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#ifdef CONFIG_POSIX 42 " aux-ram-share=on|off allocate auxiliary guest RAM as shared (default: off)\n" 43#endif 44 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 45 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 46 QEMU_ARCH_ALL) 47SRST 48``-machine [type=]name[,prop=value[,...]]`` 49 Select the emulated machine by name. Use ``-machine help`` to list 50 available machines. 51 52 For architectures which aim to support live migration compatibility 53 across releases, each release will introduce a new versioned machine 54 type. For example, the 2.8.0 release introduced machine types 55 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 56 57 To allow live migration of guests from QEMU version 2.8.0, to QEMU 58 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 59 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 60 skip multiple intermediate releases when upgrading, new releases of 61 QEMU will support machine types from many previous versions. 62 63 Supported machine properties are: 64 65 ``accel=accels1[:accels2[:...]]`` 66 This is used to enable an accelerator. Depending on the target 67 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 68 By default, tcg is used. If there is more than one accelerator 69 specified, the next one is used if the previous one fails to 70 initialize. 71 72 ``vmport=on|off|auto`` 73 Enables emulation of VMWare IO port, for vmmouse etc. auto says 74 to select the value based on accel and i8042. For accel=xen or 75 i8042=off the default is off otherwise the default is on. 76 77 ``dump-guest-core=on|off`` 78 Include guest memory in a core dump. The default is on. 79 80 ``mem-merge=on|off`` 81 Enables or disables memory merge support. This feature, when 82 supported by the host, de-duplicates identical memory pages 83 among VMs instances (enabled by default). 84 85 ``aes-key-wrap=on|off`` 86 Enables or disables AES key wrapping support on s390-ccw hosts. 87 This feature controls whether AES wrapping keys will be created 88 to allow execution of AES cryptographic functions. The default 89 is on. 90 91 ``dea-key-wrap=on|off`` 92 Enables or disables DEA key wrapping support on s390-ccw hosts. 93 This feature controls whether DEA wrapping keys will be created 94 to allow execution of DEA cryptographic functions. The default 95 is on. 96 97 ``nvdimm=on|off`` 98 Enables or disables NVDIMM support. The default is off. 99 100 ``memory-encryption=`` 101 Memory encryption object to use. The default is none. 102 103 ``hmat=on|off`` 104 Enables or disables ACPI Heterogeneous Memory Attribute Table 105 (HMAT) support. The default is off. 106 107 ``aux-ram-share=on|off`` 108 Allocate auxiliary guest RAM as an anonymous file that is 109 shareable with an external process. This option applies to 110 memory allocated as a side effect of creating various devices. 111 It does not apply to memory-backend-objects, whether explicitly 112 specified on the command line, or implicitly created by the -m 113 command line option. The default is off. 114 115 To use the cpr-transfer migration mode, you must set aux-ram-share=on. 116 117 ``memory-backend='id'`` 118 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 119 Allows to use a memory backend as main RAM. 120 121 For example: 122 :: 123 124 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 125 -machine memory-backend=pc.ram 126 -m 512M 127 128 Migration compatibility note: 129 130 * as backend id one shall use value of 'default-ram-id', advertised by 131 machine type (available via ``query-machines`` QMP command), if migration 132 to/from old QEMU (<5.0) is expected. 133 * for machine types 4.0 and older, user shall 134 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 135 if migration to/from old QEMU (<5.0) is expected. 136 137 For example: 138 :: 139 140 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 141 -machine memory-backend=pc.ram 142 -m 512M 143 144 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 145 Define a CXL Fixed Memory Window (CFMW). 146 147 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 148 149 They are regions of Host Physical Addresses (HPA) on a system which 150 may be interleaved across one or more CXL host bridges. The system 151 software will assign particular devices into these windows and 152 configure the downstream Host-managed Device Memory (HDM) decoders 153 in root ports, switch ports and devices appropriately to meet the 154 interleave requirements before enabling the memory devices. 155 156 ``targets.X=target`` provides the mapping to CXL host bridges 157 which may be identified by the id provided in the -device entry. 158 Multiple entries are needed to specify all the targets when 159 the fixed memory window represents interleaved memory. X is the 160 target index from 0. 161 162 ``size=size`` sets the size of the CFMW. This must be a multiple of 163 256MiB. The region will be aligned to 256MiB but the location is 164 platform and configuration dependent. 165 166 ``interleave-granularity=granularity`` sets the granularity of 167 interleave. Default 256 (bytes). Only 256, 512, 1k, 2k, 168 4k, 8k and 16k granularities supported. 169 170 Example: 171 172 :: 173 174 -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 175ERST 176 177DEF("M", HAS_ARG, QEMU_OPTION_M, 178 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 179 QEMU_ARCH_ALL) 180 181SRST 182``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 183 Define an SGX EPC section. 184ERST 185 186DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 187 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 188SRST 189``-cpu model`` 190 Select CPU model (``-cpu help`` for list and additional feature 191 selection) 192ERST 193 194DEF("accel", HAS_ARG, QEMU_OPTION_accel, 195 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 196 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 197 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 198 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 199 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 200 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 201 " split-wx=on|off (enable TCG split w^x mapping)\n" 202 " tb-size=n (TCG translation block cache size)\n" 203 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 204 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 205 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 206 " thread=single|multi (enable multi-threaded TCG)\n" 207 " device=path (KVM device path, default /dev/kvm)\n", QEMU_ARCH_ALL) 208SRST 209``-accel name[,prop=value[,...]]`` 210 This is used to enable an accelerator. Depending on the target 211 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 212 default, tcg is used. If there is more than one accelerator 213 specified, the next one is used if the previous one fails to 214 initialize. 215 216 ``igd-passthru=on|off`` 217 When Xen is in use, this option controls whether Intel 218 integrated graphics devices can be passed through to the guest 219 (default=off) 220 221 ``kernel-irqchip=on|off|split`` 222 Controls KVM in-kernel irqchip support. The default is full 223 acceleration of the interrupt controllers. On x86, split irqchip 224 reduces the kernel attack surface, at a performance cost for 225 non-MSI interrupts. Disabling the in-kernel irqchip completely 226 is not recommended except for debugging purposes. 227 228 ``kvm-shadow-mem=size`` 229 Defines the size of the KVM shadow MMU. 230 231 ``one-insn-per-tb=on|off`` 232 Makes the TCG accelerator put only one guest instruction into 233 each translation block. This slows down emulation a lot, but 234 can be useful in some situations, such as when trying to analyse 235 the logs produced by the ``-d`` option. 236 237 ``split-wx=on|off`` 238 Controls the use of split w^x mapping for the TCG code generation 239 buffer. Some operating systems require this to be enabled, and in 240 such a case this will default on. On other operating systems, this 241 will default off, but one may enable this for testing or debugging. 242 243 ``tb-size=n`` 244 Controls the size (in MiB) of the TCG translation block cache. 245 246 ``thread=single|multi`` 247 Controls number of TCG threads. When the TCG is multi-threaded 248 there will be one thread per vCPU therefore taking advantage of 249 additional host cores. The default is to enable multi-threading 250 where both the back-end and front-ends support it and no 251 incompatible TCG features have been enabled (e.g. 252 icount/replay). 253 254 ``dirty-ring-size=n`` 255 When the KVM accelerator is used, it controls the size of the per-vCPU 256 dirty page ring buffer (number of entries for each vCPU). It should 257 be a value that is power of two, and it should be 1024 or bigger (but 258 still less than the maximum value that the kernel supports). 4096 259 could be a good initial value if you have no idea which is the best. 260 Set this value to 0 to disable the feature. By default, this feature 261 is disabled (dirty-ring-size=0). When enabled, KVM will instead 262 record dirty pages in a bitmap. 263 264 ``eager-split-size=n`` 265 KVM implements dirty page logging at the PAGE_SIZE granularity and 266 enabling dirty-logging on a huge-page requires breaking it into 267 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 268 lazily by default. There are performance benefits in doing huge-page 269 split eagerly, especially in situations where TLBI costs associated 270 with break-before-make sequences are considerable and also if guest 271 workloads are read intensive. The size here specifies how many pages 272 to break at a time and needs to be a valid block size which is 273 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 274 respectively. Be wary of specifying a higher size as it will have an 275 impact on the memory. By default, this feature is disabled 276 (eager-split-size=0). 277 278 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 279 Enables or disables notify VM exit support on x86 host and specify 280 the corresponding notify window to trigger the VM exit if enabled. 281 ``run`` option enables the feature. It does nothing and continue 282 if the exit happens. ``internal-error`` option enables the feature. 283 It raises a internal error. ``disable`` option doesn't enable the feature. 284 This feature can mitigate the CPU stuck issue due to event windows don't 285 open up for a specified of time (i.e. notify-window). 286 Default: notify-vmexit=run,notify-window=0. 287 288 ``device=path`` 289 Sets the path to the KVM device node. Defaults to ``/dev/kvm``. This 290 option can be used to pass the KVM device to use via a file descriptor 291 by setting the value to ``/dev/fdset/NN``. 292 293ERST 294 295DEF("smp", HAS_ARG, QEMU_OPTION_smp, 296 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 297 " [,dies=dies][,clusters=clusters][,modules=modules][,cores=cores]\n" 298 " [,threads=threads]\n" 299 " set the number of initial CPUs to 'n' [default=1]\n" 300 " maxcpus= maximum number of total CPUs, including\n" 301 " offline CPUs for hotplug, etc\n" 302 " drawers= number of drawers on the machine board\n" 303 " books= number of books in one drawer\n" 304 " sockets= number of sockets in one book\n" 305 " dies= number of dies in one socket\n" 306 " clusters= number of clusters in one die\n" 307 " modules= number of modules in one cluster\n" 308 " cores= number of cores in one module\n" 309 " threads= number of threads in one core\n" 310 "Note: Different machines may have different subsets of the CPU topology\n" 311 " parameters supported, so the actual meaning of the supported parameters\n" 312 " will vary accordingly. For example, for a machine type that supports a\n" 313 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 314 " sequentially mean as below:\n" 315 " sockets means the number of sockets on the machine board\n" 316 " cores means the number of cores in one socket\n" 317 " threads means the number of threads in one core\n" 318 " For a particular machine type board, an expected CPU topology hierarchy\n" 319 " can be defined through the supported sub-option. Unsupported parameters\n" 320 " can also be provided in addition to the sub-option, but their values\n" 321 " must be set as 1 in the purpose of correct parsing.\n", 322 QEMU_ARCH_ALL) 323SRST 324``-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets][,dies=dies][,clusters=clusters][,modules=modules][,cores=cores][,threads=threads]`` 325 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 326 the machine type board. On boards supporting CPU hotplug, the optional 327 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 328 added at runtime. When both parameters are omitted, the maximum number 329 of CPUs will be calculated from the provided topology members and the 330 initial CPU count will match the maximum number. When only one of them 331 is given then the omitted one will be set to its counterpart's value. 332 Both parameters may be specified, but the maximum number of CPUs must 333 be equal to or greater than the initial CPU count. Product of the 334 CPU topology hierarchy must be equal to the maximum number of CPUs. 335 Both parameters are subject to an upper limit that is determined by 336 the specific machine type chosen. 337 338 To control reporting of CPU topology information, values of the topology 339 parameters can be specified. Machines may only support a subset of the 340 parameters and different machines may have different subsets supported 341 which vary depending on capacity of the corresponding CPU targets. So 342 for a particular machine type board, an expected topology hierarchy can 343 be defined through the supported sub-option. Unsupported parameters can 344 also be provided in addition to the sub-option, but their values must be 345 set as 1 in the purpose of correct parsing. 346 347 Either the initial CPU count, or at least one of the topology parameters 348 must be specified. The specified parameters must be greater than zero, 349 explicit configuration like "cpus=0" is not allowed. Values for any 350 omitted parameters will be computed from those which are given. 351 352 For example, the following sub-option defines a CPU topology hierarchy 353 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 354 core) for a machine that only supports sockets/cores/threads. 355 Some members of the option can be omitted but their values will be 356 automatically computed: 357 358 :: 359 360 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 361 362 The following sub-option defines a CPU topology hierarchy (2 sockets 363 totally on the machine, 2 dies per socket, 2 modules per die, 2 cores per 364 module, 2 threads per core) for PC machines which support sockets/dies 365 /modules/cores/threads. Some members of the option can be omitted but 366 their values will be automatically computed: 367 368 :: 369 370 -smp 32,sockets=2,dies=2,modules=2,cores=2,threads=2,maxcpus=32 371 372 The following sub-option defines a CPU topology hierarchy (2 sockets 373 totally on the machine, 2 clusters per socket, 2 cores per cluster, 374 2 threads per core) for ARM virt machines which support sockets/clusters 375 /cores/threads. Some members of the option can be omitted but their values 376 will be automatically computed: 377 378 :: 379 380 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 381 382 Historically preference was given to the coarsest topology parameters 383 when computing missing values (ie sockets preferred over cores, which 384 were preferred over threads), however, this behaviour is considered 385 liable to change. Prior to 6.2 the preference was sockets over cores 386 over threads. Since 6.2 the preference is cores over sockets over threads. 387 388 For example, the following option defines a machine board with 2 sockets 389 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 390 391 :: 392 393 -smp 2 394 395 Note: The cluster topology will only be generated in ACPI and exposed 396 to guest if it's explicitly specified in -smp. 397ERST 398 399DEF("numa", HAS_ARG, QEMU_OPTION_numa, 400 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 401 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 402 "-numa dist,src=source,dst=destination,val=distance\n" 403 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 404 "-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" 405 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 406 QEMU_ARCH_ALL) 407SRST 408``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 409 \ 410``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 411 \ 412``-numa dist,src=source,dst=destination,val=distance`` 413 \ 414``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 415 \ 416``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 417 \ 418``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 419 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 420 distance from a source node to a destination node. Set the ACPI 421 Heterogeneous Memory Attributes for the given nodes. 422 423 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 424 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 425 contiguous range of CPU indexes (or a single VCPU if lastcpu is 426 omitted). A non-contiguous set of VCPUs can be represented by 427 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 428 omitted on all nodes, VCPUs are automatically split between them. 429 430 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 431 NUMA node: 432 433 :: 434 435 -numa node,cpus=0-2,cpus=5 436 437 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 438 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 439 assign CPU objects to a node using topology layout properties of 440 CPU. The set of properties is machine specific, and depends on used 441 machine type/'\ ``smp``\ ' options. It could be queried with 442 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 443 property specifies node to which CPU object will be assigned, it's 444 required for node to be declared with '\ ``node``\ ' option before 445 it's used with '\ ``cpu``\ ' option. 446 447 For example: 448 449 :: 450 451 -M pc \ 452 -smp 1,sockets=2,maxcpus=2 \ 453 -numa node,nodeid=0 -numa node,nodeid=1 \ 454 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 455 456 '\ ``memdev``\ ' option assigns RAM from a given memory backend 457 device to a node. It is recommended to use '\ ``memdev``\ ' option 458 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 459 option provides better performance and more control over the 460 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 461 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 462 463 For compatibility reasons, legacy '\ ``mem``\ ' option is 464 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 465 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 466 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 467 option, and vice versa. 468 469 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 470 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 471 for '\ ``-numa node``\ ' without memory specified was removed. 472 473 '\ ``initiator``\ ' is an additional option that points to an 474 initiator NUMA node that has best performance (the lowest latency or 475 largest bandwidth) to this NUMA node. Note that this option can be 476 set only when the machine property 'hmat' is set to 'on'. 477 478 Following example creates a machine with 2 NUMA nodes, node 0 has 479 CPU. node 1 has only memory, and its initiator is node 0. Note that 480 because node 0 has CPU, by default the initiator of node 0 is itself 481 and must be itself. 482 483 :: 484 485 -machine hmat=on \ 486 -m 2G,slots=2,maxmem=4G \ 487 -object memory-backend-ram,size=1G,id=m0 \ 488 -object memory-backend-ram,size=1G,id=m1 \ 489 -numa node,nodeid=0,memdev=m0 \ 490 -numa node,nodeid=1,memdev=m1,initiator=0 \ 491 -smp 2,sockets=2,maxcpus=2 \ 492 -numa cpu,node-id=0,socket-id=0 \ 493 -numa cpu,node-id=0,socket-id=1 494 495 source and destination are NUMA node IDs. distance is the NUMA 496 distance from source to destination. The distance from a node to 497 itself is always 10. If any pair of nodes is given a distance, then 498 all pairs must be given distances. Although, when distances are only 499 given in one direction for each pair of nodes, then the distances in 500 the opposite directions are assumed to be the same. If, however, an 501 asymmetrical pair of distances is given for even one node pair, then 502 all node pairs must be provided distance values for both directions, 503 even when they are symmetrical. When a node is unreachable from 504 another node, set the pair's distance to 255. 505 506 Note that the -``numa`` option doesn't allocate any of the specified 507 resources, it just assigns existing resources to NUMA nodes. This 508 means that one still has to use the ``-m``, ``-smp`` options to 509 allocate RAM and VCPUs respectively. 510 511 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 512 Information between initiator and target NUMA nodes in ACPI 513 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 514 create memory requests, usually it has one or more processors. 515 Target NUMA node contains addressable memory. 516 517 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 518 the memory hierarchy of the target NUMA node: if hierarchy is 519 'memory', the structure represents the memory performance; if 520 hierarchy is 'first-level\|second-level\|third-level', this 521 structure represents aggregated performance of memory side caches 522 for each domain. type of 'data-type' is type of data represented by 523 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 524 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 525 the target memory; if 'hierarchy' is 526 'first-level\|second-level\|third-level', 'data-type' is 527 'access\|read\|write' hit latency or 'access\|read\|write' hit 528 bandwidth of the target memory side cache. 529 530 lat is latency value in nanoseconds. bw is bandwidth value, the 531 possible value and units are NUM[M\|G\|T], mean that the bandwidth 532 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 533 used suffix). Note that if latency or bandwidth value is 0, means 534 the corresponding latency or bandwidth information is not provided. 535 536 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 537 belongs. size is the size of memory side cache in bytes. level is 538 the cache level described in this structure, note that the cache 539 level 0 should not be used with '\ ``hmat-cache``\ ' option. 540 associativity is the cache associativity, the possible value is 541 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 542 is the write policy. line is the cache Line size in bytes. 543 544 For example, the following options describe 2 NUMA nodes. Node 0 has 545 2 cpus and a ram, node 1 has only a ram. The processors in node 0 546 access memory in node 0 with access-latency 5 nanoseconds, 547 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 548 memory in NUMA node 1 with access-latency 10 nanoseconds, 549 access-bandwidth is 100 MB/s. And for memory side cache information, 550 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 551 policy is write-back, the cache Line size is 8 bytes: 552 553 :: 554 555 -machine hmat=on \ 556 -m 2G \ 557 -object memory-backend-ram,size=1G,id=m0 \ 558 -object memory-backend-ram,size=1G,id=m1 \ 559 -smp 2,sockets=2,maxcpus=2 \ 560 -numa node,nodeid=0,memdev=m0 \ 561 -numa node,nodeid=1,memdev=m1,initiator=0 \ 562 -numa cpu,node-id=0,socket-id=0 \ 563 -numa cpu,node-id=0,socket-id=1 \ 564 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 565 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 566 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 567 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 568 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 569 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 570ERST 571 572DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 573 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 574 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 575SRST 576``-add-fd fd=fd,set=set[,opaque=opaque]`` 577 Add a file descriptor to an fd set. Valid options are: 578 579 ``fd=fd`` 580 This option defines the file descriptor of which a duplicate is 581 added to fd set. The file descriptor cannot be stdin, stdout, or 582 stderr. 583 584 ``set=set`` 585 This option defines the ID of the fd set to add the file 586 descriptor to. 587 588 ``opaque=opaque`` 589 This option defines a free-form string that can be used to 590 describe fd. 591 592 You can open an image using pre-opened file descriptors from an fd 593 set: 594 595 .. parsed-literal:: 596 597 |qemu_system| \\ 598 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 599 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 600 -drive file=/dev/fdset/2,index=0,media=disk 601ERST 602 603DEF("set", HAS_ARG, QEMU_OPTION_set, 604 "-set group.id.arg=value\n" 605 " set <arg> parameter for item <id> of type <group>\n" 606 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 607SRST 608``-set group.id.arg=value`` 609 Set parameter arg for item id of type group 610ERST 611 612DEF("global", HAS_ARG, QEMU_OPTION_global, 613 "-global driver.property=value\n" 614 "-global driver=driver,property=property,value=value\n" 615 " set a global default for a driver property\n", 616 QEMU_ARCH_ALL) 617SRST 618``-global driver.prop=value`` 619 \ 620``-global driver=driver,property=property,value=value`` 621 Set default value of driver's property prop to value, e.g.: 622 623 .. parsed-literal:: 624 625 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 626 627 In particular, you can use this to set driver properties for devices 628 which are created automatically by the machine model. To create a 629 device which is not created automatically and set properties on it, 630 use -``device``. 631 632 -global driver.prop=value is shorthand for -global 633 driver=driver,property=prop,value=value. The longhand syntax works 634 even when driver contains a dot. 635ERST 636 637DEF("boot", HAS_ARG, QEMU_OPTION_boot, 638 "-boot [order=drives][,once=drives][,menu=on|off]\n" 639 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 640 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 641 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 642 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 643 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 644 QEMU_ARCH_ALL) 645SRST 646``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 647 Specify boot order drives as a string of drive letters. Valid drive 648 letters depend on the target architecture. The x86 PC uses: a, b 649 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 650 (Etherboot from network adapter 1-4), hard disk boot is the default. 651 To apply a particular boot order only on the first startup, specify 652 it via ``once``. Note that the ``order`` or ``once`` parameter 653 should not be used together with the ``bootindex`` property of 654 devices, since the firmware implementations normally do not support 655 both at the same time. 656 657 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 658 as firmware/BIOS supports them. The default is non-interactive boot. 659 660 A splash picture could be passed to bios, enabling user to show it 661 as logo, when option splash=sp\_name is given and menu=on, If 662 firmware/BIOS supports them. Currently Seabios for X86 system 663 support it. limitation: The splash file could be a jpeg file or a 664 BMP file in 24 BPP format(true color). The resolution should be 665 supported by the SVGA mode, so the recommended is 320x240, 640x480, 666 800x640. 667 668 A timeout could be passed to bios, guest will pause for rb\_timeout 669 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 670 not reboot, qemu passes '-1' to bios by default. Currently Seabios 671 for X86 system support it. 672 673 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 674 it. This only effects when boot priority is changed by bootindex 675 options. The default is non-strict boot. 676 677 .. parsed-literal:: 678 679 # try to boot from network first, then from hard disk 680 |qemu_system_x86| -boot order=nc 681 # boot from CD-ROM first, switch back to default order after reboot 682 |qemu_system_x86| -boot once=d 683 # boot with a splash picture for 5 seconds. 684 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 685 686 Note: The legacy format '-boot drives' is still supported but its 687 use is discouraged as it may be removed from future versions. 688ERST 689 690DEF("m", HAS_ARG, QEMU_OPTION_m, 691 "-m [size=]megs[,slots=n,maxmem=size]\n" 692 " configure guest RAM\n" 693 " size: initial amount of guest memory\n" 694 " slots: number of hotplug slots (default: none)\n" 695 " maxmem: maximum amount of guest memory (default: none)\n" 696 " Note: Some architectures might enforce a specific granularity\n", 697 QEMU_ARCH_ALL) 698SRST 699``-m [size=]megs[,slots=n,maxmem=size]`` 700 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 701 Optionally, a suffix of "M" or "G" can be used to signify a value in 702 megabytes or gigabytes respectively. Optional pair slots, maxmem 703 could be used to set amount of hotpluggable memory slots and maximum 704 amount of memory. Note that maxmem must be aligned to the page size. 705 706 For example, the following command-line sets the guest startup RAM 707 size to 1GB, creates 3 slots to hotplug additional memory and sets 708 the maximum memory the guest can reach to 4GB: 709 710 .. parsed-literal:: 711 712 |qemu_system| -m 1G,slots=3,maxmem=4G 713 714 If slots and maxmem are not specified, memory hotplug won't be 715 enabled and the guest startup RAM will never increase. 716ERST 717 718DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 719 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 720SRST 721``-mem-path path`` 722 Allocate guest RAM from a temporarily created file in path. 723ERST 724 725DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 726 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 727 QEMU_ARCH_ALL) 728SRST 729``-mem-prealloc`` 730 Preallocate memory when using -mem-path. 731ERST 732 733DEF("k", HAS_ARG, QEMU_OPTION_k, 734 "-k language use keyboard layout (for example 'fr' for French)\n", 735 QEMU_ARCH_ALL) 736SRST 737``-k language`` 738 Use keyboard layout language (for example ``fr`` for French). This 739 option is only needed where it is not easy to get raw PC keycodes 740 (e.g. on Macs, with some X11 servers or with a VNC or curses 741 display). You don't normally need to use it on PC/Linux or 742 PC/Windows hosts. 