the cleanup process. Since the cleanup 5008 process shares the same cgroups as the main QEMU process, accounting is 5009 performed correctly. This only works if the cleanup process is not 5010 forcefully killed with SIGKILL before the main QEMU process has 5011 terminated completely. 5012 5013 ``chroot=dir`` can be used for doing a chroot to the specified directory 5014 immediately before starting the guest execution. This is especially useful 5015 in combination with -runas. 5016ERST 5017#endif 5018 5019DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5020 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5021 " control error message format\n" 5022 " timestamp=on enables timestamps (default: off)\n" 5023 " guest-name=on enables guest name prefix but only if\n" 5024 " -name guest option is set (default: off)\n", 5025 QEMU_ARCH_ALL) 5026SRST 5027``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5028 Control error message format. 5029 5030 ``timestamp=on|off`` 5031 Prefix messages with a timestamp. Default is off. 5032 5033 ``guest-name=on|off`` 5034 Prefix messages with guest name but only if -name guest option is set 5035 otherwise the option is ignored. Default is off. 5036ERST 5037 5038DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5039 "-dump-vmstate <file>\n" 5040 " Output vmstate information in JSON format to file.\n" 5041 " Use the scripts/vmstate-static-checker.py file to\n" 5042 " check for possible regressions in migration code\n" 5043 " by comparing two such vmstate dumps.\n", 5044 QEMU_ARCH_ALL) 5045SRST 5046``-dump-vmstate file`` 5047 Dump json-encoded vmstate information for current machine type to 5048 file in file 5049ERST 5050 5051DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5052 "-enable-sync-profile\n" 5053 " enable synchronization profiling\n", 5054 QEMU_ARCH_ALL) 5055SRST 5056``-enable-sync-profile`` 5057 Enable synchronization profiling. 5058ERST 5059 5060#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5061DEF("perfmap", 0, QEMU_OPTION_perfmap, 5062 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5063 QEMU_ARCH_ALL) 5064SRST 5065``-perfmap`` 5066 Generate a map file for Linux perf tools that will allow basic profiling 5067 information to be broken down into basic blocks. 5068ERST 5069 5070DEF("jitdump", 0, QEMU_OPTION_jitdump, 5071 "-jitdump generate a jit-${pid}.dump file for perf\n", 5072 QEMU_ARCH_ALL) 5073SRST 5074``-jitdump`` 5075 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5076 names, line numbers and JITted code. 5077ERST 5078#endif 5079 5080DEFHEADING() 5081 5082DEFHEADING(Generic object creation:) 5083 5084DEF("object", HAS_ARG, QEMU_OPTION_object, 5085 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5086 " create a new object of type TYPENAME setting properties\n" 5087 " in the order they are specified. Note that the 'id'\n" 5088 " property must be set. These objects are placed in the\n" 5089 " '/objects' path.\n", 5090 QEMU_ARCH_ALL) 5091SRST 5092``-object typename[,prop1=value1,...]`` 5093 Create a new object of type typename setting properties in the order 5094 they are specified. Note that the 'id' property must be set. These 5095 objects are placed in the '/objects' path. 5096 5097 ``-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`` 5098 Creates a memory file backend object, which can be used to back 5099 the guest RAM with huge pages. 5100 5101 The ``id`` parameter is a unique ID that will be used to 5102 reference this memory region in other parameters, e.g. ``-numa``, 5103 ``-device nvdimm``, etc. 5104 5105 The ``size`` option provides the size of the memory region, and 5106 accepts common suffixes, e.g. ``500M``. 5107 5108 The ``mem-path`` provides the path to either a shared memory or 5109 huge page filesystem mount. 5110 5111 The ``share`` boolean option determines whether the memory 5112 region is marked as private to QEMU, or shared. The latter 5113 allows a co-operating external process to access the QEMU memory 5114 region. 5115 5116 Setting share=on might affect the ability to configure NUMA 5117 bindings for the memory backend under some circumstances, see 5118 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5119 source tree for additional details. 5120 5121 Setting the ``discard-data`` boolean option to on indicates that 5122 file contents can be destroyed when QEMU exits, to avoid 5123 unnecessarily flushing data to the backing file. Note that 5124 ``discard-data`` is only an optimization, and QEMU might not 5125 discard file contents if it aborts unexpectedly or is terminated 5126 using SIGKILL. 