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][,zoom-to-fit=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 originally 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). Synonym of ``-global 2645 ide-device.win2k-install-hack=on``. 2646ERST 2647 2648DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2649 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2650 QEMU_ARCH_I386) 2651SRST 2652``-no-fd-bootchk`` 2653 Disable boot signature checking for floppy disks in BIOS. May be 2654 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2655ERST 2656 2657DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2658 "-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" 2659 " ACPI table description\n", QEMU_ARCH_I386) 2660SRST 2661``-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]...]`` 2662 Add ACPI table with specified header fields and context from 2663 specified files. For file=, take whole ACPI table from the specified 2664 files, including all ACPI headers (possible overridden by other 2665 options). For data=, only data portion of the table is used, all 2666 header information is specified in the command line. If a SLIC table 2667 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2668 fields will override the same in the RSDT and the FADT (a.k.a. 2669 FACP), in order to ensure the field matches required by the 2670 Microsoft SLIC spec and the ACPI spec. 2671ERST 2672 2673DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2674 "-smbios file=binary\n" 2675 " load SMBIOS entry from binary file\n" 2676 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2677 " [,uefi=on|off]\n" 2678 " specify SMBIOS type 0 fields\n" 2679 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2680 " [,uuid=uuid][,sku=str][,family=str]\n" 2681 " specify SMBIOS type 1 fields\n" 2682 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2683 " [,asset=str][,location=str]\n" 2684 " specify SMBIOS type 2 fields\n" 2685 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2686 " [,sku=str]\n" 2687 " specify SMBIOS type 3 fields\n" 2688 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2689 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2690 " [,processor-family=%d,processor-id=%d]\n" 2691 " specify SMBIOS type 4 fields\n" 2692 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2693 " specify SMBIOS type 8 fields\n" 2694 "-smbios type=11[,value=str][,path=filename]\n" 2695 " specify SMBIOS type 11 fields\n" 2696 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2697 " [,asset=str][,part=str][,speed=%d]\n" 2698 " specify SMBIOS type 17 fields\n" 2699 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2700 " specify SMBIOS type 41 fields\n", 2701 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2702SRST 2703``-smbios file=binary`` 2704 Load SMBIOS entry from binary file. 2705 2706``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2707 Specify SMBIOS type 0 fields 2708 2709``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2710 Specify SMBIOS type 1 fields 2711 2712``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2713 Specify SMBIOS type 2 fields 2714 2715``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2716 Specify SMBIOS type 3 fields 2717 2718``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2719 Specify SMBIOS type 4 fields 2720 2721``-smbios type=9[,slot_designation=str][,slot_type=%d][,slot_data_bus_width=%d][,current_usage=%d][,slot_length=%d][,slot_id=%d][,slot_characteristics1=%d][,slot_characteristics12=%d][,pci_device=str]`` 2722 Specify SMBIOS type 9 fields 2723 2724``-smbios type=11[,value=str][,path=filename]`` 2725 Specify SMBIOS type 11 fields 2726 2727 This argument can be repeated multiple times, and values are added in the order they are parsed. 2728 Applications intending to use OEM strings data are encouraged to use their application name as 2729 a prefix for the value string. This facilitates passing information for multiple applications 2730 concurrently. 2731 2732 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2733 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2734 2735 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2736 the SMBIOS table in the order in which they appear. 2737 2738 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2739 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2740 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2741 data set, for example, by specifying the serial ID of a block device. 2742 2743 An example passing three strings is 2744 2745 .. parsed-literal:: 2746 2747 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2748 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2749 path=/some/file/with/oemstringsdata.txt 2750 2751 In the guest OS this is visible with the ``dmidecode`` command 2752 2753 .. parsed-literal:: 2754 2755 $ dmidecode -t 11 2756 Handle 0x0E00, DMI type 11, 5 bytes 2757 OEM Strings 2758 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2759 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2760 String 3: myapp:some extra data 2761 2762 2763``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2764 Specify SMBIOS type 17 fields 2765 2766``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2767 Specify SMBIOS type 41 fields 2768 2769 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2770 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2771 position on the PCI bus. 2772 2773 Here is an example of use: 2774 2775 .. parsed-literal:: 2776 2777 -netdev user,id=internet \\ 2778 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2779 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2780 2781 In the guest OS, the device should then appear as ``eno1``: 2782 2783 ..parsed-literal:: 2784 2785 $ ip -brief l 2786 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2787 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2788 2789 Currently, the PCI device has to be attached to the root bus. 2790 2791ERST 2792 2793DEFHEADING() 2794 2795DEFHEADING(Network options:) 2796 2797DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2798#ifdef CONFIG_SLIRP 2799 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2800 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2801 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2802 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2803 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2804#ifndef _WIN32 2805 "[,smb=dir[,smbserver=addr]]\n" 2806#endif 2807 " configure a user mode network backend with ID 'str',\n" 2808 " its DHCP server and optional services\n" 2809#endif 2810#ifdef _WIN32 2811 "-netdev tap,id=str,ifname=name\n" 2812 " configure a host TAP network backend with ID 'str'\n" 2813#else 2814 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2815 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2816 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2817 " [,poll-us=n]\n" 2818 " configure a host TAP network backend with ID 'str'\n" 2819 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2820 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2821 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2822 " to deconfigure it\n" 2823 " use '[down]script=no' to disable script execution\n" 2824 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2825 " configure it\n" 2826 " use 'fd=h' to connect to an already opened TAP interface\n" 2827 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2828 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2829 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2830 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2831 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2832 " use vhost=on to enable experimental in kernel accelerator\n" 2833 " (only has effect for virtio guests which use MSIX)\n" 2834 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2835 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2836 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2837 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2838 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2839 " spent on busy polling for vhost net\n" 2840 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2841 " configure a host TAP network backend with ID 'str' that is\n" 2842 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2843 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2844#endif 2845#ifdef __linux__ 2846 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2847 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2848 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2849 " [,rxcookie=rxcookie][,offset=offset]\n" 2850 " configure a network backend with ID 'str' connected to\n" 2851 " an Ethernet over L2TPv3 pseudowire.\n" 2852 " Linux kernel 3.3+ as well as most routers can talk\n" 2853 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2854 " VM to a router and even VM to Host. It is a nearly-universal\n" 2855 " standard (RFC3931). Note - this implementation uses static\n" 2856 " pre-configured tunnels (same as the Linux kernel).\n" 2857 " use 'src=' to specify source address\n" 2858 " use 'dst=' to specify destination address\n" 2859 " use 'udp=on' to specify udp encapsulation\n" 2860 " use 'srcport=' to specify source udp port\n" 2861 " use 'dstport=' to specify destination udp port\n" 2862 " use 'ipv6=on' to force v6\n" 2863 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2864 " well as a weak security measure\n" 2865 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2866 " use 'txcookie=0x012345678' to specify a txcookie\n" 2867 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2868 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2869 " use 'pincounter=on' to work around broken counter handling in peer\n" 2870 " use 'offset=X' to add an extra offset between header and data\n" 2871#endif 2872 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2873 " configure a network backend to connect to another network\n" 2874 " using a socket connection\n" 2875 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2876 " configure a network backend to connect to a multicast maddr and port\n" 2877 " use 'localaddr=addr' to specify the host address to send packets from\n" 2878 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2879 " configure a network backend to connect to another network\n" 2880 " using an UDP tunnel\n" 2881 "-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" 2882 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2883 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2884 " configure a network backend to connect to another network\n" 2885 " using a socket connection in stream mode.\n" 2886 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2887 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2888 " configure a network backend to connect to a multicast maddr and port\n" 2889 " use ``local.host=addr`` to specify the host address to send packets from\n" 2890 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2891 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2892 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2893 " configure a network backend to connect to another network\n" 2894 " using an UDP tunnel\n" 2895#ifdef CONFIG_VDE 2896 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2897 " configure a network backend to connect to port 'n' of a vde switch\n" 2898 " running on host and listening for incoming connections on 'socketpath'.\n" 2899 " Use group 'groupname' and mode 'octalmode' to change default\n" 2900 " ownership and permissions for communication port.\n" 2901#endif 2902#ifdef CONFIG_NETMAP 2903 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2904 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2905 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2906 " netmap device, defaults to '/dev/netmap')\n" 2907#endif 2908#ifdef CONFIG_AF_XDP 2909 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2910 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2911 " attach to the existing network interface 'name' with AF_XDP socket\n" 2912 " use 'mode=MODE' to specify an XDP program attach mode\n" 2913 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2914 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2915 " with inhibit=on,\n" 2916 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2917 " added to a socket map in XDP program. One socket per queue.\n" 2918 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2919 " use 'start-queue=m' to specify the first queue that should be used\n" 2920#endif 2921#ifdef CONFIG_POSIX 2922 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2923 " configure a vhost-user network, backed by a chardev 'dev'\n" 2924#endif 2925#ifdef __linux__ 2926 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2927 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2928 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2929 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2930#endif 2931#ifdef CONFIG_VMNET 2932 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2933 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2934 " configure a vmnet network backend in host mode with ID 'str',\n" 2935 " isolate this interface from others with 'isolated',\n" 2936 " configure the address range and choose a subnet mask,\n" 2937 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2938 " vmnet-host interfaces within this isolated network\n" 2939 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2940 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2941 " configure a vmnet network backend in shared mode with ID 'str',\n" 2942 " configure the address range and choose a subnet mask,\n" 2943 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2944 " isolate this interface from others with 'isolated'\n" 2945 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2946 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2947 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2948 " isolate this interface from others with 'isolated'\n" 2949#endif 2950 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2951 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2952DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2953 "-nic [tap|bridge|" 2954#ifdef CONFIG_SLIRP 2955 "user|" 2956#endif 2957#ifdef __linux__ 2958 "l2tpv3|" 2959#endif 2960#ifdef CONFIG_VDE 2961 "vde|" 2962#endif 2963#ifdef CONFIG_NETMAP 2964 "netmap|" 2965#endif 2966#ifdef CONFIG_AF_XDP 2967 "af-xdp|" 2968#endif 2969#ifdef CONFIG_POSIX 2970 "vhost-user|" 2971#endif 2972#ifdef CONFIG_VMNET 2973 "vmnet-host|vmnet-shared|vmnet-bridged|" 2974#endif 2975 "socket][,option][,...][mac=macaddr]\n" 2976 " initialize an on-board / default host NIC (using MAC address\n" 2977 " macaddr) and connect it to the given host network backend\n" 2978 "-nic none use it alone to have zero network devices (the default is to\n" 2979 " provided a 'user' network connection)\n", 2980 QEMU_ARCH_ALL) 2981DEF("net", HAS_ARG, QEMU_OPTION_net, 2982 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2983 " configure or create an on-board (or machine default) NIC and\n" 2984 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2985 "-net [" 2986#ifdef CONFIG_SLIRP 2987 "user|" 2988#endif 2989 "tap|" 2990 "bridge|" 2991#ifdef CONFIG_VDE 2992 "vde|" 2993#endif 2994#ifdef CONFIG_NETMAP 2995 "netmap|" 2996#endif 2997#ifdef CONFIG_AF_XDP 2998 "af-xdp|" 2999#endif 3000#ifdef CONFIG_VMNET 3001 "vmnet-host|vmnet-shared|vmnet-bridged|" 3002#endif 3003 "socket][,option][,option][,...]\n" 3004 " old way to initialize a host network interface\n" 3005 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3006SRST 3007``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3008 This option is a shortcut for configuring both the on-board 3009 (default) guest NIC hardware and the host network backend in one go. 3010 The host backend options are the same as with the corresponding 3011 ``-netdev`` options below. The guest NIC model can be set with 3012 ``model=modelname``. Use ``model=help`` to list the available device 3013 types. The hardware MAC address can be set with ``mac=macaddr``. 