743 744 The available layouts are: 745 746 :: 747 748 ar de-ch es fo fr-ca hu ja mk no pt-br sv 749 da en-gb et fr fr-ch is lt nl pl ru th 750 de en-us fi fr-be hr it lv nl-be pt sl tr 751 752 The default is ``en-us``. 753ERST 754 755 756DEF("audio", HAS_ARG, QEMU_OPTION_audio, 757 "-audio [driver=]driver[,prop[=value][,...]]\n" 758 " specifies default audio backend when `audiodev` is not\n" 759 " used to create a machine or sound device;" 760 " options are the same as for -audiodev\n" 761 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 762 " specifies the audio backend and device to use;\n" 763 " apart from 'model', options are the same as for -audiodev.\n" 764 " use '-audio model=help' to show possible devices.\n", 765 QEMU_ARCH_ALL) 766SRST 767``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 768 If the ``model`` option is specified, ``-audio`` is a shortcut 769 for configuring both the guest audio hardware and the host audio 770 backend in one go. The guest hardware model can be set with 771 ``model=modelname``. Use ``model=help`` to list the available 772 device types. 773 774 The following two example do exactly the same, to show how ``-audio`` 775 can be used to shorten the command line length: 776 777 .. parsed-literal:: 778 779 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 780 |qemu_system| -audio pa,model=sb16 781 782 If the ``model`` option is not specified, ``-audio`` is used to 783 configure a default audio backend that will be used whenever the 784 ``audiodev`` property is not set on a device or machine. In 785 particular, ``-audio none`` ensures that no audio is produced even 786 for machines that have embedded sound hardware. 787 788 In both cases, the driver option is the same as with the corresponding 789 ``-audiodev`` option below. Use ``driver=help`` to list the available 790 drivers. 791 792ERST 793 794DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 795 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 796 " specifies the audio backend to use\n" 797 " Use ``-audiodev help`` to list the available drivers\n" 798 " id= identifier of the backend\n" 799 " timer-period= timer period in microseconds\n" 800 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 801 " in|out.fixed-settings= use fixed settings for host audio\n" 802 " in|out.frequency= frequency to use with fixed settings\n" 803 " in|out.channels= number of channels to use with fixed settings\n" 804 " in|out.format= sample format to use with fixed settings\n" 805 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 806 " in|out.voices= number of voices to use\n" 807 " in|out.buffer-length= length of buffer in microseconds\n" 808 "-audiodev none,id=id,[,prop[=value][,...]]\n" 809 " dummy driver that discards all output\n" 810#ifdef CONFIG_AUDIO_ALSA 811 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 812 " in|out.dev= name of the audio device to use\n" 813 " in|out.period-length= length of period in microseconds\n" 814 " in|out.try-poll= attempt to use poll mode\n" 815 " threshold= threshold (in microseconds) when playback starts\n" 816#endif 817#ifdef CONFIG_AUDIO_COREAUDIO 818 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 819 " in|out.buffer-count= number of buffers\n" 820#endif 821#ifdef CONFIG_AUDIO_DSOUND 822 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 823 " latency= add extra latency to playback in microseconds\n" 824#endif 825#ifdef CONFIG_AUDIO_OSS 826 "-audiodev oss,id=id[,prop[=value][,...]]\n" 827 " in|out.dev= path of the audio device to use\n" 828 " in|out.buffer-count= number of buffers\n" 829 " in|out.try-poll= attempt to use poll mode\n" 830 " try-mmap= try using memory mapped access\n" 831 " exclusive= open device in exclusive mode\n" 832 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 833#endif 834#ifdef CONFIG_AUDIO_PA 835 "-audiodev pa,id=id[,prop[=value][,...]]\n" 836 " server= PulseAudio server address\n" 837 " in|out.name= source/sink device name\n" 838 " in|out.latency= desired latency in microseconds\n" 839#endif 840#ifdef CONFIG_AUDIO_PIPEWIRE 841 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 842 " in|out.name= source/sink device name\n" 843 " in|out.stream-name= name of pipewire stream\n" 844 " in|out.latency= desired latency in microseconds\n" 845#endif 846#ifdef CONFIG_AUDIO_SDL 847 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 848 " in|out.buffer-count= number of buffers\n" 849#endif 850#ifdef CONFIG_AUDIO_SNDIO 851 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 852#endif 853#ifdef CONFIG_SPICE 854 "-audiodev spice,id=id[,prop[=value][,...]]\n" 855#endif 856#ifdef CONFIG_DBUS_DISPLAY 857 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 858#endif 859 "-audiodev wav,id=id[,prop[=value][,...]]\n" 860 " path= path of wav file to record\n", 861 QEMU_ARCH_ALL) 862SRST 863``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 864 Adds a new audio backend driver identified by id. There are global 865 and driver specific properties. Some values can be set differently 866 for input and output, they're marked with ``in|out.``. You can set 867 the input's property with ``in.prop`` and the output's property with 868 ``out.prop``. For example: 869 870 :: 871 872 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 873 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 874 875 NOTE: parameter validation is known to be incomplete, in many cases 876 specifying an invalid option causes QEMU to print an error message 877 and continue emulation without sound. 878 879 Valid global options are: 880 881 ``id=identifier`` 882 Identifies the audio backend. 883 884 ``timer-period=period`` 885 Sets the timer period used by the audio subsystem in 886 microseconds. Default is 10000 (10 ms). 887 888 ``in|out.mixing-engine=on|off`` 889 Use QEMU's mixing engine to mix all streams inside QEMU and 890 convert audio formats when not supported by the backend. When 891 off, fixed-settings must be off too. Note that disabling this 892 option means that the selected backend must support multiple 893 streams and the audio formats used by the virtual cards, 894 otherwise you'll get no sound. It's not recommended to disable 895 this option unless you want to use 5.1 or 7.1 audio, as mixing 896 engine only supports mono and stereo audio. Default is on. 897 898 ``in|out.fixed-settings=on|off`` 899 Use fixed settings for host audio. When off, it will change 900 based on how the guest opens the sound card. In this case you 901 must not specify frequency, channels or format. Default is on. 902 903 ``in|out.frequency=frequency`` 904 Specify the frequency to use when using fixed-settings. Default 905 is 44100Hz. 906 907 ``in|out.channels=channels`` 908 Specify the number of channels to use when using fixed-settings. 909 Default is 2 (stereo). 910 911 ``in|out.format=format`` 912 Specify the sample format to use when using fixed-settings. 913 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 914 ``u32``, ``f32``. Default is ``s16``. 915 916 ``in|out.voices=voices`` 917 Specify the number of voices to use. Default is 1. 918 919 ``in|out.buffer-length=usecs`` 920 Sets the size of the buffer in microseconds. 921 922``-audiodev none,id=id[,prop[=value][,...]]`` 923 Creates a dummy backend that discards all outputs. This backend has 924 no backend specific properties. 925 926``-audiodev alsa,id=id[,prop[=value][,...]]`` 927 Creates backend using the ALSA. This backend is only available on 928 Linux. 929 930 ALSA specific options are: 931 932 ``in|out.dev=device`` 933 Specify the ALSA device to use for input and/or output. Default 934 is ``default``. 935 936 ``in|out.period-length=usecs`` 937 Sets the period length in microseconds. 938 939 ``in|out.try-poll=on|off`` 940 Attempt to use poll mode with the device. Default is on. 941 942 ``threshold=threshold`` 943 Threshold (in microseconds) when playback starts. Default is 0. 944 945``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 946 Creates a backend using Apple's Core Audio. This backend is only 947 available on Mac OS and only supports playback. 948 949 Core Audio specific options are: 950 951 ``in|out.buffer-count=count`` 952 Sets the count of the buffers. 953 954``-audiodev dsound,id=id[,prop[=value][,...]]`` 955 Creates a backend using Microsoft's DirectSound. This backend is 956 only available on Windows and only supports playback. 957 958 DirectSound specific options are: 959 960 ``latency=usecs`` 961 Add extra usecs microseconds latency to playback. Default is 962 10000 (10 ms). 963 964``-audiodev oss,id=id[,prop[=value][,...]]`` 965 Creates a backend using OSS. This backend is available on most 966 Unix-like systems. 967 968 OSS specific options are: 969 970 ``in|out.dev=device`` 971 Specify the file name of the OSS device to use. Default is 972 ``/dev/dsp``. 973 974 ``in|out.buffer-count=count`` 975 Sets the count of the buffers. 976 977 ``in|out.try-poll=on|of`` 978 Attempt to use poll mode with the device. Default is on. 979 980 ``try-mmap=on|off`` 981 Try using memory mapped device access. Default is off. 982 983 ``exclusive=on|off`` 984 Open the device in exclusive mode (vmix won't work in this 985 case). Default is off. 986 987 ``dsp-policy=policy`` 988 Sets the timing policy (between 0 and 10, where smaller number 989 means smaller latency but higher CPU usage). Use -1 to use 990 buffer sizes specified by ``buffer`` and ``buffer-count``. This 991 option is ignored if you do not have OSS 4. Default is 5. 992 993``-audiodev pa,id=id[,prop[=value][,...]]`` 994 Creates a backend using PulseAudio. This backend is available on 995 most systems. 996 997 PulseAudio specific options are: 998 999 ``server=server`` 1000 Sets the PulseAudio server to connect to. 1001 1002 ``in|out.name=sink`` 1003 Use the specified source/sink for recording/playback. 1004 1005 ``in|out.latency=usecs`` 1006 Desired latency in microseconds. The PulseAudio server will try 1007 to honor this value but actual latencies may be lower or higher. 1008 1009``-audiodev pipewire,id=id[,prop[=value][,...]]`` 1010 Creates a backend using PipeWire. This backend is available on 1011 most systems. 1012 1013 PipeWire specific options are: 1014 1015 ``in|out.latency=usecs`` 1016 Desired latency in microseconds. 1017 1018 ``in|out.name=sink`` 1019 Use the specified source/sink for recording/playback. 1020 1021 ``in|out.stream-name`` 1022 Specify the name of pipewire stream. 1023 1024``-audiodev sdl,id=id[,prop[=value][,...]]`` 1025 Creates a backend using SDL. This backend is available on most 1026 systems, but you should use your platform's native backend if 1027 possible. 1028 1029 SDL specific options are: 1030 1031 ``in|out.buffer-count=count`` 1032 Sets the count of the buffers. 1033 1034``-audiodev sndio,id=id[,prop[=value][,...]]`` 1035 Creates a backend using SNDIO. This backend is available on 1036 OpenBSD and most other Unix-like systems. 1037 1038 Sndio specific options are: 1039 1040 ``in|out.dev=device`` 1041 Specify the sndio device to use for input and/or output. Default 1042 is ``default``. 1043 1044 ``in|out.latency=usecs`` 1045 Sets the desired period length in microseconds. 1046 1047``-audiodev spice,id=id[,prop[=value][,...]]`` 1048 Creates a backend that sends audio through SPICE. This backend 1049 requires ``-spice`` and automatically selected in that case, so 1050 usually you can ignore this option. This backend has no backend 1051 specific properties. 1052 1053``-audiodev wav,id=id[,prop[=value][,...]]`` 1054 Creates a backend that writes audio to a WAV file. 1055 1056 Backend specific options are: 1057 1058 ``path=path`` 1059 Write recorded audio into the specified file. Default is 1060 ``qemu.wav``. 1061ERST 1062 1063DEF("device", HAS_ARG, QEMU_OPTION_device, 1064 "-device driver[,prop[=value][,...]]\n" 1065 " add device (based on driver)\n" 1066 " prop=value,... sets driver properties\n" 1067 " use '-device help' to print all possible drivers\n" 1068 " use '-device driver,help' to print all possible properties\n", 1069 QEMU_ARCH_ALL) 1070SRST 1071``-device driver[,prop[=value][,...]]`` 1072 Add device driver. prop=value sets driver properties. Valid 1073 properties depend on the driver. To get help on possible drivers and 1074 properties, use ``-device help`` and ``-device driver,help``. 1075 1076 Some drivers are: 1077 1078``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1079 Add an IPMI BMC. This is a simulation of a hardware management 1080 interface processor that normally sits on a system. It provides a 1081 watchdog and the ability to reset and power control the system. You 1082 need to connect this to an IPMI interface to make it useful 1083 1084 The IPMI slave address to use for the BMC. The default is 0x20. This 1085 address is the BMC's address on the I2C network of management 1086 controllers. If you don't know what this means, it is safe to ignore 1087 it. 1088 1089 ``id=id`` 1090 The BMC id for interfaces to use this device. 1091 1092 ``slave_addr=val`` 1093 Define slave address to use for the BMC. The default is 0x20. 1094 1095 ``sdrfile=file`` 1096 file containing raw Sensor Data Records (SDR) data. The default 1097 is none. 1098 1099 ``fruareasize=val`` 1100 size of a Field Replaceable Unit (FRU) area. The default is 1101 1024. 1102 1103 ``frudatafile=file`` 1104 file containing raw Field Replaceable Unit (FRU) inventory data. 1105 The default is none. 1106 1107 ``guid=uuid`` 1108 value for the GUID for the BMC, in standard UUID format. If this 1109 is set, get "Get GUID" command to the BMC will return it. 1110 Otherwise "Get GUID" will return an error. 1111 1112``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1113 Add a connection to an external IPMI BMC simulator. Instead of 1114 locally emulating the BMC like the above item, instead connect to an 1115 external entity that provides the IPMI services. 1116 1117 A connection is made to an external BMC simulator. If you do this, 1118 it is strongly recommended that you use the "reconnect-ms=" chardev 1119 option to reconnect to the simulator if the connection is lost. Note 1120 that if this is not used carefully, it can be a security issue, as 1121 the interface has the ability to send resets, NMIs, and power off 1122 the VM. It's best if QEMU makes a connection to an external 1123 simulator running on a secure port on localhost, so neither the 1124 simulator nor QEMU is exposed to any outside network. 1125 1126 See the "lanserv/README.vm" file in the OpenIPMI library for more 1127 details on the external interface. 1128 1129``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1130 Add a KCS IPMI interface on the ISA bus. This also adds a 1131 corresponding ACPI and SMBIOS entries, if appropriate. 1132 1133 ``bmc=id`` 1134 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1135 above. 1136 1137 ``ioport=val`` 1138 Define the I/O address of the interface. The default is 0xca0 1139 for KCS. 1140 1141 ``irq=val`` 1142 Define the interrupt to use. The default is 5. To disable 1143 interrupts, set this to 0. 1144 1145``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1146 Like the KCS interface, but defines a BT interface. The default port 1147 is 0xe4 and the default interrupt is 5. 1148 1149``-device pci-ipmi-kcs,bmc=id`` 1150 Add a KCS IPMI interface on the PCI bus. 1151 1152 ``bmc=id`` 1153 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1154 1155``-device pci-ipmi-bt,bmc=id`` 1156 Like the KCS interface, but defines a BT interface on the PCI bus. 1157 1158``-device intel-iommu[,option=...]`` 1159 This is only supported by ``-machine q35``, which will enable Intel VT-d 1160 emulation within the guest. It supports below options: 1161 1162 ``intremap=on|off`` (default: auto) 1163 This enables interrupt remapping feature. It's required to enable 1164 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1165 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1166 The default value is "auto", which will be decided by the mode of 1167 kernel-irqchip. 1168 1169 ``caching-mode=on|off`` (default: off) 1170 This enables caching mode for the VT-d emulated device. When 1171 caching-mode is enabled, each guest DMA buffer mapping will generate an 1172 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1173 a synchronous way. It is required for ``-device vfio-pci`` to work 1174 with the VT-d device, because host assigned devices requires to setup 1175 the DMA mapping on the host before guest DMA starts. 1176 1177 ``device-iotlb=on|off`` (default: off) 1178 This enables device-iotlb capability for the emulated VT-d device. So 1179 far virtio/vhost should be the only real user for this parameter, 1180 paired with ats=on configured for the device. 1181 1182 ``aw-bits=39|48`` (default: 39) 1183 This decides the address width of IOVA address space. The address 1184 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1185 4-level IOMMU page tables. 1186 1187 Please also refer to the wiki page for general scenarios of VT-d 1188 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1189 1190``-device virtio-iommu-pci[,option=...]`` 1191 This is only supported by ``-machine q35`` (x86_64) and ``-machine virt`` (ARM). 1192 It supports below options: 1193 1194 ``granule=val`` (possible values are 4k, 8k, 16k, 64k and host; default: host) 1195 This decides the default granule to be be exposed by the 1196 virtio-iommu. If host, the granule matches the host page size. 1197 1198 ``aw-bits=val`` (val between 32 and 64, default depends on machine) 1199 This decides the address width of the IOVA address space. 1200 1201ERST 1202 1203DEF("name", HAS_ARG, QEMU_OPTION_name, 1204 "-name string1[,process=string2][,debug-threads=on|off]\n" 1205 " set the name of the guest\n" 1206 " string1 sets the window title and string2 the process name\n" 1207 " When debug-threads is enabled, individual threads are given a separate name\n" 1208 " NOTE: The thread names are for debugging and not a stable API.\n", 1209 QEMU_ARCH_ALL) 1210SRST 1211``-name name`` 1212 Sets the name of the guest. This name will be displayed in the SDL 1213 window caption. The name will also be used for the VNC server. Also 1214 optionally set the top visible process name in Linux. Naming of 1215 individual threads can also be enabled on Linux to aid debugging. 1216ERST 1217 1218DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1219 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1220 " specify machine UUID\n", QEMU_ARCH_ALL) 1221SRST 1222``-uuid uuid`` 1223 Set system UUID. 1224ERST 1225 1226DEFHEADING() 1227 1228DEFHEADING(Block device options:) 1229 1230SRST 1231The QEMU block device handling options have a long history and 1232have gone through several iterations as the feature set and complexity 1233of the block layer have grown. Many online guides to QEMU often 1234reference older and deprecated options, which can lead to confusion. 1235 1236The most explicit way to describe disks is to use a combination of 1237``-device`` to specify the hardware device and ``-blockdev`` to 1238describe the backend. The device defines what the guest sees and the 1239backend describes how QEMU handles the data. It is the only guaranteed 1240stable interface for describing block devices and as such is 1241recommended for management tools and scripting. 1242 1243The ``-drive`` option combines the device and backend into a single 1244command line option which is a more human friendly. There is however no 1245interface stability guarantee although some older board models still 1246need updating to work with the modern blockdev forms. 1247 1248Older options like ``-hda`` are essentially macros which expand into 1249``-drive`` options for various drive interfaces. The original forms 1250bake in a lot of assumptions from the days when QEMU was emulating a 1251legacy PC, they are not recommended for modern configurations. 1252 1253ERST 1254 1255DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1256 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1257DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1258SRST 1259``-fda file`` 1260 \ 1261``-fdb file`` 1262 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1263 the System Emulation Users Guide). 1264ERST 1265 1266DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1267 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1268DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1269DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1270 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1271DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1272SRST 1273``-hda file`` 1274 \ 1275``-hdb file`` 1276 \ 1277``-hdc file`` 1278 \ 1279``-hdd file`` 1280 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1281 emulated machine (this is for example the IDE bus on most x86 machines, 1282 but it can also be SCSI, virtio or something else on other target 1283 architectures). See also the :ref:`disk images` chapter in the System 1284 Emulation Users Guide. 1285ERST 1286 1287DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1288 "-cdrom file use 'file' as CD-ROM image\n", 1289 QEMU_ARCH_ALL) 1290SRST 1291``-cdrom file`` 1292 Use file as CD-ROM image on the default bus of the emulated machine 1293 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1294 at the same time there). On systems that support it, you can use the 1295 host CD-ROM by using ``/dev/cdrom`` as filename. 1296ERST 1297 1298DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1299 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1300 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1301 " [,read-only=on|off][,auto-read-only=on|off]\n" 1302 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1303 " [,driver specific parameters...]\n" 1304 " configure a block backend\n", QEMU_ARCH_ALL) 1305SRST 1306``-blockdev option[,option[,option[,...]]]`` 1307 Define a new block driver node. Some of the options apply to all 1308 block drivers, other options are only accepted for a specific block 1309 driver. See below for a list of generic options and options for the 1310 most common block drivers. 1311 1312 Options that expect a reference to another node (e.g. ``file``) can 1313 be given in two ways. Either you specify the node name of an already 1314 existing node (file=node-name), or you define a new node inline, 1315 adding options for the referenced node after a dot 1316 (file.filename=path,file.aio=native). 1317 1318 A block driver node created with ``-blockdev`` can be used for a 1319 guest device by specifying its node name for the ``drive`` property 1320 in a ``-device`` argument that defines a block device. 1321 1322 ``Valid options for any block driver node:`` 1323 ``driver`` 1324 Specifies the block driver to use for the given node. 1325 1326 ``node-name`` 1327 This defines the name of the block driver node by which it 1328 will be referenced later. The name must be unique, i.e. it 1329 must not match the name of a different block driver node, or 1330 (if you use ``-drive`` as well) the ID of a drive. 1331 1332 If no node name is specified, it is automatically generated. 1333 The generated node name is not intended to be predictable 1334 and changes between QEMU invocations. For the top level, an 1335 explicit node name must be specified. 1336 1337 ``read-only`` 1338 Open the node read-only. Guest write attempts will fail. 1339 1340 Note that some block drivers support only read-only access, 1341 either generally or in certain configurations. In this case, 1342 the default value ``read-only=off`` does not work and the 1343 option must be specified explicitly. 1344 1345 ``auto-read-only`` 1346 If ``auto-read-only=on`` is set, QEMU may fall back to 1347 read-only usage even when ``read-only=off`` is requested, or 1348 even switch between modes as needed, e.g. depending on 1349 whether the image file is writable or whether a writing user 1350 is attached to the node. 1351 1352 ``force-share`` 1353 Override the image locking system of QEMU by forcing the 1354 node to utilize weaker shared access for permissions where 1355 it would normally request exclusive access. When there is 1356 the potential for multiple instances to have the same file 1357 open (whether this invocation of QEMU is the first or the 1358 second instance), both instances must permit shared access 1359 for the second instance to succeed at opening the file. 1360 1361 Enabling ``force-share=on`` requires ``read-only=on``. 1362 1363 ``cache.direct`` 1364 The host page cache can be avoided with ``cache.direct=on``. 1365 This will attempt to do disk IO directly to the guest's 1366 memory. QEMU may still perform an internal copy of the data. 1367 1368 ``cache.no-flush`` 1369 In case you don't care about data integrity over host 1370 failures, you can use ``cache.no-flush=on``. This option 1371 tells QEMU that it never needs to write any data to the disk 1372 but can instead keep things in cache. If anything goes 1373 wrong, like your host losing power, the disk storage getting 1374 disconnected accidentally, etc. your image will most 1375 probably be rendered unusable. 1376 1377 ``discard=discard`` 1378 discard is one of "ignore" (or "off") or "unmap" (or "on") 1379 and controls whether ``discard`` (also known as ``trim`` or 1380 ``unmap``) requests are ignored or passed to the filesystem. 1381 Some machine types may not support discard requests. 1382 1383 ``detect-zeroes=detect-zeroes`` 1384 detect-zeroes is "off", "on" or "unmap" and enables the 1385 automatic conversion of plain zero writes by the OS to 1386 driver specific optimized zero write commands. You may even 1387 choose "unmap" if discard is set to "unmap" to allow a zero 1388 write to be converted to an ``unmap`` operation. 1389 1390 ``Driver-specific options for file`` 1391 This is the protocol-level block driver for accessing regular 1392 files. 1393 1394 ``filename`` 1395 The path to the image file in the local filesystem 1396 1397 ``aio`` 1398 Specifies the AIO backend (threads/native/io_uring, 1399 default: threads) 1400 1401 ``locking`` 1402 Specifies whether the image file is protected with Linux OFD 1403 / POSIX locks. The default is to use the Linux Open File 1404 Descriptor API if available, otherwise no lock is applied. 1405 (auto/on/off, default: auto) 1406 1407 Example: 1408 1409 :: 1410 1411 -blockdev driver=file,node-name=disk,filename=disk.img 1412 1413 ``Driver-specific options for raw`` 1414 This is the image format block driver for raw images. It is 1415 usually stacked on top of a protocol level block driver such as 1416 ``file``. 1417 1418 ``file`` 1419 Reference to or definition of the data source block driver 1420 node (e.g. a ``file`` driver node) 1421 1422 Example 1: 1423 1424 :: 1425 1426 -blockdev driver=file,node-name=disk_file,filename=disk.img 1427 -blockdev driver=raw,node-name=disk,file=disk_file 1428 1429 Example 2: 1430 1431 :: 1432 1433 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1434 1435 ``Driver-specific options for qcow2`` 1436 This is the image format block driver for qcow2 images. It is 1437 usually stacked on top of a protocol level block driver such as 1438 ``file``. 1439 1440 ``file`` 1441 Reference to or definition of the data source block driver 1442 node (e.g. a ``file`` driver node) 1443 1444 ``backing`` 1445 Reference to or definition of the backing file block device 1446 (default is taken from the image file). It is allowed to 1447 pass ``null`` here in order to disable the default backing 1448 file. 1449 1450 ``lazy-refcounts`` 1451 Whether to enable the lazy refcounts feature (on/off; 1452 default is taken from the image file) 1453 1454 ``cache-size`` 1455 The maximum total size of the L2 table and refcount block 1456 caches in bytes (default: the sum of l2-cache-size and 1457 refcount-cache-size) 1458 1459 ``l2-cache-size`` 1460 The maximum size of the L2 table cache in bytes (default: if 1461 cache-size is not specified - 32M on Linux platforms, and 8M 1462 on non-Linux platforms; otherwise, as large as possible 1463 within the cache-size, while permitting the requested or the 1464 minimal refcount cache size) 1465 1466 ``refcount-cache-size`` 1467 The maximum size of the refcount block cache in bytes 1468 (default: 4 times the cluster size; or if cache-size is 1469 specified, the part of it which is not used for the L2 1470 cache) 1471 1472 ``cache-clean-interval`` 1473 Clean unused entries in the L2 and refcount caches. The 1474 interval is in seconds. The default value is 600 on 1475 supporting platforms, and 0 on other platforms. Setting it 1476 to 0 disables this feature. 1477 1478 ``pass-discard-request`` 1479 Whether discard requests to the qcow2 device should be 1480 forwarded to the data source (on/off; default: on if 1481 discard=unmap is specified, off otherwise) 1482 1483 ``pass-discard-snapshot`` 1484 Whether discard requests for the data source should be 1485 issued when a snapshot operation (e.g. deleting a snapshot) 1486 frees clusters in the qcow2 file (on/off; default: on) 1487 1488 ``pass-discard-other`` 1489 Whether discard requests for the data source should be 1490 issued on other occasions where a cluster gets freed 1491 (on/off; default: off) 1492 1493 ``discard-no-unref`` 1494 When enabled, data clusters will remain preallocated when they are 1495 no longer used, e.g. because they are discarded or converted to 1496 zero clusters. As usual, whether the old data is discarded or kept 1497 on the protocol level (i.e. in the image file) depends on the 1498 setting of the pass-discard-request option. Keeping the clusters 1499 preallocated prevents qcow2 fragmentation that would otherwise be 1500 caused by freeing and re-allocating them later. Besides potential 1501 performance degradation, such fragmentation can lead to increased 1502 allocation of clusters past the end of the image file, 1503 resulting in image files whose file length can grow much larger 1504 than their guest disk size would suggest. 1505 If image file length is of concern (e.g. when storing qcow2 1506 images directly on block devices), you should consider enabling 1507 this option. 1508 1509 ``overlap-check`` 1510 Which overlap checks to perform for writes to the image 1511 (none/constant/cached/all; default: cached). For details or 1512 finer granularity control refer to the QAPI documentation of 1513 ``blockdev-add``. 1514 1515 Example 1: 1516 1517 :: 1518 1519 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1520 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1521 1522 Example 2: 1523 1524 :: 1525 1526 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1527 1528 ``Driver-specific options for other drivers`` 1529 Please refer to the QAPI documentation of the ``blockdev-add`` 1530 QMP command. 