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 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 155 4096KiB, 8192KiB and 16384KiB 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=512k 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 1175ERST 1176 1177DEF("name", HAS_ARG, QEMU_OPTION_name, 1178 "-name string1[,process=string2][,debug-threads=on|off]\n" 1179 " set the name of the guest\n" 1180 " string1 sets the window title and string2 the process name\n" 1181 " When debug-threads is enabled, individual threads are given a separate name\n" 1182 " NOTE: The thread names are for debugging and not a stable API.\n", 1183 QEMU_ARCH_ALL) 1184SRST 1185``-name name`` 1186 Sets the name of the guest. This name will be displayed in the SDL 1187 window caption. The name will also be used for the VNC server. Also 1188 optionally set the top visible process name in Linux. Naming of 1189 individual threads can also be enabled on Linux to aid debugging. 1190ERST 1191 1192DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1193 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1194 " specify machine UUID\n", QEMU_ARCH_ALL) 1195SRST 1196``-uuid uuid`` 1197 Set system UUID. 1198ERST 1199 1200DEFHEADING() 1201 1202DEFHEADING(Block device options:) 1203 1204SRST 1205The QEMU block device handling options have a long history and 1206have gone through several iterations as the feature set and complexity 1207of the block layer have grown. Many online guides to QEMU often 1208reference older and deprecated options, which can lead to confusion. 1209 1210The most explicit way to describe disks is to use a combination of 1211``-device`` to specify the hardware device and ``-blockdev`` to 1212describe the backend. The device defines what the guest sees and the 1213backend describes how QEMU handles the data. It is the only guaranteed 1214stable interface for describing block devices and as such is 1215recommended for management tools and scripting. 1216 1217The ``-drive`` option combines the device and backend into a single 1218command line option which is a more human friendly. There is however no 1219interface stability guarantee although some older board models still 1220need updating to work with the modern blockdev forms. 1221 1222Older options like ``-hda`` are essentially macros which expand into 1223``-drive`` options for various drive interfaces. The original forms 1224bake in a lot of assumptions from the days when QEMU was emulating a 1225legacy PC, they are not recommended for modern configurations. 1226 1227ERST 1228 1229DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1230 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1231DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1232SRST 1233``-fda file`` 1234 \ 1235``-fdb file`` 1236 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1237 the System Emulation Users Guide). 1238ERST 1239 1240DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1241 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1242DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1243DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1244 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1245DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1246SRST 1247``-hda file`` 1248 \ 1249``-hdb file`` 1250 \ 1251``-hdc file`` 1252 \ 1253``-hdd file`` 1254 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1255 emulated machine (this is for example the IDE bus on most x86 machines, 1256 but it can also be SCSI, virtio or something else on other target 1257 architectures). See also the :ref:`disk images` chapter in the System 1258 Emulation Users Guide. 1259ERST 1260 1261DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1262 "-cdrom file use 'file' as CD-ROM image\n", 1263 QEMU_ARCH_ALL) 1264SRST 1265``-cdrom file`` 1266 Use file as CD-ROM image on the default bus of the emulated machine 1267 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1268 at the same time there). On systems that support it, you can use the 1269 host CD-ROM by using ``/dev/cdrom`` as filename. 1270ERST 1271 1272DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1273 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1274 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1275 " [,read-only=on|off][,auto-read-only=on|off]\n" 1276 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1277 " [,driver specific parameters...]\n" 1278 " configure a block backend\n", QEMU_ARCH_ALL) 1279SRST 1280``-blockdev option[,option[,option[,...]]]`` 1281 Define a new block driver node. Some of the options apply to all 1282 block drivers, other options are only accepted for a specific block 1283 driver. See below for a list of generic options and options for the 1284 most common block drivers. 1285 1286 Options that expect a reference to another node (e.g. ``file``) can 1287 be given in two ways. Either you specify the node name of an already 1288 existing node (file=node-name), or you define a new node inline, 1289 adding options for the referenced node after a dot 1290 (file.filename=path,file.aio=native). 1291 1292 A block driver node created with ``-blockdev`` can be used for a 1293 guest device by specifying its node name for the ``drive`` property 1294 in a ``-device`` argument that defines a block device. 1295 1296 ``Valid options for any block driver node:`` 1297 ``driver`` 1298 Specifies the block driver to use for the given node. 1299 1300 ``node-name`` 1301 This defines the name of the block driver node by which it 1302 will be referenced later. The name must be unique, i.e. it 1303 must not match the name of a different block driver node, or 1304 (if you use ``-drive`` as well) the ID of a drive. 1305 1306 If no node name is specified, it is automatically generated. 1307 The generated node name is not intended to be predictable 1308 and changes between QEMU invocations. For the top level, an 1309 explicit node name must be specified. 1310 1311 ``read-only`` 1312 Open the node read-only. Guest write attempts will fail. 1313 1314 Note that some block drivers support only read-only access, 1315 either generally or in certain configurations. In this case, 1316 the default value ``read-only=off`` does not work and the 1317 option must be specified explicitly. 1318 1319 ``auto-read-only`` 1320 If ``auto-read-only=on`` is set, QEMU may fall back to 1321 read-only usage even when ``read-only=off`` is requested, or 1322 even switch between modes as needed, e.g. depending on 1323 whether the image file is writable or whether a writing user 1324 is attached to the node. 1325 1326 ``force-share`` 1327 Override the image locking system of QEMU by forcing the 1328 node to utilize weaker shared access for permissions where 1329 it would normally request exclusive access. When there is 1330 the potential for multiple instances to have the same file 1331 open (whether this invocation of QEMU is the first or the 1332 second instance), both instances must permit shared access 1333 for the second instance to succeed at opening the file. 1334 1335 Enabling ``force-share=on`` requires ``read-only=on``. 1336 1337 ``cache.direct`` 1338 The host page cache can be avoided with ``cache.direct=on``. 1339 This will attempt to do disk IO directly to the guest's 1340 memory. QEMU may still perform an internal copy of the data. 1341 1342 ``cache.no-flush`` 1343 In case you don't care about data integrity over host 1344 failures, you can use ``cache.no-flush=on``. This option 1345 tells QEMU that it never needs to write any data to the disk 1346 but can instead keep things in cache. If anything goes 1347 wrong, like your host losing power, the disk storage getting 1348 disconnected accidentally, etc. your image will most 1349 probably be rendered unusable. 1350 1351 ``discard=discard`` 1352 discard is one of "ignore" (or "off") or "unmap" (or "on") 1353 and controls whether ``discard`` (also known as ``trim`` or 1354 ``unmap``) requests are ignored or passed to the filesystem. 1355 Some machine types may not support discard requests. 1356 1357 ``detect-zeroes=detect-zeroes`` 1358 detect-zeroes is "off", "on" or "unmap" and enables the 1359 automatic conversion of plain zero writes by the OS to 1360 driver specific optimized zero write commands. You may even 1361 choose "unmap" if discard is set to "unmap" to allow a zero 1362 write to be converted to an ``unmap`` operation. 1363 1364 ``Driver-specific options for file`` 1365 This is the protocol-level block driver for accessing regular 1366 files. 1367 1368 ``filename`` 1369 The path to the image file in the local filesystem 1370 1371 ``aio`` 1372 Specifies the AIO backend (threads/native/io_uring, 1373 default: threads) 1374 1375 ``locking`` 1376 Specifies whether the image file is protected with Linux OFD 1377 / POSIX locks. The default is to use the Linux Open File 1378 Descriptor API if available, otherwise no lock is applied. 1379 (auto/on/off, default: auto) 1380 1381 Example: 1382 1383 :: 1384 1385 -blockdev driver=file,node-name=disk,filename=disk.img 1386 1387 ``Driver-specific options for raw`` 1388 This is the image format block driver for raw images. It is 1389 usually stacked on top of a protocol level block driver such as 1390 ``file``. 1391 1392 ``file`` 1393 Reference to or definition of the data source block driver 1394 node (e.g. a ``file`` driver node) 1395 1396 Example 1: 1397 1398 :: 1399 1400 -blockdev driver=file,node-name=disk_file,filename=disk.img 1401 -blockdev driver=raw,node-name=disk,file=disk_file 1402 1403 Example 2: 1404 1405 :: 1406 1407 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1408 1409 ``Driver-specific options for qcow2`` 1410 This is the image format block driver for qcow2 images. It is 1411 usually stacked on top of a protocol level block driver such as 1412 ``file``. 1413 1414 ``file`` 1415 Reference to or definition of the data source block driver 1416 node (e.g. a ``file`` driver node) 1417 1418 ``backing`` 1419 Reference to or definition of the backing file block device 1420 (default is taken from the image file). It is allowed to 1421 pass ``null`` here in order to disable the default backing 1422 file. 1423 1424 ``lazy-refcounts`` 1425 Whether to enable the lazy refcounts feature (on/off; 1426 default is taken from the image file) 1427 1428 ``cache-size`` 1429 The maximum total size of the L2 table and refcount block 1430 caches in bytes (default: the sum of l2-cache-size and 1431 refcount-cache-size) 1432 1433 ``l2-cache-size`` 1434 The maximum size of the L2 table cache in bytes (default: if 1435 cache-size is not specified - 32M on Linux platforms, and 8M 1436 on non-Linux platforms; otherwise, as large as possible 1437 within the cache-size, while permitting the requested or the 1438 minimal refcount cache size) 1439 1440 ``refcount-cache-size`` 1441 The maximum size of the refcount block cache in bytes 1442 (default: 4 times the cluster size; or if cache-size is 1443 specified, the part of it which is not used for the L2 1444 cache) 1445 1446 ``cache-clean-interval`` 1447 Clean unused entries in the L2 and refcount caches. The 1448 interval is in seconds. The default value is 600 on 1449 supporting platforms, and 0 on other platforms. Setting it 1450 to 0 disables this feature. 1451 1452 ``pass-discard-request`` 1453 Whether discard requests to the qcow2 device should be 1454 forwarded to the data source (on/off; default: on if 1455 discard=unmap is specified, off otherwise) 1456 1457 ``pass-discard-snapshot`` 1458 Whether discard requests for the data source should be 1459 issued when a snapshot operation (e.g. deleting a snapshot) 1460 frees clusters in the qcow2 file (on/off; default: on) 1461 1462 ``pass-discard-other`` 1463 Whether discard requests for the data source should be 1464 issued on other occasions where a cluster gets freed 1465 (on/off; default: off) 1466 1467 ``discard-no-unref`` 1468 When enabled, data clusters will remain preallocated when they are 1469 no longer used, e.g. because they are discarded or converted to 1470 zero clusters. As usual, whether the old data is discarded or kept 1471 on the protocol level (i.e. in the image file) depends on the 1472 setting of the pass-discard-request option. Keeping the clusters 1473 preallocated prevents qcow2 fragmentation that would otherwise be 1474 caused by freeing and re-allocating them later. Besides potential 1475 performance degradation, such fragmentation can lead to increased 1476 allocation of clusters past the end of the image file, 1477 resulting in image files whose file length can grow much larger 1478 than their guest disk size would suggest. 1479 If image file length is of concern (e.g. when storing qcow2 1480 images directly on block devices), you should consider enabling 1481 this option. 1482 1483 ``overlap-check`` 1484 Which overlap checks to perform for writes to the image 1485 (none/constant/cached/all; default: cached). For details or 1486 finer granularity control refer to the QAPI documentation of 1487 ``blockdev-add``. 1488 1489 Example 1: 1490 1491 :: 1492 1493 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1494 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1495 1496 Example 2: 1497 1498 :: 1499 1500 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1501 1502 ``Driver-specific options for other drivers`` 1503 Please refer to the QAPI documentation of the ``blockdev-add`` 1504 QMP command. 1505ERST 1506 1507DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1508 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1509 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1510 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1511 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1512 " [,aio=threads|native|io_uring]\n" 1513 " [,readonly=on|off][,copy-on-read=on|off]\n" 1514 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1515 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1516 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1517 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1518 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1519 " [[,iops_size=is]]\n" 1520 " [[,group=g]]\n" 1521 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1522SRST 1523``-drive option[,option[,option[,...]]]`` 1524 Define a new drive. This includes creating a block driver node (the 1525 backend) as well as a guest device, and is mostly a shortcut for 1526 defining the corresponding ``-blockdev`` and ``-device`` options. 1527 1528 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1529 In addition, it knows the following options: 1530 1531 ``file=file`` 1532 This option defines which disk image (see the :ref:`disk images` 1533 chapter in the System Emulation Users Guide) to use with this drive. 1534 If the filename contains comma, you must double it (for instance, 1535 "file=my,,file" to use file "my,file"). 1536 1537 Special files such as iSCSI devices can be specified using 1538 protocol specific URLs. See the section for "Device URL Syntax" 1539 for more information. 1540 1541 ``if=interface`` 1542 This option defines on which type on interface the drive is 1543 connected. Available types are: ide, scsi, sd, mtd, floppy, 1544 pflash, virtio, none. 1545 1546 ``bus=bus,unit=unit`` 1547 These options define where is connected the drive by defining 1548 the bus number and the unit id. 1549 1550 ``index=index`` 1551 This option defines where the drive is connected by using an 1552 index in the list of available connectors of a given interface 1553 type. 1554 1555 ``media=media`` 1556 This option defines the type of the media: disk or cdrom. 1557 1558 ``snapshot=snapshot`` 1559 snapshot is "on" or "off" and controls snapshot mode for the 1560 given drive (see ``-snapshot``). 1561 1562 ``cache=cache`` 1563 cache is "none", "writeback", "unsafe", "directsync" or 1564 "writethrough" and controls how the host cache is used to access 1565 block data. This is a shortcut that sets the ``cache.direct`` 1566 and ``cache.no-flush`` options (as in ``-blockdev``), and 1567 additionally ``cache.writeback``, which provides a default for 1568 the ``write-cache`` option of block guest devices (as in 1569 ``-device``). The modes correspond to the following settings: 1570 1571 ============= =============== ============ ============== 1572 \ cache.writeback cache.direct cache.no-flush 1573 ============= =============== ============ ============== 1574 writeback on off off 1575 none on on off 1576 writethrough off off off 1577 directsync off on off 1578 unsafe on off on 1579 ============= =============== ============ ============== 1580 1581 The default mode is ``cache=writeback``. 1582 1583 ``aio=aio`` 1584 aio is "threads", "native", or "io_uring" and selects between pthread 1585 based disk I/O, native Linux AIO, or Linux io_uring API. 1586 1587 ``format=format`` 1588 Specify which disk format will be used rather than detecting the 1589 format. Can be used to specify format=raw to avoid interpreting 1590 an untrusted format header. 1591 1592 ``werror=action,rerror=action`` 1593 Specify which action to take on write and read errors. Valid 1594 actions are: "ignore" (ignore the error and try to continue), 1595 "stop" (pause QEMU), "report" (report the error to the guest), 1596 "enospc" (pause QEMU only if the host disk is full; report the 1597 error to the guest otherwise). The default setting is 1598 ``werror=enospc`` and ``rerror=report``. 1599 1600 ``copy-on-read=copy-on-read`` 1601 copy-on-read is "on" or "off" and enables whether to copy read 1602 backing file sectors into the image file. 1603 1604 ``bps=b,bps_rd=r,bps_wr=w`` 1605 Specify bandwidth throttling limits in bytes per second, either 1606 for all request types or for reads or writes only. Small values 1607 can lead to timeouts or hangs inside the guest. A safe minimum 1608 for disks is 2 MB/s. 1609 1610 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1611 Specify bursts in bytes per second, either for all request types 1612 or for reads or writes only. Bursts allow the guest I/O to spike 1613 above the limit temporarily. 1614 1615 ``iops=i,iops_rd=r,iops_wr=w`` 1616 Specify request rate limits in requests per second, either for 1617 all request types or for reads or writes only. 1618 1619 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1620 Specify bursts in requests per second, either for all request 1621 types or for reads or writes only. Bursts allow the guest I/O to 1622 spike above the limit temporarily. 1623 1624 ``iops_size=is`` 1625 Let every is bytes of a request count as a new request for iops 1626 throttling purposes. Use this option to prevent guests from 1627 circumventing iops limits by sending fewer but larger requests. 1628 1629 ``group=g`` 1630 Join a throttling quota group with given name g. All drives that 1631 are members of the same group are accounted for together. Use 1632 this option to prevent guests from circumventing throttling 1633 limits by using many small disks instead of a single larger 1634 disk. 1635 1636 By default, the ``cache.writeback=on`` mode is used. It will report 1637 data writes as completed as soon as the data is present in the host 1638 page cache. This is safe as long as your guest OS makes sure to 1639 correctly flush disk caches where needed. If your guest OS does not 1640 handle volatile disk write caches correctly and your host crashes or 1641 loses power, then the guest may experience data corruption. 1642 1643 For such guests, you should consider using ``cache.writeback=off``. 1644 This means that the host page cache will be used to read and write 1645 data, but write notification will be sent to the guest only after 1646 QEMU has made sure to flush each write to the disk. Be aware that 1647 this has a major impact on performance. 1648 1649 When using the ``-snapshot`` option, unsafe caching is always used. 1650 1651 Copy-on-read avoids accessing the same backing file sectors 1652 repeatedly and is useful when the backing file is over a slow 1653 network. By default copy-on-read is off. 1654 1655 Instead of ``-cdrom`` you can use: 1656 1657 .. parsed-literal:: 1658 1659 |qemu_system| -drive file=file,index=2,media=cdrom 1660 1661 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1662 1663 .. parsed-literal:: 1664 1665 |qemu_system| -drive file=file,index=0,media=disk 1666 |qemu_system| -drive file=file,index=1,media=disk 1667 |qemu_system| -drive file=file,index=2,media=disk 1668 |qemu_system| -drive file=file,index=3,media=disk 1669 1670 You can open an image using pre-opened file descriptors from an fd 1671 set: 1672 1673 .. parsed-literal:: 1674 1675 |qemu_system| \\ 1676 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1677 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1678 -drive file=/dev/fdset/2,index=0,media=disk 1679 1680 You can connect a CDROM to the slave of ide0: 1681 1682 .. parsed-literal:: 1683 1684 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1685 1686 If you don't specify the "file=" argument, you define an empty 1687 drive: 1688 1689 .. parsed-literal:: 1690 1691 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1692 1693 Instead of ``-fda``, ``-fdb``, you can use: 1694 1695 .. parsed-literal:: 1696 1697 |qemu_system_x86| -drive file=file,index=0,if=floppy 1698 |qemu_system_x86| -drive file=file,index=1,if=floppy 1699 1700 By default, interface is "ide" and index is automatically 1701 incremented: 1702 1703 .. parsed-literal:: 1704 1705 |qemu_system_x86| -drive file=a -drive file=b 1706 1707 is interpreted like: 1708 1709 .. parsed-literal:: 1710 1711 |qemu_system_x86| -hda a -hdb b 1712ERST 1713 1714DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1715 "-mtdblock file use 'file' as on-board Flash memory image\n", 1716 QEMU_ARCH_ALL) 1717SRST 1718``-mtdblock file`` 1719 Use file as on-board Flash memory image. 1720ERST 1721 1722DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1723 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1724SRST 1725``-sd file`` 1726 Use file as SecureDigital card image. 1727ERST 1728 1729DEF("snapshot", 0, QEMU_OPTION_snapshot, 1730 "-snapshot write to temporary files instead of disk image files\n", 1731 QEMU_ARCH_ALL) 1732SRST 1733``-snapshot`` 1734 Write to temporary files instead of disk image files. In this case, 1735 the raw disk image you use is not written back. You can however 1736 force the write back by pressing C-a s (see the :ref:`disk images` 1737 chapter in the System Emulation Users Guide). 1738 1739 .. warning:: 1740 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1741 to manually create snapshot images to attach to your blockdev). 1742 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1743 can use the 'snapshot' property on your drive declarations 1744 instead of this global option. 1745 1746ERST 1747 1748DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1749 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1750 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1751 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1752 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1753 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1754 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1755 " [[,throttling.iops-size=is]]\n" 1756 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1757 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1758 "-fsdev synth,id=id\n", 1759 QEMU_ARCH_ALL) 1760 1761SRST 1762``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1763 \ 1764``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1765 \ 1766``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1767 \ 1768``-fsdev synth,id=id[,readonly=on]`` 1769 Define a new file system device. Valid options are: 1770 1771 ``local`` 1772 Accesses to the filesystem are done by QEMU. 1773 1774 ``proxy`` 1775 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1776 option is deprecated (since QEMU 8.1) and will be removed in a future 1777 version of QEMU. Use ``local`` instead. 