1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 41 QEMU_ARCH_ALL) 42SRST 43``-machine [type=]name[,prop=value[,...]]`` 44 Select the emulated machine by name. Use ``-machine help`` to list 45 available machines. 46 47 For architectures which aim to support live migration compatibility 48 across releases, each release will introduce a new versioned machine 49 type. For example, the 2.8.0 release introduced machine types 50 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 51 52 To allow live migration of guests from QEMU version 2.8.0, to QEMU 53 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 54 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 55 skip multiple intermediate releases when upgrading, new releases of 56 QEMU will support machine types from many previous versions. 57 58 Supported machine properties are: 59 60 ``accel=accels1[:accels2[:...]]`` 61 This is used to enable an accelerator. Depending on the target 62 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 63 By default, tcg is used. If there is more than one accelerator 64 specified, the next one is used if the previous one fails to 65 initialize. 66 67 ``vmport=on|off|auto`` 68 Enables emulation of VMWare IO port, for vmmouse etc. auto says 69 to select the value based on accel. For accel=xen the default is 70 off otherwise the default is on. 71 72 ``dump-guest-core=on|off`` 73 Include guest memory in a core dump. The default is on. 74 75 ``mem-merge=on|off`` 76 Enables or disables memory merge support. This feature, when 77 supported by the host, de-duplicates identical memory pages 78 among VMs instances (enabled by default). 79 80 ``aes-key-wrap=on|off`` 81 Enables or disables AES key wrapping support on s390-ccw hosts. 82 This feature controls whether AES wrapping keys will be created 83 to allow execution of AES cryptographic functions. The default 84 is on. 85 86 ``dea-key-wrap=on|off`` 87 Enables or disables DEA key wrapping support on s390-ccw hosts. 88 This feature controls whether DEA wrapping keys will be created 89 to allow execution of DEA cryptographic functions. The default 90 is on. 91 92 ``nvdimm=on|off`` 93 Enables or disables NVDIMM support. The default is off. 94 95 ``memory-encryption=`` 96 Memory encryption object to use. The default is none. 97 98 ``hmat=on|off`` 99 Enables or disables ACPI Heterogeneous Memory Attribute Table 100 (HMAT) support. The default is off. 101 102 ``memory-backend='id'`` 103 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 104 Allows to use a memory backend as main RAM. 105 106 For example: 107 :: 108 109 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 110 -machine memory-backend=pc.ram 111 -m 512M 112 113 Migration compatibility note: 114 115 * as backend id one shall use value of 'default-ram-id', advertised by 116 machine type (available via ``query-machines`` QMP command), if migration 117 to/from old QEMU (<5.0) is expected. 118 * for machine types 4.0 and older, user shall 119 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 120 if migration to/from old QEMU (<5.0) is expected. 121 122 For example: 123 :: 124 125 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 126 -machine memory-backend=pc.ram 127 -m 512M 128 129 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 130 Define a CXL Fixed Memory Window (CFMW). 131 132 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 133 134 They are regions of Host Physical Addresses (HPA) on a system which 135 may be interleaved across one or more CXL host bridges. The system 136 software will assign particular devices into these windows and 137 configure the downstream Host-managed Device Memory (HDM) decoders 138 in root ports, switch ports and devices appropriately to meet the 139 interleave requirements before enabling the memory devices. 140 141 ``targets.X=target`` provides the mapping to CXL host bridges 142 which may be identified by the id provided in the -device entry. 143 Multiple entries are needed to specify all the targets when 144 the fixed memory window represents interleaved memory. X is the 145 target index from 0. 146 147 ``size=size`` sets the size of the CFMW. This must be a multiple of 148 256MiB. The region will be aligned to 256MiB but the location is 149 platform and configuration dependent. 150 151 ``interleave-granularity=granularity`` sets the granularity of 152 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 153 4096KiB, 8192KiB and 16384KiB granularities supported. 154 155 Example: 156 157 :: 158 159 -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 160ERST 161 162DEF("M", HAS_ARG, QEMU_OPTION_M, 163 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 164 QEMU_ARCH_ALL) 165 166SRST 167``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 168 Define an SGX EPC section. 169ERST 170 171DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 172 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 173SRST 174``-cpu model`` 175 Select CPU model (``-cpu help`` for list and additional feature 176 selection) 177ERST 178 179DEF("accel", HAS_ARG, QEMU_OPTION_accel, 180 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 181 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 182 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 183 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 184 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 185 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 186 " split-wx=on|off (enable TCG split w^x mapping)\n" 187 " tb-size=n (TCG translation block cache size)\n" 188 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 189 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 190 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 191 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 192SRST 193``-accel name[,prop=value[,...]]`` 194 This is used to enable an accelerator. Depending on the target 195 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 196 default, tcg is used. If there is more than one accelerator 197 specified, the next one is used if the previous one fails to 198 initialize. 199 200 ``igd-passthru=on|off`` 201 When Xen is in use, this option controls whether Intel 202 integrated graphics devices can be passed through to the guest 203 (default=off) 204 205 ``kernel-irqchip=on|off|split`` 206 Controls KVM in-kernel irqchip support. The default is full 207 acceleration of the interrupt controllers. On x86, split irqchip 208 reduces the kernel attack surface, at a performance cost for 209 non-MSI interrupts. Disabling the in-kernel irqchip completely 210 is not recommended except for debugging purposes. 211 212 ``kvm-shadow-mem=size`` 213 Defines the size of the KVM shadow MMU. 214 215 ``one-insn-per-tb=on|off`` 216 Makes the TCG accelerator put only one guest instruction into 217 each translation block. This slows down emulation a lot, but 218 can be useful in some situations, such as when trying to analyse 219 the logs produced by the ``-d`` option. 220 221 ``split-wx=on|off`` 222 Controls the use of split w^x mapping for the TCG code generation 223 buffer. Some operating systems require this to be enabled, and in 224 such a case this will default on. On other operating systems, this 225 will default off, but one may enable this for testing or debugging. 226 227 ``tb-size=n`` 228 Controls the size (in MiB) of the TCG translation block cache. 229 230 ``thread=single|multi`` 231 Controls number of TCG threads. When the TCG is multi-threaded 232 there will be one thread per vCPU therefore taking advantage of 233 additional host cores. The default is to enable multi-threading 234 where both the back-end and front-ends support it and no 235 incompatible TCG features have been enabled (e.g. 236 icount/replay). 237 238 ``dirty-ring-size=n`` 239 When the KVM accelerator is used, it controls the size of the per-vCPU 240 dirty page ring buffer (number of entries for each vCPU). It should 241 be a value that is power of two, and it should be 1024 or bigger (but 242 still less than the maximum value that the kernel supports). 4096 243 could be a good initial value if you have no idea which is the best. 244 Set this value to 0 to disable the feature. By default, this feature 245 is disabled (dirty-ring-size=0). When enabled, KVM will instead 246 record dirty pages in a bitmap. 247 248 ``eager-split-size=n`` 249 KVM implements dirty page logging at the PAGE_SIZE granularity and 250 enabling dirty-logging on a huge-page requires breaking it into 251 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 252 lazily by default. There are performance benefits in doing huge-page 253 split eagerly, especially in situations where TLBI costs associated 254 with break-before-make sequences are considerable and also if guest 255 workloads are read intensive. The size here specifies how many pages 256 to break at a time and needs to be a valid block size which is 257 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 258 respectively. Be wary of specifying a higher size as it will have an 259 impact on the memory. By default, this feature is disabled 260 (eager-split-size=0). 261 262 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 263 Enables or disables notify VM exit support on x86 host and specify 264 the corresponding notify window to trigger the VM exit if enabled. 265 ``run`` option enables the feature. It does nothing and continue 266 if the exit happens. ``internal-error`` option enables the feature. 267 It raises a internal error. ``disable`` option doesn't enable the feature. 268 This feature can mitigate the CPU stuck issue due to event windows don't 269 open up for a specified of time (i.e. notify-window). 270 Default: notify-vmexit=run,notify-window=0. 271 272ERST 273 274DEF("smp", HAS_ARG, QEMU_OPTION_smp, 275 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 276 " [,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 277 " set the number of initial CPUs to 'n' [default=1]\n" 278 " maxcpus= maximum number of total CPUs, including\n" 279 " offline CPUs for hotplug, etc\n" 280 " drawers= number of drawers on the machine board\n" 281 " books= number of books in one drawer\n" 282 " sockets= number of sockets in one book\n" 283 " dies= number of dies in one socket\n" 284 " clusters= number of clusters in one die\n" 285 " cores= number of cores in one cluster\n" 286 " threads= number of threads in one core\n" 287 "Note: Different machines may have different subsets of the CPU topology\n" 288 " parameters supported, so the actual meaning of the supported parameters\n" 289 " will vary accordingly. For example, for a machine type that supports a\n" 290 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 291 " sequentially mean as below:\n" 292 " sockets means the number of sockets on the machine board\n" 293 " cores means the number of cores in one socket\n" 294 " threads means the number of threads in one core\n" 295 " For a particular machine type board, an expected CPU topology hierarchy\n" 296 " can be defined through the supported sub-option. Unsupported parameters\n" 297 " can also be provided in addition to the sub-option, but their values\n" 298 " must be set as 1 in the purpose of correct parsing.\n", 299 QEMU_ARCH_ALL) 300SRST 301``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 302 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 303 the machine type board. On boards supporting CPU hotplug, the optional 304 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 305 added at runtime. When both parameters are omitted, the maximum number 306 of CPUs will be calculated from the provided topology members and the 307 initial CPU count will match the maximum number. When only one of them 308 is given then the omitted one will be set to its counterpart's value. 309 Both parameters may be specified, but the maximum number of CPUs must 310 be equal to or greater than the initial CPU count. Product of the 311 CPU topology hierarchy must be equal to the maximum number of CPUs. 312 Both parameters are subject to an upper limit that is determined by 313 the specific machine type chosen. 314 315 To control reporting of CPU topology information, values of the topology 316 parameters can be specified. Machines may only support a subset of the 317 parameters and different machines may have different subsets supported 318 which vary depending on capacity of the corresponding CPU targets. So 319 for a particular machine type board, an expected topology hierarchy can 320 be defined through the supported sub-option. Unsupported parameters can 321 also be provided in addition to the sub-option, but their values must be 322 set as 1 in the purpose of correct parsing. 323 324 Either the initial CPU count, or at least one of the topology parameters 325 must be specified. The specified parameters must be greater than zero, 326 explicit configuration like "cpus=0" is not allowed. Values for any 327 omitted parameters will be computed from those which are given. 328 329 For example, the following sub-option defines a CPU topology hierarchy 330 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 331 core) for a machine that only supports sockets/cores/threads. 332 Some members of the option can be omitted but their values will be 333 automatically computed: 334 335 :: 336 337 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 338 339 The following sub-option defines a CPU topology hierarchy (2 sockets 340 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 341 per core) for PC machines which support sockets/dies/cores/threads. 342 Some members of the option can be omitted but their values will be 343 automatically computed: 344 345 :: 346 347 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 348 349 The following sub-option defines a CPU topology hierarchy (2 sockets 350 totally on the machine, 2 clusters per socket, 2 cores per cluster, 351 2 threads per core) for ARM virt machines which support sockets/clusters 352 /cores/threads. Some members of the option can be omitted but their values 353 will be automatically computed: 354 355 :: 356 357 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 358 359 Historically preference was given to the coarsest topology parameters 360 when computing missing values (ie sockets preferred over cores, which 361 were preferred over threads), however, this behaviour is considered 362 liable to change. Prior to 6.2 the preference was sockets over cores 363 over threads. Since 6.2 the preference is cores over sockets over threads. 364 365 For example, the following option defines a machine board with 2 sockets 366 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 367 368 :: 369 370 -smp 2 371 372 Note: The cluster topology will only be generated in ACPI and exposed 373 to guest if it's explicitly specified in -smp. 374ERST 375 376DEF("numa", HAS_ARG, QEMU_OPTION_numa, 377 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 378 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 379 "-numa dist,src=source,dst=destination,val=distance\n" 380 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 381 "-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" 382 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 383 QEMU_ARCH_ALL) 384SRST 385``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 386 \ 387``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 388 \ 389``-numa dist,src=source,dst=destination,val=distance`` 390 \ 391``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 392 \ 393``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 394 \ 395``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 396 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 397 distance from a source node to a destination node. Set the ACPI 398 Heterogeneous Memory Attributes for the given nodes. 399 400 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 401 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 402 contiguous range of CPU indexes (or a single VCPU if lastcpu is 403 omitted). A non-contiguous set of VCPUs can be represented by 404 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 405 omitted on all nodes, VCPUs are automatically split between them. 406 407 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 408 NUMA node: 409 410 :: 411 412 -numa node,cpus=0-2,cpus=5 413 414 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 415 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 416 assign CPU objects to a node using topology layout properties of 417 CPU. The set of properties is machine specific, and depends on used 418 machine type/'\ ``smp``\ ' options. It could be queried with 419 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 420 property specifies node to which CPU object will be assigned, it's 421 required for node to be declared with '\ ``node``\ ' option before 422 it's used with '\ ``cpu``\ ' option. 423 424 For example: 425 426 :: 427 428 -M pc \ 429 -smp 1,sockets=2,maxcpus=2 \ 430 -numa node,nodeid=0 -numa node,nodeid=1 \ 431 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 432 433 '\ ``memdev``\ ' option assigns RAM from a given memory backend 434 device to a node. It is recommended to use '\ ``memdev``\ ' option 435 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 436 option provides better performance and more control over the 437 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 438 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 439 440 For compatibility reasons, legacy '\ ``mem``\ ' option is 441 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 442 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 443 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 444 option, and vice versa. 445 446 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 447 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 448 for '\ ``-numa node``\ ' without memory specified was removed. 449 450 '\ ``initiator``\ ' is an additional option that points to an 451 initiator NUMA node that has best performance (the lowest latency or 452 largest bandwidth) to this NUMA node. Note that this option can be 453 set only when the machine property 'hmat' is set to 'on'. 454 455 Following example creates a machine with 2 NUMA nodes, node 0 has 456 CPU. node 1 has only memory, and its initiator is node 0. Note that 457 because node 0 has CPU, by default the initiator of node 0 is itself 458 and must be itself. 459 460 :: 461 462 -machine hmat=on \ 463 -m 2G,slots=2,maxmem=4G \ 464 -object memory-backend-ram,size=1G,id=m0 \ 465 -object memory-backend-ram,size=1G,id=m1 \ 466 -numa node,nodeid=0,memdev=m0 \ 467 -numa node,nodeid=1,memdev=m1,initiator=0 \ 468 -smp 2,sockets=2,maxcpus=2 \ 469 -numa cpu,node-id=0,socket-id=0 \ 470 -numa cpu,node-id=0,socket-id=1 471 472 source and destination are NUMA node IDs. distance is the NUMA 473 distance from source to destination. The distance from a node to 474 itself is always 10. If any pair of nodes is given a distance, then 475 all pairs must be given distances. Although, when distances are only 476 given in one direction for each pair of nodes, then the distances in 477 the opposite directions are assumed to be the same. If, however, an 478 asymmetrical pair of distances is given for even one node pair, then 479 all node pairs must be provided distance values for both directions, 480 even when they are symmetrical. When a node is unreachable from 481 another node, set the pair's distance to 255. 482 483 Note that the -``numa`` option doesn't allocate any of the specified 484 resources, it just assigns existing resources to NUMA nodes. This 485 means that one still has to use the ``-m``, ``-smp`` options to 486 allocate RAM and VCPUs respectively. 487 488 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 489 Information between initiator and target NUMA nodes in ACPI 490 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 491 create memory requests, usually it has one or more processors. 492 Target NUMA node contains addressable memory. 493 494 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 495 the memory hierarchy of the target NUMA node: if hierarchy is 496 'memory', the structure represents the memory performance; if 497 hierarchy is 'first-level\|second-level\|third-level', this 498 structure represents aggregated performance of memory side caches 499 for each domain. type of 'data-type' is type of data represented by 500 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 501 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 502 the target memory; if 'hierarchy' is 503 'first-level\|second-level\|third-level', 'data-type' is 504 'access\|read\|write' hit latency or 'access\|read\|write' hit 505 bandwidth of the target memory side cache. 506 507 lat is latency value in nanoseconds. bw is bandwidth value, the 508 possible value and units are NUM[M\|G\|T], mean that the bandwidth 509 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 510 used suffix). Note that if latency or bandwidth value is 0, means 511 the corresponding latency or bandwidth information is not provided. 512 513 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 514 belongs. size is the size of memory side cache in bytes. level is 515 the cache level described in this structure, note that the cache 516 level 0 should not be used with '\ ``hmat-cache``\ ' option. 517 associativity is the cache associativity, the possible value is 518 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 519 is the write policy. line is the cache Line size in bytes. 520 521 For example, the following options describe 2 NUMA nodes. Node 0 has 522 2 cpus and a ram, node 1 has only a ram. The processors in node 0 523 access memory in node 0 with access-latency 5 nanoseconds, 524 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 525 memory in NUMA node 1 with access-latency 10 nanoseconds, 526 access-bandwidth is 100 MB/s. And for memory side cache information, 527 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 528 policy is write-back, the cache Line size is 8 bytes: 529 530 :: 531 532 -machine hmat=on \ 533 -m 2G \ 534 -object memory-backend-ram,size=1G,id=m0 \ 535 -object memory-backend-ram,size=1G,id=m1 \ 536 -smp 2,sockets=2,maxcpus=2 \ 537 -numa node,nodeid=0,memdev=m0 \ 538 -numa node,nodeid=1,memdev=m1,initiator=0 \ 539 -numa cpu,node-id=0,socket-id=0 \ 540 -numa cpu,node-id=0,socket-id=1 \ 541 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 542 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 543 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 544 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 545 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 546 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 547ERST 548 549DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 550 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 551 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 552SRST 553``-add-fd fd=fd,set=set[,opaque=opaque]`` 554 Add a file descriptor to an fd set. Valid options are: 555 556 ``fd=fd`` 557 This option defines the file descriptor of which a duplicate is 558 added to fd set. The file descriptor cannot be stdin, stdout, or 559 stderr. 560 561 ``set=set`` 562 This option defines the ID of the fd set to add the file 563 descriptor to. 564 565 ``opaque=opaque`` 566 This option defines a free-form string that can be used to 567 describe fd. 568 569 You can open an image using pre-opened file descriptors from an fd 570 set: 571 572 .. parsed-literal:: 573 574 |qemu_system| \\ 575 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 576 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 577 -drive file=/dev/fdset/2,index=0,media=disk 578ERST 579 580DEF("set", HAS_ARG, QEMU_OPTION_set, 581 "-set group.id.arg=value\n" 582 " set <arg> parameter for item <id> of type <group>\n" 583 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 584SRST 585``-set group.id.arg=value`` 586 Set parameter arg for item id of type group 587ERST 588 589DEF("global", HAS_ARG, QEMU_OPTION_global, 590 "-global driver.property=value\n" 591 "-global driver=driver,property=property,value=value\n" 592 " set a global default for a driver property\n", 593 QEMU_ARCH_ALL) 594SRST 595``-global driver.prop=value`` 596 \ 597``-global driver=driver,property=property,value=value`` 598 Set default value of driver's property prop to value, e.g.: 599 600 .. parsed-literal:: 601 602 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 603 604 In particular, you can use this to set driver properties for devices 605 which are created automatically by the machine model. To create a 606 device which is not created automatically and set properties on it, 607 use -``device``. 608 609 -global driver.prop=value is shorthand for -global 610 driver=driver,property=prop,value=value. The longhand syntax works 611 even when driver contains a dot. 612ERST 613 614DEF("boot", HAS_ARG, QEMU_OPTION_boot, 615 "-boot [order=drives][,once=drives][,menu=on|off]\n" 616 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 617 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 618 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 619 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 620 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 621 QEMU_ARCH_ALL) 622SRST 623``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 624 Specify boot order drives as a string of drive letters. Valid drive 625 letters depend on the target architecture. The x86 PC uses: a, b 626 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 627 (Etherboot from network adapter 1-4), hard disk boot is the default. 628 To apply a particular boot order only on the first startup, specify 629 it via ``once``. Note that the ``order`` or ``once`` parameter 630 should not be used together with the ``bootindex`` property of 631 devices, since the firmware implementations normally do not support 632 both at the same time. 633 634 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 635 as firmware/BIOS supports them. The default is non-interactive boot. 636 637 A splash picture could be passed to bios, enabling user to show it 638 as logo, when option splash=sp\_name is given and menu=on, If 639 firmware/BIOS supports them. Currently Seabios for X86 system 640 support it. limitation: The splash file could be a jpeg file or a 641 BMP file in 24 BPP format(true color). The resolution should be 642 supported by the SVGA mode, so the recommended is 320x240, 640x480, 643 800x640. 644 645 A timeout could be passed to bios, guest will pause for rb\_timeout 646 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 647 not reboot, qemu passes '-1' to bios by default. Currently Seabios 648 for X86 system support it. 649 650 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 651 it. This only effects when boot priority is changed by bootindex 652 options. The default is non-strict boot. 653 654 .. parsed-literal:: 655 656 # try to boot from network first, then from hard disk 657 |qemu_system_x86| -boot order=nc 658 # boot from CD-ROM first, switch back to default order after reboot 659 |qemu_system_x86| -boot once=d 660 # boot with a splash picture for 5 seconds. 661 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 662 663 Note: The legacy format '-boot drives' is still supported but its 664 use is discouraged as it may be removed from future versions. 665ERST 666 667DEF("m", HAS_ARG, QEMU_OPTION_m, 668 "-m [size=]megs[,slots=n,maxmem=size]\n" 669 " configure guest RAM\n" 670 " size: initial amount of guest memory\n" 671 " slots: number of hotplug slots (default: none)\n" 672 " maxmem: maximum amount of guest memory (default: none)\n" 673 " Note: Some architectures might enforce a specific granularity\n", 674 QEMU_ARCH_ALL) 675SRST 676``-m [size=]megs[,slots=n,maxmem=size]`` 677 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 678 Optionally, a suffix of "M" or "G" can be used to signify a value in 679 megabytes or gigabytes respectively. Optional pair slots, maxmem 680 could be used to set amount of hotpluggable memory slots and maximum 681 amount of memory. Note that maxmem must be aligned to the page size. 682 683 For example, the following command-line sets the guest startup RAM 684 size to 1GB, creates 3 slots to hotplug additional memory and sets 685 the maximum memory the guest can reach to 4GB: 686 687 .. parsed-literal:: 688 689 |qemu_system| -m 1G,slots=3,maxmem=4G 690 691 If slots and maxmem are not specified, memory hotplug won't be 692 enabled and the guest startup RAM will never increase. 693ERST 694 695DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 696 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 697SRST 698``-mem-path path`` 699 Allocate guest RAM from a temporarily created file in path. 700ERST 701 702DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 703 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 704 QEMU_ARCH_ALL) 705SRST 706``-mem-prealloc`` 707 Preallocate memory when using -mem-path. 708ERST 709 710DEF("k", HAS_ARG, QEMU_OPTION_k, 711 "-k language use keyboard layout (for example 'fr' for French)\n", 712 QEMU_ARCH_ALL) 713SRST 714``-k language`` 715 Use keyboard layout language (for example ``fr`` for French). This 716 option is only needed where it is not easy to get raw PC keycodes 717 (e.g. on Macs, with some X11 servers or with a VNC or curses 718 display). You don't normally need to use it on PC/Linux or 719 PC/Windows hosts. 720 721 The available layouts are: 722 723 :: 724 725 ar de-ch es fo fr-ca hu ja mk no pt-br sv 726 da en-gb et fr fr-ch is lt nl pl ru th 727 de en-us fi fr-be hr it lv nl-be pt sl tr 728 729 The default is ``en-us``. 