1531ERST 1532 1533DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1534 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1535 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1536 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1537 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1538 " [,aio=threads|native|io_uring]\n" 1539 " [,readonly=on|off][,copy-on-read=on|off]\n" 1540 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1541 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1542 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1543 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1544 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1545 " [[,iops_size=is]]\n" 1546 " [[,group=g]]\n" 1547 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1548SRST 1549``-drive option[,option[,option[,...]]]`` 1550 Define a new drive. This includes creating a block driver node (the 1551 backend) as well as a guest device, and is mostly a shortcut for 1552 defining the corresponding ``-blockdev`` and ``-device`` options. 1553 1554 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1555 In addition, it knows the following options: 1556 1557 ``file=file`` 1558 This option defines which disk image (see the :ref:`disk images` 1559 chapter in the System Emulation Users Guide) to use with this drive. 1560 If the filename contains comma, you must double it (for instance, 1561 "file=my,,file" to use file "my,file"). 1562 1563 Special files such as iSCSI devices can be specified using 1564 protocol specific URLs. See the section for "Device URL Syntax" 1565 for more information. 1566 1567 ``if=interface`` 1568 This option defines on which type on interface the drive is 1569 connected. Available types are: ide, scsi, sd, mtd, floppy, 1570 pflash, virtio, none. 1571 1572 ``bus=bus,unit=unit`` 1573 These options define where is connected the drive by defining 1574 the bus number and the unit id. 1575 1576 ``index=index`` 1577 This option defines where the drive is connected by using an 1578 index in the list of available connectors of a given interface 1579 type. 1580 1581 ``media=media`` 1582 This option defines the type of the media: disk or cdrom. 1583 1584 ``snapshot=snapshot`` 1585 snapshot is "on" or "off" and controls snapshot mode for the 1586 given drive (see ``-snapshot``). 1587 1588 ``cache=cache`` 1589 cache is "none", "writeback", "unsafe", "directsync" or 1590 "writethrough" and controls how the host cache is used to access 1591 block data. This is a shortcut that sets the ``cache.direct`` 1592 and ``cache.no-flush`` options (as in ``-blockdev``), and 1593 additionally ``cache.writeback``, which provides a default for 1594 the ``write-cache`` option of block guest devices (as in 1595 ``-device``). The modes correspond to the following settings: 1596 1597 ============= =============== ============ ============== 1598 \ cache.writeback cache.direct cache.no-flush 1599 ============= =============== ============ ============== 1600 writeback on off off 1601 none on on off 1602 writethrough off off off 1603 directsync off on off 1604 unsafe on off on 1605 ============= =============== ============ ============== 1606 1607 The default mode is ``cache=writeback``. 1608 1609 ``aio=aio`` 1610 aio is "threads", "native", or "io_uring" and selects between pthread 1611 based disk I/O, native Linux AIO, or Linux io_uring API. 1612 1613 ``format=format`` 1614 Specify which disk format will be used rather than detecting the 1615 format. Can be used to specify format=raw to avoid interpreting 1616 an untrusted format header. 1617 1618 ``werror=action,rerror=action`` 1619 Specify which action to take on write and read errors. Valid 1620 actions are: "ignore" (ignore the error and try to continue), 1621 "stop" (pause QEMU), "report" (report the error to the guest), 1622 "enospc" (pause QEMU only if the host disk is full; report the 1623 error to the guest otherwise). The default setting is 1624 ``werror=enospc`` and ``rerror=report``. 1625 1626 ``copy-on-read=copy-on-read`` 1627 copy-on-read is "on" or "off" and enables whether to copy read 1628 backing file sectors into the image file. 1629 1630 ``bps=b,bps_rd=r,bps_wr=w`` 1631 Specify bandwidth throttling limits in bytes per second, either 1632 for all request types or for reads or writes only. Small values 1633 can lead to timeouts or hangs inside the guest. A safe minimum 1634 for disks is 2 MB/s. 1635 1636 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1637 Specify bursts in bytes per second, either for all request types 1638 or for reads or writes only. Bursts allow the guest I/O to spike 1639 above the limit temporarily. 1640 1641 ``iops=i,iops_rd=r,iops_wr=w`` 1642 Specify request rate limits in requests per second, either for 1643 all request types or for reads or writes only. 1644 1645 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1646 Specify bursts in requests per second, either for all request 1647 types or for reads or writes only. Bursts allow the guest I/O to 1648 spike above the limit temporarily. 1649 1650 ``iops_size=is`` 1651 Let every is bytes of a request count as a new request for iops 1652 throttling purposes. Use this option to prevent guests from 1653 circumventing iops limits by sending fewer but larger requests. 1654 1655 ``group=g`` 1656 Join a throttling quota group with given name g. All drives that 1657 are members of the same group are accounted for together. Use 1658 this option to prevent guests from circumventing throttling 1659 limits by using many small disks instead of a single larger 1660 disk. 1661 1662 By default, the ``cache.writeback=on`` mode is used. It will report 1663 data writes as completed as soon as the data is present in the host 1664 page cache. This is safe as long as your guest OS makes sure to 1665 correctly flush disk caches where needed. If your guest OS does not 1666 handle volatile disk write caches correctly and your host crashes or 1667 loses power, then the guest may experience data corruption. 1668 1669 For such guests, you should consider using ``cache.writeback=off``. 1670 This means that the host page cache will be used to read and write 1671 data, but write notification will be sent to the guest only after 1672 QEMU has made sure to flush each write to the disk. Be aware that 1673 this has a major impact on performance. 1674 1675 When using the ``-snapshot`` option, unsafe caching is always used. 1676 1677 Copy-on-read avoids accessing the same backing file sectors 1678 repeatedly and is useful when the backing file is over a slow 1679 network. By default copy-on-read is off. 1680 1681 Instead of ``-cdrom`` you can use: 1682 1683 .. parsed-literal:: 1684 1685 |qemu_system| -drive file=file,index=2,media=cdrom 1686 1687 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1688 1689 .. parsed-literal:: 1690 1691 |qemu_system| -drive file=file,index=0,media=disk 1692 |qemu_system| -drive file=file,index=1,media=disk 1693 |qemu_system| -drive file=file,index=2,media=disk 1694 |qemu_system| -drive file=file,index=3,media=disk 1695 1696 You can open an image using pre-opened file descriptors from an fd 1697 set: 1698 1699 .. parsed-literal:: 1700 1701 |qemu_system| \\ 1702 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1703 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1704 -drive file=/dev/fdset/2,index=0,media=disk 1705 1706 You can connect a CDROM to the slave of ide0: 1707 1708 .. parsed-literal:: 1709 1710 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1711 1712 If you don't specify the "file=" argument, you define an empty 1713 drive: 1714 1715 .. parsed-literal:: 1716 1717 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1718 1719 Instead of ``-fda``, ``-fdb``, you can use: 1720 1721 .. parsed-literal:: 1722 1723 |qemu_system_x86| -drive file=file,index=0,if=floppy 1724 |qemu_system_x86| -drive file=file,index=1,if=floppy 1725 1726 By default, interface is "ide" and index is automatically 1727 incremented: 1728 1729 .. parsed-literal:: 1730 1731 |qemu_system_x86| -drive file=a -drive file=b 1732 1733 is interpreted like: 1734 1735 .. parsed-literal:: 1736 1737 |qemu_system_x86| -hda a -hdb b 1738ERST 1739 1740DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1741 "-mtdblock file use 'file' as on-board Flash memory image\n", 1742 QEMU_ARCH_ALL) 1743SRST 1744``-mtdblock file`` 1745 Use file as on-board Flash memory image. 1746ERST 1747 1748DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1749 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1750SRST 1751``-sd file`` 1752 Use file as SecureDigital card image. 1753ERST 1754 1755DEF("snapshot", 0, QEMU_OPTION_snapshot, 1756 "-snapshot write to temporary files instead of disk image files\n", 1757 QEMU_ARCH_ALL) 1758SRST 1759``-snapshot`` 1760 Write to temporary files instead of disk image files. In this case, 1761 the raw disk image you use is not written back. You can however 1762 force the write back by pressing C-a s (see the :ref:`disk images` 1763 chapter in the System Emulation Users Guide). 1764 1765 .. warning:: 1766 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1767 to manually create snapshot images to attach to your blockdev). 1768 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1769 can use the 'snapshot' property on your drive declarations 1770 instead of this global option. 1771 1772ERST 1773 1774DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1775 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1776 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1777 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1778 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1779 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1780 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1781 " [[,throttling.iops-size=is]]\n" 1782 "-fsdev synth,id=id\n", 1783 QEMU_ARCH_ALL) 1784 1785SRST 1786``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1787 \ 1788``-fsdev synth,id=id[,readonly=on]`` 1789 Define a new file system device. Valid options are: 1790 1791 ``local`` 1792 Accesses to the filesystem are done by QEMU. 1793 1794 ``synth`` 1795 Synthetic filesystem, only used by QTests. 1796 1797 ``id=id`` 1798 Specifies identifier for this device. 1799 1800 ``path=path`` 1801 Specifies the export path for the file system device. Files 1802 under this path will be available to the 9p client on the guest. 1803 1804 ``security_model=security_model`` 1805 Specifies the security model to be used for this export path. 1806 Supported security models are "passthrough", "mapped-xattr", 1807 "mapped-file" and "none". In "passthrough" security model, files 1808 are stored using the same credentials as they are created on the 1809 guest. This requires QEMU to run as root. In "mapped-xattr" 1810 security model, some of the file attributes like uid, gid, mode 1811 bits and link target are stored as file attributes. For 1812 "mapped-file" these attributes are stored in the hidden 1813 .virtfs\_metadata directory. Directories exported by this 1814 security model cannot interact with other unix tools. "none" 1815 security model is same as passthrough except the sever won't 1816 report failures if it fails to set file attributes like 1817 ownership. Security model is mandatory only for local fsdriver. 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 ``fmode=fmode`` 1831 Specifies the default mode for newly created files on the host. 1832 Works only with security models "mapped-xattr" and 1833 "mapped-file". 1834 1835 ``dmode=dmode`` 1836 Specifies the default mode for newly created directories on the 1837 host. Works only with security models "mapped-xattr" and 1838 "mapped-file". 1839 1840 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1841 Specify bandwidth throttling limits in bytes per second, either 1842 for all request types or for reads or writes only. 1843 1844 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1845 Specify bursts in bytes per second, either for all request types 1846 or for reads or writes only. Bursts allow the guest I/O to spike 1847 above the limit temporarily. 1848 1849 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1850 Specify request rate limits in requests per second, either for 1851 all request types or for reads or writes only. 1852 1853 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1854 Specify bursts in requests per second, either for all request 1855 types or for reads or writes only. Bursts allow the guest I/O to 1856 spike above the limit temporarily. 1857 1858 ``throttling.iops-size=is`` 1859 Let every is bytes of a request count as a new request for iops 1860 throttling purposes. 1861 1862 -fsdev option is used along with -device driver "virtio-9p-...". 1863 1864``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1865 Options for virtio-9p-... driver are: 1866 1867 ``type`` 1868 Specifies the variant to be used. Supported values are "pci", 1869 "ccw" or "device", depending on the machine type. 1870 1871 ``fsdev=id`` 1872 Specifies the id value specified along with -fsdev option. 1873 1874 ``mount_tag=mount_tag`` 1875 Specifies the tag name to be used by the guest to mount this 1876 export point. 1877ERST 1878 1879DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1880 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1881 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1882 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1883 QEMU_ARCH_ALL) 1884 1885SRST 1886``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1887 \ 1888``-virtfs synth,mount_tag=mount_tag`` 1889 Define a new virtual filesystem device and expose it to the guest using 1890 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1891 directory on host is made directly accessible by guest as a pass-through 1892 file system by using the 9P network protocol for communication between 1893 host and guests, if desired even accessible, shared by several guests 1894 simultaneously. 1895 1896 Note that ``-virtfs`` is actually just a convenience shortcut for its 1897 generalized form ``-fsdev -device virtio-9p-pci``. 1898 1899 The general form of pass-through file system options are: 1900 1901 ``local`` 1902 Accesses to the filesystem are done by QEMU. 1903 1904 ``synth`` 1905 Synthetic filesystem, only used by QTests. 1906 1907 ``id=id`` 1908 Specifies identifier for the filesystem device 1909 1910 ``path=path`` 1911 Specifies the export path for the file system device. Files 1912 under this path will be available to the 9p client on the guest. 1913 1914 ``security_model=security_model`` 1915 Specifies the security model to be used for this export path. 1916 Supported security models are "passthrough", "mapped-xattr", 1917 "mapped-file" and "none". In "passthrough" security model, files 1918 are stored using the same credentials as they are created on the 1919 guest. This requires QEMU to run as root. In "mapped-xattr" 1920 security model, some of the file attributes like uid, gid, mode 1921 bits and link target are stored as file attributes. For 1922 "mapped-file" these attributes are stored in the hidden 1923 .virtfs\_metadata directory. Directories exported by this 1924 security model cannot interact with other unix tools. "none" 1925 security model is same as passthrough except the sever won't 1926 report failures if it fails to set file attributes like 1927 ownership. Security model is mandatory only for local fsdriver. 1928 1929 ``writeout=writeout`` 1930 This is an optional argument. The only supported value is 1931 "immediate". This means that host page cache will be used to 1932 read and write data but write notification will be sent to the 1933 guest only when the data has been reported as written by the 1934 storage subsystem. 1935 1936 ``readonly=on`` 1937 Enables exporting 9p share as a readonly mount for guests. By 1938 default read-write access is given. 1939 1940 ``fmode=fmode`` 1941 Specifies the default mode for newly created files on the host. 1942 Works only with security models "mapped-xattr" and 1943 "mapped-file". 1944 1945 ``dmode=dmode`` 1946 Specifies the default mode for newly created directories on the 1947 host. Works only with security models "mapped-xattr" and 1948 "mapped-file". 1949 1950 ``mount_tag=mount_tag`` 1951 Specifies the tag name to be used by the guest to mount this 1952 export point. 1953 1954 ``multidevs=multidevs`` 1955 Specifies how to deal with multiple devices being shared with a 1956 9p export. Supported behaviours are either "remap", "forbid" or 1957 "warn". The latter is the default behaviour on which virtfs 9p 1958 expects only one device to be shared with the same export, and 1959 if more than one device is shared and accessed via the same 9p 1960 export then only a warning message is logged (once) by qemu on 1961 host side. In order to avoid file ID collisions on guest you 1962 should either create a separate virtfs export for each device to 1963 be shared with guests (recommended way) or you might use "remap" 1964 instead which allows you to share multiple devices with only one 1965 export instead, which is achieved by remapping the original 1966 inode numbers from host to guest in a way that would prevent 1967 such collisions. Remapping inodes in such use cases is required 1968 because the original device IDs from host are never passed and 1969 exposed on guest. Instead all files of an export shared with 1970 virtfs always share the same device id on guest. So two files 1971 with identical inode numbers but from actually different devices 1972 on host would otherwise cause a file ID collision and hence 1973 potential misbehaviours on guest. "forbid" on the other hand 1974 assumes like "warn" that only one device is shared by the same 1975 export, however it will not only log a warning message but also 1976 deny access to additional devices on guest. Note though that 1977 "forbid" does currently not block all possible file access 1978 operations (e.g. readdir() would still return entries from other 1979 devices). 1980ERST 1981 1982DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1983 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1984 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1985 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1986 " [,timeout=timeout]\n" 1987 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1988 1989SRST 1990``-iscsi`` 1991 Configure iSCSI session parameters. 1992ERST 1993 1994DEFHEADING() 1995 1996DEFHEADING(USB convenience options:) 1997 1998DEF("usb", 0, QEMU_OPTION_usb, 1999 "-usb enable on-board USB host controller (if not enabled by default)\n", 2000 QEMU_ARCH_ALL) 2001SRST 2002``-usb`` 2003 Enable USB emulation on machine types with an on-board USB host 2004 controller (if not enabled by default). Note that on-board USB host 2005 controllers may not support USB 3.0. In this case 2006 ``-device qemu-xhci`` can be used instead on machines with PCI. 2007ERST 2008 2009DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2010 "-usbdevice name add the host or guest USB device 'name'\n", 2011 QEMU_ARCH_ALL) 2012SRST 2013``-usbdevice devname`` 2014 Add the USB device devname, and enable an on-board USB controller 2015 if possible and necessary (just like it can be done via 2016 ``-machine usb=on``). Note that this option is mainly intended for 2017 the user's convenience only. More fine-grained control can be 2018 achieved by selecting a USB host controller (if necessary) and the 2019 desired USB device via the ``-device`` option instead. For example, 2020 instead of using ``-usbdevice mouse`` it is possible to use 2021 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2022 to a USB 3.0 controller instead (at least on machines that support 2023 PCI and do not have an USB controller enabled by default yet). 2024 For more details, see the chapter about 2025 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2026 Possible devices for devname are: 2027 2028 ``braille`` 2029 Braille device. This will use BrlAPI to display the braille 2030 output on a real or fake device (i.e. it also creates a 2031 corresponding ``braille`` chardev automatically beside the 2032 ``usb-braille`` USB device). 2033 2034 ``keyboard`` 2035 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2036 2037 ``mouse`` 2038 Virtual Mouse. This will override the PS/2 mouse emulation when 2039 activated. 2040 2041 ``tablet`` 2042 Pointer device that uses absolute coordinates (like a 2043 touchscreen). This means QEMU is able to report the mouse 2044 position without having to grab the mouse. Also overrides the 2045 PS/2 mouse emulation when activated. 2046 2047 ``wacom-tablet`` 2048 Wacom PenPartner USB tablet. 2049 2050 2051ERST 2052 2053DEFHEADING() 2054 2055DEFHEADING(Display options:) 2056 2057DEF("display", HAS_ARG, QEMU_OPTION_display, 2058#if defined(CONFIG_SPICE) 2059 "-display spice-app[,gl=on|off]\n" 2060#endif 2061#if defined(CONFIG_SDL) 2062 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2063 " [,window-close=on|off]\n" 2064#endif 2065#if defined(CONFIG_GTK) 2066 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2067 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2068 " [,show-menubar=on|off][,zoom-to-fit=on|off]\n" 2069#endif 2070#if defined(CONFIG_VNC) 2071 "-display vnc=<display>[,<optargs>]\n" 2072#endif 2073#if defined(CONFIG_CURSES) 2074 "-display curses[,charset=<encoding>]\n" 2075#endif 2076#if defined(CONFIG_COCOA) 2077 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2078 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2079 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2080#endif 2081#if defined(CONFIG_OPENGL) 2082 "-display egl-headless[,rendernode=<file>]\n" 2083#endif 2084#if defined(CONFIG_DBUS_DISPLAY) 2085 "-display dbus[,addr=<dbusaddr>]\n" 2086 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2087#endif 2088 "-display none\n" 2089 " select display backend type\n" 2090 " The default display is equivalent to\n " 2091#if defined(CONFIG_GTK) 2092 "\"-display gtk\"\n" 2093#elif defined(CONFIG_SDL) 2094 "\"-display sdl\"\n" 2095#elif defined(CONFIG_COCOA) 2096 "\"-display cocoa\"\n" 2097#elif defined(CONFIG_VNC) 2098 "\"-vnc localhost:0,to=99,id=default\"\n" 2099#else 2100 "\"-display none\"\n" 2101#endif 2102 , QEMU_ARCH_ALL) 2103SRST 2104``-display type`` 2105 Select type of display to use. Use ``-display help`` to list the available 2106 display types. Valid values for type are 2107 2108 ``spice-app[,gl=on|off]`` 2109 Start QEMU as a Spice server and launch the default Spice client 2110 application. The Spice server will redirect the serial consoles 2111 and QEMU monitors. (Since 4.0) 2112 2113 ``dbus`` 2114 Export the display over D-Bus interfaces. (Since 7.0) 2115 2116 The connection is registered with the "org.qemu" name (and queued when 2117 already owned). 2118 2119 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2120 2121 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2122 2123 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2124 will share framebuffers with DMABUF file descriptors). 2125 2126 ``sdl`` 2127 Display video output via SDL (usually in a separate graphics 2128 window; see the SDL documentation for other possibilities). 2129 Valid parameters are: 2130 2131 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2132 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2133 either ``lshift-lctrl-lalt`` or ``rctrl``. 2134 2135 ``gl=on|off|core|es`` : Use OpenGL for displaying 2136 2137 ``show-cursor=on|off`` : Force showing the mouse cursor 2138 2139 ``window-close=on|off`` : Allow to quit qemu with window close button 2140 2141 ``gtk`` 2142 Display video output in a GTK window. This interface provides 2143 drop-down menus and other UI elements to configure and control 2144 the VM during runtime. Valid parameters are: 2145 2146 ``full-screen=on|off`` : Start in fullscreen mode 2147 2148 ``gl=on|off`` : Use OpenGL for displaying 2149 2150 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2151 2152 ``show-tabs=on|off`` : Display the tab bar for switching between the 2153 various graphical interfaces (e.g. VGA and 2154 virtual console character devices) by default. 2155 2156 ``show-cursor=on|off`` : Force showing the mouse cursor 2157 2158 ``window-close=on|off`` : Allow to quit qemu with window close button 2159 2160 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2161 2162 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2163 defaults to "off" 2164 2165 ``curses[,charset=<encoding>]`` 2166 Display video output via curses. For graphics device models 2167 which support a text mode, QEMU can display this output using a 2168 curses/ncurses interface. Nothing is displayed when the graphics 2169 device is in graphical mode or if the graphics device does not 2170 support a text mode. Generally only the VGA device models 2171 support text mode. The font charset used by the guest can be 2172 specified with the ``charset`` option, for example 2173 ``charset=CP850`` for IBM CP850 encoding. The default is 2174 ``CP437``. 2175 2176 ``cocoa`` 2177 Display video output in a Cocoa window. Mac only. This interface 2178 provides drop-down menus and other UI elements to configure and 2179 control the VM during runtime. Valid parameters are: 2180 2181 ``full-grab=on|off`` : Capture all key presses, including system combos. 2182 This requires accessibility permissions, since it 2183 performs a global grab on key events. 2184 (default: off) See 2185 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2186 2187 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2188 key codes match their position on non-Mac 2189 keyboards and you can use Meta/Super and Alt 2190 where you expect them. (default: off) 2191 2192 ``show-cursor=on|off`` : Force showing the mouse cursor 2193 2194 ``left-command-key=on|off`` : Disable forwarding left command key to host 2195 2196 ``full-screen=on|off`` : Start in fullscreen mode 2197 2198 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2199 defaults to "off" 2200 2201 ``egl-headless[,rendernode=<file>]`` 2202 Offload all OpenGL operations to a local DRI device. For any 2203 graphical display, this display needs to be paired with either 2204 VNC or SPICE displays. 2205 2206 ``vnc=<display>`` 2207 Start a VNC server on display <display> 2208 2209 ``none`` 2210 Do not display video output. The guest will still see an 2211 emulated graphics card, but its output will not be displayed to 2212 the QEMU user. This option differs from the -nographic option in 2213 that it only affects what is done with video output; -nographic 2214 also changes the destination of the serial and parallel port 2215 data. 2216ERST 2217 2218DEF("nographic", 0, QEMU_OPTION_nographic, 2219 "-nographic disable graphical output and redirect serial I/Os to console\n", 2220 QEMU_ARCH_ALL) 2221SRST 2222``-nographic`` 2223 Normally, if QEMU is compiled with graphical window support, it 2224 displays output such as guest graphics, guest console, and the QEMU 2225 monitor in a window. With this option, you can totally disable 2226 graphical output so that QEMU is a simple command line application. 2227 The emulated serial port is redirected on the console and muxed with 2228 the monitor (unless redirected elsewhere explicitly). Therefore, you 2229 can still use QEMU to debug a Linux kernel with a serial console. 2230 Use C-a h for help on switching between the console and monitor. 2231ERST 2232 2233#ifdef CONFIG_SPICE 2234DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2235 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2236 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2237 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2238 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2239 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2240 " [,tls-ciphers=<list>]\n" 2241 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2242 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2243 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2244 " [,password-secret=<secret-id>]\n" 2245 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2246 " [,jpeg-wan-compression=[auto|never|always]]\n" 2247 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2248 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2249 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2250 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2251 " [,gl=[on|off]][,rendernode=<file>]\n" 2252 " enable spice\n" 2253 " at least one of {port, tls-port} is mandatory\n", 2254 QEMU_ARCH_ALL) 2255#endif 2256SRST 2257``-spice option[,option[,...]]`` 2258 Enable the spice remote desktop protocol. Valid options are 2259 2260 ``port=<nr>`` 2261 Set the TCP port spice is listening on for plaintext channels. 2262 2263 ``addr=<addr>`` 2264 Set the IP address spice is listening on. Default is any 2265 address. 2266 2267 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2268 Force using the specified IP version. 2269 2270 ``password-secret=<secret-id>`` 2271 Set the ID of the ``secret`` object containing the password 2272 you need to authenticate. 2273 2274 ``sasl=on|off`` 2275 Require that the client use SASL to authenticate with the spice. 2276 The exact choice of authentication method used is controlled 2277 from the system / user's SASL configuration file for the 'qemu' 2278 service. This is typically found in /etc/sasl2/qemu.conf. If 2279 running QEMU as an unprivileged user, an environment variable 2280 SASL\_CONF\_PATH can be used to make it search alternate 2281 locations for the service config. While some SASL auth methods 2282 can also provide data encryption (eg GSSAPI), it is recommended 2283 that SASL always be combined with the 'tls' and 'x509' settings 2284 to enable use of SSL and server certificates. This ensures a 2285 data encryption preventing compromise of authentication 2286 credentials. 2287 2288 ``disable-ticketing=on|off`` 2289 Allow client connects without authentication. 2290 2291 ``disable-copy-paste=on|off`` 2292 Disable copy paste between the client and the guest. 2293 2294 ``disable-agent-file-xfer=on|off`` 2295 Disable spice-vdagent based file-xfer between the client and the 2296 guest. 2297 2298 ``tls-port=<nr>`` 2299 Set the TCP port spice is listening on for encrypted channels. 2300 2301 ``x509-dir=<dir>`` 2302 Set the x509 file directory. Expects same filenames as -vnc 2303 $display,x509=$dir 2304 2305 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2306 The x509 file names can also be configured individually. 