5127 5128 The ``merge`` boolean option enables memory merge, also known as 5129 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5130 the pages for memory deduplication. 5131 5132 Setting the ``dump`` boolean option to off excludes the memory 5133 from core dumps. This feature is also known as MADV\_DONTDUMP. 5134 5135 The ``prealloc`` boolean option enables memory preallocation. 5136 5137 The ``host-nodes`` option binds the memory range to a list of 5138 NUMA host nodes. 5139 5140 The ``policy`` option sets the NUMA policy to one of the 5141 following values: 5142 5143 ``default`` 5144 default host policy 5145 5146 ``preferred`` 5147 prefer the given host node list for allocation 5148 5149 ``bind`` 5150 restrict memory allocation to the given host node list 5151 5152 ``interleave`` 5153 interleave memory allocations across the given host node 5154 list 5155 5156 The ``align`` option specifies the base address alignment when 5157 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5158 ``2M``. Some backend store specified by ``mem-path`` requires an 5159 alignment different than the default one used by QEMU, eg the 5160 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5161 such cases, users can specify the required alignment via this 5162 option. 5163 5164 The ``offset`` option specifies the offset into the target file 5165 that the region starts at. You can use this parameter to back 5166 multiple regions with a single file. 5167 5168 The ``pmem`` option specifies whether the backing file specified 5169 by ``mem-path`` is in host persistent memory that can be 5170 accessed using the SNIA NVM programming model (e.g. Intel 5171 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5172 operations to guarantee the persistence of its own writes to 5173 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5174 migration). Also, we will map the backend-file with MAP\_SYNC 5175 flag, which ensures the file metadata is in sync for 5176 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5177 requires support from both the host kernel (since Linux kernel 5178 4.15) and the filesystem of ``mem-path`` mounted with DAX 5179 option. 5180 5181 The ``readonly`` option specifies whether the backing file is opened 5182 read-only or read-write (default). 5183 5184 The ``rom`` option specifies whether to create Read Only Memory 5185 (ROM) that cannot be modified by the VM. Any write attempts to such 5186 ROM will be denied. Most use cases want proper RAM instead of ROM. 5187 However, selected use cases, like R/O NVDIMMs, can benefit from 5188 ROM. If set to ``on``, create ROM; if set to ``off``, create 5189 writable RAM; if set to ``auto`` (default), the value of the 5190 ``readonly`` option is used. This option is primarily helpful when 5191 we want to have writable RAM in configurations that would 5192 traditionally create ROM before the ``rom`` option was introduced: 5193 VM templating, where we want to open a file readonly 5194 (``readonly=on``) and mark the memory to be private for QEMU 5195 (``share=off``). For this use case, we need writable RAM instead 5196 of ROM, and want to also set ``rom=off``. 5197 5198 ``-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`` 5199 Creates a memory backend object, which can be used to back the 5200 guest RAM. Memory backend objects offer more control than the 5201 ``-m`` option that is traditionally used to define guest RAM. 5202 Please refer to ``memory-backend-file`` for a description of the 5203 options. 5204 5205 ``-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`` 5206 Creates an anonymous memory file backend object, which allows 5207 QEMU to share the memory with an external process (e.g. when 5208 using vhost-user). The memory is allocated with memfd and 5209 optional sealing. (Linux only) 5210 5211 The ``seal`` option creates a sealed-file, that will block 5212 further resizing the memory ('on' by default). 5213 5214 The ``hugetlb`` option specify the file to be created resides in 5215 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5216 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5217 the hugetlb page size on systems that support multiple hugetlb 5218 page sizes (it must be a power of 2 value supported by the 5219 system). 5220 5221 In some versions of Linux, the ``hugetlb`` option is 5222 incompatible with the ``seal`` option (requires at least Linux 5223 4.16). 5224 5225 Please refer to ``memory-backend-file`` for a description of the 5226 other options. 5227 5228 The ``share`` boolean option is on by default with memfd. 5229 5230 ``-object iommufd,id=id[,fd=fd]`` 5231 Creates an iommufd backend which allows control of DMA mapping 5232 through the ``/dev/iommu`` device. 