3014 3015 The following two example do exactly the same, to show how ``-nic`` 3016 can be used to shorten the command line length: 3017 3018 .. parsed-literal:: 3019 3020 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3021 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3022 3023``-nic none`` 3024 Indicate that no network devices should be configured. It is used to 3025 override the default configuration (default NIC with "user" host 3026 network backend) which is activated if no other networking options 3027 are provided. 3028 3029``-netdev user,id=id[,option][,option][,...]`` 3030 Configure user mode host network backend which requires no 3031 administrator privilege to run. Valid options are: 3032 3033 ``id=id`` 3034 Assign symbolic name for use in monitor commands. 3035 3036 ``ipv4=on|off and ipv6=on|off`` 3037 Specify that either IPv4 or IPv6 must be enabled. If neither is 3038 specified both protocols are enabled. 3039 3040 ``net=addr[/mask]`` 3041 Set IP network address the guest will see. Optionally specify 3042 the netmask, either in the form a.b.c.d or as number of valid 3043 top-most bits. Default is 10.0.2.0/24. 3044 3045 ``host=addr`` 3046 Specify the guest-visible address of the host. Default is the 3047 2nd IP in the guest network, i.e. x.x.x.2. 3048 3049 ``ipv6-net=addr[/int]`` 3050 Set IPv6 network address the guest will see (default is 3051 fec0::/64). The network prefix is given in the usual hexadecimal 3052 IPv6 address notation. The prefix size is optional, and is given 3053 as the number of valid top-most bits (default is 64). 3054 3055 ``ipv6-host=addr`` 3056 Specify the guest-visible IPv6 address of the host. Default is 3057 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3058 3059 ``restrict=on|off`` 3060 If this option is enabled, the guest will be isolated, i.e. it 3061 will not be able to contact the host and no guest IP packets 3062 will be routed over the host to the outside. This option does 3063 not affect any explicitly set forwarding rules. 3064 3065 ``hostname=name`` 3066 Specifies the client hostname reported by the built-in DHCP 3067 server. 3068 3069 ``dhcpstart=addr`` 3070 Specify the first of the 16 IPs the built-in DHCP server can 3071 assign. Default is the 15th to 31st IP in the guest network, 3072 i.e. x.x.x.15 to x.x.x.31. 3073 3074 ``dns=addr`` 3075 Specify the guest-visible address of the virtual nameserver. The 3076 address must be different from the host address. Default is the 3077 3rd IP in the guest network, i.e. x.x.x.3. 3078 3079 ``ipv6-dns=addr`` 3080 Specify the guest-visible address of the IPv6 virtual 3081 nameserver. The address must be different from the host address. 3082 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3083 3084 ``dnssearch=domain`` 3085 Provides an entry for the domain-search list sent by the 3086 built-in DHCP server. More than one domain suffix can be 3087 transmitted by specifying this option multiple times. If 3088 supported, this will cause the guest to automatically try to 3089 append the given domain suffix(es) in case a domain name can not 3090 be resolved. 3091 3092 Example: 3093 3094 .. parsed-literal:: 3095 3096 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3097 3098 ``domainname=domain`` 3099 Specifies the client domain name reported by the built-in DHCP 3100 server. 3101 3102 ``tftp=dir`` 3103 When using the user mode network stack, activate a built-in TFTP 3104 server. The files in dir will be exposed as the root of a TFTP 3105 server. The TFTP client on the guest must be configured in 3106 binary mode (use the command ``bin`` of the Unix TFTP client). 3107 The built-in TFTP server is read-only; it does not implement any 3108 command for writing files. QEMU will not write to this directory. 3109 3110 ``tftp-server-name=name`` 3111 In BOOTP reply, broadcast name as the "TFTP server name" 3112 (RFC2132 option 66). This can be used to advise the guest to 3113 load boot files or configurations from a different server than 3114 the host address. 3115 3116 ``bootfile=file`` 3117 When using the user mode network stack, broadcast file as the 3118 BOOTP filename. In conjunction with ``tftp``, this can be used 3119 to network boot a guest from a local directory. 3120 3121 Example (using pxelinux): 3122 3123 .. parsed-literal:: 3124 3125 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3126 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3127 3128 ``smb=dir[,smbserver=addr]`` 3129 When using the user mode network stack, activate a built-in SMB 3130 server so that Windows OSes can access to the host files in 3131 ``dir`` transparently. The IP address of the SMB server can be 3132 set to addr. By default the 4th IP in the guest network is used, 3133 i.e. x.x.x.4. 3134 3135 In the guest Windows OS, the line: 3136 3137 :: 3138 3139 10.0.2.4 smbserver 3140 3141 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3142 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3143 NT/2000). 3144 3145 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3146 3147 Note that a SAMBA server must be installed on the host OS. 3148 3149 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3150 Redirect incoming TCP or UDP connections to the host port 3151 hostport to the guest IP address guestaddr on guest port 3152 guestport. If guestaddr is not specified, its value is x.x.x.15 3153 (default first address given by the built-in DHCP server). By 3154 specifying hostaddr, the rule can be bound to a specific host 3155 interface. If no connection type is set, TCP is used. This 3156 option can be given multiple times. 3157 3158 For example, to redirect host X11 connection from screen 1 to 3159 guest screen 0, use the following: 3160 3161 .. parsed-literal:: 3162 3163 # on the host 3164 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3165 # this host xterm should open in the guest X11 server 3166 xterm -display :1 3167 3168 To redirect telnet connections from host port 5555 to telnet 3169 port on the guest, use the following: 3170 3171 .. parsed-literal:: 3172 3173 # on the host 3174 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3175 telnet localhost 5555 3176 3177 Then when you use on the host ``telnet localhost 5555``, you 3178 connect to the guest telnet server. 3179 3180 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3181 Forward guest TCP connections to the IP address server on port 3182 port to the character device dev or to a program executed by 3183 cmd:command which gets spawned for each connection. This option 3184 can be given multiple times. 3185 3186 You can either use a chardev directly and have that one used 3187 throughout QEMU's lifetime, like in the following example: 3188 3189 .. parsed-literal:: 3190 3191 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3192 # the guest accesses it 3193 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3194 3195 Or you can execute a command on every TCP connection established 3196 by the guest, so that QEMU behaves similar to an inetd process 3197 for that virtual server: 3198 3199 .. parsed-literal:: 3200 3201 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3202 # and connect the TCP stream to its stdin/stdout 3203 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3204 3205``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3206 Configure a host TAP network backend with ID id. 3207 3208 Use the network script file to configure it and the network script 3209 dfile to deconfigure it. If name is not provided, the OS 3210 automatically provides one. The default network configure script is 3211 ``/etc/qemu-ifup`` and the default network deconfigure script is 3212 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3213 disable script execution. 3214 3215 If running QEMU as an unprivileged user, use the network helper 3216 to configure the TAP interface and attach it to the bridge. 3217 The default network helper executable is 3218 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3219 ``br0``. 3220 3221 ``fd``\ =h can be used to specify the handle of an already opened 3222 host TAP interface. 3223 3224 Examples: 3225 3226 .. parsed-literal:: 3227 3228 #launch a QEMU instance with the default network script 3229 |qemu_system| linux.img -nic tap 3230 3231 .. parsed-literal:: 3232 3233 #launch a QEMU instance with two NICs, each one connected 3234 #to a TAP device 3235 |qemu_system| linux.img \\ 3236 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3237 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3238 3239 .. parsed-literal:: 3240 3241 #launch a QEMU instance with the default network helper to 3242 #connect a TAP device to bridge br0 3243 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3244 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3245 3246``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3247 Connect a host TAP network interface to a host bridge device. 3248 3249 Use the network helper helper to configure the TAP interface and 3250 attach it to the bridge. The default network helper executable is 3251 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3252 ``br0``. 3253 3254 Examples: 3255 3256 .. parsed-literal:: 3257 3258 #launch a QEMU instance with the default network helper to 3259 #connect a TAP device to bridge br0 3260 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3261 3262 .. parsed-literal:: 3263 3264 #launch a QEMU instance with the default network helper to 3265 #connect a TAP device to bridge qemubr0 3266 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3267 3268``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3269 This host network backend can be used to connect the guest's network 3270 to another QEMU virtual machine using a TCP socket connection. If 3271 ``listen`` is specified, QEMU waits for incoming connections on port 3272 (host is optional). ``connect`` is used to connect to another QEMU 3273 instance using the ``listen`` option. ``fd``\ =h specifies an 3274 already opened TCP socket. 3275 3276 Example: 3277 3278 .. parsed-literal:: 3279 3280 # launch a first QEMU instance 3281 |qemu_system| linux.img \\ 3282 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3283 -netdev socket,id=n1,listen=:1234 3284 # connect the network of this instance to the network of the first instance 3285 |qemu_system| linux.img \\ 3286 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3287 -netdev socket,id=n2,connect=127.0.0.1:1234 3288 3289``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3290 Configure a socket host network backend to share the guest's network 3291 traffic with another QEMU virtual machines using a UDP multicast 3292 socket, effectively making a bus for every QEMU with same multicast 3293 address maddr and port. NOTES: 3294 3295 1. Several QEMU can be running on different hosts and share same bus 3296 (assuming correct multicast setup for these hosts). 3297 3298 2. mcast support is compatible with User Mode Linux (argument 3299 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3300 3301 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3302 3303 Example: 3304 3305 .. parsed-literal:: 3306 3307 # launch one QEMU instance 3308 |qemu_system| linux.img \\ 3309 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3310 -netdev socket,id=n1,mcast=230.0.0.1:1234 3311 # launch another QEMU instance on same "bus" 3312 |qemu_system| linux.img \\ 3313 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3314 -netdev socket,id=n2,mcast=230.0.0.1:1234 3315 # launch yet another QEMU instance on same "bus" 3316 |qemu_system| linux.img \\ 3317 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3318 -netdev socket,id=n3,mcast=230.0.0.1:1234 3319 3320 Example (User Mode Linux compat.): 3321 3322 .. parsed-literal:: 3323 3324 # launch QEMU instance (note mcast address selected is UML's default) 3325 |qemu_system| linux.img \\ 3326 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3327 -netdev socket,id=n1,mcast=239.192.168.1:1102 3328 # launch UML 3329 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3330 3331 Example (send packets from host's 1.2.3.4): 3332 3333 .. parsed-literal:: 3334 3335 |qemu_system| linux.img \\ 3336 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3337 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3338 3339``-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]`` 3340 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3341 is a popular protocol to transport Ethernet (and other Layer 2) data 3342 frames between two systems. It is present in routers, firewalls and 3343 the Linux kernel (from version 3.3 onwards). 3344 3345 This transport allows a VM to communicate to another VM, router or 3346 firewall directly. 3347 3348 ``src=srcaddr`` 3349 source address (mandatory) 3350 3351 ``dst=dstaddr`` 3352 destination address (mandatory) 3353 3354 ``udp`` 3355 select udp encapsulation (default is ip). 3356 3357 ``srcport=srcport`` 3358 source udp port. 3359 3360 ``dstport=dstport`` 3361 destination udp port. 3362 3363 ``ipv6`` 3364 force v6, otherwise defaults to v4. 3365 3366 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3367 Cookies are a weak form of security in the l2tpv3 specification. 3368 Their function is mostly to prevent misconfiguration. By default 3369 they are 32 bit. 3370 3371 ``cookie64`` 3372 Set cookie size to 64 bit instead of the default 32 3373 3374 ``counter=off`` 3375 Force a 'cut-down' L2TPv3 with no counter as in 3376 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3377 3378 ``pincounter=on`` 3379 Work around broken counter handling in peer. This may also help 3380 on networks which have packet reorder. 3381 3382 ``offset=offset`` 3383 Add an extra offset between header and data 3384 3385 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3386 the bridge br-lan on the remote Linux host 1.2.3.4: 3387 3388 .. parsed-literal:: 3389 3390 # Setup tunnel on linux host using raw ip as encapsulation 3391 # on 1.2.3.4 3392 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3393 encap udp udp_sport 16384 udp_dport 16384 3394 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3395 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3396 ifconfig vmtunnel0 mtu 1500 3397 ifconfig vmtunnel0 up 3398 brctl addif br-lan vmtunnel0 3399 3400 3401 # on 4.3.2.1 3402 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3403 3404 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3405 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3406 3407``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3408 Configure VDE backend to connect to PORT n of a vde switch running 3409 on host and listening for incoming connections on socketpath. Use 3410 GROUP groupname and MODE octalmode to change default ownership and 3411 permissions for communication port. This option is only available if 3412 QEMU has been compiled with vde support enabled. 3413 3414 Example: 3415 3416 .. parsed-literal:: 3417 3418 # launch vde switch 3419 vde_switch -F -sock /tmp/myswitch 3420 # launch QEMU instance 3421 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3422 3423``-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]`` 3424 Configure AF_XDP backend to connect to a network interface 'name' 3425 using AF_XDP socket. A specific program attach mode for a default 3426 XDP program can be forced with 'mode', defaults to best-effort, 3427 where the likely most performant mode will be in use. Number of queues 3428 'n' should generally match the number or queues in the interface, 3429 defaults to 1. Traffic arriving on non-configured device queues will 3430 not be delivered to the network backend. 3431 3432 .. parsed-literal:: 3433 3434 # set number of queues to 4 3435 ethtool -L eth0 combined 4 3436 # launch QEMU instance 3437 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3438 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3439 3440 'start-queue' option can be specified if a particular range of queues 3441 [m, m + n] should be in use. For example, this is may be necessary in 3442 order to use certain NICs in native mode. Kernel allows the driver to 3443 create a separate set of XDP queues on top of regular ones, and only 3444 these queues can be used for AF_XDP sockets. NICs that work this way 3445 may also require an additional traffic redirection with ethtool to these 3446 special queues. 