2307 2308 ``tls-ciphers=<list>`` 2309 Specify which ciphers to use. 2310 2311 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2312 Force specific channel to be used with or without TLS 2313 encryption. The options can be specified multiple times to 2314 configure multiple channels. The special name "default" can be 2315 used to set the default mode. For channels which are not 2316 explicitly forced into one mode the spice client is allowed to 2317 pick tls/plaintext as he pleases. 2318 2319 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2320 Configure image compression (lossless). Default is auto\_glz. 2321 2322 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2323 Configure wan image compression (lossy for slow links). Default 2324 is auto. 2325 2326 ``streaming-video=[off|all|filter]`` 2327 Configure video stream detection. Default is off. 2328 2329 ``agent-mouse=[on|off]`` 2330 Enable/disable passing mouse events via vdagent. Default is on. 2331 2332 ``playback-compression=[on|off]`` 2333 Enable/disable audio stream compression (using celt 0.5.1). 2334 Default is on. 2335 2336 ``seamless-migration=[on|off]`` 2337 Enable/disable spice seamless migration. Default is off. 2338 2339 ``gl=[on|off]`` 2340 Enable/disable OpenGL context. Default is off. 2341 2342 ``rendernode=<file>`` 2343 DRM render node for OpenGL rendering. If not specified, it will 2344 pick the first available. (Since 2.9) 2345ERST 2346 2347DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2348 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2349 " select video card type\n", QEMU_ARCH_ALL) 2350SRST 2351``-vga type`` 2352 Select type of VGA card to emulate. Valid values for type are 2353 2354 ``cirrus`` 2355 Cirrus Logic GD5446 Video card. All Windows versions starting 2356 from Windows 95 should recognize and use this graphic card. For 2357 optimal performances, use 16 bit color depth in the guest and 2358 the host OS. (This card was the default before QEMU 2.2) 2359 2360 ``std`` 2361 Standard VGA card with Bochs VBE extensions. If your guest OS 2362 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2363 you want to use high resolution modes (>= 1280x1024x16) then you 2364 should use this option. (This card is the default since QEMU 2365 2.2) 2366 2367 ``vmware`` 2368 VMWare SVGA-II compatible adapter. Use it if you have 2369 sufficiently recent XFree86/XOrg server or Windows guest with a 2370 driver for this card. 2371 2372 ``qxl`` 2373 QXL paravirtual graphic card. It is VGA compatible (including 2374 VESA 2.0 VBE support). Works best with qxl guest drivers 2375 installed though. Recommended choice when using the spice 2376 protocol. 2377 2378 ``tcx`` 2379 (sun4m only) Sun TCX framebuffer. This is the default 2380 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2381 colour depths at a fixed resolution of 1024x768. 2382 2383 ``cg3`` 2384 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2385 framebuffer for sun4m machines available in both 1024x768 2386 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2387 wishing to run older Solaris versions. 2388 2389 ``virtio`` 2390 Virtio VGA card. 2391 2392 ``none`` 2393 Disable VGA card. 2394ERST 2395 2396DEF("full-screen", 0, QEMU_OPTION_full_screen, 2397 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2398SRST 2399``-full-screen`` 2400 Start in full screen. 2401ERST 2402 2403DEF("g", HAS_ARG, QEMU_OPTION_g , 2404 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2405 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2406SRST 2407``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2408 Set the initial graphical resolution and depth (PPC, SPARC only). 2409 2410 For PPC the default is 800x600x32. 2411 2412 For SPARC with the TCX graphics device, the default is 1024x768x8 2413 with the option of 1024x768x24. For cgthree, the default is 2414 1024x768x8 with the option of 1152x900x8 for people who wish to use 2415 OBP. 2416ERST 2417 2418#ifdef CONFIG_VNC 2419DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2420 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2421#endif 2422SRST 2423``-vnc display[,option[,option[,...]]]`` 2424 Normally, if QEMU is compiled with graphical window support, it 2425 displays output such as guest graphics, guest console, and the QEMU 2426 monitor in a window. With this option, you can have QEMU listen on 2427 VNC display display and redirect the VGA display over the VNC 2428 session. It is very useful to enable the usb tablet device when 2429 using this option (option ``-device usb-tablet``). When using the 2430 VNC display, you must use the ``-k`` parameter to set the keyboard 2431 layout if you are not using en-us. Valid syntax for the display is 2432 2433 ``to=L`` 2434 With this option, QEMU will try next available VNC displays, 2435 until the number L, if the originally defined "-vnc display" is 2436 not available, e.g. port 5900+display is already used by another 2437 application. By default, to=0. 2438 2439 ``host:d`` 2440 TCP connections will only be allowed from host on display d. By 2441 convention the TCP port is 5900+d. Optionally, host can be 2442 omitted in which case the server will accept connections from 2443 any host. 2444 2445 ``unix:path`` 2446 Connections will be allowed over UNIX domain sockets where path 2447 is the location of a unix socket to listen for connections on. 2448 2449 ``none`` 2450 VNC is initialized but not started. The monitor ``change`` 2451 command can be used to later start the VNC server. 2452 2453 Following the display value there may be one or more option flags 2454 separated by commas. Valid options are 2455 2456 ``reverse=on|off`` 2457 Connect to a listening VNC client via a "reverse" connection. 2458 The client is specified by the display. For reverse network 2459 connections (host:d,``reverse``), the d argument is a TCP port 2460 number, not a display number. 2461 2462 ``websocket=on|off`` 2463 Opens an additional TCP listening port dedicated to VNC 2464 Websocket connections. If a bare websocket option is given, the 2465 Websocket port is 5700+display. An alternative port can be 2466 specified with the syntax ``websocket``\ =port. 2467 2468 If host is specified connections will only be allowed from this 2469 host. It is possible to control the websocket listen address 2470 independently, using the syntax ``websocket``\ =host:port. 2471 2472 Websocket could be allowed over UNIX domain socket, using the syntax 2473 ``websocket``\ =unix:path, where path is the location of a unix socket 2474 to listen for connections on. 2475 2476 If no TLS credentials are provided, the websocket connection 2477 runs in unencrypted mode. If TLS credentials are provided, the 2478 websocket connection requires encrypted client connections. 2479 2480 ``password=on|off`` 2481 Require that password based authentication is used for client 2482 connections. 2483 2484 The password must be set separately using the ``set_password`` 2485 command in the :ref:`QEMU monitor`. The 2486 syntax to change your password is: 2487 ``set_password <protocol> <password>`` where <protocol> could be 2488 either "vnc" or "spice". 2489 2490 If you would like to change <protocol> password expiration, you 2491 should use ``expire_password <protocol> <expiration-time>`` 2492 where expiration time could be one of the following options: 2493 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2494 make password expire in 60 seconds, or 1335196800 to make 2495 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2496 this date and time). 2497 2498 You can also use keywords "now" or "never" for the expiration 2499 time to allow <protocol> password to expire immediately or never 2500 expire. 2501 2502 ``password-secret=<secret-id>`` 2503 Require that password based authentication is used for client 2504 connections, using the password provided by the ``secret`` 2505 object identified by ``secret-id``. 2506 2507 ``tls-creds=ID`` 2508 Provides the ID of a set of TLS credentials to use to secure the 2509 VNC server. They will apply to both the normal VNC server socket 2510 and the websocket socket (if enabled). Setting TLS credentials 2511 will cause the VNC server socket to enable the VeNCrypt auth 2512 mechanism. The credentials should have been previously created 2513 using the ``-object tls-creds`` argument. 2514 2515 ``tls-authz=ID`` 2516 Provides the ID of the QAuthZ authorization object against which 2517 the client's x509 distinguished name will validated. This object 2518 is only resolved at time of use, so can be deleted and recreated 2519 on the fly while the VNC server is active. If missing, it will 2520 default to denying access. 2521 2522 ``sasl=on|off`` 2523 Require that the client use SASL to authenticate with the VNC 2524 server. The exact choice of authentication method used is 2525 controlled from the system / user's SASL configuration file for 2526 the 'qemu' service. This is typically found in 2527 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2528 an environment variable SASL\_CONF\_PATH can be used to make it 2529 search alternate locations for the service config. While some 2530 SASL auth methods can also provide data encryption (eg GSSAPI), 2531 it is recommended that SASL always be combined with the 'tls' 2532 and 'x509' settings to enable use of SSL and server 2533 certificates. This ensures a data encryption preventing 2534 compromise of authentication credentials. See the 2535 :ref:`VNC security` section in the System Emulation Users Guide 2536 for details on using SASL authentication. 2537 2538 ``sasl-authz=ID`` 2539 Provides the ID of the QAuthZ authorization object against which 2540 the client's SASL username will validated. This object is only 2541 resolved at time of use, so can be deleted and recreated on the 2542 fly while the VNC server is active. If missing, it will default 2543 to denying access. 2544 2545 ``acl=on|off`` 2546 Legacy method for enabling authorization of clients against the 2547 x509 distinguished name and SASL username. It results in the 2548 creation of two ``authz-list`` objects with IDs of 2549 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2550 objects must be configured with the HMP ACL commands. 2551 2552 This option is deprecated and should no longer be used. The new 2553 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2554 2555 ``lossy=on|off`` 2556 Enable lossy compression methods (gradient, JPEG, ...). If this 2557 option is set, VNC client may receive lossy framebuffer updates 2558 depending on its encoding settings. Enabling this option can 2559 save a lot of bandwidth at the expense of quality. 2560 2561 ``non-adaptive=on|off`` 2562 Disable adaptive encodings. Adaptive encodings are enabled by 2563 default. An adaptive encoding will try to detect frequently 2564 updated screen regions, and send updates in these regions using 2565 a lossy encoding (like JPEG). This can be really helpful to save 2566 bandwidth when playing videos. Disabling adaptive encodings 2567 restores the original static behavior of encodings like Tight. 2568 2569 ``share=[allow-exclusive|force-shared|ignore]`` 2570 Set display sharing policy. 'allow-exclusive' allows clients to 2571 ask for exclusive access. As suggested by the rfb spec this is 2572 implemented by dropping other connections. Connecting multiple 2573 clients in parallel requires all clients asking for a shared 2574 session (vncviewer: -shared switch). This is the default. 2575 'force-shared' disables exclusive client access. Useful for 2576 shared desktop sessions, where you don't want someone forgetting 2577 specify -shared disconnect everybody else. 'ignore' completely 2578 ignores the shared flag and allows everybody connect 2579 unconditionally. Doesn't conform to the rfb spec but is 2580 traditional QEMU behavior. 2581 2582 ``key-delay-ms`` 2583 Set keyboard delay, for key down and key up events, in 2584 milliseconds. Default is 10. Keyboards are low-bandwidth 2585 devices, so this slowdown can help the device and guest to keep 2586 up and not lose events in case events are arriving in bulk. 2587 Possible causes for the latter are flaky network connections, or 2588 scripts for automated testing. 2589 2590 ``audiodev=audiodev`` 2591 Use the specified audiodev when the VNC client requests audio 2592 transmission. When not using an -audiodev argument, this option 2593 must be omitted, otherwise is must be present and specify a 2594 valid audiodev. 2595 2596 ``power-control=on|off`` 2597 Permit the remote client to issue shutdown, reboot or reset power 2598 control requests. 2599ERST 2600 2601ARCHHEADING(, QEMU_ARCH_I386) 2602 2603ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2604 2605DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2606 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2607 QEMU_ARCH_I386) 2608SRST 2609``-win2k-hack`` 2610 Use it when installing Windows 2000 to avoid a disk full bug. After 2611 Windows 2000 is installed, you no longer need this option (this 2612 option slows down the IDE transfers). Synonym of ``-global 2613 ide-device.win2k-install-hack=on``. 2614ERST 2615 2616DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2617 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2618 QEMU_ARCH_I386) 2619SRST 2620``-no-fd-bootchk`` 2621 Disable boot signature checking for floppy disks in BIOS. May be 2622 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2623ERST 2624 2625DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2626 "-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" 2627 " ACPI table description\n", QEMU_ARCH_I386) 2628SRST 2629``-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]...]`` 2630 Add ACPI table with specified header fields and context from 2631 specified files. For file=, take whole ACPI table from the specified 2632 files, including all ACPI headers (possible overridden by other 2633 options). For data=, only data portion of the table is used, all 2634 header information is specified in the command line. If a SLIC table 2635 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2636 fields will override the same in the RSDT and the FADT (a.k.a. 2637 FACP), in order to ensure the field matches required by the 2638 Microsoft SLIC spec and the ACPI spec. 2639ERST 2640 2641DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2642 "-smbios file=binary\n" 2643 " load SMBIOS entry from binary file\n" 2644 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2645 " [,uefi=on|off]\n" 2646 " specify SMBIOS type 0 fields\n" 2647 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2648 " [,uuid=uuid][,sku=str][,family=str]\n" 2649 " specify SMBIOS type 1 fields\n" 2650 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2651 " [,asset=str][,location=str]\n" 2652 " specify SMBIOS type 2 fields\n" 2653 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2654 " [,sku=str]\n" 2655 " specify SMBIOS type 3 fields\n" 2656 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2657 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2658 " [,processor-family=%d][,processor-id=%d]\n" 2659 " specify SMBIOS type 4 fields\n" 2660 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2661 " specify SMBIOS type 8 fields\n" 2662 "-smbios type=11[,value=str][,path=filename]\n" 2663 " specify SMBIOS type 11 fields\n" 2664 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2665 " [,asset=str][,part=str][,speed=%d]\n" 2666 " specify SMBIOS type 17 fields\n" 2667 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2668 " specify SMBIOS type 41 fields\n", 2669 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2670SRST 2671``-smbios file=binary`` 2672 Load SMBIOS entry from binary file. 2673 2674``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2675 Specify SMBIOS type 0 fields 2676 2677``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2678 Specify SMBIOS type 1 fields 2679 2680``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2681 Specify SMBIOS type 2 fields 2682 2683``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2684 Specify SMBIOS type 3 fields 2685 2686``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2687 Specify SMBIOS type 4 fields 2688 2689``-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]`` 2690 Specify SMBIOS type 9 fields 2691 2692``-smbios type=11[,value=str][,path=filename]`` 2693 Specify SMBIOS type 11 fields 2694 2695 This argument can be repeated multiple times, and values are added in the order they are parsed. 2696 Applications intending to use OEM strings data are encouraged to use their application name as 2697 a prefix for the value string. This facilitates passing information for multiple applications 2698 concurrently. 2699 2700 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2701 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2702 2703 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2704 the SMBIOS table in the order in which they appear. 2705 2706 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2707 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2708 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2709 data set, for example, by specifying the serial ID of a block device. 2710 2711 An example passing three strings is 2712 2713 .. parsed-literal:: 2714 2715 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2716 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2717 path=/some/file/with/oemstringsdata.txt 2718 2719 In the guest OS this is visible with the ``dmidecode`` command 2720 2721 .. parsed-literal:: 2722 2723 $ dmidecode -t 11 2724 Handle 0x0E00, DMI type 11, 5 bytes 2725 OEM Strings 2726 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2727 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2728 String 3: myapp:some extra data 2729 2730 2731``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2732 Specify SMBIOS type 17 fields 2733 2734``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2735 Specify SMBIOS type 41 fields 2736 2737 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2738 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2739 position on the PCI bus. 2740 2741 Here is an example of use: 2742 2743 .. parsed-literal:: 2744 2745 -netdev user,id=internet \\ 2746 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2747 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2748 2749 In the guest OS, the device should then appear as ``eno1``: 2750 2751 ..parsed-literal:: 2752 2753 $ ip -brief l 2754 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2755 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2756 2757 Currently, the PCI device has to be attached to the root bus. 2758 2759ERST 2760 2761DEFHEADING() 2762 2763DEFHEADING(Network options:) 2764 2765DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2766#ifdef CONFIG_SLIRP 2767 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2768 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2769 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2770 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2771 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2772#ifndef _WIN32 2773 "[,smb=dir[,smbserver=addr]]\n" 2774#endif 2775 " configure a user mode network backend with ID 'str',\n" 2776 " its DHCP server and optional services\n" 2777#endif 2778#ifdef _WIN32 2779 "-netdev tap,id=str,ifname=name\n" 2780 " configure a host TAP network backend with ID 'str'\n" 2781#else 2782 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2783 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2784 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2785 " [,poll-us=n]\n" 2786 " configure a host TAP network backend with ID 'str'\n" 2787 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2788 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2789 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2790 " to deconfigure it\n" 2791 " use '[down]script=no' to disable script execution\n" 2792 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2793 " configure it\n" 2794 " use 'fd=h' to connect to an already opened TAP interface\n" 2795 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2796 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2797 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2798 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2799 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2800 " use vhost=on to enable experimental in kernel accelerator\n" 2801 " (only has effect for virtio guests which use MSIX)\n" 2802 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2803 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2804 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2805 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2806 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2807 " spent on busy polling for vhost net\n" 2808 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2809 " configure a host TAP network backend with ID 'str' that is\n" 2810 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2811 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2812#endif 2813#ifdef __linux__ 2814 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2815 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2816 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2817 " [,rxcookie=rxcookie][,offset=offset]\n" 2818 " configure a network backend with ID 'str' connected to\n" 2819 " an Ethernet over L2TPv3 pseudowire.\n" 2820 " Linux kernel 3.3+ as well as most routers can talk\n" 2821 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2822 " VM to a router and even VM to Host. It is a nearly-universal\n" 2823 " standard (RFC3931). Note - this implementation uses static\n" 2824 " pre-configured tunnels (same as the Linux kernel).\n" 2825 " use 'src=' to specify source address\n" 2826 " use 'dst=' to specify destination address\n" 2827 " use 'udp=on' to specify udp encapsulation\n" 2828 " use 'srcport=' to specify source udp port\n" 2829 " use 'dstport=' to specify destination udp port\n" 2830 " use 'ipv6=on' to force v6\n" 2831 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2832 " well as a weak security measure\n" 2833 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2834 " use 'txcookie=0x012345678' to specify a txcookie\n" 2835 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2836 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2837 " use 'pincounter=on' to work around broken counter handling in peer\n" 2838 " use 'offset=X' to add an extra offset between header and data\n" 2839#endif 2840 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2841 " configure a network backend to connect to another network\n" 2842 " using a socket connection\n" 2843 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2844 " configure a network backend to connect to a multicast maddr and port\n" 2845 " use 'localaddr=addr' to specify the host address to send packets from\n" 2846 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2847 " configure a network backend to connect to another network\n" 2848 " using an UDP tunnel\n" 2849 "-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-ms=milliseconds]\n" 2850 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect-ms=milliseconds]\n" 2851 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect-ms=milliseconds]\n" 2852 " configure a network backend to connect to another network\n" 2853 " using a socket connection in stream mode.\n" 2854 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2855 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2856 " configure a network backend to connect to a multicast maddr and port\n" 2857 " use ``local.host=addr`` to specify the host address to send packets from\n" 2858 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2859 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2860 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2861 " configure a network backend to connect to another network\n" 2862 " using an UDP tunnel\n" 2863#ifdef CONFIG_VDE 2864 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2865 " configure a network backend to connect to port 'n' of a vde switch\n" 2866 " running on host and listening for incoming connections on 'socketpath'.\n" 2867 " Use group 'groupname' and mode 'octalmode' to change default\n" 2868 " ownership and permissions for communication port.\n" 2869#endif 2870#ifdef CONFIG_NETMAP 2871 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2872 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2873 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2874 " netmap device, defaults to '/dev/netmap')\n" 2875#endif 2876#ifdef CONFIG_AF_XDP 2877 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2878 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2879 " attach to the existing network interface 'name' with AF_XDP socket\n" 2880 " use 'mode=MODE' to specify an XDP program attach mode\n" 2881 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2882 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2883 " with inhibit=on,\n" 2884 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2885 " added to a socket map in XDP program. One socket per queue.\n" 2886 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2887 " use 'start-queue=m' to specify the first queue that should be used\n" 2888#endif 2889#ifdef CONFIG_POSIX 2890 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2891 " configure a vhost-user network, backed by a chardev 'dev'\n" 2892#endif 2893#ifdef __linux__ 2894 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2895 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2896 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2897 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2898#endif 2899#ifdef CONFIG_VMNET 2900 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2901 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2902 " configure a vmnet network backend in host mode with ID 'str',\n" 2903 " isolate this interface from others with 'isolated',\n" 2904 " configure the address range and choose a subnet mask,\n" 2905 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2906 " vmnet-host interfaces within this isolated network\n" 2907 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2908 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2909 " configure a vmnet network backend in shared mode with ID 'str',\n" 2910 " configure the address range and choose a subnet mask,\n" 2911 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2912 " isolate this interface from others with 'isolated'\n" 2913 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2914 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2915 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2916 " isolate this interface from others with 'isolated'\n" 2917#endif 2918 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2919 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2920DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2921 "-nic [tap|bridge|" 2922#ifdef CONFIG_SLIRP 2923 "user|" 2924#endif 2925#ifdef __linux__ 2926 "l2tpv3|" 2927#endif 2928#ifdef CONFIG_VDE 2929 "vde|" 2930#endif 2931#ifdef CONFIG_NETMAP 2932 "netmap|" 2933#endif 2934#ifdef CONFIG_AF_XDP 2935 "af-xdp|" 2936#endif 2937#ifdef CONFIG_POSIX 2938 "vhost-user|" 2939#endif 2940#ifdef CONFIG_VMNET 2941 "vmnet-host|vmnet-shared|vmnet-bridged|" 2942#endif 2943 "socket][,option][,...][mac=macaddr]\n" 2944 " initialize an on-board / default host NIC (using MAC address\n" 2945 " macaddr) and connect it to the given host network backend\n" 2946 "-nic none use it alone to have zero network devices (the default is to\n" 2947 " provided a 'user' network connection)\n", 2948 QEMU_ARCH_ALL) 2949DEF("net", HAS_ARG, QEMU_OPTION_net, 2950 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2951 " configure or create an on-board (or machine default) NIC and\n" 2952 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2953 "-net [" 2954#ifdef CONFIG_SLIRP 2955 "user|" 2956#endif 2957 "tap|" 2958 "bridge|" 2959#ifdef CONFIG_VDE 2960 "vde|" 2961#endif 2962#ifdef CONFIG_NETMAP 2963 "netmap|" 2964#endif 2965#ifdef CONFIG_AF_XDP 2966 "af-xdp|" 2967#endif 2968#ifdef CONFIG_VMNET 2969 "vmnet-host|vmnet-shared|vmnet-bridged|" 2970#endif 2971 "socket][,option][,option][,...]\n" 2972 " old way to initialize a host network interface\n" 2973 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2974SRST 2975``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2976 This option is a shortcut for configuring both the on-board 2977 (default) guest NIC hardware and the host network backend in one go. 2978 The host backend options are the same as with the corresponding 2979 ``-netdev`` options below. The guest NIC model can be set with 2980 ``model=modelname``. Use ``model=help`` to list the available device 2981 types. The hardware MAC address can be set with ``mac=macaddr``. 2982 2983 The following two example do exactly the same, to show how ``-nic`` 2984 can be used to shorten the command line length: 2985 2986 .. parsed-literal:: 2987 2988 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2989 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2990 2991``-nic none`` 2992 Indicate that no network devices should be configured. It is used to 2993 override the default configuration (default NIC with "user" host 2994 network backend) which is activated if no other networking options 2995 are provided. 2996 2997``-netdev user,id=id[,option][,option][,...]`` 2998 Configure user mode host network backend which requires no 2999 administrator privilege to run. Valid options are: 3000 3001 ``id=id`` 3002 Assign symbolic name for use in monitor commands. 3003 3004 ``ipv4=on|off and ipv6=on|off`` 3005 Specify that either IPv4 or IPv6 must be enabled. If neither is 3006 specified both protocols are enabled. 3007 3008 ``net=addr[/mask]`` 3009 Set IP network address the guest will see. Optionally specify 3010 the netmask, either in the form a.b.c.d or as number of valid 3011 top-most bits. Default is 10.0.2.0/24. 3012 3013 ``host=addr`` 3014 Specify the guest-visible address of the host. Default is the 3015 2nd IP in the guest network, i.e. x.x.x.2. 3016 3017 ``ipv6-net=addr[/int]`` 3018 Set IPv6 network address the guest will see (default is 3019 fec0::/64). The network prefix is given in the usual hexadecimal 3020 IPv6 address notation. The prefix size is optional, and is given 3021 as the number of valid top-most bits (default is 64). 