5233 5234 The ``id`` parameter is a unique ID which frontends (such as 5235 vfio-pci of vdpa) will use to connect with the iommufd backend. 5236 5237 The ``fd`` parameter is an optional pre-opened file descriptor 5238 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5239 across all subsystems, bringing the benefit of centralized 5240 reference counting. 5241 5242 ``-object rng-builtin,id=id`` 5243 Creates a random number generator backend which obtains entropy 5244 from QEMU builtin functions. The ``id`` parameter is a unique ID 5245 that will be used to reference this entropy backend from the 5246 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5247 uses this RNG backend. 5248 5249 ``-object rng-random,id=id,filename=/dev/random`` 5250 Creates a random number generator backend which obtains entropy 5251 from a device on the host. The ``id`` parameter is a unique ID 5252 that will be used to reference this entropy backend from the 5253 ``virtio-rng`` device. The ``filename`` parameter specifies 5254 which file to obtain entropy from and if omitted defaults to 5255 ``/dev/urandom``. 5256 5257 ``-object rng-egd,id=id,chardev=chardevid`` 5258 Creates a random number generator backend which obtains entropy 5259 from an external daemon running on the host. The ``id`` 5260 parameter is a unique ID that will be used to reference this 5261 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5262 parameter is the unique ID of a character device backend that 5263 provides the connection to the RNG daemon. 5264 5265 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5266 Creates a TLS anonymous credentials object, which can be used to 5267 provide TLS support on network backends. The ``id`` parameter is 5268 a unique ID which network backends will use to access the 5269 credentials. The ``endpoint`` is either ``server`` or ``client`` 5270 depending on whether the QEMU network backend that uses the 5271 credentials will be acting as a client or as a server. If 5272 ``verify-peer`` is enabled (the default) then once the handshake 5273 is completed, the peer credentials will be verified, though this 5274 is a no-op for anonymous credentials. 5275 5276 The dir parameter tells QEMU where to find the credential files. 5277 For server endpoints, this directory may contain a file 5278 dh-params.pem providing diffie-hellman parameters to use for the 5279 TLS server. If the file is missing, QEMU will generate a set of 5280 DH parameters at startup. This is a computationally expensive 5281 operation that consumes random pool entropy, so it is 5282 recommended that a persistent set of parameters be generated 5283 upfront and saved. 5284 5285 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5286 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5287 can be used to provide TLS support on network backends. The 5288 ``id`` parameter is a unique ID which network backends will use 5289 to access the credentials. The ``endpoint`` is either ``server`` 5290 or ``client`` depending on whether the QEMU network backend that 5291 uses the credentials will be acting as a client or as a server. 5292 For clients only, ``username`` is the username which will be 5293 sent to the server. If omitted it defaults to "qemu". 5294 5295 The dir parameter tells QEMU where to find the keys file. It is 5296 called "dir/keys.psk" and contains "username:key" pairs. This 5297 file can most easily be created using the GnuTLS ``psktool`` 5298 program. 5299 5300 For server endpoints, dir may also contain a file dh-params.pem 5301 providing diffie-hellman parameters to use for the TLS server. 5302 If the file is missing, QEMU will generate a set of DH 5303 parameters at startup. This is a computationally expensive 5304 operation that consumes random pool entropy, so it is 5305 recommended that a persistent set of parameters be generated up 5306 front and saved. 5307 5308 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5309 Creates a TLS anonymous credentials object, which can be used to 5310 provide TLS support on network backends. The ``id`` parameter is 5311 a unique ID which network backends will use to access the 5312 credentials. The ``endpoint`` is either ``server`` or ``client`` 5313 depending on whether the QEMU network backend that uses the 5314 credentials will be acting as a client or as a server. If 5315 ``verify-peer`` is enabled (the default) then once the handshake 5316 is completed, the peer credentials will be verified. With x509 5317 certificates, this implies that the clients must be provided 5318 with valid client certificates too. 5319 5320 The dir parameter tells QEMU where to find the credential files. 