730ERST 731 732 733DEF("audio", HAS_ARG, QEMU_OPTION_audio, 734 "-audio [driver=]driver[,prop[=value][,...]]\n" 735 " specifies default audio backend when `audiodev` is not\n" 736 " used to create a machine or sound device;" 737 " options are the same as for -audiodev\n" 738 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 739 " specifies the audio backend and device to use;\n" 740 " apart from 'model', options are the same as for -audiodev.\n" 741 " use '-audio model=help' to show possible devices.\n", 742 QEMU_ARCH_ALL) 743SRST 744``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 745 If the ``model`` option is specified, ``-audio`` is a shortcut 746 for configuring both the guest audio hardware and the host audio 747 backend in one go. The guest hardware model can be set with 748 ``model=modelname``. Use ``model=help`` to list the available 749 device types. 750 751 The following two example do exactly the same, to show how ``-audio`` 752 can be used to shorten the command line length: 753 754 .. parsed-literal:: 755 756 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 757 |qemu_system| -audio pa,model=sb16 758 759 If the ``model`` option is not specified, ``-audio`` is used to 760 configure a default audio backend that will be used whenever the 761 ``audiodev`` property is not set on a device or machine. In 762 particular, ``-audio none`` ensures that no audio is produced even 763 for machines that have embedded sound hardware. 764 765 In both cases, the driver option is the same as with the corresponding 766 ``-audiodev`` option below. Use ``driver=help`` to list the available 767 drivers. 768 769ERST 770 771DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 772 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 773 " specifies the audio backend to use\n" 774 " Use ``-audiodev help`` to list the available drivers\n" 775 " id= identifier of the backend\n" 776 " timer-period= timer period in microseconds\n" 777 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 778 " in|out.fixed-settings= use fixed settings for host audio\n" 779 " in|out.frequency= frequency to use with fixed settings\n" 780 " in|out.channels= number of channels to use with fixed settings\n" 781 " in|out.format= sample format to use with fixed settings\n" 782 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 783 " in|out.voices= number of voices to use\n" 784 " in|out.buffer-length= length of buffer in microseconds\n" 785 "-audiodev none,id=id,[,prop[=value][,...]]\n" 786 " dummy driver that discards all output\n" 787#ifdef CONFIG_AUDIO_ALSA 788 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 789 " in|out.dev= name of the audio device to use\n" 790 " in|out.period-length= length of period in microseconds\n" 791 " in|out.try-poll= attempt to use poll mode\n" 792 " threshold= threshold (in microseconds) when playback starts\n" 793#endif 794#ifdef CONFIG_AUDIO_COREAUDIO 795 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 796 " in|out.buffer-count= number of buffers\n" 797#endif 798#ifdef CONFIG_AUDIO_DSOUND 799 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 800 " latency= add extra latency to playback in microseconds\n" 801#endif 802#ifdef CONFIG_AUDIO_OSS 803 "-audiodev oss,id=id[,prop[=value][,...]]\n" 804 " in|out.dev= path of the audio device to use\n" 805 " in|out.buffer-count= number of buffers\n" 806 " in|out.try-poll= attempt to use poll mode\n" 807 " try-mmap= try using memory mapped access\n" 808 " exclusive= open device in exclusive mode\n" 809 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 810#endif 811#ifdef CONFIG_AUDIO_PA 812 "-audiodev pa,id=id[,prop[=value][,...]]\n" 813 " server= PulseAudio server address\n" 814 " in|out.name= source/sink device name\n" 815 " in|out.latency= desired latency in microseconds\n" 816#endif 817#ifdef CONFIG_AUDIO_PIPEWIRE 818 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 819 " in|out.name= source/sink device name\n" 820 " in|out.stream-name= name of pipewire stream\n" 821 " in|out.latency= desired latency in microseconds\n" 822#endif 823#ifdef CONFIG_AUDIO_SDL 824 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 825 " in|out.buffer-count= number of buffers\n" 826#endif 827#ifdef CONFIG_AUDIO_SNDIO 828 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 829#endif 830#ifdef CONFIG_SPICE 831 "-audiodev spice,id=id[,prop[=value][,...]]\n" 832#endif 833#ifdef CONFIG_DBUS_DISPLAY 834 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 835#endif 836 "-audiodev wav,id=id[,prop[=value][,...]]\n" 837 " path= path of wav file to record\n", 838 QEMU_ARCH_ALL) 839SRST 840``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 841 Adds a new audio backend driver identified by id. There are global 842 and driver specific properties. Some values can be set differently 843 for input and output, they're marked with ``in|out.``. You can set 844 the input's property with ``in.prop`` and the output's property with 845 ``out.prop``. For example: 846 847 :: 848 849 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 850 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 851 852 NOTE: parameter validation is known to be incomplete, in many cases 853 specifying an invalid option causes QEMU to print an error message 854 and continue emulation without sound. 855 856 Valid global options are: 857 858 ``id=identifier`` 859 Identifies the audio backend. 860 861 ``timer-period=period`` 862 Sets the timer period used by the audio subsystem in 863 microseconds. Default is 10000 (10 ms). 864 865 ``in|out.mixing-engine=on|off`` 866 Use QEMU's mixing engine to mix all streams inside QEMU and 867 convert audio formats when not supported by the backend. When 868 off, fixed-settings must be off too. Note that disabling this 869 option means that the selected backend must support multiple 870 streams and the audio formats used by the virtual cards, 871 otherwise you'll get no sound. It's not recommended to disable 872 this option unless you want to use 5.1 or 7.1 audio, as mixing 873 engine only supports mono and stereo audio. Default is on. 874 875 ``in|out.fixed-settings=on|off`` 876 Use fixed settings for host audio. When off, it will change 877 based on how the guest opens the sound card. In this case you 878 must not specify frequency, channels or format. Default is on. 879 880 ``in|out.frequency=frequency`` 881 Specify the frequency to use when using fixed-settings. Default 882 is 44100Hz. 883 884 ``in|out.channels=channels`` 885 Specify the number of channels to use when using fixed-settings. 886 Default is 2 (stereo). 887 888 ``in|out.format=format`` 889 Specify the sample format to use when using fixed-settings. 890 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 891 ``u32``, ``f32``. Default is ``s16``. 892 893 ``in|out.voices=voices`` 894 Specify the number of voices to use. Default is 1. 895 896 ``in|out.buffer-length=usecs`` 897 Sets the size of the buffer in microseconds. 898 899``-audiodev none,id=id[,prop[=value][,...]]`` 900 Creates a dummy backend that discards all outputs. This backend has 901 no backend specific properties. 902 903``-audiodev alsa,id=id[,prop[=value][,...]]`` 904 Creates backend using the ALSA. This backend is only available on 905 Linux. 906 907 ALSA specific options are: 908 909 ``in|out.dev=device`` 910 Specify the ALSA device to use for input and/or output. Default 911 is ``default``. 912 913 ``in|out.period-length=usecs`` 914 Sets the period length in microseconds. 915 916 ``in|out.try-poll=on|off`` 917 Attempt to use poll mode with the device. Default is on. 918 919 ``threshold=threshold`` 920 Threshold (in microseconds) when playback starts. Default is 0. 921 922``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 923 Creates a backend using Apple's Core Audio. This backend is only 924 available on Mac OS and only supports playback. 925 926 Core Audio specific options are: 927 928 ``in|out.buffer-count=count`` 929 Sets the count of the buffers. 930 931``-audiodev dsound,id=id[,prop[=value][,...]]`` 932 Creates a backend using Microsoft's DirectSound. This backend is 933 only available on Windows and only supports playback. 934 935 DirectSound specific options are: 936 937 ``latency=usecs`` 938 Add extra usecs microseconds latency to playback. Default is 939 10000 (10 ms). 940 941``-audiodev oss,id=id[,prop[=value][,...]]`` 942 Creates a backend using OSS. This backend is available on most 943 Unix-like systems. 944 945 OSS specific options are: 946 947 ``in|out.dev=device`` 948 Specify the file name of the OSS device to use. Default is 949 ``/dev/dsp``. 950 951 ``in|out.buffer-count=count`` 952 Sets the count of the buffers. 953 954 ``in|out.try-poll=on|of`` 955 Attempt to use poll mode with the device. Default is on. 956 957 ``try-mmap=on|off`` 958 Try using memory mapped device access. Default is off. 959 960 ``exclusive=on|off`` 961 Open the device in exclusive mode (vmix won't work in this 962 case). Default is off. 963 964 ``dsp-policy=policy`` 965 Sets the timing policy (between 0 and 10, where smaller number 966 means smaller latency but higher CPU usage). Use -1 to use 967 buffer sizes specified by ``buffer`` and ``buffer-count``. This 968 option is ignored if you do not have OSS 4. Default is 5. 969 970``-audiodev pa,id=id[,prop[=value][,...]]`` 971 Creates a backend using PulseAudio. This backend is available on 972 most systems. 973 974 PulseAudio specific options are: 975 976 ``server=server`` 977 Sets the PulseAudio server to connect to. 978 979 ``in|out.name=sink`` 980 Use the specified source/sink for recording/playback. 981 982 ``in|out.latency=usecs`` 983 Desired latency in microseconds. The PulseAudio server will try 984 to honor this value but actual latencies may be lower or higher. 985 986``-audiodev pipewire,id=id[,prop[=value][,...]]`` 987 Creates a backend using PipeWire. This backend is available on 988 most systems. 989 990 PipeWire specific options are: 991 992 ``in|out.latency=usecs`` 993 Desired latency in microseconds. 994 995 ``in|out.name=sink`` 996 Use the specified source/sink for recording/playback. 997 998 ``in|out.stream-name`` 999 Specify the name of pipewire stream. 1000 1001``-audiodev sdl,id=id[,prop[=value][,...]]`` 1002 Creates a backend using SDL. This backend is available on most 1003 systems, but you should use your platform's native backend if 1004 possible. 1005 1006 SDL specific options are: 1007 1008 ``in|out.buffer-count=count`` 1009 Sets the count of the buffers. 1010 1011``-audiodev sndio,id=id[,prop[=value][,...]]`` 1012 Creates a backend using SNDIO. This backend is available on 1013 OpenBSD and most other Unix-like systems. 1014 1015 Sndio specific options are: 1016 1017 ``in|out.dev=device`` 1018 Specify the sndio device to use for input and/or output. Default 1019 is ``default``. 1020 1021 ``in|out.latency=usecs`` 1022 Sets the desired period length in microseconds. 1023 1024``-audiodev spice,id=id[,prop[=value][,...]]`` 1025 Creates a backend that sends audio through SPICE. This backend 1026 requires ``-spice`` and automatically selected in that case, so 1027 usually you can ignore this option. This backend has no backend 1028 specific properties. 1029 1030``-audiodev wav,id=id[,prop[=value][,...]]`` 1031 Creates a backend that writes audio to a WAV file. 1032 1033 Backend specific options are: 1034 1035 ``path=path`` 1036 Write recorded audio into the specified file. Default is 1037 ``qemu.wav``. 1038ERST 1039 1040DEF("device", HAS_ARG, QEMU_OPTION_device, 1041 "-device driver[,prop[=value][,...]]\n" 1042 " add device (based on driver)\n" 1043 " prop=value,... sets driver properties\n" 1044 " use '-device help' to print all possible drivers\n" 1045 " use '-device driver,help' to print all possible properties\n", 1046 QEMU_ARCH_ALL) 1047SRST 1048``-device driver[,prop[=value][,...]]`` 1049 Add device driver. prop=value sets driver properties. Valid 1050 properties depend on the driver. To get help on possible drivers and 1051 properties, use ``-device help`` and ``-device driver,help``. 1052 1053 Some drivers are: 1054 1055``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1056 Add an IPMI BMC. This is a simulation of a hardware management 1057 interface processor that normally sits on a system. It provides a 1058 watchdog and the ability to reset and power control the system. You 1059 need to connect this to an IPMI interface to make it useful 1060 1061 The IPMI slave address to use for the BMC. The default is 0x20. This 1062 address is the BMC's address on the I2C network of management 1063 controllers. If you don't know what this means, it is safe to ignore 1064 it. 1065 1066 ``id=id`` 1067 The BMC id for interfaces to use this device. 1068 1069 ``slave_addr=val`` 1070 Define slave address to use for the BMC. The default is 0x20. 1071 1072 ``sdrfile=file`` 1073 file containing raw Sensor Data Records (SDR) data. The default 1074 is none. 1075 1076 ``fruareasize=val`` 1077 size of a Field Replaceable Unit (FRU) area. The default is 1078 1024. 1079 1080 ``frudatafile=file`` 1081 file containing raw Field Replaceable Unit (FRU) inventory data. 1082 The default is none. 1083 1084 ``guid=uuid`` 1085 value for the GUID for the BMC, in standard UUID format. If this 1086 is set, get "Get GUID" command to the BMC will return it. 1087 Otherwise "Get GUID" will return an error. 1088 1089``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1090 Add a connection to an external IPMI BMC simulator. Instead of 1091 locally emulating the BMC like the above item, instead connect to an 1092 external entity that provides the IPMI services. 1093 1094 A connection is made to an external BMC simulator. If you do this, 1095 it is strongly recommended that you use the "reconnect=" chardev 1096 option to reconnect to the simulator if the connection is lost. Note 1097 that if this is not used carefully, it can be a security issue, as 1098 the interface has the ability to send resets, NMIs, and power off 1099 the VM. It's best if QEMU makes a connection to an external 1100 simulator running on a secure port on localhost, so neither the 1101 simulator nor QEMU is exposed to any outside network. 1102 1103 See the "lanserv/README.vm" file in the OpenIPMI library for more 1104 details on the external interface. 1105 1106``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1107 Add a KCS IPMI interface on the ISA bus. This also adds a 1108 corresponding ACPI and SMBIOS entries, if appropriate. 1109 1110 ``bmc=id`` 1111 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1112 above. 1113 1114 ``ioport=val`` 1115 Define the I/O address of the interface. The default is 0xca0 1116 for KCS. 1117 1118 ``irq=val`` 1119 Define the interrupt to use. The default is 5. To disable 1120 interrupts, set this to 0. 1121 1122``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1123 Like the KCS interface, but defines a BT interface. The default port 1124 is 0xe4 and the default interrupt is 5. 1125 1126``-device pci-ipmi-kcs,bmc=id`` 1127 Add a KCS IPMI interface on the PCI bus. 1128 1129 ``bmc=id`` 1130 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1131 1132``-device pci-ipmi-bt,bmc=id`` 1133 Like the KCS interface, but defines a BT interface on the PCI bus. 1134 1135``-device intel-iommu[,option=...]`` 1136 This is only supported by ``-machine q35``, which will enable Intel VT-d 1137 emulation within the guest. It supports below options: 1138 1139 ``intremap=on|off`` (default: auto) 1140 This enables interrupt remapping feature. It's required to enable 1141 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1142 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1143 The default value is "auto", which will be decided by the mode of 1144 kernel-irqchip. 1145 1146 ``caching-mode=on|off`` (default: off) 1147 This enables caching mode for the VT-d emulated device. When 1148 caching-mode is enabled, each guest DMA buffer mapping will generate an 1149 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1150 a synchronous way. It is required for ``-device vfio-pci`` to work 1151 with the VT-d device, because host assigned devices requires to setup 1152 the DMA mapping on the host before guest DMA starts. 1153 1154 ``device-iotlb=on|off`` (default: off) 1155 This enables device-iotlb capability for the emulated VT-d device. So 1156 far virtio/vhost should be the only real user for this parameter, 1157 paired with ats=on configured for the device. 1158 1159 ``aw-bits=39|48`` (default: 39) 1160 This decides the address width of IOVA address space. The address 1161 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1162 4-level IOMMU page tables. 1163 1164 Please also refer to the wiki page for general scenarios of VT-d 1165 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1166 1167ERST 1168 1169DEF("name", HAS_ARG, QEMU_OPTION_name, 1170 "-name string1[,process=string2][,debug-threads=on|off]\n" 1171 " set the name of the guest\n" 1172 " string1 sets the window title and string2 the process name\n" 1173 " When debug-threads is enabled, individual threads are given a separate name\n" 1174 " NOTE: The thread names are for debugging and not a stable API.\n", 1175 QEMU_ARCH_ALL) 1176SRST 1177``-name name`` 1178 Sets the name of the guest. This name will be displayed in the SDL 1179 window caption. The name will also be used for the VNC server. Also 1180 optionally set the top visible process name in Linux. Naming of 1181 individual threads can also be enabled on Linux to aid debugging. 1182ERST 1183 1184DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1185 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1186 " specify machine UUID\n", QEMU_ARCH_ALL) 1187SRST 1188``-uuid uuid`` 1189 Set system UUID. 1190ERST 1191 1192DEFHEADING() 1193 1194DEFHEADING(Block device options:) 1195 1196SRST 1197The QEMU block device handling options have a long history and 1198have gone through several iterations as the feature set and complexity 1199of the block layer have grown. Many online guides to QEMU often 1200reference older and deprecated options, which can lead to confusion. 1201 1202The most explicit way to describe disks is to use a combination of 1203``-device`` to specify the hardware device and ``-blockdev`` to 1204describe the backend. The device defines what the guest sees and the 1205backend describes how QEMU handles the data. It is the only guaranteed 1206stable interface for describing block devices and as such is 1207recommended for management tools and scripting. 1208 1209The ``-drive`` option combines the device and backend into a single 1210command line option which is a more human friendly. There is however no 1211interface stability guarantee although some older board models still 1212need updating to work with the modern blockdev forms. 1213 1214Older options like ``-hda`` are essentially macros which expand into 1215``-drive`` options for various drive interfaces. The original forms 1216bake in a lot of assumptions from the days when QEMU was emulating a 1217legacy PC, they are not recommended for modern configurations. 1218 1219ERST 1220 1221DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1222 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1223DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1224SRST 1225``-fda file`` 1226 \ 1227``-fdb file`` 1228 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1229 the System Emulation Users Guide). 1230ERST 1231 1232DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1233 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1234DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1235DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1236 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1237DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1238SRST 1239``-hda file`` 1240 \ 1241``-hdb file`` 1242 \ 1243``-hdc file`` 1244 \ 1245``-hdd file`` 1246 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1247 emulated machine (this is for example the IDE bus on most x86 machines, 1248 but it can also be SCSI, virtio or something else on other target 1249 architectures). See also the :ref:`disk images` chapter in the System 1250 Emulation Users Guide. 1251ERST 1252 1253DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1254 "-cdrom file use 'file' as CD-ROM image\n", 1255 QEMU_ARCH_ALL) 1256SRST 1257``-cdrom file`` 1258 Use file as CD-ROM image on the default bus of the emulated machine 1259 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1260 at the same time there). On systems that support it, you can use the 1261 host CD-ROM by using ``/dev/cdrom`` as filename. 1262ERST 1263 1264DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1265 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1266 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1267 " [,read-only=on|off][,auto-read-only=on|off]\n" 1268 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1269 " [,driver specific parameters...]\n" 1270 " configure a block backend\n", QEMU_ARCH_ALL) 1271SRST 1272``-blockdev option[,option[,option[,...]]]`` 1273 Define a new block driver node. Some of the options apply to all 1274 block drivers, other options are only accepted for a specific block 1275 driver. See below for a list of generic options and options for the 1276 most common block drivers. 1277 1278 Options that expect a reference to another node (e.g. ``file``) can 1279 be given in two ways. Either you specify the node name of an already 1280 existing node (file=node-name), or you define a new node inline, 1281 adding options for the referenced node after a dot 1282 (file.filename=path,file.aio=native). 1283 1284 A block driver node created with ``-blockdev`` can be used for a 1285 guest device by specifying its node name for the ``drive`` property 1286 in a ``-device`` argument that defines a block device. 1287 1288 ``Valid options for any block driver node:`` 1289 ``driver`` 1290 Specifies the block driver to use for the given node. 1291 1292 ``node-name`` 1293 This defines the name of the block driver node by which it 1294 will be referenced later. The name must be unique, i.e. it 1295 must not match the name of a different block driver node, or 1296 (if you use ``-drive`` as well) the ID of a drive. 1297 1298 If no node name is specified, it is automatically generated. 1299 The generated node name is not intended to be predictable 1300 and changes between QEMU invocations. For the top level, an 1301 explicit node name must be specified. 1302 1303 ``read-only`` 1304 Open the node read-only. Guest write attempts will fail. 1305 1306 Note that some block drivers support only read-only access, 1307 either generally or in certain configurations. In this case, 1308 the default value ``read-only=off`` does not work and the 1309 option must be specified explicitly. 1310 1311 ``auto-read-only`` 1312 If ``auto-read-only=on`` is set, QEMU may fall back to 1313 read-only usage even when ``read-only=off`` is requested, or 1314 even switch between modes as needed, e.g. depending on 1315 whether the image file is writable or whether a writing user 1316 is attached to the node. 1317 1318 ``force-share`` 1319 Override the image locking system of QEMU by forcing the 1320 node to utilize weaker shared access for permissions where 1321 it would normally request exclusive access. When there is 1322 the potential for multiple instances to have the same file 1323 open (whether this invocation of QEMU is the first or the 1324 second instance), both instances must permit shared access 1325 for the second instance to succeed at opening the file. 1326 1327 Enabling ``force-share=on`` requires ``read-only=on``. 1328 1329 ``cache.direct`` 1330 The host page cache can be avoided with ``cache.direct=on``. 1331 This will attempt to do disk IO directly to the guest's 1332 memory. QEMU may still perform an internal copy of the data. 1333 1334 ``cache.no-flush`` 1335 In case you don't care about data integrity over host 1336 failures, you can use ``cache.no-flush=on``. This option 1337 tells QEMU that it never needs to write any data to the disk 1338 but can instead keep things in cache. If anything goes 1339 wrong, like your host losing power, the disk storage getting 1340 disconnected accidentally, etc. your image will most 1341 probably be rendered unusable. 1342 1343 ``discard=discard`` 1344 discard is one of "ignore" (or "off") or "unmap" (or "on") 1345 and controls whether ``discard`` (also known as ``trim`` or 1346 ``unmap``) requests are ignored or passed to the filesystem. 1347 Some machine types may not support discard requests. 1348 1349 ``detect-zeroes=detect-zeroes`` 1350 detect-zeroes is "off", "on" or "unmap" and enables the 1351 automatic conversion of plain zero writes by the OS to 1352 driver specific optimized zero write commands. You may even 1353 choose "unmap" if discard is set to "unmap" to allow a zero 1354 write to be converted to an ``unmap`` operation. 1355 1356 ``Driver-specific options for file`` 1357 This is the protocol-level block driver for accessing regular 1358 files. 1359 1360 ``filename`` 1361 The path to the image file in the local filesystem 1362 1363 ``aio`` 1364 Specifies the AIO backend (threads/native/io_uring, 1365 default: threads) 1366 1367 ``locking`` 1368 Specifies whether the image file is protected with Linux OFD 1369 / POSIX locks. The default is to use the Linux Open File 1370 Descriptor API if available, otherwise no lock is applied. 1371 (auto/on/off, default: auto) 1372 1373 Example: 1374 1375 :: 1376 1377 -blockdev driver=file,node-name=disk,filename=disk.img 1378 1379 ``Driver-specific options for raw`` 1380 This is the image format block driver for raw images. It is 1381 usually stacked on top of a protocol level block driver such as 1382 ``file``. 1383 1384 ``file`` 1385 Reference to or definition of the data source block driver 1386 node (e.g. a ``file`` driver node) 1387 1388 Example 1: 1389 1390 :: 1391 1392 -blockdev driver=file,node-name=disk_file,filename=disk.img 1393 -blockdev driver=raw,node-name=disk,file=disk_file 1394 1395 Example 2: 1396 1397 :: 1398 1399 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1400 1401 ``Driver-specific options for qcow2`` 1402 This is the image format block driver for qcow2 images. It is 1403 usually stacked on top of a protocol level block driver such as 1404 ``file``. 1405 1406 ``file`` 1407 Reference to or definition of the data source block driver 1408 node (e.g. a ``file`` driver node) 1409 1410 ``backing`` 1411 Reference to or definition of the backing file block device 1412 (default is taken from the image file). It is allowed to 1413 pass ``null`` here in order to disable the default backing 1414 file. 1415 1416 ``lazy-refcounts`` 1417 Whether to enable the lazy refcounts feature (on/off; 1418 default is taken from the image file) 1419 1420 ``cache-size`` 1421 The maximum total size of the L2 table and refcount block 1422 caches in bytes (default: the sum of l2-cache-size and 1423 refcount-cache-size) 1424 1425 ``l2-cache-size`` 1426 The maximum size of the L2 table cache in bytes (default: if 1427 cache-size is not specified - 32M on Linux platforms, and 8M 1428 on non-Linux platforms; otherwise, as large as possible 1429 within the cache-size, while permitting the requested or the 1430 minimal refcount cache size) 1431 1432 ``refcount-cache-size`` 1433 The maximum size of the refcount block cache in bytes 1434 (default: 4 times the cluster size; or if cache-size is 1435 specified, the part of it which is not used for the L2 1436 cache) 1437 1438 ``cache-clean-interval`` 1439 Clean unused entries in the L2 and refcount caches. The 1440 interval is in seconds. The default value is 600 on 1441 supporting platforms, and 0 on other platforms. Setting it 1442 to 0 disables this feature. 1443 1444 ``pass-discard-request`` 1445 Whether discard requests to the qcow2 device should be 1446 forwarded to the data source (on/off; default: on if 1447 discard=unmap is specified, off otherwise) 1448 1449 ``pass-discard-snapshot`` 1450 Whether discard requests for the data source should be 1451 issued when a snapshot operation (e.g. deleting a snapshot) 1452 frees clusters in the qcow2 file (on/off; default: on) 1453 1454 ``pass-discard-other`` 1455 Whether discard requests for the data source should be 1456 issued on other occasions where a cluster gets freed 1457 (on/off; default: off) 1458 1459 ``discard-no-unref`` 1460 When enabled, data clusters will remain preallocated when they are 1461 no longer used, e.g. because they are discarded or converted to 1462 zero clusters. As usual, whether the old data is discarded or kept 1463 on the protocol level (i.e. in the image file) depends on the 1464 setting of the pass-discard-request option. Keeping the clusters 1465 preallocated prevents qcow2 fragmentation that would otherwise be 1466 caused by freeing and re-allocating them later. Besides potential 1467 performance degradation, such fragmentation can lead to increased 1468 allocation of clusters past the end of the image file, 1469 resulting in image files whose file length can grow much larger 1470 than their guest disk size would suggest. 1471 If image file length is of concern (e.g. when storing qcow2 1472 images directly on block devices), you should consider enabling 1473 this option. 1474 1475 ``overlap-check`` 1476 Which overlap checks to perform for writes to the image 1477 (none/constant/cached/all; default: cached). For details or 1478 finer granularity control refer to the QAPI documentation of 1479 ``blockdev-add``. 