1778 1779 ``synth`` 1780 Synthetic filesystem, only used by QTests. 1781 1782 ``id=id`` 1783 Specifies identifier for this device. 1784 1785 ``path=path`` 1786 Specifies the export path for the file system device. Files 1787 under this path will be available to the 9p client on the guest. 1788 1789 ``security_model=security_model`` 1790 Specifies the security model to be used for this export path. 1791 Supported security models are "passthrough", "mapped-xattr", 1792 "mapped-file" and "none". In "passthrough" security model, files 1793 are stored using the same credentials as they are created on the 1794 guest. This requires QEMU to run as root. In "mapped-xattr" 1795 security model, some of the file attributes like uid, gid, mode 1796 bits and link target are stored as file attributes. For 1797 "mapped-file" these attributes are stored in the hidden 1798 .virtfs\_metadata directory. Directories exported by this 1799 security model cannot interact with other unix tools. "none" 1800 security model is same as passthrough except the sever won't 1801 report failures if it fails to set file attributes like 1802 ownership. Security model is mandatory only for local fsdriver. 1803 Other fsdrivers (like proxy) don't take security model as a 1804 parameter. 1805 1806 ``writeout=writeout`` 1807 This is an optional argument. The only supported value is 1808 "immediate". This means that host page cache will be used to 1809 read and write data but write notification will be sent to the 1810 guest only when the data has been reported as written by the 1811 storage subsystem. 1812 1813 ``readonly=on`` 1814 Enables exporting 9p share as a readonly mount for guests. By 1815 default read-write access is given. 1816 1817 ``socket=socket`` 1818 Enables proxy filesystem driver to use passed socket file for 1819 communicating with virtfs-proxy-helper(1). 1820 1821 ``sock_fd=sock_fd`` 1822 Enables proxy filesystem driver to use passed socket descriptor 1823 for communicating with virtfs-proxy-helper(1). Usually a helper 1824 like libvirt will create socketpair and pass one of the fds as 1825 sock\_fd. 1826 1827 ``fmode=fmode`` 1828 Specifies the default mode for newly created files on the host. 1829 Works only with security models "mapped-xattr" and 1830 "mapped-file". 1831 1832 ``dmode=dmode`` 1833 Specifies the default mode for newly created directories on the 1834 host. Works only with security models "mapped-xattr" and 1835 "mapped-file". 1836 1837 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1838 Specify bandwidth throttling limits in bytes per second, either 1839 for all request types or for reads or writes only. 1840 1841 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1842 Specify bursts in bytes per second, either for all request types 1843 or for reads or writes only. Bursts allow the guest I/O to spike 1844 above the limit temporarily. 1845 1846 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1847 Specify request rate limits in requests per second, either for 1848 all request types or for reads or writes only. 1849 1850 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1851 Specify bursts in requests per second, either for all request 1852 types or for reads or writes only. Bursts allow the guest I/O to 1853 spike above the limit temporarily. 1854 1855 ``throttling.iops-size=is`` 1856 Let every is bytes of a request count as a new request for iops 1857 throttling purposes. 1858 1859 -fsdev option is used along with -device driver "virtio-9p-...". 1860 1861``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1862 Options for virtio-9p-... driver are: 1863 1864 ``type`` 1865 Specifies the variant to be used. Supported values are "pci", 1866 "ccw" or "device", depending on the machine type. 1867 1868 ``fsdev=id`` 1869 Specifies the id value specified along with -fsdev option. 1870 1871 ``mount_tag=mount_tag`` 1872 Specifies the tag name to be used by the guest to mount this 1873 export point. 1874ERST 1875 1876DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1877 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1878 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1879 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1880 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1881 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1882 QEMU_ARCH_ALL) 1883 1884SRST 1885``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1886 \ 1887``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1888 \ 1889``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1890 \ 1891``-virtfs synth,mount_tag=mount_tag`` 1892 Define a new virtual filesystem device and expose it to the guest using 1893 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1894 directory on host is made directly accessible by guest as a pass-through 1895 file system by using the 9P network protocol for communication between 1896 host and guests, if desired even accessible, shared by several guests 1897 simultaneously. 1898 1899 Note that ``-virtfs`` is actually just a convenience shortcut for its 1900 generalized form ``-fsdev -device virtio-9p-pci``. 1901 1902 The general form of pass-through file system options are: 1903 1904 ``local`` 1905 Accesses to the filesystem are done by QEMU. 1906 1907 ``proxy`` 1908 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1909 This option is deprecated (since QEMU 8.1) and will be removed in a 1910 future version of QEMU. Use ``local`` instead. 1911 1912 ``synth`` 1913 Synthetic filesystem, only used by QTests. 1914 1915 ``id=id`` 1916 Specifies identifier for the filesystem device 1917 1918 ``path=path`` 1919 Specifies the export path for the file system device. Files 1920 under this path will be available to the 9p client on the guest. 1921 1922 ``security_model=security_model`` 1923 Specifies the security model to be used for this export path. 1924 Supported security models are "passthrough", "mapped-xattr", 1925 "mapped-file" and "none". In "passthrough" security model, files 1926 are stored using the same credentials as they are created on the 1927 guest. This requires QEMU to run as root. In "mapped-xattr" 1928 security model, some of the file attributes like uid, gid, mode 1929 bits and link target are stored as file attributes. For 1930 "mapped-file" these attributes are stored in the hidden 1931 .virtfs\_metadata directory. Directories exported by this 1932 security model cannot interact with other unix tools. "none" 1933 security model is same as passthrough except the sever won't 1934 report failures if it fails to set file attributes like 1935 ownership. Security model is mandatory only for local fsdriver. 1936 Other fsdrivers (like proxy) don't take security model as a 1937 parameter. 1938 1939 ``writeout=writeout`` 1940 This is an optional argument. The only supported value is 1941 "immediate". This means that host page cache will be used to 1942 read and write data but write notification will be sent to the 1943 guest only when the data has been reported as written by the 1944 storage subsystem. 1945 1946 ``readonly=on`` 1947 Enables exporting 9p share as a readonly mount for guests. By 1948 default read-write access is given. 1949 1950 ``socket=socket`` 1951 Enables proxy filesystem driver to use passed socket file for 1952 communicating with virtfs-proxy-helper(1). Usually a helper like 1953 libvirt will create socketpair and pass one of the fds as 1954 sock\_fd. 1955 1956 ``sock_fd`` 1957 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1958 socket descriptor for interfacing with virtfs-proxy-helper(1). 1959 1960 ``fmode=fmode`` 1961 Specifies the default mode for newly created files on the host. 1962 Works only with security models "mapped-xattr" and 1963 "mapped-file". 1964 1965 ``dmode=dmode`` 1966 Specifies the default mode for newly created directories on the 1967 host. Works only with security models "mapped-xattr" and 1968 "mapped-file". 1969 1970 ``mount_tag=mount_tag`` 1971 Specifies the tag name to be used by the guest to mount this 1972 export point. 1973 1974 ``multidevs=multidevs`` 1975 Specifies how to deal with multiple devices being shared with a 1976 9p export. Supported behaviours are either "remap", "forbid" or 1977 "warn". The latter is the default behaviour on which virtfs 9p 1978 expects only one device to be shared with the same export, and 1979 if more than one device is shared and accessed via the same 9p 1980 export then only a warning message is logged (once) by qemu on 1981 host side. In order to avoid file ID collisions on guest you 1982 should either create a separate virtfs export for each device to 1983 be shared with guests (recommended way) or you might use "remap" 1984 instead which allows you to share multiple devices with only one 1985 export instead, which is achieved by remapping the original 1986 inode numbers from host to guest in a way that would prevent 1987 such collisions. Remapping inodes in such use cases is required 1988 because the original device IDs from host are never passed and 1989 exposed on guest. Instead all files of an export shared with 1990 virtfs always share the same device id on guest. So two files 1991 with identical inode numbers but from actually different devices 1992 on host would otherwise cause a file ID collision and hence 1993 potential misbehaviours on guest. "forbid" on the other hand 1994 assumes like "warn" that only one device is shared by the same 1995 export, however it will not only log a warning message but also 1996 deny access to additional devices on guest. Note though that 1997 "forbid" does currently not block all possible file access 1998 operations (e.g. readdir() would still return entries from other 1999 devices). 2000ERST 2001 2002DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 2003 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 2004 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 2005 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 2006 " [,timeout=timeout]\n" 2007 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2008 2009SRST 2010``-iscsi`` 2011 Configure iSCSI session parameters. 2012ERST 2013 2014DEFHEADING() 2015 2016DEFHEADING(USB convenience options:) 2017 2018DEF("usb", 0, QEMU_OPTION_usb, 2019 "-usb enable on-board USB host controller (if not enabled by default)\n", 2020 QEMU_ARCH_ALL) 2021SRST 2022``-usb`` 2023 Enable USB emulation on machine types with an on-board USB host 2024 controller (if not enabled by default). Note that on-board USB host 2025 controllers may not support USB 3.0. In this case 2026 ``-device qemu-xhci`` can be used instead on machines with PCI. 2027ERST 2028 2029DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2030 "-usbdevice name add the host or guest USB device 'name'\n", 2031 QEMU_ARCH_ALL) 2032SRST 2033``-usbdevice devname`` 2034 Add the USB device devname, and enable an on-board USB controller 2035 if possible and necessary (just like it can be done via 2036 ``-machine usb=on``). Note that this option is mainly intended for 2037 the user's convenience only. More fine-grained control can be 2038 achieved by selecting a USB host controller (if necessary) and the 2039 desired USB device via the ``-device`` option instead. For example, 2040 instead of using ``-usbdevice mouse`` it is possible to use 2041 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2042 to a USB 3.0 controller instead (at least on machines that support 2043 PCI and do not have an USB controller enabled by default yet). 2044 For more details, see the chapter about 2045 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2046 Possible devices for devname are: 2047 2048 ``braille`` 2049 Braille device. This will use BrlAPI to display the braille 2050 output on a real or fake device (i.e. it also creates a 2051 corresponding ``braille`` chardev automatically beside the 2052 ``usb-braille`` USB device). 2053 2054 ``keyboard`` 2055 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2056 2057 ``mouse`` 2058 Virtual Mouse. This will override the PS/2 mouse emulation when 2059 activated. 2060 2061 ``tablet`` 2062 Pointer device that uses absolute coordinates (like a 2063 touchscreen). This means QEMU is able to report the mouse 2064 position without having to grab the mouse. Also overrides the 2065 PS/2 mouse emulation when activated. 2066 2067 ``wacom-tablet`` 2068 Wacom PenPartner USB tablet. 2069 2070 2071ERST 2072 2073DEFHEADING() 2074 2075DEFHEADING(Display options:) 2076 2077DEF("display", HAS_ARG, QEMU_OPTION_display, 2078#if defined(CONFIG_SPICE) 2079 "-display spice-app[,gl=on|off]\n" 2080#endif 2081#if defined(CONFIG_SDL) 2082 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2083 " [,window-close=on|off]\n" 2084#endif 2085#if defined(CONFIG_GTK) 2086 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2087 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2088 " [,show-menubar=on|off]\n" 2089#endif 2090#if defined(CONFIG_VNC) 2091 "-display vnc=<display>[,<optargs>]\n" 2092#endif 2093#if defined(CONFIG_CURSES) 2094 "-display curses[,charset=<encoding>]\n" 2095#endif 2096#if defined(CONFIG_COCOA) 2097 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2098 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2099 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2100#endif 2101#if defined(CONFIG_OPENGL) 2102 "-display egl-headless[,rendernode=<file>]\n" 2103#endif 2104#if defined(CONFIG_DBUS_DISPLAY) 2105 "-display dbus[,addr=<dbusaddr>]\n" 2106 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2107#endif 2108 "-display none\n" 2109 " select display backend type\n" 2110 " The default display is equivalent to\n " 2111#if defined(CONFIG_GTK) 2112 "\"-display gtk\"\n" 2113#elif defined(CONFIG_SDL) 2114 "\"-display sdl\"\n" 2115#elif defined(CONFIG_COCOA) 2116 "\"-display cocoa\"\n" 2117#elif defined(CONFIG_VNC) 2118 "\"-vnc localhost:0,to=99,id=default\"\n" 2119#else 2120 "\"-display none\"\n" 2121#endif 2122 , QEMU_ARCH_ALL) 2123SRST 2124``-display type`` 2125 Select type of display to use. Use ``-display help`` to list the available 2126 display types. Valid values for type are 2127 2128 ``spice-app[,gl=on|off]`` 2129 Start QEMU as a Spice server and launch the default Spice client 2130 application. The Spice server will redirect the serial consoles 2131 and QEMU monitors. (Since 4.0) 2132 2133 ``dbus`` 2134 Export the display over D-Bus interfaces. (Since 7.0) 2135 2136 The connection is registered with the "org.qemu" name (and queued when 2137 already owned). 2138 2139 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2140 2141 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2142 2143 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2144 will share framebuffers with DMABUF file descriptors). 2145 2146 ``sdl`` 2147 Display video output via SDL (usually in a separate graphics 2148 window; see the SDL documentation for other possibilities). 2149 Valid parameters are: 2150 2151 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2152 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2153 either ``lshift-lctrl-lalt`` or ``rctrl``. 2154 2155 ``gl=on|off|core|es`` : Use OpenGL for displaying 2156 2157 ``show-cursor=on|off`` : Force showing the mouse cursor 2158 2159 ``window-close=on|off`` : Allow to quit qemu with window close button 2160 2161 ``gtk`` 2162 Display video output in a GTK window. This interface provides 2163 drop-down menus and other UI elements to configure and control 2164 the VM during runtime. Valid parameters are: 2165 2166 ``full-screen=on|off`` : Start in fullscreen mode 2167 2168 ``gl=on|off`` : Use OpenGL for displaying 2169 2170 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2171 2172 ``show-tabs=on|off`` : Display the tab bar for switching between the 2173 various graphical interfaces (e.g. VGA and 2174 virtual console character devices) by default. 2175 2176 ``show-cursor=on|off`` : Force showing the mouse cursor 2177 2178 ``window-close=on|off`` : Allow to quit qemu with window close button 2179 2180 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2181 2182 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2183 defaults to "off" 2184 2185 ``curses[,charset=<encoding>]`` 2186 Display video output via curses. For graphics device models 2187 which support a text mode, QEMU can display this output using a 2188 curses/ncurses interface. Nothing is displayed when the graphics 2189 device is in graphical mode or if the graphics device does not 2190 support a text mode. Generally only the VGA device models 2191 support text mode. The font charset used by the guest can be 2192 specified with the ``charset`` option, for example 2193 ``charset=CP850`` for IBM CP850 encoding. The default is 2194 ``CP437``. 2195 2196 ``cocoa`` 2197 Display video output in a Cocoa window. Mac only. This interface 2198 provides drop-down menus and other UI elements to configure and 2199 control the VM during runtime. Valid parameters are: 2200 2201 ``full-grab=on|off`` : Capture all key presses, including system combos. 2202 This requires accessibility permissions, since it 2203 performs a global grab on key events. 2204 (default: off) See 2205 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2206 2207 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2208 key codes match their position on non-Mac 2209 keyboards and you can use Meta/Super and Alt 2210 where you expect them. (default: off) 2211 2212 ``show-cursor=on|off`` : Force showing the mouse cursor 2213 2214 ``left-command-key=on|off`` : Disable forwarding left command key to host 2215 2216 ``full-screen=on|off`` : Start in fullscreen mode 2217 2218 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2219 defaults to "off" 2220 2221 ``egl-headless[,rendernode=<file>]`` 2222 Offload all OpenGL operations to a local DRI device. For any 2223 graphical display, this display needs to be paired with either 2224 VNC or SPICE displays. 2225 2226 ``vnc=<display>`` 2227 Start a VNC server on display <display> 2228 2229 ``none`` 2230 Do not display video output. The guest will still see an 2231 emulated graphics card, but its output will not be displayed to 2232 the QEMU user. This option differs from the -nographic option in 2233 that it only affects what is done with video output; -nographic 2234 also changes the destination of the serial and parallel port 2235 data. 2236ERST 2237 2238DEF("nographic", 0, QEMU_OPTION_nographic, 2239 "-nographic disable graphical output and redirect serial I/Os to console\n", 2240 QEMU_ARCH_ALL) 2241SRST 2242``-nographic`` 2243 Normally, if QEMU is compiled with graphical window support, it 2244 displays output such as guest graphics, guest console, and the QEMU 2245 monitor in a window. With this option, you can totally disable 2246 graphical output so that QEMU is a simple command line application. 2247 The emulated serial port is redirected on the console and muxed with 2248 the monitor (unless redirected elsewhere explicitly). Therefore, you 2249 can still use QEMU to debug a Linux kernel with a serial console. 2250 Use C-a h for help on switching between the console and monitor. 2251ERST 2252 2253#ifdef CONFIG_SPICE 2254DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2255 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2256 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2257 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2258 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2259 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2260 " [,tls-ciphers=<list>]\n" 2261 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2262 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2263 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2264 " [,password-secret=<secret-id>]\n" 2265 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2266 " [,jpeg-wan-compression=[auto|never|always]]\n" 2267 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2268 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2269 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2270 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2271 " [,gl=[on|off]][,rendernode=<file>]\n" 2272 " enable spice\n" 2273 " at least one of {port, tls-port} is mandatory\n", 2274 QEMU_ARCH_ALL) 2275#endif 2276SRST 2277``-spice option[,option[,...]]`` 2278 Enable the spice remote desktop protocol. Valid options are 2279 2280 ``port=<nr>`` 2281 Set the TCP port spice is listening on for plaintext channels. 2282 2283 ``addr=<addr>`` 2284 Set the IP address spice is listening on. Default is any 2285 address. 2286 2287 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2288 Force using the specified IP version. 2289 2290 ``password-secret=<secret-id>`` 2291 Set the ID of the ``secret`` object containing the password 2292 you need to authenticate. 2293 2294 ``sasl=on|off`` 2295 Require that the client use SASL to authenticate with the spice. 2296 The exact choice of authentication method used is controlled 2297 from the system / user's SASL configuration file for the 'qemu' 2298 service. This is typically found in /etc/sasl2/qemu.conf. If 2299 running QEMU as an unprivileged user, an environment variable 2300 SASL\_CONF\_PATH can be used to make it search alternate 2301 locations for the service config. While some SASL auth methods 2302 can also provide data encryption (eg GSSAPI), it is recommended 2303 that SASL always be combined with the 'tls' and 'x509' settings 2304 to enable use of SSL and server certificates. This ensures a 2305 data encryption preventing compromise of authentication 2306 credentials. 2307 2308 ``disable-ticketing=on|off`` 2309 Allow client connects without authentication. 2310 2311 ``disable-copy-paste=on|off`` 2312 Disable copy paste between the client and the guest. 2313 2314 ``disable-agent-file-xfer=on|off`` 2315 Disable spice-vdagent based file-xfer between the client and the 2316 guest. 2317 2318 ``tls-port=<nr>`` 2319 Set the TCP port spice is listening on for encrypted channels. 2320 2321 ``x509-dir=<dir>`` 2322 Set the x509 file directory. Expects same filenames as -vnc 2323 $display,x509=$dir 2324 2325 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2326 The x509 file names can also be configured individually. 2327 2328 ``tls-ciphers=<list>`` 2329 Specify which ciphers to use. 2330 2331 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2332 Force specific channel to be used with or without TLS 2333 encryption. The options can be specified multiple times to 2334 configure multiple channels. The special name "default" can be 2335 used to set the default mode. For channels which are not 2336 explicitly forced into one mode the spice client is allowed to 2337 pick tls/plaintext as he pleases. 2338 2339 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2340 Configure image compression (lossless). Default is auto\_glz. 2341 2342 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2343 Configure wan image compression (lossy for slow links). Default 2344 is auto. 2345 2346 ``streaming-video=[off|all|filter]`` 2347 Configure video stream detection. Default is off. 2348 2349 ``agent-mouse=[on|off]`` 2350 Enable/disable passing mouse events via vdagent. Default is on. 2351 2352 ``playback-compression=[on|off]`` 2353 Enable/disable audio stream compression (using celt 0.5.1). 