5321 For server endpoints, this directory may contain a file 5322 dh-params.pem providing diffie-hellman parameters to use for the 5323 TLS server. If the file is missing, QEMU will generate a set of 5324 DH parameters at startup. This is a computationally expensive 5325 operation that consumes random pool entropy, so it is 5326 recommended that a persistent set of parameters be generated 5327 upfront and saved. 5328 5329 For x509 certificate credentials the directory will contain 5330 further files providing the x509 certificates. The certificates 5331 must be stored in PEM format, in filenames ca-cert.pem, 5332 ca-crl.pem (optional), server-cert.pem (only servers), 5333 server-key.pem (only servers), client-cert.pem (only clients), 5334 and client-key.pem (only clients). 5335 5336 For the server-key.pem and client-key.pem files which contain 5337 sensitive private keys, it is possible to use an encrypted 5338 version by providing the passwordid parameter. This provides the 5339 ID of a previously created ``secret`` object containing the 5340 password for decryption. 5341 5342 The priority parameter allows to override the global default 5343 priority used by gnutls. This can be useful if the system 5344 administrator needs to use a weaker set of crypto priorities for 5345 QEMU without potentially forcing the weakness onto all 5346 applications. Or conversely if one wants wants a stronger 5347 default for QEMU than for all other applications, they can do 5348 this through this parameter. Its format is a gnutls priority 5349 string as described at 5350 https://gnutls.org/manual/html_node/Priority-Strings.html. 5351 5352 ``-object tls-cipher-suites,id=id,priority=priority`` 5353 Creates a TLS cipher suites object, which can be used to control 5354 the TLS cipher/protocol algorithms that applications are permitted 5355 to use. 5356 5357 The ``id`` parameter is a unique ID which frontends will use to 5358 access the ordered list of permitted TLS cipher suites from the 5359 host. 5360 5361 The ``priority`` parameter allows to override the global default 5362 priority used by gnutls. This can be useful if the system 5363 administrator needs to use a weaker set of crypto priorities for 5364 QEMU without potentially forcing the weakness onto all 5365 applications. Or conversely if one wants wants a stronger 5366 default for QEMU than for all other applications, they can do 5367 this through this parameter. Its format is a gnutls priority 5368 string as described at 5369 https://gnutls.org/manual/html_node/Priority-Strings.html. 5370 5371 An example of use of this object is to control UEFI HTTPS Boot. 5372 The tls-cipher-suites object exposes the ordered list of permitted 5373 TLS cipher suites from the host side to the guest firmware, via 5374 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5375 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5376 guest-side TLS. 5377 5378 In the following example, the priority at which the host-side policy 5379 is retrieved is given by the ``priority`` property. 5380 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5381 refer to /etc/crypto-policies/back-ends/gnutls.config. 5382 5383 .. parsed-literal:: 5384 5385 # |qemu_system| \\ 5386 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5387 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5388 5389 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5390 Interval t can't be 0, this filter batches the packet delivery: 5391 all packets arriving in a given interval on netdev netdevid are 5392 delayed until the end of the interval. Interval is in 5393 microseconds. ``status`` is optional that indicate whether the 5394 netfilter is on (enabled) or off (disabled), the default status 5395 for netfilter will be 'on'. 5396 5397 queue all\|rx\|tx is an option that can be applied to any 5398 netfilter. 5399 5400 ``all``: the filter is attached both to the receive and the 5401 transmit queue of the netdev (default). 5402 5403 ``rx``: the filter is attached to the receive queue of the 5404 netdev, where it will receive packets sent to the netdev. 5405 5406 ``tx``: the filter is attached to the transmit queue of the 5407 netdev, where it will receive packets sent by the netdev. 5408 5409 position head\|tail\|id=<id> is an option to specify where the 5410 filter should be inserted in the filter list. It can be applied 5411 to any netfilter. 5412 5413 ``head``: the filter is inserted at the head of the filter list, 5414 before any existing filters. 5415 5416 ``tail``: the filter is inserted at the tail of the filter list, 5417 behind any existing filters (default). 