1480 1481 Example 1: 1482 1483 :: 1484 1485 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1486 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1487 1488 Example 2: 1489 1490 :: 1491 1492 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1493 1494 ``Driver-specific options for other drivers`` 1495 Please refer to the QAPI documentation of the ``blockdev-add`` 1496 QMP command. 1497ERST 1498 1499DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1500 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1501 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1502 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1503 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1504 " [,aio=threads|native|io_uring]\n" 1505 " [,readonly=on|off][,copy-on-read=on|off]\n" 1506 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1507 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1508 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1509 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1510 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1511 " [[,iops_size=is]]\n" 1512 " [[,group=g]]\n" 1513 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1514SRST 1515``-drive option[,option[,option[,...]]]`` 1516 Define a new drive. This includes creating a block driver node (the 1517 backend) as well as a guest device, and is mostly a shortcut for 1518 defining the corresponding ``-blockdev`` and ``-device`` options. 1519 1520 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1521 In addition, it knows the following options: 1522 1523 ``file=file`` 1524 This option defines which disk image (see the :ref:`disk images` 1525 chapter in the System Emulation Users Guide) to use with this drive. 1526 If the filename contains comma, you must double it (for instance, 1527 "file=my,,file" to use file "my,file"). 1528 1529 Special files such as iSCSI devices can be specified using 1530 protocol specific URLs. See the section for "Device URL Syntax" 1531 for more information. 1532 1533 ``if=interface`` 1534 This option defines on which type on interface the drive is 1535 connected. Available types are: ide, scsi, sd, mtd, floppy, 1536 pflash, virtio, none. 1537 1538 ``bus=bus,unit=unit`` 1539 These options define where is connected the drive by defining 1540 the bus number and the unit id. 1541 1542 ``index=index`` 1543 This option defines where the drive is connected by using an 1544 index in the list of available connectors of a given interface 1545 type. 1546 1547 ``media=media`` 1548 This option defines the type of the media: disk or cdrom. 1549 1550 ``snapshot=snapshot`` 1551 snapshot is "on" or "off" and controls snapshot mode for the 1552 given drive (see ``-snapshot``). 1553 1554 ``cache=cache`` 1555 cache is "none", "writeback", "unsafe", "directsync" or 1556 "writethrough" and controls how the host cache is used to access 1557 block data. This is a shortcut that sets the ``cache.direct`` 1558 and ``cache.no-flush`` options (as in ``-blockdev``), and 1559 additionally ``cache.writeback``, which provides a default for 1560 the ``write-cache`` option of block guest devices (as in 1561 ``-device``). The modes correspond to the following settings: 1562 1563 ============= =============== ============ ============== 1564 \ cache.writeback cache.direct cache.no-flush 1565 ============= =============== ============ ============== 1566 writeback on off off 1567 none on on off 1568 writethrough off off off 1569 directsync off on off 1570 unsafe on off on 1571 ============= =============== ============ ============== 1572 1573 The default mode is ``cache=writeback``. 1574 1575 ``aio=aio`` 1576 aio is "threads", "native", or "io_uring" and selects between pthread 1577 based disk I/O, native Linux AIO, or Linux io_uring API. 1578 1579 ``format=format`` 1580 Specify which disk format will be used rather than detecting the 1581 format. Can be used to specify format=raw to avoid interpreting 1582 an untrusted format header. 1583 1584 ``werror=action,rerror=action`` 1585 Specify which action to take on write and read errors. Valid 1586 actions are: "ignore" (ignore the error and try to continue), 1587 "stop" (pause QEMU), "report" (report the error to the guest), 1588 "enospc" (pause QEMU only if the host disk is full; report the 1589 error to the guest otherwise). The default setting is 1590 ``werror=enospc`` and ``rerror=report``. 1591 1592 ``copy-on-read=copy-on-read`` 1593 copy-on-read is "on" or "off" and enables whether to copy read 1594 backing file sectors into the image file. 1595 1596 ``bps=b,bps_rd=r,bps_wr=w`` 1597 Specify bandwidth throttling limits in bytes per second, either 1598 for all request types or for reads or writes only. Small values 1599 can lead to timeouts or hangs inside the guest. A safe minimum 1600 for disks is 2 MB/s. 1601 1602 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1603 Specify bursts in bytes per second, either for all request types 1604 or for reads or writes only. Bursts allow the guest I/O to spike 1605 above the limit temporarily. 1606 1607 ``iops=i,iops_rd=r,iops_wr=w`` 1608 Specify request rate limits in requests per second, either for 1609 all request types or for reads or writes only. 1610 1611 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1612 Specify bursts in requests per second, either for all request 1613 types or for reads or writes only. Bursts allow the guest I/O to 1614 spike above the limit temporarily. 1615 1616 ``iops_size=is`` 1617 Let every is bytes of a request count as a new request for iops 1618 throttling purposes. Use this option to prevent guests from 1619 circumventing iops limits by sending fewer but larger requests. 1620 1621 ``group=g`` 1622 Join a throttling quota group with given name g. All drives that 1623 are members of the same group are accounted for together. Use 1624 this option to prevent guests from circumventing throttling 1625 limits by using many small disks instead of a single larger 1626 disk. 1627 1628 By default, the ``cache.writeback=on`` mode is used. It will report 1629 data writes as completed as soon as the data is present in the host 1630 page cache. This is safe as long as your guest OS makes sure to 1631 correctly flush disk caches where needed. If your guest OS does not 1632 handle volatile disk write caches correctly and your host crashes or 1633 loses power, then the guest may experience data corruption. 1634 1635 For such guests, you should consider using ``cache.writeback=off``. 1636 This means that the host page cache will be used to read and write 1637 data, but write notification will be sent to the guest only after 1638 QEMU has made sure to flush each write to the disk. Be aware that 1639 this has a major impact on performance. 1640 1641 When using the ``-snapshot`` option, unsafe caching is always used. 1642 1643 Copy-on-read avoids accessing the same backing file sectors 1644 repeatedly and is useful when the backing file is over a slow 1645 network. By default copy-on-read is off. 1646 1647 Instead of ``-cdrom`` you can use: 1648 1649 .. parsed-literal:: 1650 1651 |qemu_system| -drive file=file,index=2,media=cdrom 1652 1653 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1654 1655 .. parsed-literal:: 1656 1657 |qemu_system| -drive file=file,index=0,media=disk 1658 |qemu_system| -drive file=file,index=1,media=disk 1659 |qemu_system| -drive file=file,index=2,media=disk 1660 |qemu_system| -drive file=file,index=3,media=disk 1661 1662 You can open an image using pre-opened file descriptors from an fd 1663 set: 1664 1665 .. parsed-literal:: 1666 1667 |qemu_system| \\ 1668 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1669 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1670 -drive file=/dev/fdset/2,index=0,media=disk 1671 1672 You can connect a CDROM to the slave of ide0: 1673 1674 .. parsed-literal:: 1675 1676 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1677 1678 If you don't specify the "file=" argument, you define an empty 1679 drive: 1680 1681 .. parsed-literal:: 1682 1683 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1684 1685 Instead of ``-fda``, ``-fdb``, you can use: 1686 1687 .. parsed-literal:: 1688 1689 |qemu_system_x86| -drive file=file,index=0,if=floppy 1690 |qemu_system_x86| -drive file=file,index=1,if=floppy 1691 1692 By default, interface is "ide" and index is automatically 1693 incremented: 1694 1695 .. parsed-literal:: 1696 1697 |qemu_system_x86| -drive file=a -drive file=b 1698 1699 is interpreted like: 1700 1701 .. parsed-literal:: 1702 1703 |qemu_system_x86| -hda a -hdb b 1704ERST 1705 1706DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1707 "-mtdblock file use 'file' as on-board Flash memory image\n", 1708 QEMU_ARCH_ALL) 1709SRST 1710``-mtdblock file`` 1711 Use file as on-board Flash memory image. 1712ERST 1713 1714DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1715 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1716SRST 1717``-sd file`` 1718 Use file as SecureDigital card image. 1719ERST 1720 1721DEF("snapshot", 0, QEMU_OPTION_snapshot, 1722 "-snapshot write to temporary files instead of disk image files\n", 1723 QEMU_ARCH_ALL) 1724SRST 1725``-snapshot`` 1726 Write to temporary files instead of disk image files. In this case, 1727 the raw disk image you use is not written back. You can however 1728 force the write back by pressing C-a s (see the :ref:`disk images` 1729 chapter in the System Emulation Users Guide). 1730 1731 .. warning:: 1732 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1733 to manually create snapshot images to attach to your blockdev). 1734 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1735 can use the 'snapshot' property on your drive declarations 1736 instead of this global option. 1737 1738ERST 1739 1740DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1741 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1742 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1743 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1744 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1745 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1746 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1747 " [[,throttling.iops-size=is]]\n" 1748 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1749 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1750 "-fsdev synth,id=id\n", 1751 QEMU_ARCH_ALL) 1752 1753SRST 1754``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1755 \ 1756``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1757 \ 1758``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1759 \ 1760``-fsdev synth,id=id[,readonly=on]`` 1761 Define a new file system device. Valid options are: 1762 1763 ``local`` 1764 Accesses to the filesystem are done by QEMU. 1765 1766 ``proxy`` 1767 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1768 option is deprecated (since QEMU 8.1) and will be removed in a future 1769 version of QEMU. Use ``local`` instead. 1770 1771 ``synth`` 1772 Synthetic filesystem, only used by QTests. 1773 1774 ``id=id`` 1775 Specifies identifier for this device. 1776 1777 ``path=path`` 1778 Specifies the export path for the file system device. Files 1779 under this path will be available to the 9p client on the guest. 1780 1781 ``security_model=security_model`` 1782 Specifies the security model to be used for this export path. 1783 Supported security models are "passthrough", "mapped-xattr", 1784 "mapped-file" and "none". In "passthrough" security model, files 1785 are stored using the same credentials as they are created on the 1786 guest. This requires QEMU to run as root. In "mapped-xattr" 1787 security model, some of the file attributes like uid, gid, mode 1788 bits and link target are stored as file attributes. For 1789 "mapped-file" these attributes are stored in the hidden 1790 .virtfs\_metadata directory. Directories exported by this 1791 security model cannot interact with other unix tools. "none" 1792 security model is same as passthrough except the sever won't 1793 report failures if it fails to set file attributes like 1794 ownership. Security model is mandatory only for local fsdriver. 1795 Other fsdrivers (like proxy) don't take security model as a 1796 parameter. 1797 1798 ``writeout=writeout`` 1799 This is an optional argument. The only supported value is 1800 "immediate". This means that host page cache will be used to 1801 read and write data but write notification will be sent to the 1802 guest only when the data has been reported as written by the 1803 storage subsystem. 1804 1805 ``readonly=on`` 1806 Enables exporting 9p share as a readonly mount for guests. By 1807 default read-write access is given. 1808 1809 ``socket=socket`` 1810 Enables proxy filesystem driver to use passed socket file for 1811 communicating with virtfs-proxy-helper(1). 1812 1813 ``sock_fd=sock_fd`` 1814 Enables proxy filesystem driver to use passed socket descriptor 1815 for communicating with virtfs-proxy-helper(1). Usually a helper 1816 like libvirt will create socketpair and pass one of the fds as 1817 sock\_fd. 1818 1819 ``fmode=fmode`` 1820 Specifies the default mode for newly created files on the host. 1821 Works only with security models "mapped-xattr" and 1822 "mapped-file". 1823 1824 ``dmode=dmode`` 1825 Specifies the default mode for newly created directories on the 1826 host. Works only with security models "mapped-xattr" and 1827 "mapped-file". 1828 1829 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1830 Specify bandwidth throttling limits in bytes per second, either 1831 for all request types or for reads or writes only. 1832 1833 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1834 Specify bursts in bytes per second, either for all request types 1835 or for reads or writes only. Bursts allow the guest I/O to spike 1836 above the limit temporarily. 1837 1838 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1839 Specify request rate limits in requests per second, either for 1840 all request types or for reads or writes only. 1841 1842 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1843 Specify bursts in requests per second, either for all request 1844 types or for reads or writes only. Bursts allow the guest I/O to 1845 spike above the limit temporarily. 1846 1847 ``throttling.iops-size=is`` 1848 Let every is bytes of a request count as a new request for iops 1849 throttling purposes. 1850 1851 -fsdev option is used along with -device driver "virtio-9p-...". 1852 1853``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1854 Options for virtio-9p-... driver are: 1855 1856 ``type`` 1857 Specifies the variant to be used. Supported values are "pci", 1858 "ccw" or "device", depending on the machine type. 1859 1860 ``fsdev=id`` 1861 Specifies the id value specified along with -fsdev option. 1862 1863 ``mount_tag=mount_tag`` 1864 Specifies the tag name to be used by the guest to mount this 1865 export point. 1866ERST 1867 1868DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1869 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1870 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1871 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1872 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1873 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1874 QEMU_ARCH_ALL) 1875 1876SRST 1877``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1878 \ 1879``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1880 \ 1881``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1882 \ 1883``-virtfs synth,mount_tag=mount_tag`` 1884 Define a new virtual filesystem device and expose it to the guest using 1885 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1886 directory on host is made directly accessible by guest as a pass-through 1887 file system by using the 9P network protocol for communication between 1888 host and guests, if desired even accessible, shared by several guests 1889 simultaneously. 1890 1891 Note that ``-virtfs`` is actually just a convenience shortcut for its 1892 generalized form ``-fsdev -device virtio-9p-pci``. 1893 1894 The general form of pass-through file system options are: 1895 1896 ``local`` 1897 Accesses to the filesystem are done by QEMU. 1898 1899 ``proxy`` 1900 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1901 This option is deprecated (since QEMU 8.1) and will be removed in a 1902 future version of QEMU. Use ``local`` instead. 1903 1904 ``synth`` 1905 Synthetic filesystem, only used by QTests. 1906 1907 ``id=id`` 1908 Specifies identifier for the filesystem device 1909 1910 ``path=path`` 1911 Specifies the export path for the file system device. Files 1912 under this path will be available to the 9p client on the guest. 1913 1914 ``security_model=security_model`` 1915 Specifies the security model to be used for this export path. 1916 Supported security models are "passthrough", "mapped-xattr", 1917 "mapped-file" and "none". In "passthrough" security model, files 1918 are stored using the same credentials as they are created on the 1919 guest. This requires QEMU to run as root. In "mapped-xattr" 1920 security model, some of the file attributes like uid, gid, mode 1921 bits and link target are stored as file attributes. For 1922 "mapped-file" these attributes are stored in the hidden 1923 .virtfs\_metadata directory. Directories exported by this 1924 security model cannot interact with other unix tools. "none" 1925 security model is same as passthrough except the sever won't 1926 report failures if it fails to set file attributes like 1927 ownership. Security model is mandatory only for local fsdriver. 1928 Other fsdrivers (like proxy) don't take security model as a 1929 parameter. 1930 1931 ``writeout=writeout`` 1932 This is an optional argument. The only supported value is 1933 "immediate". This means that host page cache will be used to 1934 read and write data but write notification will be sent to the 1935 guest only when the data has been reported as written by the 1936 storage subsystem. 1937 1938 ``readonly=on`` 1939 Enables exporting 9p share as a readonly mount for guests. By 1940 default read-write access is given. 1941 1942 ``socket=socket`` 1943 Enables proxy filesystem driver to use passed socket file for 1944 communicating with virtfs-proxy-helper(1). Usually a helper like 1945 libvirt will create socketpair and pass one of the fds as 1946 sock\_fd. 1947 1948 ``sock_fd`` 1949 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1950 socket descriptor for interfacing with virtfs-proxy-helper(1). 1951 1952 ``fmode=fmode`` 1953 Specifies the default mode for newly created files on the host. 1954 Works only with security models "mapped-xattr" and 1955 "mapped-file". 1956 1957 ``dmode=dmode`` 1958 Specifies the default mode for newly created directories on the 1959 host. Works only with security models "mapped-xattr" and 1960 "mapped-file". 1961 1962 ``mount_tag=mount_tag`` 1963 Specifies the tag name to be used by the guest to mount this 1964 export point. 1965 1966 ``multidevs=multidevs`` 1967 Specifies how to deal with multiple devices being shared with a 1968 9p export. Supported behaviours are either "remap", "forbid" or 1969 "warn". The latter is the default behaviour on which virtfs 9p 1970 expects only one device to be shared with the same export, and 1971 if more than one device is shared and accessed via the same 9p 1972 export then only a warning message is logged (once) by qemu on 1973 host side. In order to avoid file ID collisions on guest you 1974 should either create a separate virtfs export for each device to 1975 be shared with guests (recommended way) or you might use "remap" 1976 instead which allows you to share multiple devices with only one 1977 export instead, which is achieved by remapping the original 1978 inode numbers from host to guest in a way that would prevent 1979 such collisions. Remapping inodes in such use cases is required 1980 because the original device IDs from host are never passed and 1981 exposed on guest. Instead all files of an export shared with 1982 virtfs always share the same device id on guest. So two files 1983 with identical inode numbers but from actually different devices 1984 on host would otherwise cause a file ID collision and hence 1985 potential misbehaviours on guest. "forbid" on the other hand 1986 assumes like "warn" that only one device is shared by the same 1987 export, however it will not only log a warning message but also 1988 deny access to additional devices on guest. Note though that 1989 "forbid" does currently not block all possible file access 1990 operations (e.g. readdir() would still return entries from other 1991 devices). 1992ERST 1993 1994DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1995 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1996 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1997 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1998 " [,timeout=timeout]\n" 1999 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2000 2001SRST 2002``-iscsi`` 2003 Configure iSCSI session parameters. 2004ERST 2005 2006DEFHEADING() 2007 2008DEFHEADING(USB convenience options:) 2009 2010DEF("usb", 0, QEMU_OPTION_usb, 2011 "-usb enable on-board USB host controller (if not enabled by default)\n", 2012 QEMU_ARCH_ALL) 2013SRST 2014``-usb`` 2015 Enable USB emulation on machine types with an on-board USB host 2016 controller (if not enabled by default). Note that on-board USB host 2017 controllers may not support USB 3.0. In this case 2018 ``-device qemu-xhci`` can be used instead on machines with PCI. 2019ERST 2020 2021DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2022 "-usbdevice name add the host or guest USB device 'name'\n", 2023 QEMU_ARCH_ALL) 2024SRST 2025``-usbdevice devname`` 2026 Add the USB device devname, and enable an on-board USB controller 2027 if possible and necessary (just like it can be done via 2028 ``-machine usb=on``). Note that this option is mainly intended for 2029 the user's convenience only. More fine-grained control can be 2030 achieved by selecting a USB host controller (if necessary) and the 2031 desired USB device via the ``-device`` option instead. For example, 2032 instead of using ``-usbdevice mouse`` it is possible to use 2033 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2034 to a USB 3.0 controller instead (at least on machines that support 2035 PCI and do not have an USB controller enabled by default yet). 2036 For more details, see the chapter about 2037 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2038 Possible devices for devname are: 2039 2040 ``braille`` 2041 Braille device. This will use BrlAPI to display the braille 2042 output on a real or fake device (i.e. it also creates a 2043 corresponding ``braille`` chardev automatically beside the 2044 ``usb-braille`` USB device). 2045 2046 ``keyboard`` 2047 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2048 2049 ``mouse`` 2050 Virtual Mouse. This will override the PS/2 mouse emulation when 2051 activated. 2052 2053 ``tablet`` 2054 Pointer device that uses absolute coordinates (like a 2055 touchscreen). This means QEMU is able to report the mouse 2056 position without having to grab the mouse. Also overrides the 2057 PS/2 mouse emulation when activated. 2058 2059 ``wacom-tablet`` 2060 Wacom PenPartner USB tablet. 2061 2062 2063ERST 2064 2065DEFHEADING() 2066 2067DEFHEADING(Display options:) 2068 2069DEF("display", HAS_ARG, QEMU_OPTION_display, 2070#if defined(CONFIG_SPICE) 2071 "-display spice-app[,gl=on|off]\n" 2072#endif 2073#if defined(CONFIG_SDL) 2074 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2075 " [,window-close=on|off]\n" 2076#endif 2077#if defined(CONFIG_GTK) 2078 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2079 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2080 " [,show-menubar=on|off]\n" 2081#endif 2082#if defined(CONFIG_VNC) 2083 "-display vnc=<display>[,<optargs>]\n" 2084#endif 2085#if defined(CONFIG_CURSES) 2086 "-display curses[,charset=<encoding>]\n" 2087#endif 2088#if defined(CONFIG_COCOA) 2089 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2090 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2091 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2092#endif 2093#if defined(CONFIG_OPENGL) 2094 "-display egl-headless[,rendernode=<file>]\n" 2095#endif 2096#if defined(CONFIG_DBUS_DISPLAY) 2097 "-display dbus[,addr=<dbusaddr>]\n" 2098 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2099#endif 2100 "-display none\n" 2101 " select display backend type\n" 2102 " The default display is equivalent to\n " 2103#if defined(CONFIG_GTK) 2104 "\"-display gtk\"\n" 2105#elif defined(CONFIG_SDL) 2106 "\"-display sdl\"\n" 2107#elif defined(CONFIG_COCOA) 2108 "\"-display cocoa\"\n" 2109#elif defined(CONFIG_VNC) 2110 "\"-vnc localhost:0,to=99,id=default\"\n" 2111#else 2112 "\"-display none\"\n" 2113#endif 2114 , QEMU_ARCH_ALL) 2115SRST 2116``-display type`` 2117 Select type of display to use. Use ``-display help`` to list the available 2118 display types. Valid values for type are 2119 2120 ``spice-app[,gl=on|off]`` 2121 Start QEMU as a Spice server and launch the default Spice client 2122 application. The Spice server will redirect the serial consoles 2123 and QEMU monitors. (Since 4.0) 2124 2125 ``dbus`` 2126 Export the display over D-Bus interfaces. (Since 7.0) 2127 2128 The connection is registered with the "org.qemu" name (and queued when 2129 already owned). 2130 2131 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2132 2133 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2134 2135 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2136 will share framebuffers with DMABUF file descriptors). 2137 2138 ``sdl`` 2139 Display video output via SDL (usually in a separate graphics 2140 window; see the SDL documentation for other possibilities). 2141 Valid parameters are: 2142 2143 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2144 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2145 either ``lshift-lctrl-lalt`` or ``rctrl``. 2146 2147 ``gl=on|off|core|es`` : Use OpenGL for displaying 2148 2149 ``show-cursor=on|off`` : Force showing the mouse cursor 2150 2151 ``window-close=on|off`` : Allow to quit qemu with window close button 2152 2153 ``gtk`` 2154 Display video output in a GTK window. This interface provides 2155 drop-down menus and other UI elements to configure and control 2156 the VM during runtime. Valid parameters are: 2157 2158 ``full-screen=on|off`` : Start in fullscreen mode 2159 2160 ``gl=on|off`` : Use OpenGL for displaying 2161 2162 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2163 2164 ``show-tabs=on|off`` : Display the tab bar for switching between the 2165 various graphical interfaces (e.g. VGA and 2166 virtual console character devices) by default. 2167 2168 ``show-cursor=on|off`` : Force showing the mouse cursor 2169 2170 ``window-close=on|off`` : Allow to quit qemu with window close button 2171 2172 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2173 2174 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2175 defaults to "off" 2176 2177 ``curses[,charset=<encoding>]`` 2178 Display video output via curses. For graphics device models 2179 which support a text mode, QEMU can display this output using a 2180 curses/ncurses interface. Nothing is displayed when the graphics 2181 device is in graphical mode or if the graphics device does not 2182 support a text mode. Generally only the VGA device models 2183 support text mode. The font charset used by the guest can be 2184 specified with the ``charset`` option, for example 2185 ``charset=CP850`` for IBM CP850 encoding. The default is 2186 ``CP437``. 2187 2188 ``cocoa`` 2189 Display video output in a Cocoa window. Mac only. This interface 2190 provides drop-down menus and other UI elements to configure and 2191 control the VM during runtime. Valid parameters are: 2192 2193 ``full-grab=on|off`` : Capture all key presses, including system combos. 2194 This requires accessibility permissions, since it 2195 performs a global grab on key events. 2196 (default: off) See 2197 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2198 2199 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2200 key codes match their position on non-Mac 2201 keyboards and you can use Meta/Super and Alt 2202 where you expect them. (default: off) 2203 2204 ``show-cursor=on|off`` : Force showing the mouse cursor 2205 2206 ``left-command-key=on|off`` : Disable forwarding left command key to host 2207 2208 ``full-screen=on|off`` : Start in fullscreen mode 2209 2210 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2211 defaults to "off" 2212 2213 ``egl-headless[,rendernode=<file>]`` 2214 Offload all OpenGL operations to a local DRI device. For any 2215 graphical display, this display needs to be paired with either 2216 VNC or SPICE displays. 2217 2218 ``vnc=<display>`` 2219 Start a VNC server on display <display> 2220 2221 ``none`` 2222 Do not display video output. The guest will still see an 2223 emulated graphics card, but its output will not be displayed to 2224 the QEMU user. This option differs from the -nographic option in 2225 that it only affects what is done with video output; -nographic 2226 also changes the destination of the serial and parallel port 2227 data. 2228ERST 2229 2230DEF("nographic", 0, QEMU_OPTION_nographic, 2231 "-nographic disable graphical output and redirect serial I/Os to console\n", 2232 QEMU_ARCH_ALL) 2233SRST 2234``-nographic`` 2235 Normally, if QEMU is compiled with graphical window support, it 2236 displays output such as guest graphics, guest console, and the QEMU 2237 monitor in a window. With this option, you can totally disable 2238 graphical output so that QEMU is a simple command line application. 