3447 3448 .. parsed-literal:: 3449 3450 # set number of queues to 1 3451 ethtool -L eth0 combined 1 3452 # redirect all the traffic to the second queue (id: 1) 3453 # note: drivers may require non-empty key/mask pair. 3454 ethtool -N eth0 flow-type ether \\ 3455 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3456 ethtool -N eth0 flow-type ether \\ 3457 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3458 # launch QEMU instance 3459 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3460 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3461 3462 XDP program can also be loaded externally. In this case 'inhibit' option 3463 should be set to 'on' and 'sock-fds' provided with file descriptors for 3464 already open but not bound XDP sockets already added to a socket map for 3465 corresponding queues. One socket per queue. 3466 3467 .. parsed-literal:: 3468 3469 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3470 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3471 3472``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3473 Establish a vhost-user netdev, backed by a chardev id. The chardev 3474 should be a unix domain socket backed one. The vhost-user uses a 3475 specifically defined protocol to pass vhost ioctl replacement 3476 messages to an application on the other end of the socket. On 3477 non-MSIX guests, the feature can be forced with vhostforce. Use 3478 'queues=n' to specify the number of queues to be created for 3479 multiqueue vhost-user. 3480 3481 Example: 3482 3483 :: 3484 3485 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3486 -numa node,memdev=mem \ 3487 -chardev socket,id=chr0,path=/path/to/socket \ 3488 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3489 -device virtio-net-pci,netdev=net0 3490 3491``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3492 Establish a vhost-vdpa netdev. 3493 3494 vDPA device is a device that uses a datapath which complies with 3495 the virtio specifications with a vendor specific control path. 3496 vDPA devices can be both physically located on the hardware or 3497 emulated by software. 3498 3499``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3500 Create a hub port on the emulated hub with ID hubid. 3501 3502 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3503 instead of a single netdev. Alternatively, you can also connect the 3504 hubport to another netdev with ID nd by using the ``netdev=nd`` 3505 option. 3506 3507``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3508 Legacy option to configure or create an on-board (or machine 3509 default) Network Interface Card(NIC) and connect it either to the 3510 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3511 If model is omitted, then the default NIC model associated with the 3512 machine type is used. Note that the default NIC model may change in 3513 future QEMU releases, so it is highly recommended to always specify 3514 a model. Optionally, the MAC address can be changed to mac, the 3515 device address set to addr (PCI cards only), and a name can be 3516 assigned for use in monitor commands. Optionally, for PCI cards, you 3517 can specify the number v of MSI-X vectors that the card should have; 3518 this option currently only affects virtio cards; set v = 0 to 3519 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3520 created. QEMU can emulate several different models of network card. 3521 Use ``-net nic,model=help`` for a list of available devices for your 3522 target. 3523 3524``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3525 Configure a host network backend (with the options corresponding to 3526 the same ``-netdev`` option) and connect it to the emulated hub 0 3527 (the default hub). Use name to specify the name of the hub port. 3528ERST 3529 3530DEFHEADING() 3531 3532DEFHEADING(Character device options:) 3533 3534DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3535 "-chardev help\n" 3536 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3537 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3538 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3539 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3540 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3541 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3542 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3543 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3544 " [,logfile=PATH][,logappend=on|off]\n" 3545 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3546 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3547 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3548 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3549 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3550 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3551#ifdef _WIN32 3552 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3553 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3554#else 3555 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3556 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3557#endif 3558#ifdef CONFIG_BRLAPI 3559 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3560#endif 3561#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3562 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3563 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3564#endif 3565#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3566 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3567#endif 3568#if defined(CONFIG_SPICE) 3569 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3570 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3571#endif 3572 , QEMU_ARCH_ALL 3573) 3574 3575SRST 3576The general form of a character device option is: 3577 3578``-chardev backend,id=id[,mux=on|off][,options]`` 3579 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3580 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3581 ``pty``, ``stdio``, ``braille``, ``parallel``, 3582 ``spicevmc``, ``spiceport``. The specific backend will determine the 3583 applicable options. 3584 3585 Use ``-chardev help`` to print all available chardev backend types. 3586 3587 All devices must have an id, which can be any string up to 127 3588 characters long. It is used to uniquely identify this device in 3589 other command line directives. 3590 3591 A character device may be used in multiplexing mode by multiple 3592 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3593 a "1:N" device, and here the "1" end is your specified chardev 3594 backend, and the "N" end is the various parts of QEMU that can talk 3595 to a chardev. If you create a chardev with ``id=myid`` and 3596 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3597 and you can then configure multiple front ends to use that chardev 3598 ID for their input/output. Up to four different front ends can be 3599 connected to a single multiplexed chardev. (Without multiplexing 3600 enabled, a chardev can only be used by a single front end.) For 3601 instance you could use this to allow a single stdio chardev to be 3602 used by two serial ports and the QEMU monitor: 3603 3604 :: 3605 3606 -chardev stdio,mux=on,id=char0 \ 3607 -mon chardev=char0,mode=readline \ 3608 -serial chardev:char0 \ 3609 -serial chardev:char0 3610 3611 You can have more than one multiplexer in a system configuration; 3612 for instance you could have a TCP port multiplexed between UART 0 3613 and UART 1, and stdio multiplexed between the QEMU monitor and a 3614 parallel port: 3615 3616 :: 3617 3618 -chardev stdio,mux=on,id=char0 \ 3619 -mon chardev=char0,mode=readline \ 3620 -parallel chardev:char0 \ 3621 -chardev tcp,...,mux=on,id=char1 \ 3622 -serial chardev:char1 \ 3623 -serial chardev:char1 3624 3625 When you're using a multiplexed character device, some escape 3626 sequences are interpreted in the input. See the chapter about 3627 :ref:`keys in the character backend multiplexer` in the 3628 System Emulation Users Guide for more details. 3629 3630 Note that some other command line options may implicitly create 3631 multiplexed character backends; for instance ``-serial mon:stdio`` 3632 creates a multiplexed stdio backend connected to the serial port and 3633 the QEMU monitor, and ``-nographic`` also multiplexes the console 3634 and the monitor to stdio. 3635 3636 There is currently no support for multiplexing in the other 3637 direction (where a single QEMU front end takes input and output from 3638 multiple chardevs). 3639 3640 Every backend supports the ``logfile`` option, which supplies the 3641 path to a file to record all data transmitted via the backend. The 3642 ``logappend`` option controls whether the log file will be truncated 3643 or appended to when opened. 3644 3645The available backends are: 3646 3647``-chardev null,id=id`` 3648 A void device. This device will not emit any data, and will drop any 3649 data it receives. The null backend does not take any options. 3650 3651``-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]`` 3652 Create a two-way stream socket, which can be either a TCP or a unix 3653 socket. A unix socket will be created if ``path`` is specified. 3654 Behaviour is undefined if TCP options are specified for a unix 3655 socket. 3656 3657 ``server=on|off`` specifies that the socket shall be a listening socket. 3658 3659 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3660 to connect to a listening socket. 3661 3662 ``telnet=on|off`` specifies that traffic on the socket should interpret 3663 telnet escape sequences. 3664 3665 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3666 communication. 3667 3668 ``reconnect`` sets the timeout for reconnecting on non-server 3669 sockets when the remote end goes away. qemu will delay this many 3670 seconds and then attempt to reconnect. Zero disables reconnecting, 3671 and is the default. 3672 3673 ``tls-creds`` requests enablement of the TLS protocol for 3674 encryption, and specifies the id of the TLS credentials to use for 3675 the handshake. The credentials must be previously created with the 3676 ``-object tls-creds`` argument. 3677 3678 ``tls-auth`` provides the ID of the QAuthZ authorization object 3679 against which the client's x509 distinguished name will be 3680 validated. This object is only resolved at time of use, so can be 3681 deleted and recreated on the fly while the chardev server is active. 3682 If missing, it will default to denying access. 3683 3684 TCP and unix socket options are given below: 3685 3686 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3687 ``host`` for a listening socket specifies the local address to 3688 be bound. For a connecting socket species the remote host to 3689 connect to. ``host`` is optional for listening sockets. If not 3690 specified it defaults to ``0.0.0.0``. 3691 3692 ``port`` for a listening socket specifies the local port to be 3693 bound. For a connecting socket specifies the port on the remote 3694 host to connect to. ``port`` can be given as either a port 3695 number or a service name. ``port`` is required. 3696 3697 ``to`` is only relevant to listening sockets. If it is 3698 specified, and ``port`` cannot be bound, QEMU will attempt to 3699 bind to subsequent ports up to and including ``to`` until it 3700 succeeds. ``to`` must be specified as a port number. 3701 3702 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3703 or IPv6 must be used. If neither is specified the socket may 3704 use either protocol. 3705 3706 ``nodelay=on|off`` disables the Nagle algorithm. 3707 3708 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3709 ``path`` specifies the local path of the unix socket. ``path`` 3710 is required. 3711 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3712 rather than the filesystem. Optional, defaults to false. 3713 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3714 rather than the full sun_path length. Optional, defaults to true. 3715 3716``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3717 Sends all traffic from the guest to a remote host over UDP. 3718 3719 ``host`` specifies the remote host to connect to. If not specified 3720 it defaults to ``localhost``. 3721 3722 ``port`` specifies the port on the remote host to connect to. 3723 ``port`` is required. 3724 3725 ``localaddr`` specifies the local address to bind to. If not 3726 specified it defaults to ``0.0.0.0``. 3727 3728 ``localport`` specifies the local port to bind to. If not specified 3729 any available local port will be used. 3730 3731 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3732 If neither is specified the device may use either protocol. 3733 3734``-chardev msmouse,id=id`` 3735 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3736 does not take any options. 3737 3738``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3739 Connect to a QEMU text console. ``vc`` may optionally be given a 3740 specific size. 3741 3742 ``width`` and ``height`` specify the width and height respectively 3743 of the console, in pixels. 3744 3745 ``cols`` and ``rows`` specify that the console be sized to fit a 3746 text console with the given dimensions. 3747 3748``-chardev ringbuf,id=id[,size=size]`` 3749 Create a ring buffer with fixed size ``size``. size must be a power 3750 of two and defaults to ``64K``. 3751 3752``-chardev file,id=id,path=path[,input-path=input-path]`` 3753 Log all traffic received from the guest to a file. 3754 3755 ``path`` specifies the path of the file to be opened. This file will 3756 be created if it does not already exist, and overwritten if it does. 3757 ``path`` is required. 3758 3759 If ``input-path`` is specified, this is the path of a second file 3760 which will be used for input. If ``input-path`` is not specified, 3761 no input will be available from the chardev. 3762 3763 Note that ``input-path`` is not supported on Windows hosts. 3764 3765``-chardev pipe,id=id,path=path`` 3766 Create a two-way connection to the guest. The behaviour differs 3767 slightly between Windows hosts and other hosts: 3768 3769 On Windows, a single duplex pipe will be created at 3770 ``\\.pipe\path``. 3771 3772 On other hosts, 2 pipes will be created called ``path.in`` and 3773 ``path.out``. Data written to ``path.in`` will be received by the 3774 guest. Data written by the guest can be read from ``path.out``. QEMU 3775 will not create these fifos, and requires them to be present. 3776 3777 ``path`` forms part of the pipe path as described above. ``path`` is 3778 required. 3779 3780``-chardev console,id=id`` 3781 Send traffic from the guest to QEMU's standard output. ``console`` 3782 does not take any options. 3783 3784 ``console`` is only available on Windows hosts. 3785 3786``-chardev serial,id=id,path=path`` 3787 Send traffic from the guest to a serial device on the host. 3788 3789 On Unix hosts serial will actually accept any tty device, not only 3790 serial lines. 3791 3792 ``path`` specifies the name of the serial device to open. 3793 3794``-chardev pty,id=id`` 3795 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3796 does not take any options. 3797 3798 ``pty`` is not available on Windows hosts. 3799 3800``-chardev stdio,id=id[,signal=on|off]`` 3801 Connect to standard input and standard output of the QEMU process. 3802 3803 ``signal`` controls if signals are enabled on the terminal, that 3804 includes exiting QEMU with the key sequence Control-c. This option 3805 is enabled by default, use ``signal=off`` to disable it. 3806 3807``-chardev braille,id=id`` 3808 Connect to a local BrlAPI server. ``braille`` does not take any 3809 options. 3810 3811``-chardev parallel,id=id,path=path`` 3812 \ 3813 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3814 hosts. 3815 3816 Connect to a local parallel port. 3817 3818 ``path`` specifies the path to the parallel port device. ``path`` is 3819 required. 3820 3821``-chardev spicevmc,id=id,debug=debug,name=name`` 3822 ``spicevmc`` is only available when spice support is built in. 3823 3824 ``debug`` debug level for spicevmc 3825 3826 ``name`` name of spice channel to connect to 3827 3828 Connect to a spice virtual machine channel, such as vdiport. 3829 3830``-chardev spiceport,id=id,debug=debug,name=name`` 3831 ``spiceport`` is only available when spice support is built in. 3832 3833 ``debug`` debug level for spicevmc 3834 3835 ``name`` name of spice port to connect to 3836 3837 Connect to a spice port, allowing a Spice client to handle the 3838 traffic identified by a name (preferably a fqdn). 