2354 Default is on. 2355 2356 ``seamless-migration=[on|off]`` 2357 Enable/disable spice seamless migration. Default is off. 2358 2359 ``gl=[on|off]`` 2360 Enable/disable OpenGL context. Default is off. 2361 2362 ``rendernode=<file>`` 2363 DRM render node for OpenGL rendering. If not specified, it will 2364 pick the first available. (Since 2.9) 2365ERST 2366 2367DEF("portrait", 0, QEMU_OPTION_portrait, 2368 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2369 QEMU_ARCH_ALL) 2370SRST 2371``-portrait`` 2372 Rotate graphical output 90 deg left (only PXA LCD). 2373ERST 2374 2375DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2376 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2377 QEMU_ARCH_ALL) 2378SRST 2379``-rotate deg`` 2380 Rotate graphical output some deg left (only PXA LCD). 2381ERST 2382 2383DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2384 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2385 " select video card type\n", QEMU_ARCH_ALL) 2386SRST 2387``-vga type`` 2388 Select type of VGA card to emulate. Valid values for type are 2389 2390 ``cirrus`` 2391 Cirrus Logic GD5446 Video card. All Windows versions starting 2392 from Windows 95 should recognize and use this graphic card. For 2393 optimal performances, use 16 bit color depth in the guest and 2394 the host OS. (This card was the default before QEMU 2.2) 2395 2396 ``std`` 2397 Standard VGA card with Bochs VBE extensions. If your guest OS 2398 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2399 you want to use high resolution modes (>= 1280x1024x16) then you 2400 should use this option. (This card is the default since QEMU 2401 2.2) 2402 2403 ``vmware`` 2404 VMWare SVGA-II compatible adapter. Use it if you have 2405 sufficiently recent XFree86/XOrg server or Windows guest with a 2406 driver for this card. 2407 2408 ``qxl`` 2409 QXL paravirtual graphic card. It is VGA compatible (including 2410 VESA 2.0 VBE support). Works best with qxl guest drivers 2411 installed though. Recommended choice when using the spice 2412 protocol. 2413 2414 ``tcx`` 2415 (sun4m only) Sun TCX framebuffer. This is the default 2416 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2417 colour depths at a fixed resolution of 1024x768. 2418 2419 ``cg3`` 2420 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2421 framebuffer for sun4m machines available in both 1024x768 2422 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2423 wishing to run older Solaris versions. 2424 2425 ``virtio`` 2426 Virtio VGA card. 2427 2428 ``none`` 2429 Disable VGA card. 2430ERST 2431 2432DEF("full-screen", 0, QEMU_OPTION_full_screen, 2433 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2434SRST 2435``-full-screen`` 2436 Start in full screen. 2437ERST 2438 2439DEF("g", HAS_ARG, QEMU_OPTION_g , 2440 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2441 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2442SRST 2443``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2444 Set the initial graphical resolution and depth (PPC, SPARC only). 2445 2446 For PPC the default is 800x600x32. 2447 2448 For SPARC with the TCX graphics device, the default is 1024x768x8 2449 with the option of 1024x768x24. For cgthree, the default is 2450 1024x768x8 with the option of 1152x900x8 for people who wish to use 2451 OBP. 2452ERST 2453 2454#ifdef CONFIG_VNC 2455DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2456 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2457#endif 2458SRST 2459``-vnc display[,option[,option[,...]]]`` 2460 Normally, if QEMU is compiled with graphical window support, it 2461 displays output such as guest graphics, guest console, and the QEMU 2462 monitor in a window. With this option, you can have QEMU listen on 2463 VNC display display and redirect the VGA display over the VNC 2464 session. It is very useful to enable the usb tablet device when 2465 using this option (option ``-device usb-tablet``). When using the 2466 VNC display, you must use the ``-k`` parameter to set the keyboard 2467 layout if you are not using en-us. Valid syntax for the display is 2468 2469 ``to=L`` 2470 With this option, QEMU will try next available VNC displays, 2471 until the number L, if the origianlly defined "-vnc display" is 2472 not available, e.g. port 5900+display is already used by another 2473 application. By default, to=0. 2474 2475 ``host:d`` 2476 TCP connections will only be allowed from host on display d. By 2477 convention the TCP port is 5900+d. Optionally, host can be 2478 omitted in which case the server will accept connections from 2479 any host. 2480 2481 ``unix:path`` 2482 Connections will be allowed over UNIX domain sockets where path 2483 is the location of a unix socket to listen for connections on. 2484 2485 ``none`` 2486 VNC is initialized but not started. The monitor ``change`` 2487 command can be used to later start the VNC server. 2488 2489 Following the display value there may be one or more option flags 2490 separated by commas. Valid options are 2491 2492 ``reverse=on|off`` 2493 Connect to a listening VNC client via a "reverse" connection. 2494 The client is specified by the display. For reverse network 2495 connections (host:d,``reverse``), the d argument is a TCP port 2496 number, not a display number. 2497 2498 ``websocket=on|off`` 2499 Opens an additional TCP listening port dedicated to VNC 2500 Websocket connections. If a bare websocket option is given, the 2501 Websocket port is 5700+display. An alternative port can be 2502 specified with the syntax ``websocket``\ =port. 2503 2504 If host is specified connections will only be allowed from this 2505 host. It is possible to control the websocket listen address 2506 independently, using the syntax ``websocket``\ =host:port. 2507 2508 If no TLS credentials are provided, the websocket connection 2509 runs in unencrypted mode. If TLS credentials are provided, the 2510 websocket connection requires encrypted client connections. 2511 2512 ``password=on|off`` 2513 Require that password based authentication is used for client 2514 connections. 2515 2516 The password must be set separately using the ``set_password`` 2517 command in the :ref:`QEMU monitor`. The 2518 syntax to change your password is: 2519 ``set_password <protocol> <password>`` where <protocol> could be 2520 either "vnc" or "spice". 2521 2522 If you would like to change <protocol> password expiration, you 2523 should use ``expire_password <protocol> <expiration-time>`` 2524 where expiration time could be one of the following options: 2525 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2526 make password expire in 60 seconds, or 1335196800 to make 2527 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2528 this date and time). 2529 2530 You can also use keywords "now" or "never" for the expiration 2531 time to allow <protocol> password to expire immediately or never 2532 expire. 2533 2534 ``password-secret=<secret-id>`` 2535 Require that password based authentication is used for client 2536 connections, using the password provided by the ``secret`` 2537 object identified by ``secret-id``. 2538 2539 ``tls-creds=ID`` 2540 Provides the ID of a set of TLS credentials to use to secure the 2541 VNC server. They will apply to both the normal VNC server socket 2542 and the websocket socket (if enabled). Setting TLS credentials 2543 will cause the VNC server socket to enable the VeNCrypt auth 2544 mechanism. The credentials should have been previously created 2545 using the ``-object tls-creds`` argument. 2546 2547 ``tls-authz=ID`` 2548 Provides the ID of the QAuthZ authorization object against which 2549 the client's x509 distinguished name will validated. This object 2550 is only resolved at time of use, so can be deleted and recreated 2551 on the fly while the VNC server is active. If missing, it will 2552 default to denying access. 2553 2554 ``sasl=on|off`` 2555 Require that the client use SASL to authenticate with the VNC 2556 server. The exact choice of authentication method used is 2557 controlled from the system / user's SASL configuration file for 2558 the 'qemu' service. This is typically found in 2559 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2560 an environment variable SASL\_CONF\_PATH can be used to make it 2561 search alternate locations for the service config. While some 2562 SASL auth methods can also provide data encryption (eg GSSAPI), 2563 it is recommended that SASL always be combined with the 'tls' 2564 and 'x509' settings to enable use of SSL and server 2565 certificates. This ensures a data encryption preventing 2566 compromise of authentication credentials. See the 2567 :ref:`VNC security` section in the System Emulation Users Guide 2568 for details on using SASL authentication. 2569 2570 ``sasl-authz=ID`` 2571 Provides the ID of the QAuthZ authorization object against which 2572 the client's SASL username will validated. This object is only 2573 resolved at time of use, so can be deleted and recreated on the 2574 fly while the VNC server is active. If missing, it will default 2575 to denying access. 2576 2577 ``acl=on|off`` 2578 Legacy method for enabling authorization of clients against the 2579 x509 distinguished name and SASL username. It results in the 2580 creation of two ``authz-list`` objects with IDs of 2581 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2582 objects must be configured with the HMP ACL commands. 2583 2584 This option is deprecated and should no longer be used. The new 2585 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2586 2587 ``lossy=on|off`` 2588 Enable lossy compression methods (gradient, JPEG, ...). If this 2589 option is set, VNC client may receive lossy framebuffer updates 2590 depending on its encoding settings. Enabling this option can 2591 save a lot of bandwidth at the expense of quality. 2592 2593 ``non-adaptive=on|off`` 2594 Disable adaptive encodings. Adaptive encodings are enabled by 2595 default. An adaptive encoding will try to detect frequently 2596 updated screen regions, and send updates in these regions using 2597 a lossy encoding (like JPEG). This can be really helpful to save 2598 bandwidth when playing videos. Disabling adaptive encodings 2599 restores the original static behavior of encodings like Tight. 2600 2601 ``share=[allow-exclusive|force-shared|ignore]`` 2602 Set display sharing policy. 'allow-exclusive' allows clients to 2603 ask for exclusive access. As suggested by the rfb spec this is 2604 implemented by dropping other connections. Connecting multiple 2605 clients in parallel requires all clients asking for a shared 2606 session (vncviewer: -shared switch). This is the default. 2607 'force-shared' disables exclusive client access. Useful for 2608 shared desktop sessions, where you don't want someone forgetting 2609 specify -shared disconnect everybody else. 'ignore' completely 2610 ignores the shared flag and allows everybody connect 2611 unconditionally. Doesn't conform to the rfb spec but is 2612 traditional QEMU behavior. 2613 2614 ``key-delay-ms`` 2615 Set keyboard delay, for key down and key up events, in 2616 milliseconds. Default is 10. Keyboards are low-bandwidth 2617 devices, so this slowdown can help the device and guest to keep 2618 up and not lose events in case events are arriving in bulk. 2619 Possible causes for the latter are flaky network connections, or 2620 scripts for automated testing. 2621 2622 ``audiodev=audiodev`` 2623 Use the specified audiodev when the VNC client requests audio 2624 transmission. When not using an -audiodev argument, this option 2625 must be omitted, otherwise is must be present and specify a 2626 valid audiodev. 2627 2628 ``power-control=on|off`` 2629 Permit the remote client to issue shutdown, reboot or reset power 2630 control requests. 2631ERST 2632 2633ARCHHEADING(, QEMU_ARCH_I386) 2634 2635ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2636 2637DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2638 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2639 QEMU_ARCH_I386) 2640SRST 2641``-win2k-hack`` 2642 Use it when installing Windows 2000 to avoid a disk full bug. After 2643 Windows 2000 is installed, you no longer need this option (this 2644 option slows down the IDE transfers). 2645ERST 2646 2647DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2648 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2649 QEMU_ARCH_I386) 2650SRST 2651``-no-fd-bootchk`` 2652 Disable boot signature checking for floppy disks in BIOS. May be 2653 needed to boot from old floppy disks. 2654ERST 2655 2656DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2657 "-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" 2658 " ACPI table description\n", QEMU_ARCH_I386) 2659SRST 2660``-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]...]`` 2661 Add ACPI table with specified header fields and context from 2662 specified files. For file=, take whole ACPI table from the specified 2663 files, including all ACPI headers (possible overridden by other 2664 options). For data=, only data portion of the table is used, all 2665 header information is specified in the command line. If a SLIC table 2666 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2667 fields will override the same in the RSDT and the FADT (a.k.a. 2668 FACP), in order to ensure the field matches required by the 2669 Microsoft SLIC spec and the ACPI spec. 2670ERST 2671 2672DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2673 "-smbios file=binary\n" 2674 " load SMBIOS entry from binary file\n" 2675 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2676 " [,uefi=on|off]\n" 2677 " specify SMBIOS type 0 fields\n" 2678 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2679 " [,uuid=uuid][,sku=str][,family=str]\n" 2680 " specify SMBIOS type 1 fields\n" 2681 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2682 " [,asset=str][,location=str]\n" 2683 " specify SMBIOS type 2 fields\n" 2684 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2685 " [,sku=str]\n" 2686 " specify SMBIOS type 3 fields\n" 2687 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2688 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2689 " [,processor-id=%d]\n" 2690 " specify SMBIOS type 4 fields\n" 2691 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2692 " specify SMBIOS type 8 fields\n" 2693 "-smbios type=11[,value=str][,path=filename]\n" 2694 " specify SMBIOS type 11 fields\n" 2695 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2696 " [,asset=str][,part=str][,speed=%d]\n" 2697 " specify SMBIOS type 17 fields\n" 2698 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2699 " specify SMBIOS type 41 fields\n", 2700 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2701SRST 2702``-smbios file=binary`` 2703 Load SMBIOS entry from binary file. 2704 2705``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2706 Specify SMBIOS type 0 fields 2707 2708``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2709 Specify SMBIOS type 1 fields 2710 2711``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2712 Specify SMBIOS type 2 fields 2713 2714``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2715 Specify SMBIOS type 3 fields 2716 2717``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2718 Specify SMBIOS type 4 fields 2719 2720``-smbios type=11[,value=str][,path=filename]`` 2721 Specify SMBIOS type 11 fields 2722 2723 This argument can be repeated multiple times, and values are added in the order they are parsed. 2724 Applications intending to use OEM strings data are encouraged to use their application name as 2725 a prefix for the value string. This facilitates passing information for multiple applications 2726 concurrently. 2727 2728 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2729 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2730 2731 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2732 the SMBIOS table in the order in which they appear. 2733 2734 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2735 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2736 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2737 data set, for example, by specifying the serial ID of a block device. 2738 2739 An example passing three strings is 2740 2741 .. parsed-literal:: 2742 2743 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2744 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2745 path=/some/file/with/oemstringsdata.txt 2746 2747 In the guest OS this is visible with the ``dmidecode`` command 2748 2749 .. parsed-literal:: 2750 2751 $ dmidecode -t 11 2752 Handle 0x0E00, DMI type 11, 5 bytes 2753 OEM Strings 2754 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2755 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2756 String 3: myapp:some extra data 2757 2758 2759``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2760 Specify SMBIOS type 17 fields 2761 2762``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2763 Specify SMBIOS type 41 fields 2764 2765 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2766 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2767 position on the PCI bus. 2768 2769 Here is an example of use: 2770 2771 .. parsed-literal:: 2772 2773 -netdev user,id=internet \\ 2774 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2775 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2776 2777 In the guest OS, the device should then appear as ``eno1``: 2778 2779 ..parsed-literal:: 2780 2781 $ ip -brief l 2782 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2783 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2784 2785 Currently, the PCI device has to be attached to the root bus. 2786 2787ERST 2788 2789DEFHEADING() 2790 2791DEFHEADING(Network options:) 2792 2793DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2794#ifdef CONFIG_SLIRP 2795 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2796 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2797 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2798 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2799 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2800#ifndef _WIN32 2801 "[,smb=dir[,smbserver=addr]]\n" 2802#endif 2803 " configure a user mode network backend with ID 'str',\n" 2804 " its DHCP server and optional services\n" 2805#endif 2806#ifdef _WIN32 2807 "-netdev tap,id=str,ifname=name\n" 2808 " configure a host TAP network backend with ID 'str'\n" 2809#else 2810 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2811 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2812 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2813 " [,poll-us=n]\n" 2814 " configure a host TAP network backend with ID 'str'\n" 2815 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2816 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2817 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2818 " to deconfigure it\n" 2819 " use '[down]script=no' to disable script execution\n" 2820 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2821 " configure it\n" 2822 " use 'fd=h' to connect to an already opened TAP interface\n" 2823 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2824 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2825 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2826 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2827 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2828 " use vhost=on to enable experimental in kernel accelerator\n" 2829 " (only has effect for virtio guests which use MSIX)\n" 2830 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2831 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2832 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2833 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2834 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2835 " spent on busy polling for vhost net\n" 2836 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2837 " configure a host TAP network backend with ID 'str' that is\n" 2838 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2839 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2840#endif 2841#ifdef __linux__ 2842 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2843 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2844 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2845 " [,rxcookie=rxcookie][,offset=offset]\n" 2846 " configure a network backend with ID 'str' connected to\n" 2847 " an Ethernet over L2TPv3 pseudowire.\n" 2848 " Linux kernel 3.3+ as well as most routers can talk\n" 2849 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2850 " VM to a router and even VM to Host. It is a nearly-universal\n" 2851 " standard (RFC3931). Note - this implementation uses static\n" 2852 " pre-configured tunnels (same as the Linux kernel).\n" 2853 " use 'src=' to specify source address\n" 2854 " use 'dst=' to specify destination address\n" 2855 " use 'udp=on' to specify udp encapsulation\n" 2856 " use 'srcport=' to specify source udp port\n" 2857 " use 'dstport=' to specify destination udp port\n" 2858 " use 'ipv6=on' to force v6\n" 2859 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2860 " well as a weak security measure\n" 2861 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2862 " use 'txcookie=0x012345678' to specify a txcookie\n" 2863 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2864 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2865 " use 'pincounter=on' to work around broken counter handling in peer\n" 2866 " use 'offset=X' to add an extra offset between header and data\n" 2867#endif 2868 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2869 " configure a network backend to connect to another network\n" 2870 " using a socket connection\n" 2871 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2872 " configure a network backend to connect to a multicast maddr and port\n" 2873 " use 'localaddr=addr' to specify the host address to send packets from\n" 2874 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2875 " configure a network backend to connect to another network\n" 2876 " using an UDP tunnel\n" 2877 "-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" 2878 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2879 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2880 " configure a network backend to connect to another network\n" 2881 " using a socket connection in stream mode.\n" 2882 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2883 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2884 " configure a network backend to connect to a multicast maddr and port\n" 2885 " use ``local.host=addr`` to specify the host address to send packets from\n" 2886 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2887 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2888 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2889 " configure a network backend to connect to another network\n" 2890 " using an UDP tunnel\n" 2891#ifdef CONFIG_VDE 2892 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2893 " configure a network backend to connect to port 'n' of a vde switch\n" 2894 " running on host and listening for incoming connections on 'socketpath'.\n" 2895 " Use group 'groupname' and mode 'octalmode' to change default\n" 2896 " ownership and permissions for communication port.\n" 2897#endif 2898#ifdef CONFIG_NETMAP 2899 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2900 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2901 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2902 " netmap device, defaults to '/dev/netmap')\n" 2903#endif 2904#ifdef CONFIG_AF_XDP 2905 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2906 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2907 " attach to the existing network interface 'name' with AF_XDP socket\n" 2908 " use 'mode=MODE' to specify an XDP program attach mode\n" 2909 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2910 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2911 " with inhibit=on,\n" 2912 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2913 " added to a socket map in XDP program. One socket per queue.