1HXCOMM See docs/devel/docs.rst for the format of this file. 2HXCOMM 3HXCOMM Use DEFHEADING() to define headings in both help text and rST. 4HXCOMM Text between SRST and ERST is copied to the rST version and 5HXCOMM discarded from C version. 6HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 7HXCOMM construct option structures, enums and help message for specified 8HXCOMM architectures. 9HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 10 11DEFHEADING(Standard options:) 12 13DEF("help", 0, QEMU_OPTION_h, 14 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 15SRST 16``-h`` 17 Display help and exit 18ERST 19 20DEF("version", 0, QEMU_OPTION_version, 21 "-version display version information and exit\n", QEMU_ARCH_ALL) 22SRST 23``-version`` 24 Display version information and exit 25ERST 26 27DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 28 "-machine [type=]name[,prop[=value][,...]]\n" 29 " selects emulated machine ('-machine help' for list)\n" 30 " property accel=accel1[:accel2[:...]] selects accelerator\n" 31 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 32 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 33 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 34 " mem-merge=on|off controls memory merge support (default: on)\n" 35 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 36 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 37 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 38 " nvdimm=on|off controls NVDIMM support (default=off)\n" 39 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 40 " hmat=on|off controls ACPI HMAT support (default=off)\n" 41 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 42 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 43 QEMU_ARCH_ALL) 44SRST 45``-machine [type=]name[,prop=value[,...]]`` 46 Select the emulated machine by name. Use ``-machine help`` to list 47 available machines. 48 49 For architectures which aim to support live migration compatibility 50 across releases, each release will introduce a new versioned machine 51 type. For example, the 2.8.0 release introduced machine types 52 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 53 54 To allow live migration of guests from QEMU version 2.8.0, to QEMU 55 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 56 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 57 skip multiple intermediate releases when upgrading, new releases of 58 QEMU will support machine types from many previous versions. 59 60 Supported machine properties are: 61 62 ``accel=accels1[:accels2[:...]]`` 63 This is used to enable an accelerator. Depending on the target 64 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 65 By default, tcg is used. If there is more than one accelerator 66 specified, the next one is used if the previous one fails to 67 initialize. 68 69 ``vmport=on|off|auto`` 70 Enables emulation of VMWare IO port, for vmmouse etc. auto says 71 to select the value based on accel. For accel=xen the default is 72 off otherwise the default is on. 73 74 ``dump-guest-core=on|off`` 75 Include guest memory in a core dump. The default is on. 76 77 ``mem-merge=on|off`` 78 Enables or disables memory merge support. This feature, when 79 supported by the host, de-duplicates identical memory pages 80 among VMs instances (enabled by default). 81 82 ``aes-key-wrap=on|off`` 83 Enables or disables AES key wrapping support on s390-ccw hosts. 84 This feature controls whether AES wrapping keys will be created 85 to allow execution of AES cryptographic functions. The default 86 is on. 87 88 ``dea-key-wrap=on|off`` 89 Enables or disables DEA key wrapping support on s390-ccw hosts. 90 This feature controls whether DEA wrapping keys will be created 91 to allow execution of DEA cryptographic functions. The default 92 is on. 93 94 ``nvdimm=on|off`` 95 Enables or disables NVDIMM support. The default is off. 96 97 ``memory-encryption=`` 98 Memory encryption object to use. The default is none. 99 100 ``hmat=on|off`` 101 Enables or disables ACPI Heterogeneous Memory Attribute Table 102 (HMAT) support. The default is off. 103 104 ``memory-backend='id'`` 105 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 106 Allows to use a memory backend as main RAM. 107 108 For example: 109 :: 110 111 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 112 -machine memory-backend=pc.ram 113 -m 512M 114 115 Migration compatibility note: 116 117 * as backend id one shall use value of 'default-ram-id', advertised by 118 machine type (available via ``query-machines`` QMP command), if migration 119 to/from old QEMU (<5.0) is expected. 120 * for machine types 4.0 and older, user shall 121 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 122 if migration to/from old QEMU (<5.0) is expected. 123 124 For example: 125 :: 126 127 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 128 -machine memory-backend=pc.ram 129 -m 512M 130 131 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 132 Define a CXL Fixed Memory Window (CFMW). 133 134 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 135 136 They are regions of Host Physical Addresses (HPA) on a system which 137 may be interleaved across one or more CXL host bridges. The system 138 software will assign particular devices into these windows and 139 configure the downstream Host-managed Device Memory (HDM) decoders 140 in root ports, switch ports and devices appropriately to meet the 141 interleave requirements before enabling the memory devices. 142 143 ``targets.X=target`` provides the mapping to CXL host bridges 144 which may be identified by the id provided in the -device entry. 145 Multiple entries are needed to specify all the targets when 146 the fixed memory window represents interleaved memory. X is the 147 target index from 0. 148 149 ``size=size`` sets the size of the CFMW. This must be a multiple of 150 256MiB. The region will be aligned to 256MiB but the location is 151 platform and configuration dependent. 152 153 ``interleave-granularity=granularity`` sets the granularity of 154 interleave. Default 256 (bytes). Only 256, 512, 1k, 2k, 155 4k, 8k and 16k granularities supported. 156 157 Example: 158 159 :: 160 161 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512 162ERST 163 164DEF("M", HAS_ARG, QEMU_OPTION_M, 165 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 166 QEMU_ARCH_ALL) 167 168SRST 169``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 170 Define an SGX EPC section. 171ERST 172 173DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 174 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 175SRST 176``-cpu model`` 177 Select CPU model (``-cpu help`` for list and additional feature 178 selection) 179ERST 180 181DEF("accel", HAS_ARG, QEMU_OPTION_accel, 182 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 183 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 184 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 185 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 186 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 187 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 188 " split-wx=on|off (enable TCG split w^x mapping)\n" 189 " tb-size=n (TCG translation block cache size)\n" 190 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 191 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 192 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 193 " thread=single|multi (enable multi-threaded TCG)\n" 194 " device=path (KVM device path, default /dev/kvm)\n", QEMU_ARCH_ALL) 195SRST 196``-accel name[,prop=value[,...]]`` 197 This is used to enable an accelerator. Depending on the target 198 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 199 default, tcg is used. If there is more than one accelerator 200 specified, the next one is used if the previous one fails to 201 initialize. 202 203 ``igd-passthru=on|off`` 204 When Xen is in use, this option controls whether Intel 205 integrated graphics devices can be passed through to the guest 206 (default=off) 207 208 ``kernel-irqchip=on|off|split`` 209 Controls KVM in-kernel irqchip support. The default is full 210 acceleration of the interrupt controllers. On x86, split irqchip 211 reduces the kernel attack surface, at a performance cost for 212 non-MSI interrupts. Disabling the in-kernel irqchip completely 213 is not recommended except for debugging purposes. 214 215 ``kvm-shadow-mem=size`` 216 Defines the size of the KVM shadow MMU. 217 218 ``one-insn-per-tb=on|off`` 219 Makes the TCG accelerator put only one guest instruction into 220 each translation block. This slows down emulation a lot, but 221 can be useful in some situations, such as when trying to analyse 222 the logs produced by the ``-d`` option. 223 224 ``split-wx=on|off`` 225 Controls the use of split w^x mapping for the TCG code generation 226 buffer. Some operating systems require this to be enabled, and in 227 such a case this will default on. On other operating systems, this 228 will default off, but one may enable this for testing or debugging. 229 230 ``tb-size=n`` 231 Controls the size (in MiB) of the TCG translation block cache. 232 233 ``thread=single|multi`` 234 Controls number of TCG threads. When the TCG is multi-threaded 235 there will be one thread per vCPU therefore taking advantage of 236 additional host cores. The default is to enable multi-threading 237 where both the back-end and front-ends support it and no 238 incompatible TCG features have been enabled (e.g. 239 icount/replay). 240 241 ``dirty-ring-size=n`` 242 When the KVM accelerator is used, it controls the size of the per-vCPU 243 dirty page ring buffer (number of entries for each vCPU). It should 244 be a value that is power of two, and it should be 1024 or bigger (but 245 still less than the maximum value that the kernel supports). 4096 246 could be a good initial value if you have no idea which is the best. 247 Set this value to 0 to disable the feature. By default, this feature 248 is disabled (dirty-ring-size=0). When enabled, KVM will instead 249 record dirty pages in a bitmap. 250 251 ``eager-split-size=n`` 252 KVM implements dirty page logging at the PAGE_SIZE granularity and 253 enabling dirty-logging on a huge-page requires breaking it into 254 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 255 lazily by default. There are performance benefits in doing huge-page 256 split eagerly, especially in situations where TLBI costs associated 257 with break-before-make sequences are considerable and also if guest 258 workloads are read intensive. The size here specifies how many pages 259 to break at a time and needs to be a valid block size which is 260 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 261 respectively. Be wary of specifying a higher size as it will have an 262 impact on the memory. By default, this feature is disabled 263 (eager-split-size=0). 264 265 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 266 Enables or disables notify VM exit support on x86 host and specify 267 the corresponding notify window to trigger the VM exit if enabled. 268 ``run`` option enables the feature. It does nothing and continue 269 if the exit happens. ``internal-error`` option enables the feature. 270 It raises a internal error. ``disable`` option doesn't enable the feature. 271 This feature can mitigate the CPU stuck issue due to event windows don't 272 open up for a specified of time (i.e. notify-window). 273 Default: notify-vmexit=run,notify-window=0. 274 275 ``device=path`` 276 Sets the path to the KVM device node. Defaults to ``/dev/kvm``. This 277 option can be used to pass the KVM device to use via a file descriptor 278 by setting the value to ``/dev/fdset/NN``. 279 280ERST 281 282DEF("smp", HAS_ARG, QEMU_OPTION_smp, 283 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 284 " [,dies=dies][,clusters=clusters][,modules=modules][,cores=cores]\n" 285 " [,threads=threads]\n" 286 " set the number of initial CPUs to 'n' [default=1]\n" 287 " maxcpus= maximum number of total CPUs, including\n" 288 " offline CPUs for hotplug, etc\n" 289 " drawers= number of drawers on the machine board\n" 290 " books= number of books in one drawer\n" 291 " sockets= number of sockets in one book\n" 292 " dies= number of dies in one socket\n" 293 " clusters= number of clusters in one die\n" 294 " modules= number of modules in one cluster\n" 295 " cores= number of cores in one module\n" 296 " threads= number of threads in one core\n" 297 "Note: Different machines may have different subsets of the CPU topology\n" 298 " parameters supported, so the actual meaning of the supported parameters\n" 299 " will vary accordingly. For example, for a machine type that supports a\n" 300 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 301 " sequentially mean as below:\n" 302 " sockets means the number of sockets on the machine board\n" 303 " cores means the number of cores in one socket\n" 304 " threads means the number of threads in one core\n" 305 " For a particular machine type board, an expected CPU topology hierarchy\n" 306 " can be defined through the supported sub-option. Unsupported parameters\n" 307 " can also be provided in addition to the sub-option, but their values\n" 308 " must be set as 1 in the purpose of correct parsing.\n", 309 QEMU_ARCH_ALL) 310SRST 311``-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets][,dies=dies][,clusters=clusters][,modules=modules][,cores=cores][,threads=threads]`` 312 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 313 the machine type board. On boards supporting CPU hotplug, the optional 314 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 315 added at runtime. When both parameters are omitted, the maximum number 316 of CPUs will be calculated from the provided topology members and the 317 initial CPU count will match the maximum number. When only one of them 318 is given then the omitted one will be set to its counterpart's value. 319 Both parameters may be specified, but the maximum number of CPUs must 320 be equal to or greater than the initial CPU count. Product of the 321 CPU topology hierarchy must be equal to the maximum number of CPUs. 322 Both parameters are subject to an upper limit that is determined by 323 the specific machine type chosen. 324 325 To control reporting of CPU topology information, values of the topology 326 parameters can be specified. Machines may only support a subset of the 327 parameters and different machines may have different subsets supported 328 which vary depending on capacity of the corresponding CPU targets. So 329 for a particular machine type board, an expected topology hierarchy can 330 be defined through the supported sub-option. Unsupported parameters can 331 also be provided in addition to the sub-option, but their values must be 332 set as 1 in the purpose of correct parsing. 333 334 Either the initial CPU count, or at least one of the topology parameters 335 must be specified. The specified parameters must be greater than zero, 336 explicit configuration like "cpus=0" is not allowed. Values for any 337 omitted parameters will be computed from those which are given. 338 339 For example, the following sub-option defines a CPU topology hierarchy 340 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 341 core) for a machine that only supports sockets/cores/threads. 342 Some members of the option can be omitted but their values will be 343 automatically computed: 344 345 :: 346 347 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 348 349 The following sub-option defines a CPU topology hierarchy (2 sockets 350 totally on the machine, 2 dies per socket, 2 modules per die, 2 cores per 351 module, 2 threads per core) for PC machines which support sockets/dies 352 /modules/cores/threads. Some members of the option can be omitted but 353 their values will be automatically computed: 354 355 :: 356 357 -smp 32,sockets=2,dies=2,modules=2,cores=2,threads=2,maxcpus=32 358 359 The following sub-option defines a CPU topology hierarchy (2 sockets 360 totally on the machine, 2 clusters per socket, 2 cores per cluster, 361 2 threads per core) for ARM virt machines which support sockets/clusters 362 /cores/threads. Some members of the option can be omitted but their values 363 will be automatically computed: 364 365 :: 366 367 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 368 369 Historically preference was given to the coarsest topology parameters 370 when computing missing values (ie sockets preferred over cores, which 371 were preferred over threads), however, this behaviour is considered 372 liable to change. Prior to 6.2 the preference was sockets over cores 373 over threads. Since 6.2 the preference is cores over sockets over threads. 374 375 For example, the following option defines a machine board with 2 sockets 376 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 377 378 :: 379 380 -smp 2 381 382 Note: The cluster topology will only be generated in ACPI and exposed 383 to guest if it's explicitly specified in -smp. 384ERST 385 386DEF("numa", HAS_ARG, QEMU_OPTION_numa, 387 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 388 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 389 "-numa dist,src=source,dst=destination,val=distance\n" 390 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 391 "-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" 392 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 393 QEMU_ARCH_ALL) 394SRST 395``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 396 \ 397``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 398 \ 399``-numa dist,src=source,dst=destination,val=distance`` 400 \ 401``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 402 \ 403``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 404 \ 405``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 406 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 407 distance from a source node to a destination node. Set the ACPI 408 Heterogeneous Memory Attributes for the given nodes. 409 410 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 411 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 412 contiguous range of CPU indexes (or a single VCPU if lastcpu is 413 omitted). A non-contiguous set of VCPUs can be represented by 414 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 415 omitted on all nodes, VCPUs are automatically split between them. 416 417 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 418 NUMA node: 419 420 :: 421 422 -numa node,cpus=0-2,cpus=5 423 424 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 425 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 426 assign CPU objects to a node using topology layout properties of 427 CPU. The set of properties is machine specific, and depends on used 428 machine type/'\ ``smp``\ ' options. It could be queried with 429 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 430 property specifies node to which CPU object will be assigned, it's 431 required for node to be declared with '\ ``node``\ ' option before 432 it's used with '\ ``cpu``\ ' option. 433 434 For example: 435 436 :: 437 438 -M pc \ 439 -smp 1,sockets=2,maxcpus=2 \ 440 -numa node,nodeid=0 -numa node,nodeid=1 \ 441 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 442 443 '\ ``memdev``\ ' option assigns RAM from a given memory backend 444 device to a node. It is recommended to use '\ ``memdev``\ ' option 445 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 446 option provides better performance and more control over the 447 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 448 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 449 450 For compatibility reasons, legacy '\ ``mem``\ ' option is 451 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 452 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 453 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 454 option, and vice versa. 455 456 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 457 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 458 for '\ ``-numa node``\ ' without memory specified was removed. 459 460 '\ ``initiator``\ ' is an additional option that points to an 461 initiator NUMA node that has best performance (the lowest latency or 462 largest bandwidth) to this NUMA node. Note that this option can be 463 set only when the machine property 'hmat' is set to 'on'. 464 465 Following example creates a machine with 2 NUMA nodes, node 0 has 466 CPU. node 1 has only memory, and its initiator is node 0. Note that 467 because node 0 has CPU, by default the initiator of node 0 is itself 468 and must be itself. 469 470 :: 471 472 -machine hmat=on \ 473 -m 2G,slots=2,maxmem=4G \ 474 -object memory-backend-ram,size=1G,id=m0 \ 475 -object memory-backend-ram,size=1G,id=m1 \ 476 -numa node,nodeid=0,memdev=m0 \ 477 -numa node,nodeid=1,memdev=m1,initiator=0 \ 478 -smp 2,sockets=2,maxcpus=2 \ 479 -numa cpu,node-id=0,socket-id=0 \ 480 -numa cpu,node-id=0,socket-id=1 481 482 source and destination are NUMA node IDs. distance is the NUMA 483 distance from source to destination. The distance from a node to 484 itself is always 10. If any pair of nodes is given a distance, then 485 all pairs must be given distances. Although, when distances are only 486 given in one direction for each pair of nodes, then the distances in 487 the opposite directions are assumed to be the same. If, however, an 488 asymmetrical pair of distances is given for even one node pair, then 489 all node pairs must be provided distance values for both directions, 490 even when they are symmetrical. When a node is unreachable from 491 another node, set the pair's distance to 255. 492 493 Note that the -``numa`` option doesn't allocate any of the specified 494 resources, it just assigns existing resources to NUMA nodes. This 495 means that one still has to use the ``-m``, ``-smp`` options to 496 allocate RAM and VCPUs respectively. 497 498 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 499 Information between initiator and target NUMA nodes in ACPI 500 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 501 create memory requests, usually it has one or more processors. 502 Target NUMA node contains addressable memory. 503 504 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 505 the memory hierarchy of the target NUMA node: if hierarchy is 506 'memory', the structure represents the memory performance; if 507 hierarchy is 'first-level\|second-level\|third-level', this 508 structure represents aggregated performance of memory side caches 509 for each domain. type of 'data-type' is type of data represented by 510 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 511 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 512 the target memory; if 'hierarchy' is 513 'first-level\|second-level\|third-level', 'data-type' is 514 'access\|read\|write' hit latency or 'access\|read\|write' hit 515 bandwidth of the target memory side cache. 516 517 lat is latency value in nanoseconds. bw is bandwidth value, the 518 possible value and units are NUM[M\|G\|T], mean that the bandwidth 519 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 520 used suffix). Note that if latency or bandwidth value is 0, means 521 the corresponding latency or bandwidth information is not provided. 522 523 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 524 belongs. size is the size of memory side cache in bytes. level is 525 the cache level described in this structure, note that the cache 526 level 0 should not be used with '\ ``hmat-cache``\ ' option. 527 associativity is the cache associativity, the possible value is 528 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 529 is the write policy. line is the cache Line size in bytes. 530 531 For example, the following options describe 2 NUMA nodes. Node 0 has 532 2 cpus and a ram, node 1 has only a ram. The processors in node 0 533 access memory in node 0 with access-latency 5 nanoseconds, 534 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 535 memory in NUMA node 1 with access-latency 10 nanoseconds, 536 access-bandwidth is 100 MB/s. And for memory side cache information, 537 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 538 policy is write-back, the cache Line size is 8 bytes: 539 540 :: 541 542 -machine hmat=on \ 543 -m 2G \ 544 -object memory-backend-ram,size=1G,id=m0 \ 545 -object memory-backend-ram,size=1G,id=m1 \ 546 -smp 2,sockets=2,maxcpus=2 \ 547 -numa node,nodeid=0,memdev=m0 \ 548 -numa node,nodeid=1,memdev=m1,initiator=0 \ 549 -numa cpu,node-id=0,socket-id=0 \ 550 -numa cpu,node-id=0,socket-id=1 \ 551 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 552 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 553 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 554 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 555 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 556 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 557ERST 558 559DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 560 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 561 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 562SRST 563``-add-fd fd=fd,set=set[,opaque=opaque]`` 564 Add a file descriptor to an fd set. Valid options are: 565 566 ``fd=fd`` 567 This option defines the file descriptor of which a duplicate is 568 added to fd set. The file descriptor cannot be stdin, stdout, or 569 stderr. 570 571 ``set=set`` 572 This option defines the ID of the fd set to add the file 573 descriptor to. 574 575 ``opaque=opaque`` 576 This option defines a free-form string that can be used to 577 describe fd. 578 579 You can open an image using pre-opened file descriptors from an fd 580 set: 581 582 .. parsed-literal:: 583 584 |qemu_system| \\ 585 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 586 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 587 -drive file=/dev/fdset/2,index=0,media=disk 588ERST 589 590DEF("set", HAS_ARG, QEMU_OPTION_set, 591 "-set group.id.arg=value\n" 592 " set <arg> parameter for item <id> of type <group>\n" 593 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 594SRST 595``-set group.id.arg=value`` 596 Set parameter arg for item id of type group 597ERST 598 599DEF("global", HAS_ARG, QEMU_OPTION_global, 600 "-global driver.property=value\n" 601 "-global driver=driver,property=property,value=value\n" 602 " set a global default for a driver property\n", 603 QEMU_ARCH_ALL) 604SRST 605``-global driver.prop=value`` 606 \ 607``-global driver=driver,property=property,value=value`` 608 Set default value of driver's property prop to value, e.g.: 609 610 .. parsed-literal:: 611 612 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 613 614 In particular, you can use this to set driver properties for devices 615 which are created automatically by the machine model. To create a 616 device which is not created automatically and set properties on it, 617 use -``device``. 618 619 -global driver.prop=value is shorthand for -global 620 driver=driver,property=prop,value=value. The longhand syntax works 621 even when driver contains a dot. 622ERST 623 624DEF("boot", HAS_ARG, QEMU_OPTION_boot, 625 "-boot [order=drives][,once=drives][,menu=on|off]\n" 626 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 627 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 628 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 629 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 630 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 631 QEMU_ARCH_ALL) 632SRST 633``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 634 Specify boot order drives as a string of drive letters. Valid drive 635 letters depend on the target architecture. The x86 PC uses: a, b 636 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 637 (Etherboot from network adapter 1-4), hard disk boot is the default. 638 To apply a particular boot order only on the first startup, specify 639 it via ``once``. Note that the ``order`` or ``once`` parameter 640 should not be used together with the ``bootindex`` property of 641 devices, since the firmware implementations normally do not support 642 both at the same time. 643 644 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 645 as firmware/BIOS supports them. The default is non-interactive boot. 646 647 A splash picture could be passed to bios, enabling user to show it 648 as logo, when option splash=sp\_name is given and menu=on, If 649 firmware/BIOS supports them. Currently Seabios for X86 system 650 support it. limitation: The splash file could be a jpeg file or a 651 BMP file in 24 BPP format(true color). The resolution should be 652 supported by the SVGA mode, so the recommended is 320x240, 640x480, 653 800x640. 654 655 A timeout could be passed to bios, guest will pause for rb\_timeout 656 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 657 not reboot, qemu passes '-1' to bios by default. Currently Seabios 658 for X86 system support it. 659 660 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 661 it. This only effects when boot priority is changed by bootindex 662 options. The default is non-strict boot. 663 664 .. parsed-literal:: 665 666 # try to boot from network first, then from hard disk 667 |qemu_system_x86| -boot order=nc 668 # boot from CD-ROM first, switch back to default order after reboot 669 |qemu_system_x86| -boot once=d 670 # boot with a splash picture for 5 seconds. 671 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 672 673 Note: The legacy format '-boot drives' is still supported but its 674 use is discouraged as it may be removed from future versions. 675ERST 676 677DEF("m", HAS_ARG, QEMU_OPTION_m, 678 "-m [size=]megs[,slots=n,maxmem=size]\n" 679 " configure guest RAM\n" 680 " size: initial amount of guest memory\n" 681 " slots: number of hotplug slots (default: none)\n" 682 " maxmem: maximum amount of guest memory (default: none)\n" 683 " Note: Some architectures might enforce a specific granularity\n", 684 QEMU_ARCH_ALL) 685SRST 686``-m [size=]megs[,slots=n,maxmem=size]`` 687 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 688 Optionally, a suffix of "M" or "G" can be used to signify a value in 689 megabytes or gigabytes respectively. Optional pair slots, maxmem 690 could be used to set amount of hotpluggable memory slots and maximum 691 amount of memory. Note that maxmem must be aligned to the page size. 692 693 For example, the following command-line sets the guest startup RAM 694 size to 1GB, creates 3 slots to hotplug additional memory and sets 695 the maximum memory the guest can reach to 4GB: 696 697 .. parsed-literal:: 698 699 |qemu_system| -m 1G,slots=3,maxmem=4G 700 701 If slots and maxmem are not specified, memory hotplug won't be 702 enabled and the guest startup RAM will never increase. 