5418 5419 ``id=<id>``: the filter is inserted before or behind the filter 5420 specified by <id>, see the insert option below. 5421 5422 insert behind\|before is an option to specify where to insert 5423 the new filter relative to the one specified with 5424 position=id=<id>. It can be applied to any netfilter. 5425 5426 ``before``: insert before the specified filter. 5427 5428 ``behind``: insert behind the specified filter (default). 5429 5430 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5431 filter-mirror on netdev netdevid,mirror net packet to 5432 chardevchardevid, if it has the vnet\_hdr\_support flag, 5433 filter-mirror will mirror packet with vnet\_hdr\_len. 5434 5435 ``-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]`` 5436 filter-redirector on netdev netdevid,redirect filter's net 5437 packet to chardev chardevid,and redirect indev's packet to 5438 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5439 will redirect packet with vnet\_hdr\_len. Create a 5440 filter-redirector we need to differ outdev id from indev id, id 5441 can not be the same. we can just use indev or outdev, but at 5442 least one of indev or outdev need to be specified. 5443 5444 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5445 Filter-rewriter is a part of COLO project.It will rewrite tcp 5446 packet to secondary from primary to keep secondary tcp 5447 connection,and rewrite tcp packet to primary from secondary make 5448 tcp packet can be handled by client.if it has the 5449 vnet\_hdr\_support flag, we can parse packet with vnet header. 5450 5451 usage: colo secondary: -object 5452 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5453 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5454 filter-rewriter,id=rew0,netdev=hn0,queue=all 5455 5456 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5457 Dump the network traffic on netdev dev to the file specified by 5458 filename. At most len bytes (64k by default) per packet are 5459 stored. The file format is libpcap, so it can be analyzed with 5460 tools such as tcpdump or Wireshark. 5461 5462 ``-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}]`` 5463 Colo-compare gets packet from primary\_in chardevid and 5464 secondary\_in, then compare whether the payload of primary packet 5465 and secondary packet are the same. If same, it will output 5466 primary packet to out\_dev, else it will notify COLO-framework to do 5467 checkpoint and send primary packet to out\_dev. In order to 5468 improve efficiency, we need to put the task of comparison in 5469 another iothread. If it has the vnet\_hdr\_support flag, 5470 colo compare will send/recv packet with vnet\_hdr\_len. 5471 The compare\_timeout=@var{ms} determines the maximum time of the 5472 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5473 is to set the period of scanning expired primary node network packets. 5474 The max\_queue\_size=@var{size} is to set the max compare queue 5475 size depend on user environment. 5476 If user want to use Xen COLO, need to add the notify\_dev to 5477 notify Xen colo-frame to do checkpoint. 5478 5479 COLO-compare must be used with the help of filter-mirror, 5480 filter-redirector and filter-rewriter. 5481 5482 :: 5483 5484 KVM COLO 5485 5486 primary: 5487 -netdev tap,id=hn0,vhost=off 5488 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5489 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5490 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5491 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5492 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5493 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5494 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5495 -object iothread,id=iothread1 5496 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5497 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5498 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5499 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5500 5501 secondary: 5502 -netdev tap,id=hn0,vhost=off 5503 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5504 -chardev socket,id=red0,host=3.3.3.3,port=9003 5505 -chardev socket,id=red1,host=3.3.3.3,port=9004 5506 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5507 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5508 5509 5510 Xen COLO 5511 5512 primary: 5513 -netdev tap,id=hn0,vhost=off 5514 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5515 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5516 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5517 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5518 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5519 