\n" 2914 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2915 " use 'start-queue=m' to specify the first queue that should be used\n" 2916#endif 2917#ifdef CONFIG_POSIX 2918 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2919 " configure a vhost-user network, backed by a chardev 'dev'\n" 2920#endif 2921#ifdef __linux__ 2922 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2923 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2924 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2925 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2926#endif 2927#ifdef CONFIG_VMNET 2928 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2929 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2930 " configure a vmnet network backend in host mode with ID 'str',\n" 2931 " isolate this interface from others with 'isolated',\n" 2932 " configure the address range and choose a subnet mask,\n" 2933 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2934 " vmnet-host interfaces within this isolated network\n" 2935 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2936 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2937 " configure a vmnet network backend in shared mode with ID 'str',\n" 2938 " configure the address range and choose a subnet mask,\n" 2939 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2940 " isolate this interface from others with 'isolated'\n" 2941 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2942 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2943 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2944 " isolate this interface from others with 'isolated'\n" 2945#endif 2946 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2947 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2948DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2949 "-nic [tap|bridge|" 2950#ifdef CONFIG_SLIRP 2951 "user|" 2952#endif 2953#ifdef __linux__ 2954 "l2tpv3|" 2955#endif 2956#ifdef CONFIG_VDE 2957 "vde|" 2958#endif 2959#ifdef CONFIG_NETMAP 2960 "netmap|" 2961#endif 2962#ifdef CONFIG_AF_XDP 2963 "af-xdp|" 2964#endif 2965#ifdef CONFIG_POSIX 2966 "vhost-user|" 2967#endif 2968#ifdef CONFIG_VMNET 2969 "vmnet-host|vmnet-shared|vmnet-bridged|" 2970#endif 2971 "socket][,option][,...][mac=macaddr]\n" 2972 " initialize an on-board / default host NIC (using MAC address\n" 2973 " macaddr) and connect it to the given host network backend\n" 2974 "-nic none use it alone to have zero network devices (the default is to\n" 2975 " provided a 'user' network connection)\n", 2976 QEMU_ARCH_ALL) 2977DEF("net", HAS_ARG, QEMU_OPTION_net, 2978 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2979 " configure or create an on-board (or machine default) NIC and\n" 2980 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2981 "-net [" 2982#ifdef CONFIG_SLIRP 2983 "user|" 2984#endif 2985 "tap|" 2986 "bridge|" 2987#ifdef CONFIG_VDE 2988 "vde|" 2989#endif 2990#ifdef CONFIG_NETMAP 2991 "netmap|" 2992#endif 2993#ifdef CONFIG_AF_XDP 2994 "af-xdp|" 2995#endif 2996#ifdef CONFIG_VMNET 2997 "vmnet-host|vmnet-shared|vmnet-bridged|" 2998#endif 2999 "socket][,option][,option][,...]\n" 3000 " old way to initialize a host network interface\n" 3001 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3002SRST 3003``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3004 This option is a shortcut for configuring both the on-board 3005 (default) guest NIC hardware and the host network backend in one go. 3006 The host backend options are the same as with the corresponding 3007 ``-netdev`` options below. The guest NIC model can be set with 3008 ``model=modelname``. Use ``model=help`` to list the available device 3009 types. The hardware MAC address can be set with ``mac=macaddr``. 3010 3011 The following two example do exactly the same, to show how ``-nic`` 3012 can be used to shorten the command line length: 3013 3014 .. parsed-literal:: 3015 3016 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3017 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3018 3019``-nic none`` 3020 Indicate that no network devices should be configured. It is used to 3021 override the default configuration (default NIC with "user" host 3022 network backend) which is activated if no other networking options 3023 are provided. 3024 3025``-netdev user,id=id[,option][,option][,...]`` 3026 Configure user mode host network backend which requires no 3027 administrator privilege to run. Valid options are: 3028 3029 ``id=id`` 3030 Assign symbolic name for use in monitor commands. 3031 3032 ``ipv4=on|off and ipv6=on|off`` 3033 Specify that either IPv4 or IPv6 must be enabled. If neither is 3034 specified both protocols are enabled. 3035 3036 ``net=addr[/mask]`` 3037 Set IP network address the guest will see. Optionally specify 3038 the netmask, either in the form a.b.c.d or as number of valid 3039 top-most bits. Default is 10.0.2.0/24. 3040 3041 ``host=addr`` 3042 Specify the guest-visible address of the host. Default is the 3043 2nd IP in the guest network, i.e. x.x.x.2. 3044 3045 ``ipv6-net=addr[/int]`` 3046 Set IPv6 network address the guest will see (default is 3047 fec0::/64). The network prefix is given in the usual hexadecimal 3048 IPv6 address notation. The prefix size is optional, and is given 3049 as the number of valid top-most bits (default is 64). 3050 3051 ``ipv6-host=addr`` 3052 Specify the guest-visible IPv6 address of the host. Default is 3053 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3054 3055 ``restrict=on|off`` 3056 If this option is enabled, the guest will be isolated, i.e. it 3057 will not be able to contact the host and no guest IP packets 3058 will be routed over the host to the outside. This option does 3059 not affect any explicitly set forwarding rules. 3060 3061 ``hostname=name`` 3062 Specifies the client hostname reported by the built-in DHCP 3063 server. 3064 3065 ``dhcpstart=addr`` 3066 Specify the first of the 16 IPs the built-in DHCP server can 3067 assign. Default is the 15th to 31st IP in the guest network, 3068 i.e. x.x.x.15 to x.x.x.31. 3069 3070 ``dns=addr`` 3071 Specify the guest-visible address of the virtual nameserver. The 3072 address must be different from the host address. Default is the 3073 3rd IP in the guest network, i.e. x.x.x.3. 3074 3075 ``ipv6-dns=addr`` 3076 Specify the guest-visible address of the IPv6 virtual 3077 nameserver. The address must be different from the host address. 3078 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3079 3080 ``dnssearch=domain`` 3081 Provides an entry for the domain-search list sent by the 3082 built-in DHCP server. More than one domain suffix can be 3083 transmitted by specifying this option multiple times. If 3084 supported, this will cause the guest to automatically try to 3085 append the given domain suffix(es) in case a domain name can not 3086 be resolved. 3087 3088 Example: 3089 3090 .. parsed-literal:: 3091 3092 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3093 3094 ``domainname=domain`` 3095 Specifies the client domain name reported by the built-in DHCP 3096 server. 3097 3098 ``tftp=dir`` 3099 When using the user mode network stack, activate a built-in TFTP 3100 server. The files in dir will be exposed as the root of a TFTP 3101 server. The TFTP client on the guest must be configured in 3102 binary mode (use the command ``bin`` of the Unix TFTP client). 3103 3104 ``tftp-server-name=name`` 3105 In BOOTP reply, broadcast name as the "TFTP server name" 3106 (RFC2132 option 66). This can be used to advise the guest to 3107 load boot files or configurations from a different server than 3108 the host address. 3109 3110 ``bootfile=file`` 3111 When using the user mode network stack, broadcast file as the 3112 BOOTP filename. In conjunction with ``tftp``, this can be used 3113 to network boot a guest from a local directory. 3114 3115 Example (using pxelinux): 3116 3117 .. parsed-literal:: 3118 3119 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3120 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3121 3122 ``smb=dir[,smbserver=addr]`` 3123 When using the user mode network stack, activate a built-in SMB 3124 server so that Windows OSes can access to the host files in 3125 ``dir`` transparently. The IP address of the SMB server can be 3126 set to addr. By default the 4th IP in the guest network is used, 3127 i.e. x.x.x.4. 3128 3129 In the guest Windows OS, the line: 3130 3131 :: 3132 3133 10.0.2.4 smbserver 3134 3135 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3136 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3137 NT/2000). 3138 3139 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3140 3141 Note that a SAMBA server must be installed on the host OS. 3142 3143 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3144 Redirect incoming TCP or UDP connections to the host port 3145 hostport to the guest IP address guestaddr on guest port 3146 guestport. If guestaddr is not specified, its value is x.x.x.15 3147 (default first address given by the built-in DHCP server). By 3148 specifying hostaddr, the rule can be bound to a specific host 3149 interface. If no connection type is set, TCP is used. This 3150 option can be given multiple times. 3151 3152 For example, to redirect host X11 connection from screen 1 to 3153 guest screen 0, use the following: 3154 3155 .. parsed-literal:: 3156 3157 # on the host 3158 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3159 # this host xterm should open in the guest X11 server 3160 xterm -display :1 3161 3162 To redirect telnet connections from host port 5555 to telnet 3163 port on the guest, use the following: 3164 3165 .. parsed-literal:: 3166 3167 # on the host 3168 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3169 telnet localhost 5555 3170 3171 Then when you use on the host ``telnet localhost 5555``, you 3172 connect to the guest telnet server. 3173 3174 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3175 Forward guest TCP connections to the IP address server on port 3176 port to the character device dev or to a program executed by 3177 cmd:command which gets spawned for each connection. This option 3178 can be given multiple times. 3179 3180 You can either use a chardev directly and have that one used 3181 throughout QEMU's lifetime, like in the following example: 3182 3183 .. parsed-literal:: 3184 3185 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3186 # the guest accesses it 3187 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3188 3189 Or you can execute a command on every TCP connection established 3190 by the guest, so that QEMU behaves similar to an inetd process 3191 for that virtual server: 3192 3193 .. parsed-literal:: 3194 3195 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3196 # and connect the TCP stream to its stdin/stdout 3197 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3198 3199``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3200 Configure a host TAP network backend with ID id. 3201 3202 Use the network script file to configure it and the network script 3203 dfile to deconfigure it. If name is not provided, the OS 3204 automatically provides one. The default network configure script is 3205 ``/etc/qemu-ifup`` and the default network deconfigure script is 3206 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3207 disable script execution. 3208 3209 If running QEMU as an unprivileged user, use the network helper 3210 to configure the TAP interface and attach it to the bridge. 3211 The default network helper executable is 3212 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3213 ``br0``. 3214 3215 ``fd``\ =h can be used to specify the handle of an already opened 3216 host TAP interface. 3217 3218 Examples: 3219 3220 .. parsed-literal:: 3221 3222 #launch a QEMU instance with the default network script 3223 |qemu_system| linux.img -nic tap 3224 3225 .. parsed-literal:: 3226 3227 #launch a QEMU instance with two NICs, each one connected 3228 #to a TAP device 3229 |qemu_system| linux.img \\ 3230 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3231 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3232 3233 .. parsed-literal:: 3234 3235 #launch a QEMU instance with the default network helper to 3236 #connect a TAP device to bridge br0 3237 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3238 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3239 3240``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3241 Connect a host TAP network interface to a host bridge device. 3242 3243 Use the network helper helper to configure the TAP interface and 3244 attach it to the bridge. The default network helper executable is 3245 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3246 ``br0``. 3247 3248 Examples: 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 -netdev bridge,id=n1 -device virtio-net,netdev=n1 3255 3256 .. parsed-literal:: 3257 3258 #launch a QEMU instance with the default network helper to 3259 #connect a TAP device to bridge qemubr0 3260 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3261 3262``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3263 This host network backend can be used to connect the guest's network 3264 to another QEMU virtual machine using a TCP socket connection. If 3265 ``listen`` is specified, QEMU waits for incoming connections on port 3266 (host is optional). ``connect`` is used to connect to another QEMU 3267 instance using the ``listen`` option. ``fd``\ =h specifies an 3268 already opened TCP socket. 3269 3270 Example: 3271 3272 .. parsed-literal:: 3273 3274 # launch a first QEMU instance 3275 |qemu_system| linux.img \\ 3276 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3277 -netdev socket,id=n1,listen=:1234 3278 # connect the network of this instance to the network of the first instance 3279 |qemu_system| linux.img \\ 3280 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3281 -netdev socket,id=n2,connect=127.0.0.1:1234 3282 3283``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3284 Configure a socket host network backend to share the guest's network 3285 traffic with another QEMU virtual machines using a UDP multicast 3286 socket, effectively making a bus for every QEMU with same multicast 3287 address maddr and port. NOTES: 3288 3289 1. Several QEMU can be running on different hosts and share same bus 3290 (assuming correct multicast setup for these hosts). 3291 3292 2. mcast support is compatible with User Mode Linux (argument 3293 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3294 3295 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3296 3297 Example: 3298 3299 .. parsed-literal:: 3300 3301 # launch one QEMU instance 3302 |qemu_system| linux.img \\ 3303 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3304 -netdev socket,id=n1,mcast=230.0.0.1:1234 3305 # launch another QEMU instance on same "bus" 3306 |qemu_system| linux.img \\ 3307 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3308 -netdev socket,id=n2,mcast=230.0.0.1:1234 3309 # launch yet another QEMU instance on same "bus" 3310 |qemu_system| linux.img \\ 3311 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3312 -netdev socket,id=n3,mcast=230.0.0.1:1234 3313 3314 Example (User Mode Linux compat.): 3315 3316 .. parsed-literal:: 3317 3318 # launch QEMU instance (note mcast address selected is UML's default) 3319 |qemu_system| linux.img \\ 3320 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3321 -netdev socket,id=n1,mcast=239.192.168.1:1102 3322 # launch UML 3323 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3324 3325 Example (send packets from host's 1.2.3.4): 3326 3327 .. parsed-literal:: 3328 3329 |qemu_system| linux.img \\ 3330 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3331 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3332 3333``-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]`` 3334 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3335 is a popular protocol to transport Ethernet (and other Layer 2) data 3336 frames between two systems. It is present in routers, firewalls and 3337 the Linux kernel (from version 3.3 onwards). 3338 3339 This transport allows a VM to communicate to another VM, router or 3340 firewall directly. 3341 3342 ``src=srcaddr`` 3343 source address (mandatory) 3344 3345 ``dst=dstaddr`` 3346 destination address (mandatory) 3347 3348 ``udp`` 3349 select udp encapsulation (default is ip). 3350 3351 ``srcport=srcport`` 3352 source udp port. 3353 3354 ``dstport=dstport`` 3355 destination udp port. 3356 3357 ``ipv6`` 3358 force v6, otherwise defaults to v4. 3359 3360 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3361 Cookies are a weak form of security in the l2tpv3 specification. 3362 Their function is mostly to prevent misconfiguration. By default 3363 they are 32 bit. 3364 3365 ``cookie64`` 3366 Set cookie size to 64 bit instead of the default 32 3367 3368 ``counter=off`` 3369 Force a 'cut-down' L2TPv3 with no counter as in 3370 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3371 3372 ``pincounter=on`` 3373 Work around broken counter handling in peer. This may also help 3374 on networks which have packet reorder. 3375 3376 ``offset=offset`` 3377 Add an extra offset between header and data 3378 3379 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3380 the bridge br-lan on the remote Linux host 1.2.3.4: 3381 3382 .. parsed-literal:: 3383 3384 # Setup tunnel on linux host using raw ip as encapsulation 3385 # on 1.2.3.4 3386 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3387 encap udp udp_sport 16384 udp_dport 16384 3388 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3389 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3390 ifconfig vmtunnel0 mtu 1500 3391 ifconfig vmtunnel0 up 3392 brctl addif br-lan vmtunnel0 3393 3394 3395 # on 4.3.2.1 3396 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3397 3398 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3399 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3400 3401``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3402 Configure VDE backend to connect to PORT n of a vde switch running 3403 on host and listening for incoming connections on socketpath. Use 3404 GROUP groupname and MODE octalmode to change default ownership and 3405 permissions for communication port. This option is only available if 3406 QEMU has been compiled with vde support enabled. 3407 3408 Example: 3409 3410 .. parsed-literal:: 3411 3412 # launch vde switch 3413 vde_switch -F -sock /tmp/myswitch 3414 # launch QEMU instance 3415 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3416 3417``-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]`` 3418 Configure AF_XDP backend to connect to a network interface 'name' 3419 using AF_XDP socket. A specific program attach mode for a default 3420 XDP program can be forced with 'mode', defaults to best-effort, 3421 where the likely most performant mode will be in use. Number of queues 3422 'n' should generally match the number or queues in the interface, 3423 defaults to 1. Traffic arriving on non-configured device queues will 3424 not be delivered to the network backend. 3425 3426 .. parsed-literal:: 3427 3428 # set number of queues to 4 3429 ethtool -L eth0 combined 4 3430 # launch QEMU instance 3431 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3432 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3433 3434 'start-queue' option can be specified if a particular range of queues 3435 [m, m + n] should be in use. For example, this is may be necessary in 3436 order to use certain NICs in native mode. Kernel allows the driver to 3437 create a separate set of XDP queues on top of regular ones, and only 3438 these queues can be used for AF_XDP sockets. NICs that work this way 3439 may also require an additional traffic redirection with ethtool to these 3440 special queues. 3441 3442 .. parsed-literal:: 3443 3444 # set number of queues to 1 3445 ethtool -L eth0 combined 1 3446 # redirect all the traffic to the second queue (id: 1) 3447 # note: drivers may require non-empty key/mask pair. 3448 ethtool -N eth0 flow-type ether \\ 3449 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3450 ethtool -N eth0 flow-type ether \\ 3451 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3452 # launch QEMU instance 3453 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3454 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3455 3456 XDP program can also be loaded externally. In this case 'inhibit' option 3457 should be set to 'on' and 'sock-fds' provided with file descriptors for 3458 already open but not bound XDP sockets already added to a socket map for 3459 corresponding queues. One socket per queue. 3460 3461 .. parsed-literal:: 3462 3463 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3464 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3465 3466``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3467 Establish a vhost-user netdev, backed by a chardev id. The chardev 3468 should be a unix domain socket backed one. The vhost-user uses a 3469 specifically defined protocol to pass vhost ioctl replacement 3470 messages to an application on the other end of the socket. On 3471 non-MSIX guests, the feature can be forced with vhostforce. Use 3472 'queues=n' to specify the number of queues to be created for 3473 multiqueue vhost-user. 3474 3475 Example: 3476 3477 :: 3478 3479 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3480 -numa node,memdev=mem \ 3481 -chardev socket,id=chr0,path=/path/to/socket \ 3482 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3483 -device virtio-net-pci,netdev=net0 3484 3485``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3486 Establish a vhost-vdpa netdev. 3487 3488 vDPA device is a device that uses a datapath which complies with 3489 the virtio specifications with a vendor specific control path. 3490 vDPA devices can be both physically located on the hardware or 3491 emulated by software. 3492 3493``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3494 Create a hub port on the emulated hub with ID hubid. 3495 3496 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3497 instead of a single netdev. Alternatively, you can also connect the 3498 hubport to another netdev with ID nd by using the ``netdev=nd`` 3499 option. 3500 3501``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3502 Legacy option to configure or create an on-board (or machine 3503 default) Network Interface Card(NIC) and connect it either to the 3504 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3505 If model is omitted, then the default NIC model associated with the 3506 machine type is used. Note that the default NIC model may change in 3507 future QEMU releases, so it is highly recommended to always specify 3508 a model. Optionally, the MAC address can be changed to mac, the 3509 device address set to addr (PCI cards only), and a name can be 3510 assigned for use in monitor commands. Optionally, for PCI cards, you 3511 can specify the number v of MSI-X vectors that the card should have; 3512 this option currently only affects virtio cards; set v = 0 to 3513 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3514 created. QEMU can emulate several different models of network card. 3515 Use ``-net nic,model=help`` for a list of available devices for your 3516 target. 