703ERST 704 705DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 706 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 707SRST 708``-mem-path path`` 709 Allocate guest RAM from a temporarily created file in path. 710ERST 711 712DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 713 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 714 QEMU_ARCH_ALL) 715SRST 716``-mem-prealloc`` 717 Preallocate memory when using -mem-path. 718ERST 719 720DEF("k", HAS_ARG, QEMU_OPTION_k, 721 "-k language use keyboard layout (for example 'fr' for French)\n", 722 QEMU_ARCH_ALL) 723SRST 724``-k language`` 725 Use keyboard layout language (for example ``fr`` for French). This 726 option is only needed where it is not easy to get raw PC keycodes 727 (e.g. on Macs, with some X11 servers or with a VNC or curses 728 display). You don't normally need to use it on PC/Linux or 729 PC/Windows hosts. 730 731 The available layouts are: 732 733 :: 734 735 ar de-ch es fo fr-ca hu ja mk no pt-br sv 736 da en-gb et fr fr-ch is lt nl pl ru th 737 de en-us fi fr-be hr it lv nl-be pt sl tr 738 739 The default is ``en-us``. 740ERST 741 742 743DEF("audio", HAS_ARG, QEMU_OPTION_audio, 744 "-audio [driver=]driver[,prop[=value][,...]]\n" 745 " specifies default audio backend when `audiodev` is not\n" 746 " used to create a machine or sound device;" 747 " options are the same as for -audiodev\n" 748 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 749 " specifies the audio backend and device to use;\n" 750 " apart from 'model', options are the same as for -audiodev.\n" 751 " use '-audio model=help' to show possible devices.\n", 752 QEMU_ARCH_ALL) 753SRST 754``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 755 If the ``model`` option is specified, ``-audio`` is a shortcut 756 for configuring both the guest audio hardware and the host audio 757 backend in one go. The guest hardware model can be set with 758 ``model=modelname``. Use ``model=help`` to list the available 759 device types. 760 761 The following two example do exactly the same, to show how ``-audio`` 762 can be used to shorten the command line length: 763 764 .. parsed-literal:: 765 766 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 767 |qemu_system| -audio pa,model=sb16 768 769 If the ``model`` option is not specified, ``-audio`` is used to 770 configure a default audio backend that will be used whenever the 771 ``audiodev`` property is not set on a device or machine. In 772 particular, ``-audio none`` ensures that no audio is produced even 773 for machines that have embedded sound hardware. 774 775 In both cases, the driver option is the same as with the corresponding 776 ``-audiodev`` option below. Use ``driver=help`` to list the available 777 drivers. 778 779ERST 780 781DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 782 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 783 " specifies the audio backend to use\n" 784 " Use ``-audiodev help`` to list the available drivers\n" 785 " id= identifier of the backend\n" 786 " timer-period= timer period in microseconds\n" 787 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 788 " in|out.fixed-settings= use fixed settings for host audio\n" 789 " in|out.frequency= frequency to use with fixed settings\n" 790 " in|out.channels= number of channels to use with fixed settings\n" 791 " in|out.format= sample format to use with fixed settings\n" 792 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 793 " in|out.voices= number of voices to use\n" 794 " in|out.buffer-length= length of buffer in microseconds\n" 795 "-audiodev none,id=id,[,prop[=value][,...]]\n" 796 " dummy driver that discards all output\n" 797#ifdef CONFIG_AUDIO_ALSA 798 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 799 " in|out.dev= name of the audio device to use\n" 800 " in|out.period-length= length of period in microseconds\n" 801 " in|out.try-poll= attempt to use poll mode\n" 802 " threshold= threshold (in microseconds) when playback starts\n" 803#endif 804#ifdef CONFIG_AUDIO_COREAUDIO 805 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 806 " in|out.buffer-count= number of buffers\n" 807#endif 808#ifdef CONFIG_AUDIO_DSOUND 809 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 810 " latency= add extra latency to playback in microseconds\n" 811#endif 812#ifdef CONFIG_AUDIO_OSS 813 "-audiodev oss,id=id[,prop[=value][,...]]\n" 814 " in|out.dev= path of the audio device to use\n" 815 " in|out.buffer-count= number of buffers\n" 816 " in|out.try-poll= attempt to use poll mode\n" 817 " try-mmap= try using memory mapped access\n" 818 " exclusive= open device in exclusive mode\n" 819 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 820#endif 821#ifdef CONFIG_AUDIO_PA 822 "-audiodev pa,id=id[,prop[=value][,...]]\n" 823 " server= PulseAudio server address\n" 824 " in|out.name= source/sink device name\n" 825 " in|out.latency= desired latency in microseconds\n" 826#endif 827#ifdef CONFIG_AUDIO_PIPEWIRE 828 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 829 " in|out.name= source/sink device name\n" 830 " in|out.stream-name= name of pipewire stream\n" 831 " in|out.latency= desired latency in microseconds\n" 832#endif 833#ifdef CONFIG_AUDIO_SDL 834 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 835 " in|out.buffer-count= number of buffers\n" 836#endif 837#ifdef CONFIG_AUDIO_SNDIO 838 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 839#endif 840#ifdef CONFIG_SPICE 841 "-audiodev spice,id=id[,prop[=value][,...]]\n" 842#endif 843#ifdef CONFIG_DBUS_DISPLAY 844 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 845#endif 846 "-audiodev wav,id=id[,prop[=value][,...]]\n" 847 " path= path of wav file to record\n", 848 QEMU_ARCH_ALL) 849SRST 850``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 851 Adds a new audio backend driver identified by id. There are global 852 and driver specific properties. Some values can be set differently 853 for input and output, they're marked with ``in|out.``. You can set 854 the input's property with ``in.prop`` and the output's property with 855 ``out.prop``. For example: 856 857 :: 858 859 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 860 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 861 862 NOTE: parameter validation is known to be incomplete, in many cases 863 specifying an invalid option causes QEMU to print an error message 864 and continue emulation without sound. 865 866 Valid global options are: 867 868 ``id=identifier`` 869 Identifies the audio backend. 870 871 ``timer-period=period`` 872 Sets the timer period used by the audio subsystem in 873 microseconds. Default is 10000 (10 ms). 874 875 ``in|out.mixing-engine=on|off`` 876 Use QEMU's mixing engine to mix all streams inside QEMU and 877 convert audio formats when not supported by the backend. When 878 off, fixed-settings must be off too. Note that disabling this 879 option means that the selected backend must support multiple 880 streams and the audio formats used by the virtual cards, 881 otherwise you'll get no sound. It's not recommended to disable 882 this option unless you want to use 5.1 or 7.1 audio, as mixing 883 engine only supports mono and stereo audio. Default is on. 884 885 ``in|out.fixed-settings=on|off`` 886 Use fixed settings for host audio. When off, it will change 887 based on how the guest opens the sound card. In this case you 888 must not specify frequency, channels or format. Default is on. 889 890 ``in|out.frequency=frequency`` 891 Specify the frequency to use when using fixed-settings. Default 892 is 44100Hz. 893 894 ``in|out.channels=channels`` 895 Specify the number of channels to use when using fixed-settings. 896 Default is 2 (stereo). 897 898 ``in|out.format=format`` 899 Specify the sample format to use when using fixed-settings. 900 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 901 ``u32``, ``f32``. Default is ``s16``. 902 903 ``in|out.voices=voices`` 904 Specify the number of voices to use. Default is 1. 905 906 ``in|out.buffer-length=usecs`` 907 Sets the size of the buffer in microseconds. 908 909``-audiodev none,id=id[,prop[=value][,...]]`` 910 Creates a dummy backend that discards all outputs. This backend has 911 no backend specific properties. 912 913``-audiodev alsa,id=id[,prop[=value][,...]]`` 914 Creates backend using the ALSA. This backend is only available on 915 Linux. 916 917 ALSA specific options are: 918 919 ``in|out.dev=device`` 920 Specify the ALSA device to use for input and/or output. Default 921 is ``default``. 922 923 ``in|out.period-length=usecs`` 924 Sets the period length in microseconds. 925 926 ``in|out.try-poll=on|off`` 927 Attempt to use poll mode with the device. Default is on. 928 929 ``threshold=threshold`` 930 Threshold (in microseconds) when playback starts. Default is 0. 931 932``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 933 Creates a backend using Apple's Core Audio. This backend is only 934 available on Mac OS and only supports playback. 935 936 Core Audio specific options are: 937 938 ``in|out.buffer-count=count`` 939 Sets the count of the buffers. 940 941``-audiodev dsound,id=id[,prop[=value][,...]]`` 942 Creates a backend using Microsoft's DirectSound. This backend is 943 only available on Windows and only supports playback. 944 945 DirectSound specific options are: 946 947 ``latency=usecs`` 948 Add extra usecs microseconds latency to playback. Default is 949 10000 (10 ms). 950 951``-audiodev oss,id=id[,prop[=value][,...]]`` 952 Creates a backend using OSS. This backend is available on most 953 Unix-like systems. 954 955 OSS specific options are: 956 957 ``in|out.dev=device`` 958 Specify the file name of the OSS device to use. Default is 959 ``/dev/dsp``. 960 961 ``in|out.buffer-count=count`` 962 Sets the count of the buffers. 963 964 ``in|out.try-poll=on|of`` 965 Attempt to use poll mode with the device. Default is on. 966 967 ``try-mmap=on|off`` 968 Try using memory mapped device access. Default is off. 969 970 ``exclusive=on|off`` 971 Open the device in exclusive mode (vmix won't work in this 972 case). Default is off. 973 974 ``dsp-policy=policy`` 975 Sets the timing policy (between 0 and 10, where smaller number 976 means smaller latency but higher CPU usage). Use -1 to use 977 buffer sizes specified by ``buffer`` and ``buffer-count``. This 978 option is ignored if you do not have OSS 4. Default is 5. 979 980``-audiodev pa,id=id[,prop[=value][,...]]`` 981 Creates a backend using PulseAudio. This backend is available on 982 most systems. 983 984 PulseAudio specific options are: 985 986 ``server=server`` 987 Sets the PulseAudio server to connect to. 988 989 ``in|out.name=sink`` 990 Use the specified source/sink for recording/playback. 991 992 ``in|out.latency=usecs`` 993 Desired latency in microseconds. The PulseAudio server will try 994 to honor this value but actual latencies may be lower or higher. 995 996``-audiodev pipewire,id=id[,prop[=value][,...]]`` 997 Creates a backend using PipeWire. This backend is available on 998 most systems. 999 1000 PipeWire specific options are: 1001 1002 ``in|out.latency=usecs`` 1003 Desired latency in microseconds. 1004 1005 ``in|out.name=sink`` 1006 Use the specified source/sink for recording/playback. 1007 1008 ``in|out.stream-name`` 1009 Specify the name of pipewire stream. 1010 1011``-audiodev sdl,id=id[,prop[=value][,...]]`` 1012 Creates a backend using SDL. This backend is available on most 1013 systems, but you should use your platform's native backend if 1014 possible. 1015 1016 SDL specific options are: 1017 1018 ``in|out.buffer-count=count`` 1019 Sets the count of the buffers. 1020 1021``-audiodev sndio,id=id[,prop[=value][,...]]`` 1022 Creates a backend using SNDIO. This backend is available on 1023 OpenBSD and most other Unix-like systems. 1024 1025 Sndio specific options are: 1026 1027 ``in|out.dev=device`` 1028 Specify the sndio device to use for input and/or output. Default 1029 is ``default``. 1030 1031 ``in|out.latency=usecs`` 1032 Sets the desired period length in microseconds. 1033 1034``-audiodev spice,id=id[,prop[=value][,...]]`` 1035 Creates a backend that sends audio through SPICE. This backend 1036 requires ``-spice`` and automatically selected in that case, so 1037 usually you can ignore this option. This backend has no backend 1038 specific properties. 1039 1040``-audiodev wav,id=id[,prop[=value][,...]]`` 1041 Creates a backend that writes audio to a WAV file. 1042 1043 Backend specific options are: 1044 1045 ``path=path`` 1046 Write recorded audio into the specified file. Default is 1047 ``qemu.wav``. 1048ERST 1049 1050DEF("device", HAS_ARG, QEMU_OPTION_device, 1051 "-device driver[,prop[=value][,...]]\n" 1052 " add device (based on driver)\n" 1053 " prop=value,... sets driver properties\n" 1054 " use '-device help' to print all possible drivers\n" 1055 " use '-device driver,help' to print all possible properties\n", 1056 QEMU_ARCH_ALL) 1057SRST 1058``-device driver[,prop[=value][,...]]`` 1059 Add device driver. prop=value sets driver properties. Valid 1060 properties depend on the driver. To get help on possible drivers and 1061 properties, use ``-device help`` and ``-device driver,help``. 1062 1063 Some drivers are: 1064 1065``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1066 Add an IPMI BMC. This is a simulation of a hardware management 1067 interface processor that normally sits on a system. It provides a 1068 watchdog and the ability to reset and power control the system. You 1069 need to connect this to an IPMI interface to make it useful 1070 1071 The IPMI slave address to use for the BMC. The default is 0x20. This 1072 address is the BMC's address on the I2C network of management 1073 controllers. If you don't know what this means, it is safe to ignore 1074 it. 1075 1076 ``id=id`` 1077 The BMC id for interfaces to use this device. 1078 1079 ``slave_addr=val`` 1080 Define slave address to use for the BMC. The default is 0x20. 1081 1082 ``sdrfile=file`` 1083 file containing raw Sensor Data Records (SDR) data. The default 1084 is none. 1085 1086 ``fruareasize=val`` 1087 size of a Field Replaceable Unit (FRU) area. The default is 1088 1024. 1089 1090 ``frudatafile=file`` 1091 file containing raw Field Replaceable Unit (FRU) inventory data. 1092 The default is none. 1093 1094 ``guid=uuid`` 1095 value for the GUID for the BMC, in standard UUID format. If this 1096 is set, get "Get GUID" command to the BMC will return it. 1097 Otherwise "Get GUID" will return an error. 1098 1099``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1100 Add a connection to an external IPMI BMC simulator. Instead of 1101 locally emulating the BMC like the above item, instead connect to an 1102 external entity that provides the IPMI services. 1103 1104 A connection is made to an external BMC simulator. If you do this, 1105 it is strongly recommended that you use the "reconnect=" chardev 1106 option to reconnect to the simulator if the connection is lost. Note 1107 that if this is not used carefully, it can be a security issue, as 1108 the interface has the ability to send resets, NMIs, and power off 1109 the VM. It's best if QEMU makes a connection to an external 1110 simulator running on a secure port on localhost, so neither the 1111 simulator nor QEMU is exposed to any outside network. 1112 1113 See the "lanserv/README.vm" file in the OpenIPMI library for more 1114 details on the external interface. 1115 1116``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1117 Add a KCS IPMI interface on the ISA bus. This also adds a 1118 corresponding ACPI and SMBIOS entries, if appropriate. 1119 1120 ``bmc=id`` 1121 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1122 above. 1123 1124 ``ioport=val`` 1125 Define the I/O address of the interface. The default is 0xca0 1126 for KCS. 1127 1128 ``irq=val`` 1129 Define the interrupt to use. The default is 5. To disable 1130 interrupts, set this to 0. 1131 1132``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1133 Like the KCS interface, but defines a BT interface. The default port 1134 is 0xe4 and the default interrupt is 5. 1135 1136``-device pci-ipmi-kcs,bmc=id`` 1137 Add a KCS IPMI interface on the PCI bus. 1138 1139 ``bmc=id`` 1140 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1141 1142``-device pci-ipmi-bt,bmc=id`` 1143 Like the KCS interface, but defines a BT interface on the PCI bus. 1144 1145``-device intel-iommu[,option=...]`` 1146 This is only supported by ``-machine q35``, which will enable Intel VT-d 1147 emulation within the guest. It supports below options: 1148 1149 ``intremap=on|off`` (default: auto) 1150 This enables interrupt remapping feature. It's required to enable 1151 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1152 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1153 The default value is "auto", which will be decided by the mode of 1154 kernel-irqchip. 1155 1156 ``caching-mode=on|off`` (default: off) 1157 This enables caching mode for the VT-d emulated device. When 1158 caching-mode is enabled, each guest DMA buffer mapping will generate an 1159 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1160 a synchronous way. It is required for ``-device vfio-pci`` to work 1161 with the VT-d device, because host assigned devices requires to setup 1162 the DMA mapping on the host before guest DMA starts. 1163 1164 ``device-iotlb=on|off`` (default: off) 1165 This enables device-iotlb capability for the emulated VT-d device. So 1166 far virtio/vhost should be the only real user for this parameter, 1167 paired with ats=on configured for the device. 1168 1169 ``aw-bits=39|48`` (default: 39) 1170 This decides the address width of IOVA address space. The address 1171 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1172 4-level IOMMU page tables. 1173 1174 Please also refer to the wiki page for general scenarios of VT-d 1175 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1176 1177``-device virtio-iommu-pci[,option=...]`` 1178 This is only supported by ``-machine q35`` (x86_64) and ``-machine virt`` (ARM). 1179 It supports below options: 1180 1181 ``granule=val`` (possible values are 4k, 8k, 16k, 64k and host; default: host) 1182 This decides the default granule to be be exposed by the 1183 virtio-iommu. If host, the granule matches the host page size. 1184 1185 ``aw-bits=val`` (val between 32 and 64, default depends on machine) 1186 This decides the address width of the IOVA address space. 1187 1188ERST 1189 1190DEF("name", HAS_ARG, QEMU_OPTION_name, 1191 "-name string1[,process=string2][,debug-threads=on|off]\n" 1192 " set the name of the guest\n" 1193 " string1 sets the window title and string2 the process name\n" 1194 " When debug-threads is enabled, individual threads are given a separate name\n" 1195 " NOTE: The thread names are for debugging and not a stable API.\n", 1196 QEMU_ARCH_ALL) 1197SRST 1198``-name name`` 1199 Sets the name of the guest. This name will be displayed in the SDL 1200 window caption. The name will also be used for the VNC server. Also 1201 optionally set the top visible process name in Linux. Naming of 1202 individual threads can also be enabled on Linux to aid debugging. 1203ERST 1204 1205DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1206 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1207 " specify machine UUID\n", QEMU_ARCH_ALL) 1208SRST 1209``-uuid uuid`` 1210 Set system UUID. 1211ERST 1212 1213DEFHEADING() 1214 1215DEFHEADING(Block device options:) 1216 1217SRST 1218The QEMU block device handling options have a long history and 1219have gone through several iterations as the feature set and complexity 1220of the block layer have grown. Many online guides to QEMU often 1221reference older and deprecated options, which can lead to confusion. 1222 1223The most explicit way to describe disks is to use a combination of 1224``-device`` to specify the hardware device and ``-blockdev`` to 1225describe the backend. The device defines what the guest sees and the 1226backend describes how QEMU handles the data. It is the only guaranteed 1227stable interface for describing block devices and as such is 1228recommended for management tools and scripting. 1229 1230The ``-drive`` option combines the device and backend into a single 1231command line option which is a more human friendly. There is however no 1232interface stability guarantee although some older board models still 1233need updating to work with the modern blockdev forms. 1234 1235Older options like ``-hda`` are essentially macros which expand into 1236``-drive`` options for various drive interfaces. The original forms 1237bake in a lot of assumptions from the days when QEMU was emulating a 1238legacy PC, they are not recommended for modern configurations. 1239 1240ERST 1241 1242DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1243 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1244DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1245SRST 1246``-fda file`` 1247 \ 1248``-fdb file`` 1249 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1250 the System Emulation Users Guide). 1251ERST 1252 1253DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1254 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1255DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1256DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1257 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1258DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1259SRST 1260``-hda file`` 1261 \ 1262``-hdb file`` 1263 \ 1264``-hdc file`` 1265 \ 1266``-hdd file`` 1267 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1268 emulated machine (this is for example the IDE bus on most x86 machines, 1269 but it can also be SCSI, virtio or something else on other target 1270 architectures). See also the :ref:`disk images` chapter in the System 1271 Emulation Users Guide. 1272ERST 1273 1274DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1275 "-cdrom file use 'file' as CD-ROM image\n", 1276 QEMU_ARCH_ALL) 1277SRST 1278``-cdrom file`` 1279 Use file as CD-ROM image on the default bus of the emulated machine 1280 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1281 at the same time there). On systems that support it, you can use the 1282 host CD-ROM by using ``/dev/cdrom`` as filename. 1283ERST 1284 1285DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1286 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1287 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1288 " [,read-only=on|off][,auto-read-only=on|off]\n" 1289 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1290 " [,driver specific parameters...]\n" 1291 " configure a block backend\n", QEMU_ARCH_ALL) 1292SRST 1293``-blockdev option[,option[,option[,...]]]`` 1294 Define a new block driver node. Some of the options apply to all 1295 block drivers, other options are only accepted for a specific block 1296 driver. See below for a list of generic options and options for the 1297 most common block drivers. 1298 1299 Options that expect a reference to another node (e.g. ``file``) can 1300 be given in two ways. Either you specify the node name of an already 1301 existing node (file=node-name), or you define a new node inline, 1302 adding options for the referenced node after a dot 1303 (file.filename=path,file.aio=native). 1304 1305 A block driver node created with ``-blockdev`` can be used for a 1306 guest device by specifying its node name for the ``drive`` property 1307 in a ``-device`` argument that defines a block device. 1308 1309 ``Valid options for any block driver node:`` 1310 ``driver`` 1311 Specifies the block driver to use for the given node. 1312 1313 ``node-name`` 1314 This defines the name of the block driver node by which it 1315 will be referenced later. The name must be unique, i.e. it 1316 must not match the name of a different block driver node, or 1317 (if you use ``-drive`` as well) the ID of a drive. 1318 1319 If no node name is specified, it is automatically generated. 1320 The generated node name is not intended to be predictable 1321 and changes between QEMU invocations. For the top level, an 1322 explicit node name must be specified. 1323 1324 ``read-only`` 1325 Open the node read-only. Guest write attempts will fail. 1326 1327 Note that some block drivers support only read-only access, 1328 either generally or in certain configurations. In this case, 1329 the default value ``read-only=off`` does not work and the 1330 option must be specified explicitly. 1331 1332 ``auto-read-only`` 1333 If ``auto-read-only=on`` is set, QEMU may fall back to 1334 read-only usage even when ``read-only=off`` is requested, or 1335 even switch between modes as needed, e.g. depending on 1336 whether the image file is writable or whether a writing user 1337 is attached to the node. 1338 1339 ``force-share`` 1340 Override the image locking system of QEMU by forcing the 1341 node to utilize weaker shared access for permissions where 1342 it would normally request exclusive access. When there is 1343 the potential for multiple instances to have the same file 1344 open (whether this invocation of QEMU is the first or the 1345 second instance), both instances must permit shared access 1346 for the second instance to succeed at opening the file. 1347 1348 Enabling ``force-share=on`` requires ``read-only=on``. 1349 1350 ``cache.direct`` 1351 The host page cache can be avoided with ``cache.direct=on``. 1352 This will attempt to do disk IO directly to the guest's 1353 memory. QEMU may still perform an internal copy of the data. 1354 1355 ``cache.no-flush`` 1356 In case you don't care about data integrity over host 1357 failures, you can use ``cache.no-flush=on``. This option 1358 tells QEMU that it never needs to write any data to the disk 1359 but can instead keep things in cache. If anything goes 1360 wrong, like your host losing power, the disk storage getting 1361 disconnected accidentally, etc. your image will most 1362 probably be rendered unusable. 1363 1364 ``discard=discard`` 1365 discard is one of "ignore" (or "off") or "unmap" (or "on") 1366 and controls whether ``discard`` (also known as ``trim`` or 1367 ``unmap``) requests are ignored or passed to the filesystem. 1368 Some machine types may not support discard requests. 1369 1370 ``detect-zeroes=detect-zeroes`` 1371 detect-zeroes is "off", "on" or "unmap" and enables the 1372 automatic conversion of plain zero writes by the OS to 1373 driver specific optimized zero write commands. You may even 1374 choose "unmap" if discard is set to "unmap" to allow a zero 1375 write to be converted to an ``unmap`` operation. 1376 1377 ``Driver-specific options for file`` 1378 This is the protocol-level block driver for accessing regular 1379 files. 1380 1381 ``filename`` 1382 The path to the image file in the local filesystem 1383 1384 ``aio`` 1385 Specifies the AIO backend (threads/native/io_uring, 1386 default: threads) 1387 1388 ``locking`` 1389 Specifies whether the image file is protected with Linux OFD 1390 / POSIX locks. The default is to use the Linux Open File 1391 Descriptor API if available, otherwise no lock is applied. 1392 (auto/on/off, default: auto) 1393 1394 Example: 1395 1396 :: 1397 1398 -blockdev driver=file,node-name=disk,filename=disk.img 1399 1400 ``Driver-specific options for raw`` 1401 This is the image format block driver for raw images. It is 1402 usually stacked on top of a protocol level block driver such as 1403 ``file``. 1404 1405 ``file`` 1406 Reference to or definition of the data source block driver 1407 node (e.g. a ``file`` driver node) 1408 1409 Example 1: 1410 1411 :: 1412 1413 -blockdev driver=file,node-name=disk_file,filename=disk.img 1414 -blockdev driver=raw,node-name=disk,file=disk_file 1415 1416 Example 2: 1417 1418 :: 1419 1420 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1421 1422 ``Driver-specific options for qcow2`` 1423 This is the image format block driver for qcow2 images. It is 1424 usually stacked on top of a protocol level block driver such as 1425 ``file``. 1426 1427 ``file`` 1428 Reference to or definition of the data source block driver 1429 node (e.g. a ``file`` driver node) 1430 1431 ``backing`` 1432 Reference to or definition of the backing file block device 1433 (default is taken from the image file). It is allowed to 1434 pass ``null`` here in order to disable the default backing 1435 file. 1436 1437 ``lazy-refcounts`` 1438 Whether to enable the lazy refcounts feature (on/off; 1439 default is taken from the image file) 1440 1441 ``cache-size`` 1442 The maximum total size of the L2 table and refcount block 1443 caches in bytes (default: the sum of l2-cache-size and 1444 refcount-cache-size) 1445 1446 ``l2-cache-size`` 1447 The maximum size of the L2 table cache in bytes (default: if 1448 cache-size is not specified - 32M on Linux platforms, and 8M 1449 on non-Linux platforms; otherwise, as large as possible 1450 within the cache-size, while permitting the requested or the 1451 minimal refcount cache size) 1452 1453 ``refcount-cache-size`` 1454 The maximum size of the refcount block cache in bytes 1455 (default: 4 times the cluster size; or if cache-size is 1456 specified, the part of it which is not used for the L2 1457 cache) 1458 1459 ``cache-clean-interval`` 1460 Clean unused entries in the L2 and refcount caches. The 1461 interval is in seconds. The default value is 600 on 1462 supporting platforms, and 0 on other platforms. Setting it 1463 to 0 disables this feature. 1464 1465 ``pass-discard-request`` 1466 Whether discard requests to the qcow2 device should be 1467 forwarded to the data source (on/off; default: on if 1468 discard=unmap is specified, off otherwise) 1469 1470 ``pass-discard-snapshot`` 1471 Whether discard requests for the data source should be 1472 issued when a snapshot operation (e.g. deleting a snapshot) 1473 frees clusters in the qcow2 file (on/off; default: on) 1474 1475 ``pass-discard-other`` 1476 Whether discard requests for the data source should be 1477 issued on other occasions where a cluster gets freed 1478 (on/off; default: off) 1479 1480 ``discard-no-unref`` 1481 When enabled, data clusters will remain preallocated when they are 1482 no longer used, e.g. because they are discarded or converted to 1483 zero clusters. As usual, whether the old data is discarded or kept 1484 on the protocol level (i.e. in the image file) depends on the 1485 setting of the pass-discard-request option. Keeping the clusters 1486 preallocated prevents qcow2 fragmentation that would otherwise be 1487 caused by freeing and re-allocating them later. Besides potential 1488 performance degradation, such fragmentation can lead to increased 1489 allocation of clusters past the end of the image file, 1490 resulting in image files whose file length can grow much larger 1491 than their guest disk size would suggest. 1492 If image file length is of concern (e.g. when storing qcow2 1493 images directly on block devices), you should consider enabling 1494 this option. 1495 1496 ``overlap-check`` 1497 Which overlap checks to perform for writes to the image 1498 (none/constant/cached/all; default: cached). For details or 1499 finer granularity control refer to the QAPI documentation of 1500 ``blockdev-add``. 