1HXCOMM See docs/devel/docs.rst for the format of this file. 2HXCOMM 3HXCOMM Use DEFHEADING() to define headings in both help text and rST. 4HXCOMM Text between SRST and ERST is copied to the rST version and 5HXCOMM discarded from C version. 6HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 7HXCOMM construct option structures, enums and help message for specified 8HXCOMM architectures. 9HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 10 11DEFHEADING(Standard options:) 12 13DEF("help", 0, QEMU_OPTION_h, 14 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 15SRST 16``-h`` 17 Display help and exit 18ERST 19 20DEF("version", 0, QEMU_OPTION_version, 21 "-version display version information and exit\n", QEMU_ARCH_ALL) 22SRST 23``-version`` 24 Display version information and exit 25ERST 26 27DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 28 "-machine [type=]name[,prop[=value][,...]]\n" 29 " selects emulated machine ('-machine help' for list)\n" 30 " property accel=accel1[:accel2[:...]] selects accelerator\n" 31 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 32 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 33 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 34 " mem-merge=on|off controls memory merge support (default: on)\n" 35 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 36 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 37 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 38 " nvdimm=on|off controls NVDIMM support (default=off)\n" 39 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 40 " hmat=on|off controls ACPI HMAT support (default=off)\n" 41 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 42 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 43 QEMU_ARCH_ALL) 44SRST 45``-machine [type=]name[,prop=value[,...]]`` 46 Select the emulated machine by name. Use ``-machine help`` to list 47 available machines. 48 49 For architectures which aim to support live migration compatibility 50 across releases, each release will introduce a new versioned machine 51 type. For example, the 2.8.0 release introduced machine types 52 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 53 54 To allow live migration of guests from QEMU version 2.8.0, to QEMU 55 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 56 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 57 skip multiple intermediate releases when upgrading, new releases of 58 QEMU will support machine types from many previous versions. 59 60 Supported machine properties are: 61 62 ``accel=accels1[:accels2[:...]]`` 63 This is used to enable an accelerator. Depending on the target 64 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 65 By default, tcg is used. If there is more than one accelerator 66 specified, the next one is used if the previous one fails to 67 initialize. 68 69 ``vmport=on|off|auto`` 70 Enables emulation of VMWare IO port, for vmmouse etc. auto says 71 to select the value based on accel. For accel=xen the default is 72 off otherwise the default is on. 73 74 ``dump-guest-core=on|off`` 75 Include guest memory in a core dump. The default is on. 76 77 ``mem-merge=on|off`` 78 Enables or disables memory merge support. This feature, when 79 supported by the host, de-duplicates identical memory pages 80 among VMs instances (enabled by default). 81 82 ``aes-key-wrap=on|off`` 83 Enables or disables AES key wrapping support on s390-ccw hosts. 84 This feature controls whether AES wrapping keys will be created 85 to allow execution of AES cryptographic functions. The default 86 is on. 87 88 ``dea-key-wrap=on|off`` 89 Enables or disables DEA key wrapping support on s390-ccw hosts. 90 This feature controls whether DEA wrapping keys will be created 91 to allow execution of DEA cryptographic functions. The default 92 is on. 93 94 ``nvdimm=on|off`` 95 Enables or disables NVDIMM support. The default is off. 96 97 ``memory-encryption=`` 98 Memory encryption object to use. The default is none. 99 100 ``hmat=on|off`` 101 Enables or disables ACPI Heterogeneous Memory Attribute Table 102 (HMAT) support. The default is off. 103 104 ``memory-backend='id'`` 105 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 106 Allows to use a memory backend as main RAM. 107 108 For example: 109 :: 110 111 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 112 -machine memory-backend=pc.ram 113 -m 512M 114 115 Migration compatibility note: 116 117 * as backend id one shall use value of 'default-ram-id', advertised by 118 machine type (available via ``query-machines`` QMP command), if migration 119 to/from old QEMU (<5.0) is expected. 120 * for machine types 4.0 and older, user shall 121 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 122 if migration to/from old QEMU (<5.0) is expected. 123 124 For example: 125 :: 126 127 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 128 -machine memory-backend=pc.ram 129 -m 512M 130 131 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 132 Define a CXL Fixed Memory Window (CFMW). 133 134 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 135 136 They are regions of Host Physical Addresses (HPA) on a system which 137 may be interleaved across one or more CXL host bridges. The system 138 software will assign particular devices into these windows and 139 configure the downstream Host-managed Device Memory (HDM) decoders 140 in root ports, switch ports and devices appropriately to meet the 141 interleave requirements before enabling the memory devices. 142 143 ``targets.X=target`` provides the mapping to CXL host bridges 144 which may be identified by the id provided in the -device entry. 145 Multiple entries are needed to specify all the targets when 146 the fixed memory window represents interleaved memory. X is the 147 target index from 0. 148 149 ``size=size`` sets the size of the CFMW. This must be a multiple of 150 256MiB. The region will be aligned to 256MiB but the location is 151 platform and configuration dependent. 152 153 ``interleave-granularity=granularity`` sets the granularity of 154 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 155 4096KiB, 8192KiB and 16384KiB granularities supported. 156 157 Example: 158 159 :: 160 161 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 162ERST 163 164DEF("M", HAS_ARG, QEMU_OPTION_M, 165 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 166 QEMU_ARCH_ALL) 167 168SRST 169``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 170 Define an SGX EPC section. 171ERST 172 173DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 174 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 175SRST 176``-cpu model`` 177 Select CPU model (``-cpu help`` for list and additional feature 178 selection) 179ERST 180 181DEF("accel", HAS_ARG, QEMU_OPTION_accel, 182 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 183 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 184 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 185 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 186 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 187 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 188 " split-wx=on|off (enable TCG split w^x mapping)\n" 189 " tb-size=n (TCG translation block cache size)\n" 190 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 191 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 192 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 193 " thread=single|multi (enable multi-threaded TCG)\n" 194 " device=path (KVM device path, default /dev/kvm)\n", QEMU_ARCH_ALL) 195SRST 196``-accel name[,prop=value[,...]]`` 197 This is used to enable an accelerator. Depending on the target 198 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 199 default, tcg is used. If there is more than one accelerator 200 specified, the next one is used if the previous one fails to 201 initialize. 202 203 ``igd-passthru=on|off`` 204 When Xen is in use, this option controls whether Intel 205 integrated graphics devices can be passed through to the guest 206 (default=off) 207 208 ``kernel-irqchip=on|off|split`` 209 Controls KVM in-kernel irqchip support. The default is full 210 acceleration of the interrupt controllers. On x86, split irqchip 211 reduces the kernel attack surface, at a performance cost for 212 non-MSI interrupts. Disabling the in-kernel irqchip completely 213 is not recommended except for debugging purposes. 214 215 ``kvm-shadow-mem=size`` 216 Defines the size of the KVM shadow MMU. 217 218 ``one-insn-per-tb=on|off`` 219 Makes the TCG accelerator put only one guest instruction into 220 each translation block. This slows down emulation a lot, but 221 can be useful in some situations, such as when trying to analyse 222 the logs produced by the ``-d`` option. 223 224 ``split-wx=on|off`` 225 Controls the use of split w^x mapping for the TCG code generation 226 buffer. Some operating systems require this to be enabled, and in 227 such a case this will default on. On other operating systems, this 228 will default off, but one may enable this for testing or debugging. 229 230 ``tb-size=n`` 231 Controls the size (in MiB) of the TCG translation block cache. 232 233 ``thread=single|multi`` 234 Controls number of TCG threads. When the TCG is multi-threaded 235 there will be one thread per vCPU therefore taking advantage of 236 additional host cores. The default is to enable multi-threading 237 where both the back-end and front-ends support it and no 238 incompatible TCG features have been enabled (e.g. 239 icount/replay). 240 241 ``dirty-ring-size=n`` 242 When the KVM accelerator is used, it controls the size of the per-vCPU 243 dirty page ring buffer (number of entries for each vCPU). It should 244 be a value that is power of two, and it should be 1024 or bigger (but 245 still less than the maximum value that the kernel supports). 4096 246 could be a good initial value if you have no idea which is the best. 247 Set this value to 0 to disable the feature. By default, this feature 248 is disabled (dirty-ring-size=0). When enabled, KVM will instead 249 record dirty pages in a bitmap. 250 251 ``eager-split-size=n`` 252 KVM implements dirty page logging at the PAGE_SIZE granularity and 253 enabling dirty-logging on a huge-page requires breaking it into 254 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 255 lazily by default. There are performance benefits in doing huge-page 256 split eagerly, especially in situations where TLBI costs associated 257 with break-before-make sequences are considerable and also if guest 258 workloads are read intensive. The size here specifies how many pages 259 to break at a time and needs to be a valid block size which is 260 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 261 respectively. Be wary of specifying a higher size as it will have an 262 impact on the memory. By default, this feature is disabled 263 (eager-split-size=0). 264 265 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 266 Enables or disables notify VM exit support on x86 host and specify 267 the corresponding notify window to trigger the VM exit if enabled. 268 ``run`` option enables the feature. It does nothing and continue 269 if the exit happens. ``internal-error`` option enables the feature. 270 It raises a internal error. ``disable`` option doesn't enable the feature. 271 This feature can mitigate the CPU stuck issue due to event windows don't 272 open up for a specified of time (i.e. notify-window). 273 Default: notify-vmexit=run,notify-window=0. 274 275 ``device=path`` 276 Sets the path to the KVM device node. Defaults to ``/dev/kvm``. This 277 option can be used to pass the KVM device to use via a file descriptor 278 by setting the value to ``/dev/fdset/NN``. 279 280ERST 281 282DEF("smp", HAS_ARG, QEMU_OPTION_smp, 283 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 284 " [,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 285 " set the number of initial CPUs to 'n' [default=1]\n" 286 " maxcpus= maximum number of total CPUs, including\n" 287 " offline CPUs for hotplug, etc\n" 288 " drawers= number of drawers on the machine board\n" 289 " books= number of books in one drawer\n" 290 " sockets= number of sockets in one book\n" 291 " dies= number of dies in one socket\n" 292 " clusters= number of clusters in one die\n" 293 " cores= number of cores in one cluster\n" 294 " threads= number of threads in one core\n" 295 "Note: Different machines may have different subsets of the CPU topology\n" 296 " parameters supported, so the actual meaning of the supported parameters\n" 297 " will vary accordingly. For example, for a machine type that supports a\n" 298 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 299 " sequentially mean as below:\n" 300 " sockets means the number of sockets on the machine board\n" 301 " cores means the number of cores in one socket\n" 302 " threads means the number of threads in one core\n" 303 " For a particular machine type board, an expected CPU topology hierarchy\n" 304 " can be defined through the supported sub-option. Unsupported parameters\n" 305 " can also be provided in addition to the sub-option, but their values\n" 306 " must be set as 1 in the purpose of correct parsing.\n", 307 QEMU_ARCH_ALL) 308SRST 309``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 310 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 311 the machine type board. On boards supporting CPU hotplug, the optional 312 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 313 added at runtime. When both parameters are omitted, the maximum number 314 of CPUs will be calculated from the provided topology members and the 315 initial CPU count will match the maximum number. When only one of them 316 is given then the omitted one will be set to its counterpart's value. 317 Both parameters may be specified, but the maximum number of CPUs must 318 be equal to or greater than the initial CPU count. Product of the 319 CPU topology hierarchy must be equal to the maximum number of CPUs. 320 Both parameters are subject to an upper limit that is determined by 321 the specific machine type chosen. 322 323 To control reporting of CPU topology information, values of the topology 324 parameters can be specified. Machines may only support a subset of the 325 parameters and different machines may have different subsets supported 326 which vary depending on capacity of the corresponding CPU targets. So 327 for a particular machine type board, an expected topology hierarchy can 328 be defined through the supported sub-option. Unsupported parameters can 329 also be provided in addition to the sub-option, but their values must be 330 set as 1 in the purpose of correct parsing. 331 332 Either the initial CPU count, or at least one of the topology parameters 333 must be specified. The specified parameters must be greater than zero, 334 explicit configuration like "cpus=0" is not allowed. Values for any 335 omitted parameters will be computed from those which are given. 336 337 For example, the following sub-option defines a CPU topology hierarchy 338 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 339 core) for a machine that only supports sockets/cores/threads. 340 Some members of the option can be omitted but their values will be 341 automatically computed: 342 343 :: 344 345 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 346 347 The following sub-option defines a CPU topology hierarchy (2 sockets 348 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 349 per core) for PC machines which support sockets/dies/cores/threads. 350 Some members of the option can be omitted but their values will be 351 automatically computed: 352 353 :: 354 355 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 356 357 The following sub-option defines a CPU topology hierarchy (2 sockets 358 totally on the machine, 2 clusters per socket, 2 cores per cluster, 359 2 threads per core) for ARM virt machines which support sockets/clusters 360 /cores/threads. Some members of the option can be omitted but their values 361 will be automatically computed: 362 363 :: 364 365 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 366 367 Historically preference was given to the coarsest topology parameters 368 when computing missing values (ie sockets preferred over cores, which 369 were preferred over threads), however, this behaviour is considered 370 liable to change. Prior to 6.2 the preference was sockets over cores 371 over threads. Since 6.2 the preference is cores over sockets over threads. 372 373 For example, the following option defines a machine board with 2 sockets 374 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 375 376 :: 377 378 -smp 2 379 380 Note: The cluster topology will only be generated in ACPI and exposed 381 to guest if it's explicitly specified in -smp. 382ERST 383 384DEF("numa", HAS_ARG, QEMU_OPTION_numa, 385 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 386 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 387 "-numa dist,src=source,dst=destination,val=distance\n" 388 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 389 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 390 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 391 QEMU_ARCH_ALL) 392SRST 393``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 394 \ 395``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 396 \ 397``-numa dist,src=source,dst=destination,val=distance`` 398 \ 399``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 400 \ 401``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 402 \ 403``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 404 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 405 distance from a source node to a destination node. Set the ACPI 406 Heterogeneous Memory Attributes for the given nodes. 407 408 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 409 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 410 contiguous range of CPU indexes (or a single VCPU if lastcpu is 411 omitted). A non-contiguous set of VCPUs can be represented by 412 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 413 omitted on all nodes, VCPUs are automatically split between them. 414 415 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 416 NUMA node: 417 418 :: 419 420 -numa node,cpus=0-2,cpus=5 421 422 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 423 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 424 assign CPU objects to a node using topology layout properties of 425 CPU. The set of properties is machine specific, and depends on used 426 machine type/'\ ``smp``\ ' options. It could be queried with 427 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 428 property specifies node to which CPU object will be assigned, it's 429 required for node to be declared with '\ ``node``\ ' option before 430 it's used with '\ ``cpu``\ ' option. 431 432 For example: 433 434 :: 435 436 -M pc \ 437 -smp 1,sockets=2,maxcpus=2 \ 438 -numa node,nodeid=0 -numa node,nodeid=1 \ 439 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 440 441 '\ ``memdev``\ ' option assigns RAM from a given memory backend 442 device to a node. It is recommended to use '\ ``memdev``\ ' option 443 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 444 option provides better performance and more control over the 445 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 446 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 447 448 For compatibility reasons, legacy '\ ``mem``\ ' option is 449 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 450 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 451 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 452 option, and vice versa. 453 454 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 455 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 456 for '\ ``-numa node``\ ' without memory specified was removed. 457 458 '\ ``initiator``\ ' is an additional option that points to an 459 initiator NUMA node that has best performance (the lowest latency or 460 largest bandwidth) to this NUMA node. Note that this option can be 461 set only when the machine property 'hmat' is set to 'on'. 462 463 Following example creates a machine with 2 NUMA nodes, node 0 has 464 CPU. node 1 has only memory, and its initiator is node 0. Note that 465 because node 0 has CPU, by default the initiator of node 0 is itself 466 and must be itself. 467 468 :: 469 470 -machine hmat=on \ 471 -m 2G,slots=2,maxmem=4G \ 472 -object memory-backend-ram,size=1G,id=m0 \ 473 -object memory-backend-ram,size=1G,id=m1 \ 474 -numa node,nodeid=0,memdev=m0 \ 475 -numa node,nodeid=1,memdev=m1,initiator=0 \ 476 -smp 2,sockets=2,maxcpus=2 \ 477 -numa cpu,node-id=0,socket-id=0 \ 478 -numa cpu,node-id=0,socket-id=1 479 480 source and destination are NUMA node IDs. distance is the NUMA 481 distance from source to destination. The distance from a node to 482 itself is always 10. If any pair of nodes is given a distance, then 483 all pairs must be given distances. Although, when distances are only 484 given in one direction for each pair of nodes, then the distances in 485 the opposite directions are assumed to be the same. If, however, an 486 asymmetrical pair of distances is given for even one node pair, then 487 all node pairs must be provided distance values for both directions, 488 even when they are symmetrical. When a node is unreachable from 489 another node, set the pair's distance to 255. 490 491 Note that the -``numa`` option doesn't allocate any of the specified 492 resources, it just assigns existing resources to NUMA nodes. This 493 means that one still has to use the ``-m``, ``-smp`` options to 494 allocate RAM and VCPUs respectively. 495 496 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 497 Information between initiator and target NUMA nodes in ACPI 498 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 499 create memory requests, usually it has one or more processors. 500 Target NUMA node contains addressable memory. 501 502 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 503 the memory hierarchy of the target NUMA node: if hierarchy is 504 'memory', the structure represents the memory performance; if 505 hierarchy is 'first-level\|second-level\|third-level', this 506 structure represents aggregated performance of memory side caches 507 for each domain. type of 'data-type' is type of data represented by 508 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 509 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 510 the target memory; if 'hierarchy' is 511 'first-level\|second-level\|third-level', 'data-type' is 512 'access\|read\|write' hit latency or 'access\|read\|write' hit 513 bandwidth of the target memory side cache. 514 515 lat is latency value in nanoseconds. bw is bandwidth value, the 516 possible value and units are NUM[M\|G\|T], mean that the bandwidth 517 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 518 used suffix). Note that if latency or bandwidth value is 0, means 519 the corresponding latency or bandwidth information is not provided. 520 521 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 522 belongs. size is the size of memory side cache in bytes. level is 523 the cache level described in this structure, note that the cache 524 level 0 should not be used with '\ ``hmat-cache``\ ' option. 525 associativity is the cache associativity, the possible value is 526 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 527 is the write policy. line is the cache Line size in bytes. 528 529 For example, the following options describe 2 NUMA nodes. Node 0 has 530 2 cpus and a ram, node 1 has only a ram. The processors in node 0 531 access memory in node 0 with access-latency 5 nanoseconds, 532 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 533 memory in NUMA node 1 with access-latency 10 nanoseconds, 534 access-bandwidth is 100 MB/s. And for memory side cache information, 535 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 536 policy is write-back, the cache Line size is 8 bytes: 537 538 :: 539 540 -machine hmat=on \ 541 -m 2G \ 542 -object memory-backend-ram,size=1G,id=m0 \ 543 -object memory-backend-ram,size=1G,id=m1 \ 544 -smp 2,sockets=2,maxcpus=2 \ 545 -numa node,nodeid=0,memdev=m0 \ 546 -numa node,nodeid=1,memdev=m1,initiator=0 \ 547 -numa cpu,node-id=0,socket-id=0 \ 548 -numa cpu,node-id=0,socket-id=1 \ 549 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 550 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 551 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 552 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 553 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 554 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 555ERST 556 557DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 558 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 559 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 560SRST 561``-add-fd fd=fd,set=set[,opaque=opaque]`` 562 Add a file descriptor to an fd set. Valid options are: 563 564 ``fd=fd`` 565 This option defines the file descriptor of which a duplicate is 566 added to fd set. The file descriptor cannot be stdin, stdout, or 567 stderr. 568 569 ``set=set`` 570 This option defines the ID of the fd set to add the file 571 descriptor to. 572 573 ``opaque=opaque`` 574 This option defines a free-form string that can be used to 575 describe fd. 576 577 You can open an image using pre-opened file descriptors from an fd 578 set: 579 580 .. parsed-literal:: 581 582 |qemu_system| \\ 583 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 584 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 585 -drive file=/dev/fdset/2,index=0,media=disk 586ERST 587 588DEF("set", HAS_ARG, QEMU_OPTION_set, 589 "-set group.id.arg=value\n" 590 " set <arg> parameter for item <id> of type <group>\n" 591 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 592SRST 593``-set group.id.arg=value`` 594 Set parameter arg for item id of type group 595ERST 596 597DEF("global", HAS_ARG, QEMU_OPTION_global, 598 "-global driver.property=value\n" 599 "-global driver=driver,property=property,value=value\n" 600 " set a global default for a driver property\n", 601 QEMU_ARCH_ALL) 602SRST 603``-global driver.prop=value`` 604 \ 605``-global driver=driver,property=property,value=value`` 606 Set default value of driver's property prop to value, e.g.: 607 608 .. parsed-literal:: 609 610 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 611 612 In particular, you can use this to set driver properties for devices 613 which are created automatically by the machine model. To create a 614 device which is not created automatically and set properties on it, 615 use -``device``. 616 617 -global driver.prop=value is shorthand for -global 618 driver=driver,property=prop,value=value. The longhand syntax works 619 even when driver contains a dot. 620ERST 621 622DEF("boot", HAS_ARG, QEMU_OPTION_boot, 623 "-boot [order=drives][,once=drives][,menu=on|off]\n" 624 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 625 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 626 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 627 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 628 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 629 QEMU_ARCH_ALL) 630SRST 631``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 632 Specify boot order drives as a string of drive letters. Valid drive 633 letters depend on the target architecture. The x86 PC uses: a, b 634 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 635 (Etherboot from network adapter 1-4), hard disk boot is the default. 636 To apply a particular boot order only on the first startup, specify 637 it via ``once``. Note that the ``order`` or ``once`` parameter 638 should not be used together with the ``bootindex`` property of 639 devices, since the firmware implementations normally do not support 640 both at the same time. 641 642 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 643 as firmware/BIOS supports them. The default is non-interactive boot. 644 645 A splash picture could be passed to bios, enabling user to show it 646 as logo, when option splash=sp\_name is given and menu=on, If 647 firmware/BIOS supports them. Currently Seabios for X86 system 648 support it. limitation: The splash file could be a jpeg file or a 649 BMP file in 24 BPP format(true color). The resolution should be 650 supported by the SVGA mode, so the recommended is 320x240, 640x480, 651 800x640. 652 653 A timeout could be passed to bios, guest will pause for rb\_timeout 654 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 655 not reboot, qemu passes '-1' to bios by default. Currently Seabios 656 for X86 system support it. 657 658 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 659 it. This only effects when boot priority is changed by bootindex 660 options. The default is non-strict boot. 661 662 .. parsed-literal:: 663 664 # try to boot from network first, then from hard disk 665 |qemu_system_x86| -boot order=nc 666 # boot from CD-ROM first, switch back to default order after reboot 667 |qemu_system_x86| -boot once=d 668 # boot with a splash picture for 5 seconds. 669 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 670 671 Note: The legacy format '-boot drives' is still supported but its 672 use is discouraged as it may be removed from future versions. 