3839ERST 3840 3841DEFHEADING() 3842 3843#ifdef CONFIG_TPM 3844DEFHEADING(TPM device options:) 3845 3846DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3847 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3848 " use path to provide path to a character device; default is /dev/tpm0\n" 3849 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3850 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3851 "-tpmdev emulator,id=id,chardev=dev\n" 3852 " configure the TPM device using chardev backend\n", 3853 QEMU_ARCH_ALL) 3854SRST 3855The general form of a TPM device option is: 3856 3857``-tpmdev backend,id=id[,options]`` 3858 The specific backend type will determine the applicable options. The 3859 ``-tpmdev`` option creates the TPM backend and requires a 3860 ``-device`` option that specifies the TPM frontend interface model. 3861 3862 Use ``-tpmdev help`` to print all available TPM backend types. 3863 3864The available backends are: 3865 3866``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3867 (Linux-host only) Enable access to the host's TPM using the 3868 passthrough driver. 3869 3870 ``path`` specifies the path to the host's TPM device, i.e., on a 3871 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3872 default ``/dev/tpm0`` is used. 3873 3874 ``cancel-path`` specifies the path to the host TPM device's sysfs 3875 entry allowing for cancellation of an ongoing TPM command. 3876 ``cancel-path`` is optional and by default QEMU will search for the 3877 sysfs entry to use. 3878 3879 Some notes about using the host's TPM with the passthrough driver: 3880 3881 The TPM device accessed by the passthrough driver must not be used 3882 by any other application on the host. 3883 3884 Since the host's firmware (BIOS/UEFI) has already initialized the 3885 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3886 the TPM again and may therefore not show a TPM-specific menu that 3887 would otherwise allow the user to configure the TPM, e.g., allow the 3888 user to enable/disable or activate/deactivate the TPM. Further, if 3889 TPM ownership is released from within a VM then the host's TPM will 3890 get disabled and deactivated. To enable and activate the TPM again 3891 afterwards, the host has to be rebooted and the user is required to 3892 enter the firmware's menu to enable and activate the TPM. If the TPM 3893 is left disabled and/or deactivated most TPM commands will fail. 3894 3895 To create a passthrough TPM use the following two options: 3896 3897 :: 3898 3899 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3900 3901 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3902 ``tpmdev=tpm0`` in the device option. 3903 3904``-tpmdev emulator,id=id,chardev=dev`` 3905 (Linux-host only) Enable access to a TPM emulator using Unix domain 3906 socket based chardev backend. 3907 3908 ``chardev`` specifies the unique ID of a character device backend 3909 that provides connection to the software TPM server. 3910 3911 To create a TPM emulator backend device with chardev socket backend: 3912 3913 :: 3914 3915 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3916ERST 3917 3918DEFHEADING() 3919 3920#endif 3921 3922DEFHEADING(Boot Image or Kernel specific:) 3923SRST 3924There are broadly 4 ways you can boot a system with QEMU. 3925 3926 - specify a firmware and let it control finding a kernel 3927 - specify a firmware and pass a hint to the kernel to boot 3928 - direct kernel image boot 3929 - manually load files into the guest's address space 3930 3931The third method is useful for quickly testing kernels but as there is 3932no firmware to pass configuration information to the kernel the 3933hardware must either be probeable, the kernel built for the exact 3934configuration or passed some configuration data (e.g. a DTB blob) 3935which tells the kernel what drivers it needs. This exact details are 3936often hardware specific. 3937 3938The final method is the most generic way of loading images into the 3939guest address space and used mostly for ``bare metal`` type 3940development where the reset vectors of the processor are taken into 3941account. 3942 3943ERST 3944 3945SRST 3946 3947For x86 machines and some other architectures ``-bios`` will generally 3948do the right thing with whatever it is given. For other machines the 3949more strict ``-pflash`` option needs an image that is sized for the 3950flash device for the given machine type. 3951 3952Please see the :ref:`system-targets-ref` section of the manual for 3953more detailed documentation. 3954 3955ERST 3956 3957DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3958 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3959SRST 3960``-bios file`` 3961 Set the filename for the BIOS. 3962ERST 3963 3964DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3965 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3966SRST 3967``-pflash file`` 3968 Use file as a parallel flash image. 3969ERST 3970 3971SRST 3972 3973The kernel options were designed to work with Linux kernels although 3974other things (like hypervisors) can be packaged up as a kernel 3975executable image. The exact format of a executable image is usually 3976architecture specific. 3977 3978The way in which the kernel is started (what address it is loaded at, 3979what if any information is passed to it via CPU registers, the state 3980of the hardware when it is started, and so on) is also architecture 3981specific. Typically it follows the specification laid down by the 3982Linux kernel for how kernels for that architecture must be started. 3983 3984ERST 3985 3986DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3987 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3988SRST 3989``-kernel bzImage`` 3990 Use bzImage as kernel image. The kernel can be either a Linux kernel 3991 or in multiboot format. 3992ERST 3993 3994DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3995 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3996SRST 3997``-append cmdline`` 3998 Use cmdline as kernel command line 3999ERST 4000 4001DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4002 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4003SRST(initrd) 4004 4005``-initrd file`` 4006 Use file as initial ram disk. 4007 4008``-initrd "file1 arg=foo,file2"`` 4009 This syntax is only available with multiboot. 4010 4011 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4012 first module. Commas can be provided in module parameters by doubling 4013 them on the command line to escape them: 4014 4015``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4016 Multiboot only. Use bzImage as the first module with 4017 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4018 and initrd.img as the second module. 4019 4020ERST 4021 4022DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4023 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4024SRST 4025``-dtb file`` 4026 Use file as a device tree binary (dtb) image and pass it to the 4027 kernel on boot. 4028ERST 4029 4030SRST 4031 4032Finally you can also manually load images directly into the address 4033space of the guest. This is most useful for developers who already 4034know the layout of their guest and take care to ensure something sane 4035will happen when the reset vector executes. 4036 4037The generic loader can be invoked by using the loader device: 4038 4039``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4040 4041there is also the guest loader which operates in a similar way but 4042tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4043the guest image is: 4044 4045``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4046 4047ERST 4048 4049DEFHEADING() 4050 4051DEFHEADING(Debug/Expert options:) 4052 4053DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4054 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4055 " Policy for handling deprecated management interfaces\n" 4056 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4057 " Policy for handling unstable management interfaces\n", 4058 QEMU_ARCH_ALL) 4059SRST 4060``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4061 Set policy for handling deprecated management interfaces (experimental): 4062 4063 ``deprecated-input=accept`` (default) 4064 Accept deprecated commands and arguments 4065 ``deprecated-input=reject`` 4066 Reject deprecated commands and arguments 4067 ``deprecated-input=crash`` 4068 Crash on deprecated commands and arguments 4069 ``deprecated-output=accept`` (default) 4070 Emit deprecated command results and events 4071 ``deprecated-output=hide`` 4072 Suppress deprecated command results and events 4073 4074 Limitation: covers only syntactic aspects of QMP. 4075 4076``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4077 Set policy for handling unstable management interfaces (experimental): 4078 4079 ``unstable-input=accept`` (default) 4080 Accept unstable commands and arguments 4081 ``unstable-input=reject`` 4082 Reject unstable commands and arguments 4083 ``unstable-input=crash`` 4084 Crash on unstable commands and arguments 4085 ``unstable-output=accept`` (default) 4086 Emit unstable command results and events 4087 ``unstable-output=hide`` 4088 Suppress unstable command results and events 4089 4090 Limitation: covers only syntactic aspects of QMP. 4091ERST 4092 4093DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4094 "-fw_cfg [name=]<name>,file=<file>\n" 4095 " add named fw_cfg entry with contents from file\n" 4096 "-fw_cfg [name=]<name>,string=<str>\n" 4097 " add named fw_cfg entry with contents from string\n", 4098 QEMU_ARCH_ALL) 4099SRST 4100``-fw_cfg [name=]name,file=file`` 4101 Add named fw\_cfg entry with contents from file file. 4102 If the filename contains comma, you must double it (for instance, 4103 "file=my,,file" to use file "my,file"). 4104 4105``-fw_cfg [name=]name,string=str`` 4106 Add named fw\_cfg entry with contents from string str. 4107 If the string contains comma, you must double it (for instance, 4108 "string=my,,string" to use file "my,string"). 4109 4110 The terminating NUL character of the contents of str will not be 4111 included as part of the fw\_cfg item data. To insert contents with 4112 embedded NUL characters, you have to use the file parameter. 4113 4114 The fw\_cfg entries are passed by QEMU through to the guest. 4115 4116 Example: 4117 4118 :: 4119 4120 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4121 4122 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4123 from ./my\_blob.bin. 4124ERST 4125 4126DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4127 "-serial dev redirect the serial port to char device 'dev'\n", 4128 QEMU_ARCH_ALL) 4129SRST 4130``-serial dev`` 4131 Redirect the virtual serial port to host character device dev. The 4132 default device is ``vc`` in graphical mode and ``stdio`` in non 4133 graphical mode. 4134 4135 This option can be used several times to simulate multiple serial 4136 ports. 4137 4138 You can use ``-serial none`` to suppress the creation of default 4139 serial devices. 4140 4141 Available character devices are: 4142 4143 ``vc[:WxH]`` 4144 Virtual console. Optionally, a width and height can be given in 4145 pixel with 4146 4147 :: 4148 4149 vc:800x600 4150 4151 It is also possible to specify width or height in characters: 4152 4153 :: 4154 4155 vc:80Cx24C 4156 4157 ``pty`` 4158 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4159 4160 ``none`` 4161 No device is allocated. Note that for machine types which 4162 emulate systems where a serial device is always present in 4163 real hardware, this may be equivalent to the ``null`` option, 4164 in that the serial device is still present but all output 4165 is discarded. For boards where the number of serial ports is 4166 truly variable, this suppresses the creation of the device. 4167 4168 ``null`` 4169 A guest will see the UART or serial device as present in the 4170 machine, but all output is discarded, and there is no input. 4171 Conceptually equivalent to redirecting the output to ``/dev/null``. 4172 4173 ``chardev:id`` 4174 Use a named character device defined with the ``-chardev`` 4175 option. 4176 4177 ``/dev/XXX`` 4178 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4179 port parameters are set according to the emulated ones. 4180 4181 ``/dev/parportN`` 4182 [Linux only, parallel port only] Use host parallel port N. 4183 Currently SPP and EPP parallel port features can be used. 4184 4185 ``file:filename`` 4186 Write output to filename. No character can be read. 4187 4188 ``stdio`` 4189 [Unix only] standard input/output 4190 4191 ``pipe:filename`` 4192 name pipe filename 4193 4194 ``COMn`` 4195 [Windows only] Use host serial port n 4196 4197 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4198 This implements UDP Net Console. When remote\_host or src\_ip 4199 are not specified they default to ``0.0.0.0``. When not using a 4200 specified src\_port a random port is automatically chosen. 4201 4202 If you just want a simple readonly console you can use 4203 ``netcat`` or ``nc``, by starting QEMU with: 4204 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4205 QEMU writes something to that port it will appear in the 4206 netconsole session. 4207 4208 If you plan to send characters back via netconsole or you want 4209 to stop and start QEMU a lot of times, you should have QEMU use 4210 the same source port each time by using something like ``-serial 4211 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4212 version of netcat which can listen to a TCP port and send and 4213 receive characters via udp. If you have a patched version of 4214 netcat which activates telnet remote echo and single char 4215 transfer, then you can use the following options to set up a 4216 netcat redirector to allow telnet on port 5555 to access the 4217 QEMU port. 4218 4219 ``QEMU Options:`` 4220 -serial udp::4555@:4556 4221 4222 ``netcat options:`` 4223 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4224 4225 ``telnet options:`` 4226 localhost 5555 4227 4228 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4229 The TCP Net Console has two modes of operation. It can send the 4230 serial I/O to a location or wait for a connection from a 4231 location. By default the TCP Net Console is sent to host at the 4232 port. If you use the ``server=on`` option QEMU will wait for a client 4233 socket application to connect to the port before continuing, 4234 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4235 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4236 option only applies if ``server=no`` is set, if the connection goes 4237 down it will attempt to reconnect at the given interval. If host 4238 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4239 time is accepted. You can use ``telnet=on`` to connect to the 4240 corresponding character device. 4241 4242 ``Example to send tcp console to 192.168.0.2 port 4444`` 4243 -serial tcp:192.168.0.2:4444 4244 4245 ``Example to listen and wait on port 4444 for connection`` 4246 -serial tcp::4444,server=on 4247 4248 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4249 -serial tcp:192.168.0.100:4444,server=on,wait=off 4250 4251 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4252 The telnet protocol is used instead of raw tcp sockets. The 4253 options work the same as if you had specified ``-serial tcp``. 4254 The difference is that the port acts like a telnet server or 4255 client using telnet option negotiation. This will also allow you 4256 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4257 supports sending the break sequence. Typically in unix telnet 4258 you do it with Control-] and then type "send break" followed by 4259 pressing the enter key. 4260 4261 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4262 The WebSocket protocol is used instead of raw tcp socket. The 4263 port acts as a WebSocket server. Client mode is not supported. 4264 4265 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4266 A unix domain socket is used instead of a tcp socket. The option 4267 works the same as if you had specified ``-serial tcp`` except 4268 the unix domain socket path is used for connections. 4269 4270 ``mon:dev_string`` 4271 This is a special option to allow the monitor to be multiplexed 4272 onto another serial port. The monitor is accessed with key 4273 sequence of Control-a and then pressing c. dev\_string should be 4274 any one of the serial devices specified above. An example to 4275 multiplex the monitor onto a telnet server listening on port 4276 4444 would be: 4277 4278 ``-serial mon:telnet::4444,server=on,wait=off`` 4279 4280 When the monitor is multiplexed to stdio in this way, Ctrl+C 4281 will not terminate QEMU any more but will be passed to the guest 4282 instead. 