1501 1502 Example 1: 1503 1504 :: 1505 1506 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1507 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1508 1509 Example 2: 1510 1511 :: 1512 1513 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1514 1515 ``Driver-specific options for other drivers`` 1516 Please refer to the QAPI documentation of the ``blockdev-add`` 1517 QMP command. 1518ERST 1519 1520DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1521 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1522 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1523 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1524 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1525 " [,aio=threads|native|io_uring]\n" 1526 " [,readonly=on|off][,copy-on-read=on|off]\n" 1527 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1528 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1529 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1530 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1531 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1532 " [[,iops_size=is]]\n" 1533 " [[,group=g]]\n" 1534 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1535SRST 1536``-drive option[,option[,option[,...]]]`` 1537 Define a new drive. This includes creating a block driver node (the 1538 backend) as well as a guest device, and is mostly a shortcut for 1539 defining the corresponding ``-blockdev`` and ``-device`` options. 1540 1541 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1542 In addition, it knows the following options: 1543 1544 ``file=file`` 1545 This option defines which disk image (see the :ref:`disk images` 1546 chapter in the System Emulation Users Guide) to use with this drive. 1547 If the filename contains comma, you must double it (for instance, 1548 "file=my,,file" to use file "my,file"). 1549 1550 Special files such as iSCSI devices can be specified using 1551 protocol specific URLs. See the section for "Device URL Syntax" 1552 for more information. 1553 1554 ``if=interface`` 1555 This option defines on which type on interface the drive is 1556 connected. Available types are: ide, scsi, sd, mtd, floppy, 1557 pflash, virtio, none. 1558 1559 ``bus=bus,unit=unit`` 1560 These options define where is connected the drive by defining 1561 the bus number and the unit id. 1562 1563 ``index=index`` 1564 This option defines where the drive is connected by using an 1565 index in the list of available connectors of a given interface 1566 type. 1567 1568 ``media=media`` 1569 This option defines the type of the media: disk or cdrom. 1570 1571 ``snapshot=snapshot`` 1572 snapshot is "on" or "off" and controls snapshot mode for the 1573 given drive (see ``-snapshot``). 1574 1575 ``cache=cache`` 1576 cache is "none", "writeback", "unsafe", "directsync" or 1577 "writethrough" and controls how the host cache is used to access 1578 block data. This is a shortcut that sets the ``cache.direct`` 1579 and ``cache.no-flush`` options (as in ``-blockdev``), and 1580 additionally ``cache.writeback``, which provides a default for 1581 the ``write-cache`` option of block guest devices (as in 1582 ``-device``). The modes correspond to the following settings: 1583 1584 ============= =============== ============ ============== 1585 \ cache.writeback cache.direct cache.no-flush 1586 ============= =============== ============ ============== 1587 writeback on off off 1588 none on on off 1589 writethrough off off off 1590 directsync off on off 1591 unsafe on off on 1592 ============= =============== ============ ============== 1593 1594 The default mode is ``cache=writeback``. 1595 1596 ``aio=aio`` 1597 aio is "threads", "native", or "io_uring" and selects between pthread 1598 based disk I/O, native Linux AIO, or Linux io_uring API. 1599 1600 ``format=format`` 1601 Specify which disk format will be used rather than detecting the 1602 format. Can be used to specify format=raw to avoid interpreting 1603 an untrusted format header. 1604 1605 ``werror=action,rerror=action`` 1606 Specify which action to take on write and read errors. Valid 1607 actions are: "ignore" (ignore the error and try to continue), 1608 "stop" (pause QEMU), "report" (report the error to the guest), 1609 "enospc" (pause QEMU only if the host disk is full; report the 1610 error to the guest otherwise). The default setting is 1611 ``werror=enospc`` and ``rerror=report``. 1612 1613 ``copy-on-read=copy-on-read`` 1614 copy-on-read is "on" or "off" and enables whether to copy read 1615 backing file sectors into the image file. 1616 1617 ``bps=b,bps_rd=r,bps_wr=w`` 1618 Specify bandwidth throttling limits in bytes per second, either 1619 for all request types or for reads or writes only. Small values 1620 can lead to timeouts or hangs inside the guest. A safe minimum 1621 for disks is 2 MB/s. 1622 1623 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1624 Specify bursts in bytes per second, either for all request types 1625 or for reads or writes only. Bursts allow the guest I/O to spike 1626 above the limit temporarily. 1627 1628 ``iops=i,iops_rd=r,iops_wr=w`` 1629 Specify request rate limits in requests per second, either for 1630 all request types or for reads or writes only. 1631 1632 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1633 Specify bursts in requests per second, either for all request 1634 types or for reads or writes only. Bursts allow the guest I/O to 1635 spike above the limit temporarily. 1636 1637 ``iops_size=is`` 1638 Let every is bytes of a request count as a new request for iops 1639 throttling purposes. Use this option to prevent guests from 1640 circumventing iops limits by sending fewer but larger requests. 1641 1642 ``group=g`` 1643 Join a throttling quota group with given name g. All drives that 1644 are members of the same group are accounted for together. Use 1645 this option to prevent guests from circumventing throttling 1646 limits by using many small disks instead of a single larger 1647 disk. 1648 1649 By default, the ``cache.writeback=on`` mode is used. It will report 1650 data writes as completed as soon as the data is present in the host 1651 page cache. This is safe as long as your guest OS makes sure to 1652 correctly flush disk caches where needed. If your guest OS does not 1653 handle volatile disk write caches correctly and your host crashes or 1654 loses power, then the guest may experience data corruption. 1655 1656 For such guests, you should consider using ``cache.writeback=off``. 1657 This means that the host page cache will be used to read and write 1658 data, but write notification will be sent to the guest only after 1659 QEMU has made sure to flush each write to the disk. Be aware that 1660 this has a major impact on performance. 1661 1662 When using the ``-snapshot`` option, unsafe caching is always used. 1663 1664 Copy-on-read avoids accessing the same backing file sectors 1665 repeatedly and is useful when the backing file is over a slow 1666 network. By default copy-on-read is off. 1667 1668 Instead of ``-cdrom`` you can use: 1669 1670 .. parsed-literal:: 1671 1672 |qemu_system| -drive file=file,index=2,media=cdrom 1673 1674 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1675 1676 .. parsed-literal:: 1677 1678 |qemu_system| -drive file=file,index=0,media=disk 1679 |qemu_system| -drive file=file,index=1,media=disk 1680 |qemu_system| -drive file=file,index=2,media=disk 1681 |qemu_system| -drive file=file,index=3,media=disk 1682 1683 You can open an image using pre-opened file descriptors from an fd 1684 set: 1685 1686 .. parsed-literal:: 1687 1688 |qemu_system| \\ 1689 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1690 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1691 -drive file=/dev/fdset/2,index=0,media=disk 1692 1693 You can connect a CDROM to the slave of ide0: 1694 1695 .. parsed-literal:: 1696 1697 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1698 1699 If you don't specify the "file=" argument, you define an empty 1700 drive: 1701 1702 .. parsed-literal:: 1703 1704 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1705 1706 Instead of ``-fda``, ``-fdb``, you can use: 1707 1708 .. parsed-literal:: 1709 1710 |qemu_system_x86| -drive file=file,index=0,if=floppy 1711 |qemu_system_x86| -drive file=file,index=1,if=floppy 1712 1713 By default, interface is "ide" and index is automatically 1714 incremented: 1715 1716 .. parsed-literal:: 1717 1718 |qemu_system_x86| -drive file=a -drive file=b 1719 1720 is interpreted like: 1721 1722 .. parsed-literal:: 1723 1724 |qemu_system_x86| -hda a -hdb b 1725ERST 1726 1727DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1728 "-mtdblock file use 'file' as on-board Flash memory image\n", 1729 QEMU_ARCH_ALL) 1730SRST 1731``-mtdblock file`` 1732 Use file as on-board Flash memory image. 1733ERST 1734 1735DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1736 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1737SRST 1738``-sd file`` 1739 Use file as SecureDigital card image. 1740ERST 1741 1742DEF("snapshot", 0, QEMU_OPTION_snapshot, 1743 "-snapshot write to temporary files instead of disk image files\n", 1744 QEMU_ARCH_ALL) 1745SRST 1746``-snapshot`` 1747 Write to temporary files instead of disk image files. In this case, 1748 the raw disk image you use is not written back. You can however 1749 force the write back by pressing C-a s (see the :ref:`disk images` 1750 chapter in the System Emulation Users Guide). 1751 1752 .. warning:: 1753 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1754 to manually create snapshot images to attach to your blockdev). 1755 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1756 can use the 'snapshot' property on your drive declarations 1757 instead of this global option. 1758 1759ERST 1760 1761DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1762 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1763 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1764 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1765 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1766 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1767 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1768 " [[,throttling.iops-size=is]]\n" 1769 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1770 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1771 "-fsdev synth,id=id\n", 1772 QEMU_ARCH_ALL) 1773 1774SRST 1775``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1776 \ 1777``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1778 \ 1779``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1780 \ 1781``-fsdev synth,id=id[,readonly=on]`` 1782 Define a new file system device. Valid options are: 1783 1784 ``local`` 1785 Accesses to the filesystem are done by QEMU. 1786 1787 ``proxy`` 1788 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1789 option is deprecated (since QEMU 8.1) and will be removed in a future 1790 version of QEMU. Use ``local`` instead. 1791 1792 ``synth`` 1793 Synthetic filesystem, only used by QTests. 1794 1795 ``id=id`` 1796 Specifies identifier for this device. 1797 1798 ``path=path`` 1799 Specifies the export path for the file system device. Files 1800 under this path will be available to the 9p client on the guest. 1801 1802 ``security_model=security_model`` 1803 Specifies the security model to be used for this export path. 1804 Supported security models are "passthrough", "mapped-xattr", 1805 "mapped-file" and "none". In "passthrough" security model, files 1806 are stored using the same credentials as they are created on the 1807 guest. This requires QEMU to run as root. In "mapped-xattr" 1808 security model, some of the file attributes like uid, gid, mode 1809 bits and link target are stored as file attributes. For 1810 "mapped-file" these attributes are stored in the hidden 1811 .virtfs\_metadata directory. Directories exported by this 1812 security model cannot interact with other unix tools. "none" 1813 security model is same as passthrough except the sever won't 1814 report failures if it fails to set file attributes like 1815 ownership. Security model is mandatory only for local fsdriver. 1816 Other fsdrivers (like proxy) don't take security model as a 1817 parameter. 1818 1819 ``writeout=writeout`` 1820 This is an optional argument. The only supported value is 1821 "immediate". This means that host page cache will be used to 1822 read and write data but write notification will be sent to the 1823 guest only when the data has been reported as written by the 1824 storage subsystem. 1825 1826 ``readonly=on`` 1827 Enables exporting 9p share as a readonly mount for guests. By 1828 default read-write access is given. 1829 1830 ``socket=socket`` 1831 Enables proxy filesystem driver to use passed socket file for 1832 communicating with virtfs-proxy-helper(1). 1833 1834 ``sock_fd=sock_fd`` 1835 Enables proxy filesystem driver to use passed socket descriptor 1836 for communicating with virtfs-proxy-helper(1). Usually a helper 1837 like libvirt will create socketpair and pass one of the fds as 1838 sock\_fd. 1839 1840 ``fmode=fmode`` 1841 Specifies the default mode for newly created files on the host. 1842 Works only with security models "mapped-xattr" and 1843 "mapped-file". 1844 1845 ``dmode=dmode`` 1846 Specifies the default mode for newly created directories on the 1847 host. Works only with security models "mapped-xattr" and 1848 "mapped-file". 1849 1850 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1851 Specify bandwidth throttling limits in bytes per second, either 1852 for all request types or for reads or writes only. 1853 1854 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1855 Specify bursts in bytes per second, either for all request types 1856 or for reads or writes only. Bursts allow the guest I/O to spike 1857 above the limit temporarily. 1858 1859 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1860 Specify request rate limits in requests per second, either for 1861 all request types or for reads or writes only. 1862 1863 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1864 Specify bursts in requests per second, either for all request 1865 types or for reads or writes only. Bursts allow the guest I/O to 1866 spike above the limit temporarily. 1867 1868 ``throttling.iops-size=is`` 1869 Let every is bytes of a request count as a new request for iops 1870 throttling purposes. 1871 1872 -fsdev option is used along with -device driver "virtio-9p-...". 1873 1874``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1875 Options for virtio-9p-... driver are: 1876 1877 ``type`` 1878 Specifies the variant to be used. Supported values are "pci", 1879 "ccw" or "device", depending on the machine type. 1880 1881 ``fsdev=id`` 1882 Specifies the id value specified along with -fsdev option. 1883 1884 ``mount_tag=mount_tag`` 1885 Specifies the tag name to be used by the guest to mount this 1886 export point. 1887ERST 1888 1889DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1890 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1891 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1892 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1893 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1894 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1895 QEMU_ARCH_ALL) 1896 1897SRST 1898``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1899 \ 1900``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1901 \ 1902``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1903 \ 1904``-virtfs synth,mount_tag=mount_tag`` 1905 Define a new virtual filesystem device and expose it to the guest using 1906 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1907 directory on host is made directly accessible by guest as a pass-through 1908 file system by using the 9P network protocol for communication between 1909 host and guests, if desired even accessible, shared by several guests 1910 simultaneously. 1911 1912 Note that ``-virtfs`` is actually just a convenience shortcut for its 1913 generalized form ``-fsdev -device virtio-9p-pci``. 1914 1915 The general form of pass-through file system options are: 1916 1917 ``local`` 1918 Accesses to the filesystem are done by QEMU. 1919 1920 ``proxy`` 1921 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1922 This option is deprecated (since QEMU 8.1) and will be removed in a 1923 future version of QEMU. Use ``local`` instead. 1924 1925 ``synth`` 1926 Synthetic filesystem, only used by QTests. 1927 1928 ``id=id`` 1929 Specifies identifier for the filesystem device 1930 1931 ``path=path`` 1932 Specifies the export path for the file system device. Files 1933 under this path will be available to the 9p client on the guest. 1934 1935 ``security_model=security_model`` 1936 Specifies the security model to be used for this export path. 1937 Supported security models are "passthrough", "mapped-xattr", 1938 "mapped-file" and "none". In "passthrough" security model, files 1939 are stored using the same credentials as they are created on the 1940 guest. This requires QEMU to run as root. In "mapped-xattr" 1941 security model, some of the file attributes like uid, gid, mode 1942 bits and link target are stored as file attributes. For 1943 "mapped-file" these attributes are stored in the hidden 1944 .virtfs\_metadata directory. Directories exported by this 1945 security model cannot interact with other unix tools. "none" 1946 security model is same as passthrough except the sever won't 1947 report failures if it fails to set file attributes like 1948 ownership. Security model is mandatory only for local fsdriver. 1949 Other fsdrivers (like proxy) don't take security model as a 1950 parameter. 1951 1952 ``writeout=writeout`` 1953 This is an optional argument. The only supported value is 1954 "immediate". This means that host page cache will be used to 1955 read and write data but write notification will be sent to the 1956 guest only when the data has been reported as written by the 1957 storage subsystem. 1958 1959 ``readonly=on`` 1960 Enables exporting 9p share as a readonly mount for guests. By 1961 default read-write access is given. 1962 1963 ``socket=socket`` 1964 Enables proxy filesystem driver to use passed socket file for 1965 communicating with virtfs-proxy-helper(1). Usually a helper like 1966 libvirt will create socketpair and pass one of the fds as 1967 sock\_fd. 1968 1969 ``sock_fd`` 1970 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1971 socket descriptor for interfacing with virtfs-proxy-helper(1). 1972 1973 ``fmode=fmode`` 1974 Specifies the default mode for newly created files on the host. 1975 Works only with security models "mapped-xattr" and 1976 "mapped-file". 1977 1978 ``dmode=dmode`` 1979 Specifies the default mode for newly created directories on the 1980 host. Works only with security models "mapped-xattr" and 1981 "mapped-file". 1982 1983 ``mount_tag=mount_tag`` 1984 Specifies the tag name to be used by the guest to mount this 1985 export point. 1986 1987 ``multidevs=multidevs`` 1988 Specifies how to deal with multiple devices being shared with a 1989 9p export. Supported behaviours are either "remap", "forbid" or 1990 "warn". The latter is the default behaviour on which virtfs 9p 1991 expects only one device to be shared with the same export, and 1992 if more than one device is shared and accessed via the same 9p 1993 export then only a warning message is logged (once) by qemu on 1994 host side. In order to avoid file ID collisions on guest you 1995 should either create a separate virtfs export for each device to 1996 be shared with guests (recommended way) or you might use "remap" 1997 instead which allows you to share multiple devices with only one 1998 export instead, which is achieved by remapping the original 1999 inode numbers from host to guest in a way that would prevent 2000 such collisions. Remapping inodes in such use cases is required 2001 because the original device IDs from host are never passed and 2002 exposed on guest. Instead all files of an export shared with 2003 virtfs always share the same device id on guest. So two files 2004 with identical inode numbers but from actually different devices 2005 on host would otherwise cause a file ID collision and hence 2006 potential misbehaviours on guest. "forbid" on the other hand 2007 assumes like "warn" that only one device is shared by the same 2008 export, however it will not only log a warning message but also 2009 deny access to additional devices on guest. Note though that 2010 "forbid" does currently not block all possible file access 2011 operations (e.g. readdir() would still return entries from other 2012 devices). 2013ERST 2014 2015DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 2016 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 2017 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 2018 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 2019 " [,timeout=timeout]\n" 2020 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2021 2022SRST 2023``-iscsi`` 2024 Configure iSCSI session parameters. 2025ERST 2026 2027DEFHEADING() 2028 2029DEFHEADING(USB convenience options:) 2030 2031DEF("usb", 0, QEMU_OPTION_usb, 2032 "-usb enable on-board USB host controller (if not enabled by default)\n", 2033 QEMU_ARCH_ALL) 2034SRST 2035``-usb`` 2036 Enable USB emulation on machine types with an on-board USB host 2037 controller (if not enabled by default). Note that on-board USB host 2038 controllers may not support USB 3.0. In this case 2039 ``-device qemu-xhci`` can be used instead on machines with PCI. 2040ERST 2041 2042DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2043 "-usbdevice name add the host or guest USB device 'name'\n", 2044 QEMU_ARCH_ALL) 2045SRST 2046``-usbdevice devname`` 2047 Add the USB device devname, and enable an on-board USB controller 2048 if possible and necessary (just like it can be done via 2049 ``-machine usb=on``). Note that this option is mainly intended for 2050 the user's convenience only. More fine-grained control can be 2051 achieved by selecting a USB host controller (if necessary) and the 2052 desired USB device via the ``-device`` option instead. For example, 2053 instead of using ``-usbdevice mouse`` it is possible to use 2054 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2055 to a USB 3.0 controller instead (at least on machines that support 2056 PCI and do not have an USB controller enabled by default yet). 2057 For more details, see the chapter about 2058 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2059 Possible devices for devname are: 2060 2061 ``braille`` 2062 Braille device. This will use BrlAPI to display the braille 2063 output on a real or fake device (i.e. it also creates a 2064 corresponding ``braille`` chardev automatically beside the 2065 ``usb-braille`` USB device). 2066 2067 ``keyboard`` 2068 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2069 2070 ``mouse`` 2071 Virtual Mouse. This will override the PS/2 mouse emulation when 2072 activated. 2073 2074 ``tablet`` 2075 Pointer device that uses absolute coordinates (like a 2076 touchscreen). This means QEMU is able to report the mouse 2077 position without having to grab the mouse. Also overrides the 2078 PS/2 mouse emulation when activated. 2079 2080 ``wacom-tablet`` 2081 Wacom PenPartner USB tablet. 2082 2083 2084ERST 2085 2086DEFHEADING() 2087 2088DEFHEADING(Display options:) 2089 2090DEF("display", HAS_ARG, QEMU_OPTION_display, 2091#if defined(CONFIG_SPICE) 2092 "-display spice-app[,gl=on|off]\n" 2093#endif 2094#if defined(CONFIG_SDL) 2095 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2096 " [,window-close=on|off]\n" 2097#endif 2098#if defined(CONFIG_GTK) 2099 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2100 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2101 " [,show-menubar=on|off][,zoom-to-fit=on|off]\n" 2102#endif 2103#if defined(CONFIG_VNC) 2104 "-display vnc=<display>[,<optargs>]\n" 2105#endif 2106#if defined(CONFIG_CURSES) 2107 "-display curses[,charset=<encoding>]\n" 2108#endif 2109#if defined(CONFIG_COCOA) 2110 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2111 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2112 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2113#endif 2114#if defined(CONFIG_OPENGL) 2115 "-display egl-headless[,rendernode=<file>]\n" 2116#endif 2117#if defined(CONFIG_DBUS_DISPLAY) 2118 "-display dbus[,addr=<dbusaddr>]\n" 2119 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2120#endif 2121 "-display none\n" 2122 " select display backend type\n" 2123 " The default display is equivalent to\n " 2124#if defined(CONFIG_GTK) 2125 "\"-display gtk\"\n" 2126#elif defined(CONFIG_SDL) 2127 "\"-display sdl\"\n" 2128#elif defined(CONFIG_COCOA) 2129 "\"-display cocoa\"\n" 2130#elif defined(CONFIG_VNC) 2131 "\"-vnc localhost:0,to=99,id=default\"\n" 2132#else 2133 "\"-display none\"\n" 2134#endif 2135 , QEMU_ARCH_ALL) 2136SRST 2137``-display type`` 2138 Select type of display to use. Use ``-display help`` to list the available 2139 display types. Valid values for type are 2140 2141 ``spice-app[,gl=on|off]`` 2142 Start QEMU as a Spice server and launch the default Spice client 2143 application. The Spice server will redirect the serial consoles 2144 and QEMU monitors. (Since 4.0) 2145 2146 ``dbus`` 2147 Export the display over D-Bus interfaces. (Since 7.0) 2148 2149 The connection is registered with the "org.qemu" name (and queued when 2150 already owned). 2151 2152 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2153 2154 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2155 2156 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2157 will share framebuffers with DMABUF file descriptors). 2158 2159 ``sdl`` 2160 Display video output via SDL (usually in a separate graphics 2161 window; see the SDL documentation for other possibilities). 2162 Valid parameters are: 2163 2164 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2165 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2166 either ``lshift-lctrl-lalt`` or ``rctrl``. 2167 2168 ``gl=on|off|core|es`` : Use OpenGL for displaying 2169 2170 ``show-cursor=on|off`` : Force showing the mouse cursor 2171 2172 ``window-close=on|off`` : Allow to quit qemu with window close button 2173 2174 ``gtk`` 2175 Display video output in a GTK window. This interface provides 2176 drop-down menus and other UI elements to configure and control 2177 the VM during runtime. Valid parameters are: 2178 2179 ``full-screen=on|off`` : Start in fullscreen mode 2180 2181 ``gl=on|off`` : Use OpenGL for displaying 2182 2183 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2184 2185 ``show-tabs=on|off`` : Display the tab bar for switching between the 2186 various graphical interfaces (e.g. VGA and 2187 virtual console character devices) by default. 2188 2189 ``show-cursor=on|off`` : Force showing the mouse cursor 2190 2191 ``window-close=on|off`` : Allow to quit qemu with window close button 2192 2193 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2194 2195 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2196 defaults to "off" 2197 2198 ``curses[,charset=<encoding>]`` 2199 Display video output via curses. For graphics device models 2200 which support a text mode, QEMU can display this output using a 2201 curses/ncurses interface. Nothing is displayed when the graphics 2202 device is in graphical mode or if the graphics device does not 2203 support a text mode. Generally only the VGA device models 2204 support text mode. The font charset used by the guest can be 2205 specified with the ``charset`` option, for example 2206 ``charset=CP850`` for IBM CP850 encoding. The default is 2207 ``CP437``. 2208 2209 ``cocoa`` 2210 Display video output in a Cocoa window. Mac only. This interface 2211 provides drop-down menus and other UI elements to configure and 2212 control the VM during runtime. Valid parameters are: 2213 2214 ``full-grab=on|off`` : Capture all key presses, including system combos. 2215 This requires accessibility permissions, since it 2216 performs a global grab on key events. 2217 (default: off) See 2218 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2219 2220 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2221 key codes match their position on non-Mac 2222 keyboards and you can use Meta/Super and Alt 2223 where you expect them. (default: off) 2224 2225 ``show-cursor=on|off`` : Force showing the mouse cursor 2226 2227 ``left-command-key=on|off`` : Disable forwarding left command key to host 2228 2229 ``full-screen=on|off`` : Start in fullscreen mode 2230 2231 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2232 defaults to "off" 2233 2234 ``egl-headless[,rendernode=<file>]`` 2235 Offload all OpenGL operations to a local DRI device. For any 2236 graphical display, this display needs to be paired with either 2237 VNC or SPICE displays. 2238 2239 ``vnc=<display>`` 2240 Start a VNC server on display <display> 2241 2242 ``none`` 2243 Do not display video output. The guest will still see an 2244 emulated graphics card, but its output will not be displayed to 2245 the QEMU user. This option differs from the -nographic option in 2246 that it only affects what is done with video output; -nographic 2247 also changes the destination of the serial and parallel port 2248 data. 2249ERST 2250 2251DEF("nographic", 0, QEMU_OPTION_nographic, 2252 "-nographic disable graphical output and redirect serial I/Os to console\n", 2253 QEMU_ARCH_ALL) 2254SRST 2255``-nographic`` 2256 Normally, if QEMU is compiled with graphical window support, it 2257 displays output such as guest graphics, guest console, and the QEMU 2258 monitor in a window. With this option, you can totally disable 2259 graphical output so that QEMU is a simple command line application. 2260 The emulated serial port is redirected on the console and muxed with 2261 the monitor (unless redirected elsewhere explicitly). Therefore, you 2262 can still use QEMU to debug a Linux kernel with a serial console. 2263 Use C-a h for help on switching between the console and monitor. 2264ERST 2265 2266#ifdef CONFIG_SPICE 2267DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2268 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2269 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2270 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2271 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2272 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2273 " [,tls-ciphers=<list>]\n" 2274 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2275 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2276 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2277 " [,password-secret=<secret-id>]\n" 2278 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2279 " [,jpeg-wan-compression=[auto|never|always]]\n" 2280 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2281 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2282 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2283 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2284 " [,gl=[on|off]][,rendernode=<file>]\n" 2285 " enable spice\n" 2286 " at least one of {port, tls-port} is mandatory\n", 2287 QEMU_ARCH_ALL) 2288#endif 2289SRST 2290``-spice option[,option[,...]]