3022 3023 ``ipv6-host=addr`` 3024 Specify the guest-visible IPv6 address of the host. Default is 3025 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3026 3027 ``restrict=on|off`` 3028 If this option is enabled, the guest will be isolated, i.e. it 3029 will not be able to contact the host and no guest IP packets 3030 will be routed over the host to the outside. This option does 3031 not affect any explicitly set forwarding rules. 3032 3033 ``hostname=name`` 3034 Specifies the client hostname reported by the built-in DHCP 3035 server. 3036 3037 ``dhcpstart=addr`` 3038 Specify the first of the 16 IPs the built-in DHCP server can 3039 assign. Default is the 15th to 31st IP in the guest network, 3040 i.e. x.x.x.15 to x.x.x.31. 3041 3042 ``dns=addr`` 3043 Specify the guest-visible address of the virtual nameserver. The 3044 address must be different from the host address. Default is the 3045 3rd IP in the guest network, i.e. x.x.x.3. 3046 3047 ``ipv6-dns=addr`` 3048 Specify the guest-visible address of the IPv6 virtual 3049 nameserver. The address must be different from the host address. 3050 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3051 3052 ``dnssearch=domain`` 3053 Provides an entry for the domain-search list sent by the 3054 built-in DHCP server. More than one domain suffix can be 3055 transmitted by specifying this option multiple times. If 3056 supported, this will cause the guest to automatically try to 3057 append the given domain suffix(es) in case a domain name can not 3058 be resolved. 3059 3060 Example: 3061 3062 .. parsed-literal:: 3063 3064 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3065 3066 ``domainname=domain`` 3067 Specifies the client domain name reported by the built-in DHCP 3068 server. 3069 3070 ``tftp=dir`` 3071 When using the user mode network stack, activate a built-in TFTP 3072 server. The files in dir will be exposed as the root of a TFTP 3073 server. The TFTP client on the guest must be configured in 3074 binary mode (use the command ``bin`` of the Unix TFTP client). 3075 The built-in TFTP server is read-only; it does not implement any 3076 command for writing files. QEMU will not write to this directory. 3077 3078 ``tftp-server-name=name`` 3079 In BOOTP reply, broadcast name as the "TFTP server name" 3080 (RFC2132 option 66). This can be used to advise the guest to 3081 load boot files or configurations from a different server than 3082 the host address. 3083 3084 ``bootfile=file`` 3085 When using the user mode network stack, broadcast file as the 3086 BOOTP filename. In conjunction with ``tftp``, this can be used 3087 to network boot a guest from a local directory. 3088 3089 Example (using pxelinux): 3090 3091 .. parsed-literal:: 3092 3093 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3094 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3095 3096 ``smb=dir[,smbserver=addr]`` 3097 When using the user mode network stack, activate a built-in SMB 3098 server so that Windows OSes can access to the host files in 3099 ``dir`` transparently. The IP address of the SMB server can be 3100 set to addr. By default the 4th IP in the guest network is used, 3101 i.e. x.x.x.4. 3102 3103 In the guest Windows OS, the line: 3104 3105 :: 3106 3107 10.0.2.4 smbserver 3108 3109 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3110 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3111 NT/2000). 3112 3113 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3114 3115 Note that a SAMBA server must be installed on the host OS. 3116 3117 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3118 Redirect incoming TCP or UDP connections to the host port 3119 hostport to the guest IP address guestaddr on guest port 3120 guestport. If guestaddr is not specified, its value is x.x.x.15 3121 (default first address given by the built-in DHCP server). By 3122 specifying hostaddr, the rule can be bound to a specific host 3123 interface. If no connection type is set, TCP is used. This 3124 option can be given multiple times. 3125 3126 For example, to redirect host X11 connection from screen 1 to 3127 guest screen 0, use the following: 3128 3129 .. parsed-literal:: 3130 3131 # on the host 3132 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3133 # this host xterm should open in the guest X11 server 3134 xterm -display :1 3135 3136 To redirect telnet connections from host port 5555 to telnet 3137 port on the guest, use the following: 3138 3139 .. parsed-literal:: 3140 3141 # on the host 3142 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3143 telnet localhost 5555 3144 3145 Then when you use on the host ``telnet localhost 5555``, you 3146 connect to the guest telnet server. 3147 3148 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3149 Forward guest TCP connections to the IP address server on port 3150 port to the character device dev or to a program executed by 3151 cmd:command which gets spawned for each connection. This option 3152 can be given multiple times. 3153 3154 You can either use a chardev directly and have that one used 3155 throughout QEMU's lifetime, like in the following example: 3156 3157 .. parsed-literal:: 3158 3159 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3160 # the guest accesses it 3161 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3162 3163 Or you can execute a command on every TCP connection established 3164 by the guest, so that QEMU behaves similar to an inetd process 3165 for that virtual server: 3166 3167 .. parsed-literal:: 3168 3169 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3170 # and connect the TCP stream to its stdin/stdout 3171 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3172 3173``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3174 Configure a host TAP network backend with ID id. 3175 3176 Use the network script file to configure it and the network script 3177 dfile to deconfigure it. If name is not provided, the OS 3178 automatically provides one. The default network configure script is 3179 ``/etc/qemu-ifup`` and the default network deconfigure script is 3180 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3181 disable script execution. 3182 3183 If running QEMU as an unprivileged user, use the network helper 3184 to configure the TAP interface and attach it to the bridge. 3185 The default network helper executable is 3186 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3187 ``br0``. 3188 3189 ``fd``\ =h can be used to specify the handle of an already opened 3190 host TAP interface. 3191 3192 Examples: 3193 3194 .. parsed-literal:: 3195 3196 #launch a QEMU instance with the default network script 3197 |qemu_system| linux.img -nic tap 3198 3199 .. parsed-literal:: 3200 3201 #launch a QEMU instance with two NICs, each one connected 3202 #to a TAP device 3203 |qemu_system| linux.img \\ 3204 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3205 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3206 3207 .. parsed-literal:: 3208 3209 #launch a QEMU instance with the default network helper to 3210 #connect a TAP device to bridge br0 3211 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3212 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3213 3214``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3215 Connect a host TAP network interface to a host bridge device. 3216 3217 Use the network helper helper to configure the TAP interface and 3218 attach it to the bridge. The default network helper executable is 3219 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3220 ``br0``. 3221 3222 Examples: 3223 3224 .. parsed-literal:: 3225 3226 #launch a QEMU instance with the default network helper to 3227 #connect a TAP device to bridge br0 3228 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3229 3230 .. parsed-literal:: 3231 3232 #launch a QEMU instance with the default network helper to 3233 #connect a TAP device to bridge qemubr0 3234 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3235 3236``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3237 This host network backend can be used to connect the guest's network 3238 to another QEMU virtual machine using a TCP socket connection. If 3239 ``listen`` is specified, QEMU waits for incoming connections on port 3240 (host is optional). ``connect`` is used to connect to another QEMU 3241 instance using the ``listen`` option. ``fd``\ =h specifies an 3242 already opened TCP socket. 3243 3244 Example: 3245 3246 .. parsed-literal:: 3247 3248 # launch a first QEMU instance 3249 |qemu_system| linux.img \\ 3250 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3251 -netdev socket,id=n1,listen=:1234 3252 # connect the network of this instance to the network of the first instance 3253 |qemu_system| linux.img \\ 3254 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3255 -netdev socket,id=n2,connect=127.0.0.1:1234 3256 3257``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3258 Configure a socket host network backend to share the guest's network 3259 traffic with another QEMU virtual machines using a UDP multicast 3260 socket, effectively making a bus for every QEMU with same multicast 3261 address maddr and port. NOTES: 3262 3263 1. Several QEMU can be running on different hosts and share same bus 3264 (assuming correct multicast setup for these hosts). 3265 3266 2. mcast support is compatible with User Mode Linux (argument 3267 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3268 3269 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3270 3271 Example: 3272 3273 .. parsed-literal:: 3274 3275 # launch one QEMU instance 3276 |qemu_system| linux.img \\ 3277 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3278 -netdev socket,id=n1,mcast=230.0.0.1:1234 3279 # launch another QEMU instance on same "bus" 3280 |qemu_system| linux.img \\ 3281 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3282 -netdev socket,id=n2,mcast=230.0.0.1:1234 3283 # launch yet another QEMU instance on same "bus" 3284 |qemu_system| linux.img \\ 3285 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3286 -netdev socket,id=n3,mcast=230.0.0.1:1234 3287 3288 Example (User Mode Linux compat.): 3289 3290 .. parsed-literal:: 3291 3292 # launch QEMU instance (note mcast address selected is UML's default) 3293 |qemu_system| linux.img \\ 3294 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3295 -netdev socket,id=n1,mcast=239.192.168.1:1102 3296 # launch UML 3297 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3298 3299 Example (send packets from host's 1.2.3.4): 3300 3301 .. parsed-literal:: 3302 3303 |qemu_system| linux.img \\ 3304 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3305 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3306 3307``-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-ms=milliseconds]`` 3308 Configure a network backend to connect to another QEMU virtual machine or a proxy using a TCP/IP socket. 3309 3310 ``server=on|off`` 3311 if ``on`` create a server socket 3312 3313 ``addr.host=host,addr.port=port`` 3314 socket address to listen on (server=on) or connect to (server=off) 3315 3316 ``to=maxport`` 3317 if present, this is range of possible addresses, with port between ``port`` and ``maxport``. 3318 3319 ``numeric=on|off`` 3320 if ``on`` ``host`` and ``port`` are guaranteed to be numeric, otherwise a name resolution should be attempted (default: ``off``) 3321 3322 ``keep-alive=on|off`` 3323 enable keep-alive when connecting to this socket. Not supported for passive sockets. 3324 3325 ``mptcp=on|off`` 3326 enable multipath TCP 3327 3328 ``ipv4=on|off`` 3329 whether to accept IPv4 addresses, default to try both IPv4 and IPv6 3330 3331 ``ipv6=on|off`` 3332 whether to accept IPv6 addresses, default to try both IPv4 and IPv6 3333 3334 ``reconnect-ms=milliseconds`` 3335 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of milliseconds. 3336 Setting this to zero disables this function. (default: 0) 3337 3338 Example (two guests connected using a TCP/IP socket): 3339 3340 .. parsed-literal:: 3341 3342 # first VM 3343 |qemu_system| linux.img \\ 3344 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3345 -netdev stream,id=net0,server=on,addr.type=inet,addr.host=localhost,addr.port=1234 3346 # second VM 3347 |qemu_system| linux.img \\ 3348 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3349 -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234,reconnect-ms=5000 3350 3351``-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect-ms=milliseconds]`` 3352 Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented unix domain socket. 3353 3354 ``server=on|off`` 3355 if ``on`` create a server socket 3356 3357 ``addr.path=path`` 3358 filesystem path to use 3359 3360 ``abstract=on|off`` 3361 if ``on``, this is a Linux abstract socket address. 3362 3363 ``tight=on|off`` 3364 if false, pad an abstract socket address with enough null bytes to make it fill struct sockaddr_un member sun_path. 3365 3366 ``reconnect-ms=milliseconds`` 3367 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of milliseconds. 3368 Setting this to zero disables this function. (default: 0) 3369 3370 Example (using passt as a replacement of -netdev user): 3371 3372 .. parsed-literal:: 3373 3374 # start passt server as a non privileged user 3375 passt 3376 UNIX domain socket bound at /tmp/passt_1.socket 3377 # start QEMU to connect to passt 3378 |qemu_system| linux.img \\ 3379 -device virtio-net,netdev=net0 \\ 3380 -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/passt_1.socket 3381 3382 Example (two guests connected using a stream oriented unix domain socket): 3383 3384 .. parsed-literal:: 3385 3386 # first VM 3387 |qemu_system| linux.img \\ 3388 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3389 netdev stream,id=net0,server=on,addr.type=unix,addr.path=/tmp/qemu0 3390 # second VM 3391 |qemu_system| linux.img \\ 3392 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3393 -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/qemu0,reconnect-ms=5000 3394 3395``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect-ms=milliseconds]`` 3396 Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented socket file descriptor. 3397 3398 ``server=on|off`` 3399 if ``on`` create a server socket 3400 3401 ``addr.str=file-descriptor`` 3402 file descriptor number to use as a socket 3403 3404 ``reconnect-ms=milliseconds`` 3405 for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of milliseconds. 3406 Setting this to zero disables this function. (default: 0) 3407 3408``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]`` 3409 Configure a network backend to connect to a multicast address. 3410 3411 ``remote.host=maddr,remote.port=port`` 3412 multicast address 3413 3414 ``local.host=addr`` 3415 specify the host address to send packets from 3416 3417 Example: 3418 3419 .. parsed-literal:: 3420 3421 # launch one QEMU instance 3422 |qemu_system| linux.img \\ 3423 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3424 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3425 # launch another QEMU instance on same "bus" 3426 |qemu_system| linux.img \\ 3427 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3428 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3429 # launch yet another QEMU instance on same "bus" 3430 |qemu_system| linux.img \\ 3431 -device virtio-net,netdev=net0,mac=52:54:00:12:34:58 \\ 3432 -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234 3433 3434``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]`` 3435 Configure a network backend to connect to a multicast address using a UDP socket file descriptor. 3436 3437 ``remote.host=maddr,remote.port=port`` 3438 multicast address 3439 3440 ``local.str=file-descriptor`` 3441 File descriptor to use to send packets 3442 3443``-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]`` 3444 Configure a network backend to connect to another QEMU virtual 3445 machine or a proxy using a datagram oriented unix domain socket. 3446 3447 ``local.host=addr,local.port=port`` 3448 IP address to use to send the packets from 3449 3450 ``remote.host=addr,remote.port=port`` 3451 Destination IP address 3452 3453 Example (two guests connected using an UDP/IP socket): 3454 3455 .. parsed-literal:: 3456 3457 # first VM 3458 |qemu_system| linux.img \\ 3459 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3460 -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1234,remote.type=inet,remote.host=localhost,remote.port=1235 3461 # second VM 3462 |qemu_system| linux.img \\ 3463 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3464 -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1235,remote.type=inet,remote.host=localhost,remote.port=1234 3465 3466``-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]`` 3467 Configure a network backend to connect to another QEMU virtual 3468 machine or a proxy using a datagram oriented unix socket. 3469 3470 ``local.path=path`` 3471 filesystem path to use to bind the socket 3472 3473 ``remote.path=path`` 3474 filesystem path to use as a destination (see sendto(2)) 3475 3476 Example (two guests connected using an UDP/UNIX socket): 3477 3478 .. parsed-literal:: 3479 3480 # first VM 3481 |qemu_system| linux.img \\ 3482 -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\ 3483 -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu0,remote.type=unix,remote.path=/tmp/qemu1 3484 # second VM 3485 |qemu_system| linux.img \\ 3486 -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\ 3487 -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu1,remote.type=unix,remote.path=/tmp/qemu0 3488 3489``-netdev dgram,id=str,local.type=fd,local.str=file-descriptor`` 3490 Configure a network backend to connect to another QEMU virtual 3491 machine or a proxy using a datagram oriented socket file descriptor. 3492 3493 ``local.str=file-descriptor`` 3494 File descriptor to use to send packets 3495 3496``-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]`` 3497 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3498 is a popular protocol to transport Ethernet (and other Layer 2) data 3499 frames between two systems. It is present in routers, firewalls and 3500 the Linux kernel (from version 3.3 onwards). 3501 3502 This transport allows a VM to communicate to another VM, router or 3503 firewall directly. 3504 3505 ``src=srcaddr`` 3506 source address (mandatory) 3507 3508 ``dst=dstaddr`` 3509 destination address (mandatory) 3510 3511 ``udp=on`` 3512 select udp encapsulation (default is ip). 3513 3514 ``srcport=srcport`` 3515 source udp port. 3516 3517 ``dstport=dstport`` 3518 destination udp port. 3519 3520 ``ipv6=on`` 3521 force v6, otherwise defaults to v4. 3522 3523 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3524 Cookies are a weak form of security in the l2tpv3 specification. 3525 Their function is mostly to prevent misconfiguration. By default 3526 they are 32 bit. 3527 3528 ``cookie64=on`` 3529 Set cookie size to 64 bit instead of the default 32 3530 3531 ``counter=off`` 3532 Force a 'cut-down' L2TPv3 with no counter as in 3533 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3534 3535 ``pincounter=on`` 3536 Work around broken counter handling in peer. This may also help 3537 on networks which have packet reorder. 3538 3539 ``offset=offset`` 3540 Add an extra offset between header and data 3541 3542 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3543 the bridge br-lan on the remote Linux host 1.2.3.4: 3544 3545 .. parsed-literal:: 3546 3547 # Setup tunnel on linux host using raw ip as encapsulation 3548 # on 1.2.3.4 3549 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3550 encap udp udp_sport 16384 udp_dport 16384 3551 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3552 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3553 ifconfig vmtunnel0 mtu 1500 3554 ifconfig vmtunnel0 up 3555 brctl addif br-lan vmtunnel0 3556 3557 3558 # on 4.3.2.1 3559 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3560 3561 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3562 -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 3563 3564``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3565 Configure VDE backend to connect to PORT n of a vde switch running 3566 on host and listening for incoming connections on socketpath. Use 3567 GROUP groupname and MODE octalmode to change default ownership and 3568 permissions for communication port. This option is only available if 3569 QEMU has been compiled with vde support enabled. 3570 3571 Example: 3572 3573 .. parsed-literal:: 3574 3575 # launch vde switch 3576 vde_switch -F -sock /tmp/myswitch 3577 # launch QEMU instance 3578 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3579 3580``-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]`` 3581 Configure AF_XDP backend to connect to a network interface 'name' 3582 using AF_XDP socket. A specific program attach mode for a default 3583 XDP program can be forced with 'mode', defaults to best-effort, 3584 where the likely most performant mode will be in use. Number of queues 3585 'n' should generally match the number or queues in the interface, 3586 defaults to 1. Traffic arriving on non-configured device queues will 3587 not be delivered to the network backend. 3588 3589 .. parsed-literal:: 3590 3591 # set number of queues to 4 3592 ethtool -L eth0 combined 4 3593 # launch QEMU instance 3594 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3595 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3596 3597 'start-queue' option can be specified if a particular range of queues 3598 [m, m + n] should be in use. For example, this is may be necessary in 3599 order to use certain NICs in native mode. Kernel allows the driver to 3600 create a separate set of XDP queues on top of regular ones, and only 3601 these queues can be used for AF_XDP sockets. NICs that work this way 3602 may also require an additional traffic redirection with ethtool to these 3603 special queues. 3604 3605 .. parsed-literal:: 3606 3607 # set number of queues to 1 3608 ethtool -L eth0 combined 1 3609 # redirect all the traffic to the second queue (id: 1) 3610 # note: drivers may require non-empty key/mask pair. 3611 ethtool -N eth0 flow-type ether \\ 3612 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3613 ethtool -N eth0 flow-type ether \\ 3614 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3615 # launch QEMU instance 3616 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3617 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3618 3619 XDP program can also be loaded externally. In this case 'inhibit' option 3620 should be set to 'on' and 'sock-fds' provided with file descriptors for 3621 already open but not bound XDP sockets already added to a socket map for 3622 corresponding queues. One socket per queue. 3623 3624 .. parsed-literal:: 3625 3626 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3627 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3628 3629``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3630 Establish a vhost-user netdev, backed by a chardev id. The chardev 3631 should be a unix domain socket backed one. The vhost-user uses a 3632 specifically defined protocol to pass vhost ioctl replacement 3633 messages to an application on the other end of the socket. On 3634 non-MSIX guests, the feature can be forced with vhostforce. Use 3635 'queues=n' to specify the number of queues to be created for 3636 multiqueue vhost-user. 3637 3638 Example: 3639 3640 :: 3641 3642 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3643 -numa node,memdev=mem \ 3644 -chardev socket,id=chr0,path=/path/to/socket \ 3645 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3646 -device virtio-net-pci,netdev=net0 3647 3648``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3649 Establish a vhost-vdpa netdev. 3650 3651 vDPA device is a device that uses a datapath which complies with 3652 the virtio specifications with a vendor specific control path. 3653 vDPA devices can be both physically located on the hardware or 3654 emulated by software. 3655 3656``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3657 Create a hub port on the emulated hub with ID hubid. 3658 3659 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3660 instead of a single netdev. Alternatively, you can also connect the 3661 hubport to another netdev with ID nd by using the ``netdev=nd`` 3662 option. 3663 3664``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3665 Legacy option to configure or create an on-board (or machine 3666 default) Network Interface Card(NIC) and connect it either to the 3667 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3668 If model is omitted, then the default NIC model associated with the 3669 machine type is used. Note that the default NIC model may change in 3670 future QEMU releases, so it is highly recommended to always specify 3671 a model. Optionally, the MAC address can be changed to mac, the 3672 device address set to addr (PCI cards only), and a name can be 3673 assigned for use in monitor commands. Optionally, for PCI cards, you 3674 can specify the number v of MSI-X vectors that the card should have; 3675 this option currently only affects virtio cards; set v = 0 to 3676 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3677 created. QEMU can emulate several different models of network card. 3678 Use ``-net nic,model=help`` for a list of available devices for your 3679 target. 3680 3681``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3682 Configure a host network backend (with the options corresponding to 3683 the same ``-netdev`` option) and connect it to the emulated hub 0 3684 (the default hub). Use name to specify the name of the hub port. 3685ERST 3686 3687DEFHEADING() 3688 3689DEFHEADING(Character device options:) 3690 3691DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3692 "-chardev help\n" 3693 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3694 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3695 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect-ms=milliseconds][,mux=on|off]\n" 3696 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3697 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect-ms=milliseconds]\n" 3698 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3699 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3700 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3701 " [,logfile=PATH][,logappend=on|off]\n" 3702 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3703 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3704 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3705 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3706 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3707 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3708#ifdef _WIN32 3709 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3710 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3711#else 3712 "-chardev pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3713 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3714#endif 3715#ifdef CONFIG_BRLAPI 3716 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3717#endif 3718#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3719 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3720 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3721#endif 3722#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3723 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3724#endif 3725#if defined(CONFIG_SPICE) 3726 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3727 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3728#endif 3729 , QEMU_ARCH_ALL 3730) 3731 3732SRST 3733The general form of a character device option is: 3734 3735``-chardev backend,id=id[,mux=on|off][,options]`` 3736 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3737 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3738 ``pty``, ``stdio``, ``braille``, ``parallel``, 3739 ``spicevmc``, ``spiceport``. The specific backend will determine the 3740 applicable options. 3741 3742 Use ``-chardev help`` to print all available chardev backend types. 3743 3744 All devices must have an id, which can be any string up to 127 3745 characters long. It is used to uniquely identify this device in 3746 other command line directives. 3747 3748 A character device may be used in multiplexing mode by multiple 3749 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3750 a "1:N" device, and here the "1" end is your specified chardev 3751 backend, and the "N" end is the various parts of QEMU that can talk 3752 to a chardev. If you create a chardev with ``id=myid`` and 3753 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3754 and you can then configure multiple front ends to use that chardev 3755 ID for their input/output. Up to four different front ends can be 3756 connected to a single multiplexed chardev. (Without multiplexing 3757 enabled, a chardev can only be used by a single front end.) For 3758 instance you could use this to allow a single stdio chardev to be 3759 used by two serial ports and the QEMU monitor: 3760 3761 :: 3762 3763 -chardev stdio,mux=on,id=char0 \ 3764 -mon chardev=char0,mode=readline \ 3765 -serial chardev:char0 \ 3766 -serial chardev:char0 3767 3768 You can have more than one multiplexer in a system configuration; 3769 for instance you could have a TCP port multiplexed between UART 0 3770 and UART 1, and stdio multiplexed between the QEMU monitor and a 3771 parallel port: 3772 3773 :: 3774 3775 -chardev stdio,mux=on,id=char0 \ 3776 -mon chardev=char0,mode=readline \ 3777 -parallel chardev:char0 \ 3778 -chardev tcp,...,mux=on,id=char1 \ 3779 -serial chardev:char1 \ 3780 -serial chardev:char1 3781 3782 When you're using a multiplexed character device, some escape 3783 sequences are interpreted in the input. See the chapter about 3784 :ref:`keys in the character backend multiplexer` in the 3785 System Emulation Users Guide for more details. 3786 3787 Note that some other command line options may implicitly create 3788 multiplexed character backends; for instance ``-serial mon:stdio`` 3789 creates a multiplexed stdio backend connected to the serial port and 3790 the QEMU monitor, and ``-nographic`` also multiplexes the console 3791 and the monitor to stdio. 3792 3793 There is currently no support for multiplexing in the other 3794 direction (where a single QEMU front end takes input and output from 3795 multiple chardevs). 3796 3797 Every backend supports the ``logfile`` option, which supplies the 3798 path to a file to record all data transmitted via the backend. The 3799 ``logappend`` option controls whether the log file will be truncated 3800 or appended to when opened. 