2239 The emulated serial port is redirected on the console and muxed with 2240 the monitor (unless redirected elsewhere explicitly). Therefore, you 2241 can still use QEMU to debug a Linux kernel with a serial console. 2242 Use C-a h for help on switching between the console and monitor. 2243ERST 2244 2245#ifdef CONFIG_SPICE 2246DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2247 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2248 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2249 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2250 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2251 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2252 " [,tls-ciphers=<list>]\n" 2253 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2254 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2255 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2256 " [,password-secret=<secret-id>]\n" 2257 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2258 " [,jpeg-wan-compression=[auto|never|always]]\n" 2259 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2260 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2261 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2262 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2263 " [,gl=[on|off]][,rendernode=<file>]\n" 2264 " enable spice\n" 2265 " at least one of {port, tls-port} is mandatory\n", 2266 QEMU_ARCH_ALL) 2267#endif 2268SRST 2269``-spice option[,option[,...]]`` 2270 Enable the spice remote desktop protocol. Valid options are 2271 2272 ``port=<nr>`` 2273 Set the TCP port spice is listening on for plaintext channels. 2274 2275 ``addr=<addr>`` 2276 Set the IP address spice is listening on. Default is any 2277 address. 2278 2279 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2280 Force using the specified IP version. 2281 2282 ``password-secret=<secret-id>`` 2283 Set the ID of the ``secret`` object containing the password 2284 you need to authenticate. 2285 2286 ``sasl=on|off`` 2287 Require that the client use SASL to authenticate with the spice. 2288 The exact choice of authentication method used is controlled 2289 from the system / user's SASL configuration file for the 'qemu' 2290 service. This is typically found in /etc/sasl2/qemu.conf. If 2291 running QEMU as an unprivileged user, an environment variable 2292 SASL\_CONF\_PATH can be used to make it search alternate 2293 locations for the service config. While some SASL auth methods 2294 can also provide data encryption (eg GSSAPI), it is recommended 2295 that SASL always be combined with the 'tls' and 'x509' settings 2296 to enable use of SSL and server certificates. This ensures a 2297 data encryption preventing compromise of authentication 2298 credentials. 2299 2300 ``disable-ticketing=on|off`` 2301 Allow client connects without authentication. 2302 2303 ``disable-copy-paste=on|off`` 2304 Disable copy paste between the client and the guest. 2305 2306 ``disable-agent-file-xfer=on|off`` 2307 Disable spice-vdagent based file-xfer between the client and the 2308 guest. 2309 2310 ``tls-port=<nr>`` 2311 Set the TCP port spice is listening on for encrypted channels. 2312 2313 ``x509-dir=<dir>`` 2314 Set the x509 file directory. Expects same filenames as -vnc 2315 $display,x509=$dir 2316 2317 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2318 The x509 file names can also be configured individually. 2319 2320 ``tls-ciphers=<list>`` 2321 Specify which ciphers to use. 2322 2323 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2324 Force specific channel to be used with or without TLS 2325 encryption. The options can be specified multiple times to 2326 configure multiple channels. The special name "default" can be 2327 used to set the default mode. For channels which are not 2328 explicitly forced into one mode the spice client is allowed to 2329 pick tls/plaintext as he pleases. 2330 2331 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2332 Configure image compression (lossless). Default is auto\_glz. 2333 2334 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2335 Configure wan image compression (lossy for slow links). Default 2336 is auto. 2337 2338 ``streaming-video=[off|all|filter]`` 2339 Configure video stream detection. Default is off. 2340 2341 ``agent-mouse=[on|off]`` 2342 Enable/disable passing mouse events via vdagent. Default is on. 2343 2344 ``playback-compression=[on|off]`` 2345 Enable/disable audio stream compression (using celt 0.5.1). 2346 Default is on. 2347 2348 ``seamless-migration=[on|off]`` 2349 Enable/disable spice seamless migration. Default is off. 2350 2351 ``gl=[on|off]`` 2352 Enable/disable OpenGL context. Default is off. 2353 2354 ``rendernode=<file>`` 2355 DRM render node for OpenGL rendering. If not specified, it will 2356 pick the first available. (Since 2.9) 2357ERST 2358 2359DEF("portrait", 0, QEMU_OPTION_portrait, 2360 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2361 QEMU_ARCH_ALL) 2362SRST 2363``-portrait`` 2364 Rotate graphical output 90 deg left (only PXA LCD). 2365ERST 2366 2367DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2368 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2369 QEMU_ARCH_ALL) 2370SRST 2371``-rotate deg`` 2372 Rotate graphical output some deg left (only PXA LCD). 2373ERST 2374 2375DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2376 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2377 " select video card type\n", QEMU_ARCH_ALL) 2378SRST 2379``-vga type`` 2380 Select type of VGA card to emulate. Valid values for type are 2381 2382 ``cirrus`` 2383 Cirrus Logic GD5446 Video card. All Windows versions starting 2384 from Windows 95 should recognize and use this graphic card. For 2385 optimal performances, use 16 bit color depth in the guest and 2386 the host OS. (This card was the default before QEMU 2.2) 2387 2388 ``std`` 2389 Standard VGA card with Bochs VBE extensions. If your guest OS 2390 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2391 you want to use high resolution modes (>= 1280x1024x16) then you 2392 should use this option. (This card is the default since QEMU 2393 2.2) 2394 2395 ``vmware`` 2396 VMWare SVGA-II compatible adapter. Use it if you have 2397 sufficiently recent XFree86/XOrg server or Windows guest with a 2398 driver for this card. 2399 2400 ``qxl`` 2401 QXL paravirtual graphic card. It is VGA compatible (including 2402 VESA 2.0 VBE support). Works best with qxl guest drivers 2403 installed though. Recommended choice when using the spice 2404 protocol. 2405 2406 ``tcx`` 2407 (sun4m only) Sun TCX framebuffer. This is the default 2408 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2409 colour depths at a fixed resolution of 1024x768. 2410 2411 ``cg3`` 2412 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2413 framebuffer for sun4m machines available in both 1024x768 2414 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2415 wishing to run older Solaris versions. 2416 2417 ``virtio`` 2418 Virtio VGA card. 2419 2420 ``none`` 2421 Disable VGA card. 2422ERST 2423 2424DEF("full-screen", 0, QEMU_OPTION_full_screen, 2425 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2426SRST 2427``-full-screen`` 2428 Start in full screen. 2429ERST 2430 2431DEF("g", HAS_ARG, QEMU_OPTION_g , 2432 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2433 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2434SRST 2435``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2436 Set the initial graphical resolution and depth (PPC, SPARC only). 2437 2438 For PPC the default is 800x600x32. 2439 2440 For SPARC with the TCX graphics device, the default is 1024x768x8 2441 with the option of 1024x768x24. For cgthree, the default is 2442 1024x768x8 with the option of 1152x900x8 for people who wish to use 2443 OBP. 2444ERST 2445 2446#ifdef CONFIG_VNC 2447DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2448 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2449#endif 2450SRST 2451``-vnc display[,option[,option[,...]]]`` 2452 Normally, if QEMU is compiled with graphical window support, it 2453 displays output such as guest graphics, guest console, and the QEMU 2454 monitor in a window. With this option, you can have QEMU listen on 2455 VNC display display and redirect the VGA display over the VNC 2456 session. It is very useful to enable the usb tablet device when 2457 using this option (option ``-device usb-tablet``). When using the 2458 VNC display, you must use the ``-k`` parameter to set the keyboard 2459 layout if you are not using en-us. Valid syntax for the display is 2460 2461 ``to=L`` 2462 With this option, QEMU will try next available VNC displays, 2463 until the number L, if the origianlly defined "-vnc display" is 2464 not available, e.g. port 5900+display is already used by another 2465 application. By default, to=0. 2466 2467 ``host:d`` 2468 TCP connections will only be allowed from host on display d. By 2469 convention the TCP port is 5900+d. Optionally, host can be 2470 omitted in which case the server will accept connections from 2471 any host. 2472 2473 ``unix:path`` 2474 Connections will be allowed over UNIX domain sockets where path 2475 is the location of a unix socket to listen for connections on. 2476 2477 ``none`` 2478 VNC is initialized but not started. The monitor ``change`` 2479 command can be used to later start the VNC server. 2480 2481 Following the display value there may be one or more option flags 2482 separated by commas. Valid options are 2483 2484 ``reverse=on|off`` 2485 Connect to a listening VNC client via a "reverse" connection. 2486 The client is specified by the display. For reverse network 2487 connections (host:d,``reverse``), the d argument is a TCP port 2488 number, not a display number. 2489 2490 ``websocket=on|off`` 2491 Opens an additional TCP listening port dedicated to VNC 2492 Websocket connections. If a bare websocket option is given, the 2493 Websocket port is 5700+display. An alternative port can be 2494 specified with the syntax ``websocket``\ =port. 2495 2496 If host is specified connections will only be allowed from this 2497 host. It is possible to control the websocket listen address 2498 independently, using the syntax ``websocket``\ =host:port. 2499 2500 If no TLS credentials are provided, the websocket connection 2501 runs in unencrypted mode. If TLS credentials are provided, the 2502 websocket connection requires encrypted client connections. 2503 2504 ``password=on|off`` 2505 Require that password based authentication is used for client 2506 connections. 2507 2508 The password must be set separately using the ``set_password`` 2509 command in the :ref:`QEMU monitor`. The 2510 syntax to change your password is: 2511 ``set_password <protocol> <password>`` where <protocol> could be 2512 either "vnc" or "spice". 2513 2514 If you would like to change <protocol> password expiration, you 2515 should use ``expire_password <protocol> <expiration-time>`` 2516 where expiration time could be one of the following options: 2517 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2518 make password expire in 60 seconds, or 1335196800 to make 2519 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2520 this date and time). 2521 2522 You can also use keywords "now" or "never" for the expiration 2523 time to allow <protocol> password to expire immediately or never 2524 expire. 2525 2526 ``password-secret=<secret-id>`` 2527 Require that password based authentication is used for client 2528 connections, using the password provided by the ``secret`` 2529 object identified by ``secret-id``. 2530 2531 ``tls-creds=ID`` 2532 Provides the ID of a set of TLS credentials to use to secure the 2533 VNC server. They will apply to both the normal VNC server socket 2534 and the websocket socket (if enabled). Setting TLS credentials 2535 will cause the VNC server socket to enable the VeNCrypt auth 2536 mechanism. The credentials should have been previously created 2537 using the ``-object tls-creds`` argument. 2538 2539 ``tls-authz=ID`` 2540 Provides the ID of the QAuthZ authorization object against which 2541 the client's x509 distinguished name will validated. This object 2542 is only resolved at time of use, so can be deleted and recreated 2543 on the fly while the VNC server is active. If missing, it will 2544 default to denying access. 2545 2546 ``sasl=on|off`` 2547 Require that the client use SASL to authenticate with the VNC 2548 server. The exact choice of authentication method used is 2549 controlled from the system / user's SASL configuration file for 2550 the 'qemu' service. This is typically found in 2551 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2552 an environment variable SASL\_CONF\_PATH can be used to make it 2553 search alternate locations for the service config. While some 2554 SASL auth methods can also provide data encryption (eg GSSAPI), 2555 it is recommended that SASL always be combined with the 'tls' 2556 and 'x509' settings to enable use of SSL and server 2557 certificates. This ensures a data encryption preventing 2558 compromise of authentication credentials. See the 2559 :ref:`VNC security` section in the System Emulation Users Guide 2560 for details on using SASL authentication. 2561 2562 ``sasl-authz=ID`` 2563 Provides the ID of the QAuthZ authorization object against which 2564 the client's SASL username will validated. This object is only 2565 resolved at time of use, so can be deleted and recreated on the 2566 fly while the VNC server is active. If missing, it will default 2567 to denying access. 2568 2569 ``acl=on|off`` 2570 Legacy method for enabling authorization of clients against the 2571 x509 distinguished name and SASL username. It results in the 2572 creation of two ``authz-list`` objects with IDs of 2573 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2574 objects must be configured with the HMP ACL commands. 2575 2576 This option is deprecated and should no longer be used. The new 2577 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2578 2579 ``lossy=on|off`` 2580 Enable lossy compression methods (gradient, JPEG, ...). If this 2581 option is set, VNC client may receive lossy framebuffer updates 2582 depending on its encoding settings. Enabling this option can 2583 save a lot of bandwidth at the expense of quality. 2584 2585 ``non-adaptive=on|off`` 2586 Disable adaptive encodings. Adaptive encodings are enabled by 2587 default. An adaptive encoding will try to detect frequently 2588 updated screen regions, and send updates in these regions using 2589 a lossy encoding (like JPEG). This can be really helpful to save 2590 bandwidth when playing videos. Disabling adaptive encodings 2591 restores the original static behavior of encodings like Tight. 2592 2593 ``share=[allow-exclusive|force-shared|ignore]`` 2594 Set display sharing policy. 'allow-exclusive' allows clients to 2595 ask for exclusive access. As suggested by the rfb spec this is 2596 implemented by dropping other connections. Connecting multiple 2597 clients in parallel requires all clients asking for a shared 2598 session (vncviewer: -shared switch). This is the default. 2599 'force-shared' disables exclusive client access. Useful for 2600 shared desktop sessions, where you don't want someone forgetting 2601 specify -shared disconnect everybody else. 'ignore' completely 2602 ignores the shared flag and allows everybody connect 2603 unconditionally. Doesn't conform to the rfb spec but is 2604 traditional QEMU behavior. 2605 2606 ``key-delay-ms`` 2607 Set keyboard delay, for key down and key up events, in 2608 milliseconds. Default is 10. Keyboards are low-bandwidth 2609 devices, so this slowdown can help the device and guest to keep 2610 up and not lose events in case events are arriving in bulk. 2611 Possible causes for the latter are flaky network connections, or 2612 scripts for automated testing. 2613 2614 ``audiodev=audiodev`` 2615 Use the specified audiodev when the VNC client requests audio 2616 transmission. When not using an -audiodev argument, this option 2617 must be omitted, otherwise is must be present and specify a 2618 valid audiodev. 2619 2620 ``power-control=on|off`` 2621 Permit the remote client to issue shutdown, reboot or reset power 2622 control requests. 2623ERST 2624 2625ARCHHEADING(, QEMU_ARCH_I386) 2626 2627ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2628 2629DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2630 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2631 QEMU_ARCH_I386) 2632SRST 2633``-win2k-hack`` 2634 Use it when installing Windows 2000 to avoid a disk full bug. After 2635 Windows 2000 is installed, you no longer need this option (this 2636 option slows down the IDE transfers). 2637ERST 2638 2639DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2640 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2641 QEMU_ARCH_I386) 2642SRST 2643``-no-fd-bootchk`` 2644 Disable boot signature checking for floppy disks in BIOS. May be 2645 needed to boot from old floppy disks. 2646ERST 2647 2648DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2649 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2650SRST 2651``-no-acpi`` 2652 Disable ACPI (Advanced Configuration and Power Interface) support. 2653 Use it if your guest OS complains about ACPI problems (PC target 2654 machine only). 2655ERST 2656 2657DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2658 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2659SRST 2660``-no-hpet`` 2661 Disable HPET support. Deprecated, use '-machine hpet=off' instead. 2662ERST 2663 2664DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2665 "-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" 2666 " ACPI table description\n", QEMU_ARCH_I386) 2667SRST 2668``-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]...]`` 2669 Add ACPI table with specified header fields and context from 2670 specified files. For file=, take whole ACPI table from the specified 2671 files, including all ACPI headers (possible overridden by other 2672 options). For data=, only data portion of the table is used, all 2673 header information is specified in the command line. If a SLIC table 2674 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2675 fields will override the same in the RSDT and the FADT (a.k.a. 2676 FACP), in order to ensure the field matches required by the 2677 Microsoft SLIC spec and the ACPI spec. 2678ERST 2679 2680DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2681 "-smbios file=binary\n" 2682 " load SMBIOS entry from binary file\n" 2683 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2684 " [,uefi=on|off]\n" 2685 " specify SMBIOS type 0 fields\n" 2686 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2687 " [,uuid=uuid][,sku=str][,family=str]\n" 2688 " specify SMBIOS type 1 fields\n" 2689 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2690 " [,asset=str][,location=str]\n" 2691 " specify SMBIOS type 2 fields\n" 2692 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2693 " [,sku=str]\n" 2694 " specify SMBIOS type 3 fields\n" 2695 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2696 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2697 " [,processor-id=%d]\n" 2698 " specify SMBIOS type 4 fields\n" 2699 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2700 " specify SMBIOS type 8 fields\n" 2701 "-smbios type=11[,value=str][,path=filename]\n" 2702 " specify SMBIOS type 11 fields\n" 2703 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2704 " [,asset=str][,part=str][,speed=%d]\n" 2705 " specify SMBIOS type 17 fields\n" 2706 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2707 " specify SMBIOS type 41 fields\n", 2708 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2709SRST 2710``-smbios file=binary`` 2711 Load SMBIOS entry from binary file. 2712 2713``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2714 Specify SMBIOS type 0 fields 2715 2716``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2717 Specify SMBIOS type 1 fields 2718 2719``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2720 Specify SMBIOS type 2 fields 2721 2722``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2723 Specify SMBIOS type 3 fields 2724 2725``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2726 Specify SMBIOS type 4 fields 2727 2728``-smbios type=11[,value=str][,path=filename]`` 2729 Specify SMBIOS type 11 fields 2730 2731 This argument can be repeated multiple times, and values are added in the order they are parsed. 2732 Applications intending to use OEM strings data are encouraged to use their application name as 2733 a prefix for the value string. This facilitates passing information for multiple applications 2734 concurrently. 2735 2736 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2737 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2738 2739 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2740 the SMBIOS table in the order in which they appear. 2741 2742 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2743 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2744 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2745 data set, for example, by specifying the serial ID of a block device. 2746 2747 An example passing three strings is 2748 2749 .. parsed-literal:: 2750 2751 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2752 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2753 path=/some/file/with/oemstringsdata.txt 2754 2755 In the guest OS this is visible with the ``dmidecode`` command 2756 2757 .. parsed-literal:: 2758 2759 $ dmidecode -t 11 2760 Handle 0x0E00, DMI type 11, 5 bytes 2761 OEM Strings 2762 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2763 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2764 String 3: myapp:some extra data 2765 2766 2767``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2768 Specify SMBIOS type 17 fields 2769 2770``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2771 Specify SMBIOS type 41 fields 2772 2773 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2774 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2775 position on the PCI bus. 2776 2777 Here is an example of use: 2778 2779 .. parsed-literal:: 2780 2781 -netdev user,id=internet \\ 2782 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2783 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2784 2785 In the guest OS, the device should then appear as ``eno1``: 2786 2787 ..parsed-literal:: 2788 2789 $ ip -brief l 2790 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2791 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2792 2793 Currently, the PCI device has to be attached to the root bus. 2794 2795ERST 2796 2797DEFHEADING() 2798 2799DEFHEADING(Network options:) 2800 2801DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2802#ifdef CONFIG_SLIRP 2803 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2804 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2805 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2806 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2807 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2808#ifndef _WIN32 2809 "[,smb=dir[,smbserver=addr]]\n" 2810#endif 2811 " configure a user mode network backend with ID 'str',\n" 2812 " its DHCP server and optional services\n" 2813#endif 2814#ifdef _WIN32 2815 "-netdev tap,id=str,ifname=name\n" 2816 " configure a host TAP network backend with ID 'str'\n" 2817#else 2818 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2819 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2820 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2821 " [,poll-us=n]\n" 2822 " configure a host TAP network backend with ID 'str'\n" 2823 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2824 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2825 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2826 " to deconfigure it\n" 2827 " use '[down]script=no' to disable script execution\n" 2828 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2829 " configure it\n" 2830 " use 'fd=h' to connect to an already opened TAP interface\n" 2831 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2832 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2833 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2834 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2835 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2836 " use vhost=on to enable experimental in kernel accelerator\n" 2837 " (only has effect for virtio guests which use MSIX)\n" 2838 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2839 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2840 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2841 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2842 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2843 " spent on busy polling for vhost net\n" 2844 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2845 " configure a host TAP network backend with ID 'str' that is\n" 2846 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2847 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2848#endif 2849#ifdef __linux__ 2850 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2851 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2852 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2853 " [,rxcookie=rxcookie][,offset=offset]\n" 2854 " configure a network backend with ID 'str' connected to\n" 2855 " an Ethernet over L2TPv3 pseudowire.\n" 2856 " Linux kernel 3.3+ as well as most routers can talk\n" 2857 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2858 " VM to a router and even VM to Host. It is a nearly-universal\n" 2859 " standard (RFC3931). Note - this implementation uses static\n" 2860 " pre-configured tunnels (same as the Linux kernel).\n" 2861 " use 'src=' to specify source address\n" 2862 " use 'dst=' to specify destination address\n" 2863 " use 'udp=on' to specify udp encapsulation\n" 2864 " use 'srcport=' to specify source udp port\n" 2865 " use 'dstport=' to specify destination udp port\n" 2866 " use 'ipv6=on' to force v6\n" 2867 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2868 " well as a weak security measure\n" 2869 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2870 " use 'txcookie=0x012345678' to specify a txcookie\n" 2871 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2872 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2873 " use 'pincounter=on' to work around broken counter handling in peer\n" 2874 " use 'offset=X' to add an extra offset between header and data\n" 2875#endif 2876 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2877 " configure a network backend to connect to another network\n" 2878 " using a socket connection\n" 2879 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2880 " configure a network backend to connect to a multicast maddr and port\n" 2881 " use 'localaddr=addr' to specify the host address to send packets from\n" 2882 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2883 " configure a network backend to connect to another network\n" 2884 " using an UDP tunnel\n" 2885 "-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" 2886 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2887 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2888 " configure a network backend to connect to another network\n" 2889 " using a socket connection in stream mode.\n" 2890 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2891 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2892 " configure a network backend to connect to a multicast maddr and port\n" 2893 " use ``local.host=addr`` to specify the host address to send packets from\n" 2894 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2895 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2896 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2897 " configure a network backend to connect to another network\n" 2898 " using an UDP tunnel\n" 2899#ifdef CONFIG_VDE 2900 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2901 " configure a network backend to connect to port 'n' of a vde switch\n" 2902 " running on host and listening for incoming connections on 'socketpath'.\n" 2903 " Use group 'groupname' and mode 'octalmode' to change default\n" 2904 " ownership and permissions for communication port.\n" 2905#endif 2906#ifdef CONFIG_NETMAP 2907 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2908 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2909 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2910 " netmap device, defaults to '/dev/netmap')\n" 2911#endif 2912#ifdef CONFIG_AF_XDP 2913 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2914 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2915 " attach to the existing network interface 'name' with AF_XDP socket\n" 2916 " use 'mode=MODE' to specify an XDP program attach mode\n" 2917 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2918 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2919 " with inhibit=on,\n" 2920 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2921 " added to a socket map in XDP program. One socket per queue.