3517 3518``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3519 Configure a host network backend (with the options corresponding to 3520 the same ``-netdev`` option) and connect it to the emulated hub 0 3521 (the default hub). Use name to specify the name of the hub port. 3522ERST 3523 3524DEFHEADING() 3525 3526DEFHEADING(Character device options:) 3527 3528DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3529 "-chardev help\n" 3530 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3531 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3532 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3533 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3534 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3535 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3536 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3537 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3538 " [,logfile=PATH][,logappend=on|off]\n" 3539 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3540 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3541 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3542 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3543 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3544 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3545#ifdef _WIN32 3546 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3547 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3548#else 3549 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3550 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3551#endif 3552#ifdef CONFIG_BRLAPI 3553 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3554#endif 3555#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3556 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3557 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3558#endif 3559#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3560 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3561#endif 3562#if defined(CONFIG_SPICE) 3563 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3564 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3565#endif 3566 , QEMU_ARCH_ALL 3567) 3568 3569SRST 3570The general form of a character device option is: 3571 3572``-chardev backend,id=id[,mux=on|off][,options]`` 3573 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3574 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3575 ``pty``, ``stdio``, ``braille``, ``parallel``, 3576 ``spicevmc``, ``spiceport``. The specific backend will determine the 3577 applicable options. 3578 3579 Use ``-chardev help`` to print all available chardev backend types. 3580 3581 All devices must have an id, which can be any string up to 127 3582 characters long. It is used to uniquely identify this device in 3583 other command line directives. 3584 3585 A character device may be used in multiplexing mode by multiple 3586 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3587 a "1:N" device, and here the "1" end is your specified chardev 3588 backend, and the "N" end is the various parts of QEMU that can talk 3589 to a chardev. If you create a chardev with ``id=myid`` and 3590 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3591 and you can then configure multiple front ends to use that chardev 3592 ID for their input/output. Up to four different front ends can be 3593 connected to a single multiplexed chardev. (Without multiplexing 3594 enabled, a chardev can only be used by a single front end.) For 3595 instance you could use this to allow a single stdio chardev to be 3596 used by two serial ports and the QEMU monitor: 3597 3598 :: 3599 3600 -chardev stdio,mux=on,id=char0 \ 3601 -mon chardev=char0,mode=readline \ 3602 -serial chardev:char0 \ 3603 -serial chardev:char0 3604 3605 You can have more than one multiplexer in a system configuration; 3606 for instance you could have a TCP port multiplexed between UART 0 3607 and UART 1, and stdio multiplexed between the QEMU monitor and a 3608 parallel port: 3609 3610 :: 3611 3612 -chardev stdio,mux=on,id=char0 \ 3613 -mon chardev=char0,mode=readline \ 3614 -parallel chardev:char0 \ 3615 -chardev tcp,...,mux=on,id=char1 \ 3616 -serial chardev:char1 \ 3617 -serial chardev:char1 3618 3619 When you're using a multiplexed character device, some escape 3620 sequences are interpreted in the input. See the chapter about 3621 :ref:`keys in the character backend multiplexer` in the 3622 System Emulation Users Guide for more details. 3623 3624 Note that some other command line options may implicitly create 3625 multiplexed character backends; for instance ``-serial mon:stdio`` 3626 creates a multiplexed stdio backend connected to the serial port and 3627 the QEMU monitor, and ``-nographic`` also multiplexes the console 3628 and the monitor to stdio. 3629 3630 There is currently no support for multiplexing in the other 3631 direction (where a single QEMU front end takes input and output from 3632 multiple chardevs). 3633 3634 Every backend supports the ``logfile`` option, which supplies the 3635 path to a file to record all data transmitted via the backend. The 3636 ``logappend`` option controls whether the log file will be truncated 3637 or appended to when opened. 3638 3639The available backends are: 3640 3641``-chardev null,id=id`` 3642 A void device. This device will not emit any data, and will drop any 3643 data it receives. The null backend does not take any options. 3644 3645``-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]`` 3646 Create a two-way stream socket, which can be either a TCP or a unix 3647 socket. A unix socket will be created if ``path`` is specified. 3648 Behaviour is undefined if TCP options are specified for a unix 3649 socket. 3650 3651 ``server=on|off`` specifies that the socket shall be a listening socket. 3652 3653 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3654 to connect to a listening socket. 3655 3656 ``telnet=on|off`` specifies that traffic on the socket should interpret 3657 telnet escape sequences. 3658 3659 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3660 communication. 3661 3662 ``reconnect`` sets the timeout for reconnecting on non-server 3663 sockets when the remote end goes away. qemu will delay this many 3664 seconds and then attempt to reconnect. Zero disables reconnecting, 3665 and is the default. 3666 3667 ``tls-creds`` requests enablement of the TLS protocol for 3668 encryption, and specifies the id of the TLS credentials to use for 3669 the handshake. The credentials must be previously created with the 3670 ``-object tls-creds`` argument. 3671 3672 ``tls-auth`` provides the ID of the QAuthZ authorization object 3673 against which the client's x509 distinguished name will be 3674 validated. This object is only resolved at time of use, so can be 3675 deleted and recreated on the fly while the chardev server is active. 3676 If missing, it will default to denying access. 3677 3678 TCP and unix socket options are given below: 3679 3680 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3681 ``host`` for a listening socket specifies the local address to 3682 be bound. For a connecting socket species the remote host to 3683 connect to. ``host`` is optional for listening sockets. If not 3684 specified it defaults to ``0.0.0.0``. 3685 3686 ``port`` for a listening socket specifies the local port to be 3687 bound. For a connecting socket specifies the port on the remote 3688 host to connect to. ``port`` can be given as either a port 3689 number or a service name. ``port`` is required. 3690 3691 ``to`` is only relevant to listening sockets. If it is 3692 specified, and ``port`` cannot be bound, QEMU will attempt to 3693 bind to subsequent ports up to and including ``to`` until it 3694 succeeds. ``to`` must be specified as a port number. 3695 3696 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3697 or IPv6 must be used. If neither is specified the socket may 3698 use either protocol. 3699 3700 ``nodelay=on|off`` disables the Nagle algorithm. 3701 3702 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3703 ``path`` specifies the local path of the unix socket. ``path`` 3704 is required. 3705 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3706 rather than the filesystem. Optional, defaults to false. 3707 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3708 rather than the full sun_path length. Optional, defaults to true. 3709 3710``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3711 Sends all traffic from the guest to a remote host over UDP. 3712 3713 ``host`` specifies the remote host to connect to. If not specified 3714 it defaults to ``localhost``. 3715 3716 ``port`` specifies the port on the remote host to connect to. 3717 ``port`` is required. 3718 3719 ``localaddr`` specifies the local address to bind to. If not 3720 specified it defaults to ``0.0.0.0``. 3721 3722 ``localport`` specifies the local port to bind to. If not specified 3723 any available local port will be used. 3724 3725 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3726 If neither is specified the device may use either protocol. 3727 3728``-chardev msmouse,id=id`` 3729 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3730 does not take any options. 3731 3732``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3733 Connect to a QEMU text console. ``vc`` may optionally be given a 3734 specific size. 3735 3736 ``width`` and ``height`` specify the width and height respectively 3737 of the console, in pixels. 3738 3739 ``cols`` and ``rows`` specify that the console be sized to fit a 3740 text console with the given dimensions. 3741 3742``-chardev ringbuf,id=id[,size=size]`` 3743 Create a ring buffer with fixed size ``size``. size must be a power 3744 of two and defaults to ``64K``. 3745 3746``-chardev file,id=id,path=path[,input-path=input-path]`` 3747 Log all traffic received from the guest to a file. 3748 3749 ``path`` specifies the path of the file to be opened. This file will 3750 be created if it does not already exist, and overwritten if it does. 3751 ``path`` is required. 3752 3753 If ``input-path`` is specified, this is the path of a second file 3754 which will be used for input. If ``input-path`` is not specified, 3755 no input will be available from the chardev. 3756 3757 Note that ``input-path`` is not supported on Windows hosts. 3758 3759``-chardev pipe,id=id,path=path`` 3760 Create a two-way connection to the guest. The behaviour differs 3761 slightly between Windows hosts and other hosts: 3762 3763 On Windows, a single duplex pipe will be created at 3764 ``\\.pipe\path``. 3765 3766 On other hosts, 2 pipes will be created called ``path.in`` and 3767 ``path.out``. Data written to ``path.in`` will be received by the 3768 guest. Data written by the guest can be read from ``path.out``. QEMU 3769 will not create these fifos, and requires them to be present. 3770 3771 ``path`` forms part of the pipe path as described above. ``path`` is 3772 required. 3773 3774``-chardev console,id=id`` 3775 Send traffic from the guest to QEMU's standard output. ``console`` 3776 does not take any options. 3777 3778 ``console`` is only available on Windows hosts. 3779 3780``-chardev serial,id=id,path=path`` 3781 Send traffic from the guest to a serial device on the host. 3782 3783 On Unix hosts serial will actually accept any tty device, not only 3784 serial lines. 3785 3786 ``path`` specifies the name of the serial device to open. 3787 3788``-chardev pty,id=id`` 3789 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3790 does not take any options. 3791 3792 ``pty`` is not available on Windows hosts. 3793 3794``-chardev stdio,id=id[,signal=on|off]`` 3795 Connect to standard input and standard output of the QEMU process. 3796 3797 ``signal`` controls if signals are enabled on the terminal, that 3798 includes exiting QEMU with the key sequence Control-c. This option 3799 is enabled by default, use ``signal=off`` to disable it. 3800 3801``-chardev braille,id=id`` 3802 Connect to a local BrlAPI server. ``braille`` does not take any 3803 options. 3804 3805``-chardev parallel,id=id,path=path`` 3806 \ 3807 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3808 hosts. 3809 3810 Connect to a local parallel port. 3811 3812 ``path`` specifies the path to the parallel port device. ``path`` is 3813 required. 3814 3815``-chardev spicevmc,id=id,debug=debug,name=name`` 3816 ``spicevmc`` is only available when spice support is built in. 3817 3818 ``debug`` debug level for spicevmc 3819 3820 ``name`` name of spice channel to connect to 3821 3822 Connect to a spice virtual machine channel, such as vdiport. 3823 3824``-chardev spiceport,id=id,debug=debug,name=name`` 3825 ``spiceport`` is only available when spice support is built in. 3826 3827 ``debug`` debug level for spicevmc 3828 3829 ``name`` name of spice port to connect to 3830 3831 Connect to a spice port, allowing a Spice client to handle the 3832 traffic identified by a name (preferably a fqdn). 3833ERST 3834 3835DEFHEADING() 3836 3837#ifdef CONFIG_TPM 3838DEFHEADING(TPM device options:) 3839 3840DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3841 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3842 " use path to provide path to a character device; default is /dev/tpm0\n" 3843 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3844 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3845 "-tpmdev emulator,id=id,chardev=dev\n" 3846 " configure the TPM device using chardev backend\n", 3847 QEMU_ARCH_ALL) 3848SRST 3849The general form of a TPM device option is: 3850 3851``-tpmdev backend,id=id[,options]`` 3852 The specific backend type will determine the applicable options. The 3853 ``-tpmdev`` option creates the TPM backend and requires a 3854 ``-device`` option that specifies the TPM frontend interface model. 3855 3856 Use ``-tpmdev help`` to print all available TPM backend types. 3857 3858The available backends are: 3859 3860``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3861 (Linux-host only) Enable access to the host's TPM using the 3862 passthrough driver. 3863 3864 ``path`` specifies the path to the host's TPM device, i.e., on a 3865 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3866 default ``/dev/tpm0`` is used. 3867 3868 ``cancel-path`` specifies the path to the host TPM device's sysfs 3869 entry allowing for cancellation of an ongoing TPM command. 3870 ``cancel-path`` is optional and by default QEMU will search for the 3871 sysfs entry to use. 3872 3873 Some notes about using the host's TPM with the passthrough driver: 3874 3875 The TPM device accessed by the passthrough driver must not be used 3876 by any other application on the host. 3877 3878 Since the host's firmware (BIOS/UEFI) has already initialized the 3879 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3880 the TPM again and may therefore not show a TPM-specific menu that 3881 would otherwise allow the user to configure the TPM, e.g., allow the 3882 user to enable/disable or activate/deactivate the TPM. Further, if 3883 TPM ownership is released from within a VM then the host's TPM will 3884 get disabled and deactivated. To enable and activate the TPM again 3885 afterwards, the host has to be rebooted and the user is required to 3886 enter the firmware's menu to enable and activate the TPM. If the TPM 3887 is left disabled and/or deactivated most TPM commands will fail. 3888 3889 To create a passthrough TPM use the following two options: 3890 3891 :: 3892 3893 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3894 3895 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3896 ``tpmdev=tpm0`` in the device option. 3897 3898``-tpmdev emulator,id=id,chardev=dev`` 3899 (Linux-host only) Enable access to a TPM emulator using Unix domain 3900 socket based chardev backend. 3901 3902 ``chardev`` specifies the unique ID of a character device backend 3903 that provides connection to the software TPM server. 3904 3905 To create a TPM emulator backend device with chardev socket backend: 3906 3907 :: 3908 3909 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3910ERST 3911 3912DEFHEADING() 3913 3914#endif 3915 3916DEFHEADING(Boot Image or Kernel specific:) 3917SRST 3918There are broadly 4 ways you can boot a system with QEMU. 3919 3920 - specify a firmware and let it control finding a kernel 3921 - specify a firmware and pass a hint to the kernel to boot 3922 - direct kernel image boot 3923 - manually load files into the guest's address space 3924 3925The third method is useful for quickly testing kernels but as there is 3926no firmware to pass configuration information to the kernel the 3927hardware must either be probeable, the kernel built for the exact 3928configuration or passed some configuration data (e.g. a DTB blob) 3929which tells the kernel what drivers it needs. This exact details are 3930often hardware specific. 3931 3932The final method is the most generic way of loading images into the 3933guest address space and used mostly for ``bare metal`` type 3934development where the reset vectors of the processor are taken into 3935account. 3936 3937ERST 3938 3939SRST 3940 3941For x86 machines and some other architectures ``-bios`` will generally 3942do the right thing with whatever it is given. For other machines the 3943more strict ``-pflash`` option needs an image that is sized for the 3944flash device for the given machine type. 3945 3946Please see the :ref:`system-targets-ref` section of the manual for 3947more detailed documentation. 3948 3949ERST 3950 3951DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3952 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3953SRST 3954``-bios file`` 3955 Set the filename for the BIOS. 3956ERST 3957 3958DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3959 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3960SRST 3961``-pflash file`` 3962 Use file as a parallel flash image. 3963ERST 3964 3965SRST 3966 3967The kernel options were designed to work with Linux kernels although 3968other things (like hypervisors) can be packaged up as a kernel 3969executable image. The exact format of a executable image is usually 3970architecture specific. 3971 3972The way in which the kernel is started (what address it is loaded at, 3973what if any information is passed to it via CPU registers, the state 3974of the hardware when it is started, and so on) is also architecture 3975specific. Typically it follows the specification laid down by the 3976Linux kernel for how kernels for that architecture must be started. 3977 3978ERST 3979 3980DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3981 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3982SRST 3983``-kernel bzImage`` 3984 Use bzImage as kernel image. The kernel can be either a Linux kernel 3985 or in multiboot format. 3986ERST 3987 3988DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3989 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3990SRST 3991``-append cmdline`` 3992 Use cmdline as kernel command line 3993ERST 3994 3995DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3996 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3997SRST(initrd) 3998 3999``-initrd file`` 4000 Use file as initial ram disk. 4001 4002``-initrd "file1 arg=foo,file2"`` 4003 This syntax is only available with multiboot. 4004 4005 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4006 first module. Commas can be provided in module parameters by doubling 4007 them on the command line to escape them: 4008 4009``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4010 Multiboot only. Use bzImage as the first module with 4011 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4012 and initrd.img as the second module. 4013 4014ERST 4015 4016DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4017 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4018SRST 4019``-dtb file`` 4020 Use file as a device tree binary (dtb) image and pass it to the 4021 kernel on boot. 4022ERST 4023 4024SRST 4025 4026Finally you can also manually load images directly into the address 4027space of the guest. This is most useful for developers who already 4028know the layout of their guest and take care to ensure something sane 4029will happen when the reset vector executes. 4030 4031The generic loader can be invoked by using the loader device: 4032 4033``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4034 4035there is also the guest loader which operates in a similar way but 4036tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4037the guest image is: 4038 4039``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4040 4041ERST 4042 4043DEFHEADING() 4044 4045DEFHEADING(Debug/Expert options:) 4046 4047DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4048 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4049 " Policy for handling deprecated management interfaces\n" 4050 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4051 " Policy for handling unstable management interfaces\n", 4052 QEMU_ARCH_ALL) 4053SRST 4054``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4055 Set policy for handling deprecated management interfaces (experimental): 4056 4057 ``deprecated-input=accept`` (default) 4058 Accept deprecated commands and arguments 4059 ``deprecated-input=reject`` 4060 Reject deprecated commands and arguments 4061 ``deprecated-input=crash`` 4062 Crash on deprecated commands and arguments 4063 ``deprecated-output=accept`` (default) 4064 Emit deprecated command results and events 4065 ``deprecated-output=hide`` 4066 Suppress deprecated command results and events 4067 4068 Limitation: covers only syntactic aspects of QMP. 4069 4070``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4071 Set policy for handling unstable management interfaces (experimental): 4072 4073 ``unstable-input=accept`` (default) 4074 Accept unstable commands and arguments 4075 ``unstable-input=reject`` 4076 Reject unstable commands and arguments 4077 ``unstable-input=crash`` 4078 Crash on unstable commands and arguments 4079 ``unstable-output=accept`` (default) 4080 Emit unstable command results and events 4081 ``unstable-output=hide`` 4082 Suppress unstable command results and events 4083 4084 Limitation: covers only syntactic aspects of QMP. 4085ERST 4086 4087DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4088 "-fw_cfg [name=]<name>,file=<file>\n" 4089 " add named fw_cfg entry with contents from file\n" 4090 "-fw_cfg [name=]<name>,string=<str>\n" 4091 " add named fw_cfg entry with contents from string\n", 4092 QEMU_ARCH_ALL) 4093SRST 4094``-fw_cfg [name=]name,file=file`` 4095 Add named fw\_cfg entry with contents from file file. 4096 If the filename contains comma, you must double it (for instance, 4097 "file=my,,file" to use file "my,file"). 4098 4099``-fw_cfg [name=]name,string=str`` 4100 Add named fw\_cfg entry with contents from string str. 4101 If the string contains comma, you must double it (for instance, 4102 "string=my,,string" to use file "my,string"). 4103 4104 The terminating NUL character of the contents of str will not be 4105 included as part of the fw\_cfg item data. To insert contents with 4106 embedded NUL characters, you have to use the file parameter. 4107 4108 The fw\_cfg entries are passed by QEMU through to the guest. 4109 4110 Example: 4111 4112 :: 4113 4114 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4115 4116 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4117 from ./my\_blob.bin. 4118ERST 4119 4120DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4121 "-serial dev redirect the serial port to char device 'dev'\n", 4122 QEMU_ARCH_ALL) 4123SRST 4124``-serial dev`` 4125 Redirect the virtual serial port to host character device dev. The 4126 default device is ``vc`` in graphical mode and ``stdio`` in non 4127 graphical mode. 4128 4129 This option can be used several times to simulate up to 4 serial 4130 ports. 