4283 4284 ``braille`` 4285 Braille device. This will use BrlAPI to display the braille 4286 output on a real or fake device. 4287 4288 ``msmouse`` 4289 Three button serial mouse. Configure the guest to use Microsoft 4290 protocol. 4291ERST 4292 4293DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4294 "-parallel dev redirect the parallel port to char device 'dev'\n", 4295 QEMU_ARCH_ALL) 4296SRST 4297``-parallel dev`` 4298 Redirect the virtual parallel port to host device dev (same devices 4299 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4300 to use hardware devices connected on the corresponding host parallel 4301 port. 4302 4303 This option can be used several times to simulate up to 3 parallel 4304 ports. 4305 4306 Use ``-parallel none`` to disable all parallel ports. 4307ERST 4308 4309DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4310 "-monitor dev redirect the monitor to char device 'dev'\n", 4311 QEMU_ARCH_ALL) 4312SRST 4313``-monitor dev`` 4314 Redirect the monitor to host device dev (same devices as the serial 4315 port). The default device is ``vc`` in graphical mode and ``stdio`` 4316 in non graphical mode. Use ``-monitor none`` to disable the default 4317 monitor. 4318ERST 4319DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4320 "-qmp dev like -monitor but opens in 'control' mode\n", 4321 QEMU_ARCH_ALL) 4322SRST 4323``-qmp dev`` 4324 Like ``-monitor`` but opens in 'control' mode. For example, to make 4325 QMP available on localhost port 4444:: 4326 4327 -qmp tcp:localhost:4444,server=on,wait=off 4328 4329 Not all options are configurable via this syntax; for maximum 4330 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4331 4332ERST 4333DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4334 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4335 QEMU_ARCH_ALL) 4336SRST 4337``-qmp-pretty dev`` 4338 Like ``-qmp`` but uses pretty JSON formatting. 4339ERST 4340 4341DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4342 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4343SRST 4344``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4345 Set up a monitor connected to the chardev ``name``. 4346 QEMU supports two monitors: the Human Monitor Protocol 4347 (HMP; for human interaction), and the QEMU Monitor Protocol 4348 (QMP; a JSON RPC-style protocol). 4349 The default is HMP; ``mode=control`` selects QMP instead. 4350 ``pretty`` is only valid when ``mode=control``, 4351 turning on JSON pretty printing to ease 4352 human reading and debugging. 4353 4354 For example:: 4355 4356 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4357 -mon chardev=mon1,mode=control,pretty=on 4358 4359 enables the QMP monitor on localhost port 4444 with pretty-printing. 4360ERST 4361 4362DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4363 "-debugcon dev redirect the debug console to char device 'dev'\n", 4364 QEMU_ARCH_ALL) 4365SRST 4366``-debugcon dev`` 4367 Redirect the debug console to host device dev (same devices as the 4368 serial port). The debug console is an I/O port which is typically 4369 port 0xe9; writing to that I/O port sends output to this device. The 4370 default device is ``vc`` in graphical mode and ``stdio`` in non 4371 graphical mode. 4372ERST 4373 4374DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4375 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4376SRST 4377``-pidfile file`` 4378 Store the QEMU process PID in file. It is useful if you launch QEMU 4379 from a script. 4380ERST 4381 4382DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4383 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4384 QEMU_ARCH_ALL) 4385SRST 4386``--preconfig`` 4387 Pause QEMU for interactive configuration before the machine is 4388 created, which allows querying and configuring properties that will 4389 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4390 exit the preconfig state and move to the next state (i.e. run guest 4391 if -S isn't used or pause the second time if -S is used). This 4392 option is experimental. 4393ERST 4394 4395DEF("S", 0, QEMU_OPTION_S, \ 4396 "-S freeze CPU at startup (use 'c' to start execution)\n", 4397 QEMU_ARCH_ALL) 4398SRST 4399``-S`` 4400 Do not start CPU at startup (you must type 'c' in the monitor). 4401ERST 4402 4403DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4404 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4405 " run qemu with overcommit hints\n" 4406 " mem-lock=on|off controls memory lock support (default: off)\n" 4407 " cpu-pm=on|off controls cpu power management (default: off)\n", 4408 QEMU_ARCH_ALL) 4409SRST 4410``-overcommit mem-lock=on|off`` 4411 \ 4412``-overcommit cpu-pm=on|off`` 4413 Run qemu with hints about host resource overcommit. The default is 4414 to assume that host overcommits all resources. 4415 4416 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4417 (disabled by default). This works when host memory is not 4418 overcommitted and reduces the worst-case latency for guest. 4419 4420 Guest ability to manage power state of host cpus (increasing latency 4421 for other processes on the same host cpu, but decreasing latency for 4422 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4423 works best when host CPU is not overcommitted. When used, host 4424 estimates of CPU cycle and power utilization will be incorrect, not 4425 taking into account guest idle time. 4426ERST 4427 4428DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4429 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4430 " the guest without waiting for gdb to connect; use -S too\n" 4431 " if you want it to not start execution.)\n", 4432 QEMU_ARCH_ALL) 4433SRST 4434``-gdb dev`` 4435 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4436 in the System Emulation Users Guide). Note that this option does not pause QEMU 4437 execution -- if you want QEMU to not start the guest until you 4438 connect with gdb and issue a ``continue`` command, you will need to 4439 also pass the ``-S`` option to QEMU. 4440 4441 The most usual configuration is to listen on a local TCP socket:: 4442 4443 -gdb tcp::3117 4444 4445 but you can specify other backends; UDP, pseudo TTY, or even stdio 4446 are all reasonable use cases. For example, a stdio connection 4447 allows you to start QEMU from within gdb and establish the 4448 connection via a pipe: 4449 4450 .. parsed-literal:: 4451 4452 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4453ERST 4454 4455DEF("s", 0, QEMU_OPTION_s, \ 4456 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4457 QEMU_ARCH_ALL) 4458SRST 4459``-s`` 4460 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4461 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4462ERST 4463 4464DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4465 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4466 QEMU_ARCH_ALL) 4467SRST 4468``-d item1[,...]`` 4469 Enable logging of specified items. Use '-d help' for a list of log 4470 items. 4471ERST 4472 4473DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4474 "-D logfile output log to logfile (default stderr)\n", 4475 QEMU_ARCH_ALL) 4476SRST 4477``-D logfile`` 4478 Output log in logfile instead of to stderr 4479ERST 4480 4481DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4482 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4483 QEMU_ARCH_ALL) 4484SRST 4485``-dfilter range1[,...]`` 4486 Filter debug output to that relevant to a range of target addresses. 4487 The filter spec can be either start+size, start-size or start..end 4488 where start end and size are the addresses and sizes required. For 4489 example: 4490 4491 :: 4492 4493 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4494 4495 Will dump output for any code in the 0x1000 sized block starting at 4496 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4497 another 0x1000 sized block starting at 0xffffffc00005f000. 4498ERST 4499 4500DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4501 "-seed number seed the pseudo-random number generator\n", 4502 QEMU_ARCH_ALL) 4503SRST 4504``-seed number`` 4505 Force the guest to use a deterministic pseudo-random number 4506 generator, seeded with number. This does not affect crypto routines 4507 within the host. 4508ERST 4509 4510DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4511 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4512 QEMU_ARCH_ALL) 4513SRST 4514``-L path`` 4515 Set the directory for the BIOS, VGA BIOS and keymaps. 4516 4517 To list all the data directories, use ``-L help``. 4518ERST 4519 4520DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4521 "-enable-kvm enable KVM full virtualization support\n", 4522 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4523 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4524SRST 4525``-enable-kvm`` 4526 Enable KVM full virtualization support. This option is only 4527 available if KVM support is enabled when compiling. 4528ERST 4529 4530DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4531 "-xen-domid id specify xen guest domain id\n", 4532 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4533DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4534 "-xen-attach attach to existing xen domain\n" 4535 " libxl will use this when starting QEMU\n", 4536 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4537DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4538 "-xen-domid-restrict restrict set of available xen operations\n" 4539 " to specified domain id. (Does not affect\n" 4540 " xenpv machine type).\n", 4541 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4542SRST 4543``-xen-domid id`` 4544 Specify xen guest domain id (XEN only). 4545 4546``-xen-attach`` 4547 Attach to existing xen domain. libxl will use this when starting 4548 QEMU (XEN only). Restrict set of available xen operations to 4549 specified domain id (XEN only). 4550ERST 4551 4552DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4553 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4554SRST 4555``-no-reboot`` 4556 Exit instead of rebooting. 4557ERST 4558 4559DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4560 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4561SRST 4562``-no-shutdown`` 4563 Don't exit QEMU on guest shutdown, but instead only stop the 4564 emulation. This allows for instance switching to monitor to commit 4565 changes to the disk image. 4566ERST 4567 4568DEF("action", HAS_ARG, QEMU_OPTION_action, 4569 "-action reboot=reset|shutdown\n" 4570 " action when guest reboots [default=reset]\n" 4571 "-action shutdown=poweroff|pause\n" 4572 " action when guest shuts down [default=poweroff]\n" 4573 "-action panic=pause|shutdown|exit-failure|none\n" 4574 " action when guest panics [default=shutdown]\n" 4575 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4576 " action when watchdog fires [default=reset]\n", 4577 QEMU_ARCH_ALL) 4578SRST 4579``-action event=action`` 4580 The action parameter serves to modify QEMU's default behavior when 4581 certain guest events occur. It provides a generic method for specifying the 4582 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4583 parameters. 4584 4585 Examples: 4586 4587 ``-action panic=none`` 4588 ``-action reboot=shutdown,shutdown=pause`` 4589 ``-device i6300esb -action watchdog=pause`` 4590 4591ERST 4592 4593DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4594 "-loadvm [tag|id]\n" \ 4595 " start right away with a saved state (loadvm in monitor)\n", 4596 QEMU_ARCH_ALL) 4597SRST 4598``-loadvm file`` 4599 Start right away with a saved state (``loadvm`` in monitor) 4600ERST 4601 4602#ifndef _WIN32 4603DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4604 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4605#endif 4606SRST 4607``-daemonize`` 4608 Daemonize the QEMU process after initialization. QEMU will not 4609 detach from standard IO until it is ready to receive connections on 4610 any of its devices. This option is a useful way for external 4611 programs to launch QEMU without having to cope with initialization 4612 race conditions. 4613ERST 4614 4615DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4616 "-option-rom rom load a file, rom, into the option ROM space\n", 4617 QEMU_ARCH_ALL) 4618SRST 4619``-option-rom file`` 4620 Load the contents of file as an option ROM. This option is useful to 4621 load things like EtherBoot. 4622ERST 4623 4624DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4625 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4626 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4627 QEMU_ARCH_ALL) 4628 4629SRST 4630``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4631 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4632 the current UTC or local time, respectively. ``localtime`` is 4633 required for correct date in MS-DOS or Windows. To start at a 4634 specific point in time, provide datetime in the format 4635 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4636 4637 By default the RTC is driven by the host system time. This allows 4638 using of the RTC as accurate reference clock inside the guest, 4639 specifically if the host time is smoothly following an accurate 4640 external reference clock, e.g. via NTP. If you want to isolate the 4641 guest time from the host, you can set ``clock`` to ``rt`` instead, 4642 which provides a host monotonic clock if host support it. To even 4643 prevent the RTC from progressing during suspension, you can set 4644 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4645 recommended especially in icount mode in order to preserve 4646 determinism; however, note that in icount mode the speed of the 4647 virtual clock is variable and can in general differ from the host 4648 clock. 4649 4650 Enable ``driftfix`` (i386 targets only) if you experience time drift 4651 problems, specifically with Windows' ACPI HAL. This option will try 4652 to figure out how many timer interrupts were not processed by the 4653 Windows guest and will re-inject them. 4654ERST 4655 4656DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4657 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4658 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4659 " instruction, enable aligning the host and virtual clocks\n" \ 4660 " or disable real time cpu sleeping, and optionally enable\n" \ 4661 " record-and-replay mode\n", QEMU_ARCH_ALL) 4662SRST 4663``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4664 Enable virtual instruction counter. The virtual cpu will execute one 4665 instruction every 2^N ns of virtual time. If ``auto`` is specified 4666 then the virtual cpu speed will be automatically adjusted to keep 4667 virtual time within a few seconds of real time. 4668 4669 Note that while this option can give deterministic behavior, it does 4670 not provide cycle accurate emulation. Modern CPUs contain 4671 superscalar out of order cores with complex cache hierarchies. The 4672 number of instructions executed often has little or no correlation 4673 with actual performance. 4674 4675 When the virtual cpu is sleeping, the virtual time will advance at 4676 default speed unless ``sleep=on`` is specified. With 4677 ``sleep=on``, the virtual time will jump to the next timer 4678 deadline instantly whenever the virtual cpu goes to sleep mode and 4679 will not advance if no timer is enabled. This behavior gives 4680 deterministic execution times from the guest point of view. 4681 The default if icount is enabled is ``sleep=off``. 4682 ``sleep=on`` cannot be used together with either ``shift=auto`` 4683 or ``align=on``. 4684 4685 ``align=on`` will activate the delay algorithm which will try to 4686 synchronise the host clock and the virtual clock. The goal is to 4687 have a guest running at the real frequency imposed by the shift 4688 option. Whenever the guest clock is behind the host clock and if 4689 ``align=on`` is specified then we print a message to the user to 4690 inform about the delay. Currently this option does not work when 4691 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4692 shift values for which the guest clock runs ahead of the host clock. 