3801 3802The available backends are: 3803 3804``-chardev null,id=id`` 3805 A void device. This device will not emit any data, and will drop any 3806 data it receives. The null backend does not take any options. 3807 3808``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect-ms=milliseconds][,tls-creds=id][,tls-authz=id]`` 3809 Create a two-way stream socket, which can be either a TCP or a unix 3810 socket. A unix socket will be created if ``path`` is specified. 3811 Behaviour is undefined if TCP options are specified for a unix 3812 socket. 3813 3814 ``server=on|off`` specifies that the socket shall be a listening socket. 3815 3816 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3817 to connect to a listening socket. 3818 3819 ``telnet=on|off`` specifies that traffic on the socket should interpret 3820 telnet escape sequences. 3821 3822 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3823 communication. 3824 3825 ``reconnect-ms`` sets the timeout for reconnecting on non-server 3826 sockets when the remote end goes away. qemu will delay this many 3827 milliseconds and then attempt to reconnect. Zero disables reconnecting, 3828 and is the default. 3829 3830 ``tls-creds`` requests enablement of the TLS protocol for 3831 encryption, and specifies the id of the TLS credentials to use for 3832 the handshake. The credentials must be previously created with the 3833 ``-object tls-creds`` argument. 3834 3835 ``tls-auth`` provides the ID of the QAuthZ authorization object 3836 against which the client's x509 distinguished name will be 3837 validated. This object is only resolved at time of use, so can be 3838 deleted and recreated on the fly while the chardev server is active. 3839 If missing, it will default to denying access. 3840 3841 TCP and unix socket options are given below: 3842 3843 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3844 ``host`` for a listening socket specifies the local address to 3845 be bound. For a connecting socket species the remote host to 3846 connect to. ``host`` is optional for listening sockets. If not 3847 specified it defaults to ``0.0.0.0``. 3848 3849 ``port`` for a listening socket specifies the local port to be 3850 bound. For a connecting socket specifies the port on the remote 3851 host to connect to. ``port`` can be given as either a port 3852 number or a service name. ``port`` is required. 3853 3854 ``to`` is only relevant to listening sockets. If it is 3855 specified, and ``port`` cannot be bound, QEMU will attempt to 3856 bind to subsequent ports up to and including ``to`` until it 3857 succeeds. ``to`` must be specified as a port number. 3858 3859 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3860 or IPv6 must be used. If neither is specified the socket may 3861 use either protocol. 3862 3863 ``nodelay=on|off`` disables the Nagle algorithm. 3864 3865 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3866 ``path`` specifies the local path of the unix socket. ``path`` 3867 is required. 3868 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3869 rather than the filesystem. Optional, defaults to false. 3870 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3871 rather than the full sun_path length. Optional, defaults to true. 3872 3873``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3874 Sends all traffic from the guest to a remote host over UDP. 3875 3876 ``host`` specifies the remote host to connect to. If not specified 3877 it defaults to ``localhost``. 3878 3879 ``port`` specifies the port on the remote host to connect to. 3880 ``port`` is required. 3881 3882 ``localaddr`` specifies the local address to bind to. If not 3883 specified it defaults to ``0.0.0.0``. 3884 3885 ``localport`` specifies the local port to bind to. If not specified 3886 any available local port will be used. 3887 3888 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3889 If neither is specified the device may use either protocol. 3890 3891``-chardev msmouse,id=id`` 3892 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3893 does not take any options. 3894 3895``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3896 Connect to a QEMU text console. ``vc`` may optionally be given a 3897 specific size. 3898 3899 ``width`` and ``height`` specify the width and height respectively 3900 of the console, in pixels. 3901 3902 ``cols`` and ``rows`` specify that the console be sized to fit a 3903 text console with the given dimensions. 3904 3905``-chardev ringbuf,id=id[,size=size]`` 3906 Create a ring buffer with fixed size ``size``. size must be a power 3907 of two and defaults to ``64K``. 3908 3909``-chardev file,id=id,path=path[,input-path=input-path]`` 3910 Log all traffic received from the guest to a file. 3911 3912 ``path`` specifies the path of the file to be opened. This file will 3913 be created if it does not already exist, and overwritten if it does. 3914 ``path`` is required. 3915 3916 If ``input-path`` is specified, this is the path of a second file 3917 which will be used for input. If ``input-path`` is not specified, 3918 no input will be available from the chardev. 3919 3920 Note that ``input-path`` is not supported on Windows hosts. 3921 3922``-chardev pipe,id=id,path=path`` 3923 Create a two-way connection to the guest. The behaviour differs 3924 slightly between Windows hosts and other hosts: 3925 3926 On Windows, a single duplex pipe will be created at 3927 ``\\.pipe\path``. 3928 3929 On other hosts, 2 pipes will be created called ``path.in`` and 3930 ``path.out``. Data written to ``path.in`` will be received by the 3931 guest. Data written by the guest can be read from ``path.out``. QEMU 3932 will not create these fifos, and requires them to be present. 3933 3934 ``path`` forms part of the pipe path as described above. ``path`` is 3935 required. 3936 3937``-chardev console,id=id`` 3938 Send traffic from the guest to QEMU's standard output. ``console`` 3939 does not take any options. 3940 3941 ``console`` is only available on Windows hosts. 3942 3943``-chardev serial,id=id,path=path`` 3944 Send traffic from the guest to a serial device on the host. 3945 3946 On Unix hosts serial will actually accept any tty device, not only 3947 serial lines. 3948 3949 ``path`` specifies the name of the serial device to open. 3950 3951``-chardev pty,id=id[,path=path]`` 3952 Create a new pseudo-terminal on the host and connect to it. 3953 3954 ``pty`` is not available on Windows hosts. 3955 3956 If ``path`` is specified, QEMU will create a symbolic link at 3957 that location which points to the new PTY device. 3958 3959 This avoids having to make QMP or HMP monitor queries to find out 3960 what the new PTY device path is. 3961 3962 Note that while QEMU will remove the symlink when it exits 3963 gracefully, it will not do so in case of crashes or on certain 3964 startup errors. It is recommended that the user checks and removes 3965 the symlink after QEMU terminates to account for this. 3966 3967``-chardev stdio,id=id[,signal=on|off]`` 3968 Connect to standard input and standard output of the QEMU process. 3969 3970 ``signal`` controls if signals are enabled on the terminal, that 3971 includes exiting QEMU with the key sequence Control-c. This option 3972 is enabled by default, use ``signal=off`` to disable it. 3973 3974``-chardev braille,id=id`` 3975 Connect to a local BrlAPI server. ``braille`` does not take any 3976 options. 3977 3978``-chardev parallel,id=id,path=path`` 3979 \ 3980 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3981 hosts. 3982 3983 Connect to a local parallel port. 3984 3985 ``path`` specifies the path to the parallel port device. ``path`` is 3986 required. 3987 3988``-chardev spicevmc,id=id,debug=debug,name=name`` 3989 ``spicevmc`` is only available when spice support is built in. 3990 3991 ``debug`` debug level for spicevmc 3992 3993 ``name`` name of spice channel to connect to 3994 3995 Connect to a spice virtual machine channel, such as vdiport. 3996 3997``-chardev spiceport,id=id,debug=debug,name=name`` 3998 ``spiceport`` is only available when spice support is built in. 3999 4000 ``debug`` debug level for spicevmc 4001 4002 ``name`` name of spice port to connect to 4003 4004 Connect to a spice port, allowing a Spice client to handle the 4005 traffic identified by a name (preferably a fqdn). 4006ERST 4007 4008DEFHEADING() 4009 4010#ifdef CONFIG_TPM 4011DEFHEADING(TPM device options:) 4012 4013DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 4014 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 4015 " use path to provide path to a character device; default is /dev/tpm0\n" 4016 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 4017 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 4018 "-tpmdev emulator,id=id,chardev=dev\n" 4019 " configure the TPM device using chardev backend\n", 4020 QEMU_ARCH_ALL) 4021SRST 4022The general form of a TPM device option is: 4023 4024``-tpmdev backend,id=id[,options]`` 4025 The specific backend type will determine the applicable options. The 4026 ``-tpmdev`` option creates the TPM backend and requires a 4027 ``-device`` option that specifies the TPM frontend interface model. 4028 4029 Use ``-tpmdev help`` to print all available TPM backend types. 4030 4031The available backends are: 4032 4033``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 4034 (Linux-host only) Enable access to the host's TPM using the 4035 passthrough driver. 4036 4037 ``path`` specifies the path to the host's TPM device, i.e., on a 4038 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 4039 default ``/dev/tpm0`` is used. 4040 4041 ``cancel-path`` specifies the path to the host TPM device's sysfs 4042 entry allowing for cancellation of an ongoing TPM command. 4043 ``cancel-path`` is optional and by default QEMU will search for the 4044 sysfs entry to use. 4045 4046 Some notes about using the host's TPM with the passthrough driver: 4047 4048 The TPM device accessed by the passthrough driver must not be used 4049 by any other application on the host. 4050 4051 Since the host's firmware (BIOS/UEFI) has already initialized the 4052 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 4053 the TPM again and may therefore not show a TPM-specific menu that 4054 would otherwise allow the user to configure the TPM, e.g., allow the 4055 user to enable/disable or activate/deactivate the TPM. Further, if 4056 TPM ownership is released from within a VM then the host's TPM will 4057 get disabled and deactivated. To enable and activate the TPM again 4058 afterwards, the host has to be rebooted and the user is required to 4059 enter the firmware's menu to enable and activate the TPM. If the TPM 4060 is left disabled and/or deactivated most TPM commands will fail. 4061 4062 To create a passthrough TPM use the following two options: 4063 4064 :: 4065 4066 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 4067 4068 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 4069 ``tpmdev=tpm0`` in the device option. 4070 4071``-tpmdev emulator,id=id,chardev=dev`` 4072 (Linux-host only) Enable access to a TPM emulator using Unix domain 4073 socket based chardev backend. 4074 4075 ``chardev`` specifies the unique ID of a character device backend 4076 that provides connection to the software TPM server. 4077 4078 To create a TPM emulator backend device with chardev socket backend: 4079 4080 :: 4081 4082 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 4083ERST 4084 4085DEFHEADING() 4086 4087#endif 4088 4089DEFHEADING(Boot Image or Kernel specific:) 4090SRST 4091There are broadly 4 ways you can boot a system with QEMU. 4092 4093 - specify a firmware and let it control finding a kernel 4094 - specify a firmware and pass a hint to the kernel to boot 4095 - direct kernel image boot 4096 - manually load files into the guest's address space 4097 4098The third method is useful for quickly testing kernels but as there is 4099no firmware to pass configuration information to the kernel the 4100hardware must either be probeable, the kernel built for the exact 4101configuration or passed some configuration data (e.g. a DTB blob) 4102which tells the kernel what drivers it needs. This exact details are 4103often hardware specific. 4104 4105The final method is the most generic way of loading images into the 4106guest address space and used mostly for ``bare metal`` type 4107development where the reset vectors of the processor are taken into 4108account. 4109 4110ERST 4111 4112SRST 4113 4114For x86 machines and some other architectures ``-bios`` will generally 4115do the right thing with whatever it is given. For other machines the 4116more strict ``-pflash`` option needs an image that is sized for the 4117flash device for the given machine type. 4118 4119Please see the :ref:`system-targets-ref` section of the manual for 4120more detailed documentation. 4121 4122ERST 4123 4124DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 4125 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4126SRST 4127``-bios file`` 4128 Set the filename for the BIOS. 4129ERST 4130 4131DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 4132 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 4133SRST 4134``-pflash file`` 4135 Use file as a parallel flash image. 4136ERST 4137 4138SRST 4139 4140The kernel options were designed to work with Linux kernels although 4141other things (like hypervisors) can be packaged up as a kernel 4142executable image. The exact format of a executable image is usually 4143architecture specific. 4144 4145The way in which the kernel is started (what address it is loaded at, 4146what if any information is passed to it via CPU registers, the state 4147of the hardware when it is started, and so on) is also architecture 4148specific. Typically it follows the specification laid down by the 4149Linux kernel for how kernels for that architecture must be started. 4150 4151ERST 4152 4153DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 4154 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 4155SRST 4156``-kernel bzImage`` 4157 Use bzImage as kernel image. The kernel can be either a Linux kernel 4158 or in multiboot format. 4159ERST 4160 4161DEF("shim", HAS_ARG, QEMU_OPTION_shim, \ 4162 "-shim shim.efi use 'shim.efi' to boot the kernel\n", QEMU_ARCH_ALL) 4163SRST 4164``-shim shim.efi`` 4165 Use 'shim.efi' to boot the kernel 4166ERST 4167 4168DEF("append", HAS_ARG, QEMU_OPTION_append, \ 4169 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 4170SRST 4171``-append cmdline`` 4172 Use cmdline as kernel command line 4173ERST 4174 4175DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4176 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4177SRST(initrd) 4178 4179``-initrd file`` 4180 Use file as initial ram disk. 4181 4182``-initrd "file1 arg=foo,file2"`` 4183 This syntax is only available with multiboot. 4184 4185 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4186 first module. Commas can be provided in module parameters by doubling 4187 them on the command line to escape them: 4188 4189``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4190 Multiboot only. Use bzImage as the first module with 4191 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4192 and initrd.img as the second module. 4193 4194ERST 4195 4196DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4197 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4198SRST 4199``-dtb file`` 4200 Use file as a device tree binary (dtb) image and pass it to the 4201 kernel on boot. 4202ERST 4203 4204SRST 4205 4206Finally you can also manually load images directly into the address 4207space of the guest. This is most useful for developers who already 4208know the layout of their guest and take care to ensure something sane 4209will happen when the reset vector executes. 4210 4211The generic loader can be invoked by using the loader device: 4212 4213``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4214 4215there is also the guest loader which operates in a similar way but 4216tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4217the guest image is: 4218 4219``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4220 4221ERST 4222 4223DEFHEADING() 4224 4225DEFHEADING(Debug/Expert options:) 4226 4227DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4228 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4229 " Policy for handling deprecated management interfaces\n" 4230 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4231 " Policy for handling unstable management interfaces\n", 4232 QEMU_ARCH_ALL) 4233SRST 4234``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4235 Set policy for handling deprecated management interfaces (experimental): 4236 4237 ``deprecated-input=accept`` (default) 4238 Accept deprecated commands and arguments 4239 ``deprecated-input=reject`` 4240 Reject deprecated commands and arguments 4241 ``deprecated-input=crash`` 4242 Crash on deprecated commands and arguments 4243 ``deprecated-output=accept`` (default) 4244 Emit deprecated command results and events 4245 ``deprecated-output=hide`` 4246 Suppress deprecated command results and events 4247 4248 Limitation: covers only syntactic aspects of QMP. 4249 4250``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4251 Set policy for handling unstable management interfaces (experimental): 4252 4253 ``unstable-input=accept`` (default) 4254 Accept unstable commands and arguments 4255 ``unstable-input=reject`` 4256 Reject unstable commands and arguments 4257 ``unstable-input=crash`` 4258 Crash on unstable commands and arguments 4259 ``unstable-output=accept`` (default) 4260 Emit unstable command results and events 4261 ``unstable-output=hide`` 4262 Suppress unstable command results and events 4263 4264 Limitation: covers only syntactic aspects of QMP. 4265ERST 4266 4267DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4268 "-fw_cfg [name=]<name>,file=<file>\n" 4269 " add named fw_cfg entry with contents from file\n" 4270 "-fw_cfg [name=]<name>,string=<str>\n" 4271 " add named fw_cfg entry with contents from string\n", 4272 QEMU_ARCH_ALL) 4273SRST 4274``-fw_cfg [name=]name,file=file`` 4275 Add named fw\_cfg entry with contents from file file. 4276 If the filename contains comma, you must double it (for instance, 4277 "file=my,,file" to use file "my,file"). 4278 4279``-fw_cfg [name=]name,string=str`` 4280 Add named fw\_cfg entry with contents from string str. 4281 If the string contains comma, you must double it (for instance, 4282 "string=my,,string" to use file "my,string"). 4283 4284 The terminating NUL character of the contents of str will not be 4285 included as part of the fw\_cfg item data. To insert contents with 4286 embedded NUL characters, you have to use the file parameter. 4287 4288 The fw\_cfg entries are passed by QEMU through to the guest. 4289 4290 Example: 4291 4292 :: 4293 4294 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4295 4296 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4297 from ./my\_blob.bin. 4298ERST 4299 4300DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4301 "-serial dev redirect the serial port to char device 'dev'\n", 4302 QEMU_ARCH_ALL) 4303SRST 4304``-serial dev`` 4305 Redirect the virtual serial port to host character device dev. The 4306 default device is ``vc`` in graphical mode and ``stdio`` in non 4307 graphical mode. 4308 4309 This option can be used several times to simulate multiple serial 4310 ports. 4311 4312 You can use ``-serial none`` to suppress the creation of default 4313 serial devices. 4314 4315 Available character devices are: 4316 4317 ``vc[:WxH]`` 4318 Virtual console. Optionally, a width and height can be given in 4319 pixel with 4320 4321 :: 4322 4323 vc:800x600 4324 4325 It is also possible to specify width or height in characters: 4326 4327 :: 4328 4329 vc:80Cx24C 4330 4331 ``pty[:path]`` 4332 [Linux only] Pseudo TTY (a new PTY is automatically allocated). 4333 4334 If ``path`` is specified, QEMU will create a symbolic link at 4335 that location which points to the new PTY device. 4336 4337 This avoids having to make QMP or HMP monitor queries to find 4338 out what the new PTY device path is. 4339 4340 Note that while QEMU will remove the symlink when it exits 4341 gracefully, it will not do so in case of crashes or on certain 4342 startup errors. It is recommended that the user checks and 4343 removes the symlink after QEMU terminates to account for this. 4344 4345 ``none`` 4346 No device is allocated. Note that for machine types which 4347 emulate systems where a serial device is always present in 4348 real hardware, this may be equivalent to the ``null`` option, 4349 in that the serial device is still present but all output 4350 is discarded. For boards where the number of serial ports is 4351 truly variable, this suppresses the creation of the device. 4352 4353 ``null`` 4354 A guest will see the UART or serial device as present in the 4355 machine, but all output is discarded, and there is no input. 4356 Conceptually equivalent to redirecting the output to ``/dev/null``. 4357 4358 ``chardev:id`` 4359 Use a named character device defined with the ``-chardev`` 4360 option. 4361 4362 ``/dev/XXX`` 4363 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4364 port parameters are set according to the emulated ones. 4365 4366 ``/dev/parportN`` 4367 [Linux only, parallel port only] Use host parallel port N. 4368 Currently SPP and EPP parallel port features can be used. 4369 4370 ``file:filename`` 4371 Write output to filename. No character can be read. 4372 4373 ``stdio`` 4374 [Unix only] standard input/output 4375 4376 ``pipe:filename`` 4377 name pipe filename 4378 4379 ``COMn`` 4380 [Windows only] Use host serial port n 4381 4382 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4383 This implements UDP Net Console. When remote\_host or src\_ip 4384 are not specified they default to ``0.0.0.0``. When not using a 4385 specified src\_port a random port is automatically chosen. 4386 4387 If you just want a simple readonly console you can use 4388 ``netcat`` or ``nc``, by starting QEMU with: 4389 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4390 QEMU writes something to that port it will appear in the 4391 netconsole session. 4392 4393 If you plan to send characters back via netconsole or you want 4394 to stop and start QEMU a lot of times, you should have QEMU use 4395 the same source port each time by using something like ``-serial 4396 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4397 version of netcat which can listen to a TCP port and send and 4398 receive characters via udp. If you have a patched version of 4399 netcat which activates telnet remote echo and single char 4400 transfer, then you can use the following options to set up a 4401 netcat redirector to allow telnet on port 5555 to access the 4402 QEMU port. 4403 4404 ``QEMU Options:`` 4405 -serial udp::4555@:4556 4406 4407 ``netcat options:`` 4408 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4409 4410 ``telnet options:`` 4411 localhost 5555 4412 4413 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect-ms=milliseconds]`` 4414 The TCP Net Console has two modes of operation. It can send the 4415 serial I/O to a location or wait for a connection from a 4416 location. By default the TCP Net Console is sent to host at the 4417 port. If you use the ``server=on`` option QEMU will wait for a client 4418 socket application to connect to the port before continuing, 4419 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4420 option disables the Nagle buffering algorithm. The ``reconnect-ms`` 4421 option only applies if ``server=no`` is set, if the connection goes 4422 down it will attempt to reconnect at the given interval. If host 4423 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4424 time is accepted. You can use ``telnet=on`` to connect to the 4425 corresponding character device. 4426 4427 ``Example to send tcp console to 192.168.0.2 port 4444`` 4428 -serial tcp:192.168.0.2:4444 4429 4430 ``Example to listen and wait on port 4444 for connection`` 4431 -serial tcp::4444,server=on 4432 4433 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4434 -serial tcp:192.168.0.100:4444,server=on,wait=off 4435 4436 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4437 The telnet protocol is used instead of raw tcp sockets. The 4438 options work the same as if you had specified ``-serial tcp``. 4439 The difference is that the port acts like a telnet server or 4440 client using telnet option negotiation. This will also allow you 4441 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4442 supports sending the break sequence. Typically in unix telnet 4443 you do it with Control-] and then type "send break" followed by 4444 pressing the enter key. 4445 4446 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4447 The WebSocket protocol is used instead of raw tcp socket. The 4448 port acts as a WebSocket server. Client mode is not supported. 4449 4450 ``unix:path[,server=on|off][,wait=on|off][,reconnect-ms=milliseconds]`` 4451 A unix domain socket is used instead of a tcp socket. The option 4452 works the same as if you had specified ``-serial tcp`` except 4453 the unix domain socket path is used for connections. 4454 4455 ``mon:dev_string`` 4456 This is a special option to allow the monitor to be multiplexed 4457 onto another serial port. The monitor is accessed with key 4458 sequence of Control-a and then pressing c. dev\_string should be 4459 any one of the serial devices specified above. An example to 4460 multiplex the monitor onto a telnet server listening on port 4461 4444 would be: 4462 4463 ``-serial mon:telnet::4444,server=on,wait=off`` 4464 4465 When the monitor is multiplexed to stdio in this way, Ctrl+C 4466 will not terminate QEMU any more but will be passed to the guest 4467 instead. 4468 4469 ``braille`` 4470 Braille device. This will use BrlAPI to display the braille 4471 output on a real or fake device. 4472 4473 ``msmouse`` 4474 Three button serial mouse. Configure the guest to use Microsoft 4475 protocol. 4476ERST 4477 4478DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4479 "-parallel dev redirect the parallel port to char device 'dev'\n", 4480 QEMU_ARCH_ALL) 4481SRST 4482``-parallel dev`` 4483 Redirect the virtual parallel port to host device dev (same devices 4484 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4485 to use hardware devices connected on the corresponding host parallel 4486 port. 4487 4488 This option can be used several times to simulate up to 3 parallel 4489 ports. 4490 4491 Use ``-parallel none`` to disable all parallel ports. 4492ERST 4493 4494DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4495 "-monitor dev redirect the monitor to char device 'dev'\n", 4496 QEMU_ARCH_ALL) 4497SRST 4498``-monitor dev`` 4499 Redirect the monitor to host device dev (same devices as the serial 4500 port). The default device is ``vc`` in graphical mode and ``stdio`` 4501 in non graphical mode. Use ``-monitor none`` to disable the default 4502 monitor. 4503ERST 4504DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4505 "-qmp dev like -monitor but opens in 'control' mode\n", 4506 QEMU_ARCH_ALL) 4507SRST 4508``-qmp dev`` 4509 Like ``-monitor`` but opens in 'control' mode. For example, to make 4510 QMP available on localhost port 4444:: 4511 4512 -qmp tcp:localhost:4444,server=on,wait=off 4513 4514 Not all options are configurable via this syntax; for maximum 4515 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4516 4517ERST 4518DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4519 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4520 QEMU_ARCH_ALL) 4521SRST 4522``-qmp-pretty dev`` 4523 Like ``-qmp`` but uses pretty JSON formatting. 4524ERST 4525 4526DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4527 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4528SRST 4529``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4530 Set up a monitor connected to the chardev ``name``. 4531 QEMU supports two monitors: the Human Monitor Protocol 4532 (HMP; for human interaction), and the QEMU Monitor Protocol 4533 (QMP; a JSON RPC-style protocol). 4534 The default is HMP; ``mode=control`` selects QMP instead. 4535 ``pretty`` is only valid when ``mode=control``, 4536 turning on JSON pretty printing to ease 4537 human reading and debugging. 4538 4539 For example:: 4540 4541 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4542 -mon chardev=mon1,mode=control,pretty=on 4543 4544 enables the QMP monitor on localhost port 4444 with pretty-printing. 4545ERST 4546 4547DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4548 "-debugcon dev redirect the debug console to char device 'dev'\n", 4549 QEMU_ARCH_ALL) 4550SRST 4551``-debugcon dev`` 4552 Redirect the debug console to host device dev (same devices as the 4553 serial port). The debug console is an I/O port which is typically 4554 port 0xe9; writing to that I/O port sends output to this device. The 4555 default device is ``vc`` in graphical mode and ``stdio`` in non 4556 graphical mode. 4557ERST 4558 4559DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4560 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4561SRST 4562``-pidfile file`` 4563 Store the QEMU process PID in file. It is useful if you launch QEMU 4564 from a script. 4565ERST 4566 4567DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4568 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4569 QEMU_ARCH_ALL) 4570SRST 4571``--preconfig`` 4572 Pause QEMU for interactive configuration before the machine is 4573 created, which allows querying and configuring properties that will 4574 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4575 exit the preconfig state and move to the next state (i.e. run guest 4576 if -S isn't used or pause the second time if -S is used). This 4577 option is experimental. 4578ERST 4579 4580DEF("S", 0, QEMU_OPTION_S, \ 4581 "-S freeze CPU at startup (use 'c' to start execution)\n", 4582 QEMU_ARCH_ALL) 4583SRST 4584``-S`` 4585 Do not start CPU at startup (you must type 'c' in the monitor). 4586ERST 4587 4588DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4589 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4590 " run qemu with overcommit hints\n" 4591 " mem-lock=on|off controls memory lock support (default: off)\n" 4592 " cpu-pm=on|off controls cpu power management (default: off)\n", 4593 QEMU_ARCH_ALL) 4594SRST 4595``-overcommit mem-lock=on|off`` 4596 \ 4597``-overcommit cpu-pm=on|off`` 4598 Run qemu with hints about host resource overcommit. The default is 4599 to assume that host overcommits all resources. 