4131 4132 You can use ``-serial none`` to suppress the creation of default 4133 serial devices. 4134 4135 Available character devices are: 4136 4137 ``vc[:WxH]`` 4138 Virtual console. Optionally, a width and height can be given in 4139 pixel with 4140 4141 :: 4142 4143 vc:800x600 4144 4145 It is also possible to specify width or height in characters: 4146 4147 :: 4148 4149 vc:80Cx24C 4150 4151 ``pty`` 4152 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4153 4154 ``none`` 4155 No device is allocated. Note that for machine types which 4156 emulate systems where a serial device is always present in 4157 real hardware, this may be equivalent to the ``null`` option, 4158 in that the serial device is still present but all output 4159 is discarded. For boards where the number of serial ports is 4160 truly variable, this suppresses the creation of the device. 4161 4162 ``null`` 4163 A guest will see the UART or serial device as present in the 4164 machine, but all output is discarded, and there is no input. 4165 Conceptually equivalent to redirecting the output to ``/dev/null``. 4166 4167 ``chardev:id`` 4168 Use a named character device defined with the ``-chardev`` 4169 option. 4170 4171 ``/dev/XXX`` 4172 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4173 port parameters are set according to the emulated ones. 4174 4175 ``/dev/parportN`` 4176 [Linux only, parallel port only] Use host parallel port N. 4177 Currently SPP and EPP parallel port features can be used. 4178 4179 ``file:filename`` 4180 Write output to filename. No character can be read. 4181 4182 ``stdio`` 4183 [Unix only] standard input/output 4184 4185 ``pipe:filename`` 4186 name pipe filename 4187 4188 ``COMn`` 4189 [Windows only] Use host serial port n 4190 4191 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4192 This implements UDP Net Console. When remote\_host or src\_ip 4193 are not specified they default to ``0.0.0.0``. When not using a 4194 specified src\_port a random port is automatically chosen. 4195 4196 If you just want a simple readonly console you can use 4197 ``netcat`` or ``nc``, by starting QEMU with: 4198 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4199 QEMU writes something to that port it will appear in the 4200 netconsole session. 4201 4202 If you plan to send characters back via netconsole or you want 4203 to stop and start QEMU a lot of times, you should have QEMU use 4204 the same source port each time by using something like ``-serial 4205 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4206 version of netcat which can listen to a TCP port and send and 4207 receive characters via udp. If you have a patched version of 4208 netcat which activates telnet remote echo and single char 4209 transfer, then you can use the following options to set up a 4210 netcat redirector to allow telnet on port 5555 to access the 4211 QEMU port. 4212 4213 ``QEMU Options:`` 4214 -serial udp::4555@:4556 4215 4216 ``netcat options:`` 4217 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4218 4219 ``telnet options:`` 4220 localhost 5555 4221 4222 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4223 The TCP Net Console has two modes of operation. It can send the 4224 serial I/O to a location or wait for a connection from a 4225 location. By default the TCP Net Console is sent to host at the 4226 port. If you use the ``server=on`` option QEMU will wait for a client 4227 socket application to connect to the port before continuing, 4228 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4229 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4230 option only applies if ``server=no`` is set, if the connection goes 4231 down it will attempt to reconnect at the given interval. If host 4232 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4233 time is accepted. You can use ``telnet=on`` to connect to the 4234 corresponding character device. 4235 4236 ``Example to send tcp console to 192.168.0.2 port 4444`` 4237 -serial tcp:192.168.0.2:4444 4238 4239 ``Example to listen and wait on port 4444 for connection`` 4240 -serial tcp::4444,server=on 4241 4242 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4243 -serial tcp:192.168.0.100:4444,server=on,wait=off 4244 4245 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4246 The telnet protocol is used instead of raw tcp sockets. The 4247 options work the same as if you had specified ``-serial tcp``. 4248 The difference is that the port acts like a telnet server or 4249 client using telnet option negotiation. This will also allow you 4250 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4251 supports sending the break sequence. Typically in unix telnet 4252 you do it with Control-] and then type "send break" followed by 4253 pressing the enter key. 4254 4255 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4256 The WebSocket protocol is used instead of raw tcp socket. The 4257 port acts as a WebSocket server. Client mode is not supported. 4258 4259 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4260 A unix domain socket is used instead of a tcp socket. The option 4261 works the same as if you had specified ``-serial tcp`` except 4262 the unix domain socket path is used for connections. 4263 4264 ``mon:dev_string`` 4265 This is a special option to allow the monitor to be multiplexed 4266 onto another serial port. The monitor is accessed with key 4267 sequence of Control-a and then pressing c. dev\_string should be 4268 any one of the serial devices specified above. An example to 4269 multiplex the monitor onto a telnet server listening on port 4270 4444 would be: 4271 4272 ``-serial mon:telnet::4444,server=on,wait=off`` 4273 4274 When the monitor is multiplexed to stdio in this way, Ctrl+C 4275 will not terminate QEMU any more but will be passed to the guest 4276 instead. 4277 4278 ``braille`` 4279 Braille device. This will use BrlAPI to display the braille 4280 output on a real or fake device. 4281 4282 ``msmouse`` 4283 Three button serial mouse. Configure the guest to use Microsoft 4284 protocol. 4285ERST 4286 4287DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4288 "-parallel dev redirect the parallel port to char device 'dev'\n", 4289 QEMU_ARCH_ALL) 4290SRST 4291``-parallel dev`` 4292 Redirect the virtual parallel port to host device dev (same devices 4293 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4294 to use hardware devices connected on the corresponding host parallel 4295 port. 4296 4297 This option can be used several times to simulate up to 3 parallel 4298 ports. 4299 4300 Use ``-parallel none`` to disable all parallel ports. 4301ERST 4302 4303DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4304 "-monitor dev redirect the monitor to char device 'dev'\n", 4305 QEMU_ARCH_ALL) 4306SRST 4307``-monitor dev`` 4308 Redirect the monitor to host device dev (same devices as the serial 4309 port). The default device is ``vc`` in graphical mode and ``stdio`` 4310 in non graphical mode. Use ``-monitor none`` to disable the default 4311 monitor. 4312ERST 4313DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4314 "-qmp dev like -monitor but opens in 'control' mode\n", 4315 QEMU_ARCH_ALL) 4316SRST 4317``-qmp dev`` 4318 Like ``-monitor`` but opens in 'control' mode. For example, to make 4319 QMP available on localhost port 4444:: 4320 4321 -qmp tcp:localhost:4444,server=on,wait=off 4322 4323 Not all options are configurable via this syntax; for maximum 4324 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4325 4326ERST 4327DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4328 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4329 QEMU_ARCH_ALL) 4330SRST 4331``-qmp-pretty dev`` 4332 Like ``-qmp`` but uses pretty JSON formatting. 4333ERST 4334 4335DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4336 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4337SRST 4338``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4339 Set up a monitor connected to the chardev ``name``. 4340 QEMU supports two monitors: the Human Monitor Protocol 4341 (HMP; for human interaction), and the QEMU Monitor Protocol 4342 (QMP; a JSON RPC-style protocol). 4343 The default is HMP; ``mode=control`` selects QMP instead. 4344 ``pretty`` is only valid when ``mode=control``, 4345 turning on JSON pretty printing to ease 4346 human reading and debugging. 4347 4348 For example:: 4349 4350 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4351 -mon chardev=mon1,mode=control,pretty=on 4352 4353 enables the QMP monitor on localhost port 4444 with pretty-printing. 4354ERST 4355 4356DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4357 "-debugcon dev redirect the debug console to char device 'dev'\n", 4358 QEMU_ARCH_ALL) 4359SRST 4360``-debugcon dev`` 4361 Redirect the debug console to host device dev (same devices as the 4362 serial port). The debug console is an I/O port which is typically 4363 port 0xe9; writing to that I/O port sends output to this device. The 4364 default device is ``vc`` in graphical mode and ``stdio`` in non 4365 graphical mode. 4366ERST 4367 4368DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4369 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4370SRST 4371``-pidfile file`` 4372 Store the QEMU process PID in file. It is useful if you launch QEMU 4373 from a script. 4374ERST 4375 4376DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4377 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4378 QEMU_ARCH_ALL) 4379SRST 4380``--preconfig`` 4381 Pause QEMU for interactive configuration before the machine is 4382 created, which allows querying and configuring properties that will 4383 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4384 exit the preconfig state and move to the next state (i.e. run guest 4385 if -S isn't used or pause the second time if -S is used). This 4386 option is experimental. 4387ERST 4388 4389DEF("S", 0, QEMU_OPTION_S, \ 4390 "-S freeze CPU at startup (use 'c' to start execution)\n", 4391 QEMU_ARCH_ALL) 4392SRST 4393``-S`` 4394 Do not start CPU at startup (you must type 'c' in the monitor). 4395ERST 4396 4397DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4398 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4399 " run qemu with overcommit hints\n" 4400 " mem-lock=on|off controls memory lock support (default: off)\n" 4401 " cpu-pm=on|off controls cpu power management (default: off)\n", 4402 QEMU_ARCH_ALL) 4403SRST 4404``-overcommit mem-lock=on|off`` 4405 \ 4406``-overcommit cpu-pm=on|off`` 4407 Run qemu with hints about host resource overcommit. The default is 4408 to assume that host overcommits all resources. 4409 4410 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4411 (disabled by default). This works when host memory is not 4412 overcommitted and reduces the worst-case latency for guest. 4413 4414 Guest ability to manage power state of host cpus (increasing latency 4415 for other processes on the same host cpu, but decreasing latency for 4416 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4417 works best when host CPU is not overcommitted. When used, host 4418 estimates of CPU cycle and power utilization will be incorrect, not 4419 taking into account guest idle time. 4420ERST 4421 4422DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4423 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4424 " the guest without waiting for gdb to connect; use -S too\n" 4425 " if you want it to not start execution.)\n", 4426 QEMU_ARCH_ALL) 4427SRST 4428``-gdb dev`` 4429 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4430 in the System Emulation Users Guide). Note that this option does not pause QEMU 4431 execution -- if you want QEMU to not start the guest until you 4432 connect with gdb and issue a ``continue`` command, you will need to 4433 also pass the ``-S`` option to QEMU. 4434 4435 The most usual configuration is to listen on a local TCP socket:: 4436 4437 -gdb tcp::3117 4438 4439 but you can specify other backends; UDP, pseudo TTY, or even stdio 4440 are all reasonable use cases. For example, a stdio connection 4441 allows you to start QEMU from within gdb and establish the 4442 connection via a pipe: 4443 4444 .. parsed-literal:: 4445 4446 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4447ERST 4448 4449DEF("s", 0, QEMU_OPTION_s, \ 4450 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4451 QEMU_ARCH_ALL) 4452SRST 4453``-s`` 4454 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4455 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4456ERST 4457 4458DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4459 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4460 QEMU_ARCH_ALL) 4461SRST 4462``-d item1[,...]`` 4463 Enable logging of specified items. Use '-d help' for a list of log 4464 items. 4465ERST 4466 4467DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4468 "-D logfile output log to logfile (default stderr)\n", 4469 QEMU_ARCH_ALL) 4470SRST 4471``-D logfile`` 4472 Output log in logfile instead of to stderr 4473ERST 4474 4475DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4476 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4477 QEMU_ARCH_ALL) 4478SRST 4479``-dfilter range1[,...]`` 4480 Filter debug output to that relevant to a range of target addresses. 4481 The filter spec can be either start+size, start-size or start..end 4482 where start end and size are the addresses and sizes required. For 4483 example: 4484 4485 :: 4486 4487 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4488 4489 Will dump output for any code in the 0x1000 sized block starting at 4490 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4491 another 0x1000 sized block starting at 0xffffffc00005f000. 4492ERST 4493 4494DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4495 "-seed number seed the pseudo-random number generator\n", 4496 QEMU_ARCH_ALL) 4497SRST 4498``-seed number`` 4499 Force the guest to use a deterministic pseudo-random number 4500 generator, seeded with number. This does not affect crypto routines 4501 within the host. 4502ERST 4503 4504DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4505 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4506 QEMU_ARCH_ALL) 4507SRST 4508``-L path`` 4509 Set the directory for the BIOS, VGA BIOS and keymaps. 4510 4511 To list all the data directories, use ``-L help``. 4512ERST 4513 4514DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4515 "-enable-kvm enable KVM full virtualization support\n", 4516 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4517 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4518SRST 4519``-enable-kvm`` 4520 Enable KVM full virtualization support. This option is only 4521 available if KVM support is enabled when compiling. 4522ERST 4523 4524DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4525 "-xen-domid id specify xen guest domain id\n", 4526 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4527DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4528 "-xen-attach attach to existing xen domain\n" 4529 " libxl will use this when starting QEMU\n", 4530 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4531DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4532 "-xen-domid-restrict restrict set of available xen operations\n" 4533 " to specified domain id. (Does not affect\n" 4534 " xenpv machine type).\n", 4535 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4536SRST 4537``-xen-domid id`` 4538 Specify xen guest domain id (XEN only). 4539 4540``-xen-attach`` 4541 Attach to existing xen domain. libxl will use this when starting 4542 QEMU (XEN only). Restrict set of available xen operations to 4543 specified domain id (XEN only). 4544ERST 4545 4546DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4547 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4548SRST 4549``-no-reboot`` 4550 Exit instead of rebooting. 4551ERST 4552 4553DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4554 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4555SRST 4556``-no-shutdown`` 4557 Don't exit QEMU on guest shutdown, but instead only stop the 4558 emulation. This allows for instance switching to monitor to commit 4559 changes to the disk image. 4560ERST 4561 4562DEF("action", HAS_ARG, QEMU_OPTION_action, 4563 "-action reboot=reset|shutdown\n" 4564 " action when guest reboots [default=reset]\n" 4565 "-action shutdown=poweroff|pause\n" 4566 " action when guest shuts down [default=poweroff]\n" 4567 "-action panic=pause|shutdown|exit-failure|none\n" 4568 " action when guest panics [default=shutdown]\n" 4569 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4570 " action when watchdog fires [default=reset]\n", 4571 QEMU_ARCH_ALL) 4572SRST 4573``-action event=action`` 4574 The action parameter serves to modify QEMU's default behavior when 4575 certain guest events occur. It provides a generic method for specifying the 4576 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4577 parameters. 4578 4579 Examples: 4580 4581 ``-action panic=none`` 4582 ``-action reboot=shutdown,shutdown=pause`` 4583 ``-device i6300esb -action watchdog=pause`` 4584 4585ERST 4586 4587DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4588 "-loadvm [tag|id]\n" \ 4589 " start right away with a saved state (loadvm in monitor)\n", 4590 QEMU_ARCH_ALL) 4591SRST 4592``-loadvm file`` 4593 Start right away with a saved state (``loadvm`` in monitor) 4594ERST 4595 4596#ifndef _WIN32 4597DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4598 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4599#endif 4600SRST 4601``-daemonize`` 4602 Daemonize the QEMU process after initialization. QEMU will not 4603 detach from standard IO until it is ready to receive connections on 4604 any of its devices. This option is a useful way for external 4605 programs to launch QEMU without having to cope with initialization 4606 race conditions. 4607ERST 4608 4609DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4610 "-option-rom rom load a file, rom, into the option ROM space\n", 4611 QEMU_ARCH_ALL) 4612SRST 4613``-option-rom file`` 4614 Load the contents of file as an option ROM. This option is useful to 4615 load things like EtherBoot. 4616ERST 4617 4618DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4619 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4620 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4621 QEMU_ARCH_ALL) 4622 4623SRST 4624``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4625 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4626 the current UTC or local time, respectively. ``localtime`` is 4627 required for correct date in MS-DOS or Windows. To start at a 4628 specific point in time, provide datetime in the format 4629 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4630 4631 By default the RTC is driven by the host system time. This allows 4632 using of the RTC as accurate reference clock inside the guest, 4633 specifically if the host time is smoothly following an accurate 4634 external reference clock, e.g. via NTP. If you want to isolate the 4635 guest time from the host, you can set ``clock`` to ``rt`` instead, 4636 which provides a host monotonic clock if host support it. To even 4637 prevent the RTC from progressing during suspension, you can set 4638 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4639 recommended especially in icount mode in order to preserve 4640 determinism; however, note that in icount mode the speed of the 4641 virtual clock is variable and can in general differ from the host 4642 clock. 4643 4644 Enable ``driftfix`` (i386 targets only) if you experience time drift 4645 problems, specifically with Windows' ACPI HAL. This option will try 4646 to figure out how many timer interrupts were not processed by the 4647 Windows guest and will re-inject them. 4648ERST 4649 4650DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4651 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4652 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4653 " instruction, enable aligning the host and virtual clocks\n" \ 4654 " or disable real time cpu sleeping, and optionally enable\n" \ 4655 " record-and-replay mode\n", QEMU_ARCH_ALL) 4656SRST 4657``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4658 Enable virtual instruction counter. The virtual cpu will execute one 4659 instruction every 2^N ns of virtual time. If ``auto`` is specified 4660 then the virtual cpu speed will be automatically adjusted to keep 4661 virtual time within a few seconds of real time. 4662 4663 Note that while this option can give deterministic behavior, it does 4664 not provide cycle accurate emulation. Modern CPUs contain 4665 superscalar out of order cores with complex cache hierarchies. The 4666 number of instructions executed often has little or no correlation 4667 with actual performance. 4668 4669 When the virtual cpu is sleeping, the virtual time will advance at 4670 default speed unless ``sleep=on`` is specified. With 4671 ``sleep=on``, the virtual time will jump to the next timer 4672 deadline instantly whenever the virtual cpu goes to sleep mode and 4673 will not advance if no timer is enabled. This behavior gives 4674 deterministic execution times from the guest point of view. 4675 The default if icount is enabled is ``sleep=off``. 4676 ``sleep=on`` cannot be used together with either ``shift=auto`` 4677 or ``align=on``. 4678 4679 ``align=on`` will activate the delay algorithm which will try to 4680 synchronise the host clock and the virtual clock. The goal is to 4681 have a guest running at the real frequency imposed by the shift 4682 option. Whenever the guest clock is behind the host clock and if 4683 ``align=on`` is specified then we print a message to the user to 4684 inform about the delay. Currently this option does not work when 4685 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4686 shift values for which the guest clock runs ahead of the host clock. 4687 Typically this happens when the shift value is high (how high 4688 depends on the host machine). The default if icount is enabled 4689 is ``align=off``. 4690 4691 When the ``rr`` option is specified deterministic record/replay is 4692 enabled. The ``rrfile=`` option must also be provided to 4693 specify the path to the replay log. In record mode data is written 4694 to this file, and in replay mode it is read back. 4695 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4696 name. In record mode, a new VM snapshot with the given name is created 4697 at the start of execution recording. In replay mode this option 4698 specifies the snapshot name used to load the initial VM state. 4699ERST 4700 4701DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4702 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4703 " action when watchdog fires [default=reset]\n", 4704 QEMU_ARCH_ALL) 4705SRST 4706``-watchdog-action action`` 4707 The action controls what QEMU will do when the watchdog timer 4708 expires. The default is ``reset`` (forcefully reset the guest). 4709 Other possible actions are: ``shutdown`` (attempt to gracefully 4710 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4711 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4712 guest), ``debug`` (print a debug message and continue), or ``none`` 4713 (do nothing). 