4693 Typically this happens when the shift value is high (how high 4694 depends on the host machine). The default if icount is enabled 4695 is ``align=off``. 4696 4697 When the ``rr`` option is specified deterministic record/replay is 4698 enabled. The ``rrfile=`` option must also be provided to 4699 specify the path to the replay log. In record mode data is written 4700 to this file, and in replay mode it is read back. 4701 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4702 name. In record mode, a new VM snapshot with the given name is created 4703 at the start of execution recording. In replay mode this option 4704 specifies the snapshot name used to load the initial VM state. 4705ERST 4706 4707DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4708 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4709 " action when watchdog fires [default=reset]\n", 4710 QEMU_ARCH_ALL) 4711SRST 4712``-watchdog-action action`` 4713 The action controls what QEMU will do when the watchdog timer 4714 expires. The default is ``reset`` (forcefully reset the guest). 4715 Other possible actions are: ``shutdown`` (attempt to gracefully 4716 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4717 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4718 guest), ``debug`` (print a debug message and continue), or ``none`` 4719 (do nothing). 4720 4721 Note that the ``shutdown`` action requires that the guest responds 4722 to ACPI signals, which it may not be able to do in the sort of 4723 situations where the watchdog would have expired, and thus 4724 ``-watchdog-action shutdown`` is not recommended for production use. 4725 4726 Examples: 4727 4728 ``-device i6300esb -watchdog-action pause`` 4729 4730ERST 4731 4732DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4733 "-echr chr set terminal escape character instead of ctrl-a\n", 4734 QEMU_ARCH_ALL) 4735SRST 4736``-echr numeric_ascii_value`` 4737 Change the escape character used for switching to the monitor when 4738 using monitor and serial sharing. The default is ``0x01`` when using 4739 the ``-nographic`` option. ``0x01`` is equal to pressing 4740 ``Control-a``. You can select a different character from the ascii 4741 control keys where 1 through 26 map to Control-a through Control-z. 4742 For instance you could use the either of the following to change the 4743 escape character to Control-t. 4744 4745 ``-echr 0x14``; \ ``-echr 20`` 4746 4747ERST 4748 4749DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4750 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4751 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4752 "-incoming unix:socketpath\n" \ 4753 " prepare for incoming migration, listen on\n" \ 4754 " specified protocol and socket address\n" \ 4755 "-incoming fd:fd\n" \ 4756 "-incoming file:filename[,offset=offset]\n" \ 4757 "-incoming exec:cmdline\n" \ 4758 " accept incoming migration on given file descriptor\n" \ 4759 " or from given external command\n" \ 4760 "-incoming defer\n" \ 4761 " wait for the URI to be specified via migrate_incoming\n", 4762 QEMU_ARCH_ALL) 4763SRST 4764``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4765 \ 4766``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4767 Prepare for incoming migration, listen on a given tcp port. 4768 4769``-incoming unix:socketpath`` 4770 Prepare for incoming migration, listen on a given unix socket. 4771 4772``-incoming fd:fd`` 4773 Accept incoming migration from a given file descriptor. 4774 4775``-incoming file:filename[,offset=offset]`` 4776 Accept incoming migration from a given file starting at offset. 4777 offset allows the common size suffixes, or a 0x prefix, but not both. 4778 4779``-incoming exec:cmdline`` 4780 Accept incoming migration as an output from specified external 4781 command. 4782 4783``-incoming defer`` 4784 Wait for the URI to be specified via migrate\_incoming. The monitor 4785 can be used to change settings (such as migration parameters) prior 4786 to issuing the migrate\_incoming to allow the migration to begin. 4787ERST 4788 4789DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4790 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4791SRST 4792``-only-migratable`` 4793 Only allow migratable devices. Devices will not be allowed to enter 4794 an unmigratable state. 4795ERST 4796 4797DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4798 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4799SRST 4800``-nodefaults`` 4801 Don't create default devices. Normally, QEMU sets the default 4802 devices like serial port, parallel port, virtual console, monitor 4803 device, VGA adapter, floppy and CD-ROM drive and others. The 4804 ``-nodefaults`` option will disable all those default devices. 4805ERST 4806 4807#ifndef _WIN32 4808DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4809 "-runas user change to user id user just before starting the VM\n" \ 4810 " user can be numeric uid:gid instead\n", 4811 QEMU_ARCH_ALL) 4812#endif 4813SRST 4814``-runas user`` 4815 Immediately before starting guest execution, drop root privileges, 4816 switching to the specified user. 4817ERST 4818 4819DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4820 "-prom-env variable=value\n" 4821 " set OpenBIOS nvram variables\n", 4822 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4823SRST 4824``-prom-env variable=value`` 4825 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4826 4827 :: 4828 4829 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4830 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4831 4832 :: 4833 4834 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4835 -prom-env 'boot-device=hd:2,\yaboot' \ 4836 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4837ERST 4838DEF("semihosting", 0, QEMU_OPTION_semihosting, 4839 "-semihosting semihosting mode\n", 4840 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4841 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4842SRST 4843``-semihosting`` 4844 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4845 4846 .. warning:: 4847 Note that this allows guest direct access to the host filesystem, so 4848 should only be used with a trusted guest OS. 4849 4850 See the -semihosting-config option documentation for further 4851 information about the facilities this enables. 4852ERST 4853DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4854 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4855 " semihosting configuration\n", 4856QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4857QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4858SRST 4859``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4860 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4861 only). 4862 4863 .. warning:: 4864 Note that this allows guest direct access to the host filesystem, so 4865 should only be used with a trusted guest OS. 4866 4867 ``target=native|gdb|auto`` 4868 Defines where the semihosting calls will be addressed, to QEMU 4869 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4870 means ``gdb`` during debug sessions and ``native`` otherwise. 4871 4872 ``chardev=str1`` 4873 Send the output to a chardev backend output for native or auto 4874 output when not in gdb 4875 4876 ``userspace=on|off`` 4877 Allows code running in guest userspace to access the semihosting 4878 interface. The default is that only privileged guest code can 4879 make semihosting calls. Note that setting ``userspace=on`` should 4880 only be used if all guest code is trusted (for example, in 4881 bare-metal test case code). 4882 4883 ``arg=str1,arg=str2,...`` 4884 Allows the user to pass input arguments, and can be used 4885 multiple times to build up a list. The old-style 4886 ``-kernel``/``-append`` method of passing a command line is 4887 still supported for backward compatibility. If both the 4888 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4889 specified, the former is passed to semihosting as it always 4890 takes precedence. 4891ERST 4892DEF("old-param", 0, QEMU_OPTION_old_param, 4893 "-old-param old param mode\n", QEMU_ARCH_ARM) 4894SRST 4895``-old-param`` 4896 Old param mode (ARM only). 4897ERST 4898 4899DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4900 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4901 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4902 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4903 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4904 " by the kernel, but typically no longer used by modern\n" \ 4905 " C library implementations.\n" \ 4906 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4907 " to elevate privileges using set*uid|gid system calls.\n" \ 4908 " The value 'children' will deny set*uid|gid system calls for\n" \ 4909 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4910 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4911 " blocking *fork and execve\n" \ 4912 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4913 QEMU_ARCH_ALL) 4914SRST 4915``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4916 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4917 filtering and 'off' will disable it. The default is 'off'. 4918 4919 ``obsolete=string`` 4920 Enable Obsolete system calls 4921 4922 ``elevateprivileges=string`` 4923 Disable set\*uid\|gid system calls 4924 4925 ``spawn=string`` 4926 Disable \*fork and execve 4927 4928 ``resourcecontrol=string`` 4929 Disable process affinity and schedular priority 4930ERST 4931 4932DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4933 "-readconfig <file>\n" 4934 " read config file\n", QEMU_ARCH_ALL) 4935SRST 4936``-readconfig file`` 4937 Read device configuration from file. This approach is useful when 4938 you want to spawn QEMU process with many command line options but 4939 you don't want to exceed the command line character limit. 4940ERST 4941 4942DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4943 "-no-user-config\n" 4944 " do not load default user-provided config files at startup\n", 4945 QEMU_ARCH_ALL) 4946SRST 4947``-no-user-config`` 4948 The ``-no-user-config`` option makes QEMU not load any of the 4949 user-provided config files on sysconfdir. 4950ERST 4951 4952DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4953 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4954 " specify tracing options\n", 4955 QEMU_ARCH_ALL) 4956SRST 4957``-trace [[enable=]pattern][,events=file][,file=file]`` 4958 .. include:: ../qemu-option-trace.rst.inc 4959 4960ERST 4961DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4962 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4963 " load a plugin\n", 4964 QEMU_ARCH_ALL) 4965SRST 4966``-plugin file=file[,argname=argvalue]`` 4967 Load a plugin. 4968 4969 ``file=file`` 4970 Load the given plugin from a shared library file. 4971 4972 ``argname=argvalue`` 4973 Argument passed to the plugin. (Can be given multiple times.) 4974ERST 4975 4976HXCOMM Internal use 4977DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4978DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4979 4980#ifdef CONFIG_POSIX 4981DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4982 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4983 " Set miscellaneous QEMU process lifecycle options:\n" 4984 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4985 " chroot=dir chroot to dir just before starting the VM\n", 4986 QEMU_ARCH_ALL) 4987SRST 4988``-run-with [async-teardown=on|off][,chroot=dir]`` 4989 Set QEMU process lifecycle options. 4990 4991 ``async-teardown=on`` enables asynchronous teardown. A new process called 4992 "cleanup/<QEMU_PID>" will be created at startup sharing the address 4993 space with the main QEMU process, using clone. It will wait for the 4994 main QEMU process to terminate completely, and then exit. This allows 4995 QEMU to terminate very quickly even if the guest was huge, leaving the 4996 teardown of the address space to the cleanup process. Since the cleanup 4997 process shares the same cgroups as the main QEMU process, accounting is 4998 performed correctly. This only works if the cleanup process is not 4999 forcefully killed with SIGKILL before the main QEMU process has 5000 terminated completely. 5001 5002 ``chroot=dir`` can be used for doing a chroot to the specified directory 5003 immediately before starting the guest execution. This is especially useful 5004 in combination with -runas. 5005ERST 5006#endif 5007 5008DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5009 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5010 " control error message format\n" 5011 " timestamp=on enables timestamps (default: off)\n" 5012 " guest-name=on enables guest name prefix but only if\n" 5013 " -name guest option is set (default: off)\n", 5014 QEMU_ARCH_ALL) 5015SRST 5016``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5017 Control error message format. 5018 5019 ``timestamp=on|off`` 5020 Prefix messages with a timestamp. Default is off. 5021 5022 ``guest-name=on|off`` 5023 Prefix messages with guest name but only if -name guest option is set 5024 otherwise the option is ignored. Default is off. 5025ERST 5026 5027DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5028 "-dump-vmstate <file>\n" 5029 " Output vmstate information in JSON format to file.\n" 5030 " Use the scripts/vmstate-static-checker.py file to\n" 5031 " check for possible regressions in migration code\n" 5032 " by comparing two such vmstate dumps.\n", 5033 QEMU_ARCH_ALL) 5034SRST 5035``-dump-vmstate file`` 5036 Dump json-encoded vmstate information for current machine type to 5037 file in file 5038ERST 5039 5040DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5041 "-enable-sync-profile\n" 5042 " enable synchronization profiling\n", 5043 QEMU_ARCH_ALL) 5044SRST 5045``-enable-sync-profile`` 5046 Enable synchronization profiling. 5047ERST 5048 5049#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5050DEF("perfmap", 0, QEMU_OPTION_perfmap, 5051 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5052 QEMU_ARCH_ALL) 5053SRST 5054``-perfmap`` 5055 Generate a map file for Linux perf tools that will allow basic profiling 5056 information to be broken down into basic blocks. 5057ERST 5058 5059DEF("jitdump", 0, QEMU_OPTION_jitdump, 5060 "-jitdump generate a jit-${pid}.dump file for perf\n", 5061 QEMU_ARCH_ALL) 5062SRST 5063``-jitdump`` 5064 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5065 names, line numbers and JITted code. 5066ERST 5067#endif 5068 5069DEFHEADING() 5070 5071DEFHEADING(Generic object creation:) 5072 5073DEF("object", HAS_ARG, QEMU_OPTION_object, 5074 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5075 " create a new object of type TYPENAME setting properties\n" 5076 " in the order they are specified. Note that the 'id'\n" 5077 " property must be set. These objects are placed in the\n" 5078 " '/objects' path.\n", 5079 QEMU_ARCH_ALL) 5080SRST 5081``-object typename[,prop1=value1,...]`` 5082 Create a new object of type typename setting properties in the order 5083 they are specified. Note that the 'id' property must be set. These 5084 objects are placed in the '/objects' path. 5085 5086 ``-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`` 5087 Creates a memory file backend object, which can be used to back 5088 the guest RAM with huge pages. 5089 5090 The ``id`` parameter is a unique ID that will be used to 5091 reference this memory region in other parameters, e.g. ``-numa``, 5092 ``-device nvdimm``, etc. 5093 5094 The ``size`` option provides the size of the memory region, and 5095 accepts common suffixes, e.g. ``500M``. 5096 5097 The ``mem-path`` provides the path to either a shared memory or 5098 huge page filesystem mount. 5099 5100 The ``share`` boolean option determines whether the memory 5101 region is marked as private to QEMU, or shared. The latter 5102 allows a co-operating external process to access the QEMU memory 5103 region. 5104 5105 The ``share`` is also required for pvrdma devices due to 5106 limitations in the RDMA API provided by Linux. 5107 5108 Setting share=on might affect the ability to configure NUMA 5109 bindings for the memory backend under some circumstances, see 5110 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5111 source tree for additional details. 5112 5113 Setting the ``discard-data`` boolean option to on indicates that 5114 file contents can be destroyed when QEMU exits, to avoid 5115 unnecessarily flushing data to the backing file. Note that 5116 ``discard-data`` is only an optimization, and QEMU might not 5117 discard file contents if it aborts unexpectedly or is terminated 5118 using SIGKILL. 