4600 4601 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4602 (disabled by default). This works when host memory is not 4603 overcommitted and reduces the worst-case latency for guest. 4604 4605 Guest ability to manage power state of host cpus (increasing latency 4606 for other processes on the same host cpu, but decreasing latency for 4607 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4608 works best when host CPU is not overcommitted. When used, host 4609 estimates of CPU cycle and power utilization will be incorrect, not 4610 taking into account guest idle time. 4611ERST 4612 4613DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4614 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4615 " the guest without waiting for gdb to connect; use -S too\n" 4616 " if you want it to not start execution.)\n", 4617 QEMU_ARCH_ALL) 4618SRST 4619``-gdb dev`` 4620 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4621 in the System Emulation Users Guide). Note that this option does not pause QEMU 4622 execution -- if you want QEMU to not start the guest until you 4623 connect with gdb and issue a ``continue`` command, you will need to 4624 also pass the ``-S`` option to QEMU. 4625 4626 The most usual configuration is to listen on a local TCP socket:: 4627 4628 -gdb tcp::3117 4629 4630 but you can specify other backends; UDP, pseudo TTY, or even stdio 4631 are all reasonable use cases. For example, a stdio connection 4632 allows you to start QEMU from within gdb and establish the 4633 connection via a pipe: 4634 4635 .. parsed-literal:: 4636 4637 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4638ERST 4639 4640DEF("s", 0, QEMU_OPTION_s, \ 4641 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4642 QEMU_ARCH_ALL) 4643SRST 4644``-s`` 4645 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4646 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4647ERST 4648 4649DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4650 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4651 QEMU_ARCH_ALL) 4652SRST 4653``-d item1[,...]`` 4654 Enable logging of specified items. Use '-d help' for a list of log 4655 items. 4656ERST 4657 4658DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4659 "-D logfile output log to logfile (default stderr)\n", 4660 QEMU_ARCH_ALL) 4661SRST 4662``-D logfile`` 4663 Output log in logfile instead of to stderr 4664ERST 4665 4666DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4667 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4668 QEMU_ARCH_ALL) 4669SRST 4670``-dfilter range1[,...]`` 4671 Filter debug output to that relevant to a range of target addresses. 4672 The filter spec can be either start+size, start-size or start..end 4673 where start end and size are the addresses and sizes required. For 4674 example: 4675 4676 :: 4677 4678 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4679 4680 Will dump output for any code in the 0x1000 sized block starting at 4681 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4682 another 0x1000 sized block starting at 0xffffffc00005f000. 4683ERST 4684 4685DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4686 "-seed number seed the pseudo-random number generator\n", 4687 QEMU_ARCH_ALL) 4688SRST 4689``-seed number`` 4690 Force the guest to use a deterministic pseudo-random number 4691 generator, seeded with number. This does not affect crypto routines 4692 within the host. 4693ERST 4694 4695DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4696 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4697 QEMU_ARCH_ALL) 4698SRST 4699``-L path`` 4700 Set the directory for the BIOS, VGA BIOS and keymaps. 4701 4702 To list all the data directories, use ``-L help``. 4703ERST 4704 4705DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4706 "-enable-kvm enable KVM full virtualization support\n", 4707 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4708 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4709SRST 4710``-enable-kvm`` 4711 Enable KVM full virtualization support. This option is only 4712 available if KVM support is enabled when compiling. 4713ERST 4714 4715DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4716 "-xen-domid id specify xen guest domain id\n", 4717 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4718DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4719 "-xen-attach attach to existing xen domain\n" 4720 " libxl will use this when starting QEMU\n", 4721 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4722DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4723 "-xen-domid-restrict restrict set of available xen operations\n" 4724 " to specified domain id. (Does not affect\n" 4725 " xenpv machine type).\n", 4726 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4727SRST 4728``-xen-domid id`` 4729 Specify xen guest domain id (XEN only). 4730 4731``-xen-attach`` 4732 Attach to existing xen domain. libxl will use this when starting 4733 QEMU (XEN only). Restrict set of available xen operations to 4734 specified domain id (XEN only). 4735ERST 4736 4737DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4738 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4739SRST 4740``-no-reboot`` 4741 Exit instead of rebooting. 4742ERST 4743 4744DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4745 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4746SRST 4747``-no-shutdown`` 4748 Don't exit QEMU on guest shutdown, but instead only stop the 4749 emulation. This allows for instance switching to monitor to commit 4750 changes to the disk image. 4751ERST 4752 4753DEF("action", HAS_ARG, QEMU_OPTION_action, 4754 "-action reboot=reset|shutdown\n" 4755 " action when guest reboots [default=reset]\n" 4756 "-action shutdown=poweroff|pause\n" 4757 " action when guest shuts down [default=poweroff]\n" 4758 "-action panic=pause|shutdown|exit-failure|none\n" 4759 " action when guest panics [default=shutdown]\n" 4760 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4761 " action when watchdog fires [default=reset]\n", 4762 QEMU_ARCH_ALL) 4763SRST 4764``-action event=action`` 4765 The action parameter serves to modify QEMU's default behavior when 4766 certain guest events occur. It provides a generic method for specifying the 4767 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4768 parameters. 4769 4770 Examples: 4771 4772 ``-action panic=none`` 4773 ``-action reboot=shutdown,shutdown=pause`` 4774 ``-device i6300esb -action watchdog=pause`` 4775 4776ERST 4777 4778DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4779 "-loadvm [tag|id]\n" \ 4780 " start right away with a saved state (loadvm in monitor)\n", 4781 QEMU_ARCH_ALL) 4782SRST 4783``-loadvm file`` 4784 Start right away with a saved state (``loadvm`` in monitor) 4785ERST 4786 4787#ifndef _WIN32 4788DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4789 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4790#endif 4791SRST 4792``-daemonize`` 4793 Daemonize the QEMU process after initialization. QEMU will not 4794 detach from standard IO until it is ready to receive connections on 4795 any of its devices. This option is a useful way for external 4796 programs to launch QEMU without having to cope with initialization 4797 race conditions. 4798ERST 4799 4800DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4801 "-option-rom rom load a file, rom, into the option ROM space\n", 4802 QEMU_ARCH_ALL) 4803SRST 4804``-option-rom file`` 4805 Load the contents of file as an option ROM. This option is useful to 4806 load things like EtherBoot. 4807ERST 4808 4809DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4810 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4811 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4812 QEMU_ARCH_ALL) 4813 4814SRST 4815``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4816 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4817 the current UTC or local time, respectively. ``localtime`` is 4818 required for correct date in MS-DOS or Windows. To start at a 4819 specific point in time, provide datetime in the format 4820 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4821 4822 By default the RTC is driven by the host system time. This allows 4823 using of the RTC as accurate reference clock inside the guest, 4824 specifically if the host time is smoothly following an accurate 4825 external reference clock, e.g. via NTP. If you want to isolate the 4826 guest time from the host, you can set ``clock`` to ``rt`` instead, 4827 which provides a host monotonic clock if host support it. To even 4828 prevent the RTC from progressing during suspension, you can set 4829 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4830 recommended especially in icount mode in order to preserve 4831 determinism; however, note that in icount mode the speed of the 4832 virtual clock is variable and can in general differ from the host 4833 clock. 4834 4835 Enable ``driftfix`` (i386 targets only) if you experience time drift 4836 problems, specifically with Windows' ACPI HAL. This option will try 4837 to figure out how many timer interrupts were not processed by the 4838 Windows guest and will re-inject them. 4839ERST 4840 4841DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4842 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4843 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4844 " instruction, enable aligning the host and virtual clocks\n" \ 4845 " or disable real time cpu sleeping, and optionally enable\n" \ 4846 " record-and-replay mode\n", QEMU_ARCH_ALL) 4847SRST 4848``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4849 Enable virtual instruction counter. The virtual cpu will execute one 4850 instruction every 2^N ns of virtual time. If ``auto`` is specified 4851 then the virtual cpu speed will be automatically adjusted to keep 4852 virtual time within a few seconds of real time. 4853 4854 Note that while this option can give deterministic behavior, it does 4855 not provide cycle accurate emulation. Modern CPUs contain 4856 superscalar out of order cores with complex cache hierarchies. The 4857 number of instructions executed often has little or no correlation 4858 with actual performance. 4859 4860 When the virtual cpu is sleeping, the virtual time will advance at 4861 default speed unless ``sleep=on`` is specified. With 4862 ``sleep=on``, the virtual time will jump to the next timer 4863 deadline instantly whenever the virtual cpu goes to sleep mode and 4864 will not advance if no timer is enabled. This behavior gives 4865 deterministic execution times from the guest point of view. 4866 The default if icount is enabled is ``sleep=off``. 4867 ``sleep=on`` cannot be used together with either ``shift=auto`` 4868 or ``align=on``. 4869 4870 ``align=on`` will activate the delay algorithm which will try to 4871 synchronise the host clock and the virtual clock. The goal is to 4872 have a guest running at the real frequency imposed by the shift 4873 option. Whenever the guest clock is behind the host clock and if 4874 ``align=on`` is specified then we print a message to the user to 4875 inform about the delay. Currently this option does not work when 4876 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4877 shift values for which the guest clock runs ahead of the host clock. 4878 Typically this happens when the shift value is high (how high 4879 depends on the host machine). The default if icount is enabled 4880 is ``align=off``. 4881 4882 When the ``rr`` option is specified deterministic record/replay is 4883 enabled. The ``rrfile=`` option must also be provided to 4884 specify the path to the replay log. In record mode data is written 4885 to this file, and in replay mode it is read back. 4886 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4887 name. In record mode, a new VM snapshot with the given name is created 4888 at the start of execution recording. In replay mode this option 4889 specifies the snapshot name used to load the initial VM state. 4890ERST 4891 4892DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4893 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4894 " action when watchdog fires [default=reset]\n", 4895 QEMU_ARCH_ALL) 4896SRST 4897``-watchdog-action action`` 4898 The action controls what QEMU will do when the watchdog timer 4899 expires. The default is ``reset`` (forcefully reset the guest). 4900 Other possible actions are: ``shutdown`` (attempt to gracefully 4901 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4902 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4903 guest), ``debug`` (print a debug message and continue), or ``none`` 4904 (do nothing). 4905 4906 Note that the ``shutdown`` action requires that the guest responds 4907 to ACPI signals, which it may not be able to do in the sort of 4908 situations where the watchdog would have expired, and thus 4909 ``-watchdog-action shutdown`` is not recommended for production use. 4910 4911 Examples: 4912 4913 ``-device i6300esb -watchdog-action pause`` 4914 4915ERST 4916 4917DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4918 "-echr chr set terminal escape character instead of ctrl-a\n", 4919 QEMU_ARCH_ALL) 4920SRST 4921``-echr numeric_ascii_value`` 4922 Change the escape character used for switching to the monitor when 4923 using monitor and serial sharing. The default is ``0x01`` when using 4924 the ``-nographic`` option. ``0x01`` is equal to pressing 4925 ``Control-a``. You can select a different character from the ascii 4926 control keys where 1 through 26 map to Control-a through Control-z. 4927 For instance you could use the either of the following to change the 4928 escape character to Control-t. 4929 4930 ``-echr 0x14``; \ ``-echr 20`` 4931 4932ERST 4933 4934DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4935 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4936 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4937 "-incoming unix:socketpath\n" \ 4938 " prepare for incoming migration, listen on\n" \ 4939 " specified protocol and socket address\n" \ 4940 "-incoming fd:fd\n" \ 4941 "-incoming file:filename[,offset=offset]\n" \ 4942 "-incoming exec:cmdline\n" \ 4943 " accept incoming migration on given file descriptor\n" \ 4944 " or from given external command\n" \ 4945 "-incoming <channel>\n" \ 4946 " accept incoming migration on the migration channel\n" \ 4947 "-incoming defer\n" \ 4948 " wait for the URI to be specified via migrate_incoming\n", 4949 QEMU_ARCH_ALL) 4950SRST 4951The -incoming option specifies the migration channel for an incoming 4952migration. It may be used multiple times to specify multiple 4953migration channel types. The channel type is specified in <channel>, 4954or is 'main' for all other forms of -incoming. If multiple -incoming 4955options are specified for a channel type, the last one takes precedence. 4956 4957``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4958 \ 4959``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4960 Prepare for incoming migration, listen on a given tcp port. 4961 4962``-incoming unix:socketpath`` 4963 Prepare for incoming migration, listen on a given unix socket. 4964 4965``-incoming fd:fd`` 4966 Accept incoming migration from a given file descriptor. 4967 4968``-incoming file:filename[,offset=offset]`` 4969 Accept incoming migration from a given file starting at offset. 4970 offset allows the common size suffixes, or a 0x prefix, but not both. 4971 4972``-incoming exec:cmdline`` 4973 Accept incoming migration as an output from specified external 4974 command. 4975 4976``-incoming <channel>`` 4977 Accept incoming migration on the migration channel. For the syntax 4978 of <channel>, see the QAPI documentation of ``MigrationChannel``. 4979 Examples: 4980 :: 4981 4982 -incoming '{"channel-type": "main", 4983 "addr": { "transport": "socket", 4984 "type": "unix", 4985 "path": "my.sock" }}' 4986 4987 -incoming main,addr.transport=socket,addr.type=unix,addr.path=my.sock 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 5013DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 5014 "-prom-env variable=value\n" 5015 " set OpenBIOS nvram variables\n", 5016 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 5017SRST 5018``-prom-env variable=value`` 5019 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 5020 5021 :: 5022 5023 qemu-system-sparc -prom-env 'auto-boot?=false' \ 5024 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 5025 5026 :: 5027 5028 qemu-system-ppc -prom-env 'auto-boot?=false' \ 5029 -prom-env 'boot-device=hd:2,\yaboot' \ 5030 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 5031ERST 5032DEF("semihosting", 0, QEMU_OPTION_semihosting, 5033 "-semihosting semihosting mode\n", 5034 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 5035 QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 5036SRST 5037``-semihosting`` 5038 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, RISC-V only). 5039 5040 .. warning:: 5041 Note that this allows guest direct access to the host filesystem, so 5042 should only be used with a trusted guest OS. 5043 5044 See the -semihosting-config option documentation for further 5045 information about the facilities this enables. 5046ERST 5047DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 5048 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 5049 " semihosting configuration\n", 5050QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 5051QEMU_ARCH_MIPS | QEMU_ARCH_RISCV) 5052SRST 5053``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 5054 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, RISC-V 5055 only). 5056 5057 .. warning:: 5058 Note that this allows guest direct access to the host filesystem, so 5059 should only be used with a trusted guest OS. 5060 5061 ``target=native|gdb|auto`` 5062 Defines where the semihosting calls will be addressed, to QEMU 5063 (``native``) or to GDB (``gdb``). The default is ``auto``, which 5064 means ``gdb`` during debug sessions and ``native`` otherwise. 5065 5066 ``chardev=str1`` 5067 Send the output to a chardev backend output for native or auto 5068 output when not in gdb 5069 5070 ``userspace=on|off`` 5071 Allows code running in guest userspace to access the semihosting 5072 interface. The default is that only privileged guest code can 5073 make semihosting calls. Note that setting ``userspace=on`` should 5074 only be used if all guest code is trusted (for example, in 5075 bare-metal test case code). 5076 5077 ``arg=str1,arg=str2,...`` 5078 Allows the user to pass input arguments, and can be used 5079 multiple times to build up a list. The old-style 5080 ``-kernel``/``-append`` method of passing a command line is 5081 still supported for backward compatibility. If both the 5082 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 5083 specified, the former is passed to semihosting as it always 5084 takes precedence. 5085ERST 5086DEF("old-param", 0, QEMU_OPTION_old_param, 5087 "-old-param old param mode\n", QEMU_ARCH_ARM) 5088SRST 5089``-old-param`` 5090 Old param mode (ARM only). 5091ERST 5092 5093DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 5094 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 5095 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 5096 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 5097 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 5098 " by the kernel, but typically no longer used by modern\n" \ 5099 " C library implementations.\n" \ 5100 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 5101 " to elevate privileges using set*uid|gid system calls.\n" \ 5102 " The value 'children' will deny set*uid|gid system calls for\n" \ 5103 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 5104 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 5105 " blocking *fork and execve\n" \ 5106 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 5107 QEMU_ARCH_ALL) 5108SRST 5109``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 5110 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 5111 filtering and 'off' will disable it. The default is 'off'. 5112 5113 ``obsolete=string`` 5114 Enable Obsolete system calls 5115 5116 ``elevateprivileges=string`` 5117 Disable set\*uid\|gid system calls 5118 5119 ``spawn=string`` 5120 Disable \*fork and execve 5121 5122 ``resourcecontrol=string`` 5123 Disable process affinity and schedular priority 5124ERST 5125 5126DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 5127 "-readconfig <file>\n" 5128 " read config file\n", QEMU_ARCH_ALL) 5129SRST 5130``-readconfig file`` 5131 Read device configuration from file. This approach is useful when 5132 you want to spawn QEMU process with many command line options but 5133 you don't want to exceed the command line character limit. 5134ERST 5135 5136DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 5137 "-no-user-config\n" 5138 " do not load default user-provided config files at startup\n", 5139 QEMU_ARCH_ALL) 5140SRST 5141``-no-user-config`` 5142 The ``-no-user-config`` option makes QEMU not load any of the 5143 user-provided config files on sysconfdir. 5144ERST 5145 5146DEF("trace", HAS_ARG, QEMU_OPTION_trace, 5147 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 5148 " specify tracing options\n", 5149 QEMU_ARCH_ALL) 5150SRST 5151``-trace [[enable=]pattern][,events=file][,file=file]`` 5152 .. include:: ../qemu-option-trace.rst.inc 5153 5154ERST 5155DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 5156 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 5157 " load a plugin\n", 5158 QEMU_ARCH_ALL) 5159SRST 5160``-plugin file=file[,argname=argvalue]`` 5161 Load a plugin. 5162 5163 ``file=file`` 5164 Load the given plugin from a shared library file. 5165 5166 ``argname=argvalue`` 5167 Argument passed to the plugin. (Can be given multiple times.) 5168ERST 5169 5170HXCOMM Internal use 5171DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 5172DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 5173 5174#ifdef CONFIG_POSIX 5175DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 5176 "-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]\n" 5177 " Set miscellaneous QEMU process lifecycle options:\n" 5178 " async-teardown=on enables asynchronous teardown (Linux only)\n" 5179 " chroot=dir chroot to dir just before starting the VM\n" 5180 " user=username switch to the specified user before starting the VM\n" 5181 " user=uid:gid ditto, but use specified user-ID and group-ID instead\n", 5182 QEMU_ARCH_ALL) 5183SRST 5184``-run-with [async-teardown=on|off][,chroot=dir][user=username|uid:gid]`` 5185 Set QEMU process lifecycle options. 5186 5187 ``async-teardown=on`` enables asynchronous teardown. A new process called 5188 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5189 space with the main QEMU process, using clone. It will wait for the 5190 main QEMU process to terminate completely, and then exit. This allows 5191 QEMU to terminate very quickly even if the guest was huge, leaving the 5192 teardown of the address space to the cleanup process. Since the cleanup 5193 process shares the same cgroups as the main QEMU process, accounting is 5194 performed correctly. This only works if the cleanup process is not 5195 forcefully killed with SIGKILL before the main QEMU process has 5196 terminated completely. 5197 5198 ``chroot=dir`` can be used for doing a chroot to the specified directory 5199 immediately before starting the guest execution. This is especially useful 5200 in combination with ``user=...``. 5201 5202 ``user=username`` or ``user=uid:gid`` can be used to drop root privileges 5203 before starting guest execution. QEMU will use the ``setuid`` and ``setgid`` 5204 system calls to switch to the specified identity. Note that the 5205 ``user=username`` syntax will also apply the full set of supplementary 5206 groups for the user, whereas the ``user=uid:gid`` will use only the 5207 ``gid`` group. 5208ERST 5209#endif 5210 5211DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5212 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5213 " control error message format\n" 5214 " timestamp=on enables timestamps (default: off)\n" 5215 " guest-name=on enables guest name prefix but only if\n" 5216 " -name guest option is set (default: off)\n", 5217 QEMU_ARCH_ALL) 5218SRST 5219``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5220 Control error message format. 5221 5222 ``timestamp=on|off`` 5223 Prefix messages with a timestamp. Default is off. 5224 5225 ``guest-name=on|off`` 5226 Prefix messages with guest name but only if -name guest option is set 5227 otherwise the option is ignored. Default is off. 5228ERST 5229 5230DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5231 "-dump-vmstate <file>\n" 5232 " Output vmstate information in JSON format to file.\n" 5233 " Use the scripts/vmstate-static-checker.py file to\n" 5234 " check for possible regressions in migration code\n" 5235 " by comparing two such vmstate dumps.\n", 5236 QEMU_ARCH_ALL) 5237SRST 5238``-dump-vmstate file`` 5239 Dump json-encoded vmstate information for current machine type to 5240 file in file 5241ERST 5242 5243DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5244 "-enable-sync-profile\n" 5245 " enable synchronization profiling\n", 5246 QEMU_ARCH_ALL) 5247SRST 5248``-enable-sync-profile`` 5249 Enable synchronization profiling. 5250ERST 5251 5252#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5253DEF("perfmap", 0, QEMU_OPTION_perfmap, 5254 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5255 QEMU_ARCH_ALL) 5256SRST 5257``-perfmap`` 5258 Generate a map file for Linux perf tools that will allow basic profiling 5259 information to be broken down into basic blocks. 5260ERST 5261 5262DEF("jitdump", 0, QEMU_OPTION_jitdump, 5263 "-jitdump generate a jit-${pid}.dump file for perf\n", 5264 QEMU_ARCH_ALL) 5265SRST 5266``-jitdump`` 5267 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5268 names, line numbers and JITted code. 5269ERST 5270#endif 5271 5272DEFHEADING() 5273 5274DEFHEADING(Generic object creation:) 5275 5276DEF("object", HAS_ARG, QEMU_OPTION_object, 5277 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5278 " create a new object of type TYPENAME setting properties\n" 5279 " in the order they are specified. Note that the 'id'\n" 5280 " property must be set. These objects are placed in the\n" 5281 " '/objects' path.\n", 5282 QEMU_ARCH_ALL) 5283SRST 5284``-object typename[,prop1=value1,...]`` 5285 Create a new object of type typename setting properties in the order 5286 they are specified. Note that the 'id' property must be set. These 5287 objects are placed in the '/objects' path. 5288 5289 ``-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`` 5290 Creates a memory file backend object, which can be used to back 5291 the guest RAM with huge pages. 5292 5293 The ``id`` parameter is a unique ID that will be used to 5294 reference this memory region in other parameters, e.g. ``-numa``, 5295 ``-device nvdimm``, etc. 5296 5297 The ``size`` option provides the size of the memory region, and 5298 accepts common suffixes, e.g. ``500M``. 5299 5300 The ``mem-path`` provides the path to either a shared memory or 5301 huge page filesystem mount. 5302 5303 The ``share`` boolean option determines whether the memory 5304 region is marked as private to QEMU, or shared. The latter 5305 allows a co-operating external process to access the QEMU memory 5306 region. 5307 5308 Setting share=on might affect the ability to configure NUMA 5309 bindings for the memory backend under some circumstances, see 5310 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5311 source tree for additional details. 5312 5313 Setting the ``discard-data`` boolean option to on indicates that 5314 file contents can be destroyed when QEMU exits, to avoid 5315 unnecessarily flushing data to the backing file. Note that 5316 ``discard-data`` is only an optimization, and QEMU might not 5317 discard file contents if it aborts unexpectedly or is terminated 5318 using SIGKILL. 5319 5320 The ``merge`` boolean option enables memory merge, also known as 5321 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5322 the pages for memory deduplication. 5323 5324 Setting the ``dump`` boolean option to off excludes the memory 5325 from core dumps. This feature is also known as MADV\_DONTDUMP. 5326 5327 The ``prealloc`` boolean option enables memory preallocation. 5328 5329 The ``host-nodes`` option binds the memory range to a list of 5330 NUMA host nodes. 5331 5332 The ``policy`` option sets the NUMA policy to one of the 5333 following values: 5334 5335 ``default`` 5336 default host policy 5337 5338 ``preferred`` 5339 prefer the given host node list for allocation 5340 5341 ``bind`` 5342 restrict memory allocation to the given host node list 5343 5344 ``interleave`` 5345 interleave memory allocations across the given host node 5346 list 5347 5348 The ``align`` option specifies the base address alignment when 5349 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5350 ``2M``. Some backend store specified by ``mem-path`` requires an 5351 alignment different than the default one used by QEMU, eg the 5352 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5353 such cases, users can specify the required alignment via this 5354 option. 5355 5356 The ``offset`` option specifies the offset into the target file 5357 that the region starts at. You can use this parameter to back 5358 multiple regions with a single file. 5359 5360 The ``pmem`` option specifies whether the backing file specified 5361 by ``mem-path`` is in host persistent memory that can be 5362 accessed using the SNIA NVM programming model (e.g. Intel 5363 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5364 operations to guarantee the persistence of its own writes to 5365 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5366 migration). Also, we will map the backend-file with MAP\_SYNC 5367 flag, which ensures the file metadata is in sync for 5368 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5369 requires support from both the host kernel (since Linux kernel 5370 4.15) and the filesystem of ``mem-path`` mounted with DAX 5371 option. 5372 5373 The ``readonly`` option specifies whether the backing file is opened 5374 read-only or read-write (default). 