673ERST 674 675DEF("m", HAS_ARG, QEMU_OPTION_m, 676 "-m [size=]megs[,slots=n,maxmem=size]\n" 677 " configure guest RAM\n" 678 " size: initial amount of guest memory\n" 679 " slots: number of hotplug slots (default: none)\n" 680 " maxmem: maximum amount of guest memory (default: none)\n" 681 " Note: Some architectures might enforce a specific granularity\n", 682 QEMU_ARCH_ALL) 683SRST 684``-m [size=]megs[,slots=n,maxmem=size]`` 685 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 686 Optionally, a suffix of "M" or "G" can be used to signify a value in 687 megabytes or gigabytes respectively. Optional pair slots, maxmem 688 could be used to set amount of hotpluggable memory slots and maximum 689 amount of memory. Note that maxmem must be aligned to the page size. 690 691 For example, the following command-line sets the guest startup RAM 692 size to 1GB, creates 3 slots to hotplug additional memory and sets 693 the maximum memory the guest can reach to 4GB: 694 695 .. parsed-literal:: 696 697 |qemu_system| -m 1G,slots=3,maxmem=4G 698 699 If slots and maxmem are not specified, memory hotplug won't be 700 enabled and the guest startup RAM will never increase. 701ERST 702 703DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 704 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 705SRST 706``-mem-path path`` 707 Allocate guest RAM from a temporarily created file in path. 708ERST 709 710DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 711 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 712 QEMU_ARCH_ALL) 713SRST 714``-mem-prealloc`` 715 Preallocate memory when using -mem-path. 716ERST 717 718DEF("k", HAS_ARG, QEMU_OPTION_k, 719 "-k language use keyboard layout (for example 'fr' for French)\n", 720 QEMU_ARCH_ALL) 721SRST 722``-k language`` 723 Use keyboard layout language (for example ``fr`` for French). This 724 option is only needed where it is not easy to get raw PC keycodes 725 (e.g. on Macs, with some X11 servers or with a VNC or curses 726 display). You don't normally need to use it on PC/Linux or 727 PC/Windows hosts. 728 729 The available layouts are: 730 731 :: 732 733 ar de-ch es fo fr-ca hu ja mk no pt-br sv 734 da en-gb et fr fr-ch is lt nl pl ru th 735 de en-us fi fr-be hr it lv nl-be pt sl tr 736 737 The default is ``en-us``. 738ERST 739 740 741DEF("audio", HAS_ARG, QEMU_OPTION_audio, 742 "-audio [driver=]driver[,prop[=value][,...]]\n" 743 " specifies default audio backend when `audiodev` is not\n" 744 " used to create a machine or sound device;" 745 " options are the same as for -audiodev\n" 746 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 747 " specifies the audio backend and device to use;\n" 748 " apart from 'model', options are the same as for -audiodev.\n" 749 " use '-audio model=help' to show possible devices.\n", 750 QEMU_ARCH_ALL) 751SRST 752``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 753 If the ``model`` option is specified, ``-audio`` is a shortcut 754 for configuring both the guest audio hardware and the host audio 755 backend in one go. The guest hardware model can be set with 756 ``model=modelname``. Use ``model=help`` to list the available 757 device types. 758 759 The following two example do exactly the same, to show how ``-audio`` 760 can be used to shorten the command line length: 761 762 .. parsed-literal:: 763 764 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 765 |qemu_system| -audio pa,model=sb16 766 767 If the ``model`` option is not specified, ``-audio`` is used to 768 configure a default audio backend that will be used whenever the 769 ``audiodev`` property is not set on a device or machine. In 770 particular, ``-audio none`` ensures that no audio is produced even 771 for machines that have embedded sound hardware. 772 773 In both cases, the driver option is the same as with the corresponding 774 ``-audiodev`` option below. Use ``driver=help`` to list the available 775 drivers. 776 777ERST 778 779DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 780 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 781 " specifies the audio backend to use\n" 782 " Use ``-audiodev help`` to list the available drivers\n" 783 " id= identifier of the backend\n" 784 " timer-period= timer period in microseconds\n" 785 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 786 " in|out.fixed-settings= use fixed settings for host audio\n" 787 " in|out.frequency= frequency to use with fixed settings\n" 788 " in|out.channels= number of channels to use with fixed settings\n" 789 " in|out.format= sample format to use with fixed settings\n" 790 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 791 " in|out.voices= number of voices to use\n" 792 " in|out.buffer-length= length of buffer in microseconds\n" 793 "-audiodev none,id=id,[,prop[=value][,...]]\n" 794 " dummy driver that discards all output\n" 795#ifdef CONFIG_AUDIO_ALSA 796 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 797 " in|out.dev= name of the audio device to use\n" 798 " in|out.period-length= length of period in microseconds\n" 799 " in|out.try-poll= attempt to use poll mode\n" 800 " threshold= threshold (in microseconds) when playback starts\n" 801#endif 802#ifdef CONFIG_AUDIO_COREAUDIO 803 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 804 " in|out.buffer-count= number of buffers\n" 805#endif 806#ifdef CONFIG_AUDIO_DSOUND 807 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 808 " latency= add extra latency to playback in microseconds\n" 809#endif 810#ifdef CONFIG_AUDIO_OSS 811 "-audiodev oss,id=id[,prop[=value][,...]]\n" 812 " in|out.dev= path of the audio device to use\n" 813 " in|out.buffer-count= number of buffers\n" 814 " in|out.try-poll= attempt to use poll mode\n" 815 " try-mmap= try using memory mapped access\n" 816 " exclusive= open device in exclusive mode\n" 817 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 818#endif 819#ifdef CONFIG_AUDIO_PA 820 "-audiodev pa,id=id[,prop[=value][,...]]\n" 821 " server= PulseAudio server address\n" 822 " in|out.name= source/sink device name\n" 823 " in|out.latency= desired latency in microseconds\n" 824#endif 825#ifdef CONFIG_AUDIO_PIPEWIRE 826 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 827 " in|out.name= source/sink device name\n" 828 " in|out.stream-name= name of pipewire stream\n" 829 " in|out.latency= desired latency in microseconds\n" 830#endif 831#ifdef CONFIG_AUDIO_SDL 832 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 833 " in|out.buffer-count= number of buffers\n" 834#endif 835#ifdef CONFIG_AUDIO_SNDIO 836 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 837#endif 838#ifdef CONFIG_SPICE 839 "-audiodev spice,id=id[,prop[=value][,...]]\n" 840#endif 841#ifdef CONFIG_DBUS_DISPLAY 842 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 843#endif 844 "-audiodev wav,id=id[,prop[=value][,...]]\n" 845 " path= path of wav file to record\n", 846 QEMU_ARCH_ALL) 847SRST 848``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 849 Adds a new audio backend driver identified by id. There are global 850 and driver specific properties. Some values can be set differently 851 for input and output, they're marked with ``in|out.``. You can set 852 the input's property with ``in.prop`` and the output's property with 853 ``out.prop``. For example: 854 855 :: 856 857 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 858 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 859 860 NOTE: parameter validation is known to be incomplete, in many cases 861 specifying an invalid option causes QEMU to print an error message 862 and continue emulation without sound. 863 864 Valid global options are: 865 866 ``id=identifier`` 867 Identifies the audio backend. 868 869 ``timer-period=period`` 870 Sets the timer period used by the audio subsystem in 871 microseconds. Default is 10000 (10 ms). 872 873 ``in|out.mixing-engine=on|off`` 874 Use QEMU's mixing engine to mix all streams inside QEMU and 875 convert audio formats when not supported by the backend. When 876 off, fixed-settings must be off too. Note that disabling this 877 option means that the selected backend must support multiple 878 streams and the audio formats used by the virtual cards, 879 otherwise you'll get no sound. It's not recommended to disable 880 this option unless you want to use 5.1 or 7.1 audio, as mixing 881 engine only supports mono and stereo audio. Default is on. 882 883 ``in|out.fixed-settings=on|off`` 884 Use fixed settings for host audio. When off, it will change 885 based on how the guest opens the sound card. In this case you 886 must not specify frequency, channels or format. Default is on. 887 888 ``in|out.frequency=frequency`` 889 Specify the frequency to use when using fixed-settings. Default 890 is 44100Hz. 891 892 ``in|out.channels=channels`` 893 Specify the number of channels to use when using fixed-settings. 894 Default is 2 (stereo). 895 896 ``in|out.format=format`` 897 Specify the sample format to use when using fixed-settings. 898 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 899 ``u32``, ``f32``. Default is ``s16``. 900 901 ``in|out.voices=voices`` 902 Specify the number of voices to use. Default is 1. 903 904 ``in|out.buffer-length=usecs`` 905 Sets the size of the buffer in microseconds. 906 907``-audiodev none,id=id[,prop[=value][,...]]`` 908 Creates a dummy backend that discards all outputs. This backend has 909 no backend specific properties. 910 911``-audiodev alsa,id=id[,prop[=value][,...]]`` 912 Creates backend using the ALSA. This backend is only available on 913 Linux. 914 915 ALSA specific options are: 916 917 ``in|out.dev=device`` 918 Specify the ALSA device to use for input and/or output. Default 919 is ``default``. 920 921 ``in|out.period-length=usecs`` 922 Sets the period length in microseconds. 923 924 ``in|out.try-poll=on|off`` 925 Attempt to use poll mode with the device. Default is on. 926 927 ``threshold=threshold`` 928 Threshold (in microseconds) when playback starts. Default is 0. 929 930``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 931 Creates a backend using Apple's Core Audio. This backend is only 932 available on Mac OS and only supports playback. 933 934 Core Audio specific options are: 935 936 ``in|out.buffer-count=count`` 937 Sets the count of the buffers. 938 939``-audiodev dsound,id=id[,prop[=value][,...]]`` 940 Creates a backend using Microsoft's DirectSound. This backend is 941 only available on Windows and only supports playback. 942 943 DirectSound specific options are: 944 945 ``latency=usecs`` 946 Add extra usecs microseconds latency to playback. Default is 947 10000 (10 ms). 948 949``-audiodev oss,id=id[,prop[=value][,...]]`` 950 Creates a backend using OSS. This backend is available on most 951 Unix-like systems. 952 953 OSS specific options are: 954 955 ``in|out.dev=device`` 956 Specify the file name of the OSS device to use. Default is 957 ``/dev/dsp``. 958 959 ``in|out.buffer-count=count`` 960 Sets the count of the buffers. 961 962 ``in|out.try-poll=on|of`` 963 Attempt to use poll mode with the device. Default is on. 964 965 ``try-mmap=on|off`` 966 Try using memory mapped device access. Default is off. 967 968 ``exclusive=on|off`` 969 Open the device in exclusive mode (vmix won't work in this 970 case). Default is off. 971 972 ``dsp-policy=policy`` 973 Sets the timing policy (between 0 and 10, where smaller number 974 means smaller latency but higher CPU usage). Use -1 to use 975 buffer sizes specified by ``buffer`` and ``buffer-count``. This 976 option is ignored if you do not have OSS 4. Default is 5. 977 978``-audiodev pa,id=id[,prop[=value][,...]]`` 979 Creates a backend using PulseAudio. This backend is available on 980 most systems. 981 982 PulseAudio specific options are: 983 984 ``server=server`` 985 Sets the PulseAudio server to connect to. 986 987 ``in|out.name=sink`` 988 Use the specified source/sink for recording/playback. 989 990 ``in|out.latency=usecs`` 991 Desired latency in microseconds. The PulseAudio server will try 992 to honor this value but actual latencies may be lower or higher. 993 994``-audiodev pipewire,id=id[,prop[=value][,...]]`` 995 Creates a backend using PipeWire. This backend is available on 996 most systems. 997 998 PipeWire specific options are: 999 1000 ``in|out.latency=usecs`` 1001 Desired latency in microseconds. 1002 1003 ``in|out.name=sink`` 1004 Use the specified source/sink for recording/playback. 1005 1006 ``in|out.stream-name`` 1007 Specify the name of pipewire stream. 1008 1009``-audiodev sdl,id=id[,prop[=value][,...]]`` 1010 Creates a backend using SDL. This backend is available on most 1011 systems, but you should use your platform's native backend if 1012 possible. 1013 1014 SDL specific options are: 1015 1016 ``in|out.buffer-count=count`` 1017 Sets the count of the buffers. 1018 1019``-audiodev sndio,id=id[,prop[=value][,...]]`` 1020 Creates a backend using SNDIO. This backend is available on 1021 OpenBSD and most other Unix-like systems. 1022 1023 Sndio specific options are: 1024 1025 ``in|out.dev=device`` 1026 Specify the sndio device to use for input and/or output. Default 1027 is ``default``. 1028 1029 ``in|out.latency=usecs`` 1030 Sets the desired period length in microseconds. 1031 1032``-audiodev spice,id=id[,prop[=value][,...]]`` 1033 Creates a backend that sends audio through SPICE. This backend 1034 requires ``-spice`` and automatically selected in that case, so 1035 usually you can ignore this option. This backend has no backend 1036 specific properties. 1037 1038``-audiodev wav,id=id[,prop[=value][,...]]`` 1039 Creates a backend that writes audio to a WAV file. 1040 1041 Backend specific options are: 1042 1043 ``path=path`` 1044 Write recorded audio into the specified file. Default is 1045 ``qemu.wav``. 1046ERST 1047 1048DEF("device", HAS_ARG, QEMU_OPTION_device, 1049 "-device driver[,prop[=value][,...]]\n" 1050 " add device (based on driver)\n" 1051 " prop=value,... sets driver properties\n" 1052 " use '-device help' to print all possible drivers\n" 1053 " use '-device driver,help' to print all possible properties\n", 1054 QEMU_ARCH_ALL) 1055SRST 1056``-device driver[,prop[=value][,...]]`` 1057 Add device driver. prop=value sets driver properties. Valid 1058 properties depend on the driver. To get help on possible drivers and 1059 properties, use ``-device help`` and ``-device driver,help``. 1060 1061 Some drivers are: 1062 1063``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1064 Add an IPMI BMC. This is a simulation of a hardware management 1065 interface processor that normally sits on a system. It provides a 1066 watchdog and the ability to reset and power control the system. You 1067 need to connect this to an IPMI interface to make it useful 1068 1069 The IPMI slave address to use for the BMC. The default is 0x20. This 1070 address is the BMC's address on the I2C network of management 1071 controllers. If you don't know what this means, it is safe to ignore 1072 it. 1073 1074 ``id=id`` 1075 The BMC id for interfaces to use this device. 1076 1077 ``slave_addr=val`` 1078 Define slave address to use for the BMC. The default is 0x20. 1079 1080 ``sdrfile=file`` 1081 file containing raw Sensor Data Records (SDR) data. The default 1082 is none. 1083 1084 ``fruareasize=val`` 1085 size of a Field Replaceable Unit (FRU) area. The default is 1086 1024. 1087 1088 ``frudatafile=file`` 1089 file containing raw Field Replaceable Unit (FRU) inventory data. 1090 The default is none. 1091 1092 ``guid=uuid`` 1093 value for the GUID for the BMC, in standard UUID format. If this 1094 is set, get "Get GUID" command to the BMC will return it. 1095 Otherwise "Get GUID" will return an error. 1096 1097``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1098 Add a connection to an external IPMI BMC simulator. Instead of 1099 locally emulating the BMC like the above item, instead connect to an 1100 external entity that provides the IPMI services. 1101 1102 A connection is made to an external BMC simulator. If you do this, 1103 it is strongly recommended that you use the "reconnect=" chardev 1104 option to reconnect to the simulator if the connection is lost. Note 1105 that if this is not used carefully, it can be a security issue, as 1106 the interface has the ability to send resets, NMIs, and power off 1107 the VM. It's best if QEMU makes a connection to an external 1108 simulator running on a secure port on localhost, so neither the 1109 simulator nor QEMU is exposed to any outside network. 1110 1111 See the "lanserv/README.vm" file in the OpenIPMI library for more 1112 details on the external interface. 1113 1114``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1115 Add a KCS IPMI interface on the ISA bus. This also adds a 1116 corresponding ACPI and SMBIOS entries, if appropriate. 1117 1118 ``bmc=id`` 1119 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1120 above. 1121 1122 ``ioport=val`` 1123 Define the I/O address of the interface. The default is 0xca0 1124 for KCS. 1125 1126 ``irq=val`` 1127 Define the interrupt to use. The default is 5. To disable 1128 interrupts, set this to 0. 1129 1130``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1131 Like the KCS interface, but defines a BT interface. The default port 1132 is 0xe4 and the default interrupt is 5. 1133 1134``-device pci-ipmi-kcs,bmc=id`` 1135 Add a KCS IPMI interface on the PCI bus. 1136 1137 ``bmc=id`` 1138 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1139 1140``-device pci-ipmi-bt,bmc=id`` 1141 Like the KCS interface, but defines a BT interface on the PCI bus. 1142 1143``-device intel-iommu[,option=...]`` 1144 This is only supported by ``-machine q35``, which will enable Intel VT-d 1145 emulation within the guest. It supports below options: 1146 1147 ``intremap=on|off`` (default: auto) 1148 This enables interrupt remapping feature. It's required to enable 1149 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1150 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1151 The default value is "auto", which will be decided by the mode of 1152 kernel-irqchip. 1153 1154 ``caching-mode=on|off`` (default: off) 1155 This enables caching mode for the VT-d emulated device. When 1156 caching-mode is enabled, each guest DMA buffer mapping will generate an 1157 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1158 a synchronous way. It is required for ``-device vfio-pci`` to work 1159 with the VT-d device, because host assigned devices requires to setup 1160 the DMA mapping on the host before guest DMA starts. 1161 1162 ``device-iotlb=on|off`` (default: off) 1163 This enables device-iotlb capability for the emulated VT-d device. So 1164 far virtio/vhost should be the only real user for this parameter, 1165 paired with ats=on configured for the device. 1166 1167 ``aw-bits=39|48`` (default: 39) 1168 This decides the address width of IOVA address space. The address 1169 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1170 4-level IOMMU page tables. 1171 1172 Please also refer to the wiki page for general scenarios of VT-d 1173 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1174 1175``-device virtio-iommu-pci[,option=...]`` 1176 This is only supported by ``-machine q35`` (x86_64) and ``-machine virt`` (ARM). 1177 It supports below options: 1178 1179 ``granule=val`` (possible values are 4k, 8k, 16k, 64k and host; default: host) 1180 This decides the default granule to be be exposed by the 1181 virtio-iommu. If host, the granule matches the host page size. 1182 1183ERST 1184 1185DEF("name", HAS_ARG, QEMU_OPTION_name, 1186 "-name string1[,process=string2][,debug-threads=on|off]\n" 1187 " set the name of the guest\n" 1188 " string1 sets the window title and string2 the process name\n" 1189 " When debug-threads is enabled, individual threads are given a separate name\n" 1190 " NOTE: The thread names are for debugging and not a stable API.\n", 1191 QEMU_ARCH_ALL) 1192SRST 1193``-name name`` 1194 Sets the name of the guest. This name will be displayed in the SDL 1195 window caption. The name will also be used for the VNC server. Also 1196 optionally set the top visible process name in Linux. Naming of 1197 individual threads can also be enabled on Linux to aid debugging. 1198ERST 1199 1200DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1201 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1202 " specify machine UUID\n", QEMU_ARCH_ALL) 1203SRST 1204``-uuid uuid`` 1205 Set system UUID. 1206ERST 1207 1208DEFHEADING() 1209 1210DEFHEADING(Block device options:) 1211 1212SRST 1213The QEMU block device handling options have a long history and 1214have gone through several iterations as the feature set and complexity 1215of the block layer have grown. Many online guides to QEMU often 1216reference older and deprecated options, which can lead to confusion. 1217 1218The most explicit way to describe disks is to use a combination of 1219``-device`` to specify the hardware device and ``-blockdev`` to 1220describe the backend. The device defines what the guest sees and the 1221backend describes how QEMU handles the data. It is the only guaranteed 1222stable interface for describing block devices and as such is 1223recommended for management tools and scripting. 1224 1225The ``-drive`` option combines the device and backend into a single 1226command line option which is a more human friendly. There is however no 1227interface stability guarantee although some older board models still 1228need updating to work with the modern blockdev forms. 1229 1230Older options like ``-hda`` are essentially macros which expand into 1231``-drive`` options for various drive interfaces. The original forms 1232bake in a lot of assumptions from the days when QEMU was emulating a 1233legacy PC, they are not recommended for modern configurations. 1234 1235ERST 1236 1237DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1238 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1239DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1240SRST 1241``-fda file`` 1242 \ 1243``-fdb file`` 1244 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1245 the System Emulation Users Guide). 1246ERST 1247 1248DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1249 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1250DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1251DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1252 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1253DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1254SRST 1255``-hda file`` 1256 \ 1257``-hdb file`` 1258 \ 1259``-hdc file`` 1260 \ 1261``-hdd file`` 1262 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1263 emulated machine (this is for example the IDE bus on most x86 machines, 1264 but it can also be SCSI, virtio or something else on other target 1265 architectures). See also the :ref:`disk images` chapter in the System 1266 Emulation Users Guide. 1267ERST 1268 1269DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1270 "-cdrom file use 'file' as CD-ROM image\n", 1271 QEMU_ARCH_ALL) 1272SRST 1273``-cdrom file`` 1274 Use file as CD-ROM image on the default bus of the emulated machine 1275 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1276 at the same time there). On systems that support it, you can use the 1277 host CD-ROM by using ``/dev/cdrom`` as filename. 1278ERST 1279 1280DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1281 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1282 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1283 " [,read-only=on|off][,auto-read-only=on|off]\n" 1284 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1285 " [,driver specific parameters...]\n" 1286 " configure a block backend\n", QEMU_ARCH_ALL) 1287SRST 1288``-blockdev option[,option[,option[,...]]]`` 1289 Define a new block driver node. Some of the options apply to all 1290 block drivers, other options are only accepted for a specific block 1291 driver. See below for a list of generic options and options for the 1292 most common block drivers. 1293 1294 Options that expect a reference to another node (e.g. ``file``) can 1295 be given in two ways. Either you specify the node name of an already 1296 existing node (file=node-name), or you define a new node inline, 1297 adding options for the referenced node after a dot 1298 (file.filename=path,file.aio=native). 1299 1300 A block driver node created with ``-blockdev`` can be used for a 1301 guest device by specifying its node name for the ``drive`` property 1302 in a ``-device`` argument that defines a block device. 1303 1304 ``Valid options for any block driver node:`` 1305 ``driver`` 1306 Specifies the block driver to use for the given node. 1307 1308 ``node-name`` 1309 This defines the name of the block driver node by which it 1310 will be referenced later. The name must be unique, i.e. it 1311 must not match the name of a different block driver node, or 1312 (if you use ``-drive`` as well) the ID of a drive. 1313 1314 If no node name is specified, it is automatically generated. 1315 The generated node name is not intended to be predictable 1316 and changes between QEMU invocations. For the top level, an 1317 explicit node name must be specified. 1318 1319 ``read-only`` 1320 Open the node read-only. Guest write attempts will fail. 1321 1322 Note that some block drivers support only read-only access, 1323 either generally or in certain configurations. In this case, 1324 the default value ``read-only=off`` does not work and the 1325 option must be specified explicitly. 1326 1327 ``auto-read-only`` 1328 If ``auto-read-only=on`` is set, QEMU may fall back to 1329 read-only usage even when ``read-only=off`` is requested, or 1330 even switch between modes as needed, e.g. depending on 1331 whether the image file is writable or whether a writing user 1332 is attached to the node. 1333 1334 ``force-share`` 1335 Override the image locking system of QEMU by forcing the 1336 node to utilize weaker shared access for permissions where 1337 it would normally request exclusive access. When there is 1338 the potential for multiple instances to have the same file 1339 open (whether this invocation of QEMU is the first or the 1340 second instance), both instances must permit shared access 1341 for the second instance to succeed at opening the file. 1342 1343 Enabling ``force-share=on`` requires ``read-only=on``. 1344 1345 ``cache.direct`` 1346 The host page cache can be avoided with ``cache.direct=on``. 1347 This will attempt to do disk IO directly to the guest's 1348 memory. QEMU may still perform an internal copy of the data. 1349 1350 ``cache.no-flush`` 1351 In case you don't care about data integrity over host 1352 failures, you can use ``cache.no-flush=on``. This option 1353 tells QEMU that it never needs to write any data to the disk 1354 but can instead keep things in cache. If anything goes 1355 wrong, like your host losing power, the disk storage getting 1356 disconnected accidentally, etc. your image will most 1357 probably be rendered unusable. 1358 1359 ``discard=discard`` 1360 discard is one of "ignore" (or "off") or "unmap" (or "on") 1361 and controls whether ``discard`` (also known as ``trim`` or 1362 ``unmap``) requests are ignored or passed to the filesystem. 1363 Some machine types may not support discard requests. 1364 1365 ``detect-zeroes=detect-zeroes`` 1366 detect-zeroes is "off", "on" or "unmap" and enables the 1367 automatic conversion of plain zero writes by the OS to 1368 driver specific optimized zero write commands. You may even 1369 choose "unmap" if discard is set to "unmap" to allow a zero 1370 write to be converted to an ``unmap`` operation. 1371 1372 ``Driver-specific options for file`` 1373 This is the protocol-level block driver for accessing regular 1374 files. 1375 1376 ``filename`` 1377 The path to the image file in the local filesystem 1378 1379 ``aio`` 1380 Specifies the AIO backend (threads/native/io_uring, 1381 default: threads) 1382 1383 ``locking`` 1384 Specifies whether the image file is protected with Linux OFD 1385 / POSIX locks. The default is to use the Linux Open File 1386 Descriptor API if available, otherwise no lock is applied. 1387 (auto/on/off, default: auto) 1388 1389 Example: 1390 1391 :: 1392 1393 -blockdev driver=file,node-name=disk,filename=disk.img 1394 1395 ``Driver-specific options for raw`` 1396 This is the image format block driver for raw images. It is 1397 usually stacked on top of a protocol level block driver such as 1398 ``file``. 1399 1400 ``file`` 1401 Reference to or definition of the data source block driver 1402 node (e.g. a ``file`` driver node) 1403 1404 Example 1: 1405 1406 :: 1407 1408 -blockdev driver=file,node-name=disk_file,filename=disk.img 1409 -blockdev driver=raw,node-name=disk,file=disk_file 1410 1411 Example 2: 1412 1413 :: 1414 1415 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1416 1417 ``Driver-specific options for qcow2`` 1418 This is the image format block driver for qcow2 images. It is 1419 usually stacked on top of a protocol level block driver such as 1420 ``file``. 1421 1422 ``file`` 1423 Reference to or definition of the data source block driver 1424 node (e.g. a ``file`` driver node) 1425 1426 ``backing`` 1427 Reference to or definition of the backing file block device 1428 (default is taken from the image file). It is allowed to 1429 pass ``null`` here in order to disable the default backing 1430 file. 1431 1432 ``lazy-refcounts`` 1433 Whether to enable the lazy refcounts feature (on/off; 1434 default is taken from the image file) 1435 1436 ``cache-size`` 1437 The maximum total size of the L2 table and refcount block 1438 caches in bytes (default: the sum of l2-cache-size and 1439 refcount-cache-size) 1440 1441 ``l2-cache-size`` 1442 The maximum size of the L2 table cache in bytes (default: if 1443 cache-size is not specified - 32M on Linux platforms, and 8M 1444 on non-Linux platforms; otherwise, as large as possible 1445 within the cache-size, while permitting the requested or the 1446 minimal refcount cache size) 1447 1448 ``refcount-cache-size`` 1449 The maximum size of the refcount block cache in bytes 1450 (default: 4 times the cluster size; or if cache-size is 1451 specified, the part of it which is not used for the L2 1452 cache) 1453 1454 ``cache-clean-interval`` 1455 Clean unused entries in the L2 and refcount caches. The 1456 interval is in seconds. The default value is 600 on 1457 supporting platforms, and 0 on other platforms. Setting it 1458 to 0 disables this feature. 