`` 2291 Enable the spice remote desktop protocol. Valid options are 2292 2293 ``port=<nr>`` 2294 Set the TCP port spice is listening on for plaintext channels. 2295 2296 ``addr=<addr>`` 2297 Set the IP address spice is listening on. Default is any 2298 address. 2299 2300 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2301 Force using the specified IP version. 2302 2303 ``password-secret=<secret-id>`` 2304 Set the ID of the ``secret`` object containing the password 2305 you need to authenticate. 2306 2307 ``sasl=on|off`` 2308 Require that the client use SASL to authenticate with the spice. 2309 The exact choice of authentication method used is controlled 2310 from the system / user's SASL configuration file for the 'qemu' 2311 service. This is typically found in /etc/sasl2/qemu.conf. If 2312 running QEMU as an unprivileged user, an environment variable 2313 SASL\_CONF\_PATH can be used to make it search alternate 2314 locations for the service config. While some SASL auth methods 2315 can also provide data encryption (eg GSSAPI), it is recommended 2316 that SASL always be combined with the 'tls' and 'x509' settings 2317 to enable use of SSL and server certificates. This ensures a 2318 data encryption preventing compromise of authentication 2319 credentials. 2320 2321 ``disable-ticketing=on|off`` 2322 Allow client connects without authentication. 2323 2324 ``disable-copy-paste=on|off`` 2325 Disable copy paste between the client and the guest. 2326 2327 ``disable-agent-file-xfer=on|off`` 2328 Disable spice-vdagent based file-xfer between the client and the 2329 guest. 2330 2331 ``tls-port=<nr>`` 2332 Set the TCP port spice is listening on for encrypted channels. 2333 2334 ``x509-dir=<dir>`` 2335 Set the x509 file directory. Expects same filenames as -vnc 2336 $display,x509=$dir 2337 2338 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2339 The x509 file names can also be configured individually. 2340 2341 ``tls-ciphers=<list>`` 2342 Specify which ciphers to use. 2343 2344 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2345 Force specific channel to be used with or without TLS 2346 encryption. The options can be specified multiple times to 2347 configure multiple channels. The special name "default" can be 2348 used to set the default mode. For channels which are not 2349 explicitly forced into one mode the spice client is allowed to 2350 pick tls/plaintext as he pleases. 2351 2352 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2353 Configure image compression (lossless). Default is auto\_glz. 2354 2355 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2356 Configure wan image compression (lossy for slow links). Default 2357 is auto. 2358 2359 ``streaming-video=[off|all|filter]`` 2360 Configure video stream detection. Default is off. 2361 2362 ``agent-mouse=[on|off]`` 2363 Enable/disable passing mouse events via vdagent. Default is on. 2364 2365 ``playback-compression=[on|off]`` 2366 Enable/disable audio stream compression (using celt 0.5.1). 2367 Default is on. 2368 2369 ``seamless-migration=[on|off]`` 2370 Enable/disable spice seamless migration. Default is off. 2371 2372 ``gl=[on|off]`` 2373 Enable/disable OpenGL context. Default is off. 2374 2375 ``rendernode=<file>`` 2376 DRM render node for OpenGL rendering. If not specified, it will 2377 pick the first available. (Since 2.9) 2378ERST 2379 2380DEF("portrait", 0, QEMU_OPTION_portrait, 2381 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2382 QEMU_ARCH_ALL) 2383SRST 2384``-portrait`` 2385 Rotate graphical output 90 deg left (only PXA LCD). 2386ERST 2387 2388DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2389 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2390 QEMU_ARCH_ALL) 2391SRST 2392``-rotate deg`` 2393 Rotate graphical output some deg left (only PXA LCD). 2394ERST 2395 2396DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2397 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2398 " select video card type\n", QEMU_ARCH_ALL) 2399SRST 2400``-vga type`` 2401 Select type of VGA card to emulate. Valid values for type are 2402 2403 ``cirrus`` 2404 Cirrus Logic GD5446 Video card. All Windows versions starting 2405 from Windows 95 should recognize and use this graphic card. For 2406 optimal performances, use 16 bit color depth in the guest and 2407 the host OS. (This card was the default before QEMU 2.2) 2408 2409 ``std`` 2410 Standard VGA card with Bochs VBE extensions. If your guest OS 2411 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2412 you want to use high resolution modes (>= 1280x1024x16) then you 2413 should use this option. (This card is the default since QEMU 2414 2.2) 2415 2416 ``vmware`` 2417 VMWare SVGA-II compatible adapter. Use it if you have 2418 sufficiently recent XFree86/XOrg server or Windows guest with a 2419 driver for this card. 2420 2421 ``qxl`` 2422 QXL paravirtual graphic card. It is VGA compatible (including 2423 VESA 2.0 VBE support). Works best with qxl guest drivers 2424 installed though. Recommended choice when using the spice 2425 protocol. 2426 2427 ``tcx`` 2428 (sun4m only) Sun TCX framebuffer. This is the default 2429 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2430 colour depths at a fixed resolution of 1024x768. 2431 2432 ``cg3`` 2433 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2434 framebuffer for sun4m machines available in both 1024x768 2435 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2436 wishing to run older Solaris versions. 2437 2438 ``virtio`` 2439 Virtio VGA card. 2440 2441 ``none`` 2442 Disable VGA card. 2443ERST 2444 2445DEF("full-screen", 0, QEMU_OPTION_full_screen, 2446 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2447SRST 2448``-full-screen`` 2449 Start in full screen. 2450ERST 2451 2452DEF("g", HAS_ARG, QEMU_OPTION_g , 2453 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2454 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2455SRST 2456``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2457 Set the initial graphical resolution and depth (PPC, SPARC only). 2458 2459 For PPC the default is 800x600x32. 2460 2461 For SPARC with the TCX graphics device, the default is 1024x768x8 2462 with the option of 1024x768x24. For cgthree, the default is 2463 1024x768x8 with the option of 1152x900x8 for people who wish to use 2464 OBP. 2465ERST 2466 2467#ifdef CONFIG_VNC 2468DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2469 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2470#endif 2471SRST 2472``-vnc display[,option[,option[,...]]]`` 2473 Normally, if QEMU is compiled with graphical window support, it 2474 displays output such as guest graphics, guest console, and the QEMU 2475 monitor in a window. With this option, you can have QEMU listen on 2476 VNC display display and redirect the VGA display over the VNC 2477 session. It is very useful to enable the usb tablet device when 2478 using this option (option ``-device usb-tablet``). When using the 2479 VNC display, you must use the ``-k`` parameter to set the keyboard 2480 layout if you are not using en-us. Valid syntax for the display is 2481 2482 ``to=L`` 2483 With this option, QEMU will try next available VNC displays, 2484 until the number L, if the originally defined "-vnc display" is 2485 not available, e.g. port 5900+display is already used by another 2486 application. By default, to=0. 2487 2488 ``host:d`` 2489 TCP connections will only be allowed from host on display d. By 2490 convention the TCP port is 5900+d. Optionally, host can be 2491 omitted in which case the server will accept connections from 2492 any host. 2493 2494 ``unix:path`` 2495 Connections will be allowed over UNIX domain sockets where path 2496 is the location of a unix socket to listen for connections on. 2497 2498 ``none`` 2499 VNC is initialized but not started. The monitor ``change`` 2500 command can be used to later start the VNC server. 2501 2502 Following the display value there may be one or more option flags 2503 separated by commas. Valid options are 2504 2505 ``reverse=on|off`` 2506 Connect to a listening VNC client via a "reverse" connection. 2507 The client is specified by the display. For reverse network 2508 connections (host:d,``reverse``), the d argument is a TCP port 2509 number, not a display number. 2510 2511 ``websocket=on|off`` 2512 Opens an additional TCP listening port dedicated to VNC 2513 Websocket connections. If a bare websocket option is given, the 2514 Websocket port is 5700+display. An alternative port can be 2515 specified with the syntax ``websocket``\ =port. 2516 2517 If host is specified connections will only be allowed from this 2518 host. It is possible to control the websocket listen address 2519 independently, using the syntax ``websocket``\ =host:port. 2520 2521 Websocket could be allowed over UNIX domain socket, using the syntax 2522 ``websocket``\ =unix:path, where path is the location of a unix socket 2523 to listen for connections on. 2524 2525 If no TLS credentials are provided, the websocket connection 2526 runs in unencrypted mode. If TLS credentials are provided, the 2527 websocket connection requires encrypted client connections. 2528 2529 ``password=on|off`` 2530 Require that password based authentication is used for client 2531 connections. 2532 2533 The password must be set separately using the ``set_password`` 2534 command in the :ref:`QEMU monitor`. The 2535 syntax to change your password is: 2536 ``set_password <protocol> <password>`` where <protocol> could be 2537 either "vnc" or "spice". 2538 2539 If you would like to change <protocol> password expiration, you 2540 should use ``expire_password <protocol> <expiration-time>`` 2541 where expiration time could be one of the following options: 2542 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2543 make password expire in 60 seconds, or 1335196800 to make 2544 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2545 this date and time). 2546 2547 You can also use keywords "now" or "never" for the expiration 2548 time to allow <protocol> password to expire immediately or never 2549 expire. 2550 2551 ``password-secret=<secret-id>`` 2552 Require that password based authentication is used for client 2553 connections, using the password provided by the ``secret`` 2554 object identified by ``secret-id``. 2555 2556 ``tls-creds=ID`` 2557 Provides the ID of a set of TLS credentials to use to secure the 2558 VNC server. They will apply to both the normal VNC server socket 2559 and the websocket socket (if enabled). Setting TLS credentials 2560 will cause the VNC server socket to enable the VeNCrypt auth 2561 mechanism. The credentials should have been previously created 2562 using the ``-object tls-creds`` argument. 2563 2564 ``tls-authz=ID`` 2565 Provides the ID of the QAuthZ authorization object against which 2566 the client's x509 distinguished name will validated. This object 2567 is only resolved at time of use, so can be deleted and recreated 2568 on the fly while the VNC server is active. If missing, it will 2569 default to denying access. 2570 2571 ``sasl=on|off`` 2572 Require that the client use SASL to authenticate with the VNC 2573 server. The exact choice of authentication method used is 2574 controlled from the system / user's SASL configuration file for 2575 the 'qemu' service. This is typically found in 2576 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2577 an environment variable SASL\_CONF\_PATH can be used to make it 2578 search alternate locations for the service config. While some 2579 SASL auth methods can also provide data encryption (eg GSSAPI), 2580 it is recommended that SASL always be combined with the 'tls' 2581 and 'x509' settings to enable use of SSL and server 2582 certificates. This ensures a data encryption preventing 2583 compromise of authentication credentials. See the 2584 :ref:`VNC security` section in the System Emulation Users Guide 2585 for details on using SASL authentication. 2586 2587 ``sasl-authz=ID`` 2588 Provides the ID of the QAuthZ authorization object against which 2589 the client's SASL username will validated. This object is only 2590 resolved at time of use, so can be deleted and recreated on the 2591 fly while the VNC server is active. If missing, it will default 2592 to denying access. 2593 2594 ``acl=on|off`` 2595 Legacy method for enabling authorization of clients against the 2596 x509 distinguished name and SASL username. It results in the 2597 creation of two ``authz-list`` objects with IDs of 2598 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2599 objects must be configured with the HMP ACL commands. 2600 2601 This option is deprecated and should no longer be used. The new 2602 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2603 2604 ``lossy=on|off`` 2605 Enable lossy compression methods (gradient, JPEG, ...). If this 2606 option is set, VNC client may receive lossy framebuffer updates 2607 depending on its encoding settings. Enabling this option can 2608 save a lot of bandwidth at the expense of quality. 2609 2610 ``non-adaptive=on|off`` 2611 Disable adaptive encodings. Adaptive encodings are enabled by 2612 default. An adaptive encoding will try to detect frequently 2613 updated screen regions, and send updates in these regions using 2614 a lossy encoding (like JPEG). This can be really helpful to save 2615 bandwidth when playing videos. Disabling adaptive encodings 2616 restores the original static behavior of encodings like Tight. 2617 2618 ``share=[allow-exclusive|force-shared|ignore]`` 2619 Set display sharing policy. 'allow-exclusive' allows clients to 2620 ask for exclusive access. As suggested by the rfb spec this is 2621 implemented by dropping other connections. Connecting multiple 2622 clients in parallel requires all clients asking for a shared 2623 session (vncviewer: -shared switch). This is the default. 2624 'force-shared' disables exclusive client access. Useful for 2625 shared desktop sessions, where you don't want someone forgetting 2626 specify -shared disconnect everybody else. 'ignore' completely 2627 ignores the shared flag and allows everybody connect 2628 unconditionally. Doesn't conform to the rfb spec but is 2629 traditional QEMU behavior. 2630 2631 ``key-delay-ms`` 2632 Set keyboard delay, for key down and key up events, in 2633 milliseconds. Default is 10. Keyboards are low-bandwidth 2634 devices, so this slowdown can help the device and guest to keep 2635 up and not lose events in case events are arriving in bulk. 2636 Possible causes for the latter are flaky network connections, or 2637 scripts for automated testing. 2638 2639 ``audiodev=audiodev`` 2640 Use the specified audiodev when the VNC client requests audio 2641 transmission. When not using an -audiodev argument, this option 2642 must be omitted, otherwise is must be present and specify a 2643 valid audiodev. 2644 2645 ``power-control=on|off`` 2646 Permit the remote client to issue shutdown, reboot or reset power 2647 control requests. 2648ERST 2649 2650ARCHHEADING(, QEMU_ARCH_I386) 2651 2652ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2653 2654DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2655 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2656 QEMU_ARCH_I386) 2657SRST 2658``-win2k-hack`` 2659 Use it when installing Windows 2000 to avoid a disk full bug. After 2660 Windows 2000 is installed, you no longer need this option (this 2661 option slows down the IDE transfers). Synonym of ``-global 2662 ide-device.win2k-install-hack=on``. 2663ERST 2664 2665DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2666 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2667 QEMU_ARCH_I386) 2668SRST 2669``-no-fd-bootchk`` 2670 Disable boot signature checking for floppy disks in BIOS. May be 2671 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2672ERST 2673 2674DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2675 "-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" 2676 " ACPI table description\n", QEMU_ARCH_I386) 2677SRST 2678``-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]...]`` 2679 Add ACPI table with specified header fields and context from 2680 specified files. For file=, take whole ACPI table from the specified 2681 files, including all ACPI headers (possible overridden by other 2682 options). For data=, only data portion of the table is used, all 2683 header information is specified in the command line. If a SLIC table 2684 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2685 fields will override the same in the RSDT and the FADT (a.k.a. 2686 FACP), in order to ensure the field matches required by the 2687 Microsoft SLIC spec and the ACPI spec. 2688ERST 2689 2690DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2691 "-smbios file=binary\n" 2692 " load SMBIOS entry from binary file\n" 2693 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2694 " [,uefi=on|off]\n" 2695 " specify SMBIOS type 0 fields\n" 2696 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2697 " [,uuid=uuid][,sku=str][,family=str]\n" 2698 " specify SMBIOS type 1 fields\n" 2699 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2700 " [,asset=str][,location=str]\n" 2701 " specify SMBIOS type 2 fields\n" 2702 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2703 " [,sku=str]\n" 2704 " specify SMBIOS type 3 fields\n" 2705 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2706 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2707 " [,processor-family=%d,processor-id=%d]\n" 2708 " specify SMBIOS type 4 fields\n" 2709 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2710 " specify SMBIOS type 8 fields\n" 2711 "-smbios type=11[,value=str][,path=filename]\n" 2712 " specify SMBIOS type 11 fields\n" 2713 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2714 " [,asset=str][,part=str][,speed=%d]\n" 2715 " specify SMBIOS type 17 fields\n" 2716 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2717 " specify SMBIOS type 41 fields\n", 2718 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2719SRST 2720``-smbios file=binary`` 2721 Load SMBIOS entry from binary file. 2722 2723``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2724 Specify SMBIOS type 0 fields 2725 2726``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2727 Specify SMBIOS type 1 fields 2728 2729``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2730 Specify SMBIOS type 2 fields 2731 2732``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2733 Specify SMBIOS type 3 fields 2734 2735``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2736 Specify SMBIOS type 4 fields 2737 2738``-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]`` 2739 Specify SMBIOS type 9 fields 2740 2741``-smbios type=11[,value=str][,path=filename]`` 2742 Specify SMBIOS type 11 fields 2743 2744 This argument can be repeated multiple times, and values are added in the order they are parsed. 2745 Applications intending to use OEM strings data are encouraged to use their application name as 2746 a prefix for the value string. This facilitates passing information for multiple applications 2747 concurrently. 2748 2749 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2750 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2751 2752 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2753 the SMBIOS table in the order in which they appear. 2754 2755 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2756 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2757 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2758 data set, for example, by specifying the serial ID of a block device. 2759 2760 An example passing three strings is 2761 2762 .. parsed-literal:: 2763 2764 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2765 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2766 path=/some/file/with/oemstringsdata.txt 2767 2768 In the guest OS this is visible with the ``dmidecode`` command 2769 2770 .. parsed-literal:: 2771 2772 $ dmidecode -t 11 2773 Handle 0x0E00, DMI type 11, 5 bytes 2774 OEM Strings 2775 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2776 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2777 String 3: myapp:some extra data 2778 2779 2780``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2781 Specify SMBIOS type 17 fields 2782 2783``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2784 Specify SMBIOS type 41 fields 2785 2786 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2787 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2788 position on the PCI bus. 2789 2790 Here is an example of use: 2791 2792 .. parsed-literal:: 2793 2794 -netdev user,id=internet \\ 2795 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2796 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2797 2798 In the guest OS, the device should then appear as ``eno1``: 2799 2800 ..parsed-literal:: 2801 2802 $ ip -brief l 2803 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2804 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2805 2806 Currently, the PCI device has to be attached to the root bus. 2807 2808ERST 2809 2810DEFHEADING() 2811 2812DEFHEADING(Network options:) 2813 2814DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2815#ifdef CONFIG_SLIRP 2816 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2817 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2818 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2819 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2820 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2821#ifndef _WIN32 2822 "[,smb=dir[,smbserver=addr]]\n" 2823#endif 2824 " configure a user mode network backend with ID 'str',\n" 2825 " its DHCP server and optional services\n" 2826#endif 2827#ifdef _WIN32 2828 "-netdev tap,id=str,ifname=name\n" 2829 " configure a host TAP network backend with ID 'str'\n" 2830#else 2831 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2832 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2833 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2834 " [,poll-us=n]\n" 2835 " configure a host TAP network backend with ID 'str'\n" 2836 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2837 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2838 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2839 " to deconfigure it\n" 2840 " use '[down]script=no' to disable script execution\n" 2841 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2842 " configure it\n" 2843 " use 'fd=h' to connect to an already opened TAP interface\n" 2844 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2845 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2846 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2847 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2848 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2849 " use vhost=on to enable experimental in kernel accelerator\n" 2850 " (only has effect for virtio guests which use MSIX)\n" 2851 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2852 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2853 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2854 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2855 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2856 " spent on busy polling for vhost net\n" 2857 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2858 " configure a host TAP network backend with ID 'str' that is\n" 2859 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2860 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2861#endif 2862#ifdef __linux__ 2863 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2864 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2865 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2866 " [,rxcookie=rxcookie][,offset=offset]\n" 2867 " configure a network backend with ID 'str' connected to\n" 2868 " an Ethernet over L2TPv3 pseudowire.\n" 2869 " Linux kernel 3.3+ as well as most routers can talk\n" 2870 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2871 " VM to a router and even VM to Host. It is a nearly-universal\n" 2872 " standard (RFC3931). Note - this implementation uses static\n" 2873 " pre-configured tunnels (same as the Linux kernel).\n" 2874 " use 'src=' to specify source address\n" 2875 " use 'dst=' to specify destination address\n" 2876 " use 'udp=on' to specify udp encapsulation\n" 2877 " use 'srcport=' to specify source udp port\n" 2878 " use 'dstport=' to specify destination udp port\n" 2879 " use 'ipv6=on' to force v6\n" 2880 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2881 " well as a weak security measure\n" 2882 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2883 " use 'txcookie=0x012345678' to specify a txcookie\n" 2884 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2885 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2886 " use 'pincounter=on' to work around broken counter handling in peer\n" 2887 " use 'offset=X' to add an extra offset between header and data\n" 2888#endif 2889 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2890 " configure a network backend to connect to another network\n" 2891 " using a socket connection\n" 2892 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2893 " configure a network backend to connect to a multicast maddr and port\n" 2894 " use 'localaddr=addr' to specify the host address to send packets from\n" 2895 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2896 " configure a network backend to connect to another network\n" 2897 " using an UDP tunnel\n" 2898 "-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" 2899 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2900 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2901 " configure a network backend to connect to another network\n" 2902 " using a socket connection in stream mode.\n" 2903 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2904 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2905 " configure a network backend to connect to a multicast maddr and port\n" 2906 " use ``local.host=addr`` to specify the host address to send packets from\n" 2907 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2908 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2909 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2910 " configure a network backend to connect to another network\n" 2911 " using an UDP tunnel\n" 2912#ifdef CONFIG_VDE 2913 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2914 " configure a network backend to connect to port 'n' of a vde switch\n" 2915 " running on host and listening for incoming connections on 'socketpath'.\n" 2916 " Use group 'groupname' and mode 'octalmode' to change default\n" 2917 " ownership and permissions for communication port.\n" 2918#endif 2919#ifdef CONFIG_NETMAP 2920 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2921 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2922 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2923 " netmap device, defaults to '/dev/netmap')\n" 2924#endif 2925#ifdef CONFIG_AF_XDP 2926 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2927 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2928 " attach to the existing network interface 'name' with AF_XDP socket\n" 2929 " use 'mode=MODE' to specify an XDP program attach mode\n" 2930 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2931 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2932 " with inhibit=on,\n" 2933 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2934 " added to a socket map in XDP program. One socket per queue.\n" 2935 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2936 " use 'start-queue=m' to specify the first queue that should be used\n" 2937#endif 2938#ifdef CONFIG_POSIX 2939 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2940 " configure a vhost-user network, backed by a chardev 'dev'\n" 2941#endif 2942#ifdef __linux__ 2943 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2944 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2945 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2946 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2947#endif 2948#ifdef CONFIG_VMNET 2949 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2950 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2951 " configure a vmnet network backend in host mode with ID 'str',\n" 2952 " isolate this interface from others with 'isolated',\n" 2953 " configure the address range and choose a subnet mask,\n" 2954 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2955 " vmnet-host interfaces within this isolated network\n" 2956 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2957 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2958 " configure a vmnet network backend in shared mode with ID 'str',\n" 2959 " configure the address range and choose a subnet mask,\n" 2960 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2961 " isolate this interface from others with 'isolated'\n" 2962 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2963 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2964 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2965 " isolate this interface from others with 'isolated'\n" 2966#endif 2967 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2968 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2969DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2970 "-nic [tap|bridge|" 2971#ifdef CONFIG_SLIRP 2972 "user|" 2973#endif 2974#ifdef __linux__ 2975 "l2tpv3|" 2976#endif 2977#ifdef CONFIG_VDE 2978 "vde|" 2979#endif 2980#ifdef CONFIG_NETMAP 2981 "netmap|" 2982#endif 2983#ifdef CONFIG_AF_XDP 2984 "af-xdp|" 2985#endif 2986#ifdef CONFIG_POSIX 2987 "vhost-user|" 2988#endif 2989#ifdef CONFIG_VMNET 2990 "vmnet-host|vmnet-shared|vmnet-bridged|" 2991#endif 2992 "socket][,option][,...][mac=macaddr]\n" 2993 " initialize an on-board / default host NIC (using MAC address\n" 2994 " macaddr) and connect it to the given host network backend\n" 2995 "-nic none use it alone to have zero network devices (the default is to\n" 2996 " provided a 'user' network connection)\n", 2997 QEMU_ARCH_ALL) 2998DEF("net", HAS_ARG, QEMU_OPTION_net, 2999 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 3000 " configure or create an on-board (or machine default) NIC and\n" 3001 " connect it to hub 0 (please use -nic unless you need a hub)\n" 3002 "-net [" 3003#ifdef CONFIG_SLIRP 3004 "user|" 3005#endif 3006 "tap|" 3007 "bridge|" 3008#ifdef CONFIG_VDE 3009 "vde|" 3010#endif 3011#ifdef CONFIG_NETMAP 3012 "netmap|" 3013#endif 3014#ifdef CONFIG_AF_XDP 3015 "af-xdp|" 3016#endif 3017#ifdef CONFIG_VMNET 3018 "vmnet-host|vmnet-shared|vmnet-bridged|" 3019#endif 3020 "socket][,option][,option][,...]