4714 4715 Note that the ``shutdown`` action requires that the guest responds 4716 to ACPI signals, which it may not be able to do in the sort of 4717 situations where the watchdog would have expired, and thus 4718 ``-watchdog-action shutdown`` is not recommended for production use. 4719 4720 Examples: 4721 4722 ``-device i6300esb -watchdog-action pause`` 4723 4724ERST 4725 4726DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4727 "-echr chr set terminal escape character instead of ctrl-a\n", 4728 QEMU_ARCH_ALL) 4729SRST 4730``-echr numeric_ascii_value`` 4731 Change the escape character used for switching to the monitor when 4732 using monitor and serial sharing. The default is ``0x01`` when using 4733 the ``-nographic`` option. ``0x01`` is equal to pressing 4734 ``Control-a``. You can select a different character from the ascii 4735 control keys where 1 through 26 map to Control-a through Control-z. 4736 For instance you could use the either of the following to change the 4737 escape character to Control-t. 4738 4739 ``-echr 0x14``; \ ``-echr 20`` 4740 4741ERST 4742 4743DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4744 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4745 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4746 "-incoming unix:socketpath\n" \ 4747 " prepare for incoming migration, listen on\n" \ 4748 " specified protocol and socket address\n" \ 4749 "-incoming fd:fd\n" \ 4750 "-incoming file:filename[,offset=offset]\n" \ 4751 "-incoming exec:cmdline\n" \ 4752 " accept incoming migration on given file descriptor\n" \ 4753 " or from given external command\n" \ 4754 "-incoming defer\n" \ 4755 " wait for the URI to be specified via migrate_incoming\n", 4756 QEMU_ARCH_ALL) 4757SRST 4758``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4759 \ 4760``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4761 Prepare for incoming migration, listen on a given tcp port. 4762 4763``-incoming unix:socketpath`` 4764 Prepare for incoming migration, listen on a given unix socket. 4765 4766``-incoming fd:fd`` 4767 Accept incoming migration from a given file descriptor. 4768 4769``-incoming file:filename[,offset=offset]`` 4770 Accept incoming migration from a given file starting at offset. 4771 offset allows the common size suffixes, or a 0x prefix, but not both. 4772 4773``-incoming exec:cmdline`` 4774 Accept incoming migration as an output from specified external 4775 command. 4776 4777``-incoming defer`` 4778 Wait for the URI to be specified via migrate\_incoming. The monitor 4779 can be used to change settings (such as migration parameters) prior 4780 to issuing the migrate\_incoming to allow the migration to begin. 4781ERST 4782 4783DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4784 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4785SRST 4786``-only-migratable`` 4787 Only allow migratable devices. Devices will not be allowed to enter 4788 an unmigratable state. 4789ERST 4790 4791DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4792 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4793SRST 4794``-nodefaults`` 4795 Don't create default devices. Normally, QEMU sets the default 4796 devices like serial port, parallel port, virtual console, monitor 4797 device, VGA adapter, floppy and CD-ROM drive and others. The 4798 ``-nodefaults`` option will disable all those default devices. 4799ERST 4800 4801#ifndef _WIN32 4802DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4803 "-runas user change to user id user just before starting the VM\n" \ 4804 " user can be numeric uid:gid instead\n", 4805 QEMU_ARCH_ALL) 4806#endif 4807SRST 4808``-runas user`` 4809 Immediately before starting guest execution, drop root privileges, 4810 switching to the specified user. 4811ERST 4812 4813DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4814 "-prom-env variable=value\n" 4815 " set OpenBIOS nvram variables\n", 4816 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4817SRST 4818``-prom-env variable=value`` 4819 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4820 4821 :: 4822 4823 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4824 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4825 4826 :: 4827 4828 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4829 -prom-env 'boot-device=hd:2,\yaboot' \ 4830 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4831ERST 4832DEF("semihosting", 0, QEMU_OPTION_semihosting, 4833 "-semihosting semihosting mode\n", 4834 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4835 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4836SRST 4837``-semihosting`` 4838 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4839 4840 .. warning:: 4841 Note that this allows guest direct access to the host filesystem, so 4842 should only be used with a trusted guest OS. 4843 4844 See the -semihosting-config option documentation for further 4845 information about the facilities this enables. 4846ERST 4847DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4848 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4849 " semihosting configuration\n", 4850QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4851QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4852SRST 4853``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4854 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4855 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 ``target=native|gdb|auto`` 4862 Defines where the semihosting calls will be addressed, to QEMU 4863 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4864 means ``gdb`` during debug sessions and ``native`` otherwise. 4865 4866 ``chardev=str1`` 4867 Send the output to a chardev backend output for native or auto 4868 output when not in gdb 4869 4870 ``userspace=on|off`` 4871 Allows code running in guest userspace to access the semihosting 4872 interface. The default is that only privileged guest code can 4873 make semihosting calls. Note that setting ``userspace=on`` should 4874 only be used if all guest code is trusted (for example, in 4875 bare-metal test case code). 4876 4877 ``arg=str1,arg=str2,...`` 4878 Allows the user to pass input arguments, and can be used 4879 multiple times to build up a list. The old-style 4880 ``-kernel``/``-append`` method of passing a command line is 4881 still supported for backward compatibility. If both the 4882 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4883 specified, the former is passed to semihosting as it always 4884 takes precedence. 4885ERST 4886DEF("old-param", 0, QEMU_OPTION_old_param, 4887 "-old-param old param mode\n", QEMU_ARCH_ARM) 4888SRST 4889``-old-param`` 4890 Old param mode (ARM only). 4891ERST 4892 4893DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4894 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4895 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4896 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4897 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4898 " by the kernel, but typically no longer used by modern\n" \ 4899 " C library implementations.\n" \ 4900 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4901 " to elevate privileges using set*uid|gid system calls.\n" \ 4902 " The value 'children' will deny set*uid|gid system calls for\n" \ 4903 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4904 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4905 " blocking *fork and execve\n" \ 4906 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4907 QEMU_ARCH_ALL) 4908SRST 4909``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4910 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4911 filtering and 'off' will disable it. The default is 'off'. 4912 4913 ``obsolete=string`` 4914 Enable Obsolete system calls 4915 4916 ``elevateprivileges=string`` 4917 Disable set\*uid\|gid system calls 4918 4919 ``spawn=string`` 4920 Disable \*fork and execve 4921 4922 ``resourcecontrol=string`` 4923 Disable process affinity and schedular priority 4924ERST 4925 4926DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4927 "-readconfig <file>\n" 4928 " read config file\n", QEMU_ARCH_ALL) 4929SRST 4930``-readconfig file`` 4931 Read device configuration from file. This approach is useful when 4932 you want to spawn QEMU process with many command line options but 4933 you don't want to exceed the command line character limit. 4934ERST 4935 4936DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4937 "-no-user-config\n" 4938 " do not load default user-provided config files at startup\n", 4939 QEMU_ARCH_ALL) 4940SRST 4941``-no-user-config`` 4942 The ``-no-user-config`` option makes QEMU not load any of the 4943 user-provided config files on sysconfdir. 4944ERST 4945 4946DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4947 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4948 " specify tracing options\n", 4949 QEMU_ARCH_ALL) 4950SRST 4951``-trace [[enable=]pattern][,events=file][,file=file]`` 4952 .. include:: ../qemu-option-trace.rst.inc 4953 4954ERST 4955DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4956 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4957 " load a plugin\n", 4958 QEMU_ARCH_ALL) 4959SRST 4960``-plugin file=file[,argname=argvalue]`` 4961 Load a plugin. 4962 4963 ``file=file`` 4964 Load the given plugin from a shared library file. 4965 4966 ``argname=argvalue`` 4967 Argument passed to the plugin. (Can be given multiple times.) 4968ERST 4969 4970HXCOMM Internal use 4971DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4972DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4973 4974#ifdef CONFIG_POSIX 4975DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4976 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4977 " Set miscellaneous QEMU process lifecycle options:\n" 4978 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4979 " chroot=dir chroot to dir just before starting the VM\n", 4980 QEMU_ARCH_ALL) 4981SRST 4982``-run-with [async-teardown=on|off][,chroot=dir]`` 4983 Set QEMU process lifecycle options. 4984 4985 ``async-teardown=on`` enables asynchronous teardown. A new process called 4986 "cleanup/<QEMU_PID>" will be created at startup sharing the address 4987 space with the main QEMU process, using clone. It will wait for the 4988 main QEMU process to terminate completely, and then exit. This allows 4989 QEMU to terminate very quickly even if the guest was huge, leaving the 4990 teardown of the address space to the cleanup process. Since the cleanup 4991 process shares the same cgroups as the main QEMU process, accounting is 4992 performed correctly. This only works if the cleanup process is not 4993 forcefully killed with SIGKILL before the main QEMU process has 4994 terminated completely. 4995 4996 ``chroot=dir`` can be used for doing a chroot to the specified directory 4997 immediately before starting the guest execution. This is especially useful 4998 in combination with -runas. 4999ERST 5000#endif 5001 5002DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5003 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5004 " control error message format\n" 5005 " timestamp=on enables timestamps (default: off)\n" 5006 " guest-name=on enables guest name prefix but only if\n" 5007 " -name guest option is set (default: off)\n", 5008 QEMU_ARCH_ALL) 5009SRST 5010``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5011 Control error message format. 5012 5013 ``timestamp=on|off`` 5014 Prefix messages with a timestamp. Default is off. 5015 5016 ``guest-name=on|off`` 5017 Prefix messages with guest name but only if -name guest option is set 5018 otherwise the option is ignored. Default is off. 5019ERST 5020 5021DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5022 "-dump-vmstate <file>\n" 5023 " Output vmstate information in JSON format to file.\n" 5024 " Use the scripts/vmstate-static-checker.py file to\n" 5025 " check for possible regressions in migration code\n" 5026 " by comparing two such vmstate dumps.\n", 5027 QEMU_ARCH_ALL) 5028SRST 5029``-dump-vmstate file`` 5030 Dump json-encoded vmstate information for current machine type to 5031 file in file 5032ERST 5033 5034DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5035 "-enable-sync-profile\n" 5036 " enable synchronization profiling\n", 5037 QEMU_ARCH_ALL) 5038SRST 5039``-enable-sync-profile`` 5040 Enable synchronization profiling. 5041ERST 5042 5043#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5044DEF("perfmap", 0, QEMU_OPTION_perfmap, 5045 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5046 QEMU_ARCH_ALL) 5047SRST 5048``-perfmap`` 5049 Generate a map file for Linux perf tools that will allow basic profiling 5050 information to be broken down into basic blocks. 5051ERST 5052 5053DEF("jitdump", 0, QEMU_OPTION_jitdump, 5054 "-jitdump generate a jit-${pid}.dump file for perf\n", 5055 QEMU_ARCH_ALL) 5056SRST 5057``-jitdump`` 5058 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5059 names, line numbers and JITted code. 5060ERST 5061#endif 5062 5063DEFHEADING() 5064 5065DEFHEADING(Generic object creation:) 5066 5067DEF("object", HAS_ARG, QEMU_OPTION_object, 5068 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5069 " create a new object of type TYPENAME setting properties\n" 5070 " in the order they are specified. Note that the 'id'\n" 5071 " property must be set. These objects are placed in the\n" 5072 " '/objects' path.\n", 5073 QEMU_ARCH_ALL) 5074SRST 5075``-object typename[,prop1=value1,...]`` 5076 Create a new object of type typename setting properties in the order 5077 they are specified. Note that the 'id' property must be set. These 5078 objects are placed in the '/objects' path. 5079 5080 ``-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`` 5081 Creates a memory file backend object, which can be used to back 5082 the guest RAM with huge pages. 5083 5084 The ``id`` parameter is a unique ID that will be used to 5085 reference this memory region in other parameters, e.g. ``-numa``, 5086 ``-device nvdimm``, etc. 5087 5088 The ``size`` option provides the size of the memory region, and 5089 accepts common suffixes, e.g. ``500M``. 5090 5091 The ``mem-path`` provides the path to either a shared memory or 5092 huge page filesystem mount. 5093 5094 The ``share`` boolean option determines whether the memory 5095 region is marked as private to QEMU, or shared. The latter 5096 allows a co-operating external process to access the QEMU memory 5097 region. 5098 5099 The ``share`` is also required for pvrdma devices due to 5100 limitations in the RDMA API provided by Linux. 5101 5102 Setting share=on might affect the ability to configure NUMA 5103 bindings for the memory backend under some circumstances, see 5104 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5105 source tree for additional details. 5106 5107 Setting the ``discard-data`` boolean option to on indicates that 5108 file contents can be destroyed when QEMU exits, to avoid 5109 unnecessarily flushing data to the backing file. Note that 5110 ``discard-data`` is only an optimization, and QEMU might not 5111 discard file contents if it aborts unexpectedly or is terminated 5112 using SIGKILL. 5113 5114 The ``merge`` boolean option enables memory merge, also known as 5115 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5116 the pages for memory deduplication. 5117 5118 Setting the ``dump`` boolean option to off excludes the memory 5119 from core dumps. This feature is also known as MADV\_DONTDUMP. 5120 5121 The ``prealloc`` boolean option enables memory preallocation. 5122 5123 The ``host-nodes`` option binds the memory range to a list of 5124 NUMA host nodes. 5125 5126 The ``policy`` option sets the NUMA policy to one of the 5127 following values: 5128 5129 ``default`` 5130 default host policy 5131 5132 ``preferred`` 5133 prefer the given host node list for allocation 5134 5135 ``bind`` 5136 restrict memory allocation to the given host node list 5137 5138 ``interleave`` 5139 interleave memory allocations across the given host node 5140 list 5141 5142 The ``align`` option specifies the base address alignment when 5143 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5144 ``2M``. Some backend store specified by ``mem-path`` requires an 5145 alignment different than the default one used by QEMU, eg the 5146 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5147 such cases, users can specify the required alignment via this 5148 option. 5149 5150 The ``offset`` option specifies the offset into the target file 5151 that the region starts at. You can use this parameter to back 5152 multiple regions with a single file. 5153 5154 The ``pmem`` option specifies whether the backing file specified 5155 by ``mem-path`` is in host persistent memory that can be 5156 accessed using the SNIA NVM programming model (e.g. Intel 5157 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5158 operations to guarantee the persistence of its own writes to 5159 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5160 migration). Also, we will map the backend-file with MAP\_SYNC 5161 flag, which ensures the file metadata is in sync for 5162 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5163 requires support from both the host kernel (since Linux kernel 5164 4.15) and the filesystem of ``mem-path`` mounted with DAX 5165 option. 5166 5167 The ``readonly`` option specifies whether the backing file is opened 5168 read-only or read-write (default). 5169 5170 The ``rom`` option specifies whether to create Read Only Memory 5171 (ROM) that cannot be modified by the VM. Any write attempts to such 5172 ROM will be denied. Most use cases want proper RAM instead of ROM. 5173 However, selected use cases, like R/O NVDIMMs, can benefit from 5174 ROM. If set to ``on``, create ROM; if set to ``off``, create 5175 writable RAM; if set to ``auto`` (default), the value of the 5176 ``readonly`` option is used. This option is primarily helpful when 5177 we want to have writable RAM in configurations that would 5178 traditionally create ROM before the ``rom`` option was introduced: 5179 VM templating, where we want to open a file readonly 5180 (``readonly=on``) and mark the memory to be private for QEMU 5181 (``share=off``). For this use case, we need writable RAM instead 5182 of ROM, and want to also set ``rom=off``. 5183 5184 ``-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`` 5185 Creates a memory backend object, which can be used to back the 5186 guest RAM. Memory backend objects offer more control than the 5187 ``-m`` option that is traditionally used to define guest RAM. 5188 Please refer to ``memory-backend-file`` for a description of the 5189 options. 5190 5191 ``-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`` 5192 Creates an anonymous memory file backend object, which allows 5193 QEMU to share the memory with an external process (e.g. when 5194 using vhost-user). The memory is allocated with memfd and 5195 optional sealing. (Linux only) 5196 5197 The ``seal`` option creates a sealed-file, that will block 5198 further resizing the memory ('on' by default). 5199 5200 The ``hugetlb`` option specify the file to be created resides in 5201 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5202 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5203 the hugetlb page size on systems that support multiple hugetlb 5204 page sizes (it must be a power of 2 value supported by the 5205 system). 5206 5207 In some versions of Linux, the ``hugetlb`` option is 5208 incompatible with the ``seal`` option (requires at least Linux 5209 4.16). 5210 5211 Please refer to ``memory-backend-file`` for a description of the 5212 other options. 5213 5214 The ``share`` boolean option is on by default with memfd. 5215 5216 ``-object iommufd,id=id[,fd=fd]`` 5217 Creates an iommufd backend which allows control of DMA mapping 5218 through the ``/dev/iommu`` device. 5219 5220 The ``id`` parameter is a unique ID which frontends (such as 5221 vfio-pci of vdpa) will use to connect with the iommufd backend. 5222 5223 The ``fd`` parameter is an optional pre-opened file descriptor 5224 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5225 across all subsystems, bringing the benefit of centralized 5226 reference counting. 5227 5228 ``-object rng-builtin,id=id`` 5229 Creates a random number generator backend which obtains entropy 5230 from QEMU builtin functions. The ``id`` parameter is a unique ID 5231 that will be used to reference this entropy backend from the 5232 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5233 uses this RNG backend. 5234 5235 ``-object rng-random,id=id,filename=/dev/random`` 5236 Creates a random number generator backend which obtains entropy 5237 from a device on the host. The ``id`` parameter is a unique ID 5238 that will be used to reference this entropy backend from the 5239 ``virtio-rng`` device. The ``filename`` parameter specifies 5240 which file to obtain entropy from and if omitted defaults to 5241 ``/dev/urandom``. 5242 5243 ``-object rng-egd,id=id,chardev=chardevid`` 5244 Creates a random number generator backend which obtains entropy 5245 from an external daemon running on the host. The ``id`` 5246 parameter is a unique ID that will be used to reference this 5247 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5248 parameter is the unique ID of a character device backend that 5249 provides the connection to the RNG daemon. 5250 5251 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5252 Creates a TLS anonymous credentials object, which can be used to 5253 provide TLS support on network backends. The ``id`` parameter is 5254 a unique ID which network backends will use to access the 5255 credentials. The ``endpoint`` is either ``server`` or ``client`` 5256 depending on whether the QEMU network backend that uses the 5257 credentials will be acting as a client or as a server. If 5258 ``verify-peer`` is enabled (the default) then once the handshake 5259 is completed, the peer credentials will be verified, though this 5260 is a no-op for anonymous credentials. 5261 5262 The dir parameter tells QEMU where to find the credential files. 5263 For server endpoints, this directory may contain a file 5264 dh-params.pem providing diffie-hellman parameters to use for the 5265 TLS server. If the file is missing, QEMU will generate a set of 5266 DH parameters at startup. This is a computationally expensive 5267 operation that consumes random pool entropy, so it is 5268 recommended that a persistent set of parameters be generated 5269 upfront and saved. 5270 5271 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5272 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5273 can be used to provide TLS support on network backends. The 5274 ``id`` parameter is a unique ID which network backends will use 5275 to access the credentials. The ``endpoint`` is either ``server`` 5276 or ``client`` depending on whether the QEMU network backend that 5277 uses the credentials will be acting as a client or as a server. 5278 For clients only, ``username`` is the username which will be 5279 sent to the server. If omitted it defaults to "qemu". 5280 5281 The dir parameter tells QEMU where to find the keys file. It is 5282 called "dir/keys.psk" and contains "username:key" pairs. This 5283 file can most easily be created using the GnuTLS ``psktool`` 5284 program. 5285 5286 For server endpoints, dir may also contain a file dh-params.pem 5287 providing diffie-hellman parameters to use for the TLS server. 5288 If the file is missing, QEMU will generate a set of DH 5289 parameters at startup. This is a computationally expensive 5290 operation that consumes random pool entropy, so it is 5291 recommended that a persistent set of parameters be generated up 5292 front and saved. 