5375 5376 The ``rom`` option specifies whether to create Read Only Memory 5377 (ROM) that cannot be modified by the VM. Any write attempts to such 5378 ROM will be denied. Most use cases want proper RAM instead of ROM. 5379 However, selected use cases, like R/O NVDIMMs, can benefit from 5380 ROM. If set to ``on``, create ROM; if set to ``off``, create 5381 writable RAM; if set to ``auto`` (default), the value of the 5382 ``readonly`` option is used. This option is primarily helpful when 5383 we want to have writable RAM in configurations that would 5384 traditionally create ROM before the ``rom`` option was introduced: 5385 VM templating, where we want to open a file readonly 5386 (``readonly=on``) and mark the memory to be private for QEMU 5387 (``share=off``). For this use case, we need writable RAM instead 5388 of ROM, and want to also set ``rom=off``. 5389 5390 ``-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`` 5391 Creates a memory backend object, which can be used to back the 5392 guest RAM. Memory backend objects offer more control than the 5393 ``-m`` option that is traditionally used to define guest RAM. 5394 Please refer to ``memory-backend-file`` for a description of the 5395 options. 5396 5397 ``-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`` 5398 Creates an anonymous memory file backend object, which allows 5399 QEMU to share the memory with an external process (e.g. when 5400 using vhost-user). The memory is allocated with memfd and 5401 optional sealing. (Linux only) 5402 5403 The ``seal`` option creates a sealed-file, that will block 5404 further resizing the memory ('on' by default). 5405 5406 The ``hugetlb`` option specify the file to be created resides in 5407 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5408 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5409 the hugetlb page size on systems that support multiple hugetlb 5410 page sizes (it must be a power of 2 value supported by the 5411 system). 5412 5413 In some versions of Linux, the ``hugetlb`` option is 5414 incompatible with the ``seal`` option (requires at least Linux 5415 4.16). 5416 5417 Please refer to ``memory-backend-file`` for a description of the 5418 other options. 5419 5420 The ``share`` boolean option is on by default with memfd. 5421 5422 ``-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`` 5423 Creates a POSIX shared memory backend object, which allows 5424 QEMU to share the memory with an external process (e.g. when 5425 using vhost-user). 5426 5427 ``memory-backend-shm`` is a more portable and less featureful version 5428 of ``memory-backend-memfd``. It can then be used in any POSIX system, 5429 especially when memfd is not supported. 5430 5431 Please refer to ``memory-backend-file`` for a description of the 5432 options. 5433 5434 The ``share`` boolean option is on by default with shm. Setting it to 5435 off will cause a failure during allocation because it is not supported 5436 by this backend. 5437 5438 ``-object iommufd,id=id[,fd=fd]`` 5439 Creates an iommufd backend which allows control of DMA mapping 5440 through the ``/dev/iommu`` device. 5441 5442 The ``id`` parameter is a unique ID which frontends (such as 5443 vfio-pci of vdpa) will use to connect with the iommufd backend. 5444 5445 The ``fd`` parameter is an optional pre-opened file descriptor 5446 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5447 across all subsystems, bringing the benefit of centralized 5448 reference counting. 5449 5450 ``-object rng-builtin,id=id`` 5451 Creates a random number generator backend which obtains entropy 5452 from QEMU builtin functions. The ``id`` parameter is a unique ID 5453 that will be used to reference this entropy backend from the 5454 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5455 uses this RNG backend. 5456 5457 ``-object rng-random,id=id,filename=/dev/random`` 5458 Creates a random number generator backend which obtains entropy 5459 from a device on the host. The ``id`` parameter is a unique ID 5460 that will be used to reference this entropy backend from the 5461 ``virtio-rng`` device. The ``filename`` parameter specifies 5462 which file to obtain entropy from and if omitted defaults to 5463 ``/dev/urandom``. 5464 5465 ``-object rng-egd,id=id,chardev=chardevid`` 5466 Creates a random number generator backend which obtains entropy 5467 from an external daemon running on the host. The ``id`` 5468 parameter is a unique ID that will be used to reference this 5469 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5470 parameter is the unique ID of a character device backend that 5471 provides the connection to the RNG daemon. 5472 5473 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5474 Creates a TLS anonymous credentials object, which can be used to 5475 provide TLS support on network backends. The ``id`` parameter is 5476 a unique ID which network backends will use to access the 5477 credentials. The ``endpoint`` is either ``server`` or ``client`` 5478 depending on whether the QEMU network backend that uses the 5479 credentials will be acting as a client or as a server. If 5480 ``verify-peer`` is enabled (the default) then once the handshake 5481 is completed, the peer credentials will be verified, though this 5482 is a no-op for anonymous credentials. 5483 5484 The dir parameter tells QEMU where to find the credential files. 5485 For server endpoints, this directory may contain a file 5486 dh-params.pem providing diffie-hellman parameters to use for the 5487 TLS server. If the file is missing, QEMU will generate a set of 5488 DH parameters at startup. This is a computationally expensive 5489 operation that consumes random pool entropy, so it is 5490 recommended that a persistent set of parameters be generated 5491 upfront and saved. 5492 5493 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5494 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5495 can be used to provide TLS support on network backends. The 5496 ``id`` parameter is a unique ID which network backends will use 5497 to access the credentials. The ``endpoint`` is either ``server`` 5498 or ``client`` depending on whether the QEMU network backend that 5499 uses the credentials will be acting as a client or as a server. 5500 For clients only, ``username`` is the username which will be 5501 sent to the server. If omitted it defaults to "qemu". 5502 5503 The dir parameter tells QEMU where to find the keys file. It is 5504 called "dir/keys.psk" and contains "username:key" pairs. This 5505 file can most easily be created using the GnuTLS ``psktool`` 5506 program. 5507 5508 For server endpoints, dir may also contain a file dh-params.pem 5509 providing diffie-hellman parameters to use for the TLS server. 5510 If the file is missing, QEMU will generate a set of DH 5511 parameters at startup. This is a computationally expensive 5512 operation that consumes random pool entropy, so it is 5513 recommended that a persistent set of parameters be generated up 5514 front and saved. 5515 5516 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5517 Creates a TLS anonymous credentials object, which can be used to 5518 provide TLS support on network backends. The ``id`` parameter is 5519 a unique ID which network backends will use to access the 5520 credentials. The ``endpoint`` is either ``server`` or ``client`` 5521 depending on whether the QEMU network backend that uses the 5522 credentials will be acting as a client or as a server. If 5523 ``verify-peer`` is enabled (the default) then once the handshake 5524 is completed, the peer credentials will be verified. With x509 5525 certificates, this implies that the clients must be provided 5526 with valid client certificates too. 5527 5528 The dir parameter tells QEMU where to find the credential files. 5529 For server endpoints, this directory may contain a file 5530 dh-params.pem providing diffie-hellman parameters to use for the 5531 TLS server. If the file is missing, QEMU will generate a set of 5532 DH parameters at startup. This is a computationally expensive 5533 operation that consumes random pool entropy, so it is 5534 recommended that a persistent set of parameters be generated 5535 upfront and saved. 5536 5537 For x509 certificate credentials the directory will contain 5538 further files providing the x509 certificates. The certificates 5539 must be stored in PEM format, in filenames ca-cert.pem, 5540 ca-crl.pem (optional), server-cert.pem (only servers), 5541 server-key.pem (only servers), client-cert.pem (only clients), 5542 and client-key.pem (only clients). 5543 5544 For the server-key.pem and client-key.pem files which contain 5545 sensitive private keys, it is possible to use an encrypted 5546 version by providing the passwordid parameter. This provides the 5547 ID of a previously created ``secret`` object containing the 5548 password for decryption. 5549 5550 The priority parameter allows to override the global default 5551 priority used by gnutls. This can be useful if the system 5552 administrator needs to use a weaker set of crypto priorities for 5553 QEMU without potentially forcing the weakness onto all 5554 applications. Or conversely if one wants wants a stronger 5555 default for QEMU than for all other applications, they can do 5556 this through this parameter. Its format is a gnutls priority 5557 string as described at 5558 https://gnutls.org/manual/html_node/Priority-Strings.html. 5559 5560 ``-object tls-cipher-suites,id=id,priority=priority`` 5561 Creates a TLS cipher suites object, which can be used to control 5562 the TLS cipher/protocol algorithms that applications are permitted 5563 to use. 5564 5565 The ``id`` parameter is a unique ID which frontends will use to 5566 access the ordered list of permitted TLS cipher suites from the 5567 host. 5568 5569 The ``priority`` parameter allows to override the global default 5570 priority used by gnutls. This can be useful if the system 5571 administrator needs to use a weaker set of crypto priorities for 5572 QEMU without potentially forcing the weakness onto all 5573 applications. Or conversely if one wants wants a stronger 5574 default for QEMU than for all other applications, they can do 5575 this through this parameter. Its format is a gnutls priority 5576 string as described at 5577 https://gnutls.org/manual/html_node/Priority-Strings.html. 5578 5579 An example of use of this object is to control UEFI HTTPS Boot. 5580 The tls-cipher-suites object exposes the ordered list of permitted 5581 TLS cipher suites from the host side to the guest firmware, via 5582 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5583 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5584 guest-side TLS. 5585 5586 In the following example, the priority at which the host-side policy 5587 is retrieved is given by the ``priority`` property. 5588 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5589 refer to /etc/crypto-policies/back-ends/gnutls.config. 5590 5591 .. parsed-literal:: 5592 5593 # |qemu_system| \\ 5594 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5595 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5596 5597 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5598 Interval t can't be 0, this filter batches the packet delivery: 5599 all packets arriving in a given interval on netdev netdevid are 5600 delayed until the end of the interval. Interval is in 5601 microseconds. ``status`` is optional that indicate whether the 5602 netfilter is on (enabled) or off (disabled), the default status 5603 for netfilter will be 'on'. 5604 5605 queue all\|rx\|tx is an option that can be applied to any 5606 netfilter. 5607 5608 ``all``: the filter is attached both to the receive and the 5609 transmit queue of the netdev (default). 5610 5611 ``rx``: the filter is attached to the receive queue of the 5612 netdev, where it will receive packets sent to the netdev. 5613 5614 ``tx``: the filter is attached to the transmit queue of the 5615 netdev, where it will receive packets sent by the netdev. 5616 5617 position head\|tail\|id=<id> is an option to specify where the 5618 filter should be inserted in the filter list. It can be applied 5619 to any netfilter. 5620 5621 ``head``: the filter is inserted at the head of the filter list, 5622 before any existing filters. 5623 5624 ``tail``: the filter is inserted at the tail of the filter list, 5625 behind any existing filters (default). 5626 5627 ``id=<id>``: the filter is inserted before or behind the filter 5628 specified by <id>, see the insert option below. 5629 5630 insert behind\|before is an option to specify where to insert 5631 the new filter relative to the one specified with 5632 position=id=<id>. It can be applied to any netfilter. 5633 5634 ``before``: insert before the specified filter. 5635 5636 ``behind``: insert behind the specified filter (default). 5637 5638 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5639 filter-mirror on netdev netdevid,mirror net packet to 5640 chardevchardevid, if it has the vnet\_hdr\_support flag, 5641 filter-mirror will mirror packet with vnet\_hdr\_len. 5642 5643 ``-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]`` 5644 filter-redirector on netdev netdevid,redirect filter's net 5645 packet to chardev chardevid,and redirect indev's packet to 5646 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5647 will redirect packet with vnet\_hdr\_len. Create a 5648 filter-redirector we need to differ outdev id from indev id, id 5649 can not be the same. we can just use indev or outdev, but at 5650 least one of indev or outdev need to be specified. 5651 5652 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5653 Filter-rewriter is a part of COLO project.It will rewrite tcp 5654 packet to secondary from primary to keep secondary tcp 5655 connection,and rewrite tcp packet to primary from secondary make 5656 tcp packet can be handled by client.if it has the 5657 vnet\_hdr\_support flag, we can parse packet with vnet header. 5658 5659 usage: colo secondary: -object 5660 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5661 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5662 filter-rewriter,id=rew0,netdev=hn0,queue=all 5663 5664 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5665 Dump the network traffic on netdev dev to the file specified by 5666 filename. At most len bytes (64k by default) per packet are 5667 stored. The file format is libpcap, so it can be analyzed with 5668 tools such as tcpdump or Wireshark. 5669 5670 ``-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}]`` 5671 Colo-compare gets packet from primary\_in chardevid and 5672 secondary\_in, then compare whether the payload of primary packet 5673 and secondary packet are the same. If same, it will output 5674 primary packet to out\_dev, else it will notify COLO-framework to do 5675 checkpoint and send primary packet to out\_dev. In order to 5676 improve efficiency, we need to put the task of comparison in 5677 another iothread. If it has the vnet\_hdr\_support flag, 5678 colo compare will send/recv packet with vnet\_hdr\_len. 5679 The compare\_timeout=@var{ms} determines the maximum time of the 5680 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5681 is to set the period of scanning expired primary node network packets. 5682 The max\_queue\_size=@var{size} is to set the max compare queue 5683 size depend on user environment. 5684 If user want to use Xen COLO, need to add the notify\_dev to 5685 notify Xen colo-frame to do checkpoint. 5686 5687 COLO-compare must be used with the help of filter-mirror, 5688 filter-redirector and filter-rewriter. 5689 5690 :: 5691 5692 KVM COLO 5693 5694 primary: 5695 -netdev tap,id=hn0,vhost=off 5696 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5697 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5698 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5699 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5700 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5701 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5702 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5703 -object iothread,id=iothread1 5704 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5705 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5706 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5707 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5708 5709 secondary: 5710 -netdev tap,id=hn0,vhost=off 5711 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5712 -chardev socket,id=red0,host=3.3.3.3,port=9003 5713 -chardev socket,id=red1,host=3.3.3.3,port=9004 5714 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5715 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5716 5717 5718 Xen COLO 5719 5720 primary: 5721 -netdev tap,id=hn0,vhost=off 5722 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5723 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5724 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5725 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5726 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5727 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5728 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5729 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5730 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5731 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5732 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5733 -object iothread,id=iothread1 5734 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5735 5736 secondary: 5737 -netdev tap,id=hn0,vhost=off 5738 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5739 -chardev socket,id=red0,host=3.3.3.3,port=9003 5740 -chardev socket,id=red1,host=3.3.3.3,port=9004 5741 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5742 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5743 5744 If you want to know the detail of above command line, you can 5745 read the colo-compare git log. 5746 5747 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5748 Creates a cryptodev backend which executes crypto operations from 5749 the QEMU cipher APIs. The id parameter is a unique ID that will 5750 be used to reference this cryptodev backend from the 5751 ``virtio-crypto`` device. The queues parameter is optional, 5752 which specify the queue number of cryptodev backend, the default 5753 of queues is 1. 5754 5755 .. parsed-literal:: 5756 5757 # |qemu_system| \\ 5758 [...] \\ 5759 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5760 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5761 [...] 5762 5763 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5764 Creates a vhost-user cryptodev backend, backed by a chardev 5765 chardevid. The id parameter is a unique ID that will be used to 5766 reference this cryptodev backend from the ``virtio-crypto`` 5767 device. The chardev should be a unix domain socket backed one. 5768 The vhost-user uses a specifically defined protocol to pass 5769 vhost ioctl replacement messages to an application on the other 5770 end of the socket. The queues parameter is optional, which 5771 specify the queue number of cryptodev backend for multiqueue 5772 vhost-user, the default of queues is 1. 5773 5774 .. parsed-literal:: 5775 5776 # |qemu_system| \\ 5777 [...] \\ 5778 -chardev socket,id=chardev0,path=/path/to/socket \\ 5779 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5780 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5781 [...] 5782 5783 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5784 \ 5785 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5786 Defines a secret to store a password, encryption key, or some 5787 other sensitive data. The sensitive data can either be passed 5788 directly via the data parameter, or indirectly via the file 5789 parameter. Using the data parameter is insecure unless the 5790 sensitive data is encrypted. 5791 5792 The sensitive data can be provided in raw format (the default), 5793 or base64. When encoded as JSON, the raw format only supports 5794 valid UTF-8 characters, so base64 is recommended for sending 5795 binary data. QEMU will convert from which ever format is 5796 provided to the format it needs internally. eg, an RBD password 5797 can be provided in raw format, even though it will be base64 5798 encoded when passed onto the RBD sever. 5799 5800 For added protection, it is possible to encrypt the data 5801 associated with a secret using the AES-256-CBC cipher. Use of 5802 encryption is indicated by providing the keyid and iv 5803 parameters. The keyid parameter provides the ID of a previously 5804 defined secret that contains the AES-256 decryption key. This 5805 key should be 32-bytes long and be base64 encoded. The iv 5806 parameter provides the random initialization vector used for 5807 encryption of this particular secret and should be a base64 5808 encrypted string of the 16-byte IV. 5809 5810 The simplest (insecure) usage is to provide the secret inline 5811 5812 .. parsed-literal:: 5813 5814 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5815 5816 The simplest secure usage is to provide the secret via a file 5817 5818 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5819 secret,id=sec0,file=mypasswd.txt,format=raw 5820 5821 For greater security, AES-256-CBC should be used. To illustrate 5822 usage, consider the openssl command line tool which can encrypt 5823 the data. Note that when encrypting, the plaintext must be 5824 padded to the cipher block size (32 bytes) using the standard 5825 PKCS#5/6 compatible padding algorithm. 5826 5827 First a master key needs to be created in base64 encoding: 5828 5829 :: 5830 5831 # openssl rand -base64 32 > key.b64 5832 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5833 5834 Each secret to be encrypted needs to have a random 5835 initialization vector generated. These do not need to be kept 5836 secret 5837 5838 :: 5839 5840 # openssl rand -base64 16 > iv.b64 5841 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5842 5843 The secret to be defined can now be encrypted, in this case 5844 we're telling openssl to base64 encode the result, but it could 5845 be left as raw bytes if desired. 5846 5847 :: 5848 5849 # SECRET=$(printf "letmein" | 5850 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5851 5852 When launching QEMU, create a master secret pointing to 5853 ``key.b64`` and specify that to be used to decrypt the user 5854 password. Pass the contents of ``iv.b64`` to the second secret 5855 5856 .. parsed-literal:: 5857 5858 # |qemu_system| \\ 5859 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5860 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5861 data=$SECRET,iv=$(<iv.b64) 5862 5863 ``-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]`` 5864 Create a Secure Encrypted Virtualization (SEV) guest object, 5865 which can be used to provide the guest memory encryption support 5866 on AMD processors. 5867 5868 When memory encryption is enabled, one of the physical address 5869 bit (aka the C-bit) is utilized to mark if a memory page is 5870 protected. The ``cbitpos`` is used to provide the C-bit 5871 position. The C-bit position is Host family dependent hence user 5872 must provide this value. On EPYC, the value should be 47. 5873 5874 When memory encryption is enabled, we loose certain bits in 5875 physical address space. The ``reduced-phys-bits`` is used to 5876 provide the number of bits we loose in physical address space. 5877 Similar to C-bit, the value is Host family dependent. On EPYC, 5878 a guest will lose a maximum of 1 bit, so the value should be 1. 5879 5880 The ``sev-device`` provides the device file to use for 5881 communicating with the SEV firmware running inside AMD Secure 5882 Processor. The default device is '/dev/sev'. If hardware 5883 supports memory encryption then /dev/sev devices are created by 5884 CCP driver. 5885 5886 The ``policy`` provides the guest policy to be enforced by the 5887 SEV firmware and restrict what configuration and operational 5888 commands can be performed on this guest by the hypervisor. The 5889 policy should be provided by the guest owner and is bound to the 5890 guest and cannot be changed throughout the lifetime of the 5891 guest. The default is 0. 5892 5893 If guest ``policy`` allows sharing the key with another SEV 5894 guest then ``handle`` can be use to provide handle of the guest 5895 from which to share the key. 5896 5897 The ``dh-cert-file`` and ``session-file`` provides the guest 5898 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5899 and session parameters are used for establishing a cryptographic 5900 session with the guest owner to negotiate keys used for 5901 attestation. The file must be encoded in base64. 5902 5903 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5904 cmdline to a designated guest firmware page for measured Linux 5905 boot with -kernel. The default is off. (Since 6.2) 5906 5907 e.g to launch a SEV guest 5908 5909 .. parsed-literal:: 5910 5911 # |qemu_system_x86| \\ 5912 ...... \\ 5913 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5914 -machine ...,memory-encryption=sev0 \\ 5915 ..... 5916 5917 ``-object authz-simple,id=id,identity=string`` 5918 Create an authorization object that will control access to 5919 network services. 5920 5921 The ``identity`` parameter is identifies the user and its format 5922 depends on the network service that authorization object is 5923 associated with. For authorizing based on TLS x509 certificates, 5924 the identity must be the x509 distinguished name. Note that care 5925 must be taken to escape any commas in the distinguished name. 5926 5927 An example authorization object to validate a x509 distinguished 5928 name would look like: 5929 5930 .. parsed-literal:: 5931 5932 # |qemu_system| \\ 5933 ... \\ 5934 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5935 ... 5936 5937 Note the use of quotes due to the x509 distinguished name 5938 containing whitespace, and escaping of ','. 5939 5940 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5941 Create an authorization object that will control access to 5942 network services. 5943 5944 The ``filename`` parameter is the fully qualified path to a file 5945 containing the access control list rules in JSON format. 5946 5947 An example set of rules that match against SASL usernames might 5948 look like: 5949 5950 :: 5951 5952 { 5953 "rules": [ 5954 { "match": "fred", "policy": "allow", "format": "exact" }, 5955 { "match": "bob", "policy": "allow", "format": "exact" }, 5956 { "match": "danb", "policy": "deny", "format": "glob" }, 5957 { "match": "dan*", "policy": "allow", "format": "exact" }, 5958 ], 5959 "policy": "deny" 5960 } 5961 5962 When checking access the object will iterate over all the rules 5963 and the first rule to match will have its ``policy`` value 5964 returned as the result. If no rules match, then the default 5965 ``policy`` value is returned. 5966 5967 The rules can either be an exact string match, or they can use 5968 the simple UNIX glob pattern matching to allow wildcards to be 5969 used. 5970 5971 If ``refresh`` is set to true the file will be monitored and 5972 automatically reloaded whenever its content changes. 5973 5974 As with the ``authz-simple`` object, the format of the identity 5975 strings being matched depends on the network service, but is 5976 usually a TLS x509 distinguished name, or a SASL username. 5977 5978 An example authorization object to validate a SASL username 5979 would look like: 5980 5981 .. parsed-literal:: 5982 5983 # |qemu_system| \\ 5984 ... \\ 5985 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5986 ... 5987 5988 ``-object authz-pam,id=id,service=string`` 5989 Create an authorization object that will control access to 5990 network services. 5991 5992 The ``service`` parameter provides the name of a PAM service to 5993 use for authorization. It requires that a file 5994 ``/etc/pam.d/service`` exist to provide the configuration for 5995 the ``account`` subsystem. 5996 5997 An example authorization object to validate a TLS x509 5998 distinguished name would look like: 5999 6000 .. parsed-literal:: 6001 6002 # |qemu_system| \\ 6003 ... \\ 6004 -object authz-pam,id=auth0,service=qemu-vnc \\ 6005 ... 6006 6007 There would then be a corresponding config file for PAM at 6008 ``/etc/pam.d/qemu-vnc`` that contains: 6009 6010 :: 6011 6012 account requisite pam_listfile.so item=user sense=allow \ 6013 file=/etc/qemu/vnc.allow 6014 6015 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 6016 of x509 distinguished names that are permitted access 6017 6018 :: 6019 6020 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 6021 6022 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 6023 Creates a dedicated event loop thread that devices can be 6024 assigned to. This is known as an IOThread. By default device 6025 emulation happens in vCPU threads or the main event loop thread. 6026 This can become a scalability bottleneck. IOThreads allow device 6027 emulation and I/O to run on other host CPUs. 6028 6029 The ``id`` parameter is a unique ID that will be used to 6030 reference this IOThread from ``-device ...,iothread=id``. 6031 Multiple devices can be assigned to an IOThread. Note that not 6032 all devices support an ``iothread`` parameter. 6033 6034 The ``query-iothreads`` QMP command lists IOThreads and reports 6035 their thread IDs so that the user can configure host CPU 6036 pinning/affinity. 6037 6038 IOThreads use an adaptive polling algorithm to reduce event loop 6039 latency. Instead of entering a blocking system call to monitor 6040 file descriptors and then pay the cost of being woken up when an 6041 event occurs, the polling algorithm spins waiting for events for 6042 a short time. The algorithm's default parameters are suitable 6043 for many cases but can be adjusted based on knowledge of the 6044 workload and/or host device latency. 6045 6046 The ``poll-max-ns`` parameter is the maximum number of 6047 nanoseconds to busy wait for events. Polling can be disabled by 6048 setting this value to 0. 6049 6050 The ``poll-grow`` parameter is the multiplier used to increase 6051 the polling time when the algorithm detects it is missing events 6052 due to not polling long enough. 6053 6054 The ``poll-shrink`` parameter is the divisor used to decrease 6055 the polling time when the algorithm detects it is spending too 6056 long polling without encountering events. 6057 6058 The ``aio-max-batch`` parameter is the maximum number of requests 6059 in a batch for the AIO engine, 0 means that the engine will use 6060 its default. 6061 6062 The IOThread parameters can be modified at run-time using the 6063 ``qom-set`` command (where ``iothread1`` is the IOThread's 6064 ``id``): 6065 6066 :: 6067 6068 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 6069ERST 6070 6071 6072HXCOMM This is the last statement. Insert new options before this line! 6073 6074#undef DEF 6075#undef DEFHEADING 6076#undef ARCHHEADING 6077