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5520 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5521 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5522 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5523 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5524 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5525 -object iothread,id=iothread1 5526 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5527 5528 secondary: 5529 -netdev tap,id=hn0,vhost=off 5530 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5531 -chardev socket,id=red0,host=3.3.3.3,port=9003 5532 -chardev socket,id=red1,host=3.3.3.3,port=9004 5533 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5534 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5535 5536 If you want to know the detail of above command line, you can 5537 read the colo-compare git log. 5538 5539 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5540 Creates a cryptodev backend which executes crypto operations from 5541 the QEMU cipher APIs. The id parameter is a unique ID that will 5542 be used to reference this cryptodev backend from the 5543 ``virtio-crypto`` device. The queues parameter is optional, 5544 which specify the queue number of cryptodev backend, the default 5545 of queues is 1. 5546 5547 .. parsed-literal:: 5548 5549 # |qemu_system| \\ 5550 [...] \\ 5551 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5552 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5553 [...] 5554 5555 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5556 Creates a vhost-user cryptodev backend, backed by a chardev 5557 chardevid. The id parameter is a unique ID that will be used to 5558 reference this cryptodev backend from the ``virtio-crypto`` 5559 device. The chardev should be a unix domain socket backed one. 5560 The vhost-user uses a specifically defined protocol to pass 5561 vhost ioctl replacement messages to an application on the other 5562 end of the socket. The queues parameter is optional, which 5563 specify the queue number of cryptodev backend for multiqueue 5564 vhost-user, the default of queues is 1. 5565 5566 .. parsed-literal:: 5567 5568 # |qemu_system| \\ 5569 [...] \\ 5570 -chardev socket,id=chardev0,path=/path/to/socket \\ 5571 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5572 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5573 [...] 5574 5575 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5576 \ 5577 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5578 Defines a secret to store a password, encryption key, or some 5579 other sensitive data. The sensitive data can either be passed 5580 directly via the data parameter, or indirectly via the file 5581 parameter. Using the data parameter is insecure unless the 5582 sensitive data is encrypted. 5583 5584 The sensitive data can be provided in raw format (the default), 5585 or base64. When encoded as JSON, the raw format only supports 5586 valid UTF-8 characters, so base64 is recommended for sending 5587 binary data. QEMU will convert from which ever format is 5588 provided to the format it needs internally. eg, an RBD password 5589 can be provided in raw format, even though it will be base64 5590 encoded when passed onto the RBD sever. 5591 5592 For added protection, it is possible to encrypt the data 5593 associated with a secret using the AES-256-CBC cipher. Use of 5594 encryption is indicated by providing the keyid and iv 5595 parameters. The keyid parameter provides the ID of a previously 5596 defined secret that contains the AES-256 decryption key. This 5597 key should be 32-bytes long and be base64 encoded. The iv 5598 parameter provides the random initialization vector used for 5599 encryption of this particular secret and should be a base64 5600 encrypted string of the 16-byte IV. 5601 5602 The simplest (insecure) usage is to provide the secret inline 5603 5604 .. parsed-literal:: 5605 5606 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5607 5608 The simplest secure usage is to provide the secret via a file 5609 5610 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5611 secret,id=sec0,file=mypasswd.txt,format=raw 5612 5613 For greater security, AES-256-CBC should be used. To illustrate 5614 usage, consider the openssl command line tool which can encrypt 5615 the data. Note that when encrypting, the plaintext must be 5616 padded to the cipher block size (32 bytes) using the standard 5617 PKCS#5/6 compatible padding algorithm. 