5293 5294 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5295 Creates a TLS anonymous credentials object, which can be used to 5296 provide TLS support on network backends. The ``id`` parameter is 5297 a unique ID which network backends will use to access the 5298 credentials. The ``endpoint`` is either ``server`` or ``client`` 5299 depending on whether the QEMU network backend that uses the 5300 credentials will be acting as a client or as a server. If 5301 ``verify-peer`` is enabled (the default) then once the handshake 5302 is completed, the peer credentials will be verified. With x509 5303 certificates, this implies that the clients must be provided 5304 with valid client certificates too. 5305 5306 The dir parameter tells QEMU where to find the credential files. 5307 For server endpoints, this directory may contain a file 5308 dh-params.pem providing diffie-hellman parameters to use for the 5309 TLS server. If the file is missing, QEMU will generate a set of 5310 DH parameters at startup. This is a computationally expensive 5311 operation that consumes random pool entropy, so it is 5312 recommended that a persistent set of parameters be generated 5313 upfront and saved. 5314 5315 For x509 certificate credentials the directory will contain 5316 further files providing the x509 certificates. The certificates 5317 must be stored in PEM format, in filenames ca-cert.pem, 5318 ca-crl.pem (optional), server-cert.pem (only servers), 5319 server-key.pem (only servers), client-cert.pem (only clients), 5320 and client-key.pem (only clients). 5321 5322 For the server-key.pem and client-key.pem files which contain 5323 sensitive private keys, it is possible to use an encrypted 5324 version by providing the passwordid parameter. This provides the 5325 ID of a previously created ``secret`` object containing the 5326 password for decryption. 5327 5328 The priority parameter allows to override the global default 5329 priority used by gnutls. This can be useful if the system 5330 administrator needs to use a weaker set of crypto priorities for 5331 QEMU without potentially forcing the weakness onto all 5332 applications. Or conversely if one wants wants a stronger 5333 default for QEMU than for all other applications, they can do 5334 this through this parameter. Its format is a gnutls priority 5335 string as described at 5336 https://gnutls.org/manual/html_node/Priority-Strings.html. 5337 5338 ``-object tls-cipher-suites,id=id,priority=priority`` 5339 Creates a TLS cipher suites object, which can be used to control 5340 the TLS cipher/protocol algorithms that applications are permitted 5341 to use. 5342 5343 The ``id`` parameter is a unique ID which frontends will use to 5344 access the ordered list of permitted TLS cipher suites from the 5345 host. 5346 5347 The ``priority`` parameter allows to override the global default 5348 priority used by gnutls. This can be useful if the system 5349 administrator needs to use a weaker set of crypto priorities for 5350 QEMU without potentially forcing the weakness onto all 5351 applications. Or conversely if one wants wants a stronger 5352 default for QEMU than for all other applications, they can do 5353 this through this parameter. Its format is a gnutls priority 5354 string as described at 5355 https://gnutls.org/manual/html_node/Priority-Strings.html. 5356 5357 An example of use of this object is to control UEFI HTTPS Boot. 5358 The tls-cipher-suites object exposes the ordered list of permitted 5359 TLS cipher suites from the host side to the guest firmware, via 5360 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5361 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5362 guest-side TLS. 5363 5364 In the following example, the priority at which the host-side policy 5365 is retrieved is given by the ``priority`` property. 5366 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5367 refer to /etc/crypto-policies/back-ends/gnutls.config. 5368 5369 .. parsed-literal:: 5370 5371 # |qemu_system| \\ 5372 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5373 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5374 5375 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5376 Interval t can't be 0, this filter batches the packet delivery: 5377 all packets arriving in a given interval on netdev netdevid are 5378 delayed until the end of the interval. Interval is in 5379 microseconds. ``status`` is optional that indicate whether the 5380 netfilter is on (enabled) or off (disabled), the default status 5381 for netfilter will be 'on'. 5382 5383 queue all\|rx\|tx is an option that can be applied to any 5384 netfilter. 5385 5386 ``all``: the filter is attached both to the receive and the 5387 transmit queue of the netdev (default). 5388 5389 ``rx``: the filter is attached to the receive queue of the 5390 netdev, where it will receive packets sent to the netdev. 5391 5392 ``tx``: the filter is attached to the transmit queue of the 5393 netdev, where it will receive packets sent by the netdev. 5394 5395 position head\|tail\|id=<id> is an option to specify where the 5396 filter should be inserted in the filter list. It can be applied 5397 to any netfilter. 5398 5399 ``head``: the filter is inserted at the head of the filter list, 5400 before any existing filters. 5401 5402 ``tail``: the filter is inserted at the tail of the filter list, 5403 behind any existing filters (default). 5404 5405 ``id=<id>``: the filter is inserted before or behind the filter 5406 specified by <id>, see the insert option below. 5407 5408 insert behind\|before is an option to specify where to insert 5409 the new filter relative to the one specified with 5410 position=id=<id>. It can be applied to any netfilter. 5411 5412 ``before``: insert before the specified filter. 5413 5414 ``behind``: insert behind the specified filter (default). 5415 5416 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5417 filter-mirror on netdev netdevid,mirror net packet to 5418 chardevchardevid, if it has the vnet\_hdr\_support flag, 5419 filter-mirror will mirror packet with vnet\_hdr\_len. 5420 5421 ``-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]`` 5422 filter-redirector on netdev netdevid,redirect filter's net 5423 packet to chardev chardevid,and redirect indev's packet to 5424 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5425 will redirect packet with vnet\_hdr\_len. Create a 5426 filter-redirector we need to differ outdev id from indev id, id 5427 can not be the same. we can just use indev or outdev, but at 5428 least one of indev or outdev need to be specified. 5429 5430 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5431 Filter-rewriter is a part of COLO project.It will rewrite tcp 5432 packet to secondary from primary to keep secondary tcp 5433 connection,and rewrite tcp packet to primary from secondary make 5434 tcp packet can be handled by client.if it has the 5435 vnet\_hdr\_support flag, we can parse packet with vnet header. 5436 5437 usage: colo secondary: -object 5438 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5439 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5440 filter-rewriter,id=rew0,netdev=hn0,queue=all 5441 5442 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5443 Dump the network traffic on netdev dev to the file specified by 5444 filename. At most len bytes (64k by default) per packet are 5445 stored. The file format is libpcap, so it can be analyzed with 5446 tools such as tcpdump or Wireshark. 5447 5448 ``-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}]`` 5449 Colo-compare gets packet from primary\_in chardevid and 5450 secondary\_in, then compare whether the payload of primary packet 5451 and secondary packet are the same. If same, it will output 5452 primary packet to out\_dev, else it will notify COLO-framework to do 5453 checkpoint and send primary packet to out\_dev. In order to 5454 improve efficiency, we need to put the task of comparison in 5455 another iothread. If it has the vnet\_hdr\_support flag, 5456 colo compare will send/recv packet with vnet\_hdr\_len. 5457 The compare\_timeout=@var{ms} determines the maximum time of the 5458 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5459 is to set the period of scanning expired primary node network packets. 5460 The max\_queue\_size=@var{size} is to set the max compare queue 5461 size depend on user environment. 5462 If user want to use Xen COLO, need to add the notify\_dev to 5463 notify Xen colo-frame to do checkpoint. 5464 5465 COLO-compare must be used with the help of filter-mirror, 5466 filter-redirector and filter-rewriter. 5467 5468 :: 5469 5470 KVM COLO 5471 5472 primary: 5473 -netdev tap,id=hn0,vhost=off 5474 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5475 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5476 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5477 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5478 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5479 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5480 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5481 -object iothread,id=iothread1 5482 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5483 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5484 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5485 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5486 5487 secondary: 5488 -netdev tap,id=hn0,vhost=off 5489 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5490 -chardev socket,id=red0,host=3.3.3.3,port=9003 5491 -chardev socket,id=red1,host=3.3.3.3,port=9004 5492 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5493 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5494 5495 5496 Xen COLO 5497 5498 primary: 5499 -netdev tap,id=hn0,vhost=off 5500 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5501 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5502 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5503 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5504 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5505 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5506 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5507 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5508 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5509 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5510 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5511 -object iothread,id=iothread1 5512 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5513 5514 secondary: 5515 -netdev tap,id=hn0,vhost=off 5516 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5517 -chardev socket,id=red0,host=3.3.3.3,port=9003 5518 -chardev socket,id=red1,host=3.3.3.3,port=9004 5519 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5520 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5521 5522 If you want to know the detail of above command line, you can 5523 read the colo-compare git log. 5524 5525 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5526 Creates a cryptodev backend which executes crypto operations from 5527 the QEMU cipher APIs. The id parameter is a unique ID that will 5528 be used to reference this cryptodev backend from the 5529 ``virtio-crypto`` device. The queues parameter is optional, 5530 which specify the queue number of cryptodev backend, the default 5531 of queues is 1. 5532 5533 .. parsed-literal:: 5534 5535 # |qemu_system| \\ 5536 [...] \\ 5537 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5538 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5539 [...] 5540 5541 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5542 Creates a vhost-user cryptodev backend, backed by a chardev 5543 chardevid. The id parameter is a unique ID that will be used to 5544 reference this cryptodev backend from the ``virtio-crypto`` 5545 device. The chardev should be a unix domain socket backed one. 5546 The vhost-user uses a specifically defined protocol to pass 5547 vhost ioctl replacement messages to an application on the other 5548 end of the socket. The queues parameter is optional, which 5549 specify the queue number of cryptodev backend for multiqueue 5550 vhost-user, the default of queues is 1. 5551 5552 .. parsed-literal:: 5553 5554 # |qemu_system| \\ 5555 [...] \\ 5556 -chardev socket,id=chardev0,path=/path/to/socket \\ 5557 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5558 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5559 [...] 5560 5561 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5562 \ 5563 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5564 Defines a secret to store a password, encryption key, or some 5565 other sensitive data. The sensitive data can either be passed 5566 directly via the data parameter, or indirectly via the file 5567 parameter. Using the data parameter is insecure unless the 5568 sensitive data is encrypted. 5569 5570 The sensitive data can be provided in raw format (the default), 5571 or base64. When encoded as JSON, the raw format only supports 5572 valid UTF-8 characters, so base64 is recommended for sending 5573 binary data. QEMU will convert from which ever format is 5574 provided to the format it needs internally. eg, an RBD password 5575 can be provided in raw format, even though it will be base64 5576 encoded when passed onto the RBD sever. 5577 5578 For added protection, it is possible to encrypt the data 5579 associated with a secret using the AES-256-CBC cipher. Use of 5580 encryption is indicated by providing the keyid and iv 5581 parameters. The keyid parameter provides the ID of a previously 5582 defined secret that contains the AES-256 decryption key. This 5583 key should be 32-bytes long and be base64 encoded. The iv 5584 parameter provides the random initialization vector used for 5585 encryption of this particular secret and should be a base64 5586 encrypted string of the 16-byte IV. 5587 5588 The simplest (insecure) usage is to provide the secret inline 5589 5590 .. parsed-literal:: 5591 5592 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5593 5594 The simplest secure usage is to provide the secret via a file 5595 5596 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5597 secret,id=sec0,file=mypasswd.txt,format=raw 5598 5599 For greater security, AES-256-CBC should be used. To illustrate 5600 usage, consider the openssl command line tool which can encrypt 5601 the data. Note that when encrypting, the plaintext must be 5602 padded to the cipher block size (32 bytes) using the standard 5603 PKCS#5/6 compatible padding algorithm. 5604 5605 First a master key needs to be created in base64 encoding: 5606 5607 :: 5608 5609 # openssl rand -base64 32 > key.b64 5610 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5611 5612 Each secret to be encrypted needs to have a random 5613 initialization vector generated. These do not need to be kept 5614 secret 5615 5616 :: 5617 5618 # openssl rand -base64 16 > iv.b64 5619 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5620 5621 The secret to be defined can now be encrypted, in this case 5622 we're telling openssl to base64 encode the result, but it could 5623 be left as raw bytes if desired. 5624 5625 :: 5626 5627 # SECRET=$(printf "letmein" | 5628 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5629 5630 When launching QEMU, create a master secret pointing to 5631 ``key.b64`` and specify that to be used to decrypt the user 5632 password. Pass the contents of ``iv.b64`` to the second secret 5633 5634 .. parsed-literal:: 5635 5636 # |qemu_system| \\ 5637 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5638 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5639 data=$SECRET,iv=$(<iv.b64) 5640 5641 ``-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]`` 5642 Create a Secure Encrypted Virtualization (SEV) guest object, 5643 which can be used to provide the guest memory encryption support 5644 on AMD processors. 5645 5646 When memory encryption is enabled, one of the physical address 5647 bit (aka the C-bit) is utilized to mark if a memory page is 5648 protected. The ``cbitpos`` is used to provide the C-bit 5649 position. The C-bit position is Host family dependent hence user 5650 must provide this value. On EPYC, the value should be 47. 5651 5652 When memory encryption is enabled, we loose certain bits in 5653 physical address space. The ``reduced-phys-bits`` is used to 5654 provide the number of bits we loose in physical address space. 5655 Similar to C-bit, the value is Host family dependent. On EPYC, 5656 a guest will lose a maximum of 1 bit, so the value should be 1. 5657 5658 The ``sev-device`` provides the device file to use for 5659 communicating with the SEV firmware running inside AMD Secure 5660 Processor. The default device is '/dev/sev'. If hardware 5661 supports memory encryption then /dev/sev devices are created by 5662 CCP driver. 5663 5664 The ``policy`` provides the guest policy to be enforced by the 5665 SEV firmware and restrict what configuration and operational 5666 commands can be performed on this guest by the hypervisor. The 5667 policy should be provided by the guest owner and is bound to the 5668 guest and cannot be changed throughout the lifetime of the 5669 guest. The default is 0. 5670 5671 If guest ``policy`` allows sharing the key with another SEV 5672 guest then ``handle`` can be use to provide handle of the guest 5673 from which to share the key. 5674 5675 The ``dh-cert-file`` and ``session-file`` provides the guest 5676 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5677 and session parameters are used for establishing a cryptographic 5678 session with the guest owner to negotiate keys used for 5679 attestation. The file must be encoded in base64. 5680 5681 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5682 cmdline to a designated guest firmware page for measured Linux 5683 boot with -kernel. The default is off. (Since 6.2) 5684 5685 e.g to launch a SEV guest 5686 5687 .. parsed-literal:: 5688 5689 # |qemu_system_x86| \\ 5690 ...... \\ 5691 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5692 -machine ...,memory-encryption=sev0 \\ 5693 ..... 5694 5695 ``-object authz-simple,id=id,identity=string`` 5696 Create an authorization object that will control access to 5697 network services. 5698 5699 The ``identity`` parameter is identifies the user and its format 5700 depends on the network service that authorization object is 5701 associated with. For authorizing based on TLS x509 certificates, 5702 the identity must be the x509 distinguished name. Note that care 5703 must be taken to escape any commas in the distinguished name. 5704 5705 An example authorization object to validate a x509 distinguished 5706 name would look like: 5707 5708 .. parsed-literal:: 5709 5710 # |qemu_system| \\ 5711 ... \\ 5712 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5713 ... 5714 5715 Note the use of quotes due to the x509 distinguished name 5716 containing whitespace, and escaping of ','. 5717 5718 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5719 Create an authorization object that will control access to 5720 network services. 5721 5722 The ``filename`` parameter is the fully qualified path to a file 5723 containing the access control list rules in JSON format. 5724 5725 An example set of rules that match against SASL usernames might 5726 look like: 5727 5728 :: 5729 5730 { 5731 "rules": [ 5732 { "match": "fred", "policy": "allow", "format": "exact" }, 5733 { "match": "bob", "policy": "allow", "format": "exact" }, 5734 { "match": "danb", "policy": "deny", "format": "glob" }, 5735 { "match": "dan*", "policy": "allow", "format": "exact" }, 5736 ], 5737 "policy": "deny" 5738 } 5739 5740 When checking access the object will iterate over all the rules 5741 and the first rule to match will have its ``policy`` value 5742 returned as the result. If no rules match, then the default 5743 ``policy`` value is returned. 5744 5745 The rules can either be an exact string match, or they can use 5746 the simple UNIX glob pattern matching to allow wildcards to be 5747 used. 5748 5749 If ``refresh`` is set to true the file will be monitored and 5750 automatically reloaded whenever its content changes. 5751 5752 As with the ``authz-simple`` object, the format of the identity 5753 strings being matched depends on the network service, but is 5754 usually a TLS x509 distinguished name, or a SASL username. 5755 5756 An example authorization object to validate a SASL username 5757 would look like: 5758 5759 .. parsed-literal:: 5760 5761 # |qemu_system| \\ 5762 ... \\ 5763 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5764 ... 5765 5766 ``-object authz-pam,id=id,service=string`` 5767 Create an authorization object that will control access to 5768 network services. 5769 5770 The ``service`` parameter provides the name of a PAM service to 5771 use for authorization. It requires that a file 5772 ``/etc/pam.d/service`` exist to provide the configuration for 5773 the ``account`` subsystem. 5774 5775 An example authorization object to validate a TLS x509 5776 distinguished name would look like: 5777 5778 .. parsed-literal:: 5779 5780 # |qemu_system| \\ 5781 ... \\ 5782 -object authz-pam,id=auth0,service=qemu-vnc \\ 5783 ... 5784 5785 There would then be a corresponding config file for PAM at 5786 ``/etc/pam.d/qemu-vnc`` that contains: 5787 5788 :: 5789 5790 account requisite pam_listfile.so item=user sense=allow \ 5791 file=/etc/qemu/vnc.allow 5792 5793 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5794 of x509 distinguished names that are permitted access 5795 5796 :: 5797 5798 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5799 5800 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5801 Creates a dedicated event loop thread that devices can be 5802 assigned to. This is known as an IOThread. By default device 5803 emulation happens in vCPU threads or the main event loop thread. 5804 This can become a scalability bottleneck. IOThreads allow device 5805 emulation and I/O to run on other host CPUs. 5806 5807 The ``id`` parameter is a unique ID that will be used to 5808 reference this IOThread from ``-device ...,iothread=id``. 5809 Multiple devices can be assigned to an IOThread. Note that not 5810 all devices support an ``iothread`` parameter. 5811 5812 The ``query-iothreads`` QMP command lists IOThreads and reports 5813 their thread IDs so that the user can configure host CPU 5814 pinning/affinity. 5815 5816 IOThreads use an adaptive polling algorithm to reduce event loop 5817 latency. Instead of entering a blocking system call to monitor 5818 file descriptors and then pay the cost of being woken up when an 5819 event occurs, the polling algorithm spins waiting for events for 5820 a short time. The algorithm's default parameters are suitable 5821 for many cases but can be adjusted based on knowledge of the 5822 workload and/or host device latency. 5823 5824 The ``poll-max-ns`` parameter is the maximum number of 5825 nanoseconds to busy wait for events. Polling can be disabled by 5826 setting this value to 0. 5827 5828 The ``poll-grow`` parameter is the multiplier used to increase 5829 the polling time when the algorithm detects it is missing events 5830 due to not polling long enough. 5831 5832 The ``poll-shrink`` parameter is the divisor used to decrease 5833 the polling time when the algorithm detects it is spending too 5834 long polling without encountering events. 5835 5836 The ``aio-max-batch`` parameter is the maximum number of requests 5837 in a batch for the AIO engine, 0 means that the engine will use 5838 its default. 5839 5840 The IOThread parameters can be modified at run-time using the 5841 ``qom-set`` command (where ``iothread1`` is the IOThread's 5842 ``id``): 5843 5844 :: 5845 5846 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5847ERST 5848 5849 5850HXCOMM This is the last statement. Insert new options before this line! 5851 5852#undef DEF 5853#undef DEFHEADING 5854#undef ARCHHEADING 5855