\n" 2922 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2923 " use 'start-queue=m' to specify the first queue that should be used\n" 2924#endif 2925#ifdef CONFIG_POSIX 2926 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2927 " configure a vhost-user network, backed by a chardev 'dev'\n" 2928#endif 2929#ifdef __linux__ 2930 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2931 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2932 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2933 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2934#endif 2935#ifdef CONFIG_VMNET 2936 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2937 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2938 " configure a vmnet network backend in host mode with ID 'str',\n" 2939 " isolate this interface from others with 'isolated',\n" 2940 " configure the address range and choose a subnet mask,\n" 2941 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2942 " vmnet-host interfaces within this isolated network\n" 2943 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2944 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2945 " configure a vmnet network backend in shared mode with ID 'str',\n" 2946 " configure the address range and choose a subnet mask,\n" 2947 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2948 " isolate this interface from others with 'isolated'\n" 2949 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2950 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2951 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2952 " isolate this interface from others with 'isolated'\n" 2953#endif 2954 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2955 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2956DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2957 "-nic [tap|bridge|" 2958#ifdef CONFIG_SLIRP 2959 "user|" 2960#endif 2961#ifdef __linux__ 2962 "l2tpv3|" 2963#endif 2964#ifdef CONFIG_VDE 2965 "vde|" 2966#endif 2967#ifdef CONFIG_NETMAP 2968 "netmap|" 2969#endif 2970#ifdef CONFIG_AF_XDP 2971 "af-xdp|" 2972#endif 2973#ifdef CONFIG_POSIX 2974 "vhost-user|" 2975#endif 2976#ifdef CONFIG_VMNET 2977 "vmnet-host|vmnet-shared|vmnet-bridged|" 2978#endif 2979 "socket][,option][,...][mac=macaddr]\n" 2980 " initialize an on-board / default host NIC (using MAC address\n" 2981 " macaddr) and connect it to the given host network backend\n" 2982 "-nic none use it alone to have zero network devices (the default is to\n" 2983 " provided a 'user' network connection)\n", 2984 QEMU_ARCH_ALL) 2985DEF("net", HAS_ARG, QEMU_OPTION_net, 2986 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2987 " configure or create an on-board (or machine default) NIC and\n" 2988 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2989 "-net [" 2990#ifdef CONFIG_SLIRP 2991 "user|" 2992#endif 2993 "tap|" 2994 "bridge|" 2995#ifdef CONFIG_VDE 2996 "vde|" 2997#endif 2998#ifdef CONFIG_NETMAP 2999 "netmap|" 3000#endif 3001#ifdef CONFIG_AF_XDP 3002 "af-xdp|" 3003#endif 3004#ifdef CONFIG_VMNET 3005 "vmnet-host|vmnet-shared|vmnet-bridged|" 3006#endif 3007 "socket][,option][,option][,...]\n" 3008 " old way to initialize a host network interface\n" 3009 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 3010SRST 3011``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 3012 This option is a shortcut for configuring both the on-board 3013 (default) guest NIC hardware and the host network backend in one go. 3014 The host backend options are the same as with the corresponding 3015 ``-netdev`` options below. The guest NIC model can be set with 3016 ``model=modelname``. Use ``model=help`` to list the available device 3017 types. The hardware MAC address can be set with ``mac=macaddr``. 3018 3019 The following two example do exactly the same, to show how ``-nic`` 3020 can be used to shorten the command line length: 3021 3022 .. parsed-literal:: 3023 3024 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3025 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3026 3027``-nic none`` 3028 Indicate that no network devices should be configured. It is used to 3029 override the default configuration (default NIC with "user" host 3030 network backend) which is activated if no other networking options 3031 are provided. 3032 3033``-netdev user,id=id[,option][,option][,...]`` 3034 Configure user mode host network backend which requires no 3035 administrator privilege to run. Valid options are: 3036 3037 ``id=id`` 3038 Assign symbolic name for use in monitor commands. 3039 3040 ``ipv4=on|off and ipv6=on|off`` 3041 Specify that either IPv4 or IPv6 must be enabled. If neither is 3042 specified both protocols are enabled. 3043 3044 ``net=addr[/mask]`` 3045 Set IP network address the guest will see. Optionally specify 3046 the netmask, either in the form a.b.c.d or as number of valid 3047 top-most bits. Default is 10.0.2.0/24. 3048 3049 ``host=addr`` 3050 Specify the guest-visible address of the host. Default is the 3051 2nd IP in the guest network, i.e. x.x.x.2. 3052 3053 ``ipv6-net=addr[/int]`` 3054 Set IPv6 network address the guest will see (default is 3055 fec0::/64). The network prefix is given in the usual hexadecimal 3056 IPv6 address notation. The prefix size is optional, and is given 3057 as the number of valid top-most bits (default is 64). 3058 3059 ``ipv6-host=addr`` 3060 Specify the guest-visible IPv6 address of the host. Default is 3061 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3062 3063 ``restrict=on|off`` 3064 If this option is enabled, the guest will be isolated, i.e. it 3065 will not be able to contact the host and no guest IP packets 3066 will be routed over the host to the outside. This option does 3067 not affect any explicitly set forwarding rules. 3068 3069 ``hostname=name`` 3070 Specifies the client hostname reported by the built-in DHCP 3071 server. 3072 3073 ``dhcpstart=addr`` 3074 Specify the first of the 16 IPs the built-in DHCP server can 3075 assign. Default is the 15th to 31st IP in the guest network, 3076 i.e. x.x.x.15 to x.x.x.31. 3077 3078 ``dns=addr`` 3079 Specify the guest-visible address of the virtual nameserver. The 3080 address must be different from the host address. Default is the 3081 3rd IP in the guest network, i.e. x.x.x.3. 3082 3083 ``ipv6-dns=addr`` 3084 Specify the guest-visible address of the IPv6 virtual 3085 nameserver. The address must be different from the host address. 3086 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3087 3088 ``dnssearch=domain`` 3089 Provides an entry for the domain-search list sent by the 3090 built-in DHCP server. More than one domain suffix can be 3091 transmitted by specifying this option multiple times. If 3092 supported, this will cause the guest to automatically try to 3093 append the given domain suffix(es) in case a domain name can not 3094 be resolved. 3095 3096 Example: 3097 3098 .. parsed-literal:: 3099 3100 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3101 3102 ``domainname=domain`` 3103 Specifies the client domain name reported by the built-in DHCP 3104 server. 3105 3106 ``tftp=dir`` 3107 When using the user mode network stack, activate a built-in TFTP 3108 server. The files in dir will be exposed as the root of a TFTP 3109 server. The TFTP client on the guest must be configured in 3110 binary mode (use the command ``bin`` of the Unix TFTP client). 3111 3112 ``tftp-server-name=name`` 3113 In BOOTP reply, broadcast name as the "TFTP server name" 3114 (RFC2132 option 66). This can be used to advise the guest to 3115 load boot files or configurations from a different server than 3116 the host address. 3117 3118 ``bootfile=file`` 3119 When using the user mode network stack, broadcast file as the 3120 BOOTP filename. In conjunction with ``tftp``, this can be used 3121 to network boot a guest from a local directory. 3122 3123 Example (using pxelinux): 3124 3125 .. parsed-literal:: 3126 3127 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3128 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3129 3130 ``smb=dir[,smbserver=addr]`` 3131 When using the user mode network stack, activate a built-in SMB 3132 server so that Windows OSes can access to the host files in 3133 ``dir`` transparently. The IP address of the SMB server can be 3134 set to addr. By default the 4th IP in the guest network is used, 3135 i.e. x.x.x.4. 3136 3137 In the guest Windows OS, the line: 3138 3139 :: 3140 3141 10.0.2.4 smbserver 3142 3143 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3144 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3145 NT/2000). 3146 3147 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3148 3149 Note that a SAMBA server must be installed on the host OS. 3150 3151 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3152 Redirect incoming TCP or UDP connections to the host port 3153 hostport to the guest IP address guestaddr on guest port 3154 guestport. If guestaddr is not specified, its value is x.x.x.15 3155 (default first address given by the built-in DHCP server). By 3156 specifying hostaddr, the rule can be bound to a specific host 3157 interface. If no connection type is set, TCP is used. This 3158 option can be given multiple times. 3159 3160 For example, to redirect host X11 connection from screen 1 to 3161 guest screen 0, use the following: 3162 3163 .. parsed-literal:: 3164 3165 # on the host 3166 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3167 # this host xterm should open in the guest X11 server 3168 xterm -display :1 3169 3170 To redirect telnet connections from host port 5555 to telnet 3171 port on the guest, use the following: 3172 3173 .. parsed-literal:: 3174 3175 # on the host 3176 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3177 telnet localhost 5555 3178 3179 Then when you use on the host ``telnet localhost 5555``, you 3180 connect to the guest telnet server. 3181 3182 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3183 Forward guest TCP connections to the IP address server on port 3184 port to the character device dev or to a program executed by 3185 cmd:command which gets spawned for each connection. This option 3186 can be given multiple times. 3187 3188 You can either use a chardev directly and have that one used 3189 throughout QEMU's lifetime, like in the following example: 3190 3191 .. parsed-literal:: 3192 3193 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3194 # the guest accesses it 3195 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3196 3197 Or you can execute a command on every TCP connection established 3198 by the guest, so that QEMU behaves similar to an inetd process 3199 for that virtual server: 3200 3201 .. parsed-literal:: 3202 3203 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3204 # and connect the TCP stream to its stdin/stdout 3205 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3206 3207``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3208 Configure a host TAP network backend with ID id. 3209 3210 Use the network script file to configure it and the network script 3211 dfile to deconfigure it. If name is not provided, the OS 3212 automatically provides one. The default network configure script is 3213 ``/etc/qemu-ifup`` and the default network deconfigure script is 3214 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3215 disable script execution. 3216 3217 If running QEMU as an unprivileged user, use the network helper 3218 to configure the TAP interface and attach it to the bridge. 3219 The default network helper executable is 3220 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3221 ``br0``. 3222 3223 ``fd``\ =h can be used to specify the handle of an already opened 3224 host TAP interface. 3225 3226 Examples: 3227 3228 .. parsed-literal:: 3229 3230 #launch a QEMU instance with the default network script 3231 |qemu_system| linux.img -nic tap 3232 3233 .. parsed-literal:: 3234 3235 #launch a QEMU instance with two NICs, each one connected 3236 #to a TAP device 3237 |qemu_system| linux.img \\ 3238 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3239 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3240 3241 .. parsed-literal:: 3242 3243 #launch a QEMU instance with the default network helper to 3244 #connect a TAP device to bridge br0 3245 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3246 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3247 3248``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3249 Connect a host TAP network interface to a host bridge device. 3250 3251 Use the network helper helper to configure the TAP interface and 3252 attach it to the bridge. The default network helper executable is 3253 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3254 ``br0``. 3255 3256 Examples: 3257 3258 .. parsed-literal:: 3259 3260 #launch a QEMU instance with the default network helper to 3261 #connect a TAP device to bridge br0 3262 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3263 3264 .. parsed-literal:: 3265 3266 #launch a QEMU instance with the default network helper to 3267 #connect a TAP device to bridge qemubr0 3268 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3269 3270``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3271 This host network backend can be used to connect the guest's network 3272 to another QEMU virtual machine using a TCP socket connection. If 3273 ``listen`` is specified, QEMU waits for incoming connections on port 3274 (host is optional). ``connect`` is used to connect to another QEMU 3275 instance using the ``listen`` option. ``fd``\ =h specifies an 3276 already opened TCP socket. 3277 3278 Example: 3279 3280 .. parsed-literal:: 3281 3282 # launch a first QEMU instance 3283 |qemu_system| linux.img \\ 3284 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3285 -netdev socket,id=n1,listen=:1234 3286 # connect the network of this instance to the network of the first instance 3287 |qemu_system| linux.img \\ 3288 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3289 -netdev socket,id=n2,connect=127.0.0.1:1234 3290 3291``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3292 Configure a socket host network backend to share the guest's network 3293 traffic with another QEMU virtual machines using a UDP multicast 3294 socket, effectively making a bus for every QEMU with same multicast 3295 address maddr and port. NOTES: 3296 3297 1. Several QEMU can be running on different hosts and share same bus 3298 (assuming correct multicast setup for these hosts). 3299 3300 2. mcast support is compatible with User Mode Linux (argument 3301 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3302 3303 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3304 3305 Example: 3306 3307 .. parsed-literal:: 3308 3309 # launch one QEMU instance 3310 |qemu_system| linux.img \\ 3311 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3312 -netdev socket,id=n1,mcast=230.0.0.1:1234 3313 # launch another QEMU instance on same "bus" 3314 |qemu_system| linux.img \\ 3315 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3316 -netdev socket,id=n2,mcast=230.0.0.1:1234 3317 # launch yet another QEMU instance on same "bus" 3318 |qemu_system| linux.img \\ 3319 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3320 -netdev socket,id=n3,mcast=230.0.0.1:1234 3321 3322 Example (User Mode Linux compat.): 3323 3324 .. parsed-literal:: 3325 3326 # launch QEMU instance (note mcast address selected is UML's default) 3327 |qemu_system| linux.img \\ 3328 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3329 -netdev socket,id=n1,mcast=239.192.168.1:1102 3330 # launch UML 3331 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3332 3333 Example (send packets from host's 1.2.3.4): 3334 3335 .. parsed-literal:: 3336 3337 |qemu_system| linux.img \\ 3338 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3339 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3340 3341``-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]`` 3342 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3343 is a popular protocol to transport Ethernet (and other Layer 2) data 3344 frames between two systems. It is present in routers, firewalls and 3345 the Linux kernel (from version 3.3 onwards). 3346 3347 This transport allows a VM to communicate to another VM, router or 3348 firewall directly. 3349 3350 ``src=srcaddr`` 3351 source address (mandatory) 3352 3353 ``dst=dstaddr`` 3354 destination address (mandatory) 3355 3356 ``udp`` 3357 select udp encapsulation (default is ip). 3358 3359 ``srcport=srcport`` 3360 source udp port. 3361 3362 ``dstport=dstport`` 3363 destination udp port. 3364 3365 ``ipv6`` 3366 force v6, otherwise defaults to v4. 3367 3368 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3369 Cookies are a weak form of security in the l2tpv3 specification. 3370 Their function is mostly to prevent misconfiguration. By default 3371 they are 32 bit. 3372 3373 ``cookie64`` 3374 Set cookie size to 64 bit instead of the default 32 3375 3376 ``counter=off`` 3377 Force a 'cut-down' L2TPv3 with no counter as in 3378 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3379 3380 ``pincounter=on`` 3381 Work around broken counter handling in peer. This may also help 3382 on networks which have packet reorder. 3383 3384 ``offset=offset`` 3385 Add an extra offset between header and data 3386 3387 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3388 the bridge br-lan on the remote Linux host 1.2.3.4: 3389 3390 .. parsed-literal:: 3391 3392 # Setup tunnel on linux host using raw ip as encapsulation 3393 # on 1.2.3.4 3394 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3395 encap udp udp_sport 16384 udp_dport 16384 3396 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3397 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3398 ifconfig vmtunnel0 mtu 1500 3399 ifconfig vmtunnel0 up 3400 brctl addif br-lan vmtunnel0 3401 3402 3403 # on 4.3.2.1 3404 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3405 3406 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3407 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3408 3409``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3410 Configure VDE backend to connect to PORT n of a vde switch running 3411 on host and listening for incoming connections on socketpath. Use 3412 GROUP groupname and MODE octalmode to change default ownership and 3413 permissions for communication port. This option is only available if 3414 QEMU has been compiled with vde support enabled. 3415 3416 Example: 3417 3418 .. parsed-literal:: 3419 3420 # launch vde switch 3421 vde_switch -F -sock /tmp/myswitch 3422 # launch QEMU instance 3423 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3424 3425``-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]`` 3426 Configure AF_XDP backend to connect to a network interface 'name' 3427 using AF_XDP socket. A specific program attach mode for a default 3428 XDP program can be forced with 'mode', defaults to best-effort, 3429 where the likely most performant mode will be in use. Number of queues 3430 'n' should generally match the number or queues in the interface, 3431 defaults to 1. Traffic arriving on non-configured device queues will 3432 not be delivered to the network backend. 3433 3434 .. parsed-literal:: 3435 3436 # set number of queues to 4 3437 ethtool -L eth0 combined 4 3438 # launch QEMU instance 3439 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3440 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3441 3442 'start-queue' option can be specified if a particular range of queues 3443 [m, m + n] should be in use. For example, this is may be necessary in 3444 order to use certain NICs in native mode. Kernel allows the driver to 3445 create a separate set of XDP queues on top of regular ones, and only 3446 these queues can be used for AF_XDP sockets. NICs that work this way 3447 may also require an additional traffic redirection with ethtool to these 3448 special queues. 3449 3450 .. parsed-literal:: 3451 3452 # set number of queues to 1 3453 ethtool -L eth0 combined 1 3454 # redirect all the traffic to the second queue (id: 1) 3455 # note: drivers may require non-empty key/mask pair. 3456 ethtool -N eth0 flow-type ether \\ 3457 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3458 ethtool -N eth0 flow-type ether \\ 3459 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3460 # launch QEMU instance 3461 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3462 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3463 3464 XDP program can also be loaded externally. In this case 'inhibit' option 3465 should be set to 'on' and 'sock-fds' provided with file descriptors for 3466 already open but not bound XDP sockets already added to a socket map for 3467 corresponding queues. One socket per queue. 3468 3469 .. parsed-literal:: 3470 3471 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3472 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3473 3474``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3475 Establish a vhost-user netdev, backed by a chardev id. The chardev 3476 should be a unix domain socket backed one. The vhost-user uses a 3477 specifically defined protocol to pass vhost ioctl replacement 3478 messages to an application on the other end of the socket. On 3479 non-MSIX guests, the feature can be forced with vhostforce. Use 3480 'queues=n' to specify the number of queues to be created for 3481 multiqueue vhost-user. 3482 3483 Example: 3484 3485 :: 3486 3487 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3488 -numa node,memdev=mem \ 3489 -chardev socket,id=chr0,path=/path/to/socket \ 3490 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3491 -device virtio-net-pci,netdev=net0 3492 3493``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3494 Establish a vhost-vdpa netdev. 3495 3496 vDPA device is a device that uses a datapath which complies with 3497 the virtio specifications with a vendor specific control path. 3498 vDPA devices can be both physically located on the hardware or 3499 emulated by software. 3500 3501``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3502 Create a hub port on the emulated hub with ID hubid. 3503 3504 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3505 instead of a single netdev. Alternatively, you can also connect the 3506 hubport to another netdev with ID nd by using the ``netdev=nd`` 3507 option. 3508 3509``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3510 Legacy option to configure or create an on-board (or machine 3511 default) Network Interface Card(NIC) and connect it either to the 3512 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3513 If model is omitted, then the default NIC model associated with the 3514 machine type is used. Note that the default NIC model may change in 3515 future QEMU releases, so it is highly recommended to always specify 3516 a model. Optionally, the MAC address can be changed to mac, the 3517 device address set to addr (PCI cards only), and a name can be 3518 assigned for use in monitor commands. Optionally, for PCI cards, you 3519 can specify the number v of MSI-X vectors that the card should have; 3520 this option currently only affects virtio cards; set v = 0 to 3521 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3522 created. QEMU can emulate several different models of network card. 3523 Use ``-net nic,model=help`` for a list of available devices for your 3524 target. 3525 3526``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3527 Configure a host network backend (with the options corresponding to 3528 the same ``-netdev`` option) and connect it to the emulated hub 0 3529 (the default hub). Use name to specify the name of the hub port. 3530ERST 3531 3532DEFHEADING() 3533 3534DEFHEADING(Character device options:) 3535 3536DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3537 "-chardev help\n" 3538 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3539 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3540 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3541 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3542 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3543 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3544 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3545 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3546 " [,logfile=PATH][,logappend=on|off]\n" 3547 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3548 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3549 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3550 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3551 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3552 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3553#ifdef _WIN32 3554 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3555 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3556#else 3557 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3558 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3559#endif 3560#ifdef CONFIG_BRLAPI 3561 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3562#endif 3563#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3564 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3565 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3566#endif 3567#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3568 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3569#endif 3570#if defined(CONFIG_SPICE) 3571 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3572 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3573#endif 3574 , QEMU_ARCH_ALL 3575) 3576 3577SRST 3578The general form of a character device option is: 3579 3580``-chardev backend,id=id[,mux=on|off][,options]`` 3581 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3582 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3583 ``pty``, ``stdio``, ``braille``, ``parallel``, 3584 ``spicevmc``, ``spiceport``. The specific backend will determine the 3585 applicable options. 3586 3587 Use ``-chardev help`` to print all available chardev backend types. 3588 3589 All devices must have an id, which can be any string up to 127 3590 characters long. It is used to uniquely identify this device in 3591 other command line directives. 3592 3593 A character device may be used in multiplexing mode by multiple 3594 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3595 a "1:N" device, and here the "1" end is your specified chardev 3596 backend, and the "N" end is the various parts of QEMU that can talk 3597 to a chardev. If you create a chardev with ``id=myid`` and 3598 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3599 and you can then configure multiple front ends to use that chardev 3600 ID for their input/output. Up to four different front ends can be 3601 connected to a single multiplexed chardev. (Without multiplexing 3602 enabled, a chardev can only be used by a single front end.) For 3603 instance you could use this to allow a single stdio chardev to be 3604 used by two serial ports and the QEMU monitor: 3605 3606 :: 3607 3608 -chardev stdio,mux=on,id=char0 \ 3609 -mon chardev=char0,mode=readline \ 3610 -serial chardev:char0 \ 3611 -serial chardev:char0 3612 3613 You can have more than one multiplexer in a system configuration; 3614 for instance you could have a TCP port multiplexed between UART 0 3615 and UART 1, and stdio multiplexed between the QEMU monitor and a 3616 parallel port: 3617 3618 :: 3619 3620 -chardev stdio,mux=on,id=char0 \ 3621 -mon chardev=char0,mode=readline \ 3622 -parallel chardev:char0 \ 3623 -chardev tcp,...,mux=on,id=char1 \ 3624 -serial chardev:char1 \ 3625 -serial chardev:char1 3626 3627 When you're using a multiplexed character device, some escape 3628 sequences are interpreted in the input. See the chapter about 3629 :ref:`keys in the character backend multiplexer` in the 3630 System Emulation Users Guide for more details. 3631 3632 Note that some other command line options may implicitly create 3633 multiplexed character backends; for instance ``-serial mon:stdio`` 3634 creates a multiplexed stdio backend connected to the serial port and 3635 the QEMU monitor, and ``-nographic`` also multiplexes the console 3636 and the monitor to stdio. 3637 3638 There is currently no support for multiplexing in the other 3639 direction (where a single QEMU front end takes input and output from 3640 multiple chardevs). 3641 3642 Every backend supports the ``logfile`` option, which supplies the 3643 path to a file to record all data transmitted via the backend. The 3644 ``logappend`` option controls whether the log file will be truncated 3645 or appended to when opened. 3646 3647The available backends are: 3648 3649``-chardev null,id=id`` 3650 A void device. This device will not emit any data, and will drop any 3651 data it receives. The null backend does not take any options. 3652 3653``-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]`` 3654 Create a two-way stream socket, which can be either a TCP or a unix 3655 socket. A unix socket will be created if ``path`` is specified. 3656 Behaviour is undefined if TCP options are specified for a unix 3657 socket. 3658 3659 ``server=on|off`` specifies that the socket shall be a listening socket. 3660 3661 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3662 to connect to a listening socket. 3663 3664 ``telnet=on|off`` specifies that traffic on the socket should interpret 3665 telnet escape sequences. 3666 3667 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3668 communication. 3669 3670 ``reconnect`` sets the timeout for reconnecting on non-server 3671 sockets when the remote end goes away. qemu will delay this many 3672 seconds and then attempt to reconnect. Zero disables reconnecting, 3673 and is the default. 3674 3675 ``tls-creds`` requests enablement of the TLS protocol for 3676 encryption, and specifies the id of the TLS credentials to use for 3677 the handshake. The credentials must be previously created with the 3678 ``-object tls-creds`` argument. 