5618 5619 First a master key needs to be created in base64 encoding: 5620 5621 :: 5622 5623 # openssl rand -base64 32 > key.b64 5624 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5625 5626 Each secret to be encrypted needs to have a random 5627 initialization vector generated. These do not need to be kept 5628 secret 5629 5630 :: 5631 5632 # openssl rand -base64 16 > iv.b64 5633 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5634 5635 The secret to be defined can now be encrypted, in this case 5636 we're telling openssl to base64 encode the result, but it could 5637 be left as raw bytes if desired. 5638 5639 :: 5640 5641 # SECRET=$(printf "letmein" | 5642 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5643 5644 When launching QEMU, create a master secret pointing to 5645 ``key.b64`` and specify that to be used to decrypt the user 5646 password. Pass the contents of ``iv.b64`` to the second secret 5647 5648 .. parsed-literal:: 5649 5650 # |qemu_system| \\ 5651 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5652 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5653 data=$SECRET,iv=$(<iv.b64) 5654 5655 ``-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]`` 5656 Create a Secure Encrypted Virtualization (SEV) guest object, 5657 which can be used to provide the guest memory encryption support 5658 on AMD processors. 5659 5660 When memory encryption is enabled, one of the physical address 5661 bit (aka the C-bit) is utilized to mark if a memory page is 5662 protected. The ``cbitpos`` is used to provide the C-bit 5663 position. The C-bit position is Host family dependent hence user 5664 must provide this value. On EPYC, the value should be 47. 5665 5666 When memory encryption is enabled, we loose certain bits in 5667 physical address space. The ``reduced-phys-bits`` is used to 5668 provide the number of bits we loose in physical address space. 5669 Similar to C-bit, the value is Host family dependent. On EPYC, 5670 a guest will lose a maximum of 1 bit, so the value should be 1. 5671 5672 The ``sev-device`` provides the device file to use for 5673 communicating with the SEV firmware running inside AMD Secure 5674 Processor. The default device is '/dev/sev'. If hardware 5675 supports memory encryption then /dev/sev devices are created by 5676 CCP driver. 5677 5678 The ``policy`` provides the guest policy to be enforced by the 5679 SEV firmware and restrict what configuration and operational 5680 commands can be performed on this guest by the hypervisor. The 5681 policy should be provided by the guest owner and is bound to the 5682 guest and cannot be changed throughout the lifetime of the 5683 guest. The default is 0. 5684 5685 If guest ``policy`` allows sharing the key with another SEV 5686 guest then ``handle`` can be use to provide handle of the guest 5687 from which to share the key. 5688 5689 The ``dh-cert-file`` and ``session-file`` provides the guest 5690 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5691 and session parameters are used for establishing a cryptographic 5692 session with the guest owner to negotiate keys used for 5693 attestation. The file must be encoded in base64. 5694 5695 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5696 cmdline to a designated guest firmware page for measured Linux 5697 boot with -kernel. The default is off. (Since 6.2) 5698 5699 e.g to launch a SEV guest 5700 5701 .. parsed-literal:: 5702 5703 # |qemu_system_x86| \\ 5704 ...... \\ 5705 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5706 -machine ...,memory-encryption=sev0 \\ 5707 ..... 5708 5709 ``-object authz-simple,id=id,identity=string`` 5710 Create an authorization object that will control access to 5711 network services. 5712 5713 The ``identity`` parameter is identifies the user and its format 5714 depends on the network service that authorization object is 5715 associated with. For authorizing based on TLS x509 certificates, 5716 the identity must be the x509 distinguished name. Note that care 5717 must be taken to escape any commas in the distinguished name. 5718 5719 An example authorization object to validate a x509 distinguished 5720 name would look like: 5721 5722 .. parsed-literal:: 5723 5724 # |qemu_system| \\ 5725 ... \\ 5726 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5727 ... 5728 5729 Note the use of quotes due to the x509 distinguished name 5730 containing whitespace, and escaping of ','. 5731 5732 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5733 Create an authorization object that will control access to 5734 network services. 5735 5736 The ``filename`` parameter is the fully qualified path to a file 5737 containing the access control list rules in JSON format. 