\n" 3021 " old way to initialize a host network interface\n" 3022 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3023SRST 3024``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3025 This option is a shortcut for configuring both the on-board 3026 (default) guest NIC hardware and the host network backend in one go. 3027 The host backend options are the same as with the corresponding 3028 ``-netdev`` options below. The guest NIC model can be set with 3029 ``model=modelname``. Use ``model=help`` to list the available device 3030 types. The hardware MAC address can be set with ``mac=macaddr``. 3031 3032 The following two example do exactly the same, to show how ``-nic`` 3033 can be used to shorten the command line length: 3034 3035 .. parsed-literal:: 3036 3037 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3038 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3039 3040``-nic none`` 3041 Indicate that no network devices should be configured. It is used to 3042 override the default configuration (default NIC with "user" host 3043 network backend) which is activated if no other networking options 3044 are provided. 3045 3046``-netdev user,id=id[,option][,option][,...]`` 3047 Configure user mode host network backend which requires no 3048 administrator privilege to run. Valid options are: 3049 3050 ``id=id`` 3051 Assign symbolic name for use in monitor commands. 3052 3053 ``ipv4=on|off and ipv6=on|off`` 3054 Specify that either IPv4 or IPv6 must be enabled. If neither is 3055 specified both protocols are enabled. 3056 3057 ``net=addr[/mask]`` 3058 Set IP network address the guest will see. Optionally specify 3059 the netmask, either in the form a.b.c.d or as number of valid 3060 top-most bits. Default is 10.0.2.0/24. 3061 3062 ``host=addr`` 3063 Specify the guest-visible address of the host. Default is the 3064 2nd IP in the guest network, i.e. x.x.x.2. 3065 3066 ``ipv6-net=addr[/int]`` 3067 Set IPv6 network address the guest will see (default is 3068 fec0::/64). The network prefix is given in the usual hexadecimal 3069 IPv6 address notation. The prefix size is optional, and is given 3070 as the number of valid top-most bits (default is 64). 3071 3072 ``ipv6-host=addr`` 3073 Specify the guest-visible IPv6 address of the host. Default is 3074 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3075 3076 ``restrict=on|off`` 3077 If this option is enabled, the guest will be isolated, i.e. it 3078 will not be able to contact the host and no guest IP packets 3079 will be routed over the host to the outside. This option does 3080 not affect any explicitly set forwarding rules. 3081 3082 ``hostname=name`` 3083 Specifies the client hostname reported by the built-in DHCP 3084 server. 3085 3086 ``dhcpstart=addr`` 3087 Specify the first of the 16 IPs the built-in DHCP server can 3088 assign. Default is the 15th to 31st IP in the guest network, 3089 i.e. x.x.x.15 to x.x.x.31. 3090 3091 ``dns=addr`` 3092 Specify the guest-visible address of the virtual nameserver. The 3093 address must be different from the host address. Default is the 3094 3rd IP in the guest network, i.e. x.x.x.3. 3095 3096 ``ipv6-dns=addr`` 3097 Specify the guest-visible address of the IPv6 virtual 3098 nameserver. The address must be different from the host address. 3099 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3100 3101 ``dnssearch=domain`` 3102 Provides an entry for the domain-search list sent by the 3103 built-in DHCP server. More than one domain suffix can be 3104 transmitted by specifying this option multiple times. If 3105 supported, this will cause the guest to automatically try to 3106 append the given domain suffix(es) in case a domain name can not 3107 be resolved. 3108 3109 Example: 3110 3111 .. parsed-literal:: 3112 3113 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3114 3115 ``domainname=domain`` 3116 Specifies the client domain name reported by the built-in DHCP 3117 server. 3118 3119 ``tftp=dir`` 3120 When using the user mode network stack, activate a built-in TFTP 3121 server. The files in dir will be exposed as the root of a TFTP 3122 server. The TFTP client on the guest must be configured in 3123 binary mode (use the command ``bin`` of the Unix TFTP client). 3124 The built-in TFTP server is read-only; it does not implement any 3125 command for writing files. QEMU will not write to this directory. 3126 3127 ``tftp-server-name=name`` 3128 In BOOTP reply, broadcast name as the "TFTP server name" 3129 (RFC2132 option 66). This can be used to advise the guest to 3130 load boot files or configurations from a different server than 3131 the host address. 3132 3133 ``bootfile=file`` 3134 When using the user mode network stack, broadcast file as the 3135 BOOTP filename. In conjunction with ``tftp``, this can be used 3136 to network boot a guest from a local directory. 3137 3138 Example (using pxelinux): 3139 3140 .. parsed-literal:: 3141 3142 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3143 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3144 3145 ``smb=dir[,smbserver=addr]`` 3146 When using the user mode network stack, activate a built-in SMB 3147 server so that Windows OSes can access to the host files in 3148 ``dir`` transparently. The IP address of the SMB server can be 3149 set to addr. By default the 4th IP in the guest network is used, 3150 i.e. x.x.x.4. 3151 3152 In the guest Windows OS, the line: 3153 3154 :: 3155 3156 10.0.2.4 smbserver 3157 3158 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3159 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3160 NT/2000). 3161 3162 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3163 3164 Note that a SAMBA server must be installed on the host OS. 3165 3166 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3167 Redirect incoming TCP or UDP connections to the host port 3168 hostport to the guest IP address guestaddr on guest port 3169 guestport. If guestaddr is not specified, its value is x.x.x.15 3170 (default first address given by the built-in DHCP server). By 3171 specifying hostaddr, the rule can be bound to a specific host 3172 interface. If no connection type is set, TCP is used. This 3173 option can be given multiple times. 3174 3175 For example, to redirect host X11 connection from screen 1 to 3176 guest screen 0, use the following: 3177 3178 .. parsed-literal:: 3179 3180 # on the host 3181 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3182 # this host xterm should open in the guest X11 server 3183 xterm -display :1 3184 3185 To redirect telnet connections from host port 5555 to telnet 3186 port on the guest, use the following: 3187 3188 .. parsed-literal:: 3189 3190 # on the host 3191 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3192 telnet localhost 5555 3193 3194 Then when you use on the host ``telnet localhost 5555``, you 3195 connect to the guest telnet server. 3196 3197 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3198 Forward guest TCP connections to the IP address server on port 3199 port to the character device dev or to a program executed by 3200 cmd:command which gets spawned for each connection. This option 3201 can be given multiple times. 3202 3203 You can either use a chardev directly and have that one used 3204 throughout QEMU's lifetime, like in the following example: 3205 3206 .. parsed-literal:: 3207 3208 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3209 # the guest accesses it 3210 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3211 3212 Or you can execute a command on every TCP connection established 3213 by the guest, so that QEMU behaves similar to an inetd process 3214 for that virtual server: 3215 3216 .. parsed-literal:: 3217 3218 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3219 # and connect the TCP stream to its stdin/stdout 3220 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3221 3222``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3223 Configure a host TAP network backend with ID id. 3224 3225 Use the network script file to configure it and the network script 3226 dfile to deconfigure it. If name is not provided, the OS 3227 automatically provides one. The default network configure script is 3228 ``/etc/qemu-ifup`` and the default network deconfigure script is 3229 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3230 disable script execution. 3231 3232 If running QEMU as an unprivileged user, use the network helper 3233 to configure the TAP interface and attach it to the bridge. 3234 The default network helper executable is 3235 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3236 ``br0``. 3237 3238 ``fd``\ =h can be used to specify the handle of an already opened 3239 host TAP interface. 3240 3241 Examples: 3242 3243 .. parsed-literal:: 3244 3245 #launch a QEMU instance with the default network script 3246 |qemu_system| linux.img -nic tap 3247 3248 .. parsed-literal:: 3249 3250 #launch a QEMU instance with two NICs, each one connected 3251 #to a TAP device 3252 |qemu_system| linux.img \\ 3253 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3254 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 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 -device virtio-net-pci,netdev=n1 \\ 3261 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3262 3263``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3264 Connect a host TAP network interface to a host bridge device. 3265 3266 Use the network helper helper to configure the TAP interface and 3267 attach it to the bridge. The default network helper executable is 3268 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3269 ``br0``. 3270 3271 Examples: 3272 3273 .. parsed-literal:: 3274 3275 #launch a QEMU instance with the default network helper to 3276 #connect a TAP device to bridge br0 3277 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3278 3279 .. parsed-literal:: 3280 3281 #launch a QEMU instance with the default network helper to 3282 #connect a TAP device to bridge qemubr0 3283 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3284 3285``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3286 This host network backend can be used to connect the guest's network 3287 to another QEMU virtual machine using a TCP socket connection. If 3288 ``listen`` is specified, QEMU waits for incoming connections on port 3289 (host is optional). ``connect`` is used to connect to another QEMU 3290 instance using the ``listen`` option. ``fd``\ =h specifies an 3291 already opened TCP socket. 3292 3293 Example: 3294 3295 .. parsed-literal:: 3296 3297 # launch a first QEMU instance 3298 |qemu_system| linux.img \\ 3299 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3300 -netdev socket,id=n1,listen=:1234 3301 # connect the network of this instance to the network of the first instance 3302 |qemu_system| linux.img \\ 3303 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3304 -netdev socket,id=n2,connect=127.0.0.1:1234 3305 3306``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3307 Configure a socket host network backend to share the guest's network 3308 traffic with another QEMU virtual machines using a UDP multicast 3309 socket, effectively making a bus for every QEMU with same multicast 3310 address maddr and port. NOTES: 3311 3312 1. Several QEMU can be running on different hosts and share same bus 3313 (assuming correct multicast setup for these hosts). 3314 3315 2. mcast support is compatible with User Mode Linux (argument 3316 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3317 3318 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3319 3320 Example: 3321 3322 .. parsed-literal:: 3323 3324 # launch one QEMU instance 3325 |qemu_system| linux.img \\ 3326 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3327 -netdev socket,id=n1,mcast=230.0.0.1:1234 3328 # launch another QEMU instance on same "bus" 3329 |qemu_system| linux.img \\ 3330 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3331 -netdev socket,id=n2,mcast=230.0.0.1:1234 3332 # launch yet another QEMU instance on same "bus" 3333 |qemu_system| linux.img \\ 3334 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3335 -netdev socket,id=n3,mcast=230.0.0.1:1234 3336 3337 Example (User Mode Linux compat.): 3338 3339 .. parsed-literal:: 3340 3341 # launch QEMU instance (note mcast address selected is UML's default) 3342 |qemu_system| linux.img \\ 3343 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3344 -netdev socket,id=n1,mcast=239.192.168.1:1102 3345 # launch UML 3346 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3347 3348 Example (send packets from host's 1.2.3.4): 3349 3350 .. parsed-literal:: 3351 3352 |qemu_system| linux.img \\ 3353 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3354 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3355 3356``-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]`` 3357 Configure a network backend to connect to another QEMU virtual machine or a proxy using a TCP/IP socket. 3358 3359 ``server=on|off`` 3360 if ``on`` create a server socket 3361 3362 ``addr.host=host,addr.port=port`` 3363 socket address to listen on (server=on) or connect to (server=off) 3364 3365 ``to=maxport`` 3366 if present, this is range of possible addresses, with port between ``port`` and ``maxport``. 3367 3368 ``numeric=on|off`` 3369 if ``on`` ``host`` and ``port`` are guaranteed to be numeric, otherwise a name resolution should be attempted (default: ``off``) 3370 3371 ``keep-alive=on|off`` 3372 enable keep-alive when connecting to this socket. Not supported for passive sockets. 3373 3374 ``mptcp=on|off`` 3375 enable multipath TCP 3376 3377 ``ipv4=on|off`` 3378 whether to accept IPv4 addresses, default to try both IPv4 and IPv6 3379 3380 ``ipv6=on|off`` 3381 whether to accept IPv6 addresses, default to try both IPv4 and IPv6 3382 3383 ``reconnect=seconds`` 3384 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds. 3385 Setting this to zero disables this function. (default: 0) 3386 3387 Example (two guests connected using a TCP/IP socket): 3388 3389 .. parsed-literal:: 3390 3391 # first VM 3392 |qemu_system| linux.img \\ 3393 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3394 -netdev stream,id=net0,server=on,addr.type=inet,addr.host=localhost,addr.port=1234 3395 # second VM 3396 |qemu_system| linux.img \\ 3397 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3398 -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234,reconnect=5 3399 3400``-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]`` 3401 Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented unix domain socket. 3402 3403 ``server=on|off`` 3404 if ``on`` create a server socket 3405 3406 ``addr.path=path`` 3407 filesystem path to use 3408 3409 ``abstract=on|off`` 3410 if ``on``, this is a Linux abstract socket address. 3411 3412 ``tight=on|off`` 3413 if false, pad an abstract socket address with enough null bytes to make it fill struct sockaddr_un member sun_path. 3414 3415 ``reconnect=seconds`` 3416 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds. 3417 Setting this to zero disables this function. (default: 0) 3418 3419 Example (using passt as a replacement of -netdev user): 3420 3421 .. parsed-literal:: 3422 3423 # start passt server as a non privileged user 3424 passt 3425 UNIX domain socket bound at /tmp/passt_1.socket 3426 # start QEMU to connect to passt 3427 |qemu_system| linux.img \\ 3428 -device virtio-net,netdev=net0 \\ 3429 -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/passt_1.socket 3430 3431 Example (two guests connected using a stream oriented unix domain socket): 3432 3433 .. parsed-literal:: 3434 3435 # first VM 3436 |qemu_system| linux.img \\ 3437 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3438 netdev stream,id=net0,server=on,addr.type=unix,addr.path=/tmp/qemu0 3439 # second VM 3440 |qemu_system| linux.img \\ 3441 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3442 -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/qemu0,reconnect=5 3443 3444``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]`` 3445 Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented socket file descriptor. 3446 3447 ``server=on|off`` 3448 if ``on`` create a server socket 3449 3450 ``addr.str=file-descriptor`` 3451 file descriptor number to use as a socket 3452 3453 ``reconnect=seconds`` 3454 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds. 3455 Setting this to zero disables this function. (default: 0) 3456 3457``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]`` 3458 Configure a network backend to connect to a multicast address. 3459 3460 ``remote.host=maddr,remote.port=port`` 3461 multicast address 3462 3463 ``local.host=addr`` 3464 specify the host address to send packets from 3465 3466 Example: 3467 3468 .. parsed-literal:: 3469 3470 # launch one QEMU instance 3471 |qemu_system| linux.img \\ 3472 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3473 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3474 # launch another QEMU instance on same "bus" 3475 |qemu_system| linux.img \\ 3476 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3477 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3478 # launch yet another QEMU instance on same "bus" 3479 |qemu_system| linux.img \\ 3480 -device virtio-net,netdev=net0,mac=52:54:00:12:34:58 \\ 3481 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3482 3483``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]`` 3484 Configure a network backend to connect to a multicast address using a UDP socket file descriptor. 3485 3486 ``remote.host=maddr,remote.port=port`` 3487 multicast address 3488 3489 ``local.str=file-descriptor`` 3490 File descriptor to use to send packets 3491 3492``-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]`` 3493 Configure a network backend to connect to another QEMU virtual 3494 machine or a proxy using a datagram oriented unix domain socket. 3495 3496 ``local.host=addr,local.port=port`` 3497 IP address to use to send the packets from 3498 3499 ``remote.host=addr,remote.port=port`` 3500 Destination IP address 3501 3502 Example (two guests connected using an UDP/IP socket): 3503 3504 .. parsed-literal:: 3505 3506 # first VM 3507 |qemu_system| linux.img \\ 3508 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3509 -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1234,remote.type=inet,remote.host=localhost,remote.port=1235 3510 # second VM 3511 |qemu_system| linux.img \\ 3512 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3513 -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1235,remote.type=inet,remote.host=localhost,remote.port=1234 3514 3515``-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]`` 3516 Configure a network backend to connect to another QEMU virtual 3517 machine or a proxy using a datagram oriented unix socket. 3518 3519 ``local.path=path`` 3520 filesystem path to use to bind the socket 3521 3522 ``remote.path=path`` 3523 filesystem path to use as a destination (see sendto(2)) 3524 3525 Example (two guests connected using an UDP/UNIX socket): 3526 3527 .. parsed-literal:: 3528 3529 # first VM 3530 |qemu_system| linux.img \\ 3531 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3532 -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu0,remote.type=unix,remote.path=/tmp/qemu1 3533 # second VM 3534 |qemu_system| linux.img \\ 3535 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3536 -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu1,remote.type=unix,remote.path=/tmp/qemu0 3537 3538``-netdev dgram,id=str,local.type=fd,local.str=file-descriptor`` 3539 Configure a network backend to connect to another QEMU virtual 3540 machine or a proxy using a datagram oriented socket file descriptor. 3541 3542 ``local.str=file-descriptor`` 3543 File descriptor to use to send packets 3544 3545``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64=on|off][,counter=on|off][,pincounter=on|off][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 3546 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3547 is a popular protocol to transport Ethernet (and other Layer 2) data 3548 frames between two systems. It is present in routers, firewalls and 3549 the Linux kernel (from version 3.3 onwards). 3550 3551 This transport allows a VM to communicate to another VM, router or 3552 firewall directly. 3553 3554 ``src=srcaddr`` 3555 source address (mandatory) 3556 3557 ``dst=dstaddr`` 3558 destination address (mandatory) 3559 3560 ``udp=on`` 3561 select udp encapsulation (default is ip). 3562 3563 ``srcport=srcport`` 3564 source udp port. 3565 3566 ``dstport=dstport`` 3567 destination udp port. 3568 3569 ``ipv6=on`` 3570 force v6, otherwise defaults to v4. 3571 3572 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3573 Cookies are a weak form of security in the l2tpv3 specification. 3574 Their function is mostly to prevent misconfiguration. By default 3575 they are 32 bit. 3576 3577 ``cookie64=on`` 3578 Set cookie size to 64 bit instead of the default 32 3579 3580 ``counter=off`` 3581 Force a 'cut-down' L2TPv3 with no counter as in 3582 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3583 3584 ``pincounter=on`` 3585 Work around broken counter handling in peer. This may also help 3586 on networks which have packet reorder. 3587 3588 ``offset=offset`` 3589 Add an extra offset between header and data 3590 3591 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3592 the bridge br-lan on the remote Linux host 1.2.3.4: 3593 3594 .. parsed-literal:: 3595 3596 # Setup tunnel on linux host using raw ip as encapsulation 3597 # on 1.2.3.4 3598 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3599 encap udp udp_sport 16384 udp_dport 16384 3600 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3601 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3602 ifconfig vmtunnel0 mtu 1500 3603 ifconfig vmtunnel0 up 3604 brctl addif br-lan vmtunnel0 3605 3606 3607 # on 4.3.2.1 3608 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3609 3610 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3611 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp=on,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter=on 3612 3613``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3614 Configure VDE backend to connect to PORT n of a vde switch running 3615 on host and listening for incoming connections on socketpath. Use 3616 GROUP groupname and MODE octalmode to change default ownership and 3617 permissions for communication port. This option is only available if 3618 QEMU has been compiled with vde support enabled. 3619 3620 Example: 3621 3622 .. parsed-literal:: 3623 3624 # launch vde switch 3625 vde_switch -F -sock /tmp/myswitch 3626 # launch QEMU instance 3627 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3628 3629``-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]`` 3630 Configure AF_XDP backend to connect to a network interface 'name' 3631 using AF_XDP socket. A specific program attach mode for a default 3632 XDP program can be forced with 'mode', defaults to best-effort, 3633 where the likely most performant mode will be in use. Number of queues 3634 'n' should generally match the number or queues in the interface, 3635 defaults to 1. Traffic arriving on non-configured device queues will 3636 not be delivered to the network backend. 3637 3638 .. parsed-literal:: 3639 3640 # set number of queues to 4 3641 ethtool -L eth0 combined 4 3642 # launch QEMU instance 3643 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3644 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3645 3646 'start-queue' option can be specified if a particular range of queues 3647 [m, m + n] should be in use. For example, this is may be necessary in 3648 order to use certain NICs in native mode. Kernel allows the driver to 3649 create a separate set of XDP queues on top of regular ones, and only 3650 these queues can be used for AF_XDP sockets. NICs that work this way 3651 may also require an additional traffic redirection with ethtool to these 3652 special queues. 3653 3654 .. parsed-literal:: 3655 3656 # set number of queues to 1 3657 ethtool -L eth0 combined 1 3658 # redirect all the traffic to the second queue (id: 1) 3659 # note: drivers may require non-empty key/mask pair. 3660 ethtool -N eth0 flow-type ether \\ 3661 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3662 ethtool -N eth0 flow-type ether \\ 3663 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3664 # launch QEMU instance 3665 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3666 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3667 3668 XDP program can also be loaded externally. In this case 'inhibit' option 3669 should be set to 'on' and 'sock-fds' provided with file descriptors for 3670 already open but not bound XDP sockets already added to a socket map for 3671 corresponding queues. One socket per queue. 3672 3673 .. parsed-literal:: 3674 3675 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3676 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3677 3678``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3679 Establish a vhost-user netdev, backed by a chardev id. The chardev 3680 should be a unix domain socket backed one. The vhost-user uses a 3681 specifically defined protocol to pass vhost ioctl replacement 3682 messages to an application on the other end of the socket. On 3683 non-MSIX guests, the feature can be forced with vhostforce. Use 3684 'queues=n' to specify the number of queues to be created for 3685 multiqueue vhost-user. 3686 3687 Example: 3688 3689 :: 3690 3691 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3692 -numa node,memdev=mem \ 3693 -chardev socket,id=chr0,path=/path/to/socket \ 3694 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3695 -device virtio-net-pci,netdev=net0 3696 3697``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3698 Establish a vhost-vdpa netdev. 3699 3700 vDPA device is a device that uses a datapath which complies with 3701 the virtio specifications with a vendor specific control path. 3702 vDPA devices can be both physically located on the hardware or 3703 emulated by software. 3704 3705``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3706 Create a hub port on the emulated hub with ID hubid. 3707 3708 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3709 instead of a single netdev. Alternatively, you can also connect the 3710 hubport to another netdev with ID nd by using the ``netdev=nd`` 3711 option. 3712 3713``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3714 Legacy option to configure or create an on-board (or machine 3715 default) Network Interface Card(NIC) and connect it either to the 3716 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3717 If model is omitted, then the default NIC model associated with the 3718 machine type is used. Note that the default NIC model may change in 3719 future QEMU releases, so it is highly recommended to always specify 3720 a model. Optionally, the MAC address can be changed to mac, the 3721 device address set to addr (PCI cards only), and a name can be 3722 assigned for use in monitor commands. Optionally, for PCI cards, you 3723 can specify the number v of MSI-X vectors that the card should have; 3724 this option currently only affects virtio cards; set v = 0 to 3725 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3726 created. QEMU can emulate several different models of network card. 3727 Use ``-net nic,model=help`` for a list of available devices for your 3728 target. 3729 3730``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3731 Configure a host network backend (with the options corresponding to 3732 the same ``-netdev`` option) and connect it to the emulated hub 0 3733 (the default hub). Use name to specify the name of the hub port. 3734ERST 3735 3736DEFHEADING() 3737 3738DEFHEADING(Character device options:) 3739 3740DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3741 "-chardev help\n" 3742 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3743 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3744 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3745 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3746 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3747 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3748 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3749 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3750 " [,logfile=PATH][,logappend=on|off]\n" 3751 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3752 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3753 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3754 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3755 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3756 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3757#ifdef _WIN32 3758 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3759 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3760#else 3761 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3762 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3763#endif 3764#ifdef CONFIG_BRLAPI 3765 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3766#endif 3767#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3768 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3769 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3770#endif 3771#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3772 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3773#endif 3774#if defined(CONFIG_SPICE) 3775 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3776 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3777#endif 3778 , QEMU_ARCH_ALL 3779) 3780 3781SRST 3782The general form of a character device option is: 3783 3784``-chardev backend,id=id[,mux=on|off][,options]`` 3785 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3786 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3787 ``pty``, ``stdio``, ``braille``, ``parallel``, 3788 ``spicevmc``, ``spiceport``. The specific backend will determine the 3789 applicable options. 3790 3791 Use ``-chardev help`` to print all available chardev backend types. 3792 3793 All devices must have an id, which can be any string up to 127 3794 characters long. It is used to uniquely identify this device in 3795 other command line directives. 