1459 1460 ``pass-discard-request`` 1461 Whether discard requests to the qcow2 device should be 1462 forwarded to the data source (on/off; default: on if 1463 discard=unmap is specified, off otherwise) 1464 1465 ``pass-discard-snapshot`` 1466 Whether discard requests for the data source should be 1467 issued when a snapshot operation (e.g. deleting a snapshot) 1468 frees clusters in the qcow2 file (on/off; default: on) 1469 1470 ``pass-discard-other`` 1471 Whether discard requests for the data source should be 1472 issued on other occasions where a cluster gets freed 1473 (on/off; default: off) 1474 1475 ``discard-no-unref`` 1476 When enabled, data clusters will remain preallocated when they are 1477 no longer used, e.g. because they are discarded or converted to 1478 zero clusters. As usual, whether the old data is discarded or kept 1479 on the protocol level (i.e. in the image file) depends on the 1480 setting of the pass-discard-request option. Keeping the clusters 1481 preallocated prevents qcow2 fragmentation that would otherwise be 1482 caused by freeing and re-allocating them later. Besides potential 1483 performance degradation, such fragmentation can lead to increased 1484 allocation of clusters past the end of the image file, 1485 resulting in image files whose file length can grow much larger 1486 than their guest disk size would suggest. 1487 If image file length is of concern (e.g. when storing qcow2 1488 images directly on block devices), you should consider enabling 1489 this option. 1490 1491 ``overlap-check`` 1492 Which overlap checks to perform for writes to the image 1493 (none/constant/cached/all; default: cached). For details or 1494 finer granularity control refer to the QAPI documentation of 1495 ``blockdev-add``. 1496 1497 Example 1: 1498 1499 :: 1500 1501 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1502 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1503 1504 Example 2: 1505 1506 :: 1507 1508 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1509 1510 ``Driver-specific options for other drivers`` 1511 Please refer to the QAPI documentation of the ``blockdev-add`` 1512 QMP command. 1513ERST 1514 1515DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1516 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1517 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1518 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1519 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1520 " [,aio=threads|native|io_uring]\n" 1521 " [,readonly=on|off][,copy-on-read=on|off]\n" 1522 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1523 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1524 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1525 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1526 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1527 " [[,iops_size=is]]\n" 1528 " [[,group=g]]\n" 1529 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1530SRST 1531``-drive option[,option[,option[,...]]]`` 1532 Define a new drive. This includes creating a block driver node (the 1533 backend) as well as a guest device, and is mostly a shortcut for 1534 defining the corresponding ``-blockdev`` and ``-device`` options. 1535 1536 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1537 In addition, it knows the following options: 1538 1539 ``file=file`` 1540 This option defines which disk image (see the :ref:`disk images` 1541 chapter in the System Emulation Users Guide) to use with this drive. 1542 If the filename contains comma, you must double it (for instance, 1543 "file=my,,file" to use file "my,file"). 1544 1545 Special files such as iSCSI devices can be specified using 1546 protocol specific URLs. See the section for "Device URL Syntax" 1547 for more information. 1548 1549 ``if=interface`` 1550 This option defines on which type on interface the drive is 1551 connected. Available types are: ide, scsi, sd, mtd, floppy, 1552 pflash, virtio, none. 1553 1554 ``bus=bus,unit=unit`` 1555 These options define where is connected the drive by defining 1556 the bus number and the unit id. 1557 1558 ``index=index`` 1559 This option defines where the drive is connected by using an 1560 index in the list of available connectors of a given interface 1561 type. 1562 1563 ``media=media`` 1564 This option defines the type of the media: disk or cdrom. 1565 1566 ``snapshot=snapshot`` 1567 snapshot is "on" or "off" and controls snapshot mode for the 1568 given drive (see ``-snapshot``). 1569 1570 ``cache=cache`` 1571 cache is "none", "writeback", "unsafe", "directsync" or 1572 "writethrough" and controls how the host cache is used to access 1573 block data. This is a shortcut that sets the ``cache.direct`` 1574 and ``cache.no-flush`` options (as in ``-blockdev``), and 1575 additionally ``cache.writeback``, which provides a default for 1576 the ``write-cache`` option of block guest devices (as in 1577 ``-device``). The modes correspond to the following settings: 1578 1579 ============= =============== ============ ============== 1580 \ cache.writeback cache.direct cache.no-flush 1581 ============= =============== ============ ============== 1582 writeback on off off 1583 none on on off 1584 writethrough off off off 1585 directsync off on off 1586 unsafe on off on 1587 ============= =============== ============ ============== 1588 1589 The default mode is ``cache=writeback``. 1590 1591 ``aio=aio`` 1592 aio is "threads", "native", or "io_uring" and selects between pthread 1593 based disk I/O, native Linux AIO, or Linux io_uring API. 1594 1595 ``format=format`` 1596 Specify which disk format will be used rather than detecting the 1597 format. Can be used to specify format=raw to avoid interpreting 1598 an untrusted format header. 1599 1600 ``werror=action,rerror=action`` 1601 Specify which action to take on write and read errors. Valid 1602 actions are: "ignore" (ignore the error and try to continue), 1603 "stop" (pause QEMU), "report" (report the error to the guest), 1604 "enospc" (pause QEMU only if the host disk is full; report the 1605 error to the guest otherwise). The default setting is 1606 ``werror=enospc`` and ``rerror=report``. 1607 1608 ``copy-on-read=copy-on-read`` 1609 copy-on-read is "on" or "off" and enables whether to copy read 1610 backing file sectors into the image file. 1611 1612 ``bps=b,bps_rd=r,bps_wr=w`` 1613 Specify bandwidth throttling limits in bytes per second, either 1614 for all request types or for reads or writes only. Small values 1615 can lead to timeouts or hangs inside the guest. A safe minimum 1616 for disks is 2 MB/s. 1617 1618 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1619 Specify bursts in bytes per second, either for all request types 1620 or for reads or writes only. Bursts allow the guest I/O to spike 1621 above the limit temporarily. 1622 1623 ``iops=i,iops_rd=r,iops_wr=w`` 1624 Specify request rate limits in requests per second, either for 1625 all request types or for reads or writes only. 1626 1627 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1628 Specify bursts in requests per second, either for all request 1629 types or for reads or writes only. Bursts allow the guest I/O to 1630 spike above the limit temporarily. 1631 1632 ``iops_size=is`` 1633 Let every is bytes of a request count as a new request for iops 1634 throttling purposes. Use this option to prevent guests from 1635 circumventing iops limits by sending fewer but larger requests. 1636 1637 ``group=g`` 1638 Join a throttling quota group with given name g. All drives that 1639 are members of the same group are accounted for together. Use 1640 this option to prevent guests from circumventing throttling 1641 limits by using many small disks instead of a single larger 1642 disk. 1643 1644 By default, the ``cache.writeback=on`` mode is used. It will report 1645 data writes as completed as soon as the data is present in the host 1646 page cache. This is safe as long as your guest OS makes sure to 1647 correctly flush disk caches where needed. If your guest OS does not 1648 handle volatile disk write caches correctly and your host crashes or 1649 loses power, then the guest may experience data corruption. 1650 1651 For such guests, you should consider using ``cache.writeback=off``. 1652 This means that the host page cache will be used to read and write 1653 data, but write notification will be sent to the guest only after 1654 QEMU has made sure to flush each write to the disk. Be aware that 1655 this has a major impact on performance. 1656 1657 When using the ``-snapshot`` option, unsafe caching is always used. 1658 1659 Copy-on-read avoids accessing the same backing file sectors 1660 repeatedly and is useful when the backing file is over a slow 1661 network. By default copy-on-read is off. 1662 1663 Instead of ``-cdrom`` you can use: 1664 1665 .. parsed-literal:: 1666 1667 |qemu_system| -drive file=file,index=2,media=cdrom 1668 1669 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1670 1671 .. parsed-literal:: 1672 1673 |qemu_system| -drive file=file,index=0,media=disk 1674 |qemu_system| -drive file=file,index=1,media=disk 1675 |qemu_system| -drive file=file,index=2,media=disk 1676 |qemu_system| -drive file=file,index=3,media=disk 1677 1678 You can open an image using pre-opened file descriptors from an fd 1679 set: 1680 1681 .. parsed-literal:: 1682 1683 |qemu_system| \\ 1684 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1685 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1686 -drive file=/dev/fdset/2,index=0,media=disk 1687 1688 You can connect a CDROM to the slave of ide0: 1689 1690 .. parsed-literal:: 1691 1692 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1693 1694 If you don't specify the "file=" argument, you define an empty 1695 drive: 1696 1697 .. parsed-literal:: 1698 1699 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1700 1701 Instead of ``-fda``, ``-fdb``, you can use: 1702 1703 .. parsed-literal:: 1704 1705 |qemu_system_x86| -drive file=file,index=0,if=floppy 1706 |qemu_system_x86| -drive file=file,index=1,if=floppy 1707 1708 By default, interface is "ide" and index is automatically 1709 incremented: 1710 1711 .. parsed-literal:: 1712 1713 |qemu_system_x86| -drive file=a -drive file=b 1714 1715 is interpreted like: 1716 1717 .. parsed-literal:: 1718 1719 |qemu_system_x86| -hda a -hdb b 1720ERST 1721 1722DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1723 "-mtdblock file use 'file' as on-board Flash memory image\n", 1724 QEMU_ARCH_ALL) 1725SRST 1726``-mtdblock file`` 1727 Use file as on-board Flash memory image. 1728ERST 1729 1730DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1731 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1732SRST 1733``-sd file`` 1734 Use file as SecureDigital card image. 1735ERST 1736 1737DEF("snapshot", 0, QEMU_OPTION_snapshot, 1738 "-snapshot write to temporary files instead of disk image files\n", 1739 QEMU_ARCH_ALL) 1740SRST 1741``-snapshot`` 1742 Write to temporary files instead of disk image files. In this case, 1743 the raw disk image you use is not written back. You can however 1744 force the write back by pressing C-a s (see the :ref:`disk images` 1745 chapter in the System Emulation Users Guide). 1746 1747 .. warning:: 1748 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1749 to manually create snapshot images to attach to your blockdev). 1750 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1751 can use the 'snapshot' property on your drive declarations 1752 instead of this global option. 1753 1754ERST 1755 1756DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1757 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1758 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1759 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1760 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1761 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1762 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1763 " [[,throttling.iops-size=is]]\n" 1764 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1765 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1766 "-fsdev synth,id=id\n", 1767 QEMU_ARCH_ALL) 1768 1769SRST 1770``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1771 \ 1772``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1773 \ 1774``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1775 \ 1776``-fsdev synth,id=id[,readonly=on]`` 1777 Define a new file system device. Valid options are: 1778 1779 ``local`` 1780 Accesses to the filesystem are done by QEMU. 1781 1782 ``proxy`` 1783 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1784 option is deprecated (since QEMU 8.1) and will be removed in a future 1785 version of QEMU. Use ``local`` instead. 1786 1787 ``synth`` 1788 Synthetic filesystem, only used by QTests. 1789 1790 ``id=id`` 1791 Specifies identifier for this device. 1792 1793 ``path=path`` 1794 Specifies the export path for the file system device. Files 1795 under this path will be available to the 9p client on the guest. 1796 1797 ``security_model=security_model`` 1798 Specifies the security model to be used for this export path. 1799 Supported security models are "passthrough", "mapped-xattr", 1800 "mapped-file" and "none". In "passthrough" security model, files 1801 are stored using the same credentials as they are created on the 1802 guest. This requires QEMU to run as root. In "mapped-xattr" 1803 security model, some of the file attributes like uid, gid, mode 1804 bits and link target are stored as file attributes. For 1805 "mapped-file" these attributes are stored in the hidden 1806 .virtfs\_metadata directory. Directories exported by this 1807 security model cannot interact with other unix tools. "none" 1808 security model is same as passthrough except the sever won't 1809 report failures if it fails to set file attributes like 1810 ownership. Security model is mandatory only for local fsdriver. 1811 Other fsdrivers (like proxy) don't take security model as a 1812 parameter. 1813 1814 ``writeout=writeout`` 1815 This is an optional argument. The only supported value is 1816 "immediate". This means that host page cache will be used to 1817 read and write data but write notification will be sent to the 1818 guest only when the data has been reported as written by the 1819 storage subsystem. 1820 1821 ``readonly=on`` 1822 Enables exporting 9p share as a readonly mount for guests. By 1823 default read-write access is given. 1824 1825 ``socket=socket`` 1826 Enables proxy filesystem driver to use passed socket file for 1827 communicating with virtfs-proxy-helper(1). 1828 1829 ``sock_fd=sock_fd`` 1830 Enables proxy filesystem driver to use passed socket descriptor 1831 for communicating with virtfs-proxy-helper(1). Usually a helper 1832 like libvirt will create socketpair and pass one of the fds as 1833 sock\_fd. 1834 1835 ``fmode=fmode`` 1836 Specifies the default mode for newly created files on the host. 1837 Works only with security models "mapped-xattr" and 1838 "mapped-file". 1839 1840 ``dmode=dmode`` 1841 Specifies the default mode for newly created directories on the 1842 host. Works only with security models "mapped-xattr" and 1843 "mapped-file". 1844 1845 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1846 Specify bandwidth throttling limits in bytes per second, either 1847 for all request types or for reads or writes only. 1848 1849 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1850 Specify bursts in bytes per second, either for all request types 1851 or for reads or writes only. Bursts allow the guest I/O to spike 1852 above the limit temporarily. 1853 1854 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1855 Specify request rate limits in requests per second, either for 1856 all request types or for reads or writes only. 1857 1858 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1859 Specify bursts in requests per second, either for all request 1860 types or for reads or writes only. Bursts allow the guest I/O to 1861 spike above the limit temporarily. 1862 1863 ``throttling.iops-size=is`` 1864 Let every is bytes of a request count as a new request for iops 1865 throttling purposes. 1866 1867 -fsdev option is used along with -device driver "virtio-9p-...". 1868 1869``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1870 Options for virtio-9p-... driver are: 1871 1872 ``type`` 1873 Specifies the variant to be used. Supported values are "pci", 1874 "ccw" or "device", depending on the machine type. 1875 1876 ``fsdev=id`` 1877 Specifies the id value specified along with -fsdev option. 1878 1879 ``mount_tag=mount_tag`` 1880 Specifies the tag name to be used by the guest to mount this 1881 export point. 1882ERST 1883 1884DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1885 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1886 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1887 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1888 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1889 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1890 QEMU_ARCH_ALL) 1891 1892SRST 1893``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1894 \ 1895``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1896 \ 1897``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1898 \ 1899``-virtfs synth,mount_tag=mount_tag`` 1900 Define a new virtual filesystem device and expose it to the guest using 1901 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1902 directory on host is made directly accessible by guest as a pass-through 1903 file system by using the 9P network protocol for communication between 1904 host and guests, if desired even accessible, shared by several guests 1905 simultaneously. 1906 1907 Note that ``-virtfs`` is actually just a convenience shortcut for its 1908 generalized form ``-fsdev -device virtio-9p-pci``. 1909 1910 The general form of pass-through file system options are: 1911 1912 ``local`` 1913 Accesses to the filesystem are done by QEMU. 1914 1915 ``proxy`` 1916 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1917 This option is deprecated (since QEMU 8.1) and will be removed in a 1918 future version of QEMU. Use ``local`` instead. 1919 1920 ``synth`` 1921 Synthetic filesystem, only used by QTests. 1922 1923 ``id=id`` 1924 Specifies identifier for the filesystem device 1925 1926 ``path=path`` 1927 Specifies the export path for the file system device. Files 1928 under this path will be available to the 9p client on the guest. 1929 1930 ``security_model=security_model`` 1931 Specifies the security model to be used for this export path. 1932 Supported security models are "passthrough", "mapped-xattr", 1933 "mapped-file" and "none". In "passthrough" security model, files 1934 are stored using the same credentials as they are created on the 1935 guest. This requires QEMU to run as root. In "mapped-xattr" 1936 security model, some of the file attributes like uid, gid, mode 1937 bits and link target are stored as file attributes. For 1938 "mapped-file" these attributes are stored in the hidden 1939 .virtfs\_metadata directory. Directories exported by this 1940 security model cannot interact with other unix tools. "none" 1941 security model is same as passthrough except the sever won't 1942 report failures if it fails to set file attributes like 1943 ownership. Security model is mandatory only for local fsdriver. 1944 Other fsdrivers (like proxy) don't take security model as a 1945 parameter. 1946 1947 ``writeout=writeout`` 1948 This is an optional argument. The only supported value is 1949 "immediate". This means that host page cache will be used to 1950 read and write data but write notification will be sent to the 1951 guest only when the data has been reported as written by the 1952 storage subsystem. 1953 1954 ``readonly=on`` 1955 Enables exporting 9p share as a readonly mount for guests. By 1956 default read-write access is given. 1957 1958 ``socket=socket`` 1959 Enables proxy filesystem driver to use passed socket file for 1960 communicating with virtfs-proxy-helper(1). Usually a helper like 1961 libvirt will create socketpair and pass one of the fds as 1962 sock\_fd. 1963 1964 ``sock_fd`` 1965 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1966 socket descriptor for interfacing with virtfs-proxy-helper(1). 1967 1968 ``fmode=fmode`` 1969 Specifies the default mode for newly created files on the host. 1970 Works only with security models "mapped-xattr" and 1971 "mapped-file". 1972 1973 ``dmode=dmode`` 1974 Specifies the default mode for newly created directories on the 1975 host. Works only with security models "mapped-xattr" and 1976 "mapped-file". 1977 1978 ``mount_tag=mount_tag`` 1979 Specifies the tag name to be used by the guest to mount this 1980 export point. 1981 1982 ``multidevs=multidevs`` 1983 Specifies how to deal with multiple devices being shared with a 1984 9p export. Supported behaviours are either "remap", "forbid" or 1985 "warn". The latter is the default behaviour on which virtfs 9p 1986 expects only one device to be shared with the same export, and 1987 if more than one device is shared and accessed via the same 9p 1988 export then only a warning message is logged (once) by qemu on 1989 host side. In order to avoid file ID collisions on guest you 1990 should either create a separate virtfs export for each device to 1991 be shared with guests (recommended way) or you might use "remap" 1992 instead which allows you to share multiple devices with only one 1993 export instead, which is achieved by remapping the original 1994 inode numbers from host to guest in a way that would prevent 1995 such collisions. Remapping inodes in such use cases is required 1996 because the original device IDs from host are never passed and 1997 exposed on guest. Instead all files of an export shared with 1998 virtfs always share the same device id on guest. So two files 1999 with identical inode numbers but from actually different devices 2000 on host would otherwise cause a file ID collision and hence 2001 potential misbehaviours on guest. "forbid" on the other hand 2002 assumes like "warn" that only one device is shared by the same 2003 export, however it will not only log a warning message but also 2004 deny access to additional devices on guest. Note though that 2005 "forbid" does currently not block all possible file access 2006 operations (e.g. readdir() would still return entries from other 2007 devices). 2008ERST 2009 2010DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 2011 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 2012 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 2013 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 2014 " [,timeout=timeout]\n" 2015 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2016 2017SRST 2018``-iscsi`` 2019 Configure iSCSI session parameters. 2020ERST 2021 2022DEFHEADING() 2023 2024DEFHEADING(USB convenience options:) 2025 2026DEF("usb", 0, QEMU_OPTION_usb, 2027 "-usb enable on-board USB host controller (if not enabled by default)\n", 2028 QEMU_ARCH_ALL) 2029SRST 2030``-usb`` 2031 Enable USB emulation on machine types with an on-board USB host 2032 controller (if not enabled by default). Note that on-board USB host 2033 controllers may not support USB 3.0. In this case 2034 ``-device qemu-xhci`` can be used instead on machines with PCI. 2035ERST 2036 2037DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2038 "-usbdevice name add the host or guest USB device 'name'\n", 2039 QEMU_ARCH_ALL) 2040SRST 2041``-usbdevice devname`` 2042 Add the USB device devname, and enable an on-board USB controller 2043 if possible and necessary (just like it can be done via 2044 ``-machine usb=on``). Note that this option is mainly intended for 2045 the user's convenience only. More fine-grained control can be 2046 achieved by selecting a USB host controller (if necessary) and the 2047 desired USB device via the ``-device`` option instead. For example, 2048 instead of using ``-usbdevice mouse`` it is possible to use 2049 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2050 to a USB 3.0 controller instead (at least on machines that support 2051 PCI and do not have an USB controller enabled by default yet). 2052 For more details, see the chapter about 2053 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2054 Possible devices for devname are: 2055 2056 ``braille`` 2057 Braille device. This will use BrlAPI to display the braille 2058 output on a real or fake device (i.e. it also creates a 2059 corresponding ``braille`` chardev automatically beside the 2060 ``usb-braille`` USB device). 2061 2062 ``keyboard`` 2063 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2064 2065 ``mouse`` 2066 Virtual Mouse. This will override the PS/2 mouse emulation when 2067 activated. 2068 2069 ``tablet`` 2070 Pointer device that uses absolute coordinates (like a 2071 touchscreen). This means QEMU is able to report the mouse 2072 position without having to grab the mouse. Also overrides the 2073 PS/2 mouse emulation when activated. 2074 2075 ``wacom-tablet`` 2076 Wacom PenPartner USB tablet. 2077 2078 2079ERST 2080 2081DEFHEADING() 2082 2083DEFHEADING(Display options:) 2084 2085DEF("display", HAS_ARG, QEMU_OPTION_display, 2086#if defined(CONFIG_SPICE) 2087 "-display spice-app[,gl=on|off]\n" 2088#endif 2089#if defined(CONFIG_SDL) 2090 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2091 " [,window-close=on|off]\n" 2092#endif 2093#if defined(CONFIG_GTK) 2094 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2095 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2096 " [,show-menubar=on|off][,zoom-to-fit=on|off]\n" 2097#endif 2098#if defined(CONFIG_VNC) 2099 "-display vnc=<display>[,<optargs>]\n" 2100#endif 2101#if defined(CONFIG_CURSES) 2102 "-display curses[,charset=<encoding>]\n" 2103#endif 2104#if defined(CONFIG_COCOA) 2105 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2106 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2107 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2108#endif 2109#if defined(CONFIG_OPENGL) 2110 "-display egl-headless[,rendernode=<file>]\n" 2111#endif 2112#if defined(CONFIG_DBUS_DISPLAY) 2113 "-display dbus[,addr=<dbusaddr>]\n" 2114 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2115#endif 2116 "-display none\n" 2117 " select display backend type\n" 2118 " The default display is equivalent to\n " 2119#if defined(CONFIG_GTK) 2120 "\"-display gtk\"\n" 2121#elif defined(CONFIG_SDL) 2122 "\"-display sdl\"\n" 2123#elif defined(CONFIG_COCOA) 2124 "\"-display cocoa\"\n" 2125#elif defined(CONFIG_VNC) 2126 "\"-vnc localhost:0,to=99,id=default\"\n" 2127#else 2128 "\"-display none\"\n" 2129#endif 2130 , QEMU_ARCH_ALL) 2131SRST 2132``-display type`` 2133 Select type of display to use. Use ``-display help`` to list the available 2134 display types. Valid values for type are 2135 2136 ``spice-app[,gl=on|off]`` 2137 Start QEMU as a Spice server and launch the default Spice client 2138 application. The Spice server will redirect the serial consoles 2139 and QEMU monitors. (Since 4.0) 2140 2141 ``dbus`` 2142 Export the display over D-Bus interfaces. (Since 7.0) 2143 2144 The connection is registered with the "org.qemu" name (and queued when 2145 already owned). 2146 2147 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2148 2149 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2150 2151 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2152 will share framebuffers with DMABUF file descriptors). 2153 2154 ``sdl`` 2155 Display video output via SDL (usually in a separate graphics 2156 window; see the SDL documentation for other possibilities). 2157 Valid parameters are: 2158 2159 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2160 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2161 either ``lshift-lctrl-lalt`` or ``rctrl``. 2162 2163 ``gl=on|off|core|es`` : Use OpenGL for displaying 2164 2165 ``show-cursor=on|off`` : Force showing the mouse cursor 2166 2167 ``window-close=on|off`` : Allow to quit qemu with window close button 2168 2169 ``gtk`` 2170 Display video output in a GTK window. This interface provides 2171 drop-down menus and other UI elements to configure and control 2172 the VM during runtime. Valid parameters are: 2173 2174 ``full-screen=on|off`` : Start in fullscreen mode 2175 2176 ``gl=on|off`` : Use OpenGL for displaying 2177 2178 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2179 2180 ``show-tabs=on|off`` : Display the tab bar for switching between the 2181 various graphical interfaces (e.g. VGA and 2182 virtual console character devices) by default. 2183 2184 ``show-cursor=on|off`` : Force showing the mouse cursor 2185 2186 ``window-close=on|off`` : Allow to quit qemu with window close button 2187 2188 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2189 2190 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2191 defaults to "off" 2192 2193 ``curses[,charset=<encoding>]`` 2194 Display video output via curses. For graphics device models 2195 which support a text mode, QEMU can display this output using a 2196 curses/ncurses interface. Nothing is displayed when the graphics 2197 device is in graphical mode or if the graphics device does not 2198 support a text mode. Generally only the VGA device models 2199 support text mode. The font charset used by the guest can be 2200 specified with the ``charset`` option, for example 2201 ``charset=CP850`` for IBM CP850 encoding. The default is 2202 ``CP437``. 2203 2204 ``cocoa`` 2205 Display video output in a Cocoa window. Mac only. This interface 2206 provides drop-down menus and other UI elements to configure and 2207 control the VM during runtime. Valid parameters are: 2208 2209 ``full-grab=on|off`` : Capture all key presses, including system combos. 