5119 5120 The ``merge`` boolean option enables memory merge, also known as 5121 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5122 the pages for memory deduplication. 5123 5124 Setting the ``dump`` boolean option to off excludes the memory 5125 from core dumps. This feature is also known as MADV\_DONTDUMP. 5126 5127 The ``prealloc`` boolean option enables memory preallocation. 5128 5129 The ``host-nodes`` option binds the memory range to a list of 5130 NUMA host nodes. 5131 5132 The ``policy`` option sets the NUMA policy to one of the 5133 following values: 5134 5135 ``default`` 5136 default host policy 5137 5138 ``preferred`` 5139 prefer the given host node list for allocation 5140 5141 ``bind`` 5142 restrict memory allocation to the given host node list 5143 5144 ``interleave`` 5145 interleave memory allocations across the given host node 5146 list 5147 5148 The ``align`` option specifies the base address alignment when 5149 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5150 ``2M``. Some backend store specified by ``mem-path`` requires an 5151 alignment different than the default one used by QEMU, eg the 5152 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5153 such cases, users can specify the required alignment via this 5154 option. 5155 5156 The ``offset`` option specifies the offset into the target file 5157 that the region starts at. You can use this parameter to back 5158 multiple regions with a single file. 5159 5160 The ``pmem`` option specifies whether the backing file specified 5161 by ``mem-path`` is in host persistent memory that can be 5162 accessed using the SNIA NVM programming model (e.g. Intel 5163 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5164 operations to guarantee the persistence of its own writes to 5165 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5166 migration). Also, we will map the backend-file with MAP\_SYNC 5167 flag, which ensures the file metadata is in sync for 5168 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5169 requires support from both the host kernel (since Linux kernel 5170 4.15) and the filesystem of ``mem-path`` mounted with DAX 5171 option. 5172 5173 The ``readonly`` option specifies whether the backing file is opened 5174 read-only or read-write (default). 5175 5176 The ``rom`` option specifies whether to create Read Only Memory 5177 (ROM) that cannot be modified by the VM. Any write attempts to such 5178 ROM will be denied. Most use cases want proper RAM instead of ROM. 5179 However, selected use cases, like R/O NVDIMMs, can benefit from 5180 ROM. If set to ``on``, create ROM; if set to ``off``, create 5181 writable RAM; if set to ``auto`` (default), the value of the 5182 ``readonly`` option is used. This option is primarily helpful when 5183 we want to have writable RAM in configurations that would 5184 traditionally create ROM before the ``rom`` option was introduced: 5185 VM templating, where we want to open a file readonly 5186 (``readonly=on``) and mark the memory to be private for QEMU 5187 (``share=off``). For this use case, we need writable RAM instead 5188 of ROM, and want to also set ``rom=off``. 5189 5190 ``-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`` 5191 Creates a memory backend object, which can be used to back the 5192 guest RAM. Memory backend objects offer more control than the 5193 ``-m`` option that is traditionally used to define guest RAM. 5194 Please refer to ``memory-backend-file`` for a description of the 5195 options. 5196 5197 ``-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`` 5198 Creates an anonymous memory file backend object, which allows 5199 QEMU to share the memory with an external process (e.g. when 5200 using vhost-user). The memory is allocated with memfd and 5201 optional sealing. (Linux only) 5202 5203 The ``seal`` option creates a sealed-file, that will block 5204 further resizing the memory ('on' by default). 5205 5206 The ``hugetlb`` option specify the file to be created resides in 5207 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5208 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5209 the hugetlb page size on systems that support multiple hugetlb 5210 page sizes (it must be a power of 2 value supported by the 5211 system). 5212 5213 In some versions of Linux, the ``hugetlb`` option is 5214 incompatible with the ``seal`` option (requires at least Linux 5215 4.16). 5216 5217 Please refer to ``memory-backend-file`` for a description of the 5218 other options. 5219 5220 The ``share`` boolean option is on by default with memfd. 5221 5222 ``-object iommufd,id=id[,fd=fd]`` 5223 Creates an iommufd backend which allows control of DMA mapping 5224 through the ``/dev/iommu`` device. 5225 5226 The ``id`` parameter is a unique ID which frontends (such as 5227 vfio-pci of vdpa) will use to connect with the iommufd backend. 5228 5229 The ``fd`` parameter is an optional pre-opened file descriptor 5230 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5231 across all subsystems, bringing the benefit of centralized 5232 reference counting. 5233 5234 ``-object rng-builtin,id=id`` 5235 Creates a random number generator backend which obtains entropy 5236 from QEMU builtin functions. The ``id`` parameter is a unique ID 5237 that will be used to reference this entropy backend from the 5238 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5239 uses this RNG backend. 5240 5241 ``-object rng-random,id=id,filename=/dev/random`` 5242 Creates a random number generator backend which obtains entropy 5243 from a device on the host. The ``id`` parameter is a unique ID 5244 that will be used to reference this entropy backend from the 5245 ``virtio-rng`` device. The ``filename`` parameter specifies 5246 which file to obtain entropy from and if omitted defaults to 5247 ``/dev/urandom``. 5248 5249 ``-object rng-egd,id=id,chardev=chardevid`` 5250 Creates a random number generator backend which obtains entropy 5251 from an external daemon running on the host. The ``id`` 5252 parameter is a unique ID that will be used to reference this 5253 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5254 parameter is the unique ID of a character device backend that 5255 provides the connection to the RNG daemon. 5256 5257 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5258 Creates a TLS anonymous credentials object, which can be used to 5259 provide TLS support on network backends. The ``id`` parameter is 5260 a unique ID which network backends will use to access the 5261 credentials. The ``endpoint`` is either ``server`` or ``client`` 5262 depending on whether the QEMU network backend that uses the 5263 credentials will be acting as a client or as a server. If 5264 ``verify-peer`` is enabled (the default) then once the handshake 5265 is completed, the peer credentials will be verified, though this 5266 is a no-op for anonymous credentials. 5267 5268 The dir parameter tells QEMU where to find the credential files. 5269 For server endpoints, this directory may contain a file 5270 dh-params.pem providing diffie-hellman parameters to use for the 5271 TLS server. If the file is missing, QEMU will generate a set of 5272 DH parameters at startup. This is a computationally expensive 5273 operation that consumes random pool entropy, so it is 5274 recommended that a persistent set of parameters be generated 5275 upfront and saved. 5276 5277 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5278 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5279 can be used to provide TLS support on network backends. The 5280 ``id`` parameter is a unique ID which network backends will use 5281 to access the credentials. The ``endpoint`` is either ``server`` 5282 or ``client`` depending on whether the QEMU network backend that 5283 uses the credentials will be acting as a client or as a server. 5284 For clients only, ``username`` is the username which will be 5285 sent to the server. If omitted it defaults to "qemu". 5286 5287 The dir parameter tells QEMU where to find the keys file. It is 5288 called "dir/keys.psk" and contains "username:key" pairs. This 5289 file can most easily be created using the GnuTLS ``psktool`` 5290 program. 5291 5292 For server endpoints, dir may also contain a file dh-params.pem 5293 providing diffie-hellman parameters to use for the TLS server. 5294 If the file is missing, QEMU will generate a set of DH 5295 parameters at startup. This is a computationally expensive 5296 operation that consumes random pool entropy, so it is 5297 recommended that a persistent set of parameters be generated up 5298 front and saved. 5299 5300 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5301 Creates a TLS anonymous credentials object, which can be used to 5302 provide TLS support on network backends. The ``id`` parameter is 5303 a unique ID which network backends will use to access the 5304 credentials. The ``endpoint`` is either ``server`` or ``client`` 5305 depending on whether the QEMU network backend that uses the 5306 credentials will be acting as a client or as a server. If 5307 ``verify-peer`` is enabled (the default) then once the handshake 5308 is completed, the peer credentials will be verified. With x509 5309 certificates, this implies that the clients must be provided 5310 with valid client certificates too. 5311 5312 The dir parameter tells QEMU where to find the credential files. 5313 For server endpoints, this directory may contain a file 5314 dh-params.pem providing diffie-hellman parameters to use for the 5315 TLS server. If the file is missing, QEMU will generate a set of 5316 DH parameters at startup. This is a computationally expensive 5317 operation that consumes random pool entropy, so it is 5318 recommended that a persistent set of parameters be generated 5319 upfront and saved. 5320 5321 For x509 certificate credentials the directory will contain 5322 further files providing the x509 certificates. The certificates 5323 must be stored in PEM format, in filenames ca-cert.pem, 5324 ca-crl.pem (optional), server-cert.pem (only servers), 5325 server-key.pem (only servers), client-cert.pem (only clients), 5326 and client-key.pem (only clients). 5327 5328 For the server-key.pem and client-key.pem files which contain 5329 sensitive private keys, it is possible to use an encrypted 5330 version by providing the passwordid parameter. This provides the 5331 ID of a previously created ``secret`` object containing the 5332 password for decryption. 5333 5334 The priority parameter allows to override the global default 5335 priority used by gnutls. This can be useful if the system 5336 administrator needs to use a weaker set of crypto priorities for 5337 QEMU without potentially forcing the weakness onto all 5338 applications. Or conversely if one wants wants a stronger 5339 default for QEMU than for all other applications, they can do 5340 this through this parameter. Its format is a gnutls priority 5341 string as described at 5342 https://gnutls.org/manual/html_node/Priority-Strings.html. 5343 5344 ``-object tls-cipher-suites,id=id,priority=priority`` 5345 Creates a TLS cipher suites object, which can be used to control 5346 the TLS cipher/protocol algorithms that applications are permitted 5347 to use. 5348 5349 The ``id`` parameter is a unique ID which frontends will use to 5350 access the ordered list of permitted TLS cipher suites from the 5351 host. 5352 5353 The ``priority`` parameter allows to override the global default 5354 priority used by gnutls. This can be useful if the system 5355 administrator needs to use a weaker set of crypto priorities for 5356 QEMU without potentially forcing the weakness onto all 5357 applications. Or conversely if one wants wants a stronger 5358 default for QEMU than for all other applications, they can do 5359 this through this parameter. Its format is a gnutls priority 5360 string as described at 5361 https://gnutls.org/manual/html_node/Priority-Strings.html. 5362 5363 An example of use of this object is to control UEFI HTTPS Boot. 5364 The tls-cipher-suites object exposes the ordered list of permitted 5365 TLS cipher suites from the host side to the guest firmware, via 5366 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5367 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5368 guest-side TLS. 5369 5370 In the following example, the priority at which the host-side policy 5371 is retrieved is given by the ``priority`` property. 5372 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5373 refer to /etc/crypto-policies/back-ends/gnutls.config. 5374 5375 .. parsed-literal:: 5376 5377 # |qemu_system| \\ 5378 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5379 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5380 5381 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5382 Interval t can't be 0, this filter batches the packet delivery: 5383 all packets arriving in a given interval on netdev netdevid are 5384 delayed until the end of the interval. Interval is in 5385 microseconds. ``status`` is optional that indicate whether the 5386 netfilter is on (enabled) or off (disabled), the default status 5387 for netfilter will be 'on'. 5388 5389 queue all\|rx\|tx is an option that can be applied to any 5390 netfilter. 5391 5392 ``all``: the filter is attached both to the receive and the 5393 transmit queue of the netdev (default). 5394 5395 ``rx``: the filter is attached to the receive queue of the 5396 netdev, where it will receive packets sent to the netdev. 5397 5398 ``tx``: the filter is attached to the transmit queue of the 5399 netdev, where it will receive packets sent by the netdev. 5400 5401 position head\|tail\|id=<id> is an option to specify where the 5402 filter should be inserted in the filter list. It can be applied 5403 to any netfilter. 5404 5405 ``head``: the filter is inserted at the head of the filter list, 5406 before any existing filters. 5407 5408 ``tail``: the filter is inserted at the tail of the filter list, 5409 behind any existing filters (default). 5410 5411 ``id=<id>``: the filter is inserted before or behind the filter 5412 specified by <id>, see the insert option below. 5413 5414 insert behind\|before is an option to specify where to insert 5415 the new filter relative to the one specified with 5416 position=id=<id>. It can be applied to any netfilter. 5417 5418 ``before``: insert before the specified filter. 5419 5420 ``behind``: insert behind the specified filter (default). 5421 5422 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5423 filter-mirror on netdev netdevid,mirror net packet to 5424 chardevchardevid, if it has the vnet\_hdr\_support flag, 5425 filter-mirror will mirror packet with vnet\_hdr\_len. 5426 5427 ``-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]`` 5428 filter-redirector on netdev netdevid,redirect filter's net 5429 packet to chardev chardevid,and redirect indev's packet to 5430 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5431 will redirect packet with vnet\_hdr\_len. Create a 5432 filter-redirector we need to differ outdev id from indev id, id 5433 can not be the same. we can just use indev or outdev, but at 5434 least one of indev or outdev need to be specified. 5435 5436 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5437 Filter-rewriter is a part of COLO project.It will rewrite tcp 5438 packet to secondary from primary to keep secondary tcp 5439 connection,and rewrite tcp packet to primary from secondary make 5440 tcp packet can be handled by client.if it has the 5441 vnet\_hdr\_support flag, we can parse packet with vnet header. 5442 5443 usage: colo secondary: -object 5444 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5445 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5446 filter-rewriter,id=rew0,netdev=hn0,queue=all 5447 5448 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5449 Dump the network traffic on netdev dev to the file specified by 5450 filename. At most len bytes (64k by default) per packet are 5451 stored. The file format is libpcap, so it can be analyzed with 5452 tools such as tcpdump or Wireshark. 