3796 3797 A character device may be used in multiplexing mode by multiple 3798 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3799 a "1:N" device, and here the "1" end is your specified chardev 3800 backend, and the "N" end is the various parts of QEMU that can talk 3801 to a chardev. If you create a chardev with ``id=myid`` and 3802 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3803 and you can then configure multiple front ends to use that chardev 3804 ID for their input/output. Up to four different front ends can be 3805 connected to a single multiplexed chardev. (Without multiplexing 3806 enabled, a chardev can only be used by a single front end.) For 3807 instance you could use this to allow a single stdio chardev to be 3808 used by two serial ports and the QEMU monitor: 3809 3810 :: 3811 3812 -chardev stdio,mux=on,id=char0 \ 3813 -mon chardev=char0,mode=readline \ 3814 -serial chardev:char0 \ 3815 -serial chardev:char0 3816 3817 You can have more than one multiplexer in a system configuration; 3818 for instance you could have a TCP port multiplexed between UART 0 3819 and UART 1, and stdio multiplexed between the QEMU monitor and a 3820 parallel port: 3821 3822 :: 3823 3824 -chardev stdio,mux=on,id=char0 \ 3825 -mon chardev=char0,mode=readline \ 3826 -parallel chardev:char0 \ 3827 -chardev tcp,...,mux=on,id=char1 \ 3828 -serial chardev:char1 \ 3829 -serial chardev:char1 3830 3831 When you're using a multiplexed character device, some escape 3832 sequences are interpreted in the input. See the chapter about 3833 :ref:`keys in the character backend multiplexer` in the 3834 System Emulation Users Guide for more details. 3835 3836 Note that some other command line options may implicitly create 3837 multiplexed character backends; for instance ``-serial mon:stdio`` 3838 creates a multiplexed stdio backend connected to the serial port and 3839 the QEMU monitor, and ``-nographic`` also multiplexes the console 3840 and the monitor to stdio. 3841 3842 There is currently no support for multiplexing in the other 3843 direction (where a single QEMU front end takes input and output from 3844 multiple chardevs). 3845 3846 Every backend supports the ``logfile`` option, which supplies the 3847 path to a file to record all data transmitted via the backend. The 3848 ``logappend`` option controls whether the log file will be truncated 3849 or appended to when opened. 3850 3851The available backends are: 3852 3853``-chardev null,id=id`` 3854 A void device. This device will not emit any data, and will drop any 3855 data it receives. The null backend does not take any options. 3856 3857``-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]`` 3858 Create a two-way stream socket, which can be either a TCP or a unix 3859 socket. A unix socket will be created if ``path`` is specified. 3860 Behaviour is undefined if TCP options are specified for a unix 3861 socket. 3862 3863 ``server=on|off`` specifies that the socket shall be a listening socket. 3864 3865 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3866 to connect to a listening socket. 3867 3868 ``telnet=on|off`` specifies that traffic on the socket should interpret 3869 telnet escape sequences. 3870 3871 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3872 communication. 3873 3874 ``reconnect`` sets the timeout for reconnecting on non-server 3875 sockets when the remote end goes away. qemu will delay this many 3876 seconds and then attempt to reconnect. Zero disables reconnecting, 3877 and is the default. 3878 3879 ``tls-creds`` requests enablement of the TLS protocol for 3880 encryption, and specifies the id of the TLS credentials to use for 3881 the handshake. The credentials must be previously created with the 3882 ``-object tls-creds`` argument. 3883 3884 ``tls-auth`` provides the ID of the QAuthZ authorization object 3885 against which the client's x509 distinguished name will be 3886 validated. This object is only resolved at time of use, so can be 3887 deleted and recreated on the fly while the chardev server is active. 3888 If missing, it will default to denying access. 3889 3890 TCP and unix socket options are given below: 3891 3892 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3893 ``host`` for a listening socket specifies the local address to 3894 be bound. For a connecting socket species the remote host to 3895 connect to. ``host`` is optional for listening sockets. If not 3896 specified it defaults to ``0.0.0.0``. 3897 3898 ``port`` for a listening socket specifies the local port to be 3899 bound. For a connecting socket specifies the port on the remote 3900 host to connect to. ``port`` can be given as either a port 3901 number or a service name. ``port`` is required. 3902 3903 ``to`` is only relevant to listening sockets. If it is 3904 specified, and ``port`` cannot be bound, QEMU will attempt to 3905 bind to subsequent ports up to and including ``to`` until it 3906 succeeds. ``to`` must be specified as a port number. 3907 3908 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3909 or IPv6 must be used. If neither is specified the socket may 3910 use either protocol. 3911 3912 ``nodelay=on|off`` disables the Nagle algorithm. 3913 3914 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3915 ``path`` specifies the local path of the unix socket. ``path`` 3916 is required. 3917 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3918 rather than the filesystem. Optional, defaults to false. 3919 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3920 rather than the full sun_path length. Optional, defaults to true. 3921 3922``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3923 Sends all traffic from the guest to a remote host over UDP. 3924 3925 ``host`` specifies the remote host to connect to. If not specified 3926 it defaults to ``localhost``. 3927 3928 ``port`` specifies the port on the remote host to connect to. 3929 ``port`` is required. 3930 3931 ``localaddr`` specifies the local address to bind to. If not 3932 specified it defaults to ``0.0.0.0``. 3933 3934 ``localport`` specifies the local port to bind to. If not specified 3935 any available local port will be used. 3936 3937 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3938 If neither is specified the device may use either protocol. 3939 3940``-chardev msmouse,id=id`` 3941 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3942 does not take any options. 3943 3944``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3945 Connect to a QEMU text console. ``vc`` may optionally be given a 3946 specific size. 3947 3948 ``width`` and ``height`` specify the width and height respectively 3949 of the console, in pixels. 3950 3951 ``cols`` and ``rows`` specify that the console be sized to fit a 3952 text console with the given dimensions. 3953 3954``-chardev ringbuf,id=id[,size=size]`` 3955 Create a ring buffer with fixed size ``size``. size must be a power 3956 of two and defaults to ``64K``. 3957 3958``-chardev file,id=id,path=path[,input-path=input-path]`` 3959 Log all traffic received from the guest to a file. 3960 3961 ``path`` specifies the path of the file to be opened. This file will 3962 be created if it does not already exist, and overwritten if it does. 3963 ``path`` is required. 3964 3965 If ``input-path`` is specified, this is the path of a second file 3966 which will be used for input. If ``input-path`` is not specified, 3967 no input will be available from the chardev. 3968 3969 Note that ``input-path`` is not supported on Windows hosts. 3970 3971``-chardev pipe,id=id,path=path`` 3972 Create a two-way connection to the guest. The behaviour differs 3973 slightly between Windows hosts and other hosts: 3974 3975 On Windows, a single duplex pipe will be created at 3976 ``\\.pipe\path``. 3977 3978 On other hosts, 2 pipes will be created called ``path.in`` and 3979 ``path.out``. Data written to ``path.in`` will be received by the 3980 guest. Data written by the guest can be read from ``path.out``. QEMU 3981 will not create these fifos, and requires them to be present. 3982 3983 ``path`` forms part of the pipe path as described above. ``path`` is 3984 required. 3985 3986``-chardev console,id=id`` 3987 Send traffic from the guest to QEMU's standard output. ``console`` 3988 does not take any options. 3989 3990 ``console`` is only available on Windows hosts. 3991 3992``-chardev serial,id=id,path=path`` 3993 Send traffic from the guest to a serial device on the host. 3994 3995 On Unix hosts serial will actually accept any tty device, not only 3996 serial lines. 3997 3998 ``path`` specifies the name of the serial device to open. 3999 4000``-chardev pty,id=id`` 4001 Create a new pseudo-terminal on the host and connect to it. ``pty`` 4002 does not take any options. 4003 4004 ``pty`` is not available on Windows hosts. 4005 4006``-chardev stdio,id=id[,signal=on|off]`` 4007 Connect to standard input and standard output of the QEMU process. 4008 4009 ``signal`` controls if signals are enabled on the terminal, that 4010 includes exiting QEMU with the key sequence Control-c. This option 4011 is enabled by default, use ``signal=off`` to disable it. 4012 4013``-chardev braille,id=id`` 4014 Connect to a local BrlAPI server. ``braille`` does not take any 4015 options. 4016 4017``-chardev parallel,id=id,path=path`` 4018 \ 4019 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 4020 hosts. 4021 4022 Connect to a local parallel port. 4023 4024 ``path`` specifies the path to the parallel port device. ``path`` is 4025 required. 4026 4027``-chardev spicevmc,id=id,debug=debug,name=name`` 4028 ``spicevmc`` is only available when spice support is built in. 4029 4030 ``debug`` debug level for spicevmc 4031 4032 ``name`` name of spice channel to connect to 4033 4034 Connect to a spice virtual machine channel, such as vdiport. 4035 4036``-chardev spiceport,id=id,debug=debug,name=name`` 4037 ``spiceport`` is only available when spice support is built in. 4038 4039 ``debug`` debug level for spicevmc 4040 4041 ``name`` name of spice port to connect to 4042 4043 Connect to a spice port, allowing a Spice client to handle the 4044 traffic identified by a name (preferably a fqdn). 4045ERST 4046 4047DEFHEADING() 4048 4049#ifdef CONFIG_TPM 4050DEFHEADING(TPM device options:) 4051 4052DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 4053 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 4054 " use path to provide path to a character device; default is /dev/tpm0\n" 4055 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 4056 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 4057 "-tpmdev emulator,id=id,chardev=dev\n" 4058 " configure the TPM device using chardev backend\n", 4059 QEMU_ARCH_ALL) 4060SRST 4061The general form of a TPM device option is: 4062 4063``-tpmdev backend,id=id[,options]`` 4064 The specific backend type will determine the applicable options. The 4065 ``-tpmdev`` option creates the TPM backend and requires a 4066 ``-device`` option that specifies the TPM frontend interface model. 4067 4068 Use ``-tpmdev help`` to print all available TPM backend types. 4069 4070The available backends are: 4071 4072``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 4073 (Linux-host only) Enable access to the host's TPM using the 4074 passthrough driver. 4075 4076 ``path`` specifies the path to the host's TPM device, i.e., on a 4077 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 4078 default ``/dev/tpm0`` is used. 4079 4080 ``cancel-path`` specifies the path to the host TPM device's sysfs 4081 entry allowing for cancellation of an ongoing TPM command. 4082 ``cancel-path`` is optional and by default QEMU will search for the 4083 sysfs entry to use. 4084 4085 Some notes about using the host's TPM with the passthrough driver: 4086 4087 The TPM device accessed by the passthrough driver must not be used 4088 by any other application on the host. 4089 4090 Since the host's firmware (BIOS/UEFI) has already initialized the 4091 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 4092 the TPM again and may therefore not show a TPM-specific menu that 4093 would otherwise allow the user to configure the TPM, e.g., allow the 4094 user to enable/disable or activate/deactivate the TPM. Further, if 4095 TPM ownership is released from within a VM then the host's TPM will 4096 get disabled and deactivated. To enable and activate the TPM again 4097 afterwards, the host has to be rebooted and the user is required to 4098 enter the firmware's menu to enable and activate the TPM. If the TPM 4099 is left disabled and/or deactivated most TPM commands will fail. 4100 4101 To create a passthrough TPM use the following two options: 4102 4103 :: 4104 4105 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 4106 4107 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 4108 ``tpmdev=tpm0`` in the device option. 4109 4110``-tpmdev emulator,id=id,chardev=dev`` 4111 (Linux-host only) Enable access to a TPM emulator using Unix domain 4112 socket based chardev backend. 4113 4114 ``chardev`` specifies the unique ID of a character device backend 4115 that provides connection to the software TPM server. 4116 4117 To create a TPM emulator backend device with chardev socket backend: 4118 4119 :: 4120 4121 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 4122ERST 4123 4124DEFHEADING() 4125 4126#endif 4127 4128DEFHEADING(Boot Image or Kernel specific:) 4129SRST 4130There are broadly 4 ways you can boot a system with QEMU. 4131 4132 - specify a firmware and let it control finding a kernel 4133 - specify a firmware and pass a hint to the kernel to boot 4134 - direct kernel image boot 4135 - manually load files into the guest's address space 4136 4137The third method is useful for quickly testing kernels but as there is 4138no firmware to pass configuration information to the kernel the 4139hardware must either be probeable, the kernel built for the exact 4140configuration or passed some configuration data (e.g. a DTB blob) 4141which tells the kernel what drivers it needs. This exact details are 4142often hardware specific. 4143 4144The final method is the most generic way of loading images into the 4145guest address space and used mostly for ``bare metal`` type 4146development where the reset vectors of the processor are taken into 4147account. 4148 4149ERST 4150 4151SRST 4152 4153For x86 machines and some other architectures ``-bios`` will generally 4154do the right thing with whatever it is given. For other machines the 4155more strict ``-pflash`` option needs an image that is sized for the 4156flash device for the given machine type. 4157 4158Please see the :ref:`system-targets-ref` section of the manual for 4159more detailed documentation. 4160 4161ERST 4162 4163DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4164 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4165SRST 4166``-bios file`` 4167 Set the filename for the BIOS. 4168ERST 4169 4170DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 4171 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 4172SRST 4173``-pflash file`` 4174 Use file as a parallel flash image. 4175ERST 4176 4177SRST 4178 4179The kernel options were designed to work with Linux kernels although 4180other things (like hypervisors) can be packaged up as a kernel 4181executable image. The exact format of a executable image is usually 4182architecture specific. 4183 4184The way in which the kernel is started (what address it is loaded at, 4185what if any information is passed to it via CPU registers, the state 4186of the hardware when it is started, and so on) is also architecture 4187specific. Typically it follows the specification laid down by the 4188Linux kernel for how kernels for that architecture must be started. 4189 4190ERST 4191 4192DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 4193 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 4194SRST 4195``-kernel bzImage`` 4196 Use bzImage as kernel image. The kernel can be either a Linux kernel 4197 or in multiboot format. 4198ERST 4199 4200DEF("append", HAS_ARG, QEMU_OPTION_append, \ 4201 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 4202SRST 4203``-append cmdline`` 4204 Use cmdline as kernel command line 4205ERST 4206 4207DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4208 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4209SRST(initrd) 4210 4211``-initrd file`` 4212 Use file as initial ram disk. 4213 4214``-initrd "file1 arg=foo,file2"`` 4215 This syntax is only available with multiboot. 4216 4217 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4218 first module. Commas can be provided in module parameters by doubling 4219 them on the command line to escape them: 4220 4221``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4222 Multiboot only. Use bzImage as the first module with 4223 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4224 and initrd.img as the second module. 4225 4226ERST 4227 4228DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4229 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4230SRST 4231``-dtb file`` 4232 Use file as a device tree binary (dtb) image and pass it to the 4233 kernel on boot. 4234ERST 4235 4236SRST 4237 4238Finally you can also manually load images directly into the address 4239space of the guest. This is most useful for developers who already 4240know the layout of their guest and take care to ensure something sane 4241will happen when the reset vector executes. 4242 4243The generic loader can be invoked by using the loader device: 4244 4245``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4246 4247there is also the guest loader which operates in a similar way but 4248tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4249the guest image is: 4250 4251``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4252 4253ERST 4254 4255DEFHEADING() 4256 4257DEFHEADING(Debug/Expert options:) 4258 4259DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4260 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4261 " Policy for handling deprecated management interfaces\n" 4262 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4263 " Policy for handling unstable management interfaces\n", 4264 QEMU_ARCH_ALL) 4265SRST 4266``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4267 Set policy for handling deprecated management interfaces (experimental): 4268 4269 ``deprecated-input=accept`` (default) 4270 Accept deprecated commands and arguments 4271 ``deprecated-input=reject`` 4272 Reject deprecated commands and arguments 4273 ``deprecated-input=crash`` 4274 Crash on deprecated commands and arguments 4275 ``deprecated-output=accept`` (default) 4276 Emit deprecated command results and events 4277 ``deprecated-output=hide`` 4278 Suppress deprecated command results and events 4279 4280 Limitation: covers only syntactic aspects of QMP. 4281 4282``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4283 Set policy for handling unstable management interfaces (experimental): 4284 4285 ``unstable-input=accept`` (default) 4286 Accept unstable commands and arguments 4287 ``unstable-input=reject`` 4288 Reject unstable commands and arguments 4289 ``unstable-input=crash`` 4290 Crash on unstable commands and arguments 4291 ``unstable-output=accept`` (default) 4292 Emit unstable command results and events 4293 ``unstable-output=hide`` 4294 Suppress unstable command results and events 4295 4296 Limitation: covers only syntactic aspects of QMP. 4297ERST 4298 4299DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4300 "-fw_cfg [name=]<name>,file=<file>\n" 4301 " add named fw_cfg entry with contents from file\n" 4302 "-fw_cfg [name=]<name>,string=<str>\n" 4303 " add named fw_cfg entry with contents from string\n", 4304 QEMU_ARCH_ALL) 4305SRST 4306``-fw_cfg [name=]name,file=file`` 4307 Add named fw\_cfg entry with contents from file file. 4308 If the filename contains comma, you must double it (for instance, 4309 "file=my,,file" to use file "my,file"). 4310 4311``-fw_cfg [name=]name,string=str`` 4312 Add named fw\_cfg entry with contents from string str. 4313 If the string contains comma, you must double it (for instance, 4314 "string=my,,string" to use file "my,string"). 4315 4316 The terminating NUL character of the contents of str will not be 4317 included as part of the fw\_cfg item data. To insert contents with 4318 embedded NUL characters, you have to use the file parameter. 4319 4320 The fw\_cfg entries are passed by QEMU through to the guest. 4321 4322 Example: 4323 4324 :: 4325 4326 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4327 4328 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4329 from ./my\_blob.bin. 4330ERST 4331 4332DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4333 "-serial dev redirect the serial port to char device 'dev'\n", 4334 QEMU_ARCH_ALL) 4335SRST 4336``-serial dev`` 4337 Redirect the virtual serial port to host character device dev. The 4338 default device is ``vc`` in graphical mode and ``stdio`` in non 4339 graphical mode. 4340 4341 This option can be used several times to simulate multiple serial 4342 ports. 4343 4344 You can use ``-serial none`` to suppress the creation of default 4345 serial devices. 4346 4347 Available character devices are: 4348 4349 ``vc[:WxH]`` 4350 Virtual console. Optionally, a width and height can be given in 4351 pixel with 4352 4353 :: 4354 4355 vc:800x600 4356 4357 It is also possible to specify width or height in characters: 4358 4359 :: 4360 4361 vc:80Cx24C 4362 4363 ``pty`` 4364 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4365 4366 ``none`` 4367 No device is allocated. Note that for machine types which 4368 emulate systems where a serial device is always present in 4369 real hardware, this may be equivalent to the ``null`` option, 4370 in that the serial device is still present but all output 4371 is discarded. For boards where the number of serial ports is 4372 truly variable, this suppresses the creation of the device. 4373 4374 ``null`` 4375 A guest will see the UART or serial device as present in the 4376 machine, but all output is discarded, and there is no input. 4377 Conceptually equivalent to redirecting the output to ``/dev/null``. 4378 4379 ``chardev:id`` 4380 Use a named character device defined with the ``-chardev`` 4381 option. 4382 4383 ``/dev/XXX`` 4384 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4385 port parameters are set according to the emulated ones. 4386 4387 ``/dev/parportN`` 4388 [Linux only, parallel port only] Use host parallel port N. 4389 Currently SPP and EPP parallel port features can be used. 4390 4391 ``file:filename`` 4392 Write output to filename. No character can be read. 4393 4394 ``stdio`` 4395 [Unix only] standard input/output 4396 4397 ``pipe:filename`` 4398 name pipe filename 4399 4400 ``COMn`` 4401 [Windows only] Use host serial port n 4402 4403 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4404 This implements UDP Net Console. When remote\_host or src\_ip 4405 are not specified they default to ``0.0.0.0``. When not using a 4406 specified src\_port a random port is automatically chosen. 4407 4408 If you just want a simple readonly console you can use 4409 ``netcat`` or ``nc``, by starting QEMU with: 4410 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4411 QEMU writes something to that port it will appear in the 4412 netconsole session. 4413 4414 If you plan to send characters back via netconsole or you want 4415 to stop and start QEMU a lot of times, you should have QEMU use 4416 the same source port each time by using something like ``-serial 4417 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4418 version of netcat which can listen to a TCP port and send and 4419 receive characters via udp. If you have a patched version of 4420 netcat which activates telnet remote echo and single char 4421 transfer, then you can use the following options to set up a 4422 netcat redirector to allow telnet on port 5555 to access the 4423 QEMU port. 4424 4425 ``QEMU Options:`` 4426 -serial udp::4555@:4556 4427 4428 ``netcat options:`` 4429 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4430 4431 ``telnet options:`` 4432 localhost 5555 4433 4434 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4435 The TCP Net Console has two modes of operation. It can send the 4436 serial I/O to a location or wait for a connection from a 4437 location. By default the TCP Net Console is sent to host at the 4438 port. If you use the ``server=on`` option QEMU will wait for a client 4439 socket application to connect to the port before continuing, 4440 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4441 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4442 option only applies if ``server=no`` is set, if the connection goes 4443 down it will attempt to reconnect at the given interval. If host 4444 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4445 time is accepted. You can use ``telnet=on`` to connect to the 4446 corresponding character device. 4447 4448 ``Example to send tcp console to 192.168.0.2 port 4444`` 4449 -serial tcp:192.168.0.2:4444 4450 4451 ``Example to listen and wait on port 4444 for connection`` 4452 -serial tcp::4444,server=on 4453 4454 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4455 -serial tcp:192.168.0.100:4444,server=on,wait=off 4456 4457 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4458 The telnet protocol is used instead of raw tcp sockets. The 4459 options work the same as if you had specified ``-serial tcp``. 4460 The difference is that the port acts like a telnet server or 4461 client using telnet option negotiation. This will also allow you 4462 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4463 supports sending the break sequence. Typically in unix telnet 4464 you do it with Control-] and then type "send break" followed by 4465 pressing the enter key. 4466 4467 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4468 The WebSocket protocol is used instead of raw tcp socket. The 4469 port acts as a WebSocket server. Client mode is not supported. 4470 4471 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4472 A unix domain socket is used instead of a tcp socket. The option 4473 works the same as if you had specified ``-serial tcp`` except 4474 the unix domain socket path is used for connections. 4475 4476 ``mon:dev_string`` 4477 This is a special option to allow the monitor to be multiplexed 4478 onto another serial port. The monitor is accessed with key 4479 sequence of Control-a and then pressing c. dev\_string should be 4480 any one of the serial devices specified above. An example to 4481 multiplex the monitor onto a telnet server listening on port 4482 4444 would be: 4483 4484 ``-serial mon:telnet::4444,server=on,wait=off`` 4485 4486 When the monitor is multiplexed to stdio in this way, Ctrl+C 4487 will not terminate QEMU any more but will be passed to the guest 4488 instead. 4489 4490 ``braille`` 4491 Braille device. This will use BrlAPI to display the braille 4492 output on a real or fake device. 4493 4494 ``msmouse`` 4495 Three button serial mouse. Configure the guest to use Microsoft 4496 protocol. 4497ERST 4498 4499DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4500 "-parallel dev redirect the parallel port to char device 'dev'\n", 4501 QEMU_ARCH_ALL) 4502SRST 4503``-parallel dev`` 4504 Redirect the virtual parallel port to host device dev (same devices 4505 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4506 to use hardware devices connected on the corresponding host parallel 4507 port. 4508 4509 This option can be used several times to simulate up to 3 parallel 4510 ports. 4511 4512 Use ``-parallel none`` to disable all parallel ports. 4513ERST 4514 4515DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4516 "-monitor dev redirect the monitor to char device 'dev'\n", 4517 QEMU_ARCH_ALL) 4518SRST 4519``-monitor dev`` 4520 Redirect the monitor to host device dev (same devices as the serial 4521 port). The default device is ``vc`` in graphical mode and ``stdio`` 4522 in non graphical mode. Use ``-monitor none`` to disable the default 4523 monitor. 4524ERST 4525DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4526 "-qmp dev like -monitor but opens in 'control' mode\n", 4527 QEMU_ARCH_ALL) 4528SRST 4529``-qmp dev`` 4530 Like ``-monitor`` but opens in 'control' mode. For example, to make 4531 QMP available on localhost port 4444:: 4532 4533 -qmp tcp:localhost:4444,server=on,wait=off 4534 4535 Not all options are configurable via this syntax; for maximum 4536 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4537 4538ERST 4539DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4540 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4541 QEMU_ARCH_ALL) 4542SRST 4543``-qmp-pretty dev`` 4544 Like ``-qmp`` but uses pretty JSON formatting. 4545ERST 4546 4547DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4548 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4549SRST 4550``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4551 Set up a monitor connected to the chardev ``name``. 4552 QEMU supports two monitors: the Human Monitor Protocol 4553 (HMP; for human interaction), and the QEMU Monitor Protocol 4554 (QMP; a JSON RPC-style protocol). 4555 The default is HMP; ``mode=control`` selects QMP instead. 4556 ``pretty`` is only valid when ``mode=control``, 4557 turning on JSON pretty printing to ease 4558 human reading and debugging. 4559 4560 For example:: 4561 4562 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4563 -mon chardev=mon1,mode=control,pretty=on 4564 4565 enables the QMP monitor on localhost port 4444 with pretty-printing. 4566ERST 4567 4568DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4569 "-debugcon dev redirect the debug console to char device 'dev'\n", 4570 QEMU_ARCH_ALL) 4571SRST 4572``-debugcon dev`` 4573 Redirect the debug console to host device dev (same devices as the 4574 serial port). The debug console is an I/O port which is typically 4575 port 0xe9; writing to that I/O port sends output to this device. The 4576 default device is ``vc`` in graphical mode and ``stdio`` in non 4577 graphical mode. 4578ERST 4579 4580DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4581 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4582SRST 4583``-pidfile file`` 4584 Store the QEMU process PID in file. It is useful if you launch QEMU 4585 from a script. 4586ERST 4587 4588DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4589 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4590 QEMU_ARCH_ALL) 4591SRST 4592``--preconfig`` 4593 Pause QEMU for interactive configuration before the machine is 4594 created, which allows querying and configuring properties that will 4595 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4596 exit the preconfig state and move to the next state (i.e. run guest 4597 if -S isn't used or pause the second time if -S is used). This 4598 option is experimental. 4599ERST 4600 4601DEF("S", 0, QEMU_OPTION_S, \ 4602 "-S freeze CPU at startup (use 'c' to start execution)\n", 4603 QEMU_ARCH_ALL) 4604SRST 4605``-S`` 4606 Do not start CPU at startup (you must type 'c' in the monitor). 4607ERST 4608 4609DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4610 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4611 " run qemu with overcommit hints\n" 4612 " mem-lock=on|off controls memory lock support (default: off)\n" 4613 " cpu-pm=on|off controls cpu power management (default: off)\n", 4614 QEMU_ARCH_ALL) 4615SRST 4616``-overcommit mem-lock=on|off`` 4617 \ 4618``-overcommit cpu-pm=on|off`` 4619 Run qemu with hints about host resource overcommit. The default is 4620 to assume that host overcommits all resources. 