2210 This requires accessibility permissions, since it 2211 performs a global grab on key events. 2212 (default: off) See 2213 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2214 2215 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2216 key codes match their position on non-Mac 2217 keyboards and you can use Meta/Super and Alt 2218 where you expect them. (default: off) 2219 2220 ``show-cursor=on|off`` : Force showing the mouse cursor 2221 2222 ``left-command-key=on|off`` : Disable forwarding left command key to host 2223 2224 ``full-screen=on|off`` : Start in fullscreen mode 2225 2226 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2227 defaults to "off" 2228 2229 ``egl-headless[,rendernode=<file>]`` 2230 Offload all OpenGL operations to a local DRI device. For any 2231 graphical display, this display needs to be paired with either 2232 VNC or SPICE displays. 2233 2234 ``vnc=<display>`` 2235 Start a VNC server on display <display> 2236 2237 ``none`` 2238 Do not display video output. The guest will still see an 2239 emulated graphics card, but its output will not be displayed to 2240 the QEMU user. This option differs from the -nographic option in 2241 that it only affects what is done with video output; -nographic 2242 also changes the destination of the serial and parallel port 2243 data. 2244ERST 2245 2246DEF("nographic", 0, QEMU_OPTION_nographic, 2247 "-nographic disable graphical output and redirect serial I/Os to console\n", 2248 QEMU_ARCH_ALL) 2249SRST 2250``-nographic`` 2251 Normally, if QEMU is compiled with graphical window support, it 2252 displays output such as guest graphics, guest console, and the QEMU 2253 monitor in a window. With this option, you can totally disable 2254 graphical output so that QEMU is a simple command line application. 2255 The emulated serial port is redirected on the console and muxed with 2256 the monitor (unless redirected elsewhere explicitly). Therefore, you 2257 can still use QEMU to debug a Linux kernel with a serial console. 2258 Use C-a h for help on switching between the console and monitor. 2259ERST 2260 2261#ifdef CONFIG_SPICE 2262DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2263 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2264 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2265 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2266 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2267 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2268 " [,tls-ciphers=<list>]\n" 2269 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2270 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2271 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2272 " [,password-secret=<secret-id>]\n" 2273 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2274 " [,jpeg-wan-compression=[auto|never|always]]\n" 2275 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2276 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2277 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2278 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2279 " [,gl=[on|off]][,rendernode=<file>]\n" 2280 " enable spice\n" 2281 " at least one of {port, tls-port} is mandatory\n", 2282 QEMU_ARCH_ALL) 2283#endif 2284SRST 2285``-spice option[,option[,...]]`` 2286 Enable the spice remote desktop protocol. Valid options are 2287 2288 ``port=<nr>`` 2289 Set the TCP port spice is listening on for plaintext channels. 2290 2291 ``addr=<addr>`` 2292 Set the IP address spice is listening on. Default is any 2293 address. 2294 2295 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2296 Force using the specified IP version. 2297 2298 ``password-secret=<secret-id>`` 2299 Set the ID of the ``secret`` object containing the password 2300 you need to authenticate. 2301 2302 ``sasl=on|off`` 2303 Require that the client use SASL to authenticate with the spice. 2304 The exact choice of authentication method used is controlled 2305 from the system / user's SASL configuration file for the 'qemu' 2306 service. This is typically found in /etc/sasl2/qemu.conf. If 2307 running QEMU as an unprivileged user, an environment variable 2308 SASL\_CONF\_PATH can be used to make it search alternate 2309 locations for the service config. While some SASL auth methods 2310 can also provide data encryption (eg GSSAPI), it is recommended 2311 that SASL always be combined with the 'tls' and 'x509' settings 2312 to enable use of SSL and server certificates. This ensures a 2313 data encryption preventing compromise of authentication 2314 credentials. 2315 2316 ``disable-ticketing=on|off`` 2317 Allow client connects without authentication. 2318 2319 ``disable-copy-paste=on|off`` 2320 Disable copy paste between the client and the guest. 2321 2322 ``disable-agent-file-xfer=on|off`` 2323 Disable spice-vdagent based file-xfer between the client and the 2324 guest. 2325 2326 ``tls-port=<nr>`` 2327 Set the TCP port spice is listening on for encrypted channels. 2328 2329 ``x509-dir=<dir>`` 2330 Set the x509 file directory. Expects same filenames as -vnc 2331 $display,x509=$dir 2332 2333 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2334 The x509 file names can also be configured individually. 2335 2336 ``tls-ciphers=<list>`` 2337 Specify which ciphers to use. 2338 2339 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2340 Force specific channel to be used with or without TLS 2341 encryption. The options can be specified multiple times to 2342 configure multiple channels. The special name "default" can be 2343 used to set the default mode. For channels which are not 2344 explicitly forced into one mode the spice client is allowed to 2345 pick tls/plaintext as he pleases. 2346 2347 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2348 Configure image compression (lossless). Default is auto\_glz. 2349 2350 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2351 Configure wan image compression (lossy for slow links). Default 2352 is auto. 2353 2354 ``streaming-video=[off|all|filter]`` 2355 Configure video stream detection. Default is off. 2356 2357 ``agent-mouse=[on|off]`` 2358 Enable/disable passing mouse events via vdagent. Default is on. 2359 2360 ``playback-compression=[on|off]`` 2361 Enable/disable audio stream compression (using celt 0.5.1). 2362 Default is on. 2363 2364 ``seamless-migration=[on|off]`` 2365 Enable/disable spice seamless migration. Default is off. 2366 2367 ``gl=[on|off]`` 2368 Enable/disable OpenGL context. Default is off. 2369 2370 ``rendernode=<file>`` 2371 DRM render node for OpenGL rendering. If not specified, it will 2372 pick the first available. (Since 2.9) 2373ERST 2374 2375DEF("portrait", 0, QEMU_OPTION_portrait, 2376 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2377 QEMU_ARCH_ALL) 2378SRST 2379``-portrait`` 2380 Rotate graphical output 90 deg left (only PXA LCD). 2381ERST 2382 2383DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2384 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2385 QEMU_ARCH_ALL) 2386SRST 2387``-rotate deg`` 2388 Rotate graphical output some deg left (only PXA LCD). 2389ERST 2390 2391DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2392 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2393 " select video card type\n", QEMU_ARCH_ALL) 2394SRST 2395``-vga type`` 2396 Select type of VGA card to emulate. Valid values for type are 2397 2398 ``cirrus`` 2399 Cirrus Logic GD5446 Video card. All Windows versions starting 2400 from Windows 95 should recognize and use this graphic card. For 2401 optimal performances, use 16 bit color depth in the guest and 2402 the host OS. (This card was the default before QEMU 2.2) 2403 2404 ``std`` 2405 Standard VGA card with Bochs VBE extensions. If your guest OS 2406 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2407 you want to use high resolution modes (>= 1280x1024x16) then you 2408 should use this option. (This card is the default since QEMU 2409 2.2) 2410 2411 ``vmware`` 2412 VMWare SVGA-II compatible adapter. Use it if you have 2413 sufficiently recent XFree86/XOrg server or Windows guest with a 2414 driver for this card. 2415 2416 ``qxl`` 2417 QXL paravirtual graphic card. It is VGA compatible (including 2418 VESA 2.0 VBE support). Works best with qxl guest drivers 2419 installed though. Recommended choice when using the spice 2420 protocol. 2421 2422 ``tcx`` 2423 (sun4m only) Sun TCX framebuffer. This is the default 2424 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2425 colour depths at a fixed resolution of 1024x768. 2426 2427 ``cg3`` 2428 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2429 framebuffer for sun4m machines available in both 1024x768 2430 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2431 wishing to run older Solaris versions. 2432 2433 ``virtio`` 2434 Virtio VGA card. 2435 2436 ``none`` 2437 Disable VGA card. 2438ERST 2439 2440DEF("full-screen", 0, QEMU_OPTION_full_screen, 2441 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2442SRST 2443``-full-screen`` 2444 Start in full screen. 2445ERST 2446 2447DEF("g", HAS_ARG, QEMU_OPTION_g , 2448 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2449 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2450SRST 2451``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2452 Set the initial graphical resolution and depth (PPC, SPARC only). 2453 2454 For PPC the default is 800x600x32. 2455 2456 For SPARC with the TCX graphics device, the default is 1024x768x8 2457 with the option of 1024x768x24. For cgthree, the default is 2458 1024x768x8 with the option of 1152x900x8 for people who wish to use 2459 OBP. 2460ERST 2461 2462#ifdef CONFIG_VNC 2463DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2464 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2465#endif 2466SRST 2467``-vnc display[,option[,option[,...]]]`` 2468 Normally, if QEMU is compiled with graphical window support, it 2469 displays output such as guest graphics, guest console, and the QEMU 2470 monitor in a window. With this option, you can have QEMU listen on 2471 VNC display display and redirect the VGA display over the VNC 2472 session. It is very useful to enable the usb tablet device when 2473 using this option (option ``-device usb-tablet``). When using the 2474 VNC display, you must use the ``-k`` parameter to set the keyboard 2475 layout if you are not using en-us. Valid syntax for the display is 2476 2477 ``to=L`` 2478 With this option, QEMU will try next available VNC displays, 2479 until the number L, if the originally defined "-vnc display" is 2480 not available, e.g. port 5900+display is already used by another 2481 application. By default, to=0. 2482 2483 ``host:d`` 2484 TCP connections will only be allowed from host on display d. By 2485 convention the TCP port is 5900+d. Optionally, host can be 2486 omitted in which case the server will accept connections from 2487 any host. 2488 2489 ``unix:path`` 2490 Connections will be allowed over UNIX domain sockets where path 2491 is the location of a unix socket to listen for connections on. 2492 2493 ``none`` 2494 VNC is initialized but not started. The monitor ``change`` 2495 command can be used to later start the VNC server. 2496 2497 Following the display value there may be one or more option flags 2498 separated by commas. Valid options are 2499 2500 ``reverse=on|off`` 2501 Connect to a listening VNC client via a "reverse" connection. 2502 The client is specified by the display. For reverse network 2503 connections (host:d,``reverse``), the d argument is a TCP port 2504 number, not a display number. 2505 2506 ``websocket=on|off`` 2507 Opens an additional TCP listening port dedicated to VNC 2508 Websocket connections. If a bare websocket option is given, the 2509 Websocket port is 5700+display. An alternative port can be 2510 specified with the syntax ``websocket``\ =port. 2511 2512 If host is specified connections will only be allowed from this 2513 host. It is possible to control the websocket listen address 2514 independently, using the syntax ``websocket``\ =host:port. 2515 2516 If no TLS credentials are provided, the websocket connection 2517 runs in unencrypted mode. If TLS credentials are provided, the 2518 websocket connection requires encrypted client connections. 2519 2520 ``password=on|off`` 2521 Require that password based authentication is used for client 2522 connections. 2523 2524 The password must be set separately using the ``set_password`` 2525 command in the :ref:`QEMU monitor`. The 2526 syntax to change your password is: 2527 ``set_password <protocol> <password>`` where <protocol> could be 2528 either "vnc" or "spice". 2529 2530 If you would like to change <protocol> password expiration, you 2531 should use ``expire_password <protocol> <expiration-time>`` 2532 where expiration time could be one of the following options: 2533 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2534 make password expire in 60 seconds, or 1335196800 to make 2535 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2536 this date and time). 2537 2538 You can also use keywords "now" or "never" for the expiration 2539 time to allow <protocol> password to expire immediately or never 2540 expire. 2541 2542 ``password-secret=<secret-id>`` 2543 Require that password based authentication is used for client 2544 connections, using the password provided by the ``secret`` 2545 object identified by ``secret-id``. 2546 2547 ``tls-creds=ID`` 2548 Provides the ID of a set of TLS credentials to use to secure the 2549 VNC server. They will apply to both the normal VNC server socket 2550 and the websocket socket (if enabled). Setting TLS credentials 2551 will cause the VNC server socket to enable the VeNCrypt auth 2552 mechanism. The credentials should have been previously created 2553 using the ``-object tls-creds`` argument. 2554 2555 ``tls-authz=ID`` 2556 Provides the ID of the QAuthZ authorization object against which 2557 the client's x509 distinguished name will validated. This object 2558 is only resolved at time of use, so can be deleted and recreated 2559 on the fly while the VNC server is active. If missing, it will 2560 default to denying access. 2561 2562 ``sasl=on|off`` 2563 Require that the client use SASL to authenticate with the VNC 2564 server. The exact choice of authentication method used is 2565 controlled from the system / user's SASL configuration file for 2566 the 'qemu' service. This is typically found in 2567 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2568 an environment variable SASL\_CONF\_PATH can be used to make it 2569 search alternate locations for the service config. While some 2570 SASL auth methods can also provide data encryption (eg GSSAPI), 2571 it is recommended that SASL always be combined with the 'tls' 2572 and 'x509' settings to enable use of SSL and server 2573 certificates. This ensures a data encryption preventing 2574 compromise of authentication credentials. See the 2575 :ref:`VNC security` section in the System Emulation Users Guide 2576 for details on using SASL authentication. 2577 2578 ``sasl-authz=ID`` 2579 Provides the ID of the QAuthZ authorization object against which 2580 the client's SASL username will validated. This object is only 2581 resolved at time of use, so can be deleted and recreated on the 2582 fly while the VNC server is active. If missing, it will default 2583 to denying access. 2584 2585 ``acl=on|off`` 2586 Legacy method for enabling authorization of clients against the 2587 x509 distinguished name and SASL username. It results in the 2588 creation of two ``authz-list`` objects with IDs of 2589 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2590 objects must be configured with the HMP ACL commands. 2591 2592 This option is deprecated and should no longer be used. The new 2593 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2594 2595 ``lossy=on|off`` 2596 Enable lossy compression methods (gradient, JPEG, ...). If this 2597 option is set, VNC client may receive lossy framebuffer updates 2598 depending on its encoding settings. Enabling this option can 2599 save a lot of bandwidth at the expense of quality. 2600 2601 ``non-adaptive=on|off`` 2602 Disable adaptive encodings. Adaptive encodings are enabled by 2603 default. An adaptive encoding will try to detect frequently 2604 updated screen regions, and send updates in these regions using 2605 a lossy encoding (like JPEG). This can be really helpful to save 2606 bandwidth when playing videos. Disabling adaptive encodings 2607 restores the original static behavior of encodings like Tight. 2608 2609 ``share=[allow-exclusive|force-shared|ignore]`` 2610 Set display sharing policy. 'allow-exclusive' allows clients to 2611 ask for exclusive access. As suggested by the rfb spec this is 2612 implemented by dropping other connections. Connecting multiple 2613 clients in parallel requires all clients asking for a shared 2614 session (vncviewer: -shared switch). This is the default. 2615 'force-shared' disables exclusive client access. Useful for 2616 shared desktop sessions, where you don't want someone forgetting 2617 specify -shared disconnect everybody else. 'ignore' completely 2618 ignores the shared flag and allows everybody connect 2619 unconditionally. Doesn't conform to the rfb spec but is 2620 traditional QEMU behavior. 2621 2622 ``key-delay-ms`` 2623 Set keyboard delay, for key down and key up events, in 2624 milliseconds. Default is 10. Keyboards are low-bandwidth 2625 devices, so this slowdown can help the device and guest to keep 2626 up and not lose events in case events are arriving in bulk. 2627 Possible causes for the latter are flaky network connections, or 2628 scripts for automated testing. 2629 2630 ``audiodev=audiodev`` 2631 Use the specified audiodev when the VNC client requests audio 2632 transmission. When not using an -audiodev argument, this option 2633 must be omitted, otherwise is must be present and specify a 2634 valid audiodev. 2635 2636 ``power-control=on|off`` 2637 Permit the remote client to issue shutdown, reboot or reset power 2638 control requests. 2639ERST 2640 2641ARCHHEADING(, QEMU_ARCH_I386) 2642 2643ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2644 2645DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2646 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2647 QEMU_ARCH_I386) 2648SRST 2649``-win2k-hack`` 2650 Use it when installing Windows 2000 to avoid a disk full bug. After 2651 Windows 2000 is installed, you no longer need this option (this 2652 option slows down the IDE transfers). Synonym of ``-global 2653 ide-device.win2k-install-hack=on``. 2654ERST 2655 2656DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2657 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2658 QEMU_ARCH_I386) 2659SRST 2660``-no-fd-bootchk`` 2661 Disable boot signature checking for floppy disks in BIOS. May be 2662 needed to boot from old floppy disks. Synonym of ``-m fd-bootchk=off``. 2663ERST 2664 2665DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2666 "-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" 2667 " ACPI table description\n", QEMU_ARCH_I386) 2668SRST 2669``-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n] [,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]`` 2670 Add ACPI table with specified header fields and context from 2671 specified files. For file=, take whole ACPI table from the specified 2672 files, including all ACPI headers (possible overridden by other 2673 options). For data=, only data portion of the table is used, all 2674 header information is specified in the command line. If a SLIC table 2675 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2676 fields will override the same in the RSDT and the FADT (a.k.a. 2677 FACP), in order to ensure the field matches required by the 2678 Microsoft SLIC spec and the ACPI spec. 2679ERST 2680 2681DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2682 "-smbios file=binary\n" 2683 " load SMBIOS entry from binary file\n" 2684 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2685 " [,uefi=on|off]\n" 2686 " specify SMBIOS type 0 fields\n" 2687 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2688 " [,uuid=uuid][,sku=str][,family=str]\n" 2689 " specify SMBIOS type 1 fields\n" 2690 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2691 " [,asset=str][,location=str]\n" 2692 " specify SMBIOS type 2 fields\n" 2693 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2694 " [,sku=str]\n" 2695 " specify SMBIOS type 3 fields\n" 2696 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2697 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2698 " [,processor-family=%d,processor-id=%d]\n" 2699 " specify SMBIOS type 4 fields\n" 2700 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2701 " specify SMBIOS type 8 fields\n" 2702 "-smbios type=11[,value=str][,path=filename]\n" 2703 " specify SMBIOS type 11 fields\n" 2704 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2705 " [,asset=str][,part=str][,speed=%d]\n" 2706 " specify SMBIOS type 17 fields\n" 2707 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2708 " specify SMBIOS type 41 fields\n", 2709 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH | QEMU_ARCH_RISCV) 2710SRST 2711``-smbios file=binary`` 2712 Load SMBIOS entry from binary file. 2713 2714``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2715 Specify SMBIOS type 0 fields 2716 2717``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2718 Specify SMBIOS type 1 fields 2719 2720``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2721 Specify SMBIOS type 2 fields 2722 2723``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2724 Specify SMBIOS type 3 fields 2725 2726``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-family=%d][,processor-id=%d]`` 2727 Specify SMBIOS type 4 fields 2728 2729``-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]`` 2730 Specify SMBIOS type 9 fields 2731 2732``-smbios type=11[,value=str][,path=filename]`` 2733 Specify SMBIOS type 11 fields 2734 2735 This argument can be repeated multiple times, and values are added in the order they are parsed. 2736 Applications intending to use OEM strings data are encouraged to use their application name as 2737 a prefix for the value string. This facilitates passing information for multiple applications 2738 concurrently. 2739 2740 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2741 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2742 2743 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2744 the SMBIOS table in the order in which they appear. 2745 2746 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2747 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2748 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2749 data set, for example, by specifying the serial ID of a block device. 2750 2751 An example passing three strings is 2752 2753 .. parsed-literal:: 2754 2755 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2756 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2757 path=/some/file/with/oemstringsdata.txt 2758 2759 In the guest OS this is visible with the ``dmidecode`` command 2760 2761 .. parsed-literal:: 2762 2763 $ dmidecode -t 11 2764 Handle 0x0E00, DMI type 11, 5 bytes 2765 OEM Strings 2766 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2767 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2768 String 3: myapp:some extra data 2769 2770 2771``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2772 Specify SMBIOS type 17 fields 2773 2774``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2775 Specify SMBIOS type 41 fields 2776 2777 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2778 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2779 position on the PCI bus. 2780 2781 Here is an example of use: 2782 2783 .. parsed-literal:: 2784 2785 -netdev user,id=internet \\ 2786 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2787 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2788 2789 In the guest OS, the device should then appear as ``eno1``: 2790 2791 ..parsed-literal:: 2792 2793 $ ip -brief l 2794 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2795 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2796 2797 Currently, the PCI device has to be attached to the root bus. 2798 2799ERST 2800 2801DEFHEADING() 2802 2803DEFHEADING(Network options:) 2804 2805DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2806#ifdef CONFIG_SLIRP 2807 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2808 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2809 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2810 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2811 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2812#ifndef _WIN32 2813 "[,smb=dir[,smbserver=addr]]\n" 2814#endif 2815 " configure a user mode network backend with ID 'str',\n" 2816 " its DHCP server and optional services\n" 2817#endif 2818#ifdef _WIN32 2819 "-netdev tap,id=str,ifname=name\n" 2820 " configure a host TAP network backend with ID 'str'\n" 2821#else 2822 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2823 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2824 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2825 " [,poll-us=n]\n" 2826 " configure a host TAP network backend with ID 'str'\n" 2827 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2828 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2829 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2830 " to deconfigure it\n" 2831 " use '[down]script=no' to disable script execution\n" 2832 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2833 " configure it\n" 2834 " use 'fd=h' to connect to an already opened TAP interface\n" 2835 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2836 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2837 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2838 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2839 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2840 " use vhost=on to enable experimental in kernel accelerator\n" 2841 " (only has effect for virtio guests which use MSIX)\n" 2842 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2843 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2844 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2845 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2846 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2847 " spent on busy polling for vhost net\n" 2848 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2849 " configure a host TAP network backend with ID 'str' that is\n" 2850 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2851 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2852#endif 2853#ifdef __linux__ 2854 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2855 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2856 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2857 " [,rxcookie=rxcookie][,offset=offset]\n" 2858 " configure a network backend with ID 'str' connected to\n" 2859 " an Ethernet over L2TPv3 pseudowire.\n" 2860 " Linux kernel 3.3+ as well as most routers can talk\n" 2861 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2862 " VM to a router and even VM to Host. It is a nearly-universal\n" 2863 " standard (RFC3931). Note - this implementation uses static\n" 2864 " pre-configured tunnels (same as the Linux kernel).\n" 2865 " use 'src=' to specify source address\n" 2866 " use 'dst=' to specify destination address\n" 2867 " use 'udp=on' to specify udp encapsulation\n" 2868 " use 'srcport=' to specify source udp port\n" 2869 " use 'dstport=' to specify destination udp port\n" 2870 " use 'ipv6=on' to force v6\n" 2871 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2872 " well as a weak security measure\n" 2873 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2874 " use 'txcookie=0x012345678' to specify a txcookie\n" 2875 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2876 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2877 " use 'pincounter=on' to work around broken counter handling in peer\n" 2878 " use 'offset=X' to add an extra offset between header and data\n" 2879#endif 2880 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2881 " configure a network backend to connect to another network\n" 2882 " using a socket connection\n" 2883 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2884 " configure a network backend to connect to a multicast maddr and port\n" 2885 " use 'localaddr=addr' to specify the host address to send packets from\n" 2886 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2887 " configure a network backend to connect to another network\n" 2888 " using an UDP tunnel\n" 2889 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n" 2890 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2891 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2892 " configure a network backend to connect to another network\n" 2893 " using a socket connection in stream mode.\n" 2894 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2895 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2896 " configure a network backend to connect to a multicast maddr and port\n" 2897 " use ``local.host=addr`` to specify the host address to send packets from\n" 2898 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2899 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2900 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2901 " configure a network backend to connect to another network\n" 2902 " using an UDP tunnel\n" 2903#ifdef CONFIG_VDE 2904 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2905 " configure a network backend to connect to port 'n' of a vde switch\n" 2906 " running on host and listening for incoming connections on 'socketpath'.\n" 2907 " Use group 'groupname' and mode 'octalmode' to change default\n" 2908 " ownership and permissions for communication port.