5453 5454 ``-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}]`` 5455 Colo-compare gets packet from primary\_in chardevid and 5456 secondary\_in, then compare whether the payload of primary packet 5457 and secondary packet are the same. If same, it will output 5458 primary packet to out\_dev, else it will notify COLO-framework to do 5459 checkpoint and send primary packet to out\_dev. In order to 5460 improve efficiency, we need to put the task of comparison in 5461 another iothread. If it has the vnet\_hdr\_support flag, 5462 colo compare will send/recv packet with vnet\_hdr\_len. 5463 The compare\_timeout=@var{ms} determines the maximum time of the 5464 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5465 is to set the period of scanning expired primary node network packets. 5466 The max\_queue\_size=@var{size} is to set the max compare queue 5467 size depend on user environment. 5468 If user want to use Xen COLO, need to add the notify\_dev to 5469 notify Xen colo-frame to do checkpoint. 5470 5471 COLO-compare must be used with the help of filter-mirror, 5472 filter-redirector and filter-rewriter. 5473 5474 :: 5475 5476 KVM COLO 5477 5478 primary: 5479 -netdev tap,id=hn0,vhost=off 5480 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5481 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5482 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5483 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5484 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5485 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5486 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5487 -object iothread,id=iothread1 5488 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5489 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5490 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5491 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5492 5493 secondary: 5494 -netdev tap,id=hn0,vhost=off 5495 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5496 -chardev socket,id=red0,host=3.3.3.3,port=9003 5497 -chardev socket,id=red1,host=3.3.3.3,port=9004 5498 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5499 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5500 5501 5502 Xen COLO 5503 5504 primary: 5505 -netdev tap,id=hn0,vhost=off 5506 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5507 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5508 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5509 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5510 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5511 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5512 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5513 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5514 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5515 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5516 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5517 -object iothread,id=iothread1 5518 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5519 5520 secondary: 5521 -netdev tap,id=hn0,vhost=off 5522 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5523 -chardev socket,id=red0,host=3.3.3.3,port=9003 5524 -chardev socket,id=red1,host=3.3.3.3,port=9004 5525 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5526 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5527 5528 If you want to know the detail of above command line, you can 5529 read the colo-compare git log. 5530 5531 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5532 Creates a cryptodev backend which executes crypto operations from 5533 the QEMU cipher APIs. The id parameter is a unique ID that will 5534 be used to reference this cryptodev backend from the 5535 ``virtio-crypto`` device. The queues parameter is optional, 5536 which specify the queue number of cryptodev backend, the default 5537 of queues is 1. 5538 5539 .. parsed-literal:: 5540 5541 # |qemu_system| \\ 5542 [...] \\ 5543 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5544 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5545 [...] 5546 5547 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5548 Creates a vhost-user cryptodev backend, backed by a chardev 5549 chardevid. The id parameter is a unique ID that will be used to 5550 reference this cryptodev backend from the ``virtio-crypto`` 5551 device. The chardev should be a unix domain socket backed one. 5552 The vhost-user uses a specifically defined protocol to pass 5553 vhost ioctl replacement messages to an application on the other 5554 end of the socket. The queues parameter is optional, which 5555 specify the queue number of cryptodev backend for multiqueue 5556 vhost-user, the default of queues is 1. 5557 5558 .. parsed-literal:: 5559 5560 # |qemu_system| \\ 5561 [...] \\ 5562 -chardev socket,id=chardev0,path=/path/to/socket \\ 5563 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5564 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5565 [...] 5566 5567 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5568 \ 5569 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5570 Defines a secret to store a password, encryption key, or some 5571 other sensitive data. The sensitive data can either be passed 5572 directly via the data parameter, or indirectly via the file 5573 parameter. Using the data parameter is insecure unless the 5574 sensitive data is encrypted. 5575 5576 The sensitive data can be provided in raw format (the default), 5577 or base64. When encoded as JSON, the raw format only supports 5578 valid UTF-8 characters, so base64 is recommended for sending 5579 binary data. QEMU will convert from which ever format is 5580 provided to the format it needs internally. eg, an RBD password 5581 can be provided in raw format, even though it will be base64 5582 encoded when passed onto the RBD sever. 5583 5584 For added protection, it is possible to encrypt the data 5585 associated with a secret using the AES-256-CBC cipher. Use of 5586 encryption is indicated by providing the keyid and iv 5587 parameters. The keyid parameter provides the ID of a previously 5588 defined secret that contains the AES-256 decryption key. This 5589 key should be 32-bytes long and be base64 encoded. The iv 5590 parameter provides the random initialization vector used for 5591 encryption of this particular secret and should be a base64 5592 encrypted string of the 16-byte IV. 5593 5594 The simplest (insecure) usage is to provide the secret inline 5595 5596 .. parsed-literal:: 5597 5598 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5599 5600 The simplest secure usage is to provide the secret via a file 5601 5602 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5603 secret,id=sec0,file=mypasswd.txt,format=raw 5604 5605 For greater security, AES-256-CBC should be used. To illustrate 5606 usage, consider the openssl command line tool which can encrypt 5607 the data. Note that when encrypting, the plaintext must be 5608 padded to the cipher block size (32 bytes) using the standard 5609 PKCS#5/6 compatible padding algorithm. 5610 5611 First a master key needs to be created in base64 encoding: 5612 5613 :: 5614 5615 # openssl rand -base64 32 > key.b64 5616 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5617 5618 Each secret to be encrypted needs to have a random 5619 initialization vector generated. These do not need to be kept 5620 secret 5621 5622 :: 5623 5624 # openssl rand -base64 16 > iv.b64 5625 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5626 5627 The secret to be defined can now be encrypted, in this case 5628 we're telling openssl to base64 encode the result, but it could 5629 be left as raw bytes if desired. 5630 5631 :: 5632 5633 # SECRET=$(printf "letmein" | 5634 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5635 5636 When launching QEMU, create a master secret pointing to 5637 ``key.b64`` and specify that to be used to decrypt the user 5638 password. Pass the contents of ``iv.b64`` to the second secret 5639 5640 .. parsed-literal:: 5641 5642 # |qemu_system| \\ 5643 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5644 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5645 data=$SECRET,iv=$(<iv.b64) 5646 5647 ``-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]`` 5648 Create a Secure Encrypted Virtualization (SEV) guest object, 5649 which can be used to provide the guest memory encryption support 5650 on AMD processors. 5651 5652 When memory encryption is enabled, one of the physical address 5653 bit (aka the C-bit) is utilized to mark if a memory page is 5654 protected. The ``cbitpos`` is used to provide the C-bit 5655 position. The C-bit position is Host family dependent hence user 5656 must provide this value. On EPYC, the value should be 47. 5657 5658 When memory encryption is enabled, we loose certain bits in 5659 physical address space. The ``reduced-phys-bits`` is used to 5660 provide the number of bits we loose in physical address space. 5661 Similar to C-bit, the value is Host family dependent. On EPYC, 5662 a guest will lose a maximum of 1 bit, so the value should be 1. 5663 5664 The ``sev-device`` provides the device file to use for 5665 communicating with the SEV firmware running inside AMD Secure 5666 Processor. The default device is '/dev/sev'. If hardware 5667 supports memory encryption then /dev/sev devices are created by 5668 CCP driver. 5669 5670 The ``policy`` provides the guest policy to be enforced by the 5671 SEV firmware and restrict what configuration and operational 5672 commands can be performed on this guest by the hypervisor. The 5673 policy should be provided by the guest owner and is bound to the 5674 guest and cannot be changed throughout the lifetime of the 5675 guest. The default is 0. 5676 5677 If guest ``policy`` allows sharing the key with another SEV 5678 guest then ``handle`` can be use to provide handle of the guest 5679 from which to share the key. 5680 5681 The ``dh-cert-file`` and ``session-file`` provides the guest 5682 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5683 and session parameters are used for establishing a cryptographic 5684 session with the guest owner to negotiate keys used for 5685 attestation. The file must be encoded in base64. 5686 5687 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5688 cmdline to a designated guest firmware page for measured Linux 5689 boot with -kernel. The default is off. (Since 6.2) 5690 5691 e.g to launch a SEV guest 5692 5693 .. parsed-literal:: 5694 5695 # |qemu_system_x86| \\ 5696 ...... \\ 5697 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5698 -machine ...,memory-encryption=sev0 \\ 5699 ..... 5700 5701 ``-object authz-simple,id=id,identity=string`` 5702 Create an authorization object that will control access to 5703 network services. 5704 5705 The ``identity`` parameter is identifies the user and its format 5706 depends on the network service that authorization object is 5707 associated with. For authorizing based on TLS x509 certificates, 5708 the identity must be the x509 distinguished name. Note that care 5709 must be taken to escape any commas in the distinguished name. 5710 5711 An example authorization object to validate a x509 distinguished 5712 name would look like: 5713 5714 .. parsed-literal:: 5715 5716 # |qemu_system| \\ 5717 ... \\ 5718 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5719 ... 5720 5721 Note the use of quotes due to the x509 distinguished name 5722 containing whitespace, and escaping of ','. 5723 5724 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5725 Create an authorization object that will control access to 5726 network services. 5727 5728 The ``filename`` parameter is the fully qualified path to a file 5729 containing the access control list rules in JSON format. 5730 5731 An example set of rules that match against SASL usernames might 5732 look like: 5733 5734 :: 5735 5736 { 5737 "rules": [ 5738 { "match": "fred", "policy": "allow", "format": "exact" }, 5739 { "match": "bob", "policy": "allow", "format": "exact" }, 5740 { "match": "danb", "policy": "deny", "format": "glob" }, 5741 { "match": "dan*", "policy": "allow", "format": "exact" }, 5742 ], 5743 "policy": "deny" 5744 } 5745 5746 When checking access the object will iterate over all the rules 5747 and the first rule to match will have its ``policy`` value 5748 returned as the result. If no rules match, then the default 5749 ``policy`` value is returned. 5750 5751 The rules can either be an exact string match, or they can use 5752 the simple UNIX glob pattern matching to allow wildcards to be 5753 used. 5754 5755 If ``refresh`` is set to true the file will be monitored and 5756 automatically reloaded whenever its content changes. 5757 5758 As with the ``authz-simple`` object, the format of the identity 5759 strings being matched depends on the network service, but is 5760 usually a TLS x509 distinguished name, or a SASL username. 5761 5762 An example authorization object to validate a SASL username 5763 would look like: 5764 5765 .. parsed-literal:: 5766 5767 # |qemu_system| \\ 5768 ... \\ 5769 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5770 ... 5771 5772 ``-object authz-pam,id=id,service=string`` 5773 Create an authorization object that will control access to 5774 network services. 5775 5776 The ``service`` parameter provides the name of a PAM service to 5777 use for authorization. It requires that a file 5778 ``/etc/pam.d/service`` exist to provide the configuration for 5779 the ``account`` subsystem. 5780 5781 An example authorization object to validate a TLS x509 5782 distinguished name would look like: 5783 5784 .. parsed-literal:: 5785 5786 # |qemu_system| \\ 5787 ... \\ 5788 -object authz-pam,id=auth0,service=qemu-vnc \\ 5789 ... 5790 5791 There would then be a corresponding config file for PAM at 5792 ``/etc/pam.d/qemu-vnc`` that contains: 5793 5794 :: 5795 5796 account requisite pam_listfile.so item=user sense=allow \ 5797 file=/etc/qemu/vnc.allow 5798 5799 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5800 of x509 distinguished names that are permitted access 5801 5802 :: 5803 5804 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5805 5806 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5807 Creates a dedicated event loop thread that devices can be 5808 assigned to. This is known as an IOThread. By default device 5809 emulation happens in vCPU threads or the main event loop thread. 5810 This can become a scalability bottleneck. IOThreads allow device 5811 emulation and I/O to run on other host CPUs. 5812 5813 The ``id`` parameter is a unique ID that will be used to 5814 reference this IOThread from ``-device ...,iothread=id``. 5815 Multiple devices can be assigned to an IOThread. Note that not 5816 all devices support an ``iothread`` parameter. 5817 5818 The ``query-iothreads`` QMP command lists IOThreads and reports 5819 their thread IDs so that the user can configure host CPU 5820 pinning/affinity. 5821 5822 IOThreads use an adaptive polling algorithm to reduce event loop 5823 latency. Instead of entering a blocking system call to monitor 5824 file descriptors and then pay the cost of being woken up when an 5825 event occurs, the polling algorithm spins waiting for events for 5826 a short time. The algorithm's default parameters are suitable 5827 for many cases but can be adjusted based on knowledge of the 5828 workload and/or host device latency. 5829 5830 The ``poll-max-ns`` parameter is the maximum number of 5831 nanoseconds to busy wait for events. Polling can be disabled by 5832 setting this value to 0. 5833 5834 The ``poll-grow`` parameter is the multiplier used to increase 5835 the polling time when the algorithm detects it is missing events 5836 due to not polling long enough. 5837 5838 The ``poll-shrink`` parameter is the divisor used to decrease 5839 the polling time when the algorithm detects it is spending too 5840 long polling without encountering events. 5841 5842 The ``aio-max-batch`` parameter is the maximum number of requests 5843 in a batch for the AIO engine, 0 means that the engine will use 5844 its default. 5845 5846 The IOThread parameters can be modified at run-time using the 5847 ``qom-set`` command (where ``iothread1`` is the IOThread's 5848 ``id``): 5849 5850 :: 5851 5852 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5853ERST 5854 5855 5856HXCOMM This is the last statement. Insert new options before this line! 5857 5858#undef DEF 5859#undef DEFHEADING 5860#undef ARCHHEADING 5861