4621 4622 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4623 (disabled by default). This works when host memory is not 4624 overcommitted and reduces the worst-case latency for guest. 4625 4626 Guest ability to manage power state of host cpus (increasing latency 4627 for other processes on the same host cpu, but decreasing latency for 4628 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4629 works best when host CPU is not overcommitted. When used, host 4630 estimates of CPU cycle and power utilization will be incorrect, not 4631 taking into account guest idle time. 4632ERST 4633 4634DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4635 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4636 " the guest without waiting for gdb to connect; use -S too\n" 4637 " if you want it to not start execution.)\n", 4638 QEMU_ARCH_ALL) 4639SRST 4640``-gdb dev`` 4641 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4642 in the System Emulation Users Guide). Note that this option does not pause QEMU 4643 execution -- if you want QEMU to not start the guest until you 4644 connect with gdb and issue a ``continue`` command, you will need to 4645 also pass the ``-S`` option to QEMU. 4646 4647 The most usual configuration is to listen on a local TCP socket:: 4648 4649 -gdb tcp::3117 4650 4651 but you can specify other backends; UDP, pseudo TTY, or even stdio 4652 are all reasonable use cases. For example, a stdio connection 4653 allows you to start QEMU from within gdb and establish the 4654 connection via a pipe: 4655 4656 .. parsed-literal:: 4657 4658 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4659ERST 4660 4661DEF("s", 0, QEMU_OPTION_s, \ 4662 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4663 QEMU_ARCH_ALL) 4664SRST 4665``-s`` 4666 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4667 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4668ERST 4669 4670DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4671 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4672 QEMU_ARCH_ALL) 4673SRST 4674``-d item1[,...]`` 4675 Enable logging of specified items. Use '-d help' for a list of log 4676 items. 4677ERST 4678 4679DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4680 "-D logfile output log to logfile (default stderr)\n", 4681 QEMU_ARCH_ALL) 4682SRST 4683``-D logfile`` 4684 Output log in logfile instead of to stderr 4685ERST 4686 4687DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4688 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4689 QEMU_ARCH_ALL) 4690SRST 4691``-dfilter range1[,...]`` 4692 Filter debug output to that relevant to a range of target addresses. 4693 The filter spec can be either start+size, start-size or start..end 4694 where start end and size are the addresses and sizes required. For 4695 example: 4696 4697 :: 4698 4699 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4700 4701 Will dump output for any code in the 0x1000 sized block starting at 4702 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4703 another 0x1000 sized block starting at 0xffffffc00005f000. 4704ERST 4705 4706DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4707 "-seed number seed the pseudo-random number generator\n", 4708 QEMU_ARCH_ALL) 4709SRST 4710``-seed number`` 4711 Force the guest to use a deterministic pseudo-random number 4712 generator, seeded with number. This does not affect crypto routines 4713 within the host. 4714ERST 4715 4716DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4717 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4718 QEMU_ARCH_ALL) 4719SRST 4720``-L path`` 4721 Set the directory for the BIOS, VGA BIOS and keymaps. 4722 4723 To list all the data directories, use ``-L help``. 4724ERST 4725 4726DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4727 "-enable-kvm enable KVM full virtualization support\n", 4728 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4729 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4730SRST 4731``-enable-kvm`` 4732 Enable KVM full virtualization support. This option is only 4733 available if KVM support is enabled when compiling. 4734ERST 4735 4736DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4737 "-xen-domid id specify xen guest domain id\n", 4738 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4739DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4740 "-xen-attach attach to existing xen domain\n" 4741 " libxl will use this when starting QEMU\n", 4742 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4743DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4744 "-xen-domid-restrict restrict set of available xen operations\n" 4745 " to specified domain id. (Does not affect\n" 4746 " xenpv machine type).\n", 4747 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4748SRST 4749``-xen-domid id`` 4750 Specify xen guest domain id (XEN only). 4751 4752``-xen-attach`` 4753 Attach to existing xen domain. libxl will use this when starting 4754 QEMU (XEN only). Restrict set of available xen operations to 4755 specified domain id (XEN only). 4756ERST 4757 4758DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4759 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4760SRST 4761``-no-reboot`` 4762 Exit instead of rebooting. 4763ERST 4764 4765DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4766 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4767SRST 4768``-no-shutdown`` 4769 Don't exit QEMU on guest shutdown, but instead only stop the 4770 emulation. This allows for instance switching to monitor to commit 4771 changes to the disk image. 4772ERST 4773 4774DEF("action", HAS_ARG, QEMU_OPTION_action, 4775 "-action reboot=reset|shutdown\n" 4776 " action when guest reboots [default=reset]\n" 4777 "-action shutdown=poweroff|pause\n" 4778 " action when guest shuts down [default=poweroff]\n" 4779 "-action panic=pause|shutdown|exit-failure|none\n" 4780 " action when guest panics [default=shutdown]\n" 4781 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4782 " action when watchdog fires [default=reset]\n", 4783 QEMU_ARCH_ALL) 4784SRST 4785``-action event=action`` 4786 The action parameter serves to modify QEMU's default behavior when 4787 certain guest events occur. It provides a generic method for specifying the 4788 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4789 parameters. 4790 4791 Examples: 4792 4793 ``-action panic=none`` 4794 ``-action reboot=shutdown,shutdown=pause`` 4795 ``-device i6300esb -action watchdog=pause`` 4796 4797ERST 4798 4799DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4800 "-loadvm [tag|id]\n" \ 4801 " start right away with a saved state (loadvm in monitor)\n", 4802 QEMU_ARCH_ALL) 4803SRST 4804``-loadvm file`` 4805 Start right away with a saved state (``loadvm`` in monitor) 4806ERST 4807 4808#ifndef _WIN32 4809DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4810 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4811#endif 4812SRST 4813``-daemonize`` 4814 Daemonize the QEMU process after initialization. QEMU will not 4815 detach from standard IO until it is ready to receive connections on 4816 any of its devices. This option is a useful way for external 4817 programs to launch QEMU without having to cope with initialization 4818 race conditions. 4819ERST 4820 4821DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4822 "-option-rom rom load a file, rom, into the option ROM space\n", 4823 QEMU_ARCH_ALL) 4824SRST 4825``-option-rom file`` 4826 Load the contents of file as an option ROM. This option is useful to 4827 load things like EtherBoot. 4828ERST 4829 4830DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4831 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4832 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4833 QEMU_ARCH_ALL) 4834 4835SRST 4836``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4837 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4838 the current UTC or local time, respectively. ``localtime`` is 4839 required for correct date in MS-DOS or Windows. To start at a 4840 specific point in time, provide datetime in the format 4841 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4842 4843 By default the RTC is driven by the host system time. This allows 4844 using of the RTC as accurate reference clock inside the guest, 4845 specifically if the host time is smoothly following an accurate 4846 external reference clock, e.g. via NTP. If you want to isolate the 4847 guest time from the host, you can set ``clock`` to ``rt`` instead, 4848 which provides a host monotonic clock if host support it. To even 4849 prevent the RTC from progressing during suspension, you can set 4850 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4851 recommended especially in icount mode in order to preserve 4852 determinism; however, note that in icount mode the speed of the 4853 virtual clock is variable and can in general differ from the host 4854 clock. 4855 4856 Enable ``driftfix`` (i386 targets only) if you experience time drift 4857 problems, specifically with Windows' ACPI HAL. This option will try 4858 to figure out how many timer interrupts were not processed by the 4859 Windows guest and will re-inject them. 4860ERST 4861 4862DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4863 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4864 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4865 " instruction, enable aligning the host and virtual clocks\n" \ 4866 " or disable real time cpu sleeping, and optionally enable\n" \ 4867 " record-and-replay mode\n", QEMU_ARCH_ALL) 4868SRST 4869``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4870 Enable virtual instruction counter. The virtual cpu will execute one 4871 instruction every 2^N ns of virtual time. If ``auto`` is specified 4872 then the virtual cpu speed will be automatically adjusted to keep 4873 virtual time within a few seconds of real time. 4874 4875 Note that while this option can give deterministic behavior, it does 4876 not provide cycle accurate emulation. Modern CPUs contain 4877 superscalar out of order cores with complex cache hierarchies. The 4878 number of instructions executed often has little or no correlation 4879 with actual performance. 4880 4881 When the virtual cpu is sleeping, the virtual time will advance at 4882 default speed unless ``sleep=on`` is specified. With 4883 ``sleep=on``, the virtual time will jump to the next timer 4884 deadline instantly whenever the virtual cpu goes to sleep mode and 4885 will not advance if no timer is enabled. This behavior gives 4886 deterministic execution times from the guest point of view. 4887 The default if icount is enabled is ``sleep=off``. 4888 ``sleep=on`` cannot be used together with either ``shift=auto`` 4889 or ``align=on``. 4890 4891 ``align=on`` will activate the delay algorithm which will try to 4892 synchronise the host clock and the virtual clock. The goal is to 4893 have a guest running at the real frequency imposed by the shift 4894 option. Whenever the guest clock is behind the host clock and if 4895 ``align=on`` is specified then we print a message to the user to 4896 inform about the delay. Currently this option does not work when 4897 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4898 shift values for which the guest clock runs ahead of the host clock. 4899 Typically this happens when the shift value is high (how high 4900 depends on the host machine). The default if icount is enabled 4901 is ``align=off``. 4902 4903 When the ``rr`` option is specified deterministic record/replay is 4904 enabled. The ``rrfile=`` option must also be provided to 4905 specify the path to the replay log. In record mode data is written 4906 to this file, and in replay mode it is read back. 4907 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4908 name. In record mode, a new VM snapshot with the given name is created 4909 at the start of execution recording. In replay mode this option 4910 specifies the snapshot name used to load the initial VM state. 4911ERST 4912 4913DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4914 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4915 " action when watchdog fires [default=reset]\n", 4916 QEMU_ARCH_ALL) 4917SRST 4918``-watchdog-action action`` 4919 The action controls what QEMU will do when the watchdog timer 4920 expires. The default is ``reset`` (forcefully reset the guest). 4921 Other possible actions are: ``shutdown`` (attempt to gracefully 4922 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4923 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4924 guest), ``debug`` (print a debug message and continue), or ``none`` 4925 (do nothing). 4926 4927 Note that the ``shutdown`` action requires that the guest responds 4928 to ACPI signals, which it may not be able to do in the sort of 4929 situations where the watchdog would have expired, and thus 4930 ``-watchdog-action shutdown`` is not recommended for production use. 4931 4932 Examples: 4933 4934 ``-device i6300esb -watchdog-action pause`` 4935 4936ERST 4937 4938DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4939 "-echr chr set terminal escape character instead of ctrl-a\n", 4940 QEMU_ARCH_ALL) 4941SRST 4942``-echr numeric_ascii_value`` 4943 Change the escape character used for switching to the monitor when 4944 using monitor and serial sharing. The default is ``0x01`` when using 4945 the ``-nographic`` option. ``0x01`` is equal to pressing 4946 ``Control-a``. You can select a different character from the ascii 4947 control keys where 1 through 26 map to Control-a through Control-z. 4948 For instance you could use the either of the following to change the 4949 escape character to Control-t. 4950 4951 ``-echr 0x14``; \ ``-echr 20`` 4952 4953ERST 4954 4955DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4956 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4957 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4958 "-incoming unix:socketpath\n" \ 4959 " prepare for incoming migration, listen on\n" \ 4960 " specified protocol and socket address\n" \ 4961 "-incoming fd:fd\n" \ 4962 "-incoming file:filename[,offset=offset]\n" \ 4963 "-incoming exec:cmdline\n" \ 4964 " accept incoming migration on given file descriptor\n" \ 4965 " or from given external command\n" \ 4966 "-incoming defer\n" \ 4967 " wait for the URI to be specified via migrate_incoming\n", 4968 QEMU_ARCH_ALL) 4969SRST 4970``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4971 \ 4972``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4973 Prepare for incoming migration, listen on a given tcp port. 4974 4975``-incoming unix:socketpath`` 4976 Prepare for incoming migration, listen on a given unix socket. 4977 4978``-incoming fd:fd`` 4979 Accept incoming migration from a given file descriptor. 4980 4981``-incoming file:filename[,offset=offset]`` 4982 Accept incoming migration from a given file starting at offset. 4983 offset allows the common size suffixes, or a 0x prefix, but not both. 4984 4985``-incoming exec:cmdline`` 4986 Accept incoming migration as an output from specified external 4987 command. 4988 4989``-incoming defer`` 4990 Wait for the URI to be specified via migrate\_incoming. The monitor 4991 can be used to change settings (such as migration parameters) prior 4992 to issuing the migrate\_incoming to allow the migration to begin. 4993ERST 4994 4995DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4996 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4997SRST 4998``-only-migratable`` 4999 Only allow migratable devices. Devices will not be allowed to enter 5000 an unmigratable state. 5001ERST 5002 5003DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 5004 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 5005SRST 5006``-nodefaults`` 5007 Don't create default devices. Normally, QEMU sets the default 5008 devices like serial port, parallel port, virtual console, monitor 5009 device, VGA adapter, floppy and CD-ROM drive and others. The 5010 ``-nodefaults`` option will disable all those default devices. 5011ERST 5012 5013#ifndef _WIN32 5014DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 5015 "-runas user change to user id user just before starting the VM\n" \ 5016 " user can be numeric uid:gid instead\n", 5017 QEMU_ARCH_ALL) 5018#endif 5019SRST 5020``-runas user`` 5021 Immediately before starting guest execution, drop root privileges, 5022 switching to the specified user. This option is deprecated, use 5023 ``-run-with user=...`` instead. 5024ERST 5025 5026DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 5027 "-prom-env variable=value\n" 5028 " set OpenBIOS nvram variables\n", 5029 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 5030SRST 5031``-prom-env variable=value`` 5032 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 5033 5034 :: 5035 5036 qemu-system-sparc -prom-env 'auto-boot?=false' \ 5037 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 5038 5039 :: 5040 5041 qemu-system-ppc -prom-env 'auto-boot?=false' \ 5042 -prom-env 'boot-device=hd:2,\yaboot' \ 5043 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 5044ERST 5045DEF("semihosting", 0, QEMU_OPTION_semihosting, 5046 "-semihosting semihosting mode\n", 5047 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 5048 QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 5049SRST 5050``-semihosting`` 5051 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, RISC-V only). 5052 5053 .. warning:: 5054 Note that this allows guest direct access to the host filesystem, so 5055 should only be used with a trusted guest OS. 5056 5057 See the -semihosting-config option documentation for further 5058 information about the facilities this enables. 5059ERST 5060DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 5061 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 5062 " semihosting configuration\n", 5063QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 5064QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 5065SRST 5066``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 5067 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, RISC-V 5068 only). 5069 5070 .. warning:: 5071 Note that this allows guest direct access to the host filesystem, so 5072 should only be used with a trusted guest OS. 5073 5074 ``target=native|gdb|auto`` 5075 Defines where the semihosting calls will be addressed, to QEMU 5076 (``native``) or to GDB (``gdb``). The default is ``auto``, which 5077 means ``gdb`` during debug sessions and ``native`` otherwise. 5078 5079 ``chardev=str1`` 5080 Send the output to a chardev backend output for native or auto 5081 output when not in gdb 5082 5083 ``userspace=on|off`` 5084 Allows code running in guest userspace to access the semihosting 5085 interface. The default is that only privileged guest code can 5086 make semihosting calls. Note that setting ``userspace=on`` should 5087 only be used if all guest code is trusted (for example, in 5088 bare-metal test case code). 5089 5090 ``arg=str1,arg=str2,...`` 5091 Allows the user to pass input arguments, and can be used 5092 multiple times to build up a list. The old-style 5093 ``-kernel``/``-append`` method of passing a command line is 5094 still supported for backward compatibility. If both the 5095 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 5096 specified, the former is passed to semihosting as it always 5097 takes precedence. 5098ERST 5099DEF("old-param", 0, QEMU_OPTION_old_param, 5100 "-old-param old param mode\n", QEMU_ARCH_ARM) 5101SRST 5102``-old-param`` 5103 Old param mode (ARM only). 5104ERST 5105 5106DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 5107 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 5108 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 5109 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 5110 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 5111 " by the kernel, but typically no longer used by modern\n" \ 5112 " C library implementations.\n" \ 5113 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 5114 " to elevate privileges using set*uid|gid system calls.\n" \ 5115 " The value 'children' will deny set*uid|gid system calls for\n" \ 5116 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 5117 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 5118 " blocking *fork and execve\n" \ 5119 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 5120 QEMU_ARCH_ALL) 5121SRST 5122``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 5123 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 5124 filtering and 'off' will disable it. The default is 'off'. 5125 5126 ``obsolete=string`` 5127 Enable Obsolete system calls 5128 5129 ``elevateprivileges=string`` 5130 Disable set\*uid\|gid system calls 5131 5132 ``spawn=string`` 5133 Disable \*fork and execve 5134 5135 ``resourcecontrol=string`` 5136 Disable process affinity and schedular priority 5137ERST 5138 5139DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 5140 "-readconfig <file>\n" 5141 " read config file\n", QEMU_ARCH_ALL) 5142SRST 5143``-readconfig file`` 5144 Read device configuration from file. This approach is useful when 5145 you want to spawn QEMU process with many command line options but 5146 you don't want to exceed the command line character limit. 5147ERST 5148 5149DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 5150 "-no-user-config\n" 5151 " do not load default user-provided config files at startup\n", 5152 QEMU_ARCH_ALL) 5153SRST 5154``-no-user-config`` 5155 The ``-no-user-config`` option makes QEMU not load any of the 5156 user-provided config files on sysconfdir. 5157ERST 5158 5159DEF("trace", HAS_ARG, QEMU_OPTION_trace, 5160 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 5161 " specify tracing options\n", 5162 QEMU_ARCH_ALL) 5163SRST 5164``-trace [[enable=]pattern][,events=file][,file=file]`` 5165 .. include:: ../qemu-option-trace.rst.inc 5166 5167ERST 5168DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 5169 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 5170 " load a plugin\n", 5171 QEMU_ARCH_ALL) 5172SRST 5173``-plugin file=file[,argname=argvalue]`` 5174 Load a plugin. 5175 5176 ``file=file`` 5177 Load the given plugin from a shared library file. 5178 5179 ``argname=argvalue`` 5180 Argument passed to the plugin. (Can be given multiple times.) 5181ERST 5182 5183HXCOMM Internal use 5184DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 5185DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 5186 5187#ifdef CONFIG_POSIX 5188DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 5189 "-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]\n" 5190 " Set miscellaneous QEMU process lifecycle options:\n" 5191 " async-teardown=on enables asynchronous teardown (Linux only)\n" 5192 " chroot=dir chroot to dir just before starting the VM\n" 5193 " user=username switch to the specified user before starting the VM\n" 5194 " user=uid:gid ditto, but use specified user-ID and group-ID instead\n", 5195 QEMU_ARCH_ALL) 5196SRST 5197``-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]`` 5198 Set QEMU process lifecycle options. 5199 5200 ``async-teardown=on`` enables asynchronous teardown. A new process called 5201 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5202 space with the main QEMU process, using clone. It will wait for the 5203 main QEMU process to terminate completely, and then exit. This allows 5204 QEMU to terminate very quickly even if the guest was huge, leaving the 5205 teardown of the address space to the cleanup process. Since the cleanup 5206 process shares the same cgroups as the main QEMU process, accounting is 5207 performed correctly. This only works if the cleanup process is not 5208 forcefully killed with SIGKILL before the main QEMU process has 5209 terminated completely. 5210 5211 ``chroot=dir`` can be used for doing a chroot to the specified directory 5212 immediately before starting the guest execution. This is especially useful 5213 in combination with -runas. 5214 5215 ``user=username`` or ``user=uid:gid`` can be used to drop root privileges 5216 before starting guest execution. QEMU will use the ``setuid`` and ``setgid`` 5217 system calls to switch to the specified identity. Note that the 5218 ``user=username`` syntax will also apply the full set of supplementary 5219 groups for the user, whereas the ``user=uid:gid`` will use only the 5220 ``gid`` group. 5221ERST 5222#endif 5223 5224DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5225 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5226 " control error message format\n" 5227 " timestamp=on enables timestamps (default: off)\n" 5228 " guest-name=on enables guest name prefix but only if\n" 5229 " -name guest option is set (default: off)\n", 5230 QEMU_ARCH_ALL) 5231SRST 5232``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5233 Control error message format. 5234 5235 ``timestamp=on|off`` 5236 Prefix messages with a timestamp. Default is off. 5237 5238 ``guest-name=on|off`` 5239 Prefix messages with guest name but only if -name guest option is set 5240 otherwise the option is ignored. Default is off. 5241ERST 5242 5243DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5244 "-dump-vmstate <file>\n" 5245 " Output vmstate information in JSON format to file.\n" 5246 " Use the scripts/vmstate-static-checker.py file to\n" 5247 " check for possible regressions in migration code\n" 5248 " by comparing two such vmstate dumps.\n", 5249 QEMU_ARCH_ALL) 5250SRST 5251``-dump-vmstate file`` 5252 Dump json-encoded vmstate information for current machine type to 5253 file in file 5254ERST 5255 5256DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5257 "-enable-sync-profile\n" 5258 " enable synchronization profiling\n", 5259 QEMU_ARCH_ALL) 5260SRST 5261``-enable-sync-profile`` 5262 Enable synchronization profiling. 5263ERST 5264 5265#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5266DEF("perfmap", 0, QEMU_OPTION_perfmap, 5267 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5268 QEMU_ARCH_ALL) 5269SRST 5270``-perfmap`` 5271 Generate a map file for Linux perf tools that will allow basic profiling 5272 information to be broken down into basic blocks. 5273ERST 5274 5275DEF("jitdump", 0, QEMU_OPTION_jitdump, 5276 "-jitdump generate a jit-${pid}.dump file for perf\n", 5277 QEMU_ARCH_ALL) 5278SRST 5279``-jitdump`` 5280 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5281 names, line numbers and JITted code. 5282ERST 5283#endif 5284 5285DEFHEADING() 5286 5287DEFHEADING(Generic object creation:) 5288 5289DEF("object", HAS_ARG, QEMU_OPTION_object, 5290 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5291 " create a new object of type TYPENAME setting properties\n" 5292 " in the order they are specified. Note that the 'id'\n" 5293 " property must be set. These objects are placed in the\n" 5294 " '/objects' path.\n", 5295 QEMU_ARCH_ALL) 5296SRST 5297``-object typename[,prop1=value1,...]`` 5298 Create a new object of type typename setting properties in the order 5299 they are specified. Note that the 'id' property must be set. These 5300 objects are placed in the '/objects' path. 5301 5302 ``-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`` 5303 Creates a memory file backend object, which can be used to back 5304 the guest RAM with huge pages. 5305 5306 The ``id`` parameter is a unique ID that will be used to 5307 reference this memory region in other parameters, e.g. ``-numa``, 5308 ``-device nvdimm``, etc. 5309 5310 The ``size`` option provides the size of the memory region, and 5311 accepts common suffixes, e.g. ``500M``. 5312 5313 The ``mem-path`` provides the path to either a shared memory or 5314 huge page filesystem mount. 5315 5316 The ``share`` boolean option determines whether the memory 5317 region is marked as private to QEMU, or shared. The latter 5318 allows a co-operating external process to access the QEMU memory 5319 region. 5320 5321 Setting share=on might affect the ability to configure NUMA 5322 bindings for the memory backend under some circumstances, see 5323 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5324 source tree for additional details. 5325 5326 Setting the ``discard-data`` boolean option to on indicates that 5327 file contents can be destroyed when QEMU exits, to avoid 5328 unnecessarily flushing data to the backing file. Note that 5329 ``discard-data`` is only an optimization, and QEMU might not 5330 discard file contents if it aborts unexpectedly or is terminated 5331 using SIGKILL. 5332 5333 The ``merge`` boolean option enables memory merge, also known as 5334 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5335 the pages for memory deduplication. 5336 5337 Setting the ``dump`` boolean option to off excludes the memory 5338 from core dumps. This feature is also known as MADV\_DONTDUMP. 5339 5340 The ``prealloc`` boolean option enables memory preallocation. 5341 5342 The ``host-nodes`` option binds the memory range to a list of 5343 NUMA host nodes. 5344 5345 The ``policy`` option sets the NUMA policy to one of the 5346 following values: 5347 5348 ``default`` 5349 default host policy 5350 5351 ``preferred`` 5352 prefer the given host node list for allocation 5353 5354 ``bind`` 5355 restrict memory allocation to the given host node list 5356 5357 ``interleave`` 5358 interleave memory allocations across the given host node 5359 list 5360 5361 The ``align`` option specifies the base address alignment when 5362 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5363 ``2M``. Some backend store specified by ``mem-path`` requires an 5364 alignment different than the default one used by QEMU, eg the 5365 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5366 such cases, users can specify the required alignment via this 5367 option. 5368 5369 The ``offset`` option specifies the offset into the target file 5370 that the region starts at. You can use this parameter to back 5371 multiple regions with a single file. 5372 5373 The ``pmem`` option specifies whether the backing file specified 5374 by ``mem-path`` is in host persistent memory that can be 5375 accessed using the SNIA NVM programming model (e.g. Intel 5376 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5377 operations to guarantee the persistence of its own writes to 5378 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5379 migration). Also, we will map the backend-file with MAP\_SYNC 5380 flag, which ensures the file metadata is in sync for 5381 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5382 requires support from both the host kernel (since Linux kernel 5383 4.15) and the filesystem of ``mem-path`` mounted with DAX 5384 option. 5385 5386 The ``readonly`` option specifies whether the backing file is opened 5387 read-only or read-write (default). 