\n" 2909#endif 2910#ifdef CONFIG_NETMAP 2911 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2912 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2913 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2914 " netmap device, defaults to '/dev/netmap')\n" 2915#endif 2916#ifdef CONFIG_AF_XDP 2917 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2918 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2919 " attach to the existing network interface 'name' with AF_XDP socket\n" 2920 " use 'mode=MODE' to specify an XDP program attach mode\n" 2921 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2922 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2923 " with inhibit=on,\n" 2924 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2925 " added to a socket map in XDP program. One socket per queue.\n" 2926 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2927 " use 'start-queue=m' to specify the first queue that should be used\n" 2928#endif 2929#ifdef CONFIG_POSIX 2930 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2931 " configure a vhost-user network, backed by a chardev 'dev'\n" 2932#endif 2933#ifdef __linux__ 2934 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2935 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2936 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2937 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2938#endif 2939#ifdef CONFIG_VMNET 2940 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2941 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2942 " configure a vmnet network backend in host mode with ID 'str',\n" 2943 " isolate this interface from others with 'isolated',\n" 2944 " configure the address range and choose a subnet mask,\n" 2945 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2946 " vmnet-host interfaces within this isolated network\n" 2947 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2948 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2949 " configure a vmnet network backend in shared mode with ID 'str',\n" 2950 " configure the address range and choose a subnet mask,\n" 2951 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2952 " isolate this interface from others with 'isolated'\n" 2953 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2954 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2955 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2956 " isolate this interface from others with 'isolated'\n" 2957#endif 2958 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2959 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2960DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2961 "-nic [tap|bridge|" 2962#ifdef CONFIG_SLIRP 2963 "user|" 2964#endif 2965#ifdef __linux__ 2966 "l2tpv3|" 2967#endif 2968#ifdef CONFIG_VDE 2969 "vde|" 2970#endif 2971#ifdef CONFIG_NETMAP 2972 "netmap|" 2973#endif 2974#ifdef CONFIG_AF_XDP 2975 "af-xdp|" 2976#endif 2977#ifdef CONFIG_POSIX 2978 "vhost-user|" 2979#endif 2980#ifdef CONFIG_VMNET 2981 "vmnet-host|vmnet-shared|vmnet-bridged|" 2982#endif 2983 "socket][,option][,...][mac=macaddr]\n" 2984 " initialize an on-board / default host NIC (using MAC address\n" 2985 " macaddr) and connect it to the given host network backend\n" 2986 "-nic none use it alone to have zero network devices (the default is to\n" 2987 " provided a 'user' network connection)\n", 2988 QEMU_ARCH_ALL) 2989DEF("net", HAS_ARG, QEMU_OPTION_net, 2990 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2991 " configure or create an on-board (or machine default) NIC and\n" 2992 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2993 "-net [" 2994#ifdef CONFIG_SLIRP 2995 "user|" 2996#endif 2997 "tap|" 2998 "bridge|" 2999#ifdef CONFIG_VDE 3000 "vde|" 3001#endif 3002#ifdef CONFIG_NETMAP 3003 "netmap|" 3004#endif 3005#ifdef CONFIG_AF_XDP 3006 "af-xdp|" 3007#endif 3008#ifdef CONFIG_VMNET 3009 "vmnet-host|vmnet-shared|vmnet-bridged|" 3010#endif 3011 "socket][,option][,option][,...]\n" 3012 " old way to initialize a host network interface\n" 3013 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3014SRST 3015``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3016 This option is a shortcut for configuring both the on-board 3017 (default) guest NIC hardware and the host network backend in one go. 3018 The host backend options are the same as with the corresponding 3019 ``-netdev`` options below. The guest NIC model can be set with 3020 ``model=modelname``. Use ``model=help`` to list the available device 3021 types. The hardware MAC address can be set with ``mac=macaddr``. 3022 3023 The following two example do exactly the same, to show how ``-nic`` 3024 can be used to shorten the command line length: 3025 3026 .. parsed-literal:: 3027 3028 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3029 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3030 3031``-nic none`` 3032 Indicate that no network devices should be configured. It is used to 3033 override the default configuration (default NIC with "user" host 3034 network backend) which is activated if no other networking options 3035 are provided. 3036 3037``-netdev user,id=id[,option][,option][,...]`` 3038 Configure user mode host network backend which requires no 3039 administrator privilege to run. Valid options are: 3040 3041 ``id=id`` 3042 Assign symbolic name for use in monitor commands. 3043 3044 ``ipv4=on|off and ipv6=on|off`` 3045 Specify that either IPv4 or IPv6 must be enabled. If neither is 3046 specified both protocols are enabled. 3047 3048 ``net=addr[/mask]`` 3049 Set IP network address the guest will see. Optionally specify 3050 the netmask, either in the form a.b.c.d or as number of valid 3051 top-most bits. Default is 10.0.2.0/24. 3052 3053 ``host=addr`` 3054 Specify the guest-visible address of the host. Default is the 3055 2nd IP in the guest network, i.e. x.x.x.2. 3056 3057 ``ipv6-net=addr[/int]`` 3058 Set IPv6 network address the guest will see (default is 3059 fec0::/64). The network prefix is given in the usual hexadecimal 3060 IPv6 address notation. The prefix size is optional, and is given 3061 as the number of valid top-most bits (default is 64). 3062 3063 ``ipv6-host=addr`` 3064 Specify the guest-visible IPv6 address of the host. Default is 3065 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3066 3067 ``restrict=on|off`` 3068 If this option is enabled, the guest will be isolated, i.e. it 3069 will not be able to contact the host and no guest IP packets 3070 will be routed over the host to the outside. This option does 3071 not affect any explicitly set forwarding rules. 3072 3073 ``hostname=name`` 3074 Specifies the client hostname reported by the built-in DHCP 3075 server. 3076 3077 ``dhcpstart=addr`` 3078 Specify the first of the 16 IPs the built-in DHCP server can 3079 assign. Default is the 15th to 31st IP in the guest network, 3080 i.e. x.x.x.15 to x.x.x.31. 3081 3082 ``dns=addr`` 3083 Specify the guest-visible address of the virtual nameserver. The 3084 address must be different from the host address. Default is the 3085 3rd IP in the guest network, i.e. x.x.x.3. 3086 3087 ``ipv6-dns=addr`` 3088 Specify the guest-visible address of the IPv6 virtual 3089 nameserver. The address must be different from the host address. 3090 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3091 3092 ``dnssearch=domain`` 3093 Provides an entry for the domain-search list sent by the 3094 built-in DHCP server. More than one domain suffix can be 3095 transmitted by specifying this option multiple times. If 3096 supported, this will cause the guest to automatically try to 3097 append the given domain suffix(es) in case a domain name can not 3098 be resolved. 3099 3100 Example: 3101 3102 .. parsed-literal:: 3103 3104 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3105 3106 ``domainname=domain`` 3107 Specifies the client domain name reported by the built-in DHCP 3108 server. 3109 3110 ``tftp=dir`` 3111 When using the user mode network stack, activate a built-in TFTP 3112 server. The files in dir will be exposed as the root of a TFTP 3113 server. The TFTP client on the guest must be configured in 3114 binary mode (use the command ``bin`` of the Unix TFTP client). 3115 The built-in TFTP server is read-only; it does not implement any 3116 command for writing files. QEMU will not write to this directory. 3117 3118 ``tftp-server-name=name`` 3119 In BOOTP reply, broadcast name as the "TFTP server name" 3120 (RFC2132 option 66). This can be used to advise the guest to 3121 load boot files or configurations from a different server than 3122 the host address. 3123 3124 ``bootfile=file`` 3125 When using the user mode network stack, broadcast file as the 3126 BOOTP filename. In conjunction with ``tftp``, this can be used 3127 to network boot a guest from a local directory. 3128 3129 Example (using pxelinux): 3130 3131 .. parsed-literal:: 3132 3133 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3134 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3135 3136 ``smb=dir[,smbserver=addr]`` 3137 When using the user mode network stack, activate a built-in SMB 3138 server so that Windows OSes can access to the host files in 3139 ``dir`` transparently. The IP address of the SMB server can be 3140 set to addr. By default the 4th IP in the guest network is used, 3141 i.e. x.x.x.4. 3142 3143 In the guest Windows OS, the line: 3144 3145 :: 3146 3147 10.0.2.4 smbserver 3148 3149 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3150 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3151 NT/2000). 3152 3153 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3154 3155 Note that a SAMBA server must be installed on the host OS. 3156 3157 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3158 Redirect incoming TCP or UDP connections to the host port 3159 hostport to the guest IP address guestaddr on guest port 3160 guestport. If guestaddr is not specified, its value is x.x.x.15 3161 (default first address given by the built-in DHCP server). By 3162 specifying hostaddr, the rule can be bound to a specific host 3163 interface. If no connection type is set, TCP is used. This 3164 option can be given multiple times. 3165 3166 For example, to redirect host X11 connection from screen 1 to 3167 guest screen 0, use the following: 3168 3169 .. parsed-literal:: 3170 3171 # on the host 3172 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3173 # this host xterm should open in the guest X11 server 3174 xterm -display :1 3175 3176 To redirect telnet connections from host port 5555 to telnet 3177 port on the guest, use the following: 3178 3179 .. parsed-literal:: 3180 3181 # on the host 3182 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3183 telnet localhost 5555 3184 3185 Then when you use on the host ``telnet localhost 5555``, you 3186 connect to the guest telnet server. 3187 3188 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3189 Forward guest TCP connections to the IP address server on port 3190 port to the character device dev or to a program executed by 3191 cmd:command which gets spawned for each connection. This option 3192 can be given multiple times. 3193 3194 You can either use a chardev directly and have that one used 3195 throughout QEMU's lifetime, like in the following example: 3196 3197 .. parsed-literal:: 3198 3199 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3200 # the guest accesses it 3201 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3202 3203 Or you can execute a command on every TCP connection established 3204 by the guest, so that QEMU behaves similar to an inetd process 3205 for that virtual server: 3206 3207 .. parsed-literal:: 3208 3209 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3210 # and connect the TCP stream to its stdin/stdout 3211 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3212 3213``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3214 Configure a host TAP network backend with ID id. 3215 3216 Use the network script file to configure it and the network script 3217 dfile to deconfigure it. If name is not provided, the OS 3218 automatically provides one. The default network configure script is 3219 ``/etc/qemu-ifup`` and the default network deconfigure script is 3220 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3221 disable script execution. 3222 3223 If running QEMU as an unprivileged user, use the network helper 3224 to configure the TAP interface and attach it to the bridge. 3225 The default network helper executable is 3226 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3227 ``br0``. 3228 3229 ``fd``\ =h can be used to specify the handle of an already opened 3230 host TAP interface. 3231 3232 Examples: 3233 3234 .. parsed-literal:: 3235 3236 #launch a QEMU instance with the default network script 3237 |qemu_system| linux.img -nic tap 3238 3239 .. parsed-literal:: 3240 3241 #launch a QEMU instance with two NICs, each one connected 3242 #to a TAP device 3243 |qemu_system| linux.img \\ 3244 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3245 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3246 3247 .. parsed-literal:: 3248 3249 #launch a QEMU instance with the default network helper to 3250 #connect a TAP device to bridge br0 3251 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3252 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3253 3254``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3255 Connect a host TAP network interface to a host bridge device. 3256 3257 Use the network helper helper to configure the TAP interface and 3258 attach it to the bridge. The default network helper executable is 3259 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3260 ``br0``. 3261 3262 Examples: 3263 3264 .. parsed-literal:: 3265 3266 #launch a QEMU instance with the default network helper to 3267 #connect a TAP device to bridge br0 3268 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3269 3270 .. parsed-literal:: 3271 3272 #launch a QEMU instance with the default network helper to 3273 #connect a TAP device to bridge qemubr0 3274 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3275 3276``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3277 This host network backend can be used to connect the guest's network 3278 to another QEMU virtual machine using a TCP socket connection. If 3279 ``listen`` is specified, QEMU waits for incoming connections on port 3280 (host is optional). ``connect`` is used to connect to another QEMU 3281 instance using the ``listen`` option. ``fd``\ =h specifies an 3282 already opened TCP socket. 3283 3284 Example: 3285 3286 .. parsed-literal:: 3287 3288 # launch a first QEMU instance 3289 |qemu_system| linux.img \\ 3290 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3291 -netdev socket,id=n1,listen=:1234 3292 # connect the network of this instance to the network of the first instance 3293 |qemu_system| linux.img \\ 3294 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3295 -netdev socket,id=n2,connect=127.0.0.1:1234 3296 3297``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3298 Configure a socket host network backend to share the guest's network 3299 traffic with another QEMU virtual machines using a UDP multicast 3300 socket, effectively making a bus for every QEMU with same multicast 3301 address maddr and port. NOTES: 3302 3303 1. Several QEMU can be running on different hosts and share same bus 3304 (assuming correct multicast setup for these hosts). 3305 3306 2. mcast support is compatible with User Mode Linux (argument 3307 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3308 3309 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3310 3311 Example: 3312 3313 .. parsed-literal:: 3314 3315 # launch one QEMU instance 3316 |qemu_system| linux.img \\ 3317 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3318 -netdev socket,id=n1,mcast=230.0.0.1:1234 3319 # launch another QEMU instance on same "bus" 3320 |qemu_system| linux.img \\ 3321 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3322 -netdev socket,id=n2,mcast=230.0.0.1:1234 3323 # launch yet another QEMU instance on same "bus" 3324 |qemu_system| linux.img \\ 3325 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3326 -netdev socket,id=n3,mcast=230.0.0.1:1234 3327 3328 Example (User Mode Linux compat.): 3329 3330 .. parsed-literal:: 3331 3332 # launch QEMU instance (note mcast address selected is UML's default) 3333 |qemu_system| linux.img \\ 3334 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3335 -netdev socket,id=n1,mcast=239.192.168.1:1102 3336 # launch UML 3337 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3338 3339 Example (send packets from host's 1.2.3.4): 3340 3341 .. parsed-literal:: 3342 3343 |qemu_system| linux.img \\ 3344 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3345 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3346 3347``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 3348 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3349 is a popular protocol to transport Ethernet (and other Layer 2) data 3350 frames between two systems. It is present in routers, firewalls and 3351 the Linux kernel (from version 3.3 onwards). 3352 3353 This transport allows a VM to communicate to another VM, router or 3354 firewall directly. 3355 3356 ``src=srcaddr`` 3357 source address (mandatory) 3358 3359 ``dst=dstaddr`` 3360 destination address (mandatory) 3361 3362 ``udp`` 3363 select udp encapsulation (default is ip). 3364 3365 ``srcport=srcport`` 3366 source udp port. 3367 3368 ``dstport=dstport`` 3369 destination udp port. 3370 3371 ``ipv6`` 3372 force v6, otherwise defaults to v4. 3373 3374 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3375 Cookies are a weak form of security in the l2tpv3 specification. 3376 Their function is mostly to prevent misconfiguration. By default 3377 they are 32 bit. 3378 3379 ``cookie64`` 3380 Set cookie size to 64 bit instead of the default 32 3381 3382 ``counter=off`` 3383 Force a 'cut-down' L2TPv3 with no counter as in 3384 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3385 3386 ``pincounter=on`` 3387 Work around broken counter handling in peer. This may also help 3388 on networks which have packet reorder. 3389 3390 ``offset=offset`` 3391 Add an extra offset between header and data 3392 3393 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3394 the bridge br-lan on the remote Linux host 1.2.3.4: 3395 3396 .. parsed-literal:: 3397 3398 # Setup tunnel on linux host using raw ip as encapsulation 3399 # on 1.2.3.4 3400 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3401 encap udp udp_sport 16384 udp_dport 16384 3402 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3403 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3404 ifconfig vmtunnel0 mtu 1500 3405 ifconfig vmtunnel0 up 3406 brctl addif br-lan vmtunnel0 3407 3408 3409 # on 4.3.2.1 3410 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3411 3412 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3413 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3414 3415``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3416 Configure VDE backend to connect to PORT n of a vde switch running 3417 on host and listening for incoming connections on socketpath. Use 3418 GROUP groupname and MODE octalmode to change default ownership and 3419 permissions for communication port. This option is only available if 3420 QEMU has been compiled with vde support enabled. 3421 3422 Example: 3423 3424 .. parsed-literal:: 3425 3426 # launch vde switch 3427 vde_switch -F -sock /tmp/myswitch 3428 # launch QEMU instance 3429 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3430 3431``-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]`` 3432 Configure AF_XDP backend to connect to a network interface 'name' 3433 using AF_XDP socket. A specific program attach mode for a default 3434 XDP program can be forced with 'mode', defaults to best-effort, 3435 where the likely most performant mode will be in use. Number of queues 3436 'n' should generally match the number or queues in the interface, 3437 defaults to 1. Traffic arriving on non-configured device queues will 3438 not be delivered to the network backend. 3439 3440 .. parsed-literal:: 3441 3442 # set number of queues to 4 3443 ethtool -L eth0 combined 4 3444 # launch QEMU instance 3445 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3446 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3447 3448 'start-queue' option can be specified if a particular range of queues 3449 [m, m + n] should be in use. For example, this is may be necessary in 3450 order to use certain NICs in native mode. Kernel allows the driver to 3451 create a separate set of XDP queues on top of regular ones, and only 3452 these queues can be used for AF_XDP sockets. NICs that work this way 3453 may also require an additional traffic redirection with ethtool to these 3454 special queues. 3455 3456 .. parsed-literal:: 3457 3458 # set number of queues to 1 3459 ethtool -L eth0 combined 1 3460 # redirect all the traffic to the second queue (id: 1) 3461 # note: drivers may require non-empty key/mask pair. 3462 ethtool -N eth0 flow-type ether \\ 3463 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3464 ethtool -N eth0 flow-type ether \\ 3465 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3466 # launch QEMU instance 3467 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3468 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3469 3470 XDP program can also be loaded externally. In this case 'inhibit' option 3471 should be set to 'on' and 'sock-fds' provided with file descriptors for 3472 already open but not bound XDP sockets already added to a socket map for 3473 corresponding queues. One socket per queue. 3474 3475 .. parsed-literal:: 3476 3477 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3478 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3479 3480``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3481 Establish a vhost-user netdev, backed by a chardev id. The chardev 3482 should be a unix domain socket backed one. The vhost-user uses a 3483 specifically defined protocol to pass vhost ioctl replacement 3484 messages to an application on the other end of the socket. On 3485 non-MSIX guests, the feature can be forced with vhostforce. Use 3486 'queues=n' to specify the number of queues to be created for 3487 multiqueue vhost-user. 3488 3489 Example: 3490 3491 :: 3492 3493 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3494 -numa node,memdev=mem \ 3495 -chardev socket,id=chr0,path=/path/to/socket \ 3496 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3497 -device virtio-net-pci,netdev=net0 3498 3499``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3500 Establish a vhost-vdpa netdev. 3501 3502 vDPA device is a device that uses a datapath which complies with 3503 the virtio specifications with a vendor specific control path. 3504 vDPA devices can be both physically located on the hardware or 3505 emulated by software. 3506 3507``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3508 Create a hub port on the emulated hub with ID hubid. 3509 3510 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3511 instead of a single netdev. Alternatively, you can also connect the 3512 hubport to another netdev with ID nd by using the ``netdev=nd`` 3513 option. 3514 3515``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3516 Legacy option to configure or create an on-board (or machine 3517 default) Network Interface Card(NIC) and connect it either to the 3518 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3519 If model is omitted, then the default NIC model associated with the 3520 machine type is used. Note that the default NIC model may change in 3521 future QEMU releases, so it is highly recommended to always specify 3522 a model. Optionally, the MAC address can be changed to mac, the 3523 device address set to addr (PCI cards only), and a name can be 3524 assigned for use in monitor commands. Optionally, for PCI cards, you 3525 can specify the number v of MSI-X vectors that the card should have; 3526 this option currently only affects virtio cards; set v = 0 to 3527 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3528 created. QEMU can emulate several different models of network card. 3529 Use ``-net nic,model=help`` for a list of available devices for your 3530 target. 3531 3532``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3533 Configure a host network backend (with the options corresponding to 3534 the same ``-netdev`` option) and connect it to the emulated hub 0 3535 (the default hub). Use name to specify the name of the hub port. 3536ERST 3537 3538DEFHEADING() 3539 3540DEFHEADING(Character device options:) 3541 3542DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3543 "-chardev help\n" 3544 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3545 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3546 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3547 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3548 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3549 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3550 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3551 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3552 " [,logfile=PATH][,logappend=on|off]\n" 3553 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3554 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3555 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3556 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3557 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3558 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3559#ifdef _WIN32 3560 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3561 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3562#else 3563 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3564 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3565#endif 3566#ifdef CONFIG_BRLAPI 3567 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3568#endif 3569#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3570 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3571 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3572#endif 3573#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3574 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3575#endif 3576#if defined(CONFIG_SPICE) 3577 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3578 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3579#endif 3580 , QEMU_ARCH_ALL 3581) 3582 3583SRST 3584The general form of a character device option is: 3585 3586``-chardev backend,id=id[,mux=on|off][,options]`` 3587 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3588 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3589 ``pty``, ``stdio``, ``braille``, ``parallel``, 3590 ``spicevmc``, ``spiceport``. The specific backend will determine the 3591 applicable options. 3592 3593 Use ``-chardev help`` to print all available chardev backend types. 3594 3595 All devices must have an id, which can be any string up to 127 3596 characters long. It is used to uniquely identify this device in 3597 other command line directives. 3598 3599 A character device may be used in multiplexing mode by multiple 3600 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3601 a "1:N" device, and here the "1" end is your specified chardev 3602 backend, and the "N" end is the various parts of QEMU that can talk 3603 to a chardev. If you create a chardev with ``id=myid`` and 3604 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3605 and you can then configure multiple front ends to use that chardev 3606 ID for their input/output. Up to four different front ends can be 3607 connected to a single multiplexed chardev. (Without multiplexing 3608 enabled, a chardev can only be used by a single front end.) For 3609 instance you could use this to allow a single stdio chardev to be 3610 used by two serial ports and the QEMU monitor: 3611 3612 :: 3613 3614 -chardev stdio,mux=on,id=char0 \ 3615 -mon chardev=char0,mode=readline \ 3616 -serial chardev:char0 \ 3617 -serial chardev:char0 3618 3619 You can have more than one multiplexer in a system configuration; 3620 for instance you could have a TCP port multiplexed between UART 0 3621 and UART 1, and stdio multiplexed between the QEMU monitor and a 3622 parallel port: 3623 3624 :: 3625 3626 -chardev stdio,mux=on,id=char0 \ 3627 -mon chardev=char0,mode=readline \ 3628 -parallel chardev:char0 \ 3629 -chardev tcp,...,mux=on,id=char1 \ 3630 -serial chardev:char1 \ 3631 -serial chardev:char1 3632 3633 When you're using a multiplexed character device, some escape 3634 sequences are interpreted in the input. See the chapter about 3635 :ref:`keys in the character backend multiplexer` in the 3636 System Emulation Users Guide for more details. 3637 3638 Note that some other command line options may implicitly create 3639 multiplexed character backends; for instance ``-serial mon:stdio`` 3640 creates a multiplexed stdio backend connected to the serial port and 3641 the QEMU monitor, and ``-nographic`` also multiplexes the console 3642 and the monitor to stdio. 3643 3644 There is currently no support for multiplexing in the other 3645 direction (where a single QEMU front end takes input and output from 3646 multiple chardevs). 3647 3648 Every backend supports the ``logfile`` option, which supplies the 3649 path to a file to record all data transmitted via the backend. The 3650 ``logappend`` option controls whether the log file will be truncated 3651 or appended to when opened. 3652 3653The available backends are: 3654 3655``-chardev null,id=id`` 3656 A void device. This device will not emit any data, and will drop any 3657 data it receives. The null backend does not take any options. 