5738 5739 An example set of rules that match against SASL usernames might 5740 look like: 5741 5742 :: 5743 5744 { 5745 "rules": [ 5746 { "match": "fred", "policy": "allow", "format": "exact" }, 5747 { "match": "bob", "policy": "allow", "format": "exact" }, 5748 { "match": "danb", "policy": "deny", "format": "glob" }, 5749 { "match": "dan*", "policy": "allow", "format": "exact" }, 5750 ], 5751 "policy": "deny" 5752 } 5753 5754 When checking access the object will iterate over all the rules 5755 and the first rule to match will have its ``policy`` value 5756 returned as the result. If no rules match, then the default 5757 ``policy`` value is returned. 5758 5759 The rules can either be an exact string match, or they can use 5760 the simple UNIX glob pattern matching to allow wildcards to be 5761 used. 5762 5763 If ``refresh`` is set to true the file will be monitored and 5764 automatically reloaded whenever its content changes. 5765 5766 As with the ``authz-simple`` object, the format of the identity 5767 strings being matched depends on the network service, but is 5768 usually a TLS x509 distinguished name, or a SASL username. 5769 5770 An example authorization object to validate a SASL username 5771 would look like: 5772 5773 .. parsed-literal:: 5774 5775 # |qemu_system| \\ 5776 ... \\ 5777 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5778 ... 5779 5780 ``-object authz-pam,id=id,service=string`` 5781 Create an authorization object that will control access to 5782 network services. 5783 5784 The ``service`` parameter provides the name of a PAM service to 5785 use for authorization. It requires that a file 5786 ``/etc/pam.d/service`` exist to provide the configuration for 5787 the ``account`` subsystem. 5788 5789 An example authorization object to validate a TLS x509 5790 distinguished name would look like: 5791 5792 .. parsed-literal:: 5793 5794 # |qemu_system| \\ 5795 ... \\ 5796 -object authz-pam,id=auth0,service=qemu-vnc \\ 5797 ... 5798 5799 There would then be a corresponding config file for PAM at 5800 ``/etc/pam.d/qemu-vnc`` that contains: 5801 5802 :: 5803 5804 account requisite pam_listfile.so item=user sense=allow \ 5805 file=/etc/qemu/vnc.allow 5806 5807 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5808 of x509 distinguished names that are permitted access 5809 5810 :: 5811 5812 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5813 5814 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5815 Creates a dedicated event loop thread that devices can be 5816 assigned to. This is known as an IOThread. By default device 5817 emulation happens in vCPU threads or the main event loop thread. 5818 This can become a scalability bottleneck. IOThreads allow device 5819 emulation and I/O to run on other host CPUs. 5820 5821 The ``id`` parameter is a unique ID that will be used to 5822 reference this IOThread from ``-device ...,iothread=id``. 5823 Multiple devices can be assigned to an IOThread. Note that not 5824 all devices support an ``iothread`` parameter. 5825 5826 The ``query-iothreads`` QMP command lists IOThreads and reports 5827 their thread IDs so that the user can configure host CPU 5828 pinning/affinity. 5829 5830 IOThreads use an adaptive polling algorithm to reduce event loop 5831 latency. Instead of entering a blocking system call to monitor 5832 file descriptors and then pay the cost of being woken up when an 5833 event occurs, the polling algorithm spins waiting for events for 5834 a short time. The algorithm's default parameters are suitable 5835 for many cases but can be adjusted based on knowledge of the 5836 workload and/or host device latency. 5837 5838 The ``poll-max-ns`` parameter is the maximum number of 5839 nanoseconds to busy wait for events. Polling can be disabled by 5840 setting this value to 0. 5841 5842 The ``poll-grow`` parameter is the multiplier used to increase 5843 the polling time when the algorithm detects it is missing events 5844 due to not polling long enough. 5845 5846 The ``poll-shrink`` parameter is the divisor used to decrease 5847 the polling time when the algorithm detects it is spending too 5848 long polling without encountering events. 5849 5850 The ``aio-max-batch`` parameter is the maximum number of requests 5851 in a batch for the AIO engine, 0 means that the engine will use 5852 its default. 5853 5854 The IOThread parameters can be modified at run-time using the 5855 ``qom-set`` command (where ``iothread1`` is the IOThread's 5856 ``id``): 5857 5858 :: 5859 5860 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5861ERST 5862 5863 5864HXCOMM This is the last statement. Insert new options before this line! 5865 5866#undef DEF 5867#undef DEFHEADING 5868#undef ARCHHEADING 5869