5388 5389 The ``rom`` option specifies whether to create Read Only Memory 5390 (ROM) that cannot be modified by the VM. Any write attempts to such 5391 ROM will be denied. Most use cases want proper RAM instead of ROM. 5392 However, selected use cases, like R/O NVDIMMs, can benefit from 5393 ROM. If set to ``on``, create ROM; if set to ``off``, create 5394 writable RAM; if set to ``auto`` (default), the value of the 5395 ``readonly`` option is used. This option is primarily helpful when 5396 we want to have writable RAM in configurations that would 5397 traditionally create ROM before the ``rom`` option was introduced: 5398 VM templating, where we want to open a file readonly 5399 (``readonly=on``) and mark the memory to be private for QEMU 5400 (``share=off``). For this use case, we need writable RAM instead 5401 of ROM, and want to also set ``rom=off``. 5402 5403 ``-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`` 5404 Creates a memory backend object, which can be used to back the 5405 guest RAM. Memory backend objects offer more control than the 5406 ``-m`` option that is traditionally used to define guest RAM. 5407 Please refer to ``memory-backend-file`` for a description of the 5408 options. 5409 5410 ``-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`` 5411 Creates an anonymous memory file backend object, which allows 5412 QEMU to share the memory with an external process (e.g. when 5413 using vhost-user). The memory is allocated with memfd and 5414 optional sealing. (Linux only) 5415 5416 The ``seal`` option creates a sealed-file, that will block 5417 further resizing the memory ('on' by default). 5418 5419 The ``hugetlb`` option specify the file to be created resides in 5420 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5421 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5422 the hugetlb page size on systems that support multiple hugetlb 5423 page sizes (it must be a power of 2 value supported by the 5424 system). 5425 5426 In some versions of Linux, the ``hugetlb`` option is 5427 incompatible with the ``seal`` option (requires at least Linux 5428 4.16). 5429 5430 Please refer to ``memory-backend-file`` for a description of the 5431 other options. 5432 5433 The ``share`` boolean option is on by default with memfd. 5434 5435 ``-object memory-backend-shm,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`` 5436 Creates a POSIX shared memory backend object, which allows 5437 QEMU to share the memory with an external process (e.g. when 5438 using vhost-user). 5439 5440 ``memory-backend-shm`` is a more portable and less featureful version 5441 of ``memory-backend-memfd``. It can then be used in any POSIX system, 5442 especially when memfd is not supported. 5443 5444 Please refer to ``memory-backend-file`` for a description of the 5445 options. 5446 5447 The ``share`` boolean option is on by default with shm. Setting it to 5448 off will cause a failure during allocation because it is not supported 5449 by this backend. 5450 5451 ``-object iommufd,id=id[,fd=fd]`` 5452 Creates an iommufd backend which allows control of DMA mapping 5453 through the ``/dev/iommu`` device. 5454 5455 The ``id`` parameter is a unique ID which frontends (such as 5456 vfio-pci of vdpa) will use to connect with the iommufd backend. 5457 5458 The ``fd`` parameter is an optional pre-opened file descriptor 5459 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5460 across all subsystems, bringing the benefit of centralized 5461 reference counting. 5462 5463 ``-object rng-builtin,id=id`` 5464 Creates a random number generator backend which obtains entropy 5465 from QEMU builtin functions. The ``id`` parameter is a unique ID 5466 that will be used to reference this entropy backend from the 5467 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5468 uses this RNG backend. 5469 5470 ``-object rng-random,id=id,filename=/dev/random`` 5471 Creates a random number generator backend which obtains entropy 5472 from a device on the host. The ``id`` parameter is a unique ID 5473 that will be used to reference this entropy backend from the 5474 ``virtio-rng`` device. The ``filename`` parameter specifies 5475 which file to obtain entropy from and if omitted defaults to 5476 ``/dev/urandom``. 5477 5478 ``-object rng-egd,id=id,chardev=chardevid`` 5479 Creates a random number generator backend which obtains entropy 5480 from an external daemon running on the host. The ``id`` 5481 parameter is a unique ID that will be used to reference this 5482 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5483 parameter is the unique ID of a character device backend that 5484 provides the connection to the RNG daemon. 5485 5486 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5487 Creates a TLS anonymous credentials object, which can be used to 5488 provide TLS support on network backends. The ``id`` parameter is 5489 a unique ID which network backends will use to access the 5490 credentials. The ``endpoint`` is either ``server`` or ``client`` 5491 depending on whether the QEMU network backend that uses the 5492 credentials will be acting as a client or as a server. If 5493 ``verify-peer`` is enabled (the default) then once the handshake 5494 is completed, the peer credentials will be verified, though this 5495 is a no-op for anonymous credentials. 5496 5497 The dir parameter tells QEMU where to find the credential files. 5498 For server endpoints, this directory may contain a file 5499 dh-params.pem providing diffie-hellman parameters to use for the 5500 TLS server. If the file is missing, QEMU will generate a set of 5501 DH parameters at startup. This is a computationally expensive 5502 operation that consumes random pool entropy, so it is 5503 recommended that a persistent set of parameters be generated 5504 upfront and saved. 5505 5506 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5507 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5508 can be used to provide TLS support on network backends. The 5509 ``id`` parameter is a unique ID which network backends will use 5510 to access the credentials. The ``endpoint`` is either ``server`` 5511 or ``client`` depending on whether the QEMU network backend that 5512 uses the credentials will be acting as a client or as a server. 5513 For clients only, ``username`` is the username which will be 5514 sent to the server. If omitted it defaults to "qemu". 5515 5516 The dir parameter tells QEMU where to find the keys file. It is 5517 called "dir/keys.psk" and contains "username:key" pairs. This 5518 file can most easily be created using the GnuTLS ``psktool`` 5519 program. 5520 5521 For server endpoints, dir may also contain a file dh-params.pem 5522 providing diffie-hellman parameters to use for the TLS server. 5523 If the file is missing, QEMU will generate a set of DH 5524 parameters at startup. This is a computationally expensive 5525 operation that consumes random pool entropy, so it is 5526 recommended that a persistent set of parameters be generated up 5527 front and saved. 5528 5529 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5530 Creates a TLS anonymous credentials object, which can be used to 5531 provide TLS support on network backends. The ``id`` parameter is 5532 a unique ID which network backends will use to access the 5533 credentials. The ``endpoint`` is either ``server`` or ``client`` 5534 depending on whether the QEMU network backend that uses the 5535 credentials will be acting as a client or as a server. If 5536 ``verify-peer`` is enabled (the default) then once the handshake 5537 is completed, the peer credentials will be verified. With x509 5538 certificates, this implies that the clients must be provided 5539 with valid client certificates too. 5540 5541 The dir parameter tells QEMU where to find the credential files. 5542 For server endpoints, this directory may contain a file 5543 dh-params.pem providing diffie-hellman parameters to use for the 5544 TLS server. If the file is missing, QEMU will generate a set of 5545 DH parameters at startup. This is a computationally expensive 5546 operation that consumes random pool entropy, so it is 5547 recommended that a persistent set of parameters be generated 5548 upfront and saved. 5549 5550 For x509 certificate credentials the directory will contain 5551 further files providing the x509 certificates. The certificates 5552 must be stored in PEM format, in filenames ca-cert.pem, 5553 ca-crl.pem (optional), server-cert.pem (only servers), 5554 server-key.pem (only servers), client-cert.pem (only clients), 5555 and client-key.pem (only clients). 5556 5557 For the server-key.pem and client-key.pem files which contain 5558 sensitive private keys, it is possible to use an encrypted 5559 version by providing the passwordid parameter. This provides the 5560 ID of a previously created ``secret`` object containing the 5561 password for decryption. 5562 5563 The priority parameter allows to override the global default 5564 priority used by gnutls. This can be useful if the system 5565 administrator needs to use a weaker set of crypto priorities for 5566 QEMU without potentially forcing the weakness onto all 5567 applications. Or conversely if one wants wants a stronger 5568 default for QEMU than for all other applications, they can do 5569 this through this parameter. Its format is a gnutls priority 5570 string as described at 5571 https://gnutls.org/manual/html_node/Priority-Strings.html. 5572 5573 ``-object tls-cipher-suites,id=id,priority=priority`` 5574 Creates a TLS cipher suites object, which can be used to control 5575 the TLS cipher/protocol algorithms that applications are permitted 5576 to use. 5577 5578 The ``id`` parameter is a unique ID which frontends will use to 5579 access the ordered list of permitted TLS cipher suites from the 5580 host. 5581 5582 The ``priority`` parameter allows to override the global default 5583 priority used by gnutls. This can be useful if the system 5584 administrator needs to use a weaker set of crypto priorities for 5585 QEMU without potentially forcing the weakness onto all 5586 applications. Or conversely if one wants wants a stronger 5587 default for QEMU than for all other applications, they can do 5588 this through this parameter. Its format is a gnutls priority 5589 string as described at 5590 https://gnutls.org/manual/html_node/Priority-Strings.html. 5591 5592 An example of use of this object is to control UEFI HTTPS Boot. 5593 The tls-cipher-suites object exposes the ordered list of permitted 5594 TLS cipher suites from the host side to the guest firmware, via 5595 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5596 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5597 guest-side TLS. 5598 5599 In the following example, the priority at which the host-side policy 5600 is retrieved is given by the ``priority`` property. 5601 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5602 refer to /etc/crypto-policies/back-ends/gnutls.config. 5603 5604 .. parsed-literal:: 5605 5606 # |qemu_system| \\ 5607 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5608 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5609 5610 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5611 Interval t can't be 0, this filter batches the packet delivery: 5612 all packets arriving in a given interval on netdev netdevid are 5613 delayed until the end of the interval. Interval is in 5614 microseconds. ``status`` is optional that indicate whether the 5615 netfilter is on (enabled) or off (disabled), the default status 5616 for netfilter will be 'on'. 5617 5618 queue all\|rx\|tx is an option that can be applied to any 5619 netfilter. 5620 5621 ``all``: the filter is attached both to the receive and the 5622 transmit queue of the netdev (default). 5623 5624 ``rx``: the filter is attached to the receive queue of the 5625 netdev, where it will receive packets sent to the netdev. 5626 5627 ``tx``: the filter is attached to the transmit queue of the 5628 netdev, where it will receive packets sent by the netdev. 5629 5630 position head\|tail\|id=<id> is an option to specify where the 5631 filter should be inserted in the filter list. It can be applied 5632 to any netfilter. 5633 5634 ``head``: the filter is inserted at the head of the filter list, 5635 before any existing filters. 5636 5637 ``tail``: the filter is inserted at the tail of the filter list, 5638 behind any existing filters (default). 5639 5640 ``id=<id>``: the filter is inserted before or behind the filter 5641 specified by <id>, see the insert option below. 5642 5643 insert behind\|before is an option to specify where to insert 5644 the new filter relative to the one specified with 5645 position=id=<id>. It can be applied to any netfilter. 5646 5647 ``before``: insert before the specified filter. 5648 5649 ``behind``: insert behind the specified filter (default). 5650 5651 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5652 filter-mirror on netdev netdevid,mirror net packet to 5653 chardevchardevid, if it has the vnet\_hdr\_support flag, 5654 filter-mirror will mirror packet with vnet\_hdr\_len. 5655 5656 ``-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]`` 5657 filter-redirector on netdev netdevid,redirect filter's net 5658 packet to chardev chardevid,and redirect indev's packet to 5659 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5660 will redirect packet with vnet\_hdr\_len. Create a 5661 filter-redirector we need to differ outdev id from indev id, id 5662 can not be the same. we can just use indev or outdev, but at 5663 least one of indev or outdev need to be specified. 5664 5665 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5666 Filter-rewriter is a part of COLO project.It will rewrite tcp 5667 packet to secondary from primary to keep secondary tcp 5668 connection,and rewrite tcp packet to primary from secondary make 5669 tcp packet can be handled by client.if it has the 5670 vnet\_hdr\_support flag, we can parse packet with vnet header. 5671 5672 usage: colo secondary: -object 5673 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5674 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5675 filter-rewriter,id=rew0,netdev=hn0,queue=all 5676 5677 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5678 Dump the network traffic on netdev dev to the file specified by 5679 filename. At most len bytes (64k by default) per packet are 5680 stored. The file format is libpcap, so it can be analyzed with 5681 tools such as tcpdump or Wireshark. 5682 5683 ``-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}]`` 5684 Colo-compare gets packet from primary\_in chardevid and 5685 secondary\_in, then compare whether the payload of primary packet 5686 and secondary packet are the same. If same, it will output 5687 primary packet to out\_dev, else it will notify COLO-framework to do 5688 checkpoint and send primary packet to out\_dev. In order to 5689 improve efficiency, we need to put the task of comparison in 5690 another iothread. If it has the vnet\_hdr\_support flag, 5691 colo compare will send/recv packet with vnet\_hdr\_len. 5692 The compare\_timeout=@var{ms} determines the maximum time of the 5693 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5694 is to set the period of scanning expired primary node network packets. 5695 The max\_queue\_size=@var{size} is to set the max compare queue 5696 size depend on user environment. 5697 If user want to use Xen COLO, need to add the notify\_dev to 5698 notify Xen colo-frame to do checkpoint. 5699 5700 COLO-compare must be used with the help of filter-mirror, 5701 filter-redirector and filter-rewriter. 5702 5703 :: 5704 5705 KVM COLO 5706 5707 primary: 5708 -netdev tap,id=hn0,vhost=off 5709 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5710 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5711 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5712 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5713 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5714 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5715 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5716 -object iothread,id=iothread1 5717 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5718 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5719 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5720 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5721 5722 secondary: 5723 -netdev tap,id=hn0,vhost=off 5724 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5725 -chardev socket,id=red0,host=3.3.3.3,port=9003 5726 -chardev socket,id=red1,host=3.3.3.3,port=9004 5727 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5728 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5729 5730 5731 Xen COLO 5732 5733 primary: 5734 -netdev tap,id=hn0,vhost=off 5735 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5736 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5737 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5738 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5739 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5740 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5741 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5742 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5743 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5744 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5745 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5746 -object iothread,id=iothread1 5747 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5748 5749 secondary: 5750 -netdev tap,id=hn0,vhost=off 5751 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5752 -chardev socket,id=red0,host=3.3.3.3,port=9003 5753 -chardev socket,id=red1,host=3.3.3.3,port=9004 5754 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5755 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5756 5757 If you want to know the detail of above command line, you can 5758 read the colo-compare git log. 5759 5760 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5761 Creates a cryptodev backend which executes crypto operations from 5762 the QEMU cipher APIs. The id parameter is a unique ID that will 5763 be used to reference this cryptodev backend from the 5764 ``virtio-crypto`` device. The queues parameter is optional, 5765 which specify the queue number of cryptodev backend, the default 5766 of queues is 1. 5767 5768 .. parsed-literal:: 5769 5770 # |qemu_system| \\ 5771 [...] \\ 5772 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5773 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5774 [...] 5775 5776 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5777 Creates a vhost-user cryptodev backend, backed by a chardev 5778 chardevid. The id parameter is a unique ID that will be used to 5779 reference this cryptodev backend from the ``virtio-crypto`` 5780 device. The chardev should be a unix domain socket backed one. 5781 The vhost-user uses a specifically defined protocol to pass 5782 vhost ioctl replacement messages to an application on the other 5783 end of the socket. The queues parameter is optional, which 5784 specify the queue number of cryptodev backend for multiqueue 5785 vhost-user, the default of queues is 1. 5786 5787 .. parsed-literal:: 5788 5789 # |qemu_system| \\ 5790 [...] \\ 5791 -chardev socket,id=chardev0,path=/path/to/socket \\ 5792 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5793 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5794 [...] 5795 5796 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5797 \ 5798 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5799 Defines a secret to store a password, encryption key, or some 5800 other sensitive data. The sensitive data can either be passed 5801 directly via the data parameter, or indirectly via the file 5802 parameter. Using the data parameter is insecure unless the 5803 sensitive data is encrypted. 5804 5805 The sensitive data can be provided in raw format (the default), 5806 or base64. When encoded as JSON, the raw format only supports 5807 valid UTF-8 characters, so base64 is recommended for sending 5808 binary data. QEMU will convert from which ever format is 5809 provided to the format it needs internally. eg, an RBD password 5810 can be provided in raw format, even though it will be base64 5811 encoded when passed onto the RBD sever. 5812 5813 For added protection, it is possible to encrypt the data 5814 associated with a secret using the AES-256-CBC cipher. Use of 5815 encryption is indicated by providing the keyid and iv 5816 parameters. The keyid parameter provides the ID of a previously 5817 defined secret that contains the AES-256 decryption key. This 5818 key should be 32-bytes long and be base64 encoded. The iv 5819 parameter provides the random initialization vector used for 5820 encryption of this particular secret and should be a base64 5821 encrypted string of the 16-byte IV. 5822 5823 The simplest (insecure) usage is to provide the secret inline 5824 5825 .. parsed-literal:: 5826 5827 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5828 5829 The simplest secure usage is to provide the secret via a file 5830 5831 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5832 secret,id=sec0,file=mypasswd.txt,format=raw 5833 5834 For greater security, AES-256-CBC should be used. To illustrate 5835 usage, consider the openssl command line tool which can encrypt 5836 the data. Note that when encrypting, the plaintext must be 5837 padded to the cipher block size (32 bytes) using the standard 5838 PKCS#5/6 compatible padding algorithm. 5839 5840 First a master key needs to be created in base64 encoding: 5841 5842 :: 5843 5844 # openssl rand -base64 32 > key.b64 5845 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5846 5847 Each secret to be encrypted needs to have a random 5848 initialization vector generated. These do not need to be kept 5849 secret 5850 5851 :: 5852 5853 # openssl rand -base64 16 > iv.b64 5854 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5855 5856 The secret to be defined can now be encrypted, in this case 5857 we're telling openssl to base64 encode the result, but it could 5858 be left as raw bytes if desired. 5859 5860 :: 5861 5862 # SECRET=$(printf "letmein" | 5863 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5864 5865 When launching QEMU, create a master secret pointing to 5866 ``key.b64`` and specify that to be used to decrypt the user 5867 password. Pass the contents of ``iv.b64`` to the second secret 5868 5869 .. parsed-literal:: 5870 5871 # |qemu_system| \\ 5872 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5873 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5874 data=$SECRET,iv=$(<iv.b64) 5875 5876 ``-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]`` 5877 Create a Secure Encrypted Virtualization (SEV) guest object, 5878 which can be used to provide the guest memory encryption support 5879 on AMD processors. 5880 5881 When memory encryption is enabled, one of the physical address 5882 bit (aka the C-bit) is utilized to mark if a memory page is 5883 protected. The ``cbitpos`` is used to provide the C-bit 5884 position. The C-bit position is Host family dependent hence user 5885 must provide this value. On EPYC, the value should be 47. 5886 5887 When memory encryption is enabled, we loose certain bits in 5888 physical address space. The ``reduced-phys-bits`` is used to 5889 provide the number of bits we loose in physical address space. 5890 Similar to C-bit, the value is Host family dependent. On EPYC, 5891 a guest will lose a maximum of 1 bit, so the value should be 1. 5892 5893 The ``sev-device`` provides the device file to use for 5894 communicating with the SEV firmware running inside AMD Secure 5895 Processor. The default device is '/dev/sev'. If hardware 5896 supports memory encryption then /dev/sev devices are created by 5897 CCP driver. 5898 5899 The ``policy`` provides the guest policy to be enforced by the 5900 SEV firmware and restrict what configuration and operational 5901 commands can be performed on this guest by the hypervisor. The 5902 policy should be provided by the guest owner and is bound to the 5903 guest and cannot be changed throughout the lifetime of the 5904 guest. The default is 0. 5905 5906 If guest ``policy`` allows sharing the key with another SEV 5907 guest then ``handle`` can be use to provide handle of the guest 5908 from which to share the key. 5909 5910 The ``dh-cert-file`` and ``session-file`` provides the guest 5911 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5912 and session parameters are used for establishing a cryptographic 5913 session with the guest owner to negotiate keys used for 5914 attestation. The file must be encoded in base64. 5915 5916 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5917 cmdline to a designated guest firmware page for measured Linux 5918 boot with -kernel. The default is off. (Since 6.2) 5919 5920 e.g to launch a SEV guest 5921 5922 .. parsed-literal:: 5923 5924 # |qemu_system_x86| \\ 5925 ...... \\ 5926 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5927 -machine ...,memory-encryption=sev0 \\ 5928 ..... 5929 5930 ``-object authz-simple,id=id,identity=string`` 5931 Create an authorization object that will control access to 5932 network services. 5933 5934 The ``identity`` parameter is identifies the user and its format 5935 depends on the network service that authorization object is 5936 associated with. For authorizing based on TLS x509 certificates, 5937 the identity must be the x509 distinguished name. Note that care 5938 must be taken to escape any commas in the distinguished name. 5939 5940 An example authorization object to validate a x509 distinguished 5941 name would look like: 5942 5943 .. parsed-literal:: 5944 5945 # |qemu_system| \\ 5946 ... \\ 5947 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5948 ... 5949 5950 Note the use of quotes due to the x509 distinguished name 5951 containing whitespace, and escaping of ','. 5952 5953 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5954 Create an authorization object that will control access to 5955 network services. 5956 5957 The ``filename`` parameter is the fully qualified path to a file 5958 containing the access control list rules in JSON format. 5959 5960 An example set of rules that match against SASL usernames might 5961 look like: 5962 5963 :: 5964 5965 { 5966 "rules": [ 5967 { "match": "fred", "policy": "allow", "format": "exact" }, 5968 { "match": "bob", "policy": "allow", "format": "exact" }, 5969 { "match": "danb", "policy": "deny", "format": "glob" }, 5970 { "match": "dan*", "policy": "allow", "format": "exact" }, 5971 ], 5972 "policy": "deny" 5973 } 5974 5975 When checking access the object will iterate over all the rules 5976 and the first rule to match will have its ``policy`` value 5977 returned as the result. If no rules match, then the default 5978 ``policy`` value is returned. 5979 5980 The rules can either be an exact string match, or they can use 5981 the simple UNIX glob pattern matching to allow wildcards to be 5982 used. 5983 5984 If ``refresh`` is set to true the file will be monitored and 5985 automatically reloaded whenever its content changes. 5986 5987 As with the ``authz-simple`` object, the format of the identity 5988 strings being matched depends on the network service, but is 5989 usually a TLS x509 distinguished name, or a SASL username. 5990 5991 An example authorization object to validate a SASL username 5992 would look like: 5993 5994 .. parsed-literal:: 5995 5996 # |qemu_system| \\ 5997 ... \\ 5998 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5999 ... 6000 6001 ``-object authz-pam,id=id,service=string`` 6002 Create an authorization object that will control access to 6003 network services. 6004 6005 The ``service`` parameter provides the name of a PAM service to 6006 use for authorization. It requires that a file 6007 ``/etc/pam.d/service`` exist to provide the configuration for 6008 the ``account`` subsystem. 6009 6010 An example authorization object to validate a TLS x509 6011 distinguished name would look like: 6012 6013 .. parsed-literal:: 6014 6015 # |qemu_system| \\ 6016 ... \\ 6017 -object authz-pam,id=auth0,service=qemu-vnc \\ 6018 ... 6019 6020 There would then be a corresponding config file for PAM at 6021 ``/etc/pam.d/qemu-vnc`` that contains: 6022 6023 :: 6024 6025 account requisite pam_listfile.so item=user sense=allow \ 6026 file=/etc/qemu/vnc.allow 6027 6028 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 6029 of x509 distinguished names that are permitted access 6030 6031 :: 6032 6033 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 6034 6035 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 6036 Creates a dedicated event loop thread that devices can be 6037 assigned to. This is known as an IOThread. By default device 6038 emulation happens in vCPU threads or the main event loop thread. 6039 This can become a scalability bottleneck. IOThreads allow device 6040 emulation and I/O to run on other host CPUs. 6041 6042 The ``id`` parameter is a unique ID that will be used to 6043 reference this IOThread from ``-device ...,iothread=id``. 6044 Multiple devices can be assigned to an IOThread. Note that not 6045 all devices support an ``iothread`` parameter. 6046 6047 The ``query-iothreads`` QMP command lists IOThreads and reports 6048 their thread IDs so that the user can configure host CPU 6049 pinning/affinity. 6050 6051 IOThreads use an adaptive polling algorithm to reduce event loop 6052 latency. Instead of entering a blocking system call to monitor 6053 file descriptors and then pay the cost of being woken up when an 6054 event occurs, the polling algorithm spins waiting for events for 6055 a short time. The algorithm's default parameters are suitable 6056 for many cases but can be adjusted based on knowledge of the 6057 workload and/or host device latency. 6058 6059 The ``poll-max-ns`` parameter is the maximum number of 6060 nanoseconds to busy wait for events. Polling can be disabled by 6061 setting this value to 0. 6062 6063 The ``poll-grow`` parameter is the multiplier used to increase 6064 the polling time when the algorithm detects it is missing events 6065 due to not polling long enough. 6066 6067 The ``poll-shrink`` parameter is the divisor used to decrease 6068 the polling time when the algorithm detects it is spending too 6069 long polling without encountering events. 6070 6071 The ``aio-max-batch`` parameter is the maximum number of requests 6072 in a batch for the AIO engine, 0 means that the engine will use 6073 its default. 6074 6075 The IOThread parameters can be modified at run-time using the 6076 ``qom-set`` command (where ``iothread1`` is the IOThread's 6077 ``id``): 6078 6079 :: 6080 6081 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 6082ERST 6083 6084 6085HXCOMM This is the last statement. Insert new options before this line! 6086 6087#undef DEF 6088#undef DEFHEADING 6089#undef ARCHHEADING 6090