3658 3659``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3660 Create a two-way stream socket, which can be either a TCP or a unix 3661 socket. A unix socket will be created if ``path`` is specified. 3662 Behaviour is undefined if TCP options are specified for a unix 3663 socket. 3664 3665 ``server=on|off`` specifies that the socket shall be a listening socket. 3666 3667 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3668 to connect to a listening socket. 3669 3670 ``telnet=on|off`` specifies that traffic on the socket should interpret 3671 telnet escape sequences. 3672 3673 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3674 communication. 3675 3676 ``reconnect`` sets the timeout for reconnecting on non-server 3677 sockets when the remote end goes away. qemu will delay this many 3678 seconds and then attempt to reconnect. Zero disables reconnecting, 3679 and is the default. 3680 3681 ``tls-creds`` requests enablement of the TLS protocol for 3682 encryption, and specifies the id of the TLS credentials to use for 3683 the handshake. The credentials must be previously created with the 3684 ``-object tls-creds`` argument. 3685 3686 ``tls-auth`` provides the ID of the QAuthZ authorization object 3687 against which the client's x509 distinguished name will be 3688 validated. This object is only resolved at time of use, so can be 3689 deleted and recreated on the fly while the chardev server is active. 3690 If missing, it will default to denying access. 3691 3692 TCP and unix socket options are given below: 3693 3694 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3695 ``host`` for a listening socket specifies the local address to 3696 be bound. For a connecting socket species the remote host to 3697 connect to. ``host`` is optional for listening sockets. If not 3698 specified it defaults to ``0.0.0.0``. 3699 3700 ``port`` for a listening socket specifies the local port to be 3701 bound. For a connecting socket specifies the port on the remote 3702 host to connect to. ``port`` can be given as either a port 3703 number or a service name. ``port`` is required. 3704 3705 ``to`` is only relevant to listening sockets. If it is 3706 specified, and ``port`` cannot be bound, QEMU will attempt to 3707 bind to subsequent ports up to and including ``to`` until it 3708 succeeds. ``to`` must be specified as a port number. 3709 3710 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3711 or IPv6 must be used. If neither is specified the socket may 3712 use either protocol. 3713 3714 ``nodelay=on|off`` disables the Nagle algorithm. 3715 3716 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3717 ``path`` specifies the local path of the unix socket. ``path`` 3718 is required. 3719 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3720 rather than the filesystem. Optional, defaults to false. 3721 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3722 rather than the full sun_path length. Optional, defaults to true. 3723 3724``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3725 Sends all traffic from the guest to a remote host over UDP. 3726 3727 ``host`` specifies the remote host to connect to. If not specified 3728 it defaults to ``localhost``. 3729 3730 ``port`` specifies the port on the remote host to connect to. 3731 ``port`` is required. 3732 3733 ``localaddr`` specifies the local address to bind to. If not 3734 specified it defaults to ``0.0.0.0``. 3735 3736 ``localport`` specifies the local port to bind to. If not specified 3737 any available local port will be used. 3738 3739 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3740 If neither is specified the device may use either protocol. 3741 3742``-chardev msmouse,id=id`` 3743 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3744 does not take any options. 3745 3746``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3747 Connect to a QEMU text console. ``vc`` may optionally be given a 3748 specific size. 3749 3750 ``width`` and ``height`` specify the width and height respectively 3751 of the console, in pixels. 3752 3753 ``cols`` and ``rows`` specify that the console be sized to fit a 3754 text console with the given dimensions. 3755 3756``-chardev ringbuf,id=id[,size=size]`` 3757 Create a ring buffer with fixed size ``size``. size must be a power 3758 of two and defaults to ``64K``. 3759 3760``-chardev file,id=id,path=path[,input-path=input-path]`` 3761 Log all traffic received from the guest to a file. 3762 3763 ``path`` specifies the path of the file to be opened. This file will 3764 be created if it does not already exist, and overwritten if it does. 3765 ``path`` is required. 3766 3767 If ``input-path`` is specified, this is the path of a second file 3768 which will be used for input. If ``input-path`` is not specified, 3769 no input will be available from the chardev. 3770 3771 Note that ``input-path`` is not supported on Windows hosts. 3772 3773``-chardev pipe,id=id,path=path`` 3774 Create a two-way connection to the guest. The behaviour differs 3775 slightly between Windows hosts and other hosts: 3776 3777 On Windows, a single duplex pipe will be created at 3778 ``\\.pipe\path``. 3779 3780 On other hosts, 2 pipes will be created called ``path.in`` and 3781 ``path.out``. Data written to ``path.in`` will be received by the 3782 guest. Data written by the guest can be read from ``path.out``. QEMU 3783 will not create these fifos, and requires them to be present. 3784 3785 ``path`` forms part of the pipe path as described above. ``path`` is 3786 required. 3787 3788``-chardev console,id=id`` 3789 Send traffic from the guest to QEMU's standard output. ``console`` 3790 does not take any options. 3791 3792 ``console`` is only available on Windows hosts. 3793 3794``-chardev serial,id=id,path=path`` 3795 Send traffic from the guest to a serial device on the host. 3796 3797 On Unix hosts serial will actually accept any tty device, not only 3798 serial lines. 3799 3800 ``path`` specifies the name of the serial device to open. 3801 3802``-chardev pty,id=id`` 3803 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3804 does not take any options. 3805 3806 ``pty`` is not available on Windows hosts. 3807 3808``-chardev stdio,id=id[,signal=on|off]`` 3809 Connect to standard input and standard output of the QEMU process. 3810 3811 ``signal`` controls if signals are enabled on the terminal, that 3812 includes exiting QEMU with the key sequence Control-c. This option 3813 is enabled by default, use ``signal=off`` to disable it. 3814 3815``-chardev braille,id=id`` 3816 Connect to a local BrlAPI server. ``braille`` does not take any 3817 options. 3818 3819``-chardev parallel,id=id,path=path`` 3820 \ 3821 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3822 hosts. 3823 3824 Connect to a local parallel port. 3825 3826 ``path`` specifies the path to the parallel port device. ``path`` is 3827 required. 3828 3829``-chardev spicevmc,id=id,debug=debug,name=name`` 3830 ``spicevmc`` is only available when spice support is built in. 3831 3832 ``debug`` debug level for spicevmc 3833 3834 ``name`` name of spice channel to connect to 3835 3836 Connect to a spice virtual machine channel, such as vdiport. 3837 3838``-chardev spiceport,id=id,debug=debug,name=name`` 3839 ``spiceport`` is only available when spice support is built in. 3840 3841 ``debug`` debug level for spicevmc 3842 3843 ``name`` name of spice port to connect to 3844 3845 Connect to a spice port, allowing a Spice client to handle the 3846 traffic identified by a name (preferably a fqdn). 3847ERST 3848 3849DEFHEADING() 3850 3851#ifdef CONFIG_TPM 3852DEFHEADING(TPM device options:) 3853 3854DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3855 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3856 " use path to provide path to a character device; default is /dev/tpm0\n" 3857 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3858 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3859 "-tpmdev emulator,id=id,chardev=dev\n" 3860 " configure the TPM device using chardev backend\n", 3861 QEMU_ARCH_ALL) 3862SRST 3863The general form of a TPM device option is: 3864 3865``-tpmdev backend,id=id[,options]`` 3866 The specific backend type will determine the applicable options. The 3867 ``-tpmdev`` option creates the TPM backend and requires a 3868 ``-device`` option that specifies the TPM frontend interface model. 3869 3870 Use ``-tpmdev help`` to print all available TPM backend types. 3871 3872The available backends are: 3873 3874``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3875 (Linux-host only) Enable access to the host's TPM using the 3876 passthrough driver. 3877 3878 ``path`` specifies the path to the host's TPM device, i.e., on a 3879 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3880 default ``/dev/tpm0`` is used. 3881 3882 ``cancel-path`` specifies the path to the host TPM device's sysfs 3883 entry allowing for cancellation of an ongoing TPM command. 3884 ``cancel-path`` is optional and by default QEMU will search for the 3885 sysfs entry to use. 3886 3887 Some notes about using the host's TPM with the passthrough driver: 3888 3889 The TPM device accessed by the passthrough driver must not be used 3890 by any other application on the host. 3891 3892 Since the host's firmware (BIOS/UEFI) has already initialized the 3893 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3894 the TPM again and may therefore not show a TPM-specific menu that 3895 would otherwise allow the user to configure the TPM, e.g., allow the 3896 user to enable/disable or activate/deactivate the TPM. Further, if 3897 TPM ownership is released from within a VM then the host's TPM will 3898 get disabled and deactivated. To enable and activate the TPM again 3899 afterwards, the host has to be rebooted and the user is required to 3900 enter the firmware's menu to enable and activate the TPM. If the TPM 3901 is left disabled and/or deactivated most TPM commands will fail. 3902 3903 To create a passthrough TPM use the following two options: 3904 3905 :: 3906 3907 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3908 3909 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3910 ``tpmdev=tpm0`` in the device option. 3911 3912``-tpmdev emulator,id=id,chardev=dev`` 3913 (Linux-host only) Enable access to a TPM emulator using Unix domain 3914 socket based chardev backend. 3915 3916 ``chardev`` specifies the unique ID of a character device backend 3917 that provides connection to the software TPM server. 3918 3919 To create a TPM emulator backend device with chardev socket backend: 3920 3921 :: 3922 3923 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3924ERST 3925 3926DEFHEADING() 3927 3928#endif 3929 3930DEFHEADING(Boot Image or Kernel specific:) 3931SRST 3932There are broadly 4 ways you can boot a system with QEMU. 3933 3934 - specify a firmware and let it control finding a kernel 3935 - specify a firmware and pass a hint to the kernel to boot 3936 - direct kernel image boot 3937 - manually load files into the guest's address space 3938 3939The third method is useful for quickly testing kernels but as there is 3940no firmware to pass configuration information to the kernel the 3941hardware must either be probeable, the kernel built for the exact 3942configuration or passed some configuration data (e.g. a DTB blob) 3943which tells the kernel what drivers it needs. This exact details are 3944often hardware specific. 3945 3946The final method is the most generic way of loading images into the 3947guest address space and used mostly for ``bare metal`` type 3948development where the reset vectors of the processor are taken into 3949account. 3950 3951ERST 3952 3953SRST 3954 3955For x86 machines and some other architectures ``-bios`` will generally 3956do the right thing with whatever it is given. For other machines the 3957more strict ``-pflash`` option needs an image that is sized for the 3958flash device for the given machine type. 3959 3960Please see the :ref:`system-targets-ref` section of the manual for 3961more detailed documentation. 3962 3963ERST 3964 3965DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3966 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3967SRST 3968``-bios file`` 3969 Set the filename for the BIOS. 3970ERST 3971 3972DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3973 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3974SRST 3975``-pflash file`` 3976 Use file as a parallel flash image. 3977ERST 3978 3979SRST 3980 3981The kernel options were designed to work with Linux kernels although 3982other things (like hypervisors) can be packaged up as a kernel 3983executable image. The exact format of a executable image is usually 3984architecture specific. 3985 3986The way in which the kernel is started (what address it is loaded at, 3987what if any information is passed to it via CPU registers, the state 3988of the hardware when it is started, and so on) is also architecture 3989specific. Typically it follows the specification laid down by the 3990Linux kernel for how kernels for that architecture must be started. 3991 3992ERST 3993 3994DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3995 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3996SRST 3997``-kernel bzImage`` 3998 Use bzImage as kernel image. The kernel can be either a Linux kernel 3999 or in multiboot format. 4000ERST 4001 4002DEF("append", HAS_ARG, QEMU_OPTION_append, \ 4003 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 4004SRST 4005``-append cmdline`` 4006 Use cmdline as kernel command line 4007ERST 4008 4009DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4010 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4011SRST(initrd) 4012 4013``-initrd file`` 4014 Use file as initial ram disk. 4015 4016``-initrd "file1 arg=foo,file2"`` 4017 This syntax is only available with multiboot. 4018 4019 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4020 first module. Commas can be provided in module parameters by doubling 4021 them on the command line to escape them: 4022 4023``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4024 Multiboot only. Use bzImage as the first module with 4025 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4026 and initrd.img as the second module. 4027 4028ERST 4029 4030DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4031 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4032SRST 4033``-dtb file`` 4034 Use file as a device tree binary (dtb) image and pass it to the 4035 kernel on boot. 4036ERST 4037 4038SRST 4039 4040Finally you can also manually load images directly into the address 4041space of the guest. This is most useful for developers who already 4042know the layout of their guest and take care to ensure something sane 4043will happen when the reset vector executes. 4044 4045The generic loader can be invoked by using the loader device: 4046 4047``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4048 4049there is also the guest loader which operates in a similar way but 4050tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4051the guest image is: 4052 4053``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4054 4055ERST 4056 4057DEFHEADING() 4058 4059DEFHEADING(Debug/Expert options:) 4060 4061DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4062 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4063 " Policy for handling deprecated management interfaces\n" 4064 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4065 " Policy for handling unstable management interfaces\n", 4066 QEMU_ARCH_ALL) 4067SRST 4068``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4069 Set policy for handling deprecated management interfaces (experimental): 4070 4071 ``deprecated-input=accept`` (default) 4072 Accept deprecated commands and arguments 4073 ``deprecated-input=reject`` 4074 Reject deprecated commands and arguments 4075 ``deprecated-input=crash`` 4076 Crash on deprecated commands and arguments 4077 ``deprecated-output=accept`` (default) 4078 Emit deprecated command results and events 4079 ``deprecated-output=hide`` 4080 Suppress deprecated command results and events 4081 4082 Limitation: covers only syntactic aspects of QMP. 4083 4084``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4085 Set policy for handling unstable management interfaces (experimental): 4086 4087 ``unstable-input=accept`` (default) 4088 Accept unstable commands and arguments 4089 ``unstable-input=reject`` 4090 Reject unstable commands and arguments 4091 ``unstable-input=crash`` 4092 Crash on unstable commands and arguments 4093 ``unstable-output=accept`` (default) 4094 Emit unstable command results and events 4095 ``unstable-output=hide`` 4096 Suppress unstable command results and events 4097 4098 Limitation: covers only syntactic aspects of QMP. 4099ERST 4100 4101DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4102 "-fw_cfg [name=]<name>,file=<file>\n" 4103 " add named fw_cfg entry with contents from file\n" 4104 "-fw_cfg [name=]<name>,string=<str>\n" 4105 " add named fw_cfg entry with contents from string\n", 4106 QEMU_ARCH_ALL) 4107SRST 4108``-fw_cfg [name=]name,file=file`` 4109 Add named fw\_cfg entry with contents from file file. 4110 If the filename contains comma, you must double it (for instance, 4111 "file=my,,file" to use file "my,file"). 4112 4113``-fw_cfg [name=]name,string=str`` 4114 Add named fw\_cfg entry with contents from string str. 4115 If the string contains comma, you must double it (for instance, 4116 "string=my,,string" to use file "my,string"). 4117 4118 The terminating NUL character of the contents of str will not be 4119 included as part of the fw\_cfg item data. To insert contents with 4120 embedded NUL characters, you have to use the file parameter. 4121 4122 The fw\_cfg entries are passed by QEMU through to the guest. 4123 4124 Example: 4125 4126 :: 4127 4128 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4129 4130 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4131 from ./my\_blob.bin. 4132ERST 4133 4134DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4135 "-serial dev redirect the serial port to char device 'dev'\n", 4136 QEMU_ARCH_ALL) 4137SRST 4138``-serial dev`` 4139 Redirect the virtual serial port to host character device dev. The 4140 default device is ``vc`` in graphical mode and ``stdio`` in non 4141 graphical mode. 4142 4143 This option can be used several times to simulate multiple serial 4144 ports. 4145 4146 You can use ``-serial none`` to suppress the creation of default 4147 serial devices. 4148 4149 Available character devices are: 4150 4151 ``vc[:WxH]`` 4152 Virtual console. Optionally, a width and height can be given in 4153 pixel with 4154 4155 :: 4156 4157 vc:800x600 4158 4159 It is also possible to specify width or height in characters: 4160 4161 :: 4162 4163 vc:80Cx24C 4164 4165 ``pty`` 4166 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4167 4168 ``none`` 4169 No device is allocated. Note that for machine types which 4170 emulate systems where a serial device is always present in 4171 real hardware, this may be equivalent to the ``null`` option, 4172 in that the serial device is still present but all output 4173 is discarded. For boards where the number of serial ports is 4174 truly variable, this suppresses the creation of the device. 4175 4176 ``null`` 4177 A guest will see the UART or serial device as present in the 4178 machine, but all output is discarded, and there is no input. 4179 Conceptually equivalent to redirecting the output to ``/dev/null``. 4180 4181 ``chardev:id`` 4182 Use a named character device defined with the ``-chardev`` 4183 option. 4184 4185 ``/dev/XXX`` 4186 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4187 port parameters are set according to the emulated ones. 4188 4189 ``/dev/parportN`` 4190 [Linux only, parallel port only] Use host parallel port N. 4191 Currently SPP and EPP parallel port features can be used. 4192 4193 ``file:filename`` 4194 Write output to filename. No character can be read. 4195 4196 ``stdio`` 4197 [Unix only] standard input/output 4198 4199 ``pipe:filename`` 4200 name pipe filename 4201 4202 ``COMn`` 4203 [Windows only] Use host serial port n 4204 4205 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4206 This implements UDP Net Console. When remote\_host or src\_ip 4207 are not specified they default to ``0.0.0.0``. When not using a 4208 specified src\_port a random port is automatically chosen. 4209 4210 If you just want a simple readonly console you can use 4211 ``netcat`` or ``nc``, by starting QEMU with: 4212 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4213 QEMU writes something to that port it will appear in the 4214 netconsole session. 4215 4216 If you plan to send characters back via netconsole or you want 4217 to stop and start QEMU a lot of times, you should have QEMU use 4218 the same source port each time by using something like ``-serial 4219 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4220 version of netcat which can listen to a TCP port and send and 4221 receive characters via udp. If you have a patched version of 4222 netcat which activates telnet remote echo and single char 4223 transfer, then you can use the following options to set up a 4224 netcat redirector to allow telnet on port 5555 to access the 4225 QEMU port. 4226 4227 ``QEMU Options:`` 4228 -serial udp::4555@:4556 4229 4230 ``netcat options:`` 4231 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4232 4233 ``telnet options:`` 4234 localhost 5555 4235 4236 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4237 The TCP Net Console has two modes of operation. It can send the 4238 serial I/O to a location or wait for a connection from a 4239 location. By default the TCP Net Console is sent to host at the 4240 port. If you use the ``server=on`` option QEMU will wait for a client 4241 socket application to connect to the port before continuing, 4242 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4243 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4244 option only applies if ``server=no`` is set, if the connection goes 4245 down it will attempt to reconnect at the given interval. If host 4246 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4247 time is accepted. You can use ``telnet=on`` to connect to the 4248 corresponding character device. 4249 4250 ``Example to send tcp console to 192.168.0.2 port 4444`` 4251 -serial tcp:192.168.0.2:4444 4252 4253 ``Example to listen and wait on port 4444 for connection`` 4254 -serial tcp::4444,server=on 4255 4256 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4257 -serial tcp:192.168.0.100:4444,server=on,wait=off 4258 4259 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4260 The telnet protocol is used instead of raw tcp sockets. The 4261 options work the same as if you had specified ``-serial tcp``. 4262 The difference is that the port acts like a telnet server or 4263 client using telnet option negotiation. This will also allow you 4264 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4265 supports sending the break sequence. Typically in unix telnet 4266 you do it with Control-] and then type "send break" followed by 4267 pressing the enter key. 4268 4269 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4270 The WebSocket protocol is used instead of raw tcp socket. The 4271 port acts as a WebSocket server. Client mode is not supported. 4272 4273 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4274 A unix domain socket is used instead of a tcp socket. The option 4275 works the same as if you had specified ``-serial tcp`` except 4276 the unix domain socket path is used for connections. 4277 4278 ``mon:dev_string`` 4279 This is a special option to allow the monitor to be multiplexed 4280 onto another serial port. The monitor is accessed with key 4281 sequence of Control-a and then pressing c. dev\_string should be 4282 any one of the serial devices specified above. An example to 4283 multiplex the monitor onto a telnet server listening on port 4284 4444 would be: 4285 4286 ``-serial mon:telnet::4444,server=on,wait=off`` 4287 4288 When the monitor is multiplexed to stdio in this way, Ctrl+C 4289 will not terminate QEMU any more but will be passed to the guest 4290 instead. 4291 4292 ``braille`` 4293 Braille device. This will use BrlAPI to display the braille 4294 output on a real or fake device. 4295 4296 ``msmouse`` 4297 Three button serial mouse. Configure the guest to use Microsoft 4298 protocol. 4299ERST 4300 4301DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4302 "-parallel dev redirect the parallel port to char device 'dev'\n", 4303 QEMU_ARCH_ALL) 4304SRST 4305``-parallel dev`` 4306 Redirect the virtual parallel port to host device dev (same devices 4307 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4308 to use hardware devices connected on the corresponding host parallel 4309 port. 4310 4311 This option can be used several times to simulate up to 3 parallel 4312 ports. 4313 4314 Use ``-parallel none`` to disable all parallel ports. 4315ERST 4316 4317DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4318 "-monitor dev redirect the monitor to char device 'dev'\n", 4319 QEMU_ARCH_ALL) 4320SRST 4321``-monitor dev`` 4322 Redirect the monitor to host device dev (same devices as the serial 4323 port). The default device is ``vc`` in graphical mode and ``stdio`` 4324 in non graphical mode. Use ``-monitor none`` to disable the default 4325 monitor. 4326ERST 4327DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4328 "-qmp dev like -monitor but opens in 'control' mode\n", 4329 QEMU_ARCH_ALL) 4330SRST 4331``-qmp dev`` 4332 Like ``-monitor`` but opens in 'control' mode. For example, to make 4333 QMP available on localhost port 4444:: 4334 4335 -qmp tcp:localhost:4444,server=on,wait=off 4336 4337 Not all options are configurable via this syntax; for maximum 4338 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4339 4340ERST 4341DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4342 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4343 QEMU_ARCH_ALL) 4344SRST 4345``-qmp-pretty dev`` 4346 Like ``-qmp`` but uses pretty JSON formatting. 4347ERST 4348 4349DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4350 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4351SRST 4352``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4353 Set up a monitor connected to the chardev ``name``. 4354 QEMU supports two monitors: the Human Monitor Protocol 4355 (HMP; for human interaction), and the QEMU Monitor Protocol 4356 (QMP; a JSON RPC-style protocol). 4357 The default is HMP; ``mode=control`` selects QMP instead. 4358 ``pretty`` is only valid when ``mode=control``, 4359 turning on JSON pretty printing to ease 4360 human reading and debugging. 4361 4362 For example:: 4363 4364 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4365 -mon chardev=mon1,mode=control,pretty=on 4366 4367 enables the QMP monitor on localhost port 4444 with pretty-printing. 4368ERST 4369 4370DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4371 "-debugcon dev redirect the debug console to char device 'dev'\n", 4372 QEMU_ARCH_ALL) 4373SRST 4374``-debugcon dev`` 4375 Redirect the debug console to host device dev (same devices as the 4376 serial port). The debug console is an I/O port which is typically 4377 port 0xe9; writing to that I/O port sends output to this device. The 4378 default device is ``vc`` in graphical mode and ``stdio`` in non 4379 graphical mode. 4380ERST 4381 4382DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4383 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4384SRST 4385``-pidfile file`` 4386 Store the QEMU process PID in file. It is useful if you launch QEMU 4387 from a script. 4388ERST 4389 4390DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4391 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4392 QEMU_ARCH_ALL) 4393SRST 4394``--preconfig`` 4395 Pause QEMU for interactive configuration before the machine is 4396 created, which allows querying and configuring properties that will 4397 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4398 exit the preconfig state and move to the next state (i.e. run guest 4399 if -S isn't used or pause the second time if -S is used). This 4400 option is experimental. 4401ERST 4402 4403DEF("S", 0, QEMU_OPTION_S, \ 4404 "-S freeze CPU at startup (use 'c' to start execution)\n", 4405 QEMU_ARCH_ALL) 4406SRST 4407``-S`` 4408 Do not start CPU at startup (you must type 'c' in the monitor). 4409ERST 4410 4411DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4412 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4413 " run qemu with overcommit hints\n" 4414 " mem-lock=on|off controls memory lock support (default: off)\n" 4415 " cpu-pm=on|off controls cpu power management (default: off)\n", 4416 QEMU_ARCH_ALL) 4417SRST 4418``-overcommit mem-lock=on|off`` 4419 \ 4420``-overcommit cpu-pm=on|off`` 4421 Run qemu with hints about host resource overcommit. The default is 4422 to assume that host overcommits all resources. 4423 4424 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4425 (disabled by default). This works when host memory is not 4426 overcommitted and reduces the worst-case latency for guest. 4427 4428 Guest ability to manage power state of host cpus (increasing latency 4429 for other processes on the same host cpu, but decreasing latency for 4430 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4431 works best when host CPU is not overcommitted. When used, host 4432 estimates of CPU cycle and power utilization will be incorrect, not 4433 taking into account guest idle time. 4434ERST 4435 4436DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4437 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4438 " the guest without waiting for gdb to connect; use -S too\n" 4439 " if you want it to not start execution.)