3679 3680 ``tls-auth`` provides the ID of the QAuthZ authorization object 3681 against which the client's x509 distinguished name will be 3682 validated. This object is only resolved at time of use, so can be 3683 deleted and recreated on the fly while the chardev server is active. 3684 If missing, it will default to denying access. 3685 3686 TCP and unix socket options are given below: 3687 3688 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3689 ``host`` for a listening socket specifies the local address to 3690 be bound. For a connecting socket species the remote host to 3691 connect to. ``host`` is optional for listening sockets. If not 3692 specified it defaults to ``0.0.0.0``. 3693 3694 ``port`` for a listening socket specifies the local port to be 3695 bound. For a connecting socket specifies the port on the remote 3696 host to connect to. ``port`` can be given as either a port 3697 number or a service name. ``port`` is required. 3698 3699 ``to`` is only relevant to listening sockets. If it is 3700 specified, and ``port`` cannot be bound, QEMU will attempt to 3701 bind to subsequent ports up to and including ``to`` until it 3702 succeeds. ``to`` must be specified as a port number. 3703 3704 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3705 or IPv6 must be used. If neither is specified the socket may 3706 use either protocol. 3707 3708 ``nodelay=on|off`` disables the Nagle algorithm. 3709 3710 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3711 ``path`` specifies the local path of the unix socket. ``path`` 3712 is required. 3713 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3714 rather than the filesystem. Optional, defaults to false. 3715 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3716 rather than the full sun_path length. Optional, defaults to true. 3717 3718``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3719 Sends all traffic from the guest to a remote host over UDP. 3720 3721 ``host`` specifies the remote host to connect to. If not specified 3722 it defaults to ``localhost``. 3723 3724 ``port`` specifies the port on the remote host to connect to. 3725 ``port`` is required. 3726 3727 ``localaddr`` specifies the local address to bind to. If not 3728 specified it defaults to ``0.0.0.0``. 3729 3730 ``localport`` specifies the local port to bind to. If not specified 3731 any available local port will be used. 3732 3733 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3734 If neither is specified the device may use either protocol. 3735 3736``-chardev msmouse,id=id`` 3737 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3738 does not take any options. 3739 3740``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3741 Connect to a QEMU text console. ``vc`` may optionally be given a 3742 specific size. 3743 3744 ``width`` and ``height`` specify the width and height respectively 3745 of the console, in pixels. 3746 3747 ``cols`` and ``rows`` specify that the console be sized to fit a 3748 text console with the given dimensions. 3749 3750``-chardev ringbuf,id=id[,size=size]`` 3751 Create a ring buffer with fixed size ``size``. size must be a power 3752 of two and defaults to ``64K``. 3753 3754``-chardev file,id=id,path=path[,input-path=input-path]`` 3755 Log all traffic received from the guest to a file. 3756 3757 ``path`` specifies the path of the file to be opened. This file will 3758 be created if it does not already exist, and overwritten if it does. 3759 ``path`` is required. 3760 3761 If ``input-path`` is specified, this is the path of a second file 3762 which will be used for input. If ``input-path`` is not specified, 3763 no input will be available from the chardev. 3764 3765 Note that ``input-path`` is not supported on Windows hosts. 3766 3767``-chardev pipe,id=id,path=path`` 3768 Create a two-way connection to the guest. The behaviour differs 3769 slightly between Windows hosts and other hosts: 3770 3771 On Windows, a single duplex pipe will be created at 3772 ``\\.pipe\path``. 3773 3774 On other hosts, 2 pipes will be created called ``path.in`` and 3775 ``path.out``. Data written to ``path.in`` will be received by the 3776 guest. Data written by the guest can be read from ``path.out``. QEMU 3777 will not create these fifos, and requires them to be present. 3778 3779 ``path`` forms part of the pipe path as described above. ``path`` is 3780 required. 3781 3782``-chardev console,id=id`` 3783 Send traffic from the guest to QEMU's standard output. ``console`` 3784 does not take any options. 3785 3786 ``console`` is only available on Windows hosts. 3787 3788``-chardev serial,id=id,path=path`` 3789 Send traffic from the guest to a serial device on the host. 3790 3791 On Unix hosts serial will actually accept any tty device, not only 3792 serial lines. 3793 3794 ``path`` specifies the name of the serial device to open. 3795 3796``-chardev pty,id=id`` 3797 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3798 does not take any options. 3799 3800 ``pty`` is not available on Windows hosts. 3801 3802``-chardev stdio,id=id[,signal=on|off]`` 3803 Connect to standard input and standard output of the QEMU process. 3804 3805 ``signal`` controls if signals are enabled on the terminal, that 3806 includes exiting QEMU with the key sequence Control-c. This option 3807 is enabled by default, use ``signal=off`` to disable it. 3808 3809``-chardev braille,id=id`` 3810 Connect to a local BrlAPI server. ``braille`` does not take any 3811 options. 3812 3813``-chardev parallel,id=id,path=path`` 3814 \ 3815 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3816 hosts. 3817 3818 Connect to a local parallel port. 3819 3820 ``path`` specifies the path to the parallel port device. ``path`` is 3821 required. 3822 3823``-chardev spicevmc,id=id,debug=debug,name=name`` 3824 ``spicevmc`` is only available when spice support is built in. 3825 3826 ``debug`` debug level for spicevmc 3827 3828 ``name`` name of spice channel to connect to 3829 3830 Connect to a spice virtual machine channel, such as vdiport. 3831 3832``-chardev spiceport,id=id,debug=debug,name=name`` 3833 ``spiceport`` is only available when spice support is built in. 3834 3835 ``debug`` debug level for spicevmc 3836 3837 ``name`` name of spice port to connect to 3838 3839 Connect to a spice port, allowing a Spice client to handle the 3840 traffic identified by a name (preferably a fqdn). 3841ERST 3842 3843DEFHEADING() 3844 3845#ifdef CONFIG_TPM 3846DEFHEADING(TPM device options:) 3847 3848DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3849 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3850 " use path to provide path to a character device; default is /dev/tpm0\n" 3851 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3852 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3853 "-tpmdev emulator,id=id,chardev=dev\n" 3854 " configure the TPM device using chardev backend\n", 3855 QEMU_ARCH_ALL) 3856SRST 3857The general form of a TPM device option is: 3858 3859``-tpmdev backend,id=id[,options]`` 3860 The specific backend type will determine the applicable options. The 3861 ``-tpmdev`` option creates the TPM backend and requires a 3862 ``-device`` option that specifies the TPM frontend interface model. 3863 3864 Use ``-tpmdev help`` to print all available TPM backend types. 3865 3866The available backends are: 3867 3868``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3869 (Linux-host only) Enable access to the host's TPM using the 3870 passthrough driver. 3871 3872 ``path`` specifies the path to the host's TPM device, i.e., on a 3873 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3874 default ``/dev/tpm0`` is used. 3875 3876 ``cancel-path`` specifies the path to the host TPM device's sysfs 3877 entry allowing for cancellation of an ongoing TPM command. 3878 ``cancel-path`` is optional and by default QEMU will search for the 3879 sysfs entry to use. 3880 3881 Some notes about using the host's TPM with the passthrough driver: 3882 3883 The TPM device accessed by the passthrough driver must not be used 3884 by any other application on the host. 3885 3886 Since the host's firmware (BIOS/UEFI) has already initialized the 3887 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3888 the TPM again and may therefore not show a TPM-specific menu that 3889 would otherwise allow the user to configure the TPM, e.g., allow the 3890 user to enable/disable or activate/deactivate the TPM. Further, if 3891 TPM ownership is released from within a VM then the host's TPM will 3892 get disabled and deactivated. To enable and activate the TPM again 3893 afterwards, the host has to be rebooted and the user is required to 3894 enter the firmware's menu to enable and activate the TPM. If the TPM 3895 is left disabled and/or deactivated most TPM commands will fail. 3896 3897 To create a passthrough TPM use the following two options: 3898 3899 :: 3900 3901 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3902 3903 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3904 ``tpmdev=tpm0`` in the device option. 3905 3906``-tpmdev emulator,id=id,chardev=dev`` 3907 (Linux-host only) Enable access to a TPM emulator using Unix domain 3908 socket based chardev backend. 3909 3910 ``chardev`` specifies the unique ID of a character device backend 3911 that provides connection to the software TPM server. 3912 3913 To create a TPM emulator backend device with chardev socket backend: 3914 3915 :: 3916 3917 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3918ERST 3919 3920DEFHEADING() 3921 3922#endif 3923 3924DEFHEADING(Boot Image or Kernel specific:) 3925SRST 3926There are broadly 4 ways you can boot a system with QEMU. 3927 3928 - specify a firmware and let it control finding a kernel 3929 - specify a firmware and pass a hint to the kernel to boot 3930 - direct kernel image boot 3931 - manually load files into the guest's address space 3932 3933The third method is useful for quickly testing kernels but as there is 3934no firmware to pass configuration information to the kernel the 3935hardware must either be probeable, the kernel built for the exact 3936configuration or passed some configuration data (e.g. a DTB blob) 3937which tells the kernel what drivers it needs. This exact details are 3938often hardware specific. 3939 3940The final method is the most generic way of loading images into the 3941guest address space and used mostly for ``bare metal`` type 3942development where the reset vectors of the processor are taken into 3943account. 3944 3945ERST 3946 3947SRST 3948 3949For x86 machines and some other architectures ``-bios`` will generally 3950do the right thing with whatever it is given. For other machines the 3951more strict ``-pflash`` option needs an image that is sized for the 3952flash device for the given machine type. 3953 3954Please see the :ref:`system-targets-ref` section of the manual for 3955more detailed documentation. 3956 3957ERST 3958 3959DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3960 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3961SRST 3962``-bios file`` 3963 Set the filename for the BIOS. 3964ERST 3965 3966DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3967 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3968SRST 3969``-pflash file`` 3970 Use file as a parallel flash image. 3971ERST 3972 3973SRST 3974 3975The kernel options were designed to work with Linux kernels although 3976other things (like hypervisors) can be packaged up as a kernel 3977executable image. The exact format of a executable image is usually 3978architecture specific. 3979 3980The way in which the kernel is started (what address it is loaded at, 3981what if any information is passed to it via CPU registers, the state 3982of the hardware when it is started, and so on) is also architecture 3983specific. Typically it follows the specification laid down by the 3984Linux kernel for how kernels for that architecture must be started. 3985 3986ERST 3987 3988DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3989 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3990SRST 3991``-kernel bzImage`` 3992 Use bzImage as kernel image. The kernel can be either a Linux kernel 3993 or in multiboot format. 3994ERST 3995 3996DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3997 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3998SRST 3999``-append cmdline`` 4000 Use cmdline as kernel command line 4001ERST 4002 4003DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 4004 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 4005SRST 4006 4007``-initrd file`` 4008 Use file as initial ram disk. 4009 4010``-initrd "file1 arg=foo,file2"`` 4011 This syntax is only available with multiboot. 4012 4013 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4014 first module. Commas can be provided in module parameters by doubling 4015 them on the command line to escape them: 4016 4017``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4018 Multiboot only. Use bzImage as the first module with 4019 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4020 and initrd.img as the second module. 4021 4022ERST 4023 4024DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4025 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4026SRST 4027``-dtb file`` 4028 Use file as a device tree binary (dtb) image and pass it to the 4029 kernel on boot. 4030ERST 4031 4032SRST 4033 4034Finally you can also manually load images directly into the address 4035space of the guest. This is most useful for developers who already 4036know the layout of their guest and take care to ensure something sane 4037will happen when the reset vector executes. 4038 4039The generic loader can be invoked by using the loader device: 4040 4041``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4042 4043there is also the guest loader which operates in a similar way but 4044tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4045the guest image is: 4046 4047``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4048 4049ERST 4050 4051DEFHEADING() 4052 4053DEFHEADING(Debug/Expert options:) 4054 4055DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4056 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4057 " Policy for handling deprecated management interfaces\n" 4058 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4059 " Policy for handling unstable management interfaces\n", 4060 QEMU_ARCH_ALL) 4061SRST 4062``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4063 Set policy for handling deprecated management interfaces (experimental): 4064 4065 ``deprecated-input=accept`` (default) 4066 Accept deprecated commands and arguments 4067 ``deprecated-input=reject`` 4068 Reject deprecated commands and arguments 4069 ``deprecated-input=crash`` 4070 Crash on deprecated commands and arguments 4071 ``deprecated-output=accept`` (default) 4072 Emit deprecated command results and events 4073 ``deprecated-output=hide`` 4074 Suppress deprecated command results and events 4075 4076 Limitation: covers only syntactic aspects of QMP. 4077 4078``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4079 Set policy for handling unstable management interfaces (experimental): 4080 4081 ``unstable-input=accept`` (default) 4082 Accept unstable commands and arguments 4083 ``unstable-input=reject`` 4084 Reject unstable commands and arguments 4085 ``unstable-input=crash`` 4086 Crash on unstable commands and arguments 4087 ``unstable-output=accept`` (default) 4088 Emit unstable command results and events 4089 ``unstable-output=hide`` 4090 Suppress unstable command results and events 4091 4092 Limitation: covers only syntactic aspects of QMP. 4093ERST 4094 4095DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4096 "-fw_cfg [name=]<name>,file=<file>\n" 4097 " add named fw_cfg entry with contents from file\n" 4098 "-fw_cfg [name=]<name>,string=<str>\n" 4099 " add named fw_cfg entry with contents from string\n", 4100 QEMU_ARCH_ALL) 4101SRST 4102``-fw_cfg [name=]name,file=file`` 4103 Add named fw\_cfg entry with contents from file file. 4104 If the filename contains comma, you must double it (for instance, 4105 "file=my,,file" to use file "my,file"). 4106 4107``-fw_cfg [name=]name,string=str`` 4108 Add named fw\_cfg entry with contents from string str. 4109 If the string contains comma, you must double it (for instance, 4110 "string=my,,string" to use file "my,string"). 4111 4112 The terminating NUL character of the contents of str will not be 4113 included as part of the fw\_cfg item data. To insert contents with 4114 embedded NUL characters, you have to use the file parameter. 4115 4116 The fw\_cfg entries are passed by QEMU through to the guest. 4117 4118 Example: 4119 4120 :: 4121 4122 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4123 4124 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4125 from ./my\_blob.bin. 4126ERST 4127 4128DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4129 "-serial dev redirect the serial port to char device 'dev'\n", 4130 QEMU_ARCH_ALL) 4131SRST 4132``-serial dev`` 4133 Redirect the virtual serial port to host character device dev. The 4134 default device is ``vc`` in graphical mode and ``stdio`` in non 4135 graphical mode. 4136 4137 This option can be used several times to simulate up to 4 serial 4138 ports. 4139 4140 Use ``-serial none`` to disable all serial ports. 4141 4142 Available character devices are: 4143 4144 ``vc[:WxH]`` 4145 Virtual console. Optionally, a width and height can be given in 4146 pixel with 4147 4148 :: 4149 4150 vc:800x600 4151 4152 It is also possible to specify width or height in characters: 4153 4154 :: 4155 4156 vc:80Cx24C 4157 4158 ``pty`` 4159 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4160 4161 ``none`` 4162 No device is allocated. 4163 4164 ``null`` 4165 void device 4166 4167 ``chardev:id`` 4168 Use a named character device defined with the ``-chardev`` 4169 option. 4170 4171 ``/dev/XXX`` 4172 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4173 port parameters are set according to the emulated ones. 4174 4175 ``/dev/parportN`` 4176 [Linux only, parallel port only] Use host parallel port N. 4177 Currently SPP and EPP parallel port features can be used. 4178 4179 ``file:filename`` 4180 Write output to filename. No character can be read. 4181 4182 ``stdio`` 4183 [Unix only] standard input/output 4184 4185 ``pipe:filename`` 4186 name pipe filename 4187 4188 ``COMn`` 4189 [Windows only] Use host serial port n 4190 4191 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4192 This implements UDP Net Console. When remote\_host or src\_ip 4193 are not specified they default to ``0.0.0.0``. When not using a 4194 specified src\_port a random port is automatically chosen. 4195 4196 If you just want a simple readonly console you can use 4197 ``netcat`` or ``nc``, by starting QEMU with: 4198 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4199 QEMU writes something to that port it will appear in the 4200 netconsole session. 4201 4202 If you plan to send characters back via netconsole or you want 4203 to stop and start QEMU a lot of times, you should have QEMU use 4204 the same source port each time by using something like ``-serial 4205 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4206 version of netcat which can listen to a TCP port and send and 4207 receive characters via udp. If you have a patched version of 4208 netcat which activates telnet remote echo and single char 4209 transfer, then you can use the following options to set up a 4210 netcat redirector to allow telnet on port 5555 to access the 4211 QEMU port. 4212 4213 ``QEMU Options:`` 4214 -serial udp::4555@:4556 4215 4216 ``netcat options:`` 4217 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4218 4219 ``telnet options:`` 4220 localhost 5555 4221 4222 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4223 The TCP Net Console has two modes of operation. It can send the 4224 serial I/O to a location or wait for a connection from a 4225 location. By default the TCP Net Console is sent to host at the 4226 port. If you use the ``server=on`` option QEMU will wait for a client 4227 socket application to connect to the port before continuing, 4228 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4229 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4230 option only applies if ``server=no`` is set, if the connection goes 4231 down it will attempt to reconnect at the given interval. If host 4232 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4233 time is accepted. You can use ``telnet=on`` to connect to the 4234 corresponding character device. 4235 4236 ``Example to send tcp console to 192.168.0.2 port 4444`` 4237 -serial tcp:192.168.0.2:4444 4238 4239 ``Example to listen and wait on port 4444 for connection`` 4240 -serial tcp::4444,server=on 4241 4242 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4243 -serial tcp:192.168.0.100:4444,server=on,wait=off 4244 4245 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4246 The telnet protocol is used instead of raw tcp sockets. The 4247 options work the same as if you had specified ``-serial tcp``. 4248 The difference is that the port acts like a telnet server or 4249 client using telnet option negotiation. This will also allow you 4250 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4251 supports sending the break sequence. Typically in unix telnet 4252 you do it with Control-] and then type "send break" followed by 4253 pressing the enter key. 4254 4255 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4256 The WebSocket protocol is used instead of raw tcp socket. The 4257 port acts as a WebSocket server. Client mode is not supported. 4258 4259 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4260 A unix domain socket is used instead of a tcp socket. The option 4261 works the same as if you had specified ``-serial tcp`` except 4262 the unix domain socket path is used for connections. 4263 4264 ``mon:dev_string`` 4265 This is a special option to allow the monitor to be multiplexed 4266 onto another serial port. The monitor is accessed with key 4267 sequence of Control-a and then pressing c. dev\_string should be 4268 any one of the serial devices specified above. An example to 4269 multiplex the monitor onto a telnet server listening on port 4270 4444 would be: 4271 4272 ``-serial mon:telnet::4444,server=on,wait=off`` 4273 4274 When the monitor is multiplexed to stdio in this way, Ctrl+C 4275 will not terminate QEMU any more but will be passed to the guest 4276 instead. 4277 4278 ``braille`` 4279 Braille device. This will use BrlAPI to display the braille 4280 output on a real or fake device. 4281 4282 ``msmouse`` 4283 Three button serial mouse. Configure the guest to use Microsoft 4284 protocol. 4285ERST 4286 4287DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4288 "-parallel dev redirect the parallel port to char device 'dev'\n", 4289 QEMU_ARCH_ALL) 4290SRST 4291``-parallel dev`` 4292 Redirect the virtual parallel port to host device dev (same devices 4293 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4294 to use hardware devices connected on the corresponding host parallel 4295 port. 4296 4297 This option can be used several times to simulate up to 3 parallel 4298 ports. 4299 4300 Use ``-parallel none`` to disable all parallel ports. 4301ERST 4302 4303DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4304 "-monitor dev redirect the monitor to char device 'dev'\n", 4305 QEMU_ARCH_ALL) 4306SRST 4307``-monitor dev`` 4308 Redirect the monitor to host device dev (same devices as the serial 4309 port). The default device is ``vc`` in graphical mode and ``stdio`` 4310 in non graphical mode. Use ``-monitor none`` to disable the default 4311 monitor. 4312ERST 4313DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4314 "-qmp dev like -monitor but opens in 'control' mode\n", 4315 QEMU_ARCH_ALL) 4316SRST 4317``-qmp dev`` 4318 Like ``-monitor`` but opens in 'control' mode. For example, to make 4319 QMP available on localhost port 4444:: 4320 4321 -qmp tcp:localhost:4444,server=on,wait=off 4322 4323 Not all options are configurable via this syntax; for maximum 4324 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4325 4326ERST 4327DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4328 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4329 QEMU_ARCH_ALL) 4330SRST 4331``-qmp-pretty dev`` 4332 Like ``-qmp`` but uses pretty JSON formatting. 4333ERST 4334 4335DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4336 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4337SRST 4338``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4339 Set up a monitor connected to the chardev ``name``. 4340 QEMU supports two monitors: the Human Monitor Protocol 4341 (HMP; for human interaction), and the QEMU Monitor Protocol 4342 (QMP; a JSON RPC-style protocol). 4343 The default is HMP; ``mode=control`` selects QMP instead. 4344 ``pretty`` is only valid when ``mode=control``, 4345 turning on JSON pretty printing to ease 4346 human reading and debugging. 4347 4348 For example:: 4349 4350 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4351 -mon chardev=mon1,mode=control,pretty=on 4352 4353 enables the QMP monitor on localhost port 4444 with pretty-printing. 4354ERST 4355 4356DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4357 "-debugcon dev redirect the debug console to char device 'dev'\n", 4358 QEMU_ARCH_ALL) 4359SRST 4360``-debugcon dev`` 4361 Redirect the debug console to host device dev (same devices as the 4362 serial port). The debug console is an I/O port which is typically 4363 port 0xe9; writing to that I/O port sends output to this device. The 4364 default device is ``vc`` in graphical mode and ``stdio`` in non 4365 graphical mode. 4366ERST 4367 4368DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4369 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4370SRST 4371``-pidfile file`` 4372 Store the QEMU process PID in file. It is useful if you launch QEMU 4373 from a script. 4374ERST 4375 4376DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4377 "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL) 4378SRST 4379``-singlestep`` 4380 This is a deprecated synonym for the TCG accelerator property 4381 ``one-insn-per-tb``. 4382ERST 4383 4384DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4385 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4386 QEMU_ARCH_ALL) 4387SRST 4388``--preconfig`` 4389 Pause QEMU for interactive configuration before the machine is 4390 created, which allows querying and configuring properties that will 4391 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4392 exit the preconfig state and move to the next state (i.e. run guest 4393 if -S isn't used or pause the second time if -S is used). This 4394 option is experimental. 4395ERST 4396 4397DEF("S", 0, QEMU_OPTION_S, \ 4398 "-S freeze CPU at startup (use 'c' to start execution)\n", 4399 QEMU_ARCH_ALL) 4400SRST 4401``-S`` 4402 Do not start CPU at startup (you must type 'c' in the monitor). 4403ERST 4404 4405DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4406 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4407 " run qemu with overcommit hints\n" 4408 " mem-lock=on|off controls memory lock support (default: off)\n" 4409 " cpu-pm=on|off controls cpu power management (default: off)\n", 4410 QEMU_ARCH_ALL) 4411SRST 4412``-overcommit mem-lock=on|off`` 4413 \ 4414``-overcommit cpu-pm=on|off`` 4415 Run qemu with hints about host resource overcommit. The default is 4416 to assume that host overcommits all resources. 4417 4418 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4419 (disabled by default). This works when host memory is not 4420 overcommitted and reduces the worst-case latency for guest. 4421 4422 Guest ability to manage power state of host cpus (increasing latency 4423 for other processes on the same host cpu, but decreasing latency for 4424 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4425 works best when host CPU is not overcommitted. When used, host 4426 estimates of CPU cycle and power utilization will be incorrect, not 4427 taking into account guest idle time. 4428ERST 4429 4430DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4431 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4432 " the guest without waiting for gdb to connect; use -S too\n" 4433 " if you want it to not start execution.)\n", 4434 QEMU_ARCH_ALL) 4435SRST 4436``-gdb dev`` 4437 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4438 in the System Emulation Users Guide). Note that this option does not pause QEMU 4439 execution -- if you want QEMU to not start the guest until you 4440 connect with gdb and issue a ``continue`` command, you will need to 4441 also pass the ``-S`` option to QEMU. 4442 4443 The most usual configuration is to listen on a local TCP socket:: 4444 4445 -gdb tcp::3117 4446 4447 but you can specify other backends; UDP, pseudo TTY, or even stdio 4448 are all reasonable use cases. For example, a stdio connection 4449 allows you to start QEMU from within gdb and establish the 4450 connection via a pipe: 4451 4452 .. parsed-literal:: 4453 4454 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4455ERST 4456 4457DEF("s", 0, QEMU_OPTION_s, \ 4458 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4459 QEMU_ARCH_ALL) 4460SRST 4461``-s`` 4462 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4463 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4464ERST 4465 4466DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4467 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4468 QEMU_ARCH_ALL) 4469SRST 4470``-d item1[,...]`` 4471 Enable logging of specified items. Use '-d help' for a list of log 4472 items. 4473ERST 4474 4475DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4476 "-D logfile output log to logfile (default stderr)\n", 4477 QEMU_ARCH_ALL) 4478SRST 4479``-D logfile`` 4480 Output log in logfile instead of to stderr 4481ERST 4482 4483DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4484 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4485 QEMU_ARCH_ALL) 4486SRST 4487``-dfilter range1[,...]`` 4488 Filter debug output to that relevant to a range of target addresses. 4489 The filter spec can be either start+size, start-size or start..end 4490 where start end and size are the addresses and sizes required. For 4491 example: 4492 4493 :: 4494 4495 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4496 4497 Will dump output for any code in the 0x1000 sized block starting at 4498 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4499 another 0x1000 sized block starting at 0xffffffc00005f000. 4500ERST 4501 4502DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4503 "-seed number seed the pseudo-random number generator\n", 4504 QEMU_ARCH_ALL) 4505SRST 4506``-seed number`` 4507 Force the guest to use a deterministic pseudo-random number 4508 generator, seeded with number. This does not affect crypto routines 4509 within the host. 4510ERST 4511 4512DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4513 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4514 QEMU_ARCH_ALL) 4515SRST 4516``-L path`` 4517 Set the directory for the BIOS, VGA BIOS and keymaps. 4518 4519 To list all the data directories, use ``-L help``. 4520ERST 4521 4522DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4523 "-enable-kvm enable KVM full virtualization support\n", 4524 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4525 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4526SRST 4527``-enable-kvm`` 4528 Enable KVM full virtualization support. This option is only 4529 available if KVM support is enabled when compiling. 4530ERST 4531 4532DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4533 "-xen-domid id specify xen guest domain id\n", 4534 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4535DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4536 "-xen-attach attach to existing xen domain\n" 4537 " libxl will use this when starting QEMU\n", 4538 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4539DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4540 "-xen-domid-restrict restrict set of available xen operations\n" 4541 " to specified domain id. (Does not affect\n" 4542 " xenpv machine type).\n", 4543 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4544SRST 4545``-xen-domid id`` 4546 Specify xen guest domain id (XEN only). 4547 4548``-xen-attach`` 4549 Attach to existing xen domain. libxl will use this when starting 4550 QEMU (XEN only). Restrict set of available xen operations to 4551 specified domain id (XEN only). 4552ERST 4553 4554DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4555 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4556SRST 4557``-no-reboot`` 4558 Exit instead of rebooting. 4559ERST 4560 4561DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4562 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4563SRST 4564``-no-shutdown`` 4565 Don't exit QEMU on guest shutdown, but instead only stop the 4566 emulation. This allows for instance switching to monitor to commit 4567 changes to the disk image. 4568ERST 4569 4570DEF("action", HAS_ARG, QEMU_OPTION_action, 4571 "-action reboot=reset|shutdown\n" 4572 " action when guest reboots [default=reset]\n" 4573 "-action shutdown=poweroff|pause\n" 4574 " action when guest shuts down [default=poweroff]\n" 4575 "-action panic=pause|shutdown|exit-failure|none\n" 4576 " action when guest panics [default=shutdown]\n" 4577 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4578 " action when watchdog fires [default=reset]\n", 4579 QEMU_ARCH_ALL) 4580SRST 4581``-action event=action`` 4582 The action parameter serves to modify QEMU's default behavior when 4583 certain guest events occur. It provides a generic method for specifying the 4584 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4585 parameters. 4586 4587 Examples: 4588 4589 ``-action panic=none`` 4590 ``-action reboot=shutdown,shutdown=pause`` 4591 ``-device i6300esb -action watchdog=pause`` 4592 4593ERST 4594 4595DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4596 "-loadvm [tag|id]\n" \ 4597 " start right away with a saved state (loadvm in monitor)\n", 4598 QEMU_ARCH_ALL) 4599SRST 4600``-loadvm file`` 4601 Start right away with a saved state (``loadvm`` in monitor) 4602ERST 4603 4604#ifndef _WIN32 4605DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4606 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4607#endif 4608SRST 4609``-daemonize`` 4610 Daemonize the QEMU process after initialization. QEMU will not 4611 detach from standard IO until it is ready to receive connections on 4612 any of its devices. This option is a useful way for external 4613 programs to launch QEMU without having to cope with initialization 4614 race conditions. 4615ERST 4616 4617DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4618 "-option-rom rom load a file, rom, into the option ROM space\n", 4619 QEMU_ARCH_ALL) 4620SRST 4621``-option-rom file`` 4622 Load the contents of file as an option ROM. This option is useful to 4623 load things like EtherBoot. 4624ERST 4625 4626DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4627 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4628 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4629 QEMU_ARCH_ALL) 4630 4631SRST 4632``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4633 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4634 the current UTC or local time, respectively. ``localtime`` is 4635 required for correct date in MS-DOS or Windows. To start at a 4636 specific point in time, provide datetime in the format 4637 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4638 4639 By default the RTC is driven by the host system time. This allows 4640 using of the RTC as accurate reference clock inside the guest, 4641 specifically if the host time is smoothly following an accurate 4642 external reference clock, e.g. via NTP. If you want to isolate the 4643 guest time from the host, you can set ``clock`` to ``rt`` instead, 4644 which provides a host monotonic clock if host support it. To even 4645 prevent the RTC from progressing during suspension, you can set 4646 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4647 recommended especially in icount mode in order to preserve 4648 determinism; however, note that in icount mode the speed of the 4649 virtual clock is variable and can in general differ from the host 4650 clock. 4651 4652 Enable ``driftfix`` (i386 targets only) if you experience time drift 4653 problems, specifically with Windows' ACPI HAL. This option will try 4654 to figure out how many timer interrupts were not processed by the 4655 Windows guest and will re-inject them. 4656ERST 4657 4658DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4659 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4660 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4661 " instruction, enable aligning the host and virtual clocks\n" \ 4662 " or disable real time cpu sleeping, and optionally enable\n" \ 4663 " record-and-replay mode\n", QEMU_ARCH_ALL) 4664SRST 4665``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4666 Enable virtual instruction counter. The virtual cpu will execute one 4667 instruction every 2^N ns of virtual time. If ``auto`` is specified 4668 then the virtual cpu speed will be automatically adjusted to keep 4669 virtual time within a few seconds of real time. 4670 4671 Note that while this option can give deterministic behavior, it does 4672 not provide cycle accurate emulation. Modern CPUs contain 4673 superscalar out of order cores with complex cache hierarchies. The 4674 number of instructions executed often has little or no correlation 4675 with actual performance. 4676 4677 When the virtual cpu is sleeping, the virtual time will advance at 4678 default speed unless ``sleep=on`` is specified. With 4679 ``sleep=on``, the virtual time will jump to the next timer 4680 deadline instantly whenever the virtual cpu goes to sleep mode and 4681 will not advance if no timer is enabled. This behavior gives 4682 deterministic execution times from the guest point of view. 4683 The default if icount is enabled is ``sleep=off``. 4684 ``sleep=on`` cannot be used together with either ``shift=auto`` 4685 or ``align=on``. 4686 4687 ``align=on`` will activate the delay algorithm which will try to 4688 synchronise the host clock and the virtual clock. The goal is to 4689 have a guest running at the real frequency imposed by the shift 4690 option. Whenever the guest clock is behind the host clock and if 4691 ``align=on`` is specified then we print a message to the user to 4692 inform about the delay. Currently this option does not work when 4693 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4694 shift values for which the guest clock runs ahead of the host clock. 4695 Typically this happens when the shift value is high (how high 4696 depends on the host machine). The default if icount is enabled 4697 is ``align=off``. 4698 4699 When the ``rr`` option is specified deterministic record/replay is 4700 enabled. The ``rrfile=`` option must also be provided to 4701 specify the path to the replay log. In record mode data is written 4702 to this file, and in replay mode it is read back. 4703 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4704 name. In record mode, a new VM snapshot with the given name is created 4705 at the start of execution recording. In replay mode this option 4706 specifies the snapshot name used to load the initial VM state. 4707ERST 4708 4709DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4710 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4711 " action when watchdog fires [default=reset]\n", 4712 QEMU_ARCH_ALL) 4713SRST 4714``-watchdog-action action`` 4715 The action controls what QEMU will do when the watchdog timer 4716 expires. The default is ``reset`` (forcefully reset the guest). 4717 Other possible actions are: ``shutdown`` (attempt to gracefully 4718 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4719 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4720 guest), ``debug`` (print a debug message and continue), or ``none`` 4721 (do nothing). 4722 4723 Note that the ``shutdown`` action requires that the guest responds 4724 to ACPI signals, which it may not be able to do in the sort of 4725 situations where the watchdog would have expired, and thus 4726 ``-watchdog-action shutdown`` is not recommended for production use. 4727 4728 Examples: 4729 4730 ``-device i6300esb -watchdog-action pause`` 4731 4732ERST 4733 4734DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4735 "-echr chr set terminal escape character instead of ctrl-a\n", 4736 QEMU_ARCH_ALL) 4737SRST 4738``-echr numeric_ascii_value`` 4739 Change the escape character used for switching to the monitor when 4740 using monitor and serial sharing. The default is ``0x01`` when using 4741 the ``-nographic`` option. ``0x01`` is equal to pressing 4742 ``Control-a``. You can select a different character from the ascii 4743 control keys where 1 through 26 map to Control-a through Control-z. 4744 For instance you could use the either of the following to change the 4745 escape character to Control-t. 4746 4747 ``-echr 0x14``; \ ``-echr 20`` 4748 4749ERST 4750 4751DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4752 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4753 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4754 "-incoming unix:socketpath\n" \ 4755 " prepare for incoming migration, listen on\n" \ 4756 " specified protocol and socket address\n" \ 4757 "-incoming fd:fd\n" \ 4758 "-incoming file:filename[,offset=offset]\n" \ 4759 "-incoming exec:cmdline\n" \ 4760 " accept incoming migration on given file descriptor\n" \ 4761 " or from given external command\n" \ 4762 "-incoming defer\n" \ 4763 " wait for the URI to be specified via migrate_incoming\n", 4764 QEMU_ARCH_ALL) 4765SRST 4766``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4767 \ 4768``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4769 Prepare for incoming migration, listen on a given tcp port. 4770 4771``-incoming unix:socketpath`` 4772 Prepare for incoming migration, listen on a given unix socket. 4773 4774``-incoming fd:fd`` 4775 Accept incoming migration from a given file descriptor. 4776 4777``-incoming file:filename[,offset=offset]`` 4778 Accept incoming migration from a given file starting at offset. 4779 offset allows the common size suffixes, or a 0x prefix, but not both. 4780 4781``-incoming exec:cmdline`` 4782 Accept incoming migration as an output from specified external 4783 command. 4784 4785``-incoming defer`` 4786 Wait for the URI to be specified via migrate\_incoming. The monitor 4787 can be used to change settings (such as migration parameters) prior 4788 to issuing the migrate\_incoming to allow the migration to begin. 4789ERST 4790 4791DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4792 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4793SRST 4794``-only-migratable`` 4795 Only allow migratable devices. Devices will not be allowed to enter 4796 an unmigratable state. 4797ERST 4798 4799DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4800 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4801SRST 4802``-nodefaults`` 4803 Don't create default devices. Normally, QEMU sets the default 4804 devices like serial port, parallel port, virtual console, monitor 4805 device, VGA adapter, floppy and CD-ROM drive and others. The 4806 ``-nodefaults`` option will disable all those default devices. 4807ERST 4808 4809#ifndef _WIN32 4810DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4811 "-chroot dir chroot to dir just before starting the VM (deprecated)\n", 4812 QEMU_ARCH_ALL) 4813#endif 4814SRST 4815``-chroot dir`` 4816 Deprecated, use '-run-with chroot=...' instead. 4817 Immediately before starting guest execution, chroot to the specified 4818 directory. Especially useful in combination with -runas. 4819ERST 4820 4821#ifndef _WIN32 4822DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4823 "-runas user change to user id user just before starting the VM\n" \ 4824 " user can be numeric uid:gid instead\n", 4825 QEMU_ARCH_ALL) 4826#endif 4827SRST 4828``-runas user`` 4829 Immediately before starting guest execution, drop root privileges, 4830 switching to the specified user. 4831ERST 4832 4833DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4834 "-prom-env variable=value\n" 4835 " set OpenBIOS nvram variables\n", 4836 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4837SRST 4838``-prom-env variable=value`` 4839 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4840 4841 :: 4842 4843 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4844 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4845 4846 :: 4847 4848 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4849 -prom-env 'boot-device=hd:2,\yaboot' \ 4850 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4851ERST 4852DEF("semihosting", 0, QEMU_OPTION_semihosting, 4853 "-semihosting semihosting mode\n", 4854 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4855 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4856SRST 4857``-semihosting`` 4858 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4859 4860 .. warning:: 4861 Note that this allows guest direct access to the host filesystem, so 4862 should only be used with a trusted guest OS. 4863 4864 See the -semihosting-config option documentation for further 4865 information about the facilities this enables. 4866ERST 4867DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4868 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4869 " semihosting configuration\n", 4870QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4871QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4872SRST 4873``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4874 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4875 only). 4876 4877 .. warning:: 4878 Note that this allows guest direct access to the host filesystem, so 4879 should only be used with a trusted guest OS. 4880 4881 ``target=native|gdb|auto`` 4882 Defines where the semihosting calls will be addressed, to QEMU 4883 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4884 means ``gdb`` during debug sessions and ``native`` otherwise. 4885 4886 ``chardev=str1`` 4887 Send the output to a chardev backend output for native or auto 4888 output when not in gdb 4889 4890 ``userspace=on|off`` 4891 Allows code running in guest userspace to access the semihosting 4892 interface. The default is that only privileged guest code can 4893 make semihosting calls. Note that setting ``userspace=on`` should 4894 only be used if all guest code is trusted (for example, in 4895 bare-metal test case code). 4896 4897 ``arg=str1,arg=str2,...`` 4898 Allows the user to pass input arguments, and can be used 4899 multiple times to build up a list. The old-style 4900 ``-kernel``/``-append`` method of passing a command line is 4901 still supported for backward compatibility. If both the 4902 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4903 specified, the former is passed to semihosting as it always 4904 takes precedence. 4905ERST 4906DEF("old-param", 0, QEMU_OPTION_old_param, 4907 "-old-param old param mode\n", QEMU_ARCH_ARM) 4908SRST 4909``-old-param`` 4910 Old param mode (ARM only). 4911ERST 4912 4913DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4914 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4915 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4916 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4917 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4918 " by the kernel, but typically no longer used by modern\n" \ 4919 " C library implementations.\n" \ 4920 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4921 " to elevate privileges using set*uid|gid system calls.\n" \ 4922 " The value 'children' will deny set*uid|gid system calls for\n" \ 4923 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4924 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4925 " blocking *fork and execve\n" \ 4926 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4927 QEMU_ARCH_ALL) 4928SRST 4929``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4930 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4931 filtering and 'off' will disable it. The default is 'off'. 4932 4933 ``obsolete=string`` 4934 Enable Obsolete system calls 4935 4936 ``elevateprivileges=string`` 4937 Disable set\*uid\|gid system calls 4938 4939 ``spawn=string`` 4940 Disable \*fork and execve 4941 4942 ``resourcecontrol=string`` 4943 Disable process affinity and schedular priority 4944ERST 4945 4946DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4947 "-readconfig <file>\n" 4948 " read config file\n", QEMU_ARCH_ALL) 4949SRST 4950``-readconfig file`` 4951 Read device configuration from file. This approach is useful when 4952 you want to spawn QEMU process with many command line options but 4953 you don't want to exceed the command line character limit. 4954ERST 4955 4956DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4957 "-no-user-config\n" 4958 " do not load default user-provided config files at startup\n", 4959 QEMU_ARCH_ALL) 4960SRST 4961``-no-user-config`` 4962 The ``-no-user-config`` option makes QEMU not load any of the 4963 user-provided config files on sysconfdir. 4964ERST 4965 4966DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4967 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4968 " specify tracing options\n", 4969 QEMU_ARCH_ALL) 4970SRST 4971``-trace [[enable=]pattern][,events=file][,file=file]`` 4972 .. include:: ../qemu-option-trace.rst.inc 4973 4974ERST 4975DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4976 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4977 " load a plugin\n", 4978 QEMU_ARCH_ALL) 4979SRST 4980``-plugin file=file[,argname=argvalue]`` 4981 Load a plugin. 4982 4983 ``file=file`` 4984 Load the given plugin from a shared library file. 4985 4986 ``argname=argvalue`` 4987 Argument passed to the plugin. (Can be given multiple times.) 4988ERST 4989 4990HXCOMM Internal use 4991DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4992DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4993 4994#ifdef __linux__ 4995DEF("async-teardown", 0, QEMU_OPTION_asyncteardown, 4996 "-async-teardown enable asynchronous teardown\n", 4997 QEMU_ARCH_ALL) 4998SRST 4999``-async-teardown`` 5000 This option is deprecated and should no longer be used. The new option 5001 ``-run-with async-teardown=on`` is a replacement. 5002ERST 5003#endif 5004#ifdef CONFIG_POSIX 5005DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 5006 "-run-with [async-teardown=on|off][,chroot=dir]\n" 5007 " Set miscellaneous QEMU process lifecycle options:\n" 5008 " async-teardown=on enables asynchronous teardown (Linux only)\n" 5009 " chroot=dir chroot to dir just before starting the VM\n", 5010 QEMU_ARCH_ALL) 5011SRST 5012``-run-with [async-teardown=on|off][,chroot=dir]`` 5013 Set QEMU process lifecycle options. 5014 5015 ``async-teardown=on`` enables asynchronous teardown. A new process called 5016 "cleanup/<QEMU_PID>" will be created at startup sharing the address 5017 space with the main QEMU process, using clone. It will wait for the 5018 main QEMU process to terminate completely, and then exit. This allows 5019 QEMU to terminate very quickly even if the guest was huge, leaving the 5020 teardown of the address space to the cleanup process. Since the cleanup 5021 process shares the same cgroups as the main QEMU process, accounting is 5022 performed correctly. This only works if the cleanup process is not 5023 forcefully killed with SIGKILL before the main QEMU process has 5024 terminated completely. 5025 5026 ``chroot=dir`` can be used for doing a chroot to the specified directory 5027 immediately before starting the guest execution. This is especially useful 5028 in combination with -runas. 5029ERST 5030#endif 5031 5032DEF("msg", HAS_ARG, QEMU_OPTION_msg, 5033 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 5034 " control error message format\n" 5035 " timestamp=on enables timestamps (default: off)\n" 5036 " guest-name=on enables guest name prefix but only if\n" 5037 " -name guest option is set (default: off)\n", 5038 QEMU_ARCH_ALL) 5039SRST 5040``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 5041 Control error message format. 5042 5043 ``timestamp=on|off`` 5044 Prefix messages with a timestamp. Default is off. 5045 5046 ``guest-name=on|off`` 5047 Prefix messages with guest name but only if -name guest option is set 5048 otherwise the option is ignored. Default is off. 5049ERST 5050 5051DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5052 "-dump-vmstate <file>\n" 5053 " Output vmstate information in JSON format to file.\n" 5054 " Use the scripts/vmstate-static-checker.py file to\n" 5055 " check for possible regressions in migration code\n" 5056 " by comparing two such vmstate dumps.\n", 5057 QEMU_ARCH_ALL) 5058SRST 5059``-dump-vmstate file`` 5060 Dump json-encoded vmstate information for current machine type to 5061 file in file 5062ERST 5063 5064DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5065 "-enable-sync-profile\n" 5066 " enable synchronization profiling\n", 5067 QEMU_ARCH_ALL) 5068SRST 5069``-enable-sync-profile`` 5070 Enable synchronization profiling. 5071ERST 5072 5073#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5074DEF("perfmap", 0, QEMU_OPTION_perfmap, 5075 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5076 QEMU_ARCH_ALL) 5077SRST 5078``-perfmap`` 5079 Generate a map file for Linux perf tools that will allow basic profiling 5080 information to be broken down into basic blocks. 5081ERST 5082 5083DEF("jitdump", 0, QEMU_OPTION_jitdump, 5084 "-jitdump generate a jit-${pid}.dump file for perf\n", 5085 QEMU_ARCH_ALL) 5086SRST 5087``-jitdump`` 5088 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5089 names, line numbers and JITted code. 5090ERST 5091#endif 5092 5093DEFHEADING() 5094 5095DEFHEADING(Generic object creation:) 5096 5097DEF("object", HAS_ARG, QEMU_OPTION_object, 5098 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5099 " create a new object of type TYPENAME setting properties\n" 5100 " in the order they are specified. Note that the 'id'\n" 5101 " property must be set. These objects are placed in the\n" 5102 " '/objects' path.\n", 5103 QEMU_ARCH_ALL) 5104SRST 5105``-object typename[,prop1=value1,...]`` 5106 Create a new object of type typename setting properties in the order 5107 they are specified. Note that the 'id' property must be set. These 5108 objects are placed in the '/objects' path. 5109 5110 ``-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`` 5111 Creates a memory file backend object, which can be used to back 5112 the guest RAM with huge pages. 5113 5114 The ``id`` parameter is a unique ID that will be used to 5115 reference this memory region in other parameters, e.g. ``-numa``, 5116 ``-device nvdimm``, etc. 5117 5118 The ``size`` option provides the size of the memory region, and 5119 accepts common suffixes, e.g. ``500M``. 5120 5121 The ``mem-path`` provides the path to either a shared memory or 5122 huge page filesystem mount. 5123 5124 The ``share`` boolean option determines whether the memory 5125 region is marked as private to QEMU, or shared. The latter 5126 allows a co-operating external process to access the QEMU memory 5127 region. 5128 5129 The ``share`` is also required for pvrdma devices due to 5130 limitations in the RDMA API provided by Linux. 5131 5132 Setting share=on might affect the ability to configure NUMA 5133 bindings for the memory backend under some circumstances, see 5134 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5135 source tree for additional details. 5136 5137 Setting the ``discard-data`` boolean option to on indicates that 5138 file contents can be destroyed when QEMU exits, to avoid 5139 unnecessarily flushing data to the backing file. Note that 5140 ``discard-data`` is only an optimization, and QEMU might not 5141 discard file contents if it aborts unexpectedly or is terminated 5142 using SIGKILL. 5143 5144 The ``merge`` boolean option enables memory merge, also known as 5145 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5146 the pages for memory deduplication. 5147 5148 Setting the ``dump`` boolean option to off excludes the memory 5149 from core dumps. This feature is also known as MADV\_DONTDUMP. 5150 5151 The ``prealloc`` boolean option enables memory preallocation. 5152 5153 The ``host-nodes`` option binds the memory range to a list of 5154 NUMA host nodes. 5155 5156 The ``policy`` option sets the NUMA policy to one of the 5157 following values: 5158 5159 ``default`` 5160 default host policy 5161 5162 ``preferred`` 5163 prefer the given host node list for allocation 5164 5165 ``bind`` 5166 restrict memory allocation to the given host node list 5167 5168 ``interleave`` 5169 interleave memory allocations across the given host node 5170 list 5171 5172 The ``align`` option specifies the base address alignment when 5173 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5174 ``2M``. Some backend store specified by ``mem-path`` requires an 5175 alignment different than the default one used by QEMU, eg the 5176 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5177 such cases, users can specify the required alignment via this 5178 option. 5179 5180 The ``offset`` option specifies the offset into the target file 5181 that the region starts at. You can use this parameter to back 5182 multiple regions with a single file. 5183 5184 The ``pmem`` option specifies whether the backing file specified 5185 by ``mem-path`` is in host persistent memory that can be 5186 accessed using the SNIA NVM programming model (e.g. Intel 5187 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5188 operations to guarantee the persistence of its own writes to 5189 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5190 migration). Also, we will map the backend-file with MAP\_SYNC 5191 flag, which ensures the file metadata is in sync for 5192 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5193 requires support from both the host kernel (since Linux kernel 5194 4.15) and the filesystem of ``mem-path`` mounted with DAX 5195 option. 5196 5197 The ``readonly`` option specifies whether the backing file is opened 5198 read-only or read-write (default). 5199 5200 The ``rom`` option specifies whether to create Read Only Memory 5201 (ROM) that cannot be modified by the VM. Any write attempts to such 5202 ROM will be denied. Most use cases want proper RAM instead of ROM. 5203 However, selected use cases, like R/O NVDIMMs, can benefit from 5204 ROM. If set to ``on``, create ROM; if set to ``off``, create 5205 writable RAM; if set to ``auto`` (default), the value of the 5206 ``readonly`` option is used. This option is primarily helpful when 5207 we want to have writable RAM in configurations that would 5208 traditionally create ROM before the ``rom`` option was introduced: 5209 VM templating, where we want to open a file readonly 5210 (``readonly=on``) and mark the memory to be private for QEMU 5211 (``share=off``). For this use case, we need writable RAM instead 5212 of ROM, and want to also set ``rom=off``. 5213 5214 ``-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`` 5215 Creates a memory backend object, which can be used to back the 5216 guest RAM. Memory backend objects offer more control than the 5217 ``-m`` option that is traditionally used to define guest RAM. 5218 Please refer to ``memory-backend-file`` for a description of the 5219 options. 5220 5221 ``-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`` 5222 Creates an anonymous memory file backend object, which allows 5223 QEMU to share the memory with an external process (e.g. when 5224 using vhost-user). The memory is allocated with memfd and 5225 optional sealing. (Linux only) 5226 5227 The ``seal`` option creates a sealed-file, that will block 5228 further resizing the memory ('on' by default). 5229 5230 The ``hugetlb`` option specify the file to be created resides in 5231 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5232 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5233 the hugetlb page size on systems that support multiple hugetlb 5234 page sizes (it must be a power of 2 value supported by the 5235 system). 5236 5237 In some versions of Linux, the ``hugetlb`` option is 5238 incompatible with the ``seal`` option (requires at least Linux 5239 4.16). 5240 5241 Please refer to ``memory-backend-file`` for a description of the 5242 other options. 5243 5244 The ``share`` boolean option is on by default with memfd. 5245 5246 ``-object iommufd,id=id[,fd=fd]`` 5247 Creates an iommufd backend which allows control of DMA mapping 5248 through the ``/dev/iommu`` device. 5249 5250 The ``id`` parameter is a unique ID which frontends (such as 5251 vfio-pci of vdpa) will use to connect with the iommufd backend. 5252 5253 The ``fd`` parameter is an optional pre-opened file descriptor 5254 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5255 across all subsystems, bringing the benefit of centralized 5256 reference counting. 5257 5258 ``-object rng-builtin,id=id`` 5259 Creates a random number generator backend which obtains entropy 5260 from QEMU builtin functions. The ``id`` parameter is a unique ID 5261 that will be used to reference this entropy backend from the 5262 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5263 uses this RNG backend. 5264 5265 ``-object rng-random,id=id,filename=/dev/random`` 5266 Creates a random number generator backend which obtains entropy 5267 from a device on the host. The ``id`` parameter is a unique ID 5268 that will be used to reference this entropy backend from the 5269 ``virtio-rng`` device. The ``filename`` parameter specifies 5270 which file to obtain entropy from and if omitted defaults to 5271 ``/dev/urandom``. 5272 5273 ``-object rng-egd,id=id,chardev=chardevid`` 5274 Creates a random number generator backend which obtains entropy 5275 from an external daemon running on the host. The ``id`` 5276 parameter is a unique ID that will be used to reference this 5277 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5278 parameter is the unique ID of a character device backend that 5279 provides the connection to the RNG daemon. 5280 5281 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5282 Creates a TLS anonymous credentials object, which can be used to 5283 provide TLS support on network backends. The ``id`` parameter is 5284 a unique ID which network backends will use to access the 5285 credentials. The ``endpoint`` is either ``server`` or ``client`` 5286 depending on whether the QEMU network backend that uses the 5287 credentials will be acting as a client or as a server. If 5288 ``verify-peer`` is enabled (the default) then once the handshake 5289 is completed, the peer credentials will be verified, though this 5290 is a no-op for anonymous credentials. 5291 5292 The dir parameter tells QEMU where to find the credential files. 5293 For server endpoints, this directory may contain a file 5294 dh-params.pem providing diffie-hellman parameters to use for the 5295 TLS server. If the file is missing, QEMU will generate a set of 5296 DH parameters at startup. This is a computationally expensive 5297 operation that consumes random pool entropy, so it is 5298 recommended that a persistent set of parameters be generated 5299 upfront and saved. 5300 5301 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5302 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5303 can be used to provide TLS support on network backends. The 5304 ``id`` parameter is a unique ID which network backends will use 5305 to access the credentials. The ``endpoint`` is either ``server`` 5306 or ``client`` depending on whether the QEMU network backend that 5307 uses the credentials will be acting as a client or as a server. 5308 For clients only, ``username`` is the username which will be 5309 sent to the server. If omitted it defaults to "qemu". 5310 5311 The dir parameter tells QEMU where to find the keys file. It is 5312 called "dir/keys.psk" and contains "username:key" pairs. This 5313 file can most easily be created using the GnuTLS ``psktool`` 5314 program. 5315 5316 For server endpoints, dir may also contain a file dh-params.pem 5317 providing diffie-hellman parameters to use for the TLS server. 5318 If the file is missing, QEMU will generate a set of DH 5319 parameters at startup. This is a computationally expensive 5320 operation that consumes random pool entropy, so it is 5321 recommended that a persistent set of parameters be generated up 5322 front and saved. 5323 5324 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5325 Creates a TLS anonymous credentials object, which can be used to 5326 provide TLS support on network backends. The ``id`` parameter is 5327 a unique ID which network backends will use to access the 5328 credentials. The ``endpoint`` is either ``server`` or ``client`` 5329 depending on whether the QEMU network backend that uses the 5330 credentials will be acting as a client or as a server. If 5331 ``verify-peer`` is enabled (the default) then once the handshake 5332 is completed, the peer credentials will be verified. With x509 5333 certificates, this implies that the clients must be provided 5334 with valid client certificates too. 5335 5336 The dir parameter tells QEMU where to find the credential files. 5337 For server endpoints, this directory may contain a file 5338 dh-params.pem providing diffie-hellman parameters to use for the 5339 TLS server. If the file is missing, QEMU will generate a set of 5340 DH parameters at startup. This is a computationally expensive 5341 operation that consumes random pool entropy, so it is 5342 recommended that a persistent set of parameters be generated 5343 upfront and saved. 5344 5345 For x509 certificate credentials the directory will contain 5346 further files providing the x509 certificates. The certificates 5347 must be stored in PEM format, in filenames ca-cert.pem, 5348 ca-crl.pem (optional), server-cert.pem (only servers), 5349 server-key.pem (only servers), client-cert.pem (only clients), 5350 and client-key.pem (only clients). 5351 5352 For the server-key.pem and client-key.pem files which contain 5353 sensitive private keys, it is possible to use an encrypted 5354 version by providing the passwordid parameter. This provides the 5355 ID of a previously created ``secret`` object containing the 5356 password for decryption. 5357 5358 The priority parameter allows to override the global default 5359 priority used by gnutls. This can be useful if the system 5360 administrator needs to use a weaker set of crypto priorities for 5361 QEMU without potentially forcing the weakness onto all 5362 applications. Or conversely if one wants wants a stronger 5363 default for QEMU than for all other applications, they can do 5364 this through this parameter. Its format is a gnutls priority 5365 string as described at 5366 https://gnutls.org/manual/html_node/Priority-Strings.html. 5367 5368 ``-object tls-cipher-suites,id=id,priority=priority`` 5369 Creates a TLS cipher suites object, which can be used to control 5370 the TLS cipher/protocol algorithms that applications are permitted 5371 to use. 5372 5373 The ``id`` parameter is a unique ID which frontends will use to 5374 access the ordered list of permitted TLS cipher suites from the 5375 host. 5376 5377 The ``priority`` parameter allows to override the global default 5378 priority used by gnutls. This can be useful if the system 5379 administrator needs to use a weaker set of crypto priorities for 5380 QEMU without potentially forcing the weakness onto all 5381 applications. Or conversely if one wants wants a stronger 5382 default for QEMU than for all other applications, they can do 5383 this through this parameter. Its format is a gnutls priority 5384 string as described at 5385 https://gnutls.org/manual/html_node/Priority-Strings.html. 5386 5387 An example of use of this object is to control UEFI HTTPS Boot. 5388 The tls-cipher-suites object exposes the ordered list of permitted 5389 TLS cipher suites from the host side to the guest firmware, via 5390 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5391 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5392 guest-side TLS. 5393 5394 In the following example, the priority at which the host-side policy 5395 is retrieved is given by the ``priority`` property. 5396 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5397 refer to /etc/crypto-policies/back-ends/gnutls.config. 5398 5399 .. parsed-literal:: 5400 5401 # |qemu_system| \\ 5402 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5403 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5404 5405 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5406 Interval t can't be 0, this filter batches the packet delivery: 5407 all packets arriving in a given interval on netdev netdevid are 5408 delayed until the end of the interval. Interval is in 5409 microseconds. ``status`` is optional that indicate whether the 5410 netfilter is on (enabled) or off (disabled), the default status 5411 for netfilter will be 'on'. 5412 5413 queue all\|rx\|tx is an option that can be applied to any 5414 netfilter. 5415 5416 ``all``: the filter is attached both to the receive and the 5417 transmit queue of the netdev (default). 5418 5419 ``rx``: the filter is attached to the receive queue of the 5420 netdev, where it will receive packets sent to the netdev. 5421 5422 ``tx``: the filter is attached to the transmit queue of the 5423 netdev, where it will receive packets sent by the netdev. 5424 5425 position head\|tail\|id=<id> is an option to specify where the 5426 filter should be inserted in the filter list. It can be applied 5427 to any netfilter. 5428 5429 ``head``: the filter is inserted at the head of the filter list, 5430 before any existing filters. 5431 5432 ``tail``: the filter is inserted at the tail of the filter list, 5433 behind any existing filters (default). 5434 5435 ``id=<id>``: the filter is inserted before or behind the filter 5436 specified by <id>, see the insert option below. 5437 5438 insert behind\|before is an option to specify where to insert 5439 the new filter relative to the one specified with 5440 position=id=<id>. It can be applied to any netfilter. 5441 5442 ``before``: insert before the specified filter. 5443 5444 ``behind``: insert behind the specified filter (default). 5445 5446 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5447 filter-mirror on netdev netdevid,mirror net packet to 5448 chardevchardevid, if it has the vnet\_hdr\_support flag, 5449 filter-mirror will mirror packet with vnet\_hdr\_len. 5450 5451 ``-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]`` 5452 filter-redirector on netdev netdevid,redirect filter's net 5453 packet to chardev chardevid,and redirect indev's packet to 5454 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5455 will redirect packet with vnet\_hdr\_len. Create a 5456 filter-redirector we need to differ outdev id from indev id, id 5457 can not be the same. we can just use indev or outdev, but at 5458 least one of indev or outdev need to be specified. 5459 5460 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5461 Filter-rewriter is a part of COLO project.It will rewrite tcp 5462 packet to secondary from primary to keep secondary tcp 5463 connection,and rewrite tcp packet to primary from secondary make 5464 tcp packet can be handled by client.if it has the 5465 vnet\_hdr\_support flag, we can parse packet with vnet header. 5466 5467 usage: colo secondary: -object 5468 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5469 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5470 filter-rewriter,id=rew0,netdev=hn0,queue=all 5471 5472 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5473 Dump the network traffic on netdev dev to the file specified by 5474 filename. At most len bytes (64k by default) per packet are 5475 stored. The file format is libpcap, so it can be analyzed with 5476 tools such as tcpdump or Wireshark. 5477 5478 ``-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}]`` 5479 Colo-compare gets packet from primary\_in chardevid and 5480 secondary\_in, then compare whether the payload of primary packet 5481 and secondary packet are the same. If same, it will output 5482 primary packet to out\_dev, else it will notify COLO-framework to do 5483 checkpoint and send primary packet to out\_dev. In order to 5484 improve efficiency, we need to put the task of comparison in 5485 another iothread. If it has the vnet\_hdr\_support flag, 5486 colo compare will send/recv packet with vnet\_hdr\_len. 5487 The compare\_timeout=@var{ms} determines the maximum time of the 5488 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5489 is to set the period of scanning expired primary node network packets. 5490 The max\_queue\_size=@var{size} is to set the max compare queue 5491 size depend on user environment. 5492 If user want to use Xen COLO, need to add the notify\_dev to 5493 notify Xen colo-frame to do checkpoint. 5494 5495 COLO-compare must be used with the help of filter-mirror, 5496 filter-redirector and filter-rewriter. 5497 5498 :: 5499 5500 KVM COLO 5501 5502 primary: 5503 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5504 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5505 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5506 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5507 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5508 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5509 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5510 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5511 -object iothread,id=iothread1 5512 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5513 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5514 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5515 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5516 5517 secondary: 5518 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5519 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5520 -chardev socket,id=red0,host=3.3.3.3,port=9003 5521 -chardev socket,id=red1,host=3.3.3.3,port=9004 5522 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5523 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5524 5525 5526 Xen COLO 5527 5528 primary: 5529 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5530 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5531 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5532 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5533 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5534 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5535 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5536 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5537 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5538 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5539 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5540 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5541 -object iothread,id=iothread1 5542 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5543 5544 secondary: 5545 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5546 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5547 -chardev socket,id=red0,host=3.3.3.3,port=9003 5548 -chardev socket,id=red1,host=3.3.3.3,port=9004 5549 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5550 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5551 5552 If you want to know the detail of above command line, you can 5553 read the colo-compare git log. 5554 5555 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5556 Creates a cryptodev backend which executes crypto operations from 5557 the QEMU cipher APIs. The id parameter is a unique ID that will 5558 be used to reference this cryptodev backend from the 5559 ``virtio-crypto`` device. The queues parameter is optional, 5560 which specify the queue number of cryptodev backend, the default 5561 of queues is 1. 5562 5563 .. parsed-literal:: 5564 5565 # |qemu_system| \\ 5566 [...] \\ 5567 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5568 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5569 [...] 5570 5571 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5572 Creates a vhost-user cryptodev backend, backed by a chardev 5573 chardevid. The id parameter is a unique ID that will be used to 5574 reference this cryptodev backend from the ``virtio-crypto`` 5575 device. The chardev should be a unix domain socket backed one. 5576 The vhost-user uses a specifically defined protocol to pass 5577 vhost ioctl replacement messages to an application on the other 5578 end of the socket. The queues parameter is optional, which 5579 specify the queue number of cryptodev backend for multiqueue 5580 vhost-user, the default of queues is 1. 5581 5582 .. parsed-literal:: 5583 5584 # |qemu_system| \\ 5585 [...] \\ 5586 -chardev socket,id=chardev0,path=/path/to/socket \\ 5587 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5588 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5589 [...] 5590 5591 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5592 \ 5593 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5594 Defines a secret to store a password, encryption key, or some 5595 other sensitive data. The sensitive data can either be passed 5596 directly via the data parameter, or indirectly via the file 5597 parameter. Using the data parameter is insecure unless the 5598 sensitive data is encrypted. 5599 5600 The sensitive data can be provided in raw format (the default), 5601 or base64. When encoded as JSON, the raw format only supports 5602 valid UTF-8 characters, so base64 is recommended for sending 5603 binary data. QEMU will convert from which ever format is 5604 provided to the format it needs internally. eg, an RBD password 5605 can be provided in raw format, even though it will be base64 5606 encoded when passed onto the RBD sever. 5607 5608 For added protection, it is possible to encrypt the data 5609 associated with a secret using the AES-256-CBC cipher. Use of 5610 encryption is indicated by providing the keyid and iv 5611 parameters. The keyid parameter provides the ID of a previously 5612 defined secret that contains the AES-256 decryption key. This 5613 key should be 32-bytes long and be base64 encoded. The iv 5614 parameter provides the random initialization vector used for 5615 encryption of this particular secret and should be a base64 5616 encrypted string of the 16-byte IV. 5617 5618 The simplest (insecure) usage is to provide the secret inline 5619 5620 .. parsed-literal:: 5621 5622 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5623 5624 The simplest secure usage is to provide the secret via a file 5625 5626 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5627 secret,id=sec0,file=mypasswd.txt,format=raw 5628 5629 For greater security, AES-256-CBC should be used. To illustrate 5630 usage, consider the openssl command line tool which can encrypt 5631 the data. Note that when encrypting, the plaintext must be 5632 padded to the cipher block size (32 bytes) using the standard 5633 PKCS#5/6 compatible padding algorithm. 5634 5635 First a master key needs to be created in base64 encoding: 5636 5637 :: 5638 5639 # openssl rand -base64 32 > key.b64 5640 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5641 5642 Each secret to be encrypted needs to have a random 5643 initialization vector generated. These do not need to be kept 5644 secret 5645 5646 :: 5647 5648 # openssl rand -base64 16 > iv.b64 5649 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5650 5651 The secret to be defined can now be encrypted, in this case 5652 we're telling openssl to base64 encode the result, but it could 5653 be left as raw bytes if desired. 5654 5655 :: 5656 5657 # SECRET=$(printf "letmein" | 5658 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5659 5660 When launching QEMU, create a master secret pointing to 5661 ``key.b64`` and specify that to be used to decrypt the user 5662 password. Pass the contents of ``iv.b64`` to the second secret 5663 5664 .. parsed-literal:: 5665 5666 # |qemu_system| \\ 5667 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5668 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5669 data=$SECRET,iv=$(<iv.b64) 5670 5671 ``-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]`` 5672 Create a Secure Encrypted Virtualization (SEV) guest object, 5673 which can be used to provide the guest memory encryption support 5674 on AMD processors. 5675 5676 When memory encryption is enabled, one of the physical address 5677 bit (aka the C-bit) is utilized to mark if a memory page is 5678 protected. The ``cbitpos`` is used to provide the C-bit 5679 position. The C-bit position is Host family dependent hence user 5680 must provide this value. On EPYC, the value should be 47. 5681 5682 When memory encryption is enabled, we loose certain bits in 5683 physical address space. The ``reduced-phys-bits`` is used to 5684 provide the number of bits we loose in physical address space. 5685 Similar to C-bit, the value is Host family dependent. On EPYC, 5686 a guest will lose a maximum of 1 bit, so the value should be 1. 5687 5688 The ``sev-device`` provides the device file to use for 5689 communicating with the SEV firmware running inside AMD Secure 5690 Processor. The default device is '/dev/sev'. If hardware 5691 supports memory encryption then /dev/sev devices are created by 5692 CCP driver. 5693 5694 The ``policy`` provides the guest policy to be enforced by the 5695 SEV firmware and restrict what configuration and operational 5696 commands can be performed on this guest by the hypervisor. The 5697 policy should be provided by the guest owner and is bound to the 5698 guest and cannot be changed throughout the lifetime of the 5699 guest. The default is 0. 5700 5701 If guest ``policy`` allows sharing the key with another SEV 5702 guest then ``handle`` can be use to provide handle of the guest 5703 from which to share the key. 5704 5705 The ``dh-cert-file`` and ``session-file`` provides the guest 5706 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5707 and session parameters are used for establishing a cryptographic 5708 session with the guest owner to negotiate keys used for 5709 attestation. The file must be encoded in base64. 5710 5711 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5712 cmdline to a designated guest firmware page for measured Linux 5713 boot with -kernel. The default is off. (Since 6.2) 5714 5715 e.g to launch a SEV guest 5716 5717 .. parsed-literal:: 5718 5719 # |qemu_system_x86| \\ 5720 ...... \\ 5721 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5722 -machine ...,memory-encryption=sev0 \\ 5723 ..... 5724 5725 ``-object authz-simple,id=id,identity=string`` 5726 Create an authorization object that will control access to 5727 network services. 5728 5729 The ``identity`` parameter is identifies the user and its format 5730 depends on the network service that authorization object is 5731 associated with. For authorizing based on TLS x509 certificates, 5732 the identity must be the x509 distinguished name. Note that care 5733 must be taken to escape any commas in the distinguished name. 5734 5735 An example authorization object to validate a x509 distinguished 5736 name would look like: 5737 5738 .. parsed-literal:: 5739 5740 # |qemu_system| \\ 5741 ... \\ 5742 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5743 ... 5744 5745 Note the use of quotes due to the x509 distinguished name 5746 containing whitespace, and escaping of ','. 5747 5748 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5749 Create an authorization object that will control access to 5750 network services. 5751 5752 The ``filename`` parameter is the fully qualified path to a file 5753 containing the access control list rules in JSON format. 5754 5755 An example set of rules that match against SASL usernames might 5756 look like: 5757 5758 :: 5759 5760 { 5761 "rules": [ 5762 { "match": "fred", "policy": "allow", "format": "exact" }, 5763 { "match": "bob", "policy": "allow", "format": "exact" }, 5764 { "match": "danb", "policy": "deny", "format": "glob" }, 5765 { "match": "dan*", "policy": "allow", "format": "exact" }, 5766 ], 5767 "policy": "deny" 5768 } 5769 5770 When checking access the object will iterate over all the rules 5771 and the first rule to match will have its ``policy`` value 5772 returned as the result. If no rules match, then the default 5773 ``policy`` value is returned. 5774 5775 The rules can either be an exact string match, or they can use 5776 the simple UNIX glob pattern matching to allow wildcards to be 5777 used. 5778 5779 If ``refresh`` is set to true the file will be monitored and 5780 automatically reloaded whenever its content changes. 5781 5782 As with the ``authz-simple`` object, the format of the identity 5783 strings being matched depends on the network service, but is 5784 usually a TLS x509 distinguished name, or a SASL username. 5785 5786 An example authorization object to validate a SASL username 5787 would look like: 5788 5789 .. parsed-literal:: 5790 5791 # |qemu_system| \\ 5792 ... \\ 5793 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5794 ... 5795 5796 ``-object authz-pam,id=id,service=string`` 5797 Create an authorization object that will control access to 5798 network services. 5799 5800 The ``service`` parameter provides the name of a PAM service to 5801 use for authorization. It requires that a file 5802 ``/etc/pam.d/service`` exist to provide the configuration for 5803 the ``account`` subsystem. 5804 5805 An example authorization object to validate a TLS x509 5806 distinguished name would look like: 5807 5808 .. parsed-literal:: 5809 5810 # |qemu_system| \\ 5811 ... \\ 5812 -object authz-pam,id=auth0,service=qemu-vnc \\ 5813 ... 5814 5815 There would then be a corresponding config file for PAM at 5816 ``/etc/pam.d/qemu-vnc`` that contains: 5817 5818 :: 5819 5820 account requisite pam_listfile.so item=user sense=allow \ 5821 file=/etc/qemu/vnc.allow 5822 5823 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5824 of x509 distinguished names that are permitted access 5825 5826 :: 5827 5828 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5829 5830 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5831 Creates a dedicated event loop thread that devices can be 5832 assigned to. This is known as an IOThread. By default device 5833 emulation happens in vCPU threads or the main event loop thread. 5834 This can become a scalability bottleneck. IOThreads allow device 5835 emulation and I/O to run on other host CPUs. 5836 5837 The ``id`` parameter is a unique ID that will be used to 5838 reference this IOThread from ``-device ...,iothread=id``. 5839 Multiple devices can be assigned to an IOThread. Note that not 5840 all devices support an ``iothread`` parameter. 5841 5842 The ``query-iothreads`` QMP command lists IOThreads and reports 5843 their thread IDs so that the user can configure host CPU 5844 pinning/affinity. 5845 5846 IOThreads use an adaptive polling algorithm to reduce event loop 5847 latency. Instead of entering a blocking system call to monitor 5848 file descriptors and then pay the cost of being woken up when an 5849 event occurs, the polling algorithm spins waiting for events for 5850 a short time. The algorithm's default parameters are suitable 5851 for many cases but can be adjusted based on knowledge of the 5852 workload and/or host device latency. 5853 5854 The ``poll-max-ns`` parameter is the maximum number of 5855 nanoseconds to busy wait for events. Polling can be disabled by 5856 setting this value to 0. 5857 5858 The ``poll-grow`` parameter is the multiplier used to increase 5859 the polling time when the algorithm detects it is missing events 5860 due to not polling long enough. 5861 5862 The ``poll-shrink`` parameter is the divisor used to decrease 5863 the polling time when the algorithm detects it is spending too 5864 long polling without encountering events. 5865 5866 The ``aio-max-batch`` parameter is the maximum number of requests 5867 in a batch for the AIO engine, 0 means that the engine will use 5868 its default. 5869 5870 The IOThread parameters can be modified at run-time using the 5871 ``qom-set`` command (where ``iothread1`` is the IOThread's 5872 ``id``): 5873 5874 :: 5875 5876 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5877ERST 5878 5879 5880HXCOMM This is the last statement. Insert new options before this line! 5881 5882#undef DEF 5883#undef DEFHEADING 5884#undef ARCHHEADING 5885