\n", 4440 QEMU_ARCH_ALL) 4441SRST 4442``-gdb dev`` 4443 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4444 in the System Emulation Users Guide). Note that this option does not pause QEMU 4445 execution -- if you want QEMU to not start the guest until you 4446 connect with gdb and issue a ``continue`` command, you will need to 4447 also pass the ``-S`` option to QEMU. 4448 4449 The most usual configuration is to listen on a local TCP socket:: 4450 4451 -gdb tcp::3117 4452 4453 but you can specify other backends; UDP, pseudo TTY, or even stdio 4454 are all reasonable use cases. For example, a stdio connection 4455 allows you to start QEMU from within gdb and establish the 4456 connection via a pipe: 4457 4458 .. parsed-literal:: 4459 4460 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4461ERST 4462 4463DEF("s", 0, QEMU_OPTION_s, \ 4464 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4465 QEMU_ARCH_ALL) 4466SRST 4467``-s`` 4468 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4469 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4470ERST 4471 4472DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4473 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4474 QEMU_ARCH_ALL) 4475SRST 4476``-d item1[,...]`` 4477 Enable logging of specified items. Use '-d help' for a list of log 4478 items. 4479ERST 4480 4481DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4482 "-D logfile output log to logfile (default stderr)\n", 4483 QEMU_ARCH_ALL) 4484SRST 4485``-D logfile`` 4486 Output log in logfile instead of to stderr 4487ERST 4488 4489DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4490 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4491 QEMU_ARCH_ALL) 4492SRST 4493``-dfilter range1[,...]`` 4494 Filter debug output to that relevant to a range of target addresses. 4495 The filter spec can be either start+size, start-size or start..end 4496 where start end and size are the addresses and sizes required. For 4497 example: 4498 4499 :: 4500 4501 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4502 4503 Will dump output for any code in the 0x1000 sized block starting at 4504 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4505 another 0x1000 sized block starting at 0xffffffc00005f000. 4506ERST 4507 4508DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4509 "-seed number seed the pseudo-random number generator\n", 4510 QEMU_ARCH_ALL) 4511SRST 4512``-seed number`` 4513 Force the guest to use a deterministic pseudo-random number 4514 generator, seeded with number. This does not affect crypto routines 4515 within the host. 4516ERST 4517 4518DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4519 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4520 QEMU_ARCH_ALL) 4521SRST 4522``-L path`` 4523 Set the directory for the BIOS, VGA BIOS and keymaps. 4524 4525 To list all the data directories, use ``-L help``. 4526ERST 4527 4528DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4529 "-enable-kvm enable KVM full virtualization support\n", 4530 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4531 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4532SRST 4533``-enable-kvm`` 4534 Enable KVM full virtualization support. This option is only 4535 available if KVM support is enabled when compiling. 4536ERST 4537 4538DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4539 "-xen-domid id specify xen guest domain id\n", 4540 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4541DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4542 "-xen-attach attach to existing xen domain\n" 4543 " libxl will use this when starting QEMU\n", 4544 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4545DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4546 "-xen-domid-restrict restrict set of available xen operations\n" 4547 " to specified domain id. (Does not affect\n" 4548 " xenpv machine type).\n", 4549 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4550SRST 4551``-xen-domid id`` 4552 Specify xen guest domain id (XEN only). 4553 4554``-xen-attach`` 4555 Attach to existing xen domain. libxl will use this when starting 4556 QEMU (XEN only). Restrict set of available xen operations to 4557 specified domain id (XEN only). 4558ERST 4559 4560DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4561 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4562SRST 4563``-no-reboot`` 4564 Exit instead of rebooting. 4565ERST 4566 4567DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4568 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4569SRST 4570``-no-shutdown`` 4571 Don't exit QEMU on guest shutdown, but instead only stop the 4572 emulation. This allows for instance switching to monitor to commit 4573 changes to the disk image. 4574ERST 4575 4576DEF("action", HAS_ARG, QEMU_OPTION_action, 4577 "-action reboot=reset|shutdown\n" 4578 " action when guest reboots [default=reset]\n" 4579 "-action shutdown=poweroff|pause\n" 4580 " action when guest shuts down [default=poweroff]\n" 4581 "-action panic=pause|shutdown|exit-failure|none\n" 4582 " action when guest panics [default=shutdown]\n" 4583 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4584 " action when watchdog fires [default=reset]\n", 4585 QEMU_ARCH_ALL) 4586SRST 4587``-action event=action`` 4588 The action parameter serves to modify QEMU's default behavior when 4589 certain guest events occur. It provides a generic method for specifying the 4590 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4591 parameters. 4592 4593 Examples: 4594 4595 ``-action panic=none`` 4596 ``-action reboot=shutdown,shutdown=pause`` 4597 ``-device i6300esb -action watchdog=pause`` 4598 4599ERST 4600 4601DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4602 "-loadvm [tag|id]\n" \ 4603 " start right away with a saved state (loadvm in monitor)\n", 4604 QEMU_ARCH_ALL) 4605SRST 4606``-loadvm file`` 4607 Start right away with a saved state (``loadvm`` in monitor) 4608ERST 4609 4610#ifndef _WIN32 4611DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4612 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4613#endif 4614SRST 4615``-daemonize`` 4616 Daemonize the QEMU process after initialization. QEMU will not 4617 detach from standard IO until it is ready to receive connections on 4618 any of its devices. This option is a useful way for external 4619 programs to launch QEMU without having to cope with initialization 4620 race conditions. 4621ERST 4622 4623DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4624 "-option-rom rom load a file, rom, into the option ROM space\n", 4625 QEMU_ARCH_ALL) 4626SRST 4627``-option-rom file`` 4628 Load the contents of file as an option ROM. This option is useful to 4629 load things like EtherBoot. 4630ERST 4631 4632DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4633 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4634 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4635 QEMU_ARCH_ALL) 4636 4637SRST 4638``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4639 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4640 the current UTC or local time, respectively. ``localtime`` is 4641 required for correct date in MS-DOS or Windows. To start at a 4642 specific point in time, provide datetime in the format 4643 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4644 4645 By default the RTC is driven by the host system time. This allows 4646 using of the RTC as accurate reference clock inside the guest, 4647 specifically if the host time is smoothly following an accurate 4648 external reference clock, e.g. via NTP. If you want to isolate the 4649 guest time from the host, you can set ``clock`` to ``rt`` instead, 4650 which provides a host monotonic clock if host support it. To even 4651 prevent the RTC from progressing during suspension, you can set 4652 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4653 recommended especially in icount mode in order to preserve 4654 determinism; however, note that in icount mode the speed of the 4655 virtual clock is variable and can in general differ from the host 4656 clock. 4657 4658 Enable ``driftfix`` (i386 targets only) if you experience time drift 4659 problems, specifically with Windows' ACPI HAL. This option will try 4660 to figure out how many timer interrupts were not processed by the 4661 Windows guest and will re-inject them. 4662ERST 4663 4664DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4665 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4666 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4667 " instruction, enable aligning the host and virtual clocks\n" \ 4668 " or disable real time cpu sleeping, and optionally enable\n" \ 4669 " record-and-replay mode\n", QEMU_ARCH_ALL) 4670SRST 4671``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4672 Enable virtual instruction counter. The virtual cpu will execute one 4673 instruction every 2^N ns of virtual time. If ``auto`` is specified 4674 then the virtual cpu speed will be automatically adjusted to keep 4675 virtual time within a few seconds of real time. 4676 4677 Note that while this option can give deterministic behavior, it does 4678 not provide cycle accurate emulation. Modern CPUs contain 4679 superscalar out of order cores with complex cache hierarchies. The 4680 number of instructions executed often has little or no correlation 4681 with actual performance. 4682 4683 When the virtual cpu is sleeping, the virtual time will advance at 4684 default speed unless ``sleep=on`` is specified. With 4685 ``sleep=on``, the virtual time will jump to the next timer 4686 deadline instantly whenever the virtual cpu goes to sleep mode and 4687 will not advance if no timer is enabled. This behavior gives 4688 deterministic execution times from the guest point of view. 4689 The default if icount is enabled is ``sleep=off``. 4690 ``sleep=on`` cannot be used together with either ``shift=auto`` 4691 or ``align=on``. 4692 4693 ``align=on`` will activate the delay algorithm which will try to 4694 synchronise the host clock and the virtual clock. The goal is to 4695 have a guest running at the real frequency imposed by the shift 4696 option. Whenever the guest clock is behind the host clock and if 4697 ``align=on`` is specified then we print a message to the user to 4698 inform about the delay. Currently this option does not work when 4699 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4700 shift values for which the guest clock runs ahead of the host clock. 4701 Typically this happens when the shift value is high (how high 4702 depends on the host machine). The default if icount is enabled 4703 is ``align=off``. 4704 4705 When the ``rr`` option is specified deterministic record/replay is 4706 enabled. The ``rrfile=`` option must also be provided to 4707 specify the path to the replay log. In record mode data is written 4708 to this file, and in replay mode it is read back. 4709 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4710 name. In record mode, a new VM snapshot with the given name is created 4711 at the start of execution recording. In replay mode this option 4712 specifies the snapshot name used to load the initial VM state. 4713ERST 4714 4715DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4716 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4717 " action when watchdog fires [default=reset]\n", 4718 QEMU_ARCH_ALL) 4719SRST 4720``-watchdog-action action`` 4721 The action controls what QEMU will do when the watchdog timer 4722 expires. The default is ``reset`` (forcefully reset the guest). 4723 Other possible actions are: ``shutdown`` (attempt to gracefully 4724 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4725 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4726 guest), ``debug`` (print a debug message and continue), or ``none`` 4727 (do nothing). 4728 4729 Note that the ``shutdown`` action requires that the guest responds 4730 to ACPI signals, which it may not be able to do in the sort of 4731 situations where the watchdog would have expired, and thus 4732 ``-watchdog-action shutdown`` is not recommended for production use. 4733 4734 Examples: 4735 4736 ``-device i6300esb -watchdog-action pause`` 4737 4738ERST 4739 4740DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4741 "-echr chr set terminal escape character instead of ctrl-a\n", 4742 QEMU_ARCH_ALL) 4743SRST 4744``-echr numeric_ascii_value`` 4745 Change the escape character used for switching to the monitor when 4746 using monitor and serial sharing. The default is ``0x01`` when using 4747 the ``-nographic`` option. ``0x01`` is equal to pressing 4748 ``Control-a``. You can select a different character from the ascii 4749 control keys where 1 through 26 map to Control-a through Control-z. 4750 For instance you could use the either of the following to change the 4751 escape character to Control-t. 4752 4753 ``-echr 0x14``; \ ``-echr 20`` 4754 4755ERST 4756 4757DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4758 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4759 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4760 "-incoming unix:socketpath\n" \ 4761 " prepare for incoming migration, listen on\n" \ 4762 " specified protocol and socket address\n" \ 4763 "-incoming fd:fd\n" \ 4764 "-incoming file:filename[,offset=offset]\n" \ 4765 "-incoming exec:cmdline\n" \ 4766 " accept incoming migration on given file descriptor\n" \ 4767 " or from given external command\n" \ 4768 "-incoming defer\n" \ 4769 " wait for the URI to be specified via migrate_incoming\n", 4770 QEMU_ARCH_ALL) 4771SRST 4772``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4773 \ 4774``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4775 Prepare for incoming migration, listen on a given tcp port. 4776 4777``-incoming unix:socketpath`` 4778 Prepare for incoming migration, listen on a given unix socket. 4779 4780``-incoming fd:fd`` 4781 Accept incoming migration from a given file descriptor. 4782 4783``-incoming file:filename[,offset=offset]`` 4784 Accept incoming migration from a given file starting at offset. 4785 offset allows the common size suffixes, or a 0x prefix, but not both. 4786 4787``-incoming exec:cmdline`` 4788 Accept incoming migration as an output from specified external 4789 command. 4790 4791``-incoming defer`` 4792 Wait for the URI to be specified via migrate\_incoming. The monitor 4793 can be used to change settings (such as migration parameters) prior 4794 to issuing the migrate\_incoming to allow the migration to begin. 4795ERST 4796 4797DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4798 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4799SRST 4800``-only-migratable`` 4801 Only allow migratable devices. Devices will not be allowed to enter 4802 an unmigratable state. 4803ERST 4804 4805DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4806 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4807SRST 4808``-nodefaults`` 4809 Don't create default devices. Normally, QEMU sets the default 4810 devices like serial port, parallel port, virtual console, monitor 4811 device, VGA adapter, floppy and CD-ROM drive and others. The 4812 ``-nodefaults`` option will disable all those default devices. 4813ERST 4814 4815#ifndef _WIN32 4816DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4817 "-runas user change to user id user just before starting the VM\n" \ 4818 " user can be numeric uid:gid instead\n", 4819 QEMU_ARCH_ALL) 4820#endif 4821SRST 4822``-runas user`` 4823 Immediately before starting guest execution, drop root privileges, 4824 switching to the specified user. 4825ERST 4826 4827DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4828 "-prom-env variable=value\n" 4829 " set OpenBIOS nvram variables\n", 4830 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4831SRST 4832``-prom-env variable=value`` 4833 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4834 4835 :: 4836 4837 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4838 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4839 4840 :: 4841 4842 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4843 -prom-env 'boot-device=hd:2,\yaboot' \ 4844 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4845ERST 4846DEF("semihosting", 0, QEMU_OPTION_semihosting, 4847 "-semihosting semihosting mode\n", 4848 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4849 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4850SRST 4851``-semihosting`` 4852 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4853 4854 .. warning:: 4855 Note that this allows guest direct access to the host filesystem, so 4856 should only be used with a trusted guest OS. 4857 4858 See the -semihosting-config option documentation for further 4859 information about the facilities this enables. 4860ERST 4861DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4862 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4863 " semihosting configuration\n", 4864QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4865QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4866SRST 4867``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4868 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4869 only). 4870 4871 .. warning:: 4872 Note that this allows guest direct access to the host filesystem, so 4873 should only be used with a trusted guest OS. 4874 4875 ``target=native|gdb|auto`` 4876 Defines where the semihosting calls will be addressed, to QEMU 4877 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4878 means ``gdb`` during debug sessions and ``native`` otherwise. 4879 4880 ``chardev=str1`` 4881 Send the output to a chardev backend output for native or auto 4882 output when not in gdb 4883 4884 ``userspace=on|off`` 4885 Allows code running in guest userspace to access the semihosting 4886 interface. The default is that only privileged guest code can 4887 make semihosting calls. Note that setting ``userspace=on`` should 4888 only be used if all guest code is trusted (for example, in 4889 bare-metal test case code). 4890 4891 ``arg=str1,arg=str2,...`` 4892 Allows the user to pass input arguments, and can be used 4893 multiple times to build up a list. The old-style 4894 ``-kernel``/``-append`` method of passing a command line is 4895 still supported for backward compatibility. If both the 4896 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4897 specified, the former is passed to semihosting as it always 4898 takes precedence. 4899ERST 4900DEF("old-param", 0, QEMU_OPTION_old_param, 4901 "-old-param old param mode\n", QEMU_ARCH_ARM) 4902SRST 4903``-old-param`` 4904 Old param mode (ARM only). 4905ERST 4906 4907DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4908 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4909 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4910 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4911 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4912 " by the kernel, but typically no longer used by modern\n" \ 4913 " C library implementations.\n" \ 4914 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4915 " to elevate privileges using set*uid|gid system calls.\n" \ 4916 " The value 'children' will deny set*uid|gid system calls for\n" \ 4917 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4918 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4919 " blocking *fork and execve\n" \ 4920 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4921 QEMU_ARCH_ALL) 4922SRST 4923``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4924 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4925 filtering and 'off' will disable it. The default is 'off'. 4926 4927 ``obsolete=string`` 4928 Enable Obsolete system calls 4929 4930 ``elevateprivileges=string`` 4931 Disable set\*uid\|gid system calls 4932 4933 ``spawn=string`` 4934 Disable \*fork and execve 4935 4936 ``resourcecontrol=string`` 4937 Disable process affinity and schedular priority 4938ERST 4939 4940DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4941 "-readconfig <file>\n" 4942 " read config file\n", QEMU_ARCH_ALL) 4943SRST 4944``-readconfig file`` 4945 Read device configuration from file. This approach is useful when 4946 you want to spawn QEMU process with many command line options but 4947 you don't want to exceed the command line character limit. 4948ERST 4949 4950DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4951 "-no-user-config\n" 4952 " do not load default user-provided config files at startup\n", 4953 QEMU_ARCH_ALL) 4954SRST 4955``-no-user-config`` 4956 The ``-no-user-config`` option makes QEMU not load any of the 4957 user-provided config files on sysconfdir. 4958ERST 4959 4960DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4961 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4962 " specify tracing options\n", 4963 QEMU_ARCH_ALL) 4964SRST 4965``-trace [[enable=]pattern][,events=file][,file=file]`` 4966 .. include:: ../qemu-option-trace.rst.inc 4967 4968ERST 4969DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4970 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4971 " load a plugin\n", 4972 QEMU_ARCH_ALL) 4973SRST 4974``-plugin file=file[,argname=argvalue]`` 4975 Load a plugin. 4976 4977 ``file=file`` 4978 Load the given plugin from a shared library file. 4979 4980 ``argname=argvalue`` 4981 Argument passed to the plugin. (Can be given multiple times.) 4982ERST 4983 4984HXCOMM Internal use 4985DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4986DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4987 4988#ifdef CONFIG_POSIX 4989DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4990 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4991 " Set miscellaneous QEMU process lifecycle options:\n" 4992 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4993 " chroot=dir chroot to dir just before starting the VM\n", 4994 QEMU_ARCH_ALL) 4995SRST 4996``-run-with [async-teardown=on|off][,chroot=dir]`` 4997 Set QEMU process lifecycle options. 4998 4999 ``async-teardown=on`` enables asynchronous teardown. A new process called 5000 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5001 space with the main QEMU process, using clone. It will wait for the 5002 main QEMU process to terminate completely, and then exit. This allows 5003 QEMU to terminate very quickly even if the guest was huge, leaving the 5004 teardown of the address space to the cleanup process. Since the cleanup 5005 process shares the same cgroups as the main QEMU process, accounting is 5006 performed correctly. This only works if the cleanup process is not 5007 forcefully killed with SIGKILL before the main QEMU process has 5008 terminated completely. 5009 5010 ``chroot=dir`` can be used for doing a chroot to the specified directory 5011 immediately before starting the guest execution. This is especially useful 5012 in combination with -runas. 5013ERST 5014#endif 5015 5016DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5017 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5018 " control error message format\n" 5019 " timestamp=on enables timestamps (default: off)\n" 5020 " guest-name=on enables guest name prefix but only if\n" 5021 " -name guest option is set (default: off)\n", 5022 QEMU_ARCH_ALL) 5023SRST 5024``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5025 Control error message format. 5026 5027 ``timestamp=on|off`` 5028 Prefix messages with a timestamp. Default is off. 5029 5030 ``guest-name=on|off`` 5031 Prefix messages with guest name but only if -name guest option is set 5032 otherwise the option is ignored. Default is off. 5033ERST 5034 5035DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5036 "-dump-vmstate <file>\n" 5037 " Output vmstate information in JSON format to file.\n" 5038 " Use the scripts/vmstate-static-checker.py file to\n" 5039 " check for possible regressions in migration code\n" 5040 " by comparing two such vmstate dumps.\n", 5041 QEMU_ARCH_ALL) 5042SRST 5043``-dump-vmstate file`` 5044 Dump json-encoded vmstate information for current machine type to 5045 file in file 5046ERST 5047 5048DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5049 "-enable-sync-profile\n" 5050 " enable synchronization profiling\n", 5051 QEMU_ARCH_ALL) 5052SRST 5053``-enable-sync-profile`` 5054 Enable synchronization profiling. 5055ERST 5056 5057#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5058DEF("perfmap", 0, QEMU_OPTION_perfmap, 5059 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5060 QEMU_ARCH_ALL) 5061SRST 5062``-perfmap`` 5063 Generate a map file for Linux perf tools that will allow basic profiling 5064 information to be broken down into basic blocks. 5065ERST 5066 5067DEF("jitdump", 0, QEMU_OPTION_jitdump, 5068 "-jitdump generate a jit-${pid}.dump file for perf\n", 5069 QEMU_ARCH_ALL) 5070SRST 5071``-jitdump`` 5072 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5073 names, line numbers and JITted code. 5074ERST 5075#endif 5076 5077DEFHEADING() 5078 5079DEFHEADING(Generic object creation:) 5080 5081DEF("object", HAS_ARG, QEMU_OPTION_object, 5082 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5083 " create a new object of type TYPENAME setting properties\n" 5084 " in the order they are specified. Note that the 'id'\n" 5085 " property must be set. These objects are placed in the\n" 5086 " '/objects' path.\n", 5087 QEMU_ARCH_ALL) 5088SRST 5089``-object typename[,prop1=value1,...]`` 5090 Create a new object of type typename setting properties in the order 5091 they are specified. Note that the 'id' property must be set. These 5092 objects are placed in the '/objects' path. 5093 5094 ``-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`` 5095 Creates a memory file backend object, which can be used to back 5096 the guest RAM with huge pages. 5097 5098 The ``id`` parameter is a unique ID that will be used to 5099 reference this memory region in other parameters, e.g. ``-numa``, 5100 ``-device nvdimm``, etc. 5101 5102 The ``size`` option provides the size of the memory region, and 5103 accepts common suffixes, e.g. ``500M``. 5104 5105 The ``mem-path`` provides the path to either a shared memory or 5106 huge page filesystem mount. 5107 5108 The ``share`` boolean option determines whether the memory 5109 region is marked as private to QEMU, or shared. The latter 5110 allows a co-operating external process to access the QEMU memory 5111 region. 5112 5113 The ``share`` is also required for pvrdma devices due to 5114 limitations in the RDMA API provided by Linux. 5115 5116 Setting share=on might affect the ability to configure NUMA 5117 bindings for the memory backend under some circumstances, see 5118 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5119 source tree for additional details. 5120 5121 Setting the ``discard-data`` boolean option to on indicates that 5122 file contents can be destroyed when QEMU exits, to avoid 5123 unnecessarily flushing data to the backing file. Note that 5124 ``discard-data`` is only an optimization, and QEMU might not 5125 discard file contents if it aborts unexpectedly or is terminated 5126 using SIGKILL. 5127 5128 The ``merge`` boolean option enables memory merge, also known as 5129 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5130 the pages for memory deduplication. 5131 5132 Setting the ``dump`` boolean option to off excludes the memory 5133 from core dumps. This feature is also known as MADV\_DONTDUMP. 5134 5135 The ``prealloc`` boolean option enables memory preallocation. 5136 5137 The ``host-nodes`` option binds the memory range to a list of 5138 NUMA host nodes. 5139 5140 The ``policy`` option sets the NUMA policy to one of the 5141 following values: 5142 5143 ``default`` 5144 default host policy 5145 5146 ``preferred`` 5147 prefer the given host node list for allocation 5148 5149 ``bind`` 5150 restrict memory allocation to the given host node list 5151 5152 ``interleave`` 5153 interleave memory allocations across the given host node 5154 list 5155 5156 The ``align`` option specifies the base address alignment when 5157 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5158 ``2M``. Some backend store specified by ``mem-path`` requires an 5159 alignment different than the default one used by QEMU, eg the 5160 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5161 such cases, users can specify the required alignment via this 5162 option. 5163 5164 The ``offset`` option specifies the offset into the target file 5165 that the region starts at. You can use this parameter to back 5166 multiple regions with a single file. 5167 5168 The ``pmem`` option specifies whether the backing file specified 5169 by ``mem-path`` is in host persistent memory that can be 5170 accessed using the SNIA NVM programming model (e.g. Intel 5171 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5172 operations to guarantee the persistence of its own writes to 5173 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5174 migration). Also, we will map the backend-file with MAP\_SYNC 5175 flag, which ensures the file metadata is in sync for 5176 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5177 requires support from both the host kernel (since Linux kernel 5178 4.15) and the filesystem of ``mem-path`` mounted with DAX 5179 option. 5180 5181 The ``readonly`` option specifies whether the backing file is opened 5182 read-only or read-write (default). 5183 5184 The ``rom`` option specifies whether to create Read Only Memory 5185 (ROM) that cannot be modified by the VM. Any write attempts to such 5186 ROM will be denied. Most use cases want proper RAM instead of ROM. 5187 However, selected use cases, like R/O NVDIMMs, can benefit from 5188 ROM. If set to ``on``, create ROM; if set to ``off``, create 5189 writable RAM; if set to ``auto`` (default), the value of the 5190 ``readonly`` option is used. This option is primarily helpful when 5191 we want to have writable RAM in configurations that would 5192 traditionally create ROM before the ``rom`` option was introduced: 5193 VM templating, where we want to open a file readonly 5194 (``readonly=on``) and mark the memory to be private for QEMU 5195 (``share=off``). For this use case, we need writable RAM instead 5196 of ROM, and want to also set ``rom=off``. 5197 5198 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave`` 5199 Creates a memory backend object, which can be used to back the 5200 guest RAM. Memory backend objects offer more control than the 5201 ``-m`` option that is traditionally used to define guest RAM. 5202 Please refer to ``memory-backend-file`` for a description of the 5203 options. 5204 5205 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size`` 5206 Creates an anonymous memory file backend object, which allows 5207 QEMU to share the memory with an external process (e.g. when 5208 using vhost-user). The memory is allocated with memfd and 5209 optional sealing. (Linux only) 5210 5211 The ``seal`` option creates a sealed-file, that will block 5212 further resizing the memory ('on' by default). 5213 5214 The ``hugetlb`` option specify the file to be created resides in 5215 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5216 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5217 the hugetlb page size on systems that support multiple hugetlb 5218 page sizes (it must be a power of 2 value supported by the 5219 system). 5220 5221 In some versions of Linux, the ``hugetlb`` option is 5222 incompatible with the ``seal`` option (requires at least Linux 5223 4.16). 5224 5225 Please refer to ``memory-backend-file`` for a description of the 5226 other options. 5227 5228 The ``share`` boolean option is on by default with memfd. 5229 5230 ``-object iommufd,id=id[,fd=fd]`` 5231 Creates an iommufd backend which allows control of DMA mapping 5232 through the ``/dev/iommu`` device. 5233 5234 The ``id`` parameter is a unique ID which frontends (such as 5235 vfio-pci of vdpa) will use to connect with the iommufd backend. 5236 5237 The ``fd`` parameter is an optional pre-opened file descriptor 5238 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5239 across all subsystems, bringing the benefit of centralized 5240 reference counting. 5241 5242 ``-object rng-builtin,id=id`` 5243 Creates a random number generator backend which obtains entropy 5244 from QEMU builtin functions. The ``id`` parameter is a unique ID 5245 that will be used to reference this entropy backend from the 5246 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5247 uses this RNG backend. 5248 5249 ``-object rng-random,id=id,filename=/dev/random`` 5250 Creates a random number generator backend which obtains entropy 5251 from a device on the host. The ``id`` parameter is a unique ID 5252 that will be used to reference this entropy backend from the 5253 ``virtio-rng`` device. The ``filename`` parameter specifies 5254 which file to obtain entropy from and if omitted defaults to 5255 ``/dev/urandom``. 5256 5257 ``-object rng-egd,id=id,chardev=chardevid`` 5258 Creates a random number generator backend which obtains entropy 5259 from an external daemon running on the host. The ``id`` 5260 parameter is a unique ID that will be used to reference this 5261 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5262 parameter is the unique ID of a character device backend that 5263 provides the connection to the RNG daemon. 5264 5265 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5266 Creates a TLS anonymous credentials object, which can be used to 5267 provide TLS support on network backends. The ``id`` parameter is 5268 a unique ID which network backends will use to access the 5269 credentials. The ``endpoint`` is either ``server`` or ``client`` 5270 depending on whether the QEMU network backend that uses the 5271 credentials will be acting as a client or as a server. If 5272 ``verify-peer`` is enabled (the default) then once the handshake 5273 is completed, the peer credentials will be verified, though this 5274 is a no-op for anonymous credentials. 5275 5276 The dir parameter tells QEMU where to find the credential files. 5277 For server endpoints, this directory may contain a file 5278 dh-params.pem providing diffie-hellman parameters to use for the 5279 TLS server. If the file is missing, QEMU will generate a set of 5280 DH parameters at startup. This is a computationally expensive 5281 operation that consumes random pool entropy, so it is 5282 recommended that a persistent set of parameters be generated 5283 upfront and saved. 5284 5285 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5286 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5287 can be used to provide TLS support on network backends. The 5288 ``id`` parameter is a unique ID which network backends will use 5289 to access the credentials. The ``endpoint`` is either ``server`` 5290 or ``client`` depending on whether the QEMU network backend that 5291 uses the credentials will be acting as a client or as a server. 5292 For clients only, ``username`` is the username which will be 5293 sent to the server. If omitted it defaults to "qemu". 5294 5295 The dir parameter tells QEMU where to find the keys file. It is 5296 called "dir/keys.psk" and contains "username:key" pairs. This 5297 file can most easily be created using the GnuTLS ``psktool`` 5298 program. 5299 5300 For server endpoints, dir may also contain a file dh-params.pem 5301 providing diffie-hellman parameters to use for the TLS server. 5302 If the file is missing, QEMU will generate a set of DH 5303 parameters at startup. This is a computationally expensive 5304 operation that consumes random pool entropy, so it is 5305 recommended that a persistent set of parameters be generated up 5306 front and saved. 5307 5308 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5309 Creates a TLS anonymous credentials object, which can be used to 5310 provide TLS support on network backends. The ``id`` parameter is 5311 a unique ID which network backends will use to access the 5312 credentials. The ``endpoint`` is either ``server`` or ``client`` 5313 depending on whether the QEMU network backend that uses the 5314 credentials will be acting as a client or as a server. If 5315 ``verify-peer`` is enabled (the default) then once the handshake 5316 is completed, the peer credentials will be verified. With x509 5317 certificates, this implies that the clients must be provided 5318 with valid client certificates too. 5319 5320 The dir parameter tells QEMU where to find the credential files. 5321 For server endpoints, this directory may contain a file 5322 dh-params.pem providing diffie-hellman parameters to use for the 5323 TLS server. If the file is missing, QEMU will generate a set of 5324 DH parameters at startup. This is a computationally expensive 5325 operation that consumes random pool entropy, so it is 5326 recommended that a persistent set of parameters be generated 5327 upfront and saved. 5328 5329 For x509 certificate credentials the directory will contain 5330 further files providing the x509 certificates. The certificates 5331 must be stored in PEM format, in filenames ca-cert.pem, 5332 ca-crl.pem (optional), server-cert.pem (only servers), 5333 server-key.pem (only servers), client-cert.pem (only clients), 5334 and client-key.pem (only clients). 5335 5336 For the server-key.pem and client-key.pem files which contain 5337 sensitive private keys, it is possible to use an encrypted 5338 version by providing the passwordid parameter. This provides the 5339 ID of a previously created ``secret`` object containing the 5340 password for decryption. 5341 5342 The priority parameter allows to override the global default 5343 priority used by gnutls. This can be useful if the system 5344 administrator needs to use a weaker set of crypto priorities for 5345 QEMU without potentially forcing the weakness onto all 5346 applications. Or conversely if one wants wants a stronger 5347 default for QEMU than for all other applications, they can do 5348 this through this parameter. Its format is a gnutls priority 5349 string as described at 5350 https://gnutls.org/manual/html_node/Priority-Strings.html. 5351 5352 ``-object tls-cipher-suites,id=id,priority=priority`` 5353 Creates a TLS cipher suites object, which can be used to control 5354 the TLS cipher/protocol algorithms that applications are permitted 5355 to use. 5356 5357 The ``id`` parameter is a unique ID which frontends will use to 5358 access the ordered list of permitted TLS cipher suites from the 5359 host. 5360 5361 The ``priority`` parameter allows to override the global default 5362 priority used by gnutls. This can be useful if the system 5363 administrator needs to use a weaker set of crypto priorities for 5364 QEMU without potentially forcing the weakness onto all 5365 applications. Or conversely if one wants wants a stronger 5366 default for QEMU than for all other applications, they can do 5367 this through this parameter. Its format is a gnutls priority 5368 string as described at 5369 https://gnutls.org/manual/html_node/Priority-Strings.html. 5370 5371 An example of use of this object is to control UEFI HTTPS Boot. 5372 The tls-cipher-suites object exposes the ordered list of permitted 5373 TLS cipher suites from the host side to the guest firmware, via 5374 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5375 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5376 guest-side TLS. 5377 5378 In the following example, the priority at which the host-side policy 5379 is retrieved is given by the ``priority`` property. 5380 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5381 refer to /etc/crypto-policies/back-ends/gnutls.config. 5382 5383 .. parsed-literal:: 5384 5385 # |qemu_system| \\ 5386 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5387 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5388 5389 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5390 Interval t can't be 0, this filter batches the packet delivery: 5391 all packets arriving in a given interval on netdev netdevid are 5392 delayed until the end of the interval. Interval is in 5393 microseconds. ``status`` is optional that indicate whether the 5394 netfilter is on (enabled) or off (disabled), the default status 5395 for netfilter will be 'on'. 5396 5397 queue all\|rx\|tx is an option that can be applied to any 5398 netfilter. 5399 5400 ``all``: the filter is attached both to the receive and the 5401 transmit queue of the netdev (default). 5402 5403 ``rx``: the filter is attached to the receive queue of the 5404 netdev, where it will receive packets sent to the netdev. 5405 5406 ``tx``: the filter is attached to the transmit queue of the 5407 netdev, where it will receive packets sent by the netdev. 5408 5409 position head\|tail\|id=<id> is an option to specify where the 5410 filter should be inserted in the filter list. It can be applied 5411 to any netfilter. 5412 5413 ``head``: the filter is inserted at the head of the filter list, 5414 before any existing filters. 5415 5416 ``tail``: the filter is inserted at the tail of the filter list, 5417 behind any existing filters (default). 5418 5419 ``id=<id>``: the filter is inserted before or behind the filter 5420 specified by <id>, see the insert option below. 5421 5422 insert behind\|before is an option to specify where to insert 5423 the new filter relative to the one specified with 5424 position=id=<id>. It can be applied to any netfilter. 5425 5426 ``before``: insert before the specified filter. 5427 5428 ``behind``: insert behind the specified filter (default). 5429 5430 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5431 filter-mirror on netdev netdevid,mirror net packet to 5432 chardevchardevid, if it has the vnet\_hdr\_support flag, 5433 filter-mirror will mirror packet with vnet\_hdr\_len. 5434 5435 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5436 filter-redirector on netdev netdevid,redirect filter's net 5437 packet to chardev chardevid,and redirect indev's packet to 5438 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5439 will redirect packet with vnet\_hdr\_len. Create a 5440 filter-redirector we need to differ outdev id from indev id, id 5441 can not be the same. we can just use indev or outdev, but at 5442 least one of indev or outdev need to be specified. 5443 5444 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5445 Filter-rewriter is a part of COLO project.It will rewrite tcp 5446 packet to secondary from primary to keep secondary tcp 5447 connection,and rewrite tcp packet to primary from secondary make 5448 tcp packet can be handled by client.if it has the 5449 vnet\_hdr\_support flag, we can parse packet with vnet header. 5450 5451 usage: colo secondary: -object 5452 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5453 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5454 filter-rewriter,id=rew0,netdev=hn0,queue=all 5455 5456 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5457 Dump the network traffic on netdev dev to the file specified by 5458 filename. At most len bytes (64k by default) per packet are 5459 stored. The file format is libpcap, so it can be analyzed with 5460 tools such as tcpdump or Wireshark. 5461 5462 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]`` 5463 Colo-compare gets packet from primary\_in chardevid and 5464 secondary\_in, then compare whether the payload of primary packet 5465 and secondary packet are the same. If same, it will output 5466 primary packet to out\_dev, else it will notify COLO-framework to do 5467 checkpoint and send primary packet to out\_dev. In order to 5468 improve efficiency, we need to put the task of comparison in 5469 another iothread. If it has the vnet\_hdr\_support flag, 5470 colo compare will send/recv packet with vnet\_hdr\_len. 5471 The compare\_timeout=@var{ms} determines the maximum time of the 5472 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5473 is to set the period of scanning expired primary node network packets. 5474 The max\_queue\_size=@var{size} is to set the max compare queue 5475 size depend on user environment. 5476 If user want to use Xen COLO, need to add the notify\_dev to 5477 notify Xen colo-frame to do checkpoint. 5478 5479 COLO-compare must be used with the help of filter-mirror, 5480 filter-redirector and filter-rewriter. 5481 5482 :: 5483 5484 KVM COLO 5485 5486 primary: 5487 -netdev tap,id=hn0,vhost=off 5488 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5489 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5490 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5491 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5492 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5493 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5494 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5495 -object iothread,id=iothread1 5496 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5497 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5498 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5499 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5500 5501 secondary: 5502 -netdev tap,id=hn0,vhost=off 5503 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5504 -chardev socket,id=red0,host=3.3.3.3,port=9003 5505 -chardev socket,id=red1,host=3.3.3.3,port=9004 5506 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5507 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5508 5509 5510 Xen COLO 5511 5512 primary: 5513 -netdev tap,id=hn0,vhost=off 5514 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5515 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5516 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5517 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5518 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5519 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5520 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5521 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5522 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5523 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5524 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5525 -object iothread,id=iothread1 5526 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=notify_way,iothread=iothread1 5527 5528 secondary: 5529 -netdev tap,id=hn0,vhost=off 5530 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5531 -chardev socket,id=red0,host=3.3.3.3,port=9003 5532 -chardev socket,id=red1,host=3.3.3.3,port=9004 5533 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5534 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5535 5536 If you want to know the detail of above command line, you can 5537 read the colo-compare git log. 5538 5539 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5540 Creates a cryptodev backend which executes crypto operations from 5541 the QEMU cipher APIs. The id parameter is a unique ID that will 5542 be used to reference this cryptodev backend from the 5543 ``virtio-crypto`` device. The queues parameter is optional, 5544 which specify the queue number of cryptodev backend, the default 5545 of queues is 1. 5546 5547 .. parsed-literal:: 5548 5549 # |qemu_system| \\ 5550 [...] \\ 5551 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5552 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5553 [...] 5554 5555 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5556 Creates a vhost-user cryptodev backend, backed by a chardev 5557 chardevid. The id parameter is a unique ID that will be used to 5558 reference this cryptodev backend from the ``virtio-crypto`` 5559 device. The chardev should be a unix domain socket backed one. 5560 The vhost-user uses a specifically defined protocol to pass 5561 vhost ioctl replacement messages to an application on the other 5562 end of the socket. The queues parameter is optional, which 5563 specify the queue number of cryptodev backend for multiqueue 5564 vhost-user, the default of queues is 1. 5565 5566 .. parsed-literal:: 5567 5568 # |qemu_system| \\ 5569 [...] \\ 5570 -chardev socket,id=chardev0,path=/path/to/socket \\ 5571 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5572 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5573 [...] 5574 5575 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5576 \ 5577 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5578 Defines a secret to store a password, encryption key, or some 5579 other sensitive data. The sensitive data can either be passed 5580 directly via the data parameter, or indirectly via the file 5581 parameter. Using the data parameter is insecure unless the 5582 sensitive data is encrypted. 5583 5584 The sensitive data can be provided in raw format (the default), 5585 or base64. When encoded as JSON, the raw format only supports 5586 valid UTF-8 characters, so base64 is recommended for sending 5587 binary data. QEMU will convert from which ever format is 5588 provided to the format it needs internally. eg, an RBD password 5589 can be provided in raw format, even though it will be base64 5590 encoded when passed onto the RBD sever. 5591 5592 For added protection, it is possible to encrypt the data 5593 associated with a secret using the AES-256-CBC cipher. Use of 5594 encryption is indicated by providing the keyid and iv 5595 parameters. The keyid parameter provides the ID of a previously 5596 defined secret that contains the AES-256 decryption key. This 5597 key should be 32-bytes long and be base64 encoded. The iv 5598 parameter provides the random initialization vector used for 5599 encryption of this particular secret and should be a base64 5600 encrypted string of the 16-byte IV. 5601 5602 The simplest (insecure) usage is to provide the secret inline 5603 5604 .. parsed-literal:: 5605 5606 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5607 5608 The simplest secure usage is to provide the secret via a file 5609 5610 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5611 secret,id=sec0,file=mypasswd.txt,format=raw 5612 5613 For greater security, AES-256-CBC should be used. To illustrate 5614 usage, consider the openssl command line tool which can encrypt 5615 the data. Note that when encrypting, the plaintext must be 5616 padded to the cipher block size (32 bytes) using the standard 5617 PKCS#5/6 compatible padding algorithm. 5618 5619 First a master key needs to be created in base64 encoding: 5620 5621 :: 5622 5623 # openssl rand -base64 32 > key.b64 5624 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5625 5626 Each secret to be encrypted needs to have a random 5627 initialization vector generated. These do not need to be kept 5628 secret 5629 5630 :: 5631 5632 # openssl rand -base64 16 > iv.b64 5633 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5634 5635 The secret to be defined can now be encrypted, in this case 5636 we're telling openssl to base64 encode the result, but it could 5637 be left as raw bytes if desired. 5638 5639 :: 5640 5641 # SECRET=$(printf "letmein" | 5642 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5643 5644 When launching QEMU, create a master secret pointing to 5645 ``key.b64`` and specify that to be used to decrypt the user 5646 password. Pass the contents of ``iv.b64`` to the second secret 5647 5648 .. parsed-literal:: 5649 5650 # |qemu_system| \\ 5651 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5652 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5653 data=$SECRET,iv=$(<iv.b64) 5654 5655 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file,kernel-hashes=on|off]`` 5656 Create a Secure Encrypted Virtualization (SEV) guest object, 5657 which can be used to provide the guest memory encryption support 5658 on AMD processors. 5659 5660 When memory encryption is enabled, one of the physical address 5661 bit (aka the C-bit) is utilized to mark if a memory page is 5662 protected. The ``cbitpos`` is used to provide the C-bit 5663 position. The C-bit position is Host family dependent hence user 5664 must provide this value. On EPYC, the value should be 47. 5665 5666 When memory encryption is enabled, we loose certain bits in 5667 physical address space. The ``reduced-phys-bits`` is used to 5668 provide the number of bits we loose in physical address space. 5669 Similar to C-bit, the value is Host family dependent. On EPYC, 5670 a guest will lose a maximum of 1 bit, so the value should be 1. 5671 5672 The ``sev-device`` provides the device file to use for 5673 communicating with the SEV firmware running inside AMD Secure 5674 Processor. The default device is '/dev/sev'. If hardware 5675 supports memory encryption then /dev/sev devices are created by 5676 CCP driver. 5677 5678 The ``policy`` provides the guest policy to be enforced by the 5679 SEV firmware and restrict what configuration and operational 5680 commands can be performed on this guest by the hypervisor. The 5681 policy should be provided by the guest owner and is bound to the 5682 guest and cannot be changed throughout the lifetime of the 5683 guest. The default is 0. 5684 5685 If guest ``policy`` allows sharing the key with another SEV 5686 guest then ``handle`` can be use to provide handle of the guest 5687 from which to share the key. 5688 5689 The ``dh-cert-file`` and ``session-file`` provides the guest 5690 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5691 and session parameters are used for establishing a cryptographic 5692 session with the guest owner to negotiate keys used for 5693 attestation. The file must be encoded in base64. 5694 5695 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5696 cmdline to a designated guest firmware page for measured Linux 5697 boot with -kernel. The default is off. (Since 6.2) 5698 5699 e.g to launch a SEV guest 5700 5701 .. parsed-literal:: 5702 5703 # |qemu_system_x86| \\ 5704 ...... \\ 5705 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5706 -machine ...,memory-encryption=sev0 \\ 5707 ..... 5708 5709 ``-object authz-simple,id=id,identity=string`` 5710 Create an authorization object that will control access to 5711 network services. 5712 5713 The ``identity`` parameter is identifies the user and its format 5714 depends on the network service that authorization object is 5715 associated with. For authorizing based on TLS x509 certificates, 5716 the identity must be the x509 distinguished name. Note that care 5717 must be taken to escape any commas in the distinguished name. 5718 5719 An example authorization object to validate a x509 distinguished 5720 name would look like: 5721 5722 .. parsed-literal:: 5723 5724 # |qemu_system| \\ 5725 ... \\ 5726 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5727 ... 5728 5729 Note the use of quotes due to the x509 distinguished name 5730 containing whitespace, and escaping of ','. 5731 5732 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5733 Create an authorization object that will control access to 5734 network services. 5735 5736 The ``filename`` parameter is the fully qualified path to a file 5737 containing the access control list rules in JSON format. 5738 5739 An example set of rules that match against SASL usernames might 5740 look like: 5741 5742 :: 5743 5744 { 5745 "rules": [ 5746 { "match": "fred", "policy": "allow", "format": "exact" }, 5747 { "match": "bob", "policy": "allow", "format": "exact" }, 5748 { "match": "danb", "policy": "deny", "format": "glob" }, 5749 { "match": "dan*", "policy": "allow", "format": "exact" }, 5750 ], 5751 "policy": "deny" 5752 } 5753 5754 When checking access the object will iterate over all the rules 5755 and the first rule to match will have its ``policy`` value 5756 returned as the result. If no rules match, then the default 5757 ``policy`` value is returned. 5758 5759 The rules can either be an exact string match, or they can use 5760 the simple UNIX glob pattern matching to allow wildcards to be 5761 used. 5762 5763 If ``refresh`` is set to true the file will be monitored and 5764 automatically reloaded whenever its content changes. 5765 5766 As with the ``authz-simple`` object, the format of the identity 5767 strings being matched depends on the network service, but is 5768 usually a TLS x509 distinguished name, or a SASL username. 5769 5770 An example authorization object to validate a SASL username 5771 would look like: 5772 5773 .. parsed-literal:: 5774 5775 # |qemu_system| \\ 5776 ... \\ 5777 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5778 ... 5779 5780 ``-object authz-pam,id=id,service=string`` 5781 Create an authorization object that will control access to 5782 network services. 5783 5784 The ``service`` parameter provides the name of a PAM service to 5785 use for authorization. It requires that a file 5786 ``/etc/pam.d/service`` exist to provide the configuration for 5787 the ``account`` subsystem. 5788 5789 An example authorization object to validate a TLS x509 5790 distinguished name would look like: 5791 5792 .. parsed-literal:: 5793 5794 # |qemu_system| \\ 5795 ... \\ 5796 -object authz-pam,id=auth0,service=qemu-vnc \\ 5797 ... 5798 5799 There would then be a corresponding config file for PAM at 5800 ``/etc/pam.d/qemu-vnc`` that contains: 5801 5802 :: 5803 5804 account requisite pam_listfile.so item=user sense=allow \ 5805 file=/etc/qemu/vnc.allow 5806 5807 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5808 of x509 distinguished names that are permitted access 5809 5810 :: 5811 5812 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5813 5814 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5815 Creates a dedicated event loop thread that devices can be 5816 assigned to. This is known as an IOThread. By default device 5817 emulation happens in vCPU threads or the main event loop thread. 5818 This can become a scalability bottleneck. IOThreads allow device 5819 emulation and I/O to run on other host CPUs. 5820 5821 The ``id`` parameter is a unique ID that will be used to 5822 reference this IOThread from ``-device ...,iothread=id``. 5823 Multiple devices can be assigned to an IOThread. Note that not 5824 all devices support an ``iothread`` parameter. 5825 5826 The ``query-iothreads`` QMP command lists IOThreads and reports 5827 their thread IDs so that the user can configure host CPU 5828 pinning/affinity. 5829 5830 IOThreads use an adaptive polling algorithm to reduce event loop 5831 latency. Instead of entering a blocking system call to monitor 5832 file descriptors and then pay the cost of being woken up when an 5833 event occurs, the polling algorithm spins waiting for events for 5834 a short time. The algorithm's default parameters are suitable 5835 for many cases but can be adjusted based on knowledge of the 5836 workload and/or host device latency. 5837 5838 The ``poll-max-ns`` parameter is the maximum number of 5839 nanoseconds to busy wait for events. Polling can be disabled by 5840 setting this value to 0. 5841 5842 The ``poll-grow`` parameter is the multiplier used to increase 5843 the polling time when the algorithm detects it is missing events 5844 due to not polling long enough. 5845 5846 The ``poll-shrink`` parameter is the divisor used to decrease 5847 the polling time when the algorithm detects it is spending too 5848 long polling without encountering events. 5849 5850 The ``aio-max-batch`` parameter is the maximum number of requests 5851 in a batch for the AIO engine, 0 means that the engine will use 5852 its default. 5853 5854 The IOThread parameters can be modified at run-time using the 5855 ``qom-set`` command (where ``iothread1`` is the IOThread's 5856 ``id``): 5857 5858 :: 5859 5860 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5861ERST 5862 5863 5864HXCOMM This is the last statement. Insert new options before this line! 5